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BSC – SEM 3 UNIT 8 PHARMACOLOGY

UNIT-8- Drugs used in treatment of communicable diseases (common infections, infestations)

Drugs Used in the Treatment of Communicable Diseases (Common Infections and Infestations)

Communicable diseases are caused by infectious agents such as bacteria, viruses, fungi, and parasites. The treatment of these diseases requires specific antimicrobial, antiviral, antifungal, or antiparasitic drugs. Below is a comprehensive list of the major drugs used in the treatment of common communicable diseases.


1. Bacterial Infections

Bacterial infections are treated with antibiotics, which inhibit bacterial growth or kill bacteria.

A. Respiratory Infections

DiseaseCausative AgentCommon Drugs Used
Tuberculosis (TB)Mycobacterium tuberculosisFirst-line drugs: Isoniazid (INH), Rifampicin, Ethambutol, Pyrazinamide (HRZE) Second-line drugs: Fluoroquinolones (Levofloxacin, Moxifloxacin), Linezolid
PneumoniaStreptococcus pneumoniae, Haemophilus influenzaeAmoxicillin, Azithromycin, Ceftriaxone
DiphtheriaCorynebacterium diphtheriaePenicillin G, Erythromycin, Diphtheria Antitoxin
Pertussis (Whooping Cough)Bordetella pertussisAzithromycin, Erythromycin

B. Gastrointestinal Infections

DiseaseCausative AgentCommon Drugs Used
CholeraVibrio choleraeDoxycycline, Azithromycin, Ciprofloxacin
Typhoid FeverSalmonella typhiCeftriaxone, Azithromycin, Ciprofloxacin
Bacterial Dysentery (Shigellosis)Shigella spp.Ciprofloxacin, Azithromycin

C. Skin & Soft Tissue Infections

DiseaseCausative AgentCommon Drugs Used
CellulitisStreptococcus pyogenes, Staphylococcus aureusFlucloxacillin, Clindamycin, Ceftriaxone
LeprosyMycobacterium lepraeRifampicin, Dapsone, Clofazimine

2. Viral Infections

Viral infections are treated with antiviral drugs, which inhibit viral replication.

A. Respiratory Infections

DiseaseCausative AgentCommon Drugs Used
Influenza (Flu)Influenza virusOseltamivir, Zanamivir
COVID-19SARS-CoV-2Remdesivir, Molnupiravir, Paxlovid (Nirmatrelvir/Ritonavir)

B. Hepatitis

DiseaseCausative AgentCommon Drugs Used
Hepatitis BHepatitis B virus (HBV)Tenofovir, Entecavir, Interferon-alpha
Hepatitis CHepatitis C virus (HCV)Sofosbuvir, Daclatasvir, Ledipasvir

C. Neurological Infections

DiseaseCausative AgentCommon Drugs Used
RabiesRabies virusRabies vaccine, Rabies immunoglobulin
PolioPoliovirusSupportive care, Polio vaccine

3. Fungal Infections

Fungal infections are treated with antifungal drugs.

Common Fungal Infections

DiseaseCausative AgentCommon Drugs Used
Candidiasis (Oral, Vaginal, Systemic)Candida albicansFluconazole, Amphotericin B
AspergillosisAspergillus spp.Voriconazole, Itraconazole
Dermatophytosis (Ringworm, Athlete’s Foot, Tinea Infections)Trichophyton spp., Microsporum spp., Epidermophyton spp.Terbinafine, Clotrimazole

4. Parasitic Infections

Parasitic infections are treated with antiparasitic drugs.

A. Protozoal Infections

DiseaseCausative AgentCommon Drugs Used
MalariaPlasmodium spp.Artemisinin-based Combination Therapy (ACT) (e.g., Artemether-Lumefantrine, Artesunate + Mefloquine)
AmoebiasisEntamoeba histolyticaMetronidazole, Tinidazole
GiardiasisGiardia lambliaMetronidazole, Albendazole
Leishmaniasis (Kala-Azar)Leishmania donovaniAmphotericin B, Miltefosine

B. Helminthic (Worm) Infections

DiseaseCausative AgentCommon Drugs Used
Ascariasis, Hookworm, PinwormAscaris lumbricoides, Necator americanus, Enterobius vermicularisAlbendazole, Mebendazole
FilariasisWuchereria bancrofti, Brugia malayiDiethylcarbamazine (DEC), Ivermectin

5. Other Infestations

Scabies and Lice Infestation

DiseaseCausative AgentCommon Drugs Used
ScabiesSarcoptes scabieiPermethrin cream, Ivermectin
Head LicePediculus humanus capitisPermethrin, Malathion

Key Points:

  1. Antibiotics should only be used for bacterial infections and not for viral diseases.
  2. Antiviral drugs do not kill viruses but inhibit their replication.
  3. Fungal infections require long-term treatment with antifungal drugs.
  4. Parasitic infections need specific antiparasitic agents, sometimes requiring combination therapy.
  5. Drug resistance is a growing problem, so treatment should be based on confirmed diagnosis and guidelines.

General Principles for the Use of Antimicrobials

The proper use of antimicrobials (antibiotics, antivirals, antifungals, and antiparasitics) is essential to ensure effective treatment, prevent drug resistance, and minimize side effects. Below are the key principles to follow when using antimicrobial agents:


1. Rational Prescribing of Antimicrobials

  • Confirm the Diagnosis: Use clinical evaluation, laboratory tests (culture, PCR, serology), and imaging to ensure the infection is bacterial, viral, fungal, or parasitic.
  • Choose the Right Antimicrobial: Select the most narrow-spectrum drug that effectively targets the pathogen.
  • Follow Guidelines: Adhere to standard treatment protocols like WHO, CDC, and national guidelines.
  • Consider Host Factors: Take into account age, pregnancy, renal/liver function, allergies, and immune status before prescribing.

2. Principles of Effective Antimicrobial Use

PrincipleDescription
Appropriate SelectionChoose the correct antimicrobial based on the causative pathogen, site of infection, and drug susceptibility.
Correct DosageUse the recommended dose to achieve therapeutic levels without causing toxicity.
Optimal DurationAvoid unnecessarily prolonged or short courses to reduce resistance and relapse risk.
Route of AdministrationPrefer oral over IV if possible; use IV for severe infections (e.g., sepsis, meningitis).
Combination TherapyUse multiple drugs only when necessary, e.g., TB (Isoniazid + Rifampicin + Pyrazinamide + Ethambutol).
Monitor Drug LevelsEspecially for narrow therapeutic index drugs (e.g., aminoglycosides, vancomycin).
De-escalation StrategyStart broad-spectrum if needed, then narrow-spectrum after pathogen identification.

3. Prevention of Antimicrobial Resistance (AMR)

  • Avoid Unnecessary Use: Do not use antimicrobials for viral infections (e.g., colds, flu).
  • Complete the Full Course: Ensure patients do not stop early even if they feel better.
  • Prevent Overuse in Agriculture: Minimize antibiotics in livestock and poultry.
  • Practice Infection Control: Hand hygiene, vaccination, and isolation of resistant cases.

4. Special Considerations for Specific Antimicrobials

Drug ClassKey Considerations
Penicillins & CephalosporinsCheck for allergy history (risk of anaphylaxis).
Aminoglycosides (e.g., Gentamicin)Monitor for nephrotoxicity & ototoxicity.
Fluoroquinolones (e.g., Ciprofloxacin)Avoid in pregnancy & children (risk of cartilage damage).
Macrolides (e.g., Azithromycin)Risk of QT prolongation (avoid in heart patients).
Tetracyclines (e.g., Doxycycline)Avoid in pregnant women & children <8 years (tooth discoloration).
Antifungals (e.g., Amphotericin B)Monitor for renal toxicity in long-term use.
Antivirals (e.g., Oseltamivir, Remdesivir)Most effective when started early in disease course.

5. Patient Education and Compliance

  • Explain the Importance: Educate patients about why and how to take antimicrobials.
  • Warn About Side Effects: Inform about potential gastrointestinal upset, allergic reactions, and toxicity signs.
  • Discourage Self-Medication: Avoid leftover antibiotics or using friends’ prescriptions.

6. Role of Health Professionals

  • Prescribe Judiciously: Use antibiotics only when necessary.
  • Promote Stewardship: Encourage hospital antibiotic stewardship programs.
  • Surveillance & Reporting: Monitor local resistance patterns and report drug-resistant cases.

PENICILLIN:

1. Introduction

Penicillin is a β-lactam antibiotic that works by inhibiting bacterial cell wall synthesis, making it effective against Gram-positive and some Gram-negative bacteria. It was the first antibiotic discovered by Alexander Fleming in 1928 and remains one of the most widely used classes of antibiotics.


2. Types of Penicillin

Penicillins are classified into four major types:

TypeExampleSpectrumCommon Uses
Natural PenicillinsPenicillin G, Penicillin VMostly Gram-positive bacteriaStreptococcal infections, Syphilis, Diphtheria, Rheumatic fever prophylaxis
Penicillinase-Resistant (Antistaphylococcal) PenicillinsMethicillin, Oxacillin, Nafcillin, Cloxacillin, DicloxacillinResistant to β-lactamaseStaphylococcal infections (not MRSA)
AminopenicillinsAmoxicillin, AmpicillinExtended spectrum (Gram-positive & some Gram-negative)Otitis media, Sinusitis, UTI, Bronchitis
Extended-Spectrum (Antipseudomonal) PenicillinsPiperacillin, TicarcillinWider spectrum (Pseudomonas, Klebsiella)Severe infections: Sepsis, Pneumonia, UTI

3. Composition

Penicillins contain a β-lactam ring, which is responsible for their antibacterial activity. They may be combined with β-lactamase inhibitors to prevent bacterial resistance:

  • Amoxicillin + Clavulanic Acid (Augmentin)
  • Ampicillin + Sulbactam (Unasyn)
  • Piperacillin + Tazobactam (Zosyn)

4. Mechanism of Action

  • Inhibits bacterial cell wall synthesis by blocking penicillin-binding proteins (PBPs).
  • Leads to cell lysis and death of bacteria.
  • Bactericidal action, effective during bacterial active growth phase.

5. Dosage & Route of Administration

DrugDosageRoute
Penicillin G1-5 million units every 4-6 hrsIV/IM
Penicillin V250-500 mg every 6 hrsOral
Amoxicillin250-500 mg every 8 hrsOral
Ampicillin500-1000 mg every 6 hrsIV/IM
Piperacillin/Tazobactam3.375-4.5 g every 6-8 hrsIV

6. Indications (Uses)

A. Bacterial Infections

  • Respiratory tract infections: Pneumonia, Bronchitis, Pharyngitis
  • Skin & Soft tissue infections: Cellulitis, Abscesses
  • Urinary tract infections (UTI)
  • Meningitis (caused by Neisseria meningitidis, Streptococcus pneumoniae)
  • Syphilis (Treponema pallidum) – Penicillin G is the drug of choice
  • Endocarditis (Streptococcus viridans, Enterococcus)
  • Septicemia
  • Otitis media (Middle ear infection)
  • Diphtheria and Gas gangrene

7. Contraindications

  • Penicillin Allergy/Hypersensitivity: Can cause anaphylaxis
  • History of Stevens-Johnson Syndrome
  • Severe Renal Failure: Dose adjustment needed
  • Mononucleosis: Amoxicillin can cause a rash in patients with Epstein-Barr Virus

8. Drug Interactions

Interacting DrugEffect
ProbenecidIncreases Penicillin levels (delays renal excretion)
MethotrexateIncreases Methotrexate toxicity
TetracyclinesReduces effectiveness of Penicillin
Oral ContraceptivesMay reduce efficacy, use backup contraception
WarfarinIncreases risk of bleeding

9. Side Effects

Common Side Effects
Nausea, Vomiting, Diarrhea
Rash, Itching (Mild allergic reactions)
Abdominal pain
Headache
Oral/Vaginal Candidiasis

10. Adverse Effects

Serious Adverse Effects
Anaphylaxis (Swelling, difficulty breathing, hypotension)
Stevens-Johnson Syndrome (SJS) – Severe skin reaction
Clostridium difficile-associated diarrhea
Neutropenia & Thrombocytopenia
Seizures (in high doses, renal failure patients)

11. Toxicity & Management

  • Toxic Effects: Neurotoxicity (seizures), Nephrotoxicity
  • Management of Overdose:
    • Stop the drug immediately
    • IV fluids & symptomatic treatment
    • Antihistamines, Epinephrine for anaphylaxis
    • Hemodialysis in severe renal toxicity

12. Role of Nurse in Penicillin Administration

A. Assessment

  • Check allergy history before administration.
  • Monitor for signs of hypersensitivity (rash, itching, swelling).
  • Assess renal function in patients with kidney disease.

B. Administration

  • IM Injections: Give deep in the gluteal or thigh muscle.
  • IV Infusion: Dilute with saline or dextrose, give over 30-60 minutes.
  • Oral: Take 1 hour before or 2 hours after food (Penicillin V) but Amoxicillin can be taken with food.

C. Monitoring

  • Watch for allergic reactions (rash, itching, swelling, difficulty breathing).
  • Monitor renal function (creatinine, BUN) in long-term therapy.
  • Observe for diarrhea, indicating possible C. difficile infection.

D. Patient Education

  • Complete full course to prevent resistance.
  • Report signs of allergy (swelling, rash, shortness of breath).
  • Avoid alcohol (can increase drug side effects).
  • Use backup contraception if on oral contraceptives.

Cephalosporins:

1. Introduction

Cephalosporins are β-lactam antibiotics structurally related to penicillins. They work by inhibiting bacterial cell wall synthesis, leading to bacterial lysis and death. They are broad-spectrum antibiotics and are used to treat a variety of Gram-positive and Gram-negative bacterial infections.


2. Classification of Cephalosporins

Cephalosporins are classified into five generations based on their spectrum of activity.

GenerationExamplesSpectrumCommon Uses
First-GenerationCefazolin, CephalexinPrimarily Gram-positive (Staphylococcus, Streptococcus)Skin infections, Surgical prophylaxis, UTI
Second-GenerationCefuroxime, Cefaclor, CefoxitinMore Gram-negative coverage (H. influenzae, Enterobacter)Respiratory infections, Otitis media, UTI
Third-GenerationCeftriaxone, Cefotaxime, CeftazidimeBroad-spectrum, better Gram-negative coverageMeningitis, Pneumonia, Gonorrhea, Sepsis
Fourth-GenerationCefepimeGram-positive + PseudomonasSevere infections: Septicemia, Pneumonia
Fifth-GenerationCeftarolineMRSA + Resistant Gram-negative bacteriaMRSA infections, Skin infections, Pneumonia

3. Composition & Mechanism of Action

  • Composition: Cephalosporins contain a β-lactam ring, which interferes with bacterial cell wall synthesis.
  • Mechanism of Action:
    • Binds to penicillin-binding proteins (PBPs).
    • Inhibits peptidoglycan synthesis, causing bacterial cell lysis.
    • Bactericidal (kills bacteria rather than just inhibiting growth).

4. Dosage & Route of Administration

DrugDosageRoute
Cefazolin1-2g every 8 hrsIV/IM
Cephalexin250-500 mg every 6 hrsOral
Cefuroxime250-500 mg every 8-12 hrsOral, IV
Ceftriaxone1-2g once dailyIV/IM
Cefepime1-2g every 8-12 hrsIV
Ceftaroline600 mg every 12 hrsIV

5. Indications (Uses)

A. Bacterial Infections Treated by Cephalosporins

DiseaseCausative OrganismCommon Cephalosporin Used
PneumoniaStreptococcus pneumoniae, H. influenzaeCeftriaxone, Cefotaxime
UTI (Urinary Tract Infection)E. coli, KlebsiellaCephalexin, Cefuroxime
MeningitisNeisseria meningitidis, S. pneumoniaeCeftriaxone, Cefotaxime
SepsisGram-negative & Gram-positive bacteriaCefepime, Ceftazidime
GonorrheaNeisseria gonorrhoeaeCeftriaxone
Skin & Soft Tissue InfectionsStaphylococcus aureus, StreptococcusCephalexin, Cefazolin
MRSA InfectionsMethicillin-resistant Staphylococcus aureusCeftaroline
Intra-abdominal InfectionsBacteroides fragilisCefoxitin, Cefotetan

6. Contraindications

  • Allergy to Cephalosporins or Penicillins (Cross-reactivity with penicillin allergy)
  • Severe Renal Failure (Dose adjustment required)
  • History of Anaphylaxis to β-lactam antibiotics
  • Neonates (Ceftriaxone + Calcium IV can cause fatal precipitation)

7. Drug Interactions

Interacting DrugEffect
Aminoglycosides (Gentamicin, Amikacin)Increased nephrotoxicity
Loop Diuretics (Furosemide)Increased risk of kidney damage
WarfarinIncreased risk of bleeding (due to vitamin K inhibition)
ProbenecidIncreases cephalosporin levels by reducing excretion

8. Side Effects

Common Side Effects
Nausea, Vomiting, Diarrhea
Rash, Pruritus (Itching)
Pain at Injection Site
Mild Liver Enzyme Elevation
Headache, Dizziness

9. Adverse Effects

Serious Adverse Effects
Anaphylaxis (Severe Allergic Reaction)
Clostridium difficile-associated diarrhea
Neutropenia, Thrombocytopenia (Blood Disorders)
Seizures (Especially with Cefepime in Renal Failure)
Steven-Johnson Syndrome (Rare but life-threatening skin reaction)

10. Toxicity & Management

  • Overdose Symptoms: Neurotoxicity (seizures, confusion), Nephrotoxicity
  • Management:
    • Stop the drug immediately
    • IV fluids for hydration
    • Hemodialysis in severe cases (especially Cefepime toxicity)
    • Seizure control with benzodiazepines (if needed)

11. Role of Nurse in Cephalosporin Administration

A. Pre-Administration Assessment

  • Check for allergy history (cross-sensitivity with penicillin).
  • Assess renal function (especially for Cefepime).
  • Monitor culture and sensitivity reports before choosing the antibiotic.

B. Administration Considerations

  • IM Injections: Give deep intramuscularly in the gluteal or thigh muscle.
  • IV Infusion:
    • Dilute before administration.
    • Ceftriaxone should not be mixed with Calcium-containing IV solutions (risk of fatal precipitates).
  • Oral Forms: Take with or without food, but avoid alcohol.

C. Monitoring During Treatment

  • Watch for signs of allergic reaction (rash, swelling, difficulty breathing).
  • Monitor renal function (especially in elderly or kidney disease patients).
  • Observe for signs of superinfection (e.g., oral thrush, vaginal candidiasis).
  • Check coagulation profile if used long-term (risk of bleeding).

D. Patient Education

  • Complete the full course to prevent resistance.
  • Report any signs of allergy (hives, difficulty breathing).
  • Avoid alcohol (may cause severe nausea, vomiting).
  • Take oral cephalosporins with food if stomach upset occurs.

12. Key Differences Between Cephalosporins & Penicillins

FeatureCephalosporinsPenicillins
Allergy RiskLower than penicillinHigher risk
Spectrum of ActivityBroad-spectrumNarrow to extended-spectrum
Route of AdministrationIV, IM, OralIV, IM, Oral
Common UsesMeningitis, Gonorrhea, PneumoniaStrep throat, Syphilis, Skin infections
β-Lactamase ResistanceMore resistantMore susceptible

Aminoglycosides:

1. Introduction

Aminoglycosides are bactericidal antibiotics that work by inhibiting bacterial protein synthesis. They are highly effective against aerobic Gram-negative bacteria and some Gram-positive bacteria, especially in severe infections.

🔹 Common Uses: Sepsis, Pneumonia, Meningitis, Tuberculosis (TB), and Urinary Tract Infections (UTI).
🔹 Examples: Gentamicin, Amikacin, Tobramycin, Streptomycin, Neomycin.


2. Types of Aminoglycosides

DrugCommon Uses
GentamicinSepsis, UTI, Endocarditis, Pneumonia
AmikacinMulti-drug resistant infections, TB
TobramycinPseudomonas infections, Cystic fibrosis
StreptomycinTuberculosis, Plague
NeomycinTopical infections, Bowel sterilization before surgery
KanamycinRarely used, previously for TB

3. Composition & Mechanism of Action

  • Composition: Contains amino sugars and aminocyclitol.
  • Mechanism of Action:
    • Binds to 30S ribosomal subunit, inhibiting protein synthesis.
    • Causes misreading of mRNA, leading to defective proteins.
    • Bactericidal (kills bacteria rather than just inhibiting growth).

4. Dosage & Route of Administration

DrugDosageRoute
Gentamicin3-5 mg/kg/dayIV, IM
Amikacin15 mg/kg/dayIV, IM
Tobramycin3-5 mg/kg/dayIV, IM, Inhalation
Streptomycin1 g/day (TB)IM
Neomycin500 mg 6-hourly (oral)Oral, Topical

📌 Note: Aminoglycosides are not absorbed orally except Neomycin, which is used for bowel sterilization before surgery.


5. Indications (Uses)

A. Severe Gram-Negative Infections

DiseaseCausative OrganismAminoglycoside Used
SepsisE. coli, Pseudomonas, KlebsiellaGentamicin, Amikacin
Pneumonia (Hospital-acquired)Pseudomonas, KlebsiellaTobramycin, Amikacin
MeningitisListeria, PseudomonasGentamicin, Amikacin
Urinary Tract Infection (UTI)E. coli, Proteus, KlebsiellaGentamicin, Amikacin
EndocarditisEnterococcus, StaphylococcusGentamicin (with β-lactam)
Tuberculosis (TB)Mycobacterium tuberculosisStreptomycin, Amikacin

6. Contraindications

  • Renal Failure (Risk of nephrotoxicity)
  • Pregnancy (Risk of fetal ototoxicity)
  • Myasthenia Gravis (Can worsen muscle weakness)
  • Previous hypersensitivity to aminoglycosides

7. Drug Interactions

Interacting DrugEffect
Loop Diuretics (Furosemide, Ethacrynic Acid)Increased risk of ototoxicity
VancomycinIncreased nephrotoxicity
NSAIDs (Ibuprofen, Diclofenac)Decreased renal clearance, increases toxicity
Neuromuscular Blockers (Succinylcholine, Rocuronium)Prolonged muscle paralysis
CephalosporinsIncreased nephrotoxicity

8. Side Effects

Common Side Effects
Nausea, Vomiting
Dizziness, Headache
Injection site pain
Rash, Itching
Muscle weakness

9. Adverse Effects

Aminoglycosides have serious toxicity risks. The three most dangerous effects are:

Adverse EffectSymptomsManagement
Nephrotoxicity (Kidney Damage)Increased creatinine, BUN, oliguria (low urine output)Monitor renal function, dose adjustment
Ototoxicity (Hearing Loss, Vertigo)Tinnitus, hearing loss, dizziness, balance issuesStop drug, audiometry testing
Neuromuscular BlockadeRespiratory paralysis (rare)Calcium gluconate, ventilatory support

📌 Important: Monitor drug levels (Peak & Trough levels) to prevent toxicity.


10. Toxicity & Management

  • Toxic Effects: Renal failure, Hearing loss, Neuromuscular paralysis.
  • Management of Overdose:
    • Stop the drug immediately.
    • Hydration & Diuretics to flush out the drug.
    • Hemodialysis for severe toxicity.
    • Calcium gluconate for neuromuscular blockade.

11. Role of Nurse in Aminoglycoside Administration

A. Pre-Administration Assessment

  • Check Renal Function (Creatinine, BUN).
  • Assess Hearing (Baseline audiometry if needed).
  • Check for Myasthenia Gravis (Risk of muscle paralysis).
  • Monitor Infection Severity (Culture & Sensitivity reports).

B. Administration Considerations

  • IV Infusion: Give slowly over 30-60 minutes.
  • IM Injection: Give deep intramuscularly (thigh or gluteal muscle).
  • Check Trough Levels:
    • Draw blood just before the next dose (to monitor toxicity).
  • Monitor Peak Levels:
    • Draw 30-60 min after administration.

C. Monitoring During Treatment

  • Watch for signs of toxicity: Kidney function, hearing, and muscle weakness.
  • Check urine output (for early signs of nephrotoxicity).
  • Monitor electrolytes (Aminoglycosides can cause Hypokalemia, Hypocalcemia).

D. Patient Education

  • Report any hearing changes (ringing in ears, dizziness).
  • Drink plenty of water to protect kidneys.
  • Do not take NSAIDs (Ibuprofen, Diclofenac) with aminoglycosides.
  • Complete the full course to prevent resistance.

12. Key Differences Between Aminoglycosides & Other Antibiotics

FeatureAminoglycosidesCephalosporinsPenicillins
SpectrumGram-negativeBroad-spectrumGram-positive & some Gram-negative
RouteIV, IMIV, IM, OralIV, IM, Oral
Toxicity RiskHigh (Kidney, Ear damage)LowLow
Common UsesSepsis, TB, PseudomonasMeningitis, PneumoniaStrep throat, Syphilis

Macrolides:

1. Introduction

Macrolides are bacteriostatic antibiotics that work by inhibiting bacterial protein synthesis. They are effective against Gram-positive bacteria, some Gram-negative bacteria, and atypical pathogens (e.g., Mycoplasma, Chlamydia, Legionella).

🔹 Common Uses: Respiratory infections, Skin infections, STDs (Chlamydia), Atypical pneumonia, Peptic ulcer disease (H. pylori).
🔹 Examples: Erythromycin, Azithromycin, Clarithromycin, Roxithromycin.


2. Types of Macrolides

DrugSpectrumCommon Uses
ErythromycinGram-positive, AtypicalsPneumonia, Diphtheria, Pertussis, Strep throat
AzithromycinBroad-spectrum, AtypicalsPneumonia, Chlamydia, H. pylori, UTI
ClarithromycinGram-positive, Gram-negative, AtypicalsH. pylori infection, Mycobacterium avium complex (MAC)
RoxithromycinGram-positive, AtypicalsRespiratory infections, Skin infections

3. Composition & Mechanism of Action

  • Composition: Macrolides contain a macrocyclic lactone ring.
  • Mechanism of Action:
    • Binds to 50S ribosomal subunit.
    • Inhibits protein synthesis by preventing peptide chain elongation.
    • Bacteriostatic, but can be bactericidal at high doses.

4. Dosage & Route of Administration

DrugDosageRoute
Erythromycin250-500 mg every 6 hrsOral, IV
Azithromycin500 mg once daily for 3-5 daysOral, IV
Clarithromycin250-500 mg every 12 hrsOral
Roxithromycin150 mg every 12 hrsOral

📌 Note: Macrolides are well-absorbed orally, but some forms (e.g., erythromycin) can cause gastrointestinal side effects.


5. Indications (Uses)

A. Respiratory & ENT Infections

DiseaseCausative OrganismMacrolide Used
Community-acquired pneumonia (CAP)Mycoplasma pneumoniae, Chlamydia pneumoniaeAzithromycin, Clarithromycin
Streptococcal PharyngitisStreptococcus pyogenesErythromycin (alternative to penicillin)
Sinusitis & Otitis MediaStreptococcus pneumoniae, H. influenzaeAzithromycin, Clarithromycin
Diphtheria & Pertussis (Whooping Cough)Corynebacterium diphtheriae, Bordetella pertussisErythromycin

B. Sexually Transmitted Infections (STIs)

DiseaseCausative OrganismMacrolide Used
ChlamydiaChlamydia trachomatisAzithromycin (Single dose 1g)
Gonorrhea (Alternative Treatment)Neisseria gonorrhoeaeAzithromycin (along with Ceftriaxone)

C. Gastrointestinal Infections

DiseaseCausative OrganismMacrolide Used
Peptic Ulcer Disease (PUD)Helicobacter pyloriClarithromycin (with Amoxicillin + PPI)

D. Atypical & Mycobacterial Infections

DiseaseCausative OrganismMacrolide Used
Legionnaires’ DiseaseLegionella pneumophilaAzithromycin, Clarithromycin
Mycobacterium Avium Complex (MAC) in HIVM. avium-intracellulareAzithromycin, Clarithromycin

6. Contraindications

  • Severe liver disease (Risk of hepatotoxicity).
  • QT prolongation (Risk of arrhythmias).
  • Hypersensitivity to macrolides.
  • Myasthenia Gravis (Can worsen muscle weakness).

7. Drug Interactions

Interacting DrugEffect
WarfarinIncreases bleeding risk
DigoxinIncreases toxicity risk
Statins (Simvastatin, Atorvastatin)Increased risk of rhabdomyolysis
TheophyllineIncreased toxicity
Antacids (Containing Aluminum or Magnesium)Reduces absorption of Azithromycin

8. Side Effects

Common Side Effects
Nausea, Vomiting, Diarrhea
Abdominal pain
Metallic taste (Clarithromycin)
Headache, Dizziness
Rash, Pruritus

9. Adverse Effects

Serious Adverse Effects
Hepatotoxicity (Liver damage)
QT Prolongation → Arrhythmias (Torsades de Pointes)
Pseudomembranous Colitis (C. difficile Infection)
Steven-Johnson Syndrome (Rare but life-threatening skin reaction)

📌 Note: Azithromycin has a long half-life, so it stays in the body for several days, reducing the need for frequent dosing.


10. Toxicity & Management

  • Toxic Effects: Liver damage, Cardiac arrhythmias.
  • Management of Overdose:
    • Stop the drug immediately.
    • IV fluids & supportive care.
    • Cardiac monitoring for arrhythmias.
    • Activated charcoal in early overdose cases.

11. Role of Nurse in Macrolide Administration

A. Pre-Administration Assessment

  • Check for drug allergies (especially to macrolides).
  • Assess liver function (AST, ALT levels).
  • Monitor ECG in high-risk patients (QT prolongation risk).
  • Check for drug interactions (e.g., Warfarin, Statins).

B. Administration Considerations

  • Oral: Take on empty stomach (except Clarithromycin, which can be taken with food).
  • IV Infusion: Give slowly to prevent cardiac side effects.
  • Avoid antacids (Reduce drug absorption).

C. Monitoring During Treatment

  • Watch for signs of liver damage (jaundice, dark urine).
  • Monitor cardiac function (QT prolongation risk).
  • Observe for gastrointestinal side effects (diarrhea, nausea).

D. Patient Education

  • Complete the full course to prevent resistance.
  • Report severe diarrhea (Risk of C. difficile infection).
  • Avoid grapefruit juice (Increases drug levels).
  • Take Azithromycin once daily due to its long half-life.

12. Key Differences Between Macrolides & Other Antibiotics

FeatureMacrolidesAminoglycosidesPenicillins
SpectrumBroad-spectrumGram-negativeGram-positive
RouteOral, IVIV, IMIV, IM, Oral
Common UsesPneumonia, Chlamydia, H. pyloriSepsis, TB, PseudomonasStrep throat, Syphilis
Toxicity RiskLiver, Heart (QT)Kidney, EarLow

Broad-Spectrum Antibiotics:

1. Introduction

Broad-spectrum antibiotics are antimicrobial agents effective against a wide range of bacteria, including Gram-positive and Gram-negative organisms. They are used when the exact causative organism is unknown or in mixed infections.

🔹 Common Uses: Sepsis, Pneumonia, Meningitis, Intra-abdominal infections, Empirical therapy.
🔹 Examples: Penicillins (Amoxicillin + Clavulanic Acid), Cephalosporins (Ceftriaxone), Macrolides (Azithromycin), Fluoroquinolones (Ciprofloxacin), Carbapenems (Meropenem), and Tetracyclines (Doxycycline).


2. Classification of Broad-Spectrum Antibiotics

Broad-spectrum antibiotics are classified based on their mechanism of action and targeted bacteria.

ClassExamplesMechanism of ActionCoverage
β-Lactams (Penicillins, Cephalosporins, Carbapenems)Amoxicillin-Clavulanate, Ceftriaxone, MeropenemInhibits cell wall synthesisGram-positive, Gram-negative
MacrolidesAzithromycin, ClarithromycinInhibits protein synthesis (50S ribosome)Gram-positive, Atypicals
TetracyclinesDoxycycline, TetracyclineInhibits protein synthesis (30S ribosome)Gram-positive, Gram-negative, Rickettsia
FluoroquinolonesCiprofloxacin, LevofloxacinInhibits DNA replication (DNA gyrase, Topoisomerase)Gram-negative, Atypicals
ChloramphenicolChloramphenicolInhibits protein synthesis (50S ribosome)Broad-spectrum, but toxic
SulfonamidesTrimethoprim-Sulfamethoxazole (Co-trimoxazole)Inhibits folic acid synthesisGram-positive, Gram-negative

3. Indications (Uses)

Broad-spectrum antibiotics are used when:

  • The causative organism is unknown.
  • Polymicrobial infections (involving multiple bacteria).
  • The infection is caused by resistant bacteria.
  • Empirical therapy (before culture results).

A. Respiratory Infections

DiseaseCausative OrganismBroad-Spectrum Antibiotic Used
Pneumonia (Community-acquired)Streptococcus pneumoniae, Mycoplasma pneumoniaeAzithromycin, Levofloxacin, Ceftriaxone
Hospital-Acquired Pneumonia (HAP)Pseudomonas, MRSAMeropenem + Vancomycin
Sinusitis & Otitis MediaStreptococcus pneumoniae, H. influenzaeAmoxicillin-Clavulanate, Cefuroxime

B. Urinary Tract Infections (UTI)

DiseaseCausative OrganismBroad-Spectrum Antibiotic Used
Complicated UTIE. coli, Klebsiella, PseudomonasCiprofloxacin, Meropenem
PyelonephritisGram-negative bacilliCeftriaxone, Levofloxacin

C. Gastrointestinal Infections

DiseaseCausative OrganismBroad-Spectrum Antibiotic Used
Typhoid FeverSalmonella typhiCeftriaxone, Azithromycin
CholeraVibrio choleraeDoxycycline, Azithromycin
Bacterial DysenteryShigella, E. coliCiprofloxacin, Co-trimoxazole

D. Central Nervous System (CNS) Infections

DiseaseCausative OrganismBroad-Spectrum Antibiotic Used
MeningitisNeisseria meningitidis, Streptococcus pneumoniaeCeftriaxone, Meropenem
Brain AbscessMixed bacterial infectionMeropenem, Metronidazole

E. Skin & Soft Tissue Infections

DiseaseCausative OrganismBroad-Spectrum Antibiotic Used
CellulitisStaphylococcus, StreptococcusAmoxicillin-Clavulanate, Cefazolin
Diabetic Foot InfectionsMixed Gram-positive & Gram-negative bacteriaPiperacillin-Tazobactam, Meropenem

F. Sepsis (Life-Threatening Infections)

DiseaseCausative OrganismBroad-Spectrum Antibiotic Used
SepticemiaUnknown sourceCefepime + Vancomycin
Neutropenic Fever (Immunocompromised Patients)Gram-negative bacilli, Fungal pathogensMeropenem, Piperacillin-Tazobactam

4. Contraindications

  • Severe allergy to the specific antibiotic class.
  • Liver or kidney failure (Dose adjustment needed).
  • Pregnancy & breastfeeding (Some broad-spectrum antibiotics like Tetracyclines and Fluoroquinolones are contraindicated).
  • Myasthenia Gravis (Fluoroquinolones can worsen muscle weakness).

5. Drug Interactions

Interacting DrugEffect
WarfarinIncreased risk of bleeding
Antacids (Calcium, Magnesium, Aluminum)Reduces absorption of Fluoroquinolones
Statins (Simvastatin, Atorvastatin)Increased risk of Rhabdomyolysis
DigoxinIncreased toxicity (Macrolides interact)
NSAIDs (Ibuprofen, Diclofenac)Increased risk of kidney damage with certain broad-spectrum antibiotics

6. Side Effects

Common Side Effects
Nausea, Vomiting, Diarrhea
Abdominal pain
Headache, Dizziness
Rash, Pruritus
Superinfection (C. difficile-associated diarrhea, Oral thrush)

7. Adverse Effects

Serious Adverse Effects
C. difficile Infection (Severe Diarrhea)
Nephrotoxicity (Kidney damage – Aminoglycosides, Vancomycin)
Hepatotoxicity (Liver damage – Macrolides, Tetracyclines)
QT Prolongation (Fluoroquinolones, Macrolides)
Photosensitivity (Tetracyclines, Fluoroquinolones)

📌 Note: Some broad-spectrum antibiotics (like Carbapenems) can lower the seizure threshold, increasing the risk of seizures in epileptic patients.


8. Role of Nurse in Broad-Spectrum Antibiotic Administration

A. Pre-Administration Assessment

  • Check for allergies (especially to β-lactams).
  • Monitor renal and liver function tests before starting therapy.
  • Assess infection site and obtain cultures before starting antibiotics.

B. Administration Considerations

  • IV Infusion: Administer over the recommended time to avoid vein irritation.
  • Oral Administration: Avoid dairy with tetracyclines (reduces absorption).
  • Monitor for Drug Interactions: Avoid antacids with Fluoroquinolones.

C. Monitoring During Treatment

  • Watch for signs of allergic reactions (rash, swelling, breathing difficulty).
  • Monitor renal function (for nephrotoxic drugs like Aminoglycosides).
  • Observe for gastrointestinal side effects (risk of C. difficile infection).

D. Patient Education

  • Complete the full course to prevent resistance.
  • Take antibiotics with or without food as advised.
  • Report severe diarrhea (risk of C. difficile colitis).
  • Avoid alcohol with certain antibiotics (e.g., Metronidazole).

Sulfonamides: A Complete Overview

1. Introduction

Sulfonamides (Sulfa drugs) are bacteriostatic antibiotics that inhibit bacterial folic acid synthesis, preventing bacterial growth. They are broad-spectrum antibiotics, effective against both Gram-positive and Gram-negative bacteria.

🔹 Common Uses: Urinary tract infections (UTI), Respiratory infections, Gastrointestinal infections, Pneumocystis jirovecii pneumonia (PJP), and Toxoplasmosis.
🔹 Examples: Sulfamethoxazole-Trimethoprim (Co-trimoxazole), Sulfadiazine, Sulfasalazine, Silver Sulfadiazine.


2. Types of Sulfonamides

DrugCommon Uses
Sulfamethoxazole-Trimethoprim (Co-trimoxazole)UTI, Pneumocystis pneumonia, MRSA infections
SulfadiazineToxoplasmosis (with Pyrimethamine)
SulfasalazineInflammatory Bowel Disease (IBD), Rheumatoid Arthritis
Silver Sulfadiazine (Topical)Burn Wounds, Skin Infections

📌 Note: Trimethoprim is combined with Sulfamethoxazole (Co-trimoxazole) for a synergistic effect, making it more effective.


3. Composition & Mechanism of Action

  • Composition: Synthetic derivatives of p-aminobenzoic acid (PABA).
  • Mechanism of Action:
    • Inhibits Dihydropteroate Synthase, blocking folic acid synthesis.
    • Prevents bacterial DNA synthesis.
    • Bacteriostatic (stops bacterial growth).

📌 Note: Bacteria need folic acid for survival, but humans obtain folic acid from diet, so sulfonamides selectively target bacteria.


4. Dosage & Route of Administration

DrugDosageRoute
Co-trimoxazole (Sulfamethoxazole 400 mg + Trimethoprim 80 mg)1 tablet every 12 hrsOral, IV
Sulfadiazine500-1000 mg every 6 hrsOral
Sulfasalazine500-1000 mg every 8-12 hrsOral
Silver SulfadiazineApply thin layer every 12 hrsTopical

📌 Note: Take with plenty of water to prevent crystalluria (kidney stone formation).


5. Indications (Uses)

A. Urinary & Renal Infections

DiseaseCausative OrganismSulfonamide Used
Urinary Tract Infection (UTI)E. coli, Proteus, KlebsiellaCo-trimoxazole
ProstatitisGram-negative bacilliCo-trimoxazole

B. Respiratory Infections

DiseaseCausative OrganismSulfonamide Used
Pneumonia (PJP in HIV patients)Pneumocystis jiroveciiCo-trimoxazole
Bronchitis & SinusitisStreptococcus pneumoniae, H. influenzaeCo-trimoxazole

C. Gastrointestinal Infections

DiseaseCausative OrganismSulfonamide Used
Traveler’s DiarrheaEnterotoxigenic E. coliCo-trimoxazole
Shigellosis (Bacterial Dysentery)Shigella speciesCo-trimoxazole

D. Parasitic Infections

DiseaseCausative OrganismSulfonamide Used
ToxoplasmosisToxoplasma gondiiSulfadiazine + Pyrimethamine

E. Dermatological & Autoimmune Conditions

DiseaseConditionSulfonamide Used
Burn WoundsInfection preventionSilver Sulfadiazine (Topical)
Inflammatory Bowel Disease (IBD)Ulcerative colitis, Crohn’s diseaseSulfasalazine
Rheumatoid ArthritisAutoimmune arthritisSulfasalazine

6. Contraindications

  • Sulfa Allergy (Hypersensitivity)
  • Severe Liver or Kidney Disease
  • Pregnancy (First Trimester, Risk of Kernicterus in newborns)
  • Neonates (Risk of Hyperbilirubinemia)
  • G6PD Deficiency (Risk of Hemolysis)

📌 Note: Avoid in pregnant women and neonates due to the risk of bilirubin displacement, leading to kernicterus (brain damage).


7. Drug Interactions

Interacting DrugEffect
WarfarinIncreased risk of bleeding
Oral Hypoglycemics (Sulfonylureas)Increased hypoglycemia risk
PhenytoinIncreased toxicity
MethotrexateIncreased toxicity (competes for protein binding)
Diuretics (Thiazides, Furosemide)Increased risk of allergic reactions

8. Side Effects

Common Side Effects
Nausea, Vomiting, Diarrhea
Rash, Photosensitivity
Headache, Dizziness
Crystalluria (Kidney stones)
Loss of appetite

📌 Prevention: Increase fluid intake to prevent kidney stone formation.


9. Adverse Effects

Serious Adverse Effects
Stevens-Johnson Syndrome (SJS) & Toxic Epidermal Necrolysis (TEN)
Aplastic Anemia & Bone Marrow Suppression
Hemolysis in G6PD Deficiency
Kernicterus in Neonates (Bilirubin toxicity)
Hepatotoxicity (Liver damage)

📌 Important: Stop immediately if rash or fever develops, as SJS/TEN is life-threatening.


10. Toxicity & Management

  • Toxic Effects: Severe allergic reactions, Liver toxicity, Blood disorders.
  • Management of Overdose:
    • Stop the drug immediately.
    • IV fluids & urine alkalinization (for crystalluria).
    • Hemodialysis in severe cases.
    • Folic acid supplementation (to prevent bone marrow suppression).

11. Role of Nurse in Sulfonamide Administration

A. Pre-Administration Assessment

  • Check for Sulfa Allergy (Cross-reactivity with some diuretics & sulfonylureas).
  • Assess renal function (Creatinine, BUN levels).
  • Monitor liver function tests.
  • Check for G6PD Deficiency (Risk of hemolysis).

B. Administration Considerations

  • Oral: Take with plenty of water to prevent kidney stones.
  • IV Infusion: Administer slowly to prevent vein irritation.
  • Topical (Silver Sulfadiazine): Apply thin layer over burn wounds.

C. Monitoring During Treatment

  • Observe for allergic reactions (rash, fever, breathing difficulty).
  • Monitor for skin reactions (Stevens-Johnson Syndrome).
  • Assess urine output (risk of crystalluria).
  • Check blood counts regularly (risk of bone marrow suppression).

D. Patient Education

  • Drink plenty of water to prevent kidney stones.
  • Avoid direct sunlight (risk of photosensitivity).
  • Report skin rash or unusual bleeding immediately.
  • Do not take with antacids (may reduce effectiveness).

Quinolones:

1. Introduction

Quinolones (Fluoroquinolones) are bactericidal antibiotics that work by inhibiting bacterial DNA synthesis, leading to bacterial cell death. They are effective against Gram-negative and some Gram-positive bacteria, making them broad-spectrum antibiotics.

🔹 Common Uses: Urinary tract infections (UTI), Respiratory infections, Gastrointestinal infections, Bone infections, and Sexually transmitted infections (STIs).
🔹 Examples: Ciprofloxacin, Levofloxacin, Moxifloxacin, Ofloxacin, Norfloxacin.


2. Types of Quinolones

Quinolones are divided into four generations based on their antimicrobial spectrum.

GenerationExamplesSpectrumCommon Uses
First-GenerationNalidixic AcidNarrow (Only Gram-negative)Uncomplicated UTI
Second-GenerationCiprofloxacin, Norfloxacin, OfloxacinBroad (More Gram-negative, some Gram-positive)UTI, GI infections, Respiratory infections
Third-GenerationLevofloxacinExtended spectrum (More Gram-positive, including Streptococcus pneumoniae)Pneumonia, Sinusitis, Skin infections
Fourth-GenerationMoxifloxacin, GemifloxacinBroad-spectrum (Gram-positive, Anaerobes)Severe pneumonia, Complicated infections

📌 Note: Ciprofloxacin has strong Gram-negative activity, while Moxifloxacin covers anaerobes.


3. Composition & Mechanism of Action

  • Composition: Synthetic broad-spectrum antimicrobial agents.
  • Mechanism of Action:
    • Inhibits DNA Gyrase & Topoisomerase IV, enzymes necessary for bacterial DNA replication.
    • Prevents bacterial DNA unwinding and synthesis.
    • Bactericidal (Kills bacteria rather than just inhibiting growth).

📌 Note: Humans do not have DNA gyrase, so these drugs selectively target bacteria.


4. Dosage & Route of Administration

DrugDosageRoute
Ciprofloxacin250-750 mg every 12 hrsOral, IV
Levofloxacin500-750 mg once dailyOral, IV
Moxifloxacin400 mg once dailyOral, IV
Ofloxacin200-400 mg every 12 hrsOral, IV
Norfloxacin400 mg every 12 hrsOral

📌 Note: Avoid dairy products & antacids while taking fluoroquinolones (reduces absorption).


5. Indications (Uses)

A. Urinary Tract & Kidney Infections

DiseaseCausative OrganismQuinolone Used
Uncomplicated UTIE. coli, Proteus, KlebsiellaCiprofloxacin, Norfloxacin
Complicated UTI & PyelonephritisPseudomonas, EnterobacterLevofloxacin

B. Respiratory Infections

DiseaseCausative OrganismQuinolone Used
Pneumonia (Community-acquired)Streptococcus pneumoniae, LegionellaLevofloxacin, Moxifloxacin
Sinusitis & BronchitisH. influenzae, M. pneumoniaeMoxifloxacin

C. Gastrointestinal Infections

DiseaseCausative OrganismQuinolone Used
Traveler’s DiarrheaE. coliCiprofloxacin
Typhoid FeverSalmonella typhiCiprofloxacin

D. Bone & Joint Infections

DiseaseCausative OrganismQuinolone Used
OsteomyelitisStaphylococcus aureusCiprofloxacin
Septic ArthritisGram-negative bacilliLevofloxacin

E. Sexually Transmitted Infections (STIs)

DiseaseCausative OrganismQuinolone Used
Gonorrhea (Alternative Treatment)Neisseria gonorrhoeaeCiprofloxacin

F. Skin & Soft Tissue Infections

DiseaseCausative OrganismQuinolone Used
Diabetic Foot InfectionsMixed Gram-positive & Gram-negativeLevofloxacin, Moxifloxacin

6. Contraindications

  • Pregnancy & Breastfeeding (Risk of cartilage damage).
  • Children under 18 years (Risk of tendon rupture, cartilage toxicity).
  • Myasthenia Gravis (May worsen muscle weakness).
  • Severe renal or liver disease (Dose adjustment needed).

📌 Note: Avoid in athletes due to risk of tendon rupture.


7. Drug Interactions

Interacting DrugEffect
Antacids (Calcium, Magnesium, Aluminum, Iron)Reduces absorption
WarfarinIncreases bleeding risk
NSAIDs (Ibuprofen, Diclofenac)Increased risk of seizures
TheophyllineIncreased toxicity
Steroids (Prednisone, Dexamethasone)Increases risk of tendon rupture

8. Side Effects

Common Side Effects
Nausea, Vomiting, Diarrhea
Headache, Dizziness
Photosensitivity (Skin reaction to sunlight)
Loss of appetite
Insomnia

📌 Prevention: Avoid sunlight & use sunscreen while on quinolones.


9. Adverse Effects

Serious Adverse Effects
Tendon Rupture (Achilles tendon rupture risk)
QT Prolongation → Arrhythmias (Torsades de Pointes)
C. difficile Infection (Severe Diarrhea)
Neurotoxicity (Seizures, Hallucinations, Peripheral Neuropathy)
Hepatotoxicity (Liver toxicity)

📌 Important: Discontinue immediately if tendon pain, arrhythmia, or severe diarrhea occurs.


10. Toxicity & Management

  • Toxic Effects: Seizures, Heart arrhythmias, Liver toxicity.
  • Management of Overdose:
    • Stop the drug immediately.
    • IV fluids & supportive care.
    • Activated charcoal in early overdose cases.
    • Cardiac monitoring for QT prolongation.

11. Role of Nurse in Quinolone Administration

A. Pre-Administration Assessment

  • Check for drug allergies (especially previous fluoroquinolone use).
  • Assess renal & liver function (Creatinine, ALT, AST).
  • Monitor ECG in high-risk patients (QT prolongation risk).

B. Administration Considerations

  • Oral: Take on an empty stomach for better absorption.
  • IV Infusion: Give slowly over 60 minutes.
  • Avoid dairy & antacids (reduces absorption).

C. Monitoring During Treatment

  • Watch for signs of tendon pain/swelling.
  • Monitor cardiac function (QT prolongation risk).
  • Observe for neurological side effects (confusion, seizures).

D. Patient Education

  • Complete the full course to prevent resistance.
  • Avoid strenuous exercise (risk of tendon rupture).
  • Use sunscreen to prevent photosensitivity.
  • Do not take with dairy, iron, or antacids.

Miscellaneous Antimicrobials:

1. Introduction

Miscellaneous antimicrobials are a diverse group of antibiotics that do not fit into the major categories like β-lactams, aminoglycosides, macrolides, fluoroquinolones, or sulfonamides. They have unique mechanisms of action and are used for specific infections, including drug-resistant bacteria, anaerobic infections, and atypical pathogens.

🔹 Common Uses: MRSA, Anaerobic infections, Tuberculosis, Fungal infections, Protozoal infections.
🔹 Examples: Vancomycin, Clindamycin, Metronidazole, Linezolid, Daptomycin, Rifampin, Nitrofurantoin.


2. Classification of Miscellaneous Antimicrobials

ClassExamplesMechanism of ActionCommon Uses
GlycopeptidesVancomycin, TeicoplaninInhibits bacterial cell wall synthesisMRSA, C. difficile, Endocarditis
LincosamidesClindamycinInhibits protein synthesis (50S ribosome)Anaerobic infections, Staphylococcal infections
OxazolidinonesLinezolidInhibits protein synthesis (50S ribosome)MRSA, VRE infections
LipopeptidesDaptomycinDisrupts bacterial cell membraneMRSA, Endocarditis
NitroimidazolesMetronidazole, TinidazoleForms toxic radicals that damage DNAAnaerobic infections, Protozoal infections
RifamycinsRifampin, RifabutinInhibits RNA polymeraseTuberculosis, Meningitis prophylaxis
NitrofuransNitrofurantoinDamages bacterial DNAUrinary tract infections
PolymyxinsPolymyxin B, ColistinDisrupts bacterial cell membraneMulti-drug resistant Gram-negative infections

3. Detailed Overview of Miscellaneous Antimicrobials

A. Glycopeptides (Vancomycin, Teicoplanin)

FeatureDetails
MechanismInhibits bacterial cell wall synthesis by binding to D-Ala-D-Ala terminus.
SpectrumGram-positive (MRSA, C. difficile, Streptococci).
IndicationsMRSA infections, C. difficile colitis (Oral Vancomycin), Endocarditis.
DosageIV: 15-20 mg/kg every 8-12 hrs; Oral: 125-250 mg for C. difficile.
Side EffectsNephrotoxicity, Ototoxicity, Red Man Syndrome (Histamine release).
MonitoringMonitor serum vancomycin trough levels to prevent toxicity.

B. Lincosamides (Clindamycin)

FeatureDetails
MechanismInhibits 50S ribosomal subunit, preventing protein synthesis.
SpectrumGram-positive, anaerobes, some MRSA coverage.
IndicationsSkin infections, Bone infections, Anaerobic infections, Streptococcal infections.
Dosage300-600 mg every 6-8 hrs (Oral, IV).
Side EffectsPseudomembranous colitis (C. difficile infection), Diarrhea, Rash.
ContraindicationsHistory of C. difficile-associated diarrhea.

C. Oxazolidinones (Linezolid)

FeatureDetails
MechanismBinds to 50S ribosome, preventing protein synthesis.
SpectrumGram-positive (MRSA, VRE).
IndicationsMRSA pneumonia, VRE infections, Resistant Gram-positive infections.
Dosage600 mg every 12 hrs (Oral, IV).
Side EffectsBone marrow suppression (Thrombocytopenia), Peripheral neuropathy.
Drug InteractionsAvoid SSRIs (Risk of serotonin syndrome).

D. Lipopeptides (Daptomycin)

FeatureDetails
MechanismDisrupts bacterial cell membrane by creating pores.
SpectrumGram-positive (MRSA, VRE).
IndicationsMRSA bacteremia, Endocarditis, Osteomyelitis.
Dosage4-6 mg/kg IV once daily.
Side EffectsMyopathy, Elevated CPK levels (Monitor muscle enzymes).
ContraindicationsNot used for pneumonia (Inactivated by surfactant).

E. Nitroimidazoles (Metronidazole, Tinidazole)

FeatureDetails
MechanismProduces free radicals that damage bacterial DNA.
SpectrumAnaerobes, Protozoa (Giardia, Trichomonas).
IndicationsC. difficile colitis, Bacterial vaginosis, Amebiasis, H. pylori infection.
Dosage500 mg every 8 hrs (Oral, IV).
Side EffectsMetallic taste, Disulfiram-like reaction (Avoid alcohol).
ContraindicationsAlcohol consumption (Severe nausea, vomiting).

F. Rifamycins (Rifampin, Rifabutin)

FeatureDetails
MechanismInhibits RNA polymerase, stopping bacterial RNA synthesis.
SpectrumGram-positive, Gram-negative, Mycobacteria (TB, Leprosy).
IndicationsTuberculosis, Meningitis prophylaxis, MRSA (in combination).
DosageTB: 10 mg/kg/day, Meningitis Prophylaxis: 600 mg/day for 2 days.
Side EffectsHepatotoxicity, Orange-colored urine/sweat/tears.
Drug InteractionsInduces CYP450 (Reduces efficacy of Warfarin, Oral contraceptives).

G. Nitrofurans (Nitrofurantoin)

FeatureDetails
MechanismDamages bacterial DNA by producing reactive metabolites.
SpectrumGram-positive, Gram-negative (UTI pathogens).
IndicationsUncomplicated UTI (E. coli, Staphylococcus saprophyticus).
Dosage100 mg every 12 hrs for 5-7 days.
Side EffectsNausea, Pulmonary fibrosis (long-term use).
ContraindicationsSevere kidney disease (CrCl < 30 mL/min).

H. Polymyxins (Colistin, Polymyxin B)

FeatureDetails
MechanismDisrupts bacterial outer membrane, causing cell death.
SpectrumGram-negative MDR bacteria (Pseudomonas, Acinetobacter, Klebsiella).
IndicationsMulti-drug resistant infections, Pneumonia, Bacteremia.
DosageIV: 2.5-5 mg/kg/day.
Side EffectsNephrotoxicity, Neurotoxicity.
MonitoringRenal function tests (Creatinine, BUN).

Anaerobic Infections:

1. Introduction

Anaerobic infections are caused by bacteria that thrive in low-oxygen (anaerobic) environments. These infections often occur in deep wounds, abscesses, the gastrointestinal (GI) tract, oral cavity, and female reproductive organs.

🔹 Common Anaerobic Bacteria:

  • Gram-positive: Clostridium spp., Peptostreptococcus spp.
  • Gram-negative: Bacteroides fragilis, Fusobacterium spp., Prevotella spp.

🔹 Common Sites of Infection:

  • Oral cavity (Dental abscess, Ludwig’s angina)
  • Gastrointestinal tract (Peritonitis, Appendicitis, Liver abscess)
  • Genital tract (Pelvic inflammatory disease – PID)
  • Skin & soft tissue (Gas gangrene, Necrotizing fasciitis)

2. Common Anaerobic Infections & Causative Organisms

DiseaseCausative Organism(s)Common Sites
Lung AbscessBacteroides, Fusobacterium, PeptostreptococcusLungs
PeritonitisBacteroides fragilis, Clostridium spp.Abdomen
AppendicitisBacteroides fragilisAppendix
Liver AbscessBacteroides, FusobacteriumLiver
Gas GangreneClostridium perfringensSkin & Muscles
Diabetic Foot InfectionBacteroides, PeptostreptococcusFeet (soft tissue)
Necrotizing FasciitisClostridium perfringens, BacteroidesSkin & Muscle
Pelvic Inflammatory Disease (PID)Bacteroides fragilis, PrevotellaFemale Reproductive Organs
Bacterial VaginosisGardnerella vaginalis, MobiluncusVagina

3. Clinical Features of Anaerobic Infections

  • Foul-smelling discharge (common sign of anaerobic growth)
  • Tissue necrosis (gangrene, abscess formation)
  • Gas production (seen in Clostridium perfringens infections)
  • Deep-seated infections (abscesses, osteomyelitis)
  • Poor response to standard antibiotics (penicillins, aminoglycosides)

4. Diagnosis of Anaerobic Infections

A. Laboratory Investigations

TestPurpose
Gram Staining & MicroscopyIdentifies Gram-positive or Gram-negative anaerobes
Anaerobic Culture & SensitivityConfirms anaerobic bacteria
Gas Chromatography (GC)Detects metabolic byproducts
Blood CultureIdentifies systemic anaerobic infections
Radiological Imaging (CT, MRI, X-ray)Detects abscesses, necrotic tissue, gas formation

5. Treatment of Anaerobic Infections

Treatment requires antibiotics targeting anaerobes, surgical intervention (if necessary), and supportive care.

A. Antibiotics Used in Anaerobic Infections

ClassExamplesMechanism of ActionCommon Uses
NitroimidazolesMetronidazole, TinidazoleForms toxic radicals that damage DNAFirst-line for anaerobic infections, C. difficile, Bacterial vaginosis
Beta-Lactam + β-lactamase inhibitorsAmoxicillin-Clavulanate, Piperacillin-TazobactamInhibits bacterial cell wall synthesisLung abscess, Peritonitis, Appendicitis
CarbapenemsMeropenem, ImipenemBroad-spectrum inhibition of cell wall synthesisSevere polymicrobial infections
ClindamycinClindamycinInhibits 50S ribosome, blocking protein synthesisOral & soft tissue infections, Aspiration pneumonia
GlycopeptidesVancomycin (for C. difficile colitis)Inhibits bacterial cell wall synthesisSevere C. difficile infection

📌 Note:

  • Metronidazole + Beta-lactams are the most effective combination for anaerobic infections.
  • Carbapenems are reserved for severe infections or multidrug-resistant cases.
  • Clindamycin is preferred for lung abscesses and dental infections.

B. Surgical Management

In severe anaerobic infections, surgery may be required:

  • Abscess drainage (Liver abscess, Lung abscess)
  • Debridement of necrotic tissue (Gas gangrene, Necrotizing fasciitis)
  • Amputation (Severe diabetic foot infection)
  • Colostomy (Severe abdominal infections)

6. Antibiotic Selection Based on Anaerobic Infection Type

Infection TypeFirst-Line TreatmentAlternative Treatment
Oral/Dental InfectionsClindamycinMetronidazole + Amoxicillin
Aspiration PneumoniaClindamycinPiperacillin-Tazobactam
Lung AbscessMetronidazole + Beta-lactamClindamycin
Abdominal Infections (Peritonitis, Appendicitis)Piperacillin-Tazobactam, CarbapenemsMetronidazole + Ceftriaxone
Gas Gangrene (Clostridial Myonecrosis)Penicillin G + ClindamycinMetronidazole
Diabetic Foot InfectionPiperacillin-TazobactamMetronidazole + Ciprofloxacin
C. difficile ColitisOral VancomycinMetronidazole
Pelvic Inflammatory Disease (PID)Metronidazole + DoxycyclineClindamycin

7. Contraindications & Precautions for Anaerobic Infection Treatment

AntibioticContraindications
MetronidazoleAvoid alcohol (Disulfiram-like reaction)
ClindamycinRisk of C. difficile colitis
CarbapenemsAvoid in seizures (lowers seizure threshold)
Vancomycin (Oral)Only for C. difficile colitis, not systemic infections

8. Role of Nurse in Managing Anaerobic Infections

A. Pre-Administration Assessment

  • Assess infection site (wound, abscess, lungs, GI tract).
  • Check laboratory reports (anaerobic culture, Gram stain, radiology).
  • Evaluate patient history (drug allergies, kidney/liver function).

B. Administration Considerations

  • Metronidazole: Avoid alcohol (causes severe nausea, vomiting).
  • IV Vancomycin: Infuse slowly over 60 min to avoid Red Man Syndrome.
  • Monitor Clindamycin use: Risk of C. difficile colitis (persistent diarrhea).
  • Piperacillin-Tazobactam: Check for penicillin allergy before administration.

C. Monitoring During Treatment

  • Watch for allergic reactions (rash, swelling, breathing difficulty).
  • Monitor kidney & liver function (especially with Metronidazole & Carbapenems).
  • Assess for C. difficile-associated diarrhea (especially with Clindamycin use).

D. Patient Education

  • Complete the full course of antibiotics to prevent resistance.
  • Avoid alcohol with Metronidazole (causes severe vomiting).
  • Report severe diarrhea (sign of C. difficile colitis).
  • Use probiotics to prevent antibiotic-associated diarrhea.

Antitubercular Drugs:

1. Introduction

Antitubercular drugs are used to treat Tuberculosis (TB), a bacterial infection caused by Mycobacterium tuberculosis. The treatment requires long-term therapy with a combination of drugs to prevent resistance and relapse.

🔹 Commonly Used Drugs: Isoniazid (INH), Rifampin, Pyrazinamide, Ethambutol, Streptomycin.
🔹 Standard Therapy: Directly Observed Treatment, Short-course (DOTS) under the Revised National TB Control Program (RNTCP).


2. Classification of Antitubercular Drugs

Antitubercular drugs are classified into First-Line Drugs (most effective with fewer side effects) and Second-Line Drugs (used for drug-resistant TB).

A. First-Line Antitubercular Drugs (Standard TB Treatment)

DrugMechanism of ActionCommon Side Effects
Isoniazid (INH)Inhibits mycolic acid synthesis (essential for cell wall)Hepatotoxicity, Peripheral neuropathy
Rifampin (RIF)Inhibits RNA polymerase, stopping bacterial RNA synthesisHepatotoxicity, Orange-colored urine & sweat
Pyrazinamide (PZA)Disrupts membrane function, acidic environment kills TBHepatitis, Hyperuricemia (Gout)
Ethambutol (EMB)Inhibits arabinosyl transferase, blocking cell wall synthesisOptic neuritis (color blindness)
Streptomycin (SM)Inhibits protein synthesis by binding to the 30S ribosomeNephrotoxicity, Ototoxicity

📌 Mnemonic for First-Line Drugs: “RIPE-S” (Rifampin, Isoniazid, Pyrazinamide, Ethambutol, Streptomycin).


B. Second-Line Antitubercular Drugs (Used in Drug-Resistant TB)

DrugMechanism of ActionCommon Uses
Levofloxacin, MoxifloxacinInhibits DNA GyraseMDR-TB, XDR-TB
Kanamycin, AmikacinInhibits protein synthesisDrug-resistant TB
EthionamideInhibits mycolic acid synthesisMDR-TB
CycloserineInhibits cell wall synthesisMDR-TB, XDR-TB
BedaquilineInhibits ATP Synthase (New TB drug)MDR-TB
DelamanidInhibits mycolic acid synthesisXDR-TB

📌 Note: MDR-TB (Multidrug-Resistant TB) is resistant to INH & Rifampin, while XDR-TB (Extensively Drug-Resistant TB) is resistant to INH, Rifampin, Fluoroquinolones, and at least one injectable second-line drug.


3. Standard Tuberculosis Treatment Regimen (DOTS Therapy)

A. Drug-Sensitive TB Treatment

PhaseDurationDrugs Used
Intensive Phase2 monthsIsoniazid (H), Rifampin (R), Pyrazinamide (Z), Ethambutol (E) (HRZE)
Continuation Phase4 monthsIsoniazid (H), Rifampin (R) (HR)

📌 Total duration = 6 months (for new TB cases).


B. Drug-Resistant TB Treatment (MDR-TB, XDR-TB)

Type of TBDurationDrugs Used
MDR-TB18-24 monthsFluoroquinolones + Injectable Aminoglycoside + 2 Other Second-Line Drugs
XDR-TB24+ monthsBedaquiline, Linezolid, Delamanid + Other Second-Line Drugs

📌 Note: MDR-TB & XDR-TB require longer treatment and stronger drugs, increasing toxicity risk.


4. Side Effects & Adverse Reactions of Antitubercular Drugs

DrugMajor Side Effects
Isoniazid (INH)Hepatitis, Peripheral Neuropathy (Prevent with Vitamin B6 – Pyridoxine)
Rifampin (RIF)Orange-colored urine & sweat, Hepatotoxicity, Drug interactions (Induces CYP450)
Pyrazinamide (PZA)Hepatotoxicity, Hyperuricemia (Gout), Joint pain
Ethambutol (EMB)Optic Neuritis (Color blindness, Blurred vision)
Streptomycin (SM)Nephrotoxicity, Ototoxicity (Hearing loss, Vertigo)

📌 Key Points:

  • Always monitor liver function (LFTs) in patients on TB therapy.
  • Vitamin B6 (Pyridoxine) is given with INH to prevent neuropathy.
  • Rifampin reduces the effectiveness of oral contraceptives.
  • Patients should be educated about urine discoloration with Rifampin (harmless side effect).

5. Drug Interactions

Interacting DrugEffect
Rifampin + WarfarinReduces Warfarin levels (increased clot risk)
Rifampin + Oral ContraceptivesReduces effectiveness (risk of pregnancy)
Isoniazid + PhenytoinIncreases Phenytoin toxicity
Ethambutol + AntacidsDecreased absorption
Fluoroquinolones (Levofloxacin, Moxifloxacin) + AntacidsReduced absorption (Take fluoroquinolones 2 hours before/after antacids)

6. Role of Nurse in TB Treatment

A. Pre-Administration Assessment

  • Check baseline liver function tests (LFTs) before starting therapy.
  • Assess vision before starting Ethambutol (to detect early optic neuritis).
  • Check for symptoms of neuropathy (tingling, numbness) in patients on INH.
  • Assess kidney function before giving Streptomycin.

B. Administration Considerations

  • Take Rifampin on an empty stomach (better absorption).
  • Avoid alcohol during TB treatment (increases liver toxicity).
  • Give Pyridoxine (Vitamin B6) with INH to prevent neuropathy.
  • Ensure patient compliance with DOTS therapy.

C. Monitoring During Treatment

  • Watch for signs of liver toxicity (jaundice, dark urine, nausea).
  • Monitor vision regularly in Ethambutol therapy.
  • Assess for hearing loss in patients taking Streptomycin.
  • Monitor kidney function in patients on Aminoglycosides (Streptomycin, Amikacin).

D. Patient Education

  • Complete the full TB course (prevents resistance & relapse).
  • Report any jaundice, vision changes, or numbness.
  • Avoid alcohol (reduces liver damage).
  • Expect orange-colored urine/sweat with Rifampin (Harmless).
  • Use alternative contraception (Rifampin reduces oral contraceptive effectiveness).

7. TB Prevention Strategies

  • BCG Vaccine (Bacillus Calmette-Guérin): Given to newborns for TB protection.
  • Preventive Therapy: Isoniazid for latent TB in high-risk individuals.
  • Isolation of TB patients (Airborne precautions).
  • DOTS therapy adherence to prevent MDR-TB.

Anti-Leprosy Drugs:

1. Introduction

Leprosy (Hansen’s disease) is a chronic infectious disease caused by Mycobacterium leprae. It primarily affects the skin, peripheral nerves, mucosa of the upper respiratory tract, and eyes. Treatment requires long-term multidrug therapy (MDT) to prevent drug resistance and complications.

🔹 Standard Therapy: Multidrug Therapy (MDT) recommended by WHO.
🔹 First-Line Drugs: Dapsone, Rifampin, Clofazimine.
🔹 Second-Line Drugs: Minocycline, Ofloxacin, Clarithromycin.


2. Classification of Anti-Leprosy Drugs

Anti-leprosy drugs are classified into First-Line (MDT drugs) and Second-Line (used for drug-resistant or relapsed cases).

A. First-Line Anti-Leprosy Drugs (Standard MDT Therapy)

DrugMechanism of ActionCommon Side Effects
Dapsone (DDS)Inhibits dihydropteroate synthase, blocking folic acid synthesisHemolysis (G6PD deficiency), Skin rash
Rifampin (RIF)Inhibits RNA polymerase, stopping bacterial RNA synthesisHepatotoxicity, Orange-colored urine & sweat
Clofazimine (CLF)Binds to mycobacterial DNA, disrupting functionSkin pigmentation (red-black discoloration), GI upset

📌 Mnemonic for First-Line Drugs: “DRC” (Dapsone, Rifampin, Clofazimine).


B. Second-Line Anti-Leprosy Drugs (For Drug-Resistant or Relapsed Leprosy)

DrugMechanism of ActionCommon Uses
MinocyclineInhibits protein synthesis (30S ribosome)Alternative for Dapsone
OfloxacinInhibits DNA GyraseUsed in Rifampin-resistant cases
ClarithromycinInhibits protein synthesis (50S ribosome)Used in Drug-Resistant Leprosy
ThalidomideSuppresses TNF-alpha, reduces inflammationLeprosy reactions (Type 2 Erythema Nodosum Leprosum – ENL)

📌 Note: **Thalidomide is teratogenic and should be avoided in pregnancy.


3. WHO Recommended Multidrug Therapy (MDT)

Multidrug Therapy (MDT) is based on the disease classification:

  • Paucibacillary (PB) Leprosy (Mild form, <5 skin lesions)
  • Multibacillary (MB) Leprosy (Severe form, >5 skin lesions, positive skin smear test)

A. Paucibacillary (PB) Leprosy Treatment

DurationDrugs Used
6 monthsRifampin (600 mg once monthly) + Dapsone (100 mg daily)

B. Multibacillary (MB) Leprosy Treatment

DurationDrugs Used
12 monthsRifampin (600 mg once monthly) + Dapsone (100 mg daily) + Clofazimine (300 mg once monthly + 50 mg daily)

📌 Key Points:

  • MDT is free worldwide under the WHO Leprosy Control Program.
  • Treatment is continued until clinical cure and skin smear negativity.
  • Rifampin is the most bactericidal drug in leprosy treatment.

4. Side Effects & Adverse Reactions of Anti-Leprosy Drugs

DrugMajor Side Effects
DapsoneHemolysis in G6PD deficiency, Methemoglobinemia, Skin rash
RifampinHepatitis, Orange-colored urine & sweat, Flu-like syndrome
ClofazimineRed-black skin discoloration, GI disturbance
MinocyclinePhotosensitivity, Dizziness
OfloxacinTendon rupture, QT prolongation
ThalidomideTeratogenicity, Peripheral neuropathy

📌 Key Considerations:

  • Before starting Dapsone, check for G6PD deficiency (to prevent hemolysis).
  • Rifampin can stain contact lenses and bodily fluids orange.
  • Clofazimine causes skin pigmentation, which is reversible.

5. Leprosy Reactions (Immune Complications of Leprosy)

Leprosy patients can develop immune-mediated reactions during treatment.

A. Type 1 Reaction (Reversal Reaction)

🔹 Cause: Increased cell-mediated immunity against M. leprae
🔹 Symptoms: Red, swollen skin lesions, nerve pain, sensory loss
🔹 Treatment: Prednisolone (Corticosteroids)

B. Type 2 Reaction (Erythema Nodosum Leprosum – ENL)

🔹 Cause: Immune complex-mediated hypersensitivity
🔹 Symptoms: Painful red nodules, fever, joint pain, neuritis
🔹 Treatment: Thalidomide (Preferred), Corticosteroids

📌 Key Point: Thalidomide is highly effective for Type 2 reactions but should never be given in pregnancy.


6. Diagnosis of Leprosy

TestPurpose
Skin Smear TestIdentifies M. leprae under a microscope
Lepromin TestDifferentiates Tuberculoid & Lepromatous Leprosy
Skin BiopsyConfirms histological changes
Nerve ExaminationAssesses sensory loss & thickened nerves

📌 Lepromin Test is only used for classification, not for diagnosis.


7. Drug Interactions

Interacting DrugEffect
Rifampin + WarfarinDecreases Warfarin levels (increases clot risk)
Rifampin + Oral ContraceptivesReduces contraceptive effectiveness (Use alternative contraception)
Dapsone + ProbenecidIncreases Dapsone toxicity
Clofazimine + AntacidsReduces Clofazimine absorption

📌 Note: Patients on Rifampin should be advised to use alternative contraceptive methods.


8. Role of Nurse in Leprosy Treatment

A. Pre-Administration Assessment

  • Assess nerve function before starting treatment.
  • Check for signs of G6PD deficiency before Dapsone use.
  • Monitor liver function (ALT, AST) in patients on Rifampin.
  • Check skin condition and sensory loss for leprosy reactions.

B. Administration Considerations

  • Dapsone and Clofazimine are given daily, but Rifampin is given once a month.
  • Clofazimine should be taken with food to reduce GI upset.
  • Monitor for orange-colored urine with Rifampin (harmless side effect).
  • Avoid alcohol during treatment (reduces liver toxicity risk).

C. Monitoring During Treatment

  • Watch for signs of leprosy reactions (pain, swelling, nerve damage).
  • Monitor blood counts for Dapsone-induced anemia.
  • Assess vision regularly in patients on Clofazimine (skin pigmentation).
  • Check for signs of peripheral neuropathy in Thalidomide users.

D. Patient Education

  • Complete the full MDT course (prevents relapse & resistance).
  • Expect orange-colored urine with Rifampin (normal side effect).
  • Use sunscreen if taking Minocycline (risk of photosensitivity).
  • Pregnant women should avoid Thalidomide (severe birth defects).
  • Report any nerve pain, skin rash, or fever immediately.

9. Leprosy Prevention & Control

  • Early diagnosis and MDT to prevent transmission.
  • BCG vaccine provides some protection against leprosy.
  • Contact tracing and prophylactic treatment in high-risk individuals.
  • Community awareness programs to reduce social stigma.

Antimalarial Drugs:

1. Introduction

Malaria is a life-threatening protozoal disease caused by Plasmodium species and transmitted by Anopheles mosquitoes. The most common types of malaria include:

🔹 Plasmodium falciparum – Severe malaria (Cerebral malaria, Multi-organ failure)
🔹 Plasmodium vivax – Relapsing malaria (Liver stage hypnozoites)
🔹 Plasmodium ovale – Rare, similar to P. vivax
🔹 Plasmodium malariae – Chronic, mild malaria
🔹 Plasmodium knowlesi – Zoonotic malaria (fast replication)

📌 Key Point: P. vivax and P. ovale can remain dormant in the liver, requiring special treatment to prevent relapse.


2. Classification of Antimalarial Drugs

Antimalarial drugs act on different stages of the malaria parasite’s lifecycle. They are classified as:

A. Blood Schizonticides (Kill Asexual Blood Stages)

DrugMechanism of ActionCommon Uses
ChloroquineInhibits heme polymerization, causing parasite deathUncomplicated P. vivax, P. ovale, P. malariae
Quinine, QuinidineInhibits DNA synthesisSevere P. falciparum malaria
MefloquineInhibits heme metabolismChloroquine-resistant malaria
Artemisinin-Based Combination Therapy (ACT)Generates free radicalsP. falciparum (First-line treatment)

📌 First-line therapy for P. falciparum is ACT (Artemisinin-Based Combination Therapy).


B. Tissue Schizonticides (Kill Liver Stages)

DrugMechanism of ActionCommon Uses
PrimaquineDestroys hypnozoites in the liverP. vivax & P. ovale (Prevents relapse)
TafenoquineLong-acting hypnozoiticideRelapsing P. vivax malaria

📌 Primaquine & Tafenoquine are the only drugs that prevent relapse in P. vivax and P. ovale malaria.


C. Gametocidal Drugs (Kill Transmission Stages)

DrugMechanism of ActionCommon Uses
PrimaquineDestroys gametocytesPrevents malaria transmission
Artemisinin-Based Combination Therapy (ACT)Kills gametocytesP. falciparum

📌 Primaquine is the only drug that kills P. falciparum gametocytes, reducing transmission.


D. Antimalarial Prophylaxis (Preventive Drugs)

DrugUse
ChloroquineUsed in areas with chloroquine-sensitive malaria
MefloquineUsed in areas with chloroquine-resistant P. falciparum
DoxycyclineUsed as an alternative for short-term travelers
Atovaquone-Proguanil (Malarone)Used for high-risk travelers

📌 Travelers to malaria-endemic areas should start prophylaxis before exposure and continue after returning.


3. WHO-Recommended Treatment of Malaria

A. Uncomplicated Malaria

Plasmodium SpeciesFirst-Line Treatment
P. falciparum (Drug-resistant)ACT (Artemether-Lumefantrine, Artesunate + Mefloquine, Artesunate + Amodiaquine)
P. vivax & P. ovaleChloroquine + Primaquine (for hypnozoites)
P. malariae & P. knowlesiChloroquine

B. Severe Malaria (P. falciparum)

Treatment RegimenDrugs Used
IV Therapy (First 24 hrs)IV Artesunate or IV Quinine
Follow-Up (Oral Therapy)ACT (Artemether-Lumefantrine) for 3 days

📌 Severe malaria should be treated with IV Artesunate as soon as possible.


4. Side Effects & Adverse Reactions of Antimalarial Drugs

DrugMajor Side Effects
ChloroquineRetinopathy, Hearing loss, QT prolongation
Quinine/QuinidineCinchonism (Tinnitus, Dizziness, Nausea), Hypoglycemia
MefloquineNeuropsychiatric effects (Hallucinations, Depression, Anxiety)
Artemisinin-Based DrugsHemolysis in G6PD deficiency, Nausea
PrimaquineHemolysis in G6PD deficiency
Atovaquone-Proguanil (Malarone)Nausea, Liver dysfunction
DoxycyclinePhotosensitivity, Esophagitis

📌 Before prescribing Primaquine, always check for G6PD deficiency to prevent hemolysis.


5. Drug Interactions

Interacting DrugEffect
Chloroquine + DigoxinIncreases Digoxin toxicity
Quinine + WarfarinIncreases bleeding risk
Mefloquine + SSRIsIncreases risk of psychiatric effects
Doxycycline + AntacidsDecreased absorption of Doxycycline

📌 Patients taking psychiatric medications should avoid Mefloquine due to neuropsychiatric effects.


6. Role of Nurse in Malaria Treatment

A. Pre-Administration Assessment

  • Assess for G6PD deficiency before prescribing Primaquine.
  • Monitor liver function in patients taking Artemisinin-based drugs.
  • Check ECG in patients receiving Chloroquine or Quinine (QT prolongation risk).
  • Assess for psychiatric history before prescribing Mefloquine.

B. Administration Considerations

  • Chloroquine should be taken with food to reduce GI upset.
  • IV Artesunate must be given slowly (risk of hemolysis).
  • Quinine infusion should be monitored for hypoglycemia (stimulates insulin release).
  • Doxycycline should be taken with a full glass of water to prevent esophagitis.

C. Monitoring During Treatment

  • Monitor blood glucose in patients on IV Quinine (risk of hypoglycemia).
  • Watch for signs of neuropsychiatric effects in Mefloquine users.
  • Assess vision regularly in patients on long-term Chloroquine therapy.
  • Monitor for jaundice and dark urine (possible drug-induced hemolysis).

D. Patient Education

  • Complete the full course of treatment to prevent resistance.
  • Use mosquito nets and repellents to avoid reinfection.
  • Take antimalarial prophylaxis before, during, and after travel.
  • Avoid alcohol with antimalarial drugs (reduces liver toxicity risk).

7. Malaria Prevention & Control

  • Vector Control: Insecticide-treated bed nets (ITNs), Indoor residual spraying (IRS).
  • Chemoprophylaxis: For travelers to endemic areas.
  • Prompt Diagnosis & Treatment: Reduces transmission and complications.
  • Vaccination: The RTS,S/AS01 (Mosquirix) vaccine is approved for P. falciparum malaria.

📌 The RTS,S vaccine is now included in WHO’s malaria control strategies for children in endemic regions.

Antiretroviral Drugs:

Antiretroviral drugs (ARVs) are used to manage and treat HIV/AIDS by suppressing the replication of the virus in the body. They are classified into different groups based on their mechanism of action.


1. Composition and Classification

ARVs are categorized into six major classes:

  1. Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTIs)
    • Examples: Zidovudine (AZT), Lamivudine (3TC), Abacavir (ABC), Tenofovir (TDF), Emtricitabine (FTC)
  2. Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
    • Examples: Efavirenz (EFV), Nevirapine (NVP), Etravirine (ETR), Rilpivirine (RPV)
  3. Protease Inhibitors (PIs)
    • Examples: Lopinavir/Ritonavir (LPV/r), Atazanavir (ATV), Darunavir (DRV)
  4. Integrase Strand Transfer Inhibitors (INSTIs)
    • Examples: Raltegravir (RAL), Dolutegravir (DTG), Elvitegravir (EVG)
  5. Entry Inhibitors (Fusion Inhibitors)
    • Examples: Enfuvirtide (T-20)
  6. CCR5 Antagonists
    • Example: Maraviroc (MVC)

2. Action (Mechanism of Action)

ARVs work by inhibiting different stages of the HIV life cycle:

  • NRTIs & NNRTIs: Block the reverse transcriptase enzyme, preventing viral RNA from converting into DNA.
  • PIs: Inhibit the protease enzyme, preventing the maturation of viral proteins.
  • INSTIs: Block the integration of viral DNA into the host genome.
  • Entry & Fusion Inhibitors: Prevent the virus from entering the host cells.

3. Dosage and Route of Administration

  • NRTIs (e.g., Zidovudine): 300 mg orally twice daily
  • NNRTIs (e.g., Efavirenz): 600 mg orally once daily at bedtime
  • PIs (e.g., Lopinavir/Ritonavir): 400/100 mg orally twice daily
  • INSTIs (e.g., Dolutegravir): 50 mg orally once daily
  • Fusion Inhibitors (e.g., Enfuvirtide): 90 mg subcutaneously twice daily

Routes: Oral (most drugs), Subcutaneous (Enfuvirtide), Intravenous (for some emergency cases)


4. Indications

  • Treatment of HIV/AIDS (Combination Therapy – ART)
  • Pre-Exposure Prophylaxis (PrEP) (e.g., Tenofovir + Emtricitabine)
  • Post-Exposure Prophylaxis (PEP) (e.g., Tenofovir + Lamivudine + Dolutegravir)
  • Prevention of Mother-to-Child Transmission (PMTCT) (e.g., Zidovudine during pregnancy)

5. Contraindications

  • Severe hepatic or renal impairment
  • Hypersensitivity to the drug (e.g., Abacavir hypersensitivity reaction)
  • Pregnancy Category C or D drugs (e.g., Efavirenz in the first trimester)
  • Co-infection with tuberculosis (Caution with Rifampicin interactions)

6. Drug Interactions

  • Efavirenz: Reduces the effectiveness of oral contraceptives.
  • Ritonavir (PI Booster): Inhibits CYP3A4, increasing the levels of other drugs.
  • Tenofovir + Didanosine: Increased risk of toxicity.
  • Dolutegravir + Metformin: Increased Metformin levels (dose adjustment needed).
  • Nevirapine + Rifampicin: Decreased Nevirapine effectiveness.

7. Side Effects

Drug ClassCommon Side Effects
NRTIsNausea, headache, fatigue, bone marrow suppression (Zidovudine)
NNRTIsRash, hepatotoxicity, CNS effects (Efavirenz – vivid dreams, dizziness)
PIsLipodystrophy, hyperglycemia, diarrhea, liver toxicity
INSTIsInsomnia, headache, weight gain
Entry InhibitorsInjection site reactions, hypersensitivity

8. Adverse Effects & Toxicity

  • Zidovudine (AZT)Bone marrow suppression → Anemia, neutropenia
  • Abacavir (ABC)Hypersensitivity reaction → Fever, rash, GI distress (HLA-B*5701 testing needed)
  • Efavirenz (EFV)Neuropsychiatric symptoms → Nightmares, depression, suicidal ideation
  • Lopinavir/Ritonavir (LPV/r)Pancreatitis, diabetes risk
  • Tenofovir (TDF)Renal toxicity, osteoporosis

9. Role of Nurse in Antiretroviral Therapy

1. Patient Assessment

  • Assess HIV status, CD4 count, and viral load before starting therapy.
  • Monitor for hepatic and renal function before prescribing ARVs.
  • Check for drug interactions (e.g., Rifampicin, oral contraceptives).

2. Patient Education

  • Educate on adherence: ARVs must be taken daily to prevent drug resistance.
  • Inform about side effects and when to seek medical attention.
  • Advise on safe sexual practices to prevent HIV transmission.

3. Monitoring & Nursing Care

  • Regularly monitor CD4 count and viral load.
  • Check for signs of toxicity (e.g., renal function tests for Tenofovir).
  • Manage side effects (e.g., providing antiemetics for nausea).

4. Special Considerations

  • Pregnancy: Ensure proper PMTCT protocol (Zidovudine).
  • Pediatric Care: Adjust doses according to weight.
  • Elderly Patients: Monitor closely for metabolic complications (diabetes, osteoporosis).

Antiviral Agents:

Antiviral agents are medications used to treat viral infections by inhibiting virus replication and reducing the severity of illness. Unlike antibiotics, which target bacteria, antivirals specifically interfere with viral replication processes.


1. Classification and Composition

Antiviral agents are classified based on their mechanism of action:

A. Anti-HIV Drugs (Antiretroviral Therapy – ART)

  • Nucleoside Reverse Transcriptase Inhibitors (NRTIs) – Zidovudine (AZT), Lamivudine (3TC)
  • Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) – Efavirenz (EFV), Nevirapine (NVP)
  • Protease Inhibitors (PIs) – Lopinavir/Ritonavir (LPV/r), Atazanavir (ATV)
  • Integrase Inhibitors (INSTIs) – Dolutegravir (DTG), Raltegravir (RAL)
  • Entry Inhibitors – Maraviroc (MVC), Enfuvirtide (T-20)

B. Anti-Influenza Drugs

  • Neuraminidase Inhibitors – Oseltamivir (Tamiflu), Zanamivir
  • M2 Ion Channel Blockers – Amantadine, Rimantadine

C. Anti-Hepatitis Drugs

  • Hepatitis B (HBV) Drugs – Tenofovir, Entecavir, Lamivudine
  • Hepatitis C (HCV) Drugs – Sofosbuvir, Ledipasvir, Ribavirin, Daclatasvir

D. Anti-Herpes Drugs

  • Herpes Simplex Virus (HSV) & Varicella-Zoster Virus (VZV) – Acyclovir, Valacyclovir, Famciclovir
  • Cytomegalovirus (CMV) – Ganciclovir, Foscarnet, Cidofovir

E. Other Antiviral Drugs

  • Ebola Virus – Remdesivir
  • RSV (Respiratory Syncytial Virus) – Ribavirin, Palivizumab

2. Mechanism of Action

Antiviral agents work by targeting different stages of viral replication:

  • Entry Inhibitors – Prevent viral entry into host cells (Maraviroc)
  • Reverse Transcriptase Inhibitors – Block viral RNA-to-DNA conversion (Tenofovir, Lamivudine)
  • Protease Inhibitors – Prevent viral protein maturation (Atazanavir, Ritonavir)
  • Neuraminidase Inhibitors – Block viral release from host cells (Oseltamivir)
  • Nucleoside Analogues – Prevent viral DNA synthesis (Acyclovir, Ganciclovir)

3. Dosage and Route of Administration

DrugDoseRoute
Acyclovir400 mg 3 times/day (HSV)Oral/IV
Oseltamivir75 mg twice/day (Influenza)Oral
Lamivudine100 mg once/day (Hepatitis B)Oral
Sofosbuvir400 mg once/day (Hepatitis C)Oral
Zidovudine300 mg twice/day (HIV)Oral/IV
Remdesivir200 mg IV on Day 1, then 100 mg/dayIV

4. Indications

  • HIV/AIDS – Antiretroviral Therapy (ART)
  • Influenza – Oseltamivir (within 48 hours of symptom onset)
  • Hepatitis B & C – Chronic viral hepatitis management
  • Herpes Infections – Herpes simplex, shingles, CMV infections
  • COVID-19 & Ebola – Remdesivir for severe cases

5. Contraindications

  • Severe renal or liver impairment (Tenofovir, Ribavirin)
  • Pregnancy caution (Ribavirin is teratogenic)
  • Hypersensitivity to the drug (Acyclovir, Efavirenz)
  • Cardiac conditions (Some hepatitis drugs affect heart rhythms)

6. Drug Interactions

  • Oseltamivir + Live Influenza Vaccine → Reduced vaccine efficacy
  • Sofosbuvir + Amiodarone → Risk of fatal heart block
  • Protease Inhibitors + Rifampicin → Reduces antiviral effectiveness
  • Acyclovir + Nephrotoxic Drugs → Increased risk of kidney damage

7. Side Effects

Drug ClassCommon Side Effects
NRTIs (HIV)Nausea, headache, anemia (Zidovudine)
NNRTIs (HIV)Rash, dizziness, hepatotoxicity
PIs (HIV)Lipodystrophy, diabetes risk
Neuraminidase Inhibitors (Flu)Nausea, vomiting
Nucleoside Analogues (Herpes, CMV)Nephrotoxicity (Acyclovir, Ganciclovir)

8. Adverse Effects & Toxicity

  • Zidovudine → Bone marrow suppression (anemia, neutropenia)
  • Ribavirin → Hemolytic anemia, fetal toxicity
  • Acyclovir (IV use) → Nephrotoxicity, neurotoxicity
  • Remdesivir → Liver enzyme elevation, hypotension

9. Role of Nurse in Antiviral Therapy

1. Patient Assessment

  • Check renal and liver function before administering drugs.
  • Monitor CD4 count and viral load for HIV patients.
  • Assess symptom progression (Influenza, Herpes, Hepatitis).

2. Patient Education

  • Strict adherence to treatment to prevent resistance.
  • Hydration advice for nephrotoxic drugs like Acyclovir.
  • Oseltamivir should be taken within 48 hours of flu symptoms.

3. Monitoring & Nursing Care

  • Watch for allergic reactions (rash, anaphylaxis).
  • Monitor for organ toxicity (renal function for Acyclovir, liver function for Sofosbuvir).
  • Encourage vaccination for viral prevention.

4. Special Considerations

  • Pregnant women with HIV → Zidovudine to prevent mother-to-child transmission.
  • Immunocompromised patients → Need early intervention for viral infections.
  • Elderly patients → Higher risk of adverse effects (renal impairment).

Antihelminthic Drugs: Comprehensive Overview

1. Introduction

Antihelminthic drugs are used to treat parasitic worm infections caused by different types of helminths, including nematodes (roundworms), trematodes (flukes), and cestodes (tapeworms). These drugs work by targeting the metabolism, neuromuscular system, or other vital functions of the parasite, leading to its paralysis or death.


2. Classification and Composition

Antihelminthic drugs are classified based on their action against specific worm types:

ClassExamplesEffective Against
BenzimidazolesAlbendazole, MebendazoleNematodes (roundworms), Cestodes (tapeworms)
Macrocyclic LactonesIvermectinNematodes (strongyloides, filarial worms)
TetrahydropyrimidinesPyrantel PamoateNematodes (hookworms, pinworms)
Piperazine DerivativesPiperazineAscaris (roundworms)
Isoquinoline DerivativesPraziquantelTrematodes (flukes), Cestodes (tapeworms)
SalicylanilidesNiclosamideCestodes (tapeworms)

3. Mechanism of Action

Different antihelminthic drugs work through various mechanisms:

  • Albendazole, Mebendazole: Inhibit microtubule formation, leading to paralysis and death of worms.
  • Ivermectin: Enhances GABA neurotransmission, leading to paralysis of nematodes.
  • Pyrantel Pamoate: Causes neuromuscular blockade, leading to paralysis of worms.
  • Praziquantel: Increases calcium permeability, leading to spastic paralysis and death of flukes and tapeworms.
  • Niclosamide: Inhibits glucose uptake, leading to tapeworm death.

4. Dosage and Route of Administration

DrugDoseRoute
Albendazole400 mg single dose (Ascariasis, Hookworm)Oral
Mebendazole100 mg twice/day for 3 daysOral
Ivermectin200 mcg/kg single dose (Strongyloidiasis)Oral
Praziquantel40 mg/kg single dose (Schistosomiasis)Oral
Niclosamide2 g single dose (Tapeworms)Oral
Pyrantel Pamoate11 mg/kg single dose (Pinworms)Oral

Most antihelminthics are given orally.
For severe infections, repeat doses may be needed.


5. Indications

Antihelminthics are used for treating various parasitic infections:

A. Nematode Infections (Roundworms)

  • Ascariasis (Ascaris lumbricoides) – Albendazole, Mebendazole, Pyrantel
  • Hookworm (Ancylostoma, Necator) – Albendazole, Mebendazole
  • Strongyloidiasis (Strongyloides stercoralis) – Ivermectin
  • Filariasis (Wuchereria bancrofti) – Diethylcarbamazine (DEC), Ivermectin
  • Enterobiasis (Pinworms – Enterobius vermicularis) – Pyrantel Pamoate, Albendazole

B. Cestode Infections (Tapeworms)

  • Taeniasis (Tapeworms – Taenia saginata, Taenia solium) – Niclosamide, Praziquantel
  • Cysticercosis (Pork Tapeworm Larvae – Neurocysticercosis) – Albendazole, Praziquantel
  • Echinococcosis (Hydatid Cysts – Echinococcus granulosus) – Albendazole

C. Trematode Infections (Flukes)

  • Schistosomiasis (Blood flukes) – Praziquantel
  • Liver Flukes (Fasciola hepatica, Clonorchis sinensis) – Triclabendazole, Praziquantel

6. Contraindications

  • Pregnancy (Avoid Albendazole, Mebendazole in the first trimester)
  • Severe liver disease (Praziquantel, Albendazole can cause hepatotoxicity)
  • CNS involvement (Neurocysticercosis) – Can cause inflammation (Steroids may be needed)
  • Hypersensitivity to drug components

7. Drug Interactions

  • Albendazole + Dexamethasone → Increases Albendazole levels
  • Praziquantel + Rifampicin → Decreased effectiveness of Praziquantel
  • Ivermectin + Benzodiazepines → Increased risk of CNS depression
  • Mebendazole + Metronidazole → Risk of Stevens-Johnson syndrome

8. Side Effects

Drug ClassCommon Side Effects
BenzimidazolesNausea, liver toxicity, bone marrow suppression
IvermectinItching, dizziness, hypotension
Pyrantel PamoateGI upset, headache
PraziquantelDrowsiness, abdominal pain, nausea
NiclosamideGI distress, fatigue

9. Adverse Effects & Toxicity

  • Albendazole → Hepatotoxicity, bone marrow suppression (monitor liver function)
  • Ivermectin → Severe neurotoxicity in high doses
  • Praziquantel → Seizures in neurocysticercosis (give corticosteroids)
  • Niclosamide → Allergic reactions, dizziness

10. Role of Nurse in Antihelminthic Therapy

1. Patient Assessment

  • Assess symptoms of worm infestation (abdominal pain, diarrhea, anemia).
  • Check for previous medication use to prevent interactions.
  • Monitor pregnancy status (avoid Albendazole in 1st trimester).

2. Patient Education

  • Take medication after food to improve absorption.
  • Hygiene measures: Wash hands, avoid undercooked meat.
  • Avoid alcohol with Albendazole, Praziquantel.
  • Family treatment: Treat all family members for pinworms.

3. Monitoring & Nursing Care

  • Monitor liver function (Albendazole, Praziquantel).
  • Check for side effects (dizziness, nausea, GI upset).
  • Encourage follow-up stool examination to confirm cure.

4. Special Considerations

  • Children: Pyrantel Pamoate is preferred for pinworms.
  • Elderly patients: Watch for drug-induced dizziness (Praziquantel).
  • Neurocysticercosis: Give steroids to reduce brain inflammation.

Anti-Scabies Agents: Comprehensive Overview

1. Introduction

Scabies is a contagious skin infestation caused by the Sarcoptes scabiei mite. It spreads through direct skin contact and infested clothing, bedding, or furniture. Anti-scabies agents are used to kill the mites and relieve symptoms like itching and rash.


2. Classification of Anti-Scabies Agents

Anti-scabies drugs are classified based on their mode of action:

ClassExamplesMechanism of Action
Topical ScabicidesPermethrin 5% creamParalyzes and kills mites by disrupting their nervous system
Lindane 1% lotionNeurotoxin that kills mites but can be toxic to humans
Benzyl Benzoate (10–25%)Suffocates mites and destroys their cell membranes
Sulfur ointment (5–10%)Toxic to mites, safe for infants and pregnant women
Crotamiton 10% (Eurax)Kills mites and relieves itching
Oral ScabicidesIvermectin (200 mcg/kg)Paralyzes and kills mites via GABA-mediated action

Topical agents are first-line treatment.
Oral Ivermectin is used in severe or resistant cases.


3. Mechanism of Action

Anti-scabies drugs work by:

  • Neurotoxicity (Permethrin, Lindane, Ivermectin) – Paralysis and death of mites.
  • Membrane Disruption (Benzyl Benzoate) – Destroys mite cells.
  • Suffocation & Poisoning (Sulfur ointment, Crotamiton) – Kills mites slowly.

4. Dosage and Route of Administration

DrugDosage & FrequencyRoute
Permethrin 5% creamApply overnight, wash after 8-12 hours, repeat after 7 daysTopical
Lindane 1% lotionApply for 8 hours, wash off, (Avoid in infants, pregnant women, epilepsy)Topical
Benzyl Benzoate 10-25%Apply for 24 hours, repeat if neededTopical
Sulfur ointment 5-10%Apply for 3 nights, leave overnightTopical
Crotamiton 10%Apply daily for 5 daysTopical
Ivermectin (200 mcg/kg)Single oral dose, repeat after 7-14 daysOral

Permethrin 5% is the preferred treatment.
Ivermectin is used for crusted scabies or widespread outbreaks.
Benzyl Benzoate and Sulfur are economical options.


5. Indications

  • Classic Scabies – Permethrin 5% cream (first-line)
  • Crusted (Norwegian) Scabies – Ivermectin + topical therapy
  • Infants & Pregnant Women – Sulfur ointment or Crotamiton
  • Lindane is a second-line drug due to neurotoxicity risks

6. Contraindications

DrugContraindications
LindaneAvoid in pregnancy, breastfeeding, infants, seizure disorders
IvermectinAvoid in children under 15 kg, pregnant women
Benzyl BenzoateCan cause severe skin irritation in young children
Sulfur ointmentMessy, unpleasant odor (but safe for infants & pregnancy)

7. Drug Interactions

  • Lindane + CNS Depressants → Increased risk of seizures
  • Ivermectin + Warfarin → Increased bleeding risk
  • Topical Corticosteroids → Reduce efficacy of anti-scabies drugs

8. Side Effects

DrugCommon Side Effects
PermethrinMild burning, itching, redness
LindaneNeurotoxicity (dizziness, seizures)
Benzyl BenzoateSevere skin irritation, burning sensation
SulfurSkin dryness, bad odor
IvermectinNausea, dizziness, headache

Lindane is no longer widely used due to toxicity risks.
Ivermectin is well tolerated but should be avoided in pregnancy.


9. Adverse Effects & Toxicity

  • Lindane overdoseSeizures, neurotoxicity (especially in infants)
  • Ivermectin high doseHypotension, dizziness
  • Benzyl BenzoateSevere burning sensation
  • SulfurSkin dryness, irritation (but safe overall)

10. Role of Nurse in Scabies Treatment

1. Patient Assessment

  • Check skin lesions, itching, family history of scabies.
  • Ask about pregnancy, children, or seizure disorders (avoid Lindane).

2. Patient Education

  • Apply topical creams from neck to toe (Permethrin, Benzyl Benzoate).
  • Wash off after 8-12 hours (Permethrin) or 24 hours (Benzyl Benzoate).
  • Treat all close contacts even if they have no symptoms.
  • Wash clothes, bedding in hot water to prevent reinfection.

3. Monitoring & Nursing Care

  • Watch for adverse effects (Lindane toxicity, Ivermectin side effects).
  • Check skin improvement within 7-14 days.
  • Prevent reinfection by encouraging hygiene practices.

4. Special Considerations

  • Infants: Use Sulfur ointment or Crotamiton (safe alternatives).
  • Pregnant women: Avoid Lindane, prefer Permethrin or Sulfur.
  • Crusted scabies: Requires oral Ivermectin + topical agents.

Antifungal Agents:

1. Introduction

Antifungal agents are medications used to treat fungal infections affecting the skin, nails, mucous membranes, and internal organs. These infections are caused by yeasts, molds, and dimorphic fungi and can range from superficial to systemic mycoses.


2. Classification of Antifungal Agents

Antifungal drugs are classified based on their mechanism of action and fungal targets:

ClassExamplesMechanism of ActionIndications
PolyenesAmphotericin B, NystatinBinds to ergosterol, forming pores in fungal cell membraneSystemic mycoses (Amphotericin B), Oral and vaginal candidiasis (Nystatin)
AzolesFluconazole, Itraconazole, Ketoconazole, ClotrimazoleInhibit ergosterol synthesis, disrupting fungal cell membraneCandidiasis, Dermatophytosis, Systemic mycoses
EchinocandinsCaspofungin, Micafungin, AnidulafunginInhibit β-glucan synthesis, affecting fungal cell wallSystemic candidiasis, Aspergillosis
AllylaminesTerbinafine, NaftifineInhibit squalene epoxidase, preventing ergosterol synthesisDermatophytosis, Onychomycosis
Pyrimidine AnalogFlucytosineInhibits fungal DNA & RNA synthesisCryptococcal meningitis (with Amphotericin B)
GriseofulvinGriseofulvinInhibits microtubule function, preventing fungal mitosisTinea infections (scalp, nails, skin)

Topical agents are used for superficial infections.
Systemic antifungals are required for deep-seated infections.


3. Mechanism of Action

Different antifungals target fungal cell structures:

  • Polyenes (Amphotericin B, Nystatin) → Disrupt cell membrane by binding to ergosterol.
  • Azoles (Fluconazole, Itraconazole) → Inhibit ergosterol synthesis.
  • Echinocandins (Caspofungin) → Inhibit cell wall synthesis.
  • Allylamines (Terbinafine) → Block squalene epoxidase, disrupting ergosterol formation.
  • Flucytosine → Inhibits DNA & RNA synthesis.
  • Griseofulvin → Disrupts mitosis in dermatophytes.

4. Dosage and Route of Administration

DrugDoseRoute
Fluconazole150 mg once (Vaginal Candidiasis)Oral
Itraconazole200 mg/day (Systemic Mycoses)Oral
Amphotericin B0.7-1 mg/kg/dayIV
Caspofungin50 mg IV dailyIV
Terbinafine250 mg/day (Onychomycosis)Oral
NystatinApply 2-3 times/day (Oral Thrush)Topical
Griseofulvin500 mg/day (Tinea Capitis)Oral

Oral and IV drugs are for deep or systemic fungal infections.
Topical agents are used for skin, nail, and mucosal infections.


5. Indications

A. Superficial Fungal Infections

  • Candidiasis (Oral, Vaginal, Skin) – Fluconazole, Nystatin, Clotrimazole
  • Dermatophytosis (Ringworm, Athlete’s Foot, Jock Itch, Nail Fungus) – Terbinafine, Griseofulvin
  • Tinea Infections (Scalp, Nails, Body, Feet) – Griseofulvin, Terbinafine, Clotrimazole

B. Systemic & Opportunistic Infections

  • Cryptococcal Meningitis – Amphotericin B + Flucytosine
  • Systemic Candidiasis – Fluconazole, Caspofungin
  • Aspergillosis – Itraconazole, Voriconazole
  • Histoplasmosis, Blastomycosis – Itraconazole, Amphotericin B

6. Contraindications

DrugContraindications
Amphotericin BKidney disease (Nephrotoxicity)
Azoles (Fluconazole, Itraconazole)Liver disease, Pregnancy
Echinocandins (Caspofungin)Hypersensitivity
TerbinafineLiver failure
GriseofulvinPregnancy (Teratogenic)

Avoid Fluconazole in pregnancy unless necessary.
Monitor liver and kidney function with systemic antifungals.


7. Drug Interactions

  • Fluconazole + Warfarin → Increased bleeding risk
  • Itraconazole + Statins → Rhabdomyolysis risk
  • Amphotericin B + Nephrotoxic Drugs → Kidney damage
  • Echinocandins + Cyclosporine → Liver toxicity

8. Side Effects

Drug ClassCommon Side Effects
Polyenes (Amphotericin B)Fever, chills, kidney toxicity
Azoles (Fluconazole, Itraconazole)Nausea, liver toxicity, hormonal imbalance
Echinocandins (Caspofungin)Rash, fever, liver enzyme elevation
Allylamines (Terbinafine)GI upset, headache, liver toxicity
GriseofulvinDizziness, photosensitivity

Amphotericin B is highly nephrotoxic (kidney damage risk).
Fluconazole and Itraconazole can cause liver damage.
Griseofulvin should be taken with fatty foods for better absorption.


9. Adverse Effects & Toxicity

  • Amphotericin BSevere nephrotoxicity, infusion reactions (fever, chills)
  • Fluconazole & ItraconazoleHepatotoxicity, prolonged QT interval (cardiac risk)
  • CaspofunginLiver toxicity, allergic reactions
  • TerbinafineLiver failure (rare but serious)
  • GriseofulvinNeurological symptoms, photosensitivity

Amphotericin B requires kidney function monitoring.
Azoles require liver function monitoring.


10. Role of Nurse in Antifungal Therapy

1. Patient Assessment

  • Assess symptoms (rash, oral thrush, fever, systemic symptoms).
  • Check for liver and kidney disease before prescribing antifungals.
  • Monitor drug interactions (especially with Fluconazole, Itraconazole).

2. Patient Education

  • Complete full course of antifungal treatment.
  • Avoid alcohol (increases liver toxicity).
  • Take Griseofulvin with fatty food for better absorption.
  • Use separate towels, clothing to prevent fungal spread.

3. Monitoring & Nursing Care

  • Monitor kidney function (Amphotericin B).
  • Check liver function tests (Fluconazole, Itraconazole, Terbinafine).
  • Watch for side effects (nausea, dizziness, liver dysfunction).

4. Special Considerations

  • Pregnancy: Avoid Azoles and Griseofulvin.
  • Immunocompromised patients: Use strong systemic antifungals (Echinocandins, Amphotericin B).
  • Elderly patients: Higher risk of drug interactions and liver toxicity.
Published
Categorized as BSC - SEM 3 - PHARMACOLOGY, Uncategorised