UNIT 2 Pharmacology of commonly used antiseptics and disinfectants.

Introduction to Antiseptics and Disinfectants

Antiseptics and disinfectants are chemical agents used to prevent infection by killing or inhibiting the growth of microorganisms. They play a crucial role in infection control in healthcare settings, public health, and everyday hygiene practices. While both antiseptics and disinfectants serve similar purposes, they are used in different contexts and have distinct characteristics.

Definitions

1. Antiseptics:
   • Definition: Antiseptics are chemical agents that are applied to living tissues, such as skin or mucous membranes, to kill or inhibit the growth of microorganisms. They are used to prevent infections in wounds, cuts, and during surgical procedures by reducing the microbial load on the skin.
   • Common Examples: Alcohol (e.g., isopropyl alcohol), iodine solutions (e.g., povidone-iodine), hydrogen peroxide, chlorhexidine, and triclosan.
   • Uses:
     • Preoperative skin preparation
     • Hand sanitizers
     • Wound cleaning
     • Mouthwashes
2. Disinfectants:
   • Definition: Disinfectants are chemical agents used on inanimate objects and surfaces to kill or inactivate microorganisms, including bacteria, viruses, fungi, and spores. Disinfectants are generally too harsh for use on living tissues and are primarily used for cleaning surfaces, instruments, and equipment in healthcare settings, households, and public spaces.
   • Common Examples: Bleach (sodium hypochlorite), alcohols (ethanol and isopropyl alcohol), phenols, quaternary ammonium compounds, and formaldehyde.
   • Uses:
     • Disinfecting medical instruments and equipment
     • Cleaning surfaces in hospitals, clinics, and homes
     • Sanitizing water supplies
     • Sterilizing laboratory environments

Key Differences

• Application:
  • Antiseptics: Applied to living tissues to reduce the risk of infection by killing or inhibiting the growth of pathogens.
  • Disinfectants: Applied to non-living objects and surfaces to destroy microorganisms and prevent the spread of infections.
• Potency:
  • Antiseptics: Typically less potent than disinfectants because they must be safe for use on living tissues.
  • Disinfectants: Generally stronger and more toxic than antiseptics, designed to kill microorganisms on non-living surfaces.
• Use Context:
  • Antiseptics: Used in surgical procedures, wound care, and routine hand hygiene in healthcare settings.
  • Disinfectants: Used in sterilization of surgical instruments, cleaning hospital rooms, and sanitizing public spaces.

Importance in Healthcare and Public Health

• Infection Control: Both antiseptics and disinfectants are critical in preventing the spread of infections, especially in healthcare settings where the risk of hospital-acquired infections (HAIs) is high.
• Public Health: Disinfectants play a key role in controlling the spread of infectious diseases in public spaces, particularly during outbreaks and pandemics (e.g., COVID-19).
• Surgical Safety: The use of antiseptics in preoperative skin preparation helps reduce the risk of postoperative infections.

Antiseptics and disinfectants are essential tools in the fight against infections. Understanding the difference between these agents and their appropriate use is crucial for effective infection control in both healthcare settings and everyday environments. By reducing the microbial load on living tissues and inanimate surfaces, antiseptics and disinfectants help protect public health and ensure the safety of medical procedures.

Commonly Used Antiseptics and Disinfectants:

Below is a detailed overview of some commonly used antiseptics and disinfectants, covering their composition, action, dosage, route, indications, contraindications, drug interactions, side effects, adverse effects, and toxicity.

1. Alcohols (Isopropyl Alcohol and Ethanol)

• Composition:
  • Isopropyl Alcohol: Typically used in concentrations of 70%.
  • Ethanol: Often used in concentrations of 60-90%.
• Action:
  • Alcohols denature proteins and dissolve lipids, leading to the disruption of microbial cell membranes and inactivation of enzymes.
• Dosage and Route:
  • Topical Application: Applied directly to the skin or surfaces. No specific “dose” in terms of quantity, as it is used until the area is sufficiently wetted.
  • Hand Sanitizers: Used as a hand rub in appropriate quantities (usually a small amount, rubbed until dry).
• Indications:
  • Skin antisepsis before injections, venipuncture, and minor procedures.
  • Disinfection of small surfaces and instruments.
  • Hand hygiene in healthcare settings.
• Contraindications:
  • Open wounds or damaged skin due to the potential for irritation and delay in healing.
  • Use in neonates, particularly premature infants, due to the risk of systemic absorption and toxicity.
• Drug Interactions:
  • No significant drug interactions when used topically.
• Side Effects:
  • Skin irritation, dryness, or dermatitis with repeated use.
• Adverse Effects:
  • Rarely, systemic absorption leading to alcohol toxicity, particularly in young children or large skin areas.
• Toxicity:
  • Ingestion of alcohol-based antiseptics can lead to alcohol poisoning, requiring immediate medical intervention.

2. Chlorhexidine Gluconate

• Composition:
  • Available in concentrations ranging from 0.5% to 4% in aqueous or alcoholic solutions.
• Action:
  • Chlorhexidine disrupts the cell membrane of bacteria and precipitates cellular contents, leading to cell death.
• Dosage and Route:
  • Topical: Applied directly to the skin or mucous membranes.
  • Oral Rinse: Typically used as a 0.12% solution for oral rinses.
• Indications:
  • Preoperative skin preparation.
  • Hand hygiene.
  • Treatment and prevention of gingivitis (oral rinse).
• Contraindications:
  • Hypersensitivity to chlorhexidine.
  • Use with caution in the middle ear or around the eyes due to the risk of ototoxicity and ocular irritation.
• Drug Interactions:
  • Incompatible with soaps, iodine, and anionic agents, which can reduce its effectiveness.
• Side Effects:
  • Skin irritation, allergic reactions.
  • Oral use: Can cause tooth staining and altered taste.
• Adverse Effects:
  • Rare but can include anaphylactic reactions in highly sensitive individuals.
• Toxicity:
  • Low systemic toxicity when used appropriately. However, ingestion can lead to gastrointestinal irritation and central nervous system effects.

3. Povidone-Iodine (Betadine)

• Composition:
  • A complex of iodine with povidone, usually available as a 10% solution, which releases iodine slowly.
• Action:
  • Iodine penetrates microbial cell walls and disrupts protein and nucleic acid structures, leading to microbial death.
• Dosage and Route:
  • Topical: Applied directly to the skin or mucous membranes, often used in full-strength or diluted forms for wound care and preoperative skin preparation.
• Indications:
  • Skin antisepsis before surgery.
  • Treatment of minor wounds, cuts, and burns.
  • Disinfection of mucous membranes (e.g., vaginal douche).
• Contraindications:
  • Hypersensitivity to iodine or povidone-iodine.
  • Thyroid disorders, as iodine can be absorbed and affect thyroid function.
  • Avoid use in neonates due to the risk of iodine absorption and thyroid dysfunction.
• Drug Interactions:
  • Reduced efficacy when used with hydrogen peroxide, silver, or taurolidine.
• Side Effects:
  • Local irritation, skin discoloration.
  • Rare allergic reactions.
• Adverse Effects:
  • Prolonged use can lead to systemic iodine absorption, potentially affecting thyroid function.
• Toxicity:
  • Ingestion can lead to iodine toxicity, manifesting as abdominal pain, vomiting, diarrhea, and metabolic disturbances.

4. Hydrogen Peroxide

• Composition:
  • Available in concentrations ranging from 3% to 6% for antiseptic use.
• Action:
  • Hydrogen peroxide produces free radicals that attack cell components, including lipids, proteins, and DNA, leading to microbial cell death.
• Dosage and Route:
  • Topical: Applied to wounds or surfaces; typically used as a 3% solution.
  • Oral: Can be used as a diluted solution (1.5%) for oral rinses.
• Indications:
  • Cleaning and debriding wounds.
  • Oral hygiene (as a mouth rinse).
  • Disinfection of small surfaces.
• Contraindications:
  • Hypersensitivity to hydrogen peroxide.
  • Do not use in closed body cavities or large wounds due to the risk of gas embolism.
• Drug Interactions:
  • Reduced efficacy when combined with substances like iodine or certain metals.
• Side Effects:
  • Local irritation, stinging, or burning sensation.
  • Temporary whitening of the skin.
• Adverse Effects:
  • Overuse can lead to tissue damage due to its oxidative effects.
  • Rarely, gas embolism if applied to deep or large wounds.
• Toxicity:
  • Ingestion of concentrated solutions can lead to severe gastrointestinal irritation, vomiting, and the potential release of oxygen leading to gas embolism.

5. Sodium Hypochlorite (Bleach)

• Composition:
  • Typically available as a 5-6% solution for disinfection.
• Action:
  • Sodium hypochlorite releases chlorine, which is a strong oxidizing agent that disrupts the cellular metabolism of microorganisms, leading to cell death.
• Dosage and Route:
  • Topical (Dakin’s Solution): Used in diluted forms (0.025% to 0.5%) for wound irrigation.
  • Surface Disinfection: Used in higher concentrations (e.g., 0.1% to 1%) for disinfecting surfaces.
• Indications:
  • Disinfection of surfaces and medical equipment.
  • Wound debridement and cleaning (Dakin’s Solution).
• Contraindications:
  • Hypersensitivity to chlorine or bleach.
  • Not for use on intact skin or large wounds without dilution.
  • Avoid contact with metals as it can cause corrosion.
• Drug Interactions:
  • Reacts with acids to produce toxic chlorine gas.
  • Reduced efficacy when mixed with other antiseptics or disinfectants.
• Side Effects:
  • Skin irritation, especially with prolonged contact or higher concentrations.
  • Respiratory irritation from fumes, particularly in enclosed spaces.
• Adverse Effects:
  • Corrosive to skin and mucous membranes at high concentrations, leading to chemical burns.
  • Inhalation of fumes can cause respiratory distress.
• Toxicity:
  • Ingestion or inhalation of concentrated bleach solutions can lead to severe toxicity, including burns, vomiting, and pulmonary edema.

Antiseptics and disinfectants are essential tools in infection control, each with specific uses, benefits, and risks. Understanding their composition, action, dosage, indications, and potential adverse effects is crucial for safe and effective use in healthcare and other settings. Proper selection and application of these agents help reduce the risk of infection while minimizing harm to patients and users.

Nursing Role and Responsibilities Related to Commonly Used Antiseptics and Disinfectants

Nurses play a critical role in the proper use of antiseptics and disinfectants in healthcare settings. Their responsibilities encompass ensuring the correct application of these agents, educating patients and healthcare staff, and maintaining a safe and hygienic environment to prevent infections.

1. Proper Selection and Application

• Assessment of Patient Needs:
  • Assess the patient’s condition to determine the appropriate antiseptic or disinfectant to use. This includes considering factors like skin integrity, presence of wounds, and the type of procedure being performed.
• Correct Usage:
  • Ensure that the appropriate antiseptic or disinfectant is selected based on the type of microorganism to be targeted, the area of application (e.g., skin, mucous membrane, surface), and the patient’s overall health condition.
  • Follow manufacturer instructions for dilution, application, and contact time to ensure efficacy and safety.
• Pre-Procedure Preparation:
  • Prepare the patient’s skin or mucous membranes with antiseptics before surgical procedures, catheter insertions, or other invasive procedures, following aseptic techniques.
  • Use disinfectants to prepare the environment, including sterilizing surgical instruments and disinfecting surfaces in the patient care area.

2. Education and Communication

• Patient Education:
  • Educate patients on the importance of antiseptics and how to use them properly for wound care or hand hygiene at home. Provide instructions on the correct application methods and potential side effects.
  • Inform patients about the risks of using over-the-counter antiseptics or disinfectants incorrectly, such as using them on open wounds or ingesting them.
• Staff Education:
  • Provide ongoing education to healthcare staff about the correct use of antiseptics and disinfectants, including updates on best practices, new products, and safety protocols.
  • Encourage adherence to infection control protocols, including proper hand hygiene and surface disinfection techniques.

3. Infection Control

• Aseptic Technique:
  • Maintain strict aseptic techniques when applying antiseptics to wounds, during catheter insertions, or before surgical procedures to prevent infections.
  • Ensure that all equipment used in patient care is properly disinfected before and after use.
• Environmental Hygiene:
  • Monitor and enforce the regular disinfection of surfaces and equipment in patient care areas, particularly in high-risk areas such as operating rooms, intensive care units, and isolation wards.
  • Ensure that high-touch surfaces (e.g., bed rails, doorknobs, IV stands) are frequently disinfected with appropriate agents.

4. Monitoring and Evaluation

• Observing Patient Response:
  • Monitor the patient for any signs of adverse reactions to antiseptics, such as skin irritation, allergic reactions, or systemic effects. Document and report any adverse reactions immediately.
  • Evaluate the effectiveness of antiseptic treatments on wounds or surgical sites, noting any signs of infection or delayed healing.
• Quality Control:
  • Participate in infection control audits to ensure compliance with disinfection protocols. Report any breaches or concerns to the infection control team.
  • Regularly check the expiration dates and integrity of antiseptic and disinfectant products, ensuring that expired or compromised products are not used.

5. Safety and Compliance

• Safe Handling and Storage:
  • Ensure that antiseptics and disinfectants are stored correctly, away from direct sunlight and at recommended temperatures, to maintain their efficacy.
  • Follow safety protocols for handling these agents, including the use of personal protective equipment (PPE) when necessary, to prevent accidental exposure.
• Waste Disposal:
  • Dispose of used or contaminated antiseptic and disinfectant materials (e.g., soaked gauze, used containers) according to hospital protocols and local regulations to prevent environmental contamination and exposure to hazardous substances.
• Documentation:
  • Accurately document the use of antiseptics and disinfectants in the patient’s medical record, including the type of agent used, the area of application, and any observed effects.
  • Report any incidents involving antiseptics or disinfectants, such as accidental ingestion or misuse, following the appropriate incident reporting procedures.

6. Involvement in Protocol Development

• Policy and Protocol Development:
  • Contribute to the development and review of hospital policies and protocols related to the use of antiseptics and disinfectants. Ensure that these policies reflect current evidence-based practices.
  • Participate in multidisciplinary infection control committees to discuss and address issues related to the use of antiseptics and disinfectants.
• Adherence to Guidelines:
  • Ensure that the use of antiseptics and disinfectants is in accordance with established guidelines from authoritative bodies such as the World Health Organization (WHO), Centers for Disease Control and Prevention (CDC), and hospital-specific protocols.

Nurses play an essential role in the safe and effective use of antiseptics and disinfectants, from selecting and applying the correct agents to educating patients and staff about their use. By adhering to best practices in infection control, monitoring patient responses, and ensuring compliance with safety protocols, nurses help to prevent healthcare-associated infections and ensure a safe environment for patients and healthcare workers alike.

Pharmacology of Commonly Used Antiseptics and Disinfectants

Antiseptics and disinfectants are chemical agents used to prevent infections by killing or inhibiting the growth of microorganisms. While antiseptics are applied to living tissues, disinfectants are used on inanimate objects. Below is a comprehensive discussion of commonly used antiseptics and disinfectants, their mechanisms, pharmacological actions, uses, and precautions.

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1. Classification of Antiseptics and Disinfectants

A. Based on Chemical Nature

1. Alcohols – Ethanol, Isopropyl alcohol
2. Halogens – Iodine, Povidone-iodine, Chlorine compounds
3. Phenolic Compounds – Phenol, Cresol, Chlorhexidine
4. Biguanides – Chlorhexidine gluconate
5. Quaternary Ammonium Compounds – Benzalkonium chloride, Cetylpyridinium chloride
6. Oxidizing Agents – Hydrogen peroxide, Potassium permanganate
7. Aldehydes – Formaldehyde, Glutaraldehyde
8. Heavy Metals – Silver sulfadiazine, Mercuric chloride
9. Dyes – Methylene blue, Crystal violet
10. Surfactants – Soaps, Detergents

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2. Pharmacology of Common Antiseptics and Disinfectants

1. Alcohols (Ethanol, Isopropyl Alcohol)

• Mechanism of Action: Causes protein denaturation, lipid dissolution, and disruption of cell membranes.
• Pharmacological Effects:
  • Rapid bactericidal action against vegetative bacteria.
  • Ineffective against bacterial spores.
  • Requires water for optimal activity (70% alcohol more effective than 100%).
• Uses:
  • Hand sanitization.
  • Skin antisepsis before injections.
  • Disinfection of small medical instruments.
• Precautions:
  • Highly flammable.
  • Irritant to wounds and mucous membranes.

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2. Halogens (Iodine, Povidone-Iodine, Chlorine Compounds)

• Mechanism of Action: Oxidizes microbial proteins and disrupts metabolic processes.
• Pharmacological Effects:
  • Broad-spectrum antimicrobial activity.
  • Effective against bacteria, viruses, fungi, and spores.
• Uses:
  • Iodine: Pre-surgical skin antisepsis, wound cleansing.
  • Povidone-Iodine: Used in surgical scrubs, hand washes, and wound dressings.
  • Chlorine Compounds (Sodium Hypochlorite, Chlorine Gas): Used for water disinfection and surface cleaning.
• Precautions:
  • Can cause skin irritation and hypersensitivity.
  • Chlorine can produce toxic fumes.

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3. Phenolic Compounds (Phenol, Cresol, Chlorhexidine)

• Mechanism of Action: Disrupts cell membranes and precipitates proteins.
• Pharmacological Effects:
  • Broad-spectrum antimicrobial activity.
  • Active against bacteria, fungi, and some viruses.
  • Limited action against spores.
• Uses:
  • Phenol: Historically used but now limited due to toxicity.
  • Cresol: Used in disinfecting floors, walls, and equipment.
  • Chlorhexidine: Used as a surgical hand scrub, mouthwash (oral antiseptic), and wound antiseptic.
• Precautions:
  • Phenol is toxic and corrosive.
  • Chlorhexidine may cause hypersensitivity reactions.

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4. Biguanides (Chlorhexidine Gluconate)

• Mechanism of Action: Alters bacterial cell membrane permeability, leading to leakage of cell contents.
• Pharmacological Effects:
  • Effective against Gram-positive and Gram-negative bacteria.
  • Less effective against spores and some viruses.
• Uses:
  • Preoperative skin disinfection.
  • Handwashing solutions for healthcare workers.
  • Oral antiseptic in mouthwashes (e.g., for gingivitis).
• Precautions:
  • Rare allergic reactions.
  • Can cause eye and ear toxicity if used inappropriately.

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5. Quaternary Ammonium Compounds (Benzalkonium Chloride, Cetylpyridinium Chloride)

• Mechanism of Action: Disrupts cell membranes, leading to leakage of cell contents.
• Pharmacological Effects:
  • Effective against bacteria and some viruses.
  • Not sporicidal.
• Uses:
  • Disinfection of surfaces and medical equipment.
  • Found in antiseptic mouthwashes and hand sanitizers.
• Precautions:
  • Inactivated by organic matter.
  • Not effective against bacterial spores and Mycobacterium tuberculosis.

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6. Oxidizing Agents (Hydrogen Peroxide, Potassium Permanganate)

• Mechanism of Action: Releases oxygen free radicals that damage microbial cells.
• Pharmacological Effects:
  • Broad-spectrum antimicrobial action.
  • Effective against bacteria, viruses, fungi, and spores.
• Uses:
  • Hydrogen peroxide: Used in wound cleaning and as a disinfectant.
  • Potassium permanganate: Used in dermatological conditions like fungal infections.
• Precautions:
  • Can cause skin irritation and delayed wound healing.
  • Hydrogen peroxide may cause tissue damage in deep wounds.

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7. Aldehydes (Formaldehyde, Glutaraldehyde)

• Mechanism of Action: Crosslinks proteins and nucleic acids, leading to microbial death.
• Pharmacological Effects:
  • Broad-spectrum antimicrobial activity.
  • Effective against bacteria, viruses, fungi, and spores.
• Uses:
  • Disinfection of medical instruments (e.g., endoscopes, surgical tools).
  • Formaldehyde is used for preserving biological specimens.
• Precautions:
  • Toxic fumes can cause respiratory irritation.
  • Requires proper ventilation during use.

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8. Heavy Metals (Silver Sulfadiazine, Mercuric Chloride)

• Mechanism of Action: Inactivates enzymes by binding to thiol groups.
• Pharmacological Effects:
  • Broad antimicrobial activity.
  • Effective against bacteria and some fungi.
• Uses:
  • Silver sulfadiazine: Used in burn wound dressings.
  • Mercuric chloride: Historically used, now rarely due to toxicity.
• Precautions:
  • Silver compounds may cause skin discoloration.
  • Mercury compounds are highly toxic and no longer recommended.

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9. Dyes (Methylene Blue, Crystal Violet)

• Mechanism of Action: Interferes with microbial DNA synthesis.
• Pharmacological Effects:
  • Antibacterial and antifungal properties.
• Uses:
  • Methylene blue: Used in urinary tract infections.
  • Crystal violet: Used in the treatment of fungal infections.
• Precautions:
  • May cause staining of skin and clothes.
  • Can cause irritation to mucous membranes.

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10. Surfactants (Soaps and Detergents)

• Mechanism of Action: Reduce surface tension, disrupting microbial cell membranes.
• Pharmacological Effects:
  • Mild antiseptic activity.
  • Primarily used for mechanical removal of microbes.
• Uses:
  • Handwashing.
  • Cleaning medical instruments.
• Precautions:
  • Requires proper rinsing to remove all residues.

Pharmacology of Commonly Used Antiseptics and Disinfectants

Below is a detailed analysis of various antiseptics and disinfectants, covering composition, action, dosage, route, indications, contraindications, drug interactions, side effects, adverse effects, and toxicity.

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1. Alcohols (Ethanol, Isopropyl Alcohol)

Composition

• Ethanol (60-90%)
• Isopropyl alcohol (70-90%)

Action

• Denatures proteins, dissolves lipids, and disrupts cell membranes.
• Rapid bactericidal activity, also effective against fungi and some viruses.
• Ineffective against bacterial spores.

Dosage and Route

• Hand sanitization: 60-70% ethanol-based solutions applied directly to skin.
• Skin antisepsis before injections: Apply 70% ethanol or isopropyl alcohol using a sterile swab.
• Disinfection of medical instruments: 70-90% ethanol for 5-10 minutes.

Indications

• Hand antisepsis.
• Preoperative skin disinfection.
• Disinfection of medical instruments and surfaces.

Contraindications

• Open wounds (causes irritation).
• Mucosal application (causes burning).
• Hypersensitivity to alcohol.

Drug Interactions

• Chlorhexidine: May precipitate in alcohol solutions.
• Iodine-based antiseptics: Alcohol reduces their efficacy.

Side Effects

• Dryness and irritation of skin.
• Burning sensation.
• Temporary redness.

Adverse Effects

• Systemic absorption leading to neurotoxicity and respiratory depression in excessive use.
• Flammability hazard leading to burns if used near flames.

Toxicity

• Inhalation toxicity: Causes dizziness, headache, nausea.
• Ingestion: CNS depression, hypoglycemia, metabolic acidosis.
• Treatment: Supportive care, fluid therapy.

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2. Halogens (Iodine, Povidone-Iodine, Chlorine Compounds)

Composition

• Iodine: Elemental iodine, alcohol base.
• Povidone-Iodine: 10% solution (contains 1% available iodine).
• Chlorine Compounds: Sodium hypochlorite (0.5-5%), Chloramine.

Action

• Oxidizes microbial proteins, disrupts metabolic pathways.
• Effective against bacteria, viruses, fungi, and spores.

Dosage and Route

• Iodine tincture: Applied as a 2-5% solution to the skin.
• Povidone-iodine: Used as a 10% solution for wound dressing and pre-surgical scrubbing.
• Sodium hypochlorite: 0.5% for wound irrigation, 5% for surface disinfection.

Indications

• Skin antisepsis (preoperative).
• Wound care.
• Water disinfection (chlorine compounds).

Contraindications

• Allergy to iodine.
• Thyroid disorders (iodine absorption may affect thyroid function).
• Not recommended for neonates due to risk of hypothyroidism.

Drug Interactions

• Silver sulfadiazine: Reacts with iodine and inactivates both.
• Hydrogen peroxide: Reduced efficacy when used together.

Side Effects

• Skin irritation and discoloration.
• Burning sensation.

Adverse Effects

• Hypersensitivity reactions.
• Systemic iodine absorption: May lead to hypothyroidism or hyperthyroidism.

Toxicity

• Excess iodine ingestion: Thyroid dysfunction, metabolic acidosis.
• Treatment: IV hydration, activated charcoal for oral overdose.

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3. Phenolic Compounds (Phenol, Cresol, Chlorhexidine)

Composition

• Phenol: 1-5% solutions.
• Cresol: Lysol (disinfectant) 5-10%.
• Chlorhexidine: 2-4% solutions for antisepsis.

Action

• Disrupts cell membranes, denatures proteins.
• Broad-spectrum activity.

Dosage and Route

• Phenol-based disinfectants: Used on surfaces, not for human use.
• Chlorhexidine: 0.2% mouthwash, 2% for hand disinfection, 4% for preoperative skin cleaning.

Indications

• Skin disinfection (Chlorhexidine).
• Oral antiseptic (Chlorhexidine mouthwash).

Contraindications

• Hypersensitivity.
• Not for use in open wounds (causes toxicity).

Drug Interactions

• Incompatible with soaps and anionic detergents.

Side Effects

• Skin irritation.
• Taste alteration (with mouthwash).

Adverse Effects

• Chlorhexidine: Anaphylactic reactions, eye and ear toxicity.

Toxicity

• Phenol poisoning: Causes severe burns, CNS toxicity.
• Management: Supportive care, activated charcoal if ingested.

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4. Quaternary Ammonium Compounds (Benzalkonium Chloride, Cetylpyridinium Chloride)

Composition

• Benzalkonium chloride (0.1-0.2%).
• Cetylpyridinium chloride (0.05-0.1%).

Action

• Disrupts cell membranes, leading to microbial death.

Dosage and Route

• Used as surface disinfectants, antiseptic solutions.
• Found in mouthwashes, hand sanitizers.

Indications

• Hand hygiene.
• Surface disinfection.

Contraindications

• Not for invasive medical instruments (can be inactivated by organic matter).

Drug Interactions

• Inactivated by soap, anionic detergents.

Side Effects

• Skin irritation, allergic contact dermatitis.

Adverse Effects

• Respiratory distress if inhaled in high concentration.

Toxicity

• Oral ingestion: Causes gastrointestinal irritation.
• Treatment: Supportive care, activated charcoal.

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5. Oxidizing Agents (Hydrogen Peroxide, Potassium Permanganate)

Composition

• Hydrogen Peroxide (3-6%).
• Potassium Permanganate (0.01-0.1%).

Action

• Releases oxygen radicals, damaging microbial cells.

Dosage and Route

• Hydrogen peroxide: Used as 3% solution for wound cleaning.
• Potassium permanganate: Used in 0.01% solution for dermatitis.

Indications

• Wound antiseptic.
• Water disinfection (high concentration).

Contraindications

• Deep wounds (oxygen release can cause tissue necrosis).

Drug Interactions

• Inactivated by organic material.

Side Effects

• Skin dryness.

Adverse Effects

• Delayed wound healing if overused.

Toxicity

• Hydrogen peroxide ingestion: Causes gas embolism, gastric irritation.
• Treatment: Oxygen therapy, supportive care.