Antiseptics & Disinfectants

Current · V5 (2025) → O2.v Historical · V4 (2023) → T2.iii 1 exam appearance

2008A Q14

Exam question

Define the terms antiseptic and disinfectant. Briefly describe the advantages and disadvantages of alcohol, chlorhexidine, glutaraldehyde and povidone iodine.

CICMWrecks answer

Master answer

Disinfectants
- Strong chemical compounds that kill of inhibit the growth of microbes
Antiseptic
- Disinfectants with sufficiently low toxicity to host cells, that can be used directly on skin, wounds or mucosa

Antiseptics & Disinfectants — Level 3
CATEGORY	ITEM	ALCOHOL	CHLORHEXIDINE	IODINE	GLUTARALDEHYDE
Basics	CICM Level of Understanding	Level 3	Level 3	Level 3	–
PD	Main Action	Likely act by denaturing proteins	Cationic biguanide -strongly adsorbs to bacterial membranes causing leakage of small particles and precipitation of cytoplasmic proteins	Oxidative damage.	Alkylation of micro-organism proteins or nucleic acids
PD	Mode of Action	Evaporative effects are useful when sinks with running water are not available	Resistant to inactivation by blood and organic material Low skin irritation	1. Sporicidal 2. Cheap 3. Broad spectrum Most effective for intact skin	Used for sterilization of equipment that cannot withstand high temperatures
PD	Route & Doses	1. Flammable- must be allowed to dry fully before diathermy or laser surgery 2. Corneal damage 3. Skin drying 4. Ineffective against C. Dif spores	1. Neurotoxic 2. Delayed effect 3. No direct spore activity	1. Hypersensitivity reactions 2. Delayed onset without residual activity 3. Stains clothes and dressings	1. Once activated have a shelf life of 14 days 2. Failure of activity may occur due to excessive dilution or exposure to organic material (frequently reused) 3. Irritating to eyes and respiratory mucosa 4. Slow activity
PD	Spectrum of Activity	Onset: Rapid Duration: Lack residual action because they evaporate completely	Onset: Delayed Duration: Sustained residual activity	Onset: Iodine is bacteriocidal in 1 minute and kills spores in 15 minutes. However in povidine compounding it has a delayed onset Duration: No sustained effect	Onset: 2.4% glutaraldehyde achieve disinfection in 45 minutes
PD	Resistance Mechanism	– Gram positives and negatives – Acid fast bacteria are susceptible – Lipophilic viruses may be susceptible – Many fungi	– Bacteria (G+ve>G-ve) – Moderate fungal and viral activity – Inhibits spore germination	– Bacteria (G+ve and –ve and acid fast) – Sporicidal – Viruses – Fungi	– Bacteria (G+ve and –ve and acid fast) – Spores – Viruses – Fungi
PD	Ineffective Against:	Spores and prions Hydrophilic viruses are less susceptible	Spores and prions Hydrophilic viruses are less susceptible	Prions Hydrophilic viruses	Prions
Spl	SPECIAL POINTS	Optimal bacteriocidal concentration is 60-90%	Can be combined with 70% alcohol Preferred antiseptic for central venous access Not absorbed orally		Used to sterilize fiber optic endoscopes and respiratory therapy equipment

Sakurai 2016

Answer by Sakurai

Past papers

Exam appearances

1 appearance

Exam	Exact exam wording	Candidate success
2008A Q14	Define the terms antiseptic and disinfectant. Briefly describe the advantages and disadvantages of alcohol, chlorhexidine, glutaraldehyde and povidone iodine.	—