PH9.5 | PH9.5 | Antiseptics and Disinfectants — SDL Guide — Summary & Reflection

KEY TAKEAWAYS

Antiseptics are safe for living tissue; disinfectants are for inanimate surfaces. The Spaulding classification guides decontamination level: Critical items (sterile tissue contact) → sterilisation (autoclave preferred; glutaraldehyde 10h for heat-sensitive); Semi-critical items (mucous membrane contact, endoscopes) → high-level disinfection (glutaraldehyde 2% for 20–30 min); Non-critical items (intact skin contact) → low-level disinfection (QACs, alcohols). Chemical classes and uses: Oxidising agents (H₂O₂ 3% wound cleaning; NaOCl bleach surface disinfection); Halogens (povidone-iodine — broad spectrum wound antisepsis; water purification tablets); Phenols (chloroxylenol/Dettol — DILUTE before wound use); Alcohols (70% ethanol/isopropanol — NOT sporicidal; soap-and-water for C. diff); Biguanides (chlorhexidine — residual activity, preoperative skin prep RCT-proven, ototoxic, not for ear); Aldehydes (glutaraldehyde 2% — endoscope HLD, tissue toxic, requires PPE and rinsing); QACs (benzalkonium chloride/cetrimide — low-level, inactivated by soap and organic matter, Pseudomonas resistant). Ethanol 70% is optimal — NOT 100%. Chlorhexidine-alcohol superior to povidone-iodine-alcohol for surgical skin prep.

REFLECT

Think about the last time you saw a wound dressed in a clinical setting. Was the choice of antiseptic appropriate for the wound stage (acute contaminated vs healing chronic wound)? Was it diluted correctly? Was the contact time respected? In your community, which antiseptic and disinfectant products are most commonly available and used? Are there common misuse patterns that a physician should educate patients about (e.g. undiluted Dettol on wounds, using alcohol for environmental disinfection of C. diff-contaminated surfaces)? How does your understanding of antiseptic pharmacology change the advice you would give to patients and caregivers?