T2iii: Outline the pharmacology of antiseptics and disinfectants

Definitions

Antiseptic  =    substance applied topically to prevent growth of micro-organisms

Not for use on inaminate objects bc does not have the same killing power of chemicals used for disinfection

Disinfectant = agent applied topically to inanimate object to destroy pathogens

Class

Alcohol

Antiseptic

Chlorhexidine

Antiseptic

Povidine Iodine

Antiseptic

Glutaraldehyde

Disinfectant

Presentation

Alcohol

70% Isopropyl Alcohol

Chlorhexidine

Aqueous or combined with alcohol

Povidine Iodine

Iodine combined with polymer (povidone) to enhance water solubility

Glutaraldehyde

Pugnent, colourless, oily liquid

MoA

Alcohol

Denatures proteins

Chlorhexidine

At physiological pH

Chlorehex salts dissociate

Release + charge

Cation binds -ve charge bac cell wall

Chlorhex denatures proteins & lipids of bac = lysis

Povidine Iodine

Povidone carries Iodine to pathogen

Iodine penetrates cell wall and membrane

Pore insertion = bactericidal

Glutaraldehyde

Associates w bacterial cell wall

Cross linking inhibits further bacterial cell fns

Antiviral

Alcohol

Poor viral

Chlorhexidine

Poor antiviral

Povidine Iodine

Good antiviral

Glutaraldehyde

Antibacterial

Alcohol

Broad spectrum

Chlorhexidine

G + > – > fungi

Povidine Iodine

Broad spectrum

G + > – > fungi > virus

Glutaraldehyde

Advantages

Alcohol

Broad spectrum Gram cover, fungi

Kills 90% skin bacteria in 2mins

Doesn’t need to dry for effect – evaporation limits its microbe activity

Chlorhexidine

Rapid onset, lasts 48hrs

Povidine Iodine

Can be used following 70% alcohol to keep recolonization down for 60mins

Area of application visible

Can be used w chlorhex allergy

Glutaraldehyde

Broad spectrum:

Bacteria, their spores, fungi, viruses, mycobacteria

Disadvantages

Alcohol

Flammable

Irritant to skin

Potential for allergy

Chlorhexidine

Requires 30sec scrub

Neurotoxic

Flammable

Cannot be used directly on mucosa

Povidine Iodine

Cannot be used if hyperthyroid

Glutaraldehyde

Irritant

Contact dermatitis

Pungent odour