Chapter 2: Table of Contents
Chlorhexidine is a bisbiguanide that is useful for killing bacteria, viruses, and fungi. Chlorhexidine has a broad spectrum of activity but is more effective against gram-positive bacteria than gram-negative bacteria (i.e. Pseudomonas sp.) and fungi. It is effective against enveloped viruses but like other antiseptics has poor activity against spores. It is available in numerous forms such as detergents (soap used for initial patient skin scrub), tinctures (pre-surgical preparation – final step) and aqueous forms (pre-surgical preparation for open wounds, flushing prepuce). When used for scrubbing hands or patients, it is non-irritating to the skin and works within 30 seconds to kill organisms. Despite a rapid onset of action, contact times of 2 minutes are still recommended to reach maximum killing and better residual activity.
Chlorhexidine is irritating to the eye, ototoxic and neurotoxic if it contacts the brain or meninges. It kills microorganisms by increasing cell membrane permeability and precipitation of the cell contents. Residual activity that lasts at least 6 hours is present due to binding to keratin, and effectiveness increases with repeated uses. The presence of organic debris does not affect the activity of chlorhexidine.