Chlorhexidine

Chlorhexidine is used in disinfectants (disinfection of the skin and hands), cosmetics (additive to creams, toothpaste, deodorants, and antiperspirants), and pharmaceutical products (preservative in eye drops, active substance in wound dressings and antiseptic mouthwashes). In endodontics, chlorhexidine has been used for root canal irrigation and as an intracanal dressing. Antiseptic Chlorhexidine is active against Gram-positive and Gram-negative organisms, facultative anaerobes, aerobes, and yeasts. There is strong evidence that chlorhexidine is more effective than povidone-iodine for clean surgery.. Recent evidence has demonstrated a dose-response relationship, whereby 2% chlorhexidine is more effective than 0.5% for the prevention of SSI although the dose-related risk of adverse events remains unknown. Meta-data spanning several decades shows that the efficacy of chlorhexidine (against organisms that cause surgical site infection) has not changed, dispelling concerns over emerging resistance. Dental use Use of a chlorhexidine-based mouthwash in combination with normal tooth care can help reduce the build-up of plaque and reduce mild gingivitis. There is not enough evidence to determine the effect in moderate to severe gingivitis. Chlorhexidine gel can be applied to a wound following a tooth extraction to decrease the incidence of dry socket (inflammation of the alveolar bone). Chlorhexidine is a cation which interacts with anionic components of toothpaste, such as sodium lauryl sulfate and sodium monofluorophosphate, and forms salts of low solubility and reduced antibacterial activity. Hence, to enhance the antiplaque effect of chlorhexidine, "it seems best that the interval between toothbrushing and rinsing with CHX [chlorhexidine] be more than 30 minutes, cautiously close to two hours after brushing". Topical Chlorhexidine gluconate is used as a skin cleanser for surgical scrubs, as a cleanser for skin wounds, for preoperative skin preparation, and for germicidal hand rinses. Chlorhexidine is a very effective antiseptic and its use is growing in the world for treating the umbilical cord. A 2015 Cochrane review has yielded high-quality evidence that within the community setting, chlorhexidine skin or cord care can reduce the incidence of omphalitis (inflammation of the umbilical cord) by 50% and neonatal mortality by 12%. == Side effects ==

Side effects may include skin irritation, tooth discoloration, and allergic reactions, Chlorhexidine does not meet European specifications for a hand disinfectant. Under the test conditions of the European Standard EN 1499, no significant difference in the efficacy was found between a 4% solution of chlorhexidine digluconate and soap. Whether prolonged exposure over many years may have carcinogenic potential is still not clear. The US Food and Drug Administration recommendation is to limit the use of a chlorhexidine gluconate mouthwash to a maximum of six months. When ingested, chlorhexidine is poorly absorbed in the gastrointestinal tract and can cause stomach irritation or nausea. If aspirated into the lungs at high enough concentration, as reported in one case, it can be fatal due to the high risk of acute respiratory distress syndrome. ==Mechanism of action==

At physiologic pH, chlorhexidine salts dissociate and release the positively charged chlorhexidine cation. The bactericidal effect is a result of the binding of this cationic molecule to negatively charged bacterial cell walls. At low concentrations of chlorhexidine, this results in a bacteriostatic effect; at high concentrations, membrane disruption results in cell death. ==Chemistry==

It is a cationic (bisbiguanide). == Deactivation ==

Chlorhexidine is deactivated by forming insoluble salts with anionic compounds, including the anionic surfactants commonly used as detergents in toothpastes and mouthwashes, anionic thickeners such as carbomer, and anionic emulsifiers such as acrylates/C10-30 alkyl acrylate , among many others. For this reason, chlorhexidine mouth rinses should be used at least 30 minutes after other dental products. == Synthesis ==

The structure is based on two molecules of proguanil, linked with a hexamethylenediamine spacer. ). The compounds designated (...)2 are substituted hexanes. == Society and culture ==

Brands Chlorhexidine topical is sold as Betasept, Biopatch, Calgon Vesta, ChloraPrep One-Step, Dyna-Hex, Hibiclens, Hibistat Towelette, Scrub Care Exidine, and Spectrum-4, among others. Chlorhexidine gluconate mouthwash is sold as Dentohexin, Paroex, Peridex, PerioChip, Corsodyl, Chlorhexamed and Periogard, among others. ==Veterinary medicine==

In animals, chlorhexidine is used for topical disinfection of wounds, and to manage skin infections. Chlorhexidine-based disinfectant products are used in the dairy farming industry. Post-surgical respiratory problems have been associated with the use of chlorhexidine products in cats. == References ==