Chlorhexidine

Overview
Chlorhexidine is a chemical antiseptic. It kills (is bactericidal to) both gram-positive and gram-negative microbes, although it is less effective with some gram-negative microbes. It is also bacteriostatic.

The mechanism of action is believed to be membrane disruption, and not ATPase inactivation as previously thought.

Products containing chlorhexidine in high concentrations must be kept away from eyes (corneal ulcers) and the inner ear (deafness), although it is used in minute concentrations in some contact lens solutions.

Availability
It is sometimes marketed under the brand names Peridex, Periochip, Periogard Oral Rinse. In the UK it is sometimes marketed under the brand names Corsodyl or Chlorohex, in Germany as Chlorhexamed, in Australia as Savacol, in Venezuela as Perioxidina and in some Central American countries as Clorexil.

In some countries it is available by prescription only.

Dental applications
It is often used as an active ingredient in mouthwash designed to kill dental plaque and other oral bacteria. Chlorhexidine can thus be used to improve bad breath.

Chlorhexidine based products are usually utilized to combat or prevent gum diseases such as gingivitis. According to Colgate, chlorhexidine gluconate has not been proven to reduce subgingivial calculus and in some studies actually increased deposits.

Deactivation
Chlorhexidine is deactivated by anionic compounds, including the anionic surfactants commonly used as detergents in toothpastes and mouthwashes. For this reason, chlorhexidine mouth rinses should be used at least 30 minutes after other dental products. For best effectiveness, food, drink, smoking, and mouth rinses should be avoided for at least one hour after use.

Non-dental applications
Chlorhexidine is also used in non-dental applications, most notably under the brand names Oronine, Avagard, Hibiclens, Hibiscrub, ChloraPrep, BIOPATCH, and Exidine. It is also a component of the famous household antiseptic Savlon. It is used for general skin cleansing, a surgical scrub and a pre-operative skin preparation. Due to other chemicals listed as inactive ingredients, the cleanser solution is not suitable for use as mouthwash. It is often used as a rubbing agent prior to the use of hypodermic or intravenous needles in place of iodine. Chlorhexidine is contraindicated for use near the meninges, in the genital area, and near the eyes and ears. At the 2% concentration, it can cause serious and permanent injury on contact with the eye or if instilled through a perforated eardrum. As a scrub it is not recommended on persons under two months of age. It can be used also as spermatocidal agent.