Chlorhexidine

Chlorhexidine is a chemical antiseptic and antimicrobial agent widely used in medical, dental, and consumer products. It is a cationic bisbiguanide available as digluconate or diacetate salts. In solution, chlorhexidine remains active across a range of pH levels and is relatively low in toxicity for topical use. Common preparations include mouthrinses around 0.12%, topical skin solutions from about 0.5% to 2%, and surgical scrubs near 2%.

Mechanism of action involves binding to negatively charged microbial cell walls, disrupting membranes, and causing leakage of cellular contents. At lower concentrations, it is generally bacteriostatic; at higher concentrations, bactericidal. Chlorhexidine also has activity against some fungi and enveloped viruses, with limited activity against bacterial spores and non-enveloped viruses.

Uses include preoperative skin antisepsis and hand hygiene, including alcohol-based formulations for healthcare workers, and cleaning of wounds and catheter sites. In dentistry, chlorhexidine mouthwash reduces dental plaque and gingivitis and is used as an adjunct in periodontal therapy and occasionally as an endodontic irrigant.

Safety and limitations: Common adverse effects in oral use include staining of teeth and tongue, altered taste, and mucosal irritation. Allergic reactions are possible but uncommon. Efficacy can be reduced by organic matter or in the presence of anionic detergents; in mouth care, toothpaste containing sodium lauryl sulfate can interfere, so rinsing is typically separated from brushing by about 30 minutes. Proper use and concentration depend on the clinical context.