Chlorhexidine

BRAND NAMES

• Hibiclens

• Hibitane

• Corsodyl

• Peridex

• Savlon (combination product)

MECHANISM OF ACTION

Chlorhexidine acts by binding to negatively charged components of microbial cell walls, disrupting the integrity of the cell membrane. This interaction increases membrane permeability, leading to leakage of essential intracellular substances such as proteins and nucleic acids. At lower concentrations, it exhibits a bacteriostatic effect by inhibiting microbial growth, while at higher concentrations, it becomes bactericidal, causing irreversible damage and cell death. This mechanism makes it effective against a wide range of microorganisms, including bacteria, fungi, and some viruses.

PHARMACOKINETICS

Absorption

Chlorhexidine is poorly absorbed through intact skin and mucous membranes. When applied topically or used as a mouthwash, only minimal amounts enter systemic circulation, making its action primarily local.

Distribution

The volume of distribution (Vd) of chlorhexidine is very low, approximately 0.2–0.3 L/kg, reflecting its poor systemic absorption and strong binding to tissues.

Metabolism

Chlorhexidine undergoes minimal metabolism in the body. Most of the small fraction that is absorbed systemically remains largely unchanged and is eventually excreted, primarily via the feces, with very little renal elimination

Excretion

Chlorhexidine is primarily excreted unchanged in the feces. Only a very small amount is eliminated via the urine, reflecting its minimal systemic absorption.

PHARMACODYNAMICS

Chlorhexidine disrupts microbial membranes, causing cell death. Low concentrations inhibit growth, high concentrations kill microbes, with lasting effects on skin and mucous membranes.

ADMINISTRATION

Chlorhexidine is a widely used antiseptic and disinfectant used to reduce or kill bacteria on the skin, in the mouth, and on medical instruments. Its administration depends on the form (solution, mouthwash, gel, or surgical prep).

DOSAGE AND STRENGTH

• Skin antisepsis: Apply 2–4% solution directly to the area before surgery or invasive procedures.

• Oral use (mouthwash): 0.12–0.2% solution, rinse for 30 seconds twice daily.

• Wound care: Use 0.05–4% solution as a topical antiseptic.

• Hand hygiene: 2–4% solution for hand scrubs in healthcare settings.

DRUG INTERACTIONS

• Cetylpyridinium chloride and other cationic agents: May reduce chlorhexidine’s antimicrobial activity.

• Anionic compounds (e.g., toothpaste with sodium lauryl sulfate): Can inactivate chlorhexidine if used immediately before or after oral rinses.

• Alcohol-based mouthwashes: May enhance irritation when combined with chlorhexidine.

• Topical antiseptics: Combining with strong oxidizing agents (like iodine or hydrogen peroxide) may reduce efficacy.

FOOD INTERACTIONS

• There are no significant systemic food interactions because chlorhexidine is minimally absorbed.

• For oral use, avoid eating or drinking for 30 minutes after rinsing to maintain antimicrobial effectiveness and prevent reduced efficacy.

CONTRAINDICATIONS

• Known hypersensitivity to chlorhexidine or any component of the formulation

• Severe oral mucosal ulceration (for mouthwash use)

• Open ear woundsor tympanic membrane perforation (for ear preparations)

• Use in neonates on large broken skin areas, unless advised by a physician

SIDE EFFECTS

• Mild oral irritation

• Altered taste

• Staining of teeth or tongue

• Skin dryness

• Itching or redness at application site

• Rare: severe hypersensitivity or anaphylaxis

• Long-term oral use: tartar buildup or mucosal ulceration

OVER DOSE

• Nausea, vomiting, diarrhea, abdominal pain

• Mouth or throat irritation

• Rare: hypotension or respiratory distress

TOXICITY

Chlorhexidine has minimal systemic toxicity due to poor absorption. Prolonged or excessive use can cause tooth or tongue staining, mucosal irritation, and, in rare cases, allergic or hypersensitivity reactions. No significant damage to internal organs has been reported.