Chlorhexidine is a widely used antiseptic agent with a pronounced bactericidal type of action. Chemically, the drug is a dichlorinated biguanide derivative. It actively disrupts the cell membranes of pathogenic microorganisms and has found extensive application in surgical, dental, and venereological practice for disinfection and the management of inflammatory conditions.
Chemical groupDichlorinated biguanide derivative
Type of actionBactericidal (causes microbial cell death)
SusceptibleGram(+) and Gram(-) bacteria, protozoa, herpes simplex virus
ResistantBacterial spores, fungi, *Mycobacterium tuberculosis*, other viruses
Mechanism of Action
Chlorhexidine fundamentally differs in its mechanism from inorganic chlorine compounds. Its bactericidal effect is executed in three consecutive stages, leading to the irreversible destruction of the microbial cell:
Initially, the antiseptic molecule closely attaches to the cell membrane of the bacterium.
This interaction disrupts the barrier function of the membrane, triggering a rapid leakage of small vital molecules from the intracellular space outward.
At the final stage, precipitation (coagulation) of cytoplasmic proteins occurs. As a result of this extensive damage, the microorganism inevitably dies.
Antimicrobial Spectrum
The drug exhibits a broad spectrum of activity, though it has clear limitations regarding microbial susceptibility.
High susceptibility: The antiseptic effectively eliminates both Gram-positive and Gram-negative bacteria. This list includes streptococci, gonococci, bacteroids, and Gardnerella. Specific pathogens are also highly susceptible: Treponema pallidum, intracellular parasites (chlamydia and ureaplasma), protozoa (particularly trichomonads), and the herpes virus.
Complete resistance: The drug is ineffective against bacterial spores and fungi. Notably, Mycobacterium tuberculosis is also resistant to its effects. Furthermore, the vast majority of viruses (with the exception of the herpes virus) are completely insusceptible to this biguanide derivative.
Clinical Application in Medicine
Due to its potent bactericidal activity, the drug has become an indispensable tool across several medical disciplines:
In surgical practice: Solutions are used for thorough scrubbing of the operating surgeon's hands and preparation of the operative field. The agent is also suitable for cold sterilization of surgical instruments. In purulent surgery, the drug is used to manage septic processes: active irrigation of infected surgical wounds, burn surfaces, and urinary bladder flushing.
In dentistry: Prescribed as therapeutic mouthwashes for various inflammatory diseases of the gums and oral mucosa, such as gingivitis, stomatitis, and periodontitis.
In venereology: Serves as a reliable agent for individual emergency prophylaxis of sexually transmitted infections (STIs). Timely application reduces the risk of contracting syphilis, gonorrhea, trichomoniasis, chlamydia, and ureaplasmosis.
Side Effects
Despite high clinical efficacy, topical application of the drug is not always without adverse effects. Regular scrubbing of medical personnel's hands can lead to unwanted skin reactions. The most common side effects include pronounced skin dryness, persistent itching, and the development of contact dermatitis.
Mnemonic
To remember the spectrum of activity in venereology, use the mnemonic "SGT-CU": Syphilis, Gonorrhea, Trichomoniasis, Chlamydia, Ureaplasmosis — these are the main infections for which chlorhexidine is effective for individual prophylaxis.
Frequently asked questions
At what concentrations are aqueous and alcoholic solutions of chlorhexidine used depending on the indications?
The concentration and type of solution used depend on clinical indications and the goals of antiseptic treatment.
Chlorhexidine solution — at a concentration of 0.05% is used for gargling in meningococcal infection and jet irrigation of the tooth socket in the management of alveolitis.
Aqueous-alcoholic solution (Chlorhexidini bigluconas) — at a concentration of 0.5% is prepared from a 20% solution by dilution with 70% ethanol at a 1:40 ratio. Used for operative field preparation and instrument disinfection.
Alcoholic chlorhexidine solution — without specifying an exact concentration, it is the drug of choice for prepping the surgical field during pacemaker implantation.
Chlorhexidine solution at a concentration of 0.06% is mentioned as a disinfecting solution in which anesthetic carpules must strictly not be immersed.
To which chemical group does chlorhexidine belong?
It is a dichlorinated biguanide derivative. On exams, it is important not to confuse it with iodophores, phenol derivatives, or quaternary ammonium compounds.
How exactly does the drug kill the bacterial cell?
The mechanism includes three stages: attachment to the membrane, leakage of small molecules from the cell, and final precipitation (coagulation) of cytoplasmic proteins.
Can this agent be used to eliminate spores and viruses?
Bacterial spores show absolute resistance to the drug. Regarding viruses, only the herpes virus exhibits susceptibility; all other viruses are resistant.
Is chlorhexidine effective against tuberculosis?
No, Mycobacterium tuberculosis is resistant to this antiseptic, despite other species of streptococci and bacteria being susceptible.
Go deeper
Comparative characteristics of biguanides and inorganic chlorine compounds.
Mechanisms of natural resistance of Mycobacterium tuberculosis and spores to antiseptics.
Protocols for cold sterilization of surgical instruments using chemical solutions.
Pharmacological prophylaxis of STIs: timing and rules for antiseptic application.
Management and prevention of occupational contact dermatitis in surgical personnel.