Powerful disinfectant
Chlorhexidine is a synthetic antibacterial agent used to disinfect skin and oral mucosa. Very effective against gram-positive bacteria, chlorhexidine proves to be quite active also towards gram-negative bacteria; furthermore, it appears that the substance is moderately active against encapsulated fungi and viruses.
At high concentrations, chlorhexidine is extremely harmful to the body; however, when diluted appropriately, it is widely used to prepare antiseptic mouthwashes (disinfectants), solutions for contact lenses and other products disinfected for hands and mucous membranes.
Chemical analysis
From the chemical point of view, chlorhexidine is a cationic biguanide that is poorly soluble in water. To make it water-soluble, the substance must be combined (or rather, salified) with gluconic acid: not by chance, in the preparation of the mouthwash the compound is in the form of chlorhexidine digluconate.
Chlorhexidine acts in two ways:
- Powerful bactericide (main effect). Chlorhexidine goes to alter the protein structure of the bacterial cell membrane: by exaggeratingly increasing its permeability, the substance promotes the precipitation of cytoplasmic proteins and the consequent cell death by bacterial lysis.
- Bacteriostatic: once it was believed that chlorhexidine was "only" able to block the replication of bacteria; today we know that he is also able to kill them.
Applications
Chlorhexidine is used in numerous circumstances characterized by a possible or presumed bacterial proliferation; in addition, chlorhexidine-based products are indicated for prophylactic purposes to prevent bacterial infections.
For this purpose, chlorhexidine is indicated for:
- Disinfect the skin after an injury
- Eliminate every possible bacterial trace from the patient's skin before surgery
- Disinfect the doctor's hands before a surgical procedure
- Inhibit or prevent the proliferation of bacteria on the skin
- Support topical treatment for severe acne
- Treat athlete's foot
- Treat dry skin: when combined with substances such as benzalkonium chloride, chlorhexidine is indicated in the prevention and treatment of dry and dry skin associated with dermatitis and eczema
- Preservative (obsolete use of chlorhexidine)
Chlorhexidine for oral rinses
In dentistry, chlorhexidine is part of the formulation of mouthwash, toothpaste and gel with a broad spectrum of action.
Despite being extraordinarily effective against bacteria, chlorhexidine mouthwash should not be used for long periods because, in the long run, it can cause dark or yellow spots on the teeth.
Curiosity
The progressive yellowing of the teeth or the black spots on the dental enamel are the result of a hyperpigmentation of plaque and tartar adhered to the surface of the teeth. To remove this type of stains from the teeth, it is necessary to resort to scaling (professional dental cleaning).
Today, new chlorhexidine formulations have been developed to prevent the formation of teeth stains: it seems that the combination of l-ascorbic acid + sodium metabisulfite + chlorhexidine gluconate is effective to prevent the formation of this unpleasant blemish.
During the entire treatment with chlorhexidine mouthwash, it is recommended to pay particular attention to the concomitant use of toothpaste (and toothbrush). Most toothpastes contain ingredients (in particular sodium lauryl sulfate and sodium monofluorophosphate) capable of altering the therapeutic activity of chlorhexidine. Therefore, to avoid nullifying the effect of the drug, it is strongly recommended to proceed with the usual oral hygiene at a distance of at least 30 minutes to 2 hours from rinsing with chlorhexidine mouthwash.
Skin disinfectant
Chlorhexidine is also indicated for the disinfection of the skin in general and of the hands in particular. Not surprisingly, chlorhexidine products for external use (specific for the hands) are widely used in hospitals. As mentioned, in this area chlorhexidine is widely used to disinfect the skin before surgery and injections to eliminate any possible bacterial trace.
Furthermore, these chlorhexidine-based solutions can also be exploited in the management of patients at home and in nursing homes, both for skin disinfection and for the prevention of bedsores.
Toxicity
When used in appropriate concentrations, chlorhexidine does not have strong irritating or sensitizing properties.
Chlorhexidine digluconate has no oral toxicity since it is poorly absorbed from the gastrointestinal tract. As mentioned, however, improper use of chlorhexidine in the form of mouthwash can cause unpleasant side effects such as burns to the oral mucosa, burning in the mouth and yellow and black spots on the teeth.
In case of allergy or hypersensitivity to chlorhexidine, the typical side effects of an allergic reaction may occur, such as swelling of the face, tongue, hands and feet, respiratory problems, itching, skin irritation and rash. To avoid these unpleasant side effects, it is always recommended to tell the doctor about any allergies (presumed or ascertained) to drugs or other substances.
Chlorhexidine should not be used during neurosurgery surgeries because it is caused by causing neurotoxicity. Similarly, the use of chlorhexidine is strongly discouraged for surgical interventions in the ear: the substance can in fact cause sensorineural deafness.
The use of chlorhexidine as a disinfectant agent is contraindicated near the meninges and in body cavities. When instilled in the eye like eye drops, chlorhexidine (2%) can cause permanent and severe injuries to internal ophthalmic structures.
It is also recommended not to use products containing chlorhexidine in children younger than 2 months.
Interactions
The action of chlorhexidine can be neutralized by anionic or non-ionic agents used to make moisturizing products, neutral soaps or surfactants.
Furthermore, the concomitant use of tobacco / alcohol could cause interactions with the efficacy of chlorhexidine, particularly when used as a mouthwash. For this reason, it is recommended to stop smoking and to avoid alcohol during chlorhexidine therapy.
