Chlorhexidine is a broad-spectrum antiseptic that is considered to have rapid action, residual activity and is active in the presence of organic matter. The positive charge carried by the chlorhexidine molecule reacts with the cell surface of bacteria which is negatively charged and destroys the cell membrane. It is effective on both gram-positive and gram-negative bacteria, although it is less effective with some gram-negative bacteria. It has also shown to have some virucidal efficacy and to inhibit spores and fungi. Depending on the level of kill (e.g. sanitizing vs. disinfection), Chlorhexidine is effective in contact times of 30-seconds to 2 minutes against vegetative bacteria.
Chlorhexidine is non-flammable. At high concentrations Chlorhexidine is harmful, however at the low concentrations typically used for oral rinses and skin cleaners it can be safely used. Despite Chlorhexidine being relatively non-toxic at low concentrations, there have been incidences of anaphylactic reactions. In fact, in the UK, a patient safety alert on the risk of anaphylactic reactions from the use of medical devices and medicinal products containing chlorhexidine has been issued with recommendations that if a patient experienced an unexplained reaction that healthcare providers check whether chlorhexidine was used or was impregnated in a medical device that was used.
From an environmental perspective, the by-products that chlorhexidine degrades into are reported to be more toxic that chlorhexidine itself. Further, chlorhexidine can accumulate in the bodies of aquatic creatures and thus increases the toxic effects caused by long-term exposure.
Here’s how we would score Chlorhexidine on the key decision making criteria:
• Speed of Disinfection – A to B
o Contact times will be dependent upon concentration and level of kill required and range from 30 seconds to 2 minutes
• Spectrum of Kill – B to C
o Achieves disinfection against all microorganisms; bacteria, viruses and fungi but efficacy is concentration dependent
• Cleaning Effectiveness – C
o Some cleaning studies have shown that Chlorhexidine is not an effective cleaning agent
• Safety Profile – B
o Is considered safe to humans at the concentrations used for oral rinses and skin cleaners
o Anaphylactic reactions are well documented
• Environmental Profile – D
o Bioaccumulative in the environment and reacts to form more toxic by-products
o Concerns with Aquatic Toxicity
• Cost Effectiveness – B to C
o Products are available from a number of suppliers
**For more in-depth scientific information about Alcohol and other disinfectant chemistries, stay tuned to www.infectionpreventionresource.com.