The two alcohols most frequently used for antisepsis and disinfection are ethanol and isopropyl alcohol (isopropanol). They are rapidly active, killing vegetative bacteria, Mycobacterium tuberculosis, and many fungi, and inactivating lipophilic viruses. The optimum bactericidal concentration is 60–90% by volume in water. They probably act by denaturation of proteins. They are not used as sterilants because they are not sporicidal, do not penetrate protein-containing organic material, may not be active against hydrophilic viruses, and lack residual action because they evaporate completely. The alcohols are useful in situations in which sinks with running water are not available for washing with soap and water. Their skin-drying effect can be partially alleviated by addition of emollients to the formulation. Use of alcohol-based hand rubs has been shown to reduce transmission of health care-associated bacte-rial pathogens and is recommended by the Centers for Disease Control and Prevention (CDC) as the preferred method of hand decontamination. Alcohol-based hand rubs are ineffective against spores of C difficile, and assiduous handwashing with soap and water is still required for decontamination after caring for a patient with infection from this organism.
Alcohols are flammable and must be stored in cool, well-ventilated areas. They must be allowed to evaporate before cau-tery, electrosurgery, or laser surgery. Alcohols may be damaging if applied directly to corneal tissue. Therefore, instruments such as tonometers that have been disinfected in alcohol should be rinsed with sterile water, or the alcohol should be allowed to evaporate before they are used.