Benzalkonium Chloride: Failures as an Antiseptic

Abstract

An old story tells of a man who bought a mule that would not obey commands, no matter how vehemently they were given. When the mule's former owner was consulted, he advised the purchaser that it was first necessary to get the mule's attention for which a sharp blow to the head by a stout two-by-four was needed. An analogy is found in this issue ofThe Journalregarding the use of quaternary ammonium compounds as antiseptics. Among these agents, benzalkonium chloride has had continued use despite repeated warnings about its possible ineffectiveness. For example, the second edition of AMA Drug Evaluations 1 warns that Gram-negative organisms ( Pseudomonas ) are more resistant to quaternary ammonium compounds; that the compounds tend to be deposited on the skin as a film that is sterile on the outside but under which bacteria may remain alive; that they are inactivated by soaps, inorganic matter, and