Toxicity Profile for Benzocaine (1992)

Abstract

Benzocaine is a skin sensitizer in man and rodents and has also caused photosensitization reactions. Fairly high concentrations produced only slight irritation on guinea-pig skin although the hydrochloride salt is reportedly a skin and eye irritant in man. Benzocaine's local anaesthetic properties have found widespread use in various medical applications. In man, the ingestion of benzocaine has resulted in a serious blood disorder, methaemoglobinaemia, which results in a poor oxygen supply to the tissues. A similar effect has been produced following its application to the oral/respiratory membranes or to skin. Methaemoglobinaemia has also been induced in rats treated orally. Inconsistent results have been reported in Ames mutagenicity assays, and in other limited bacterial studies, benzocaine was not mutagenic and did not induce DNA damage.