Mechanism of decomposition of N-hydroxyacetaminophen, a postulated toxic metabolite of acetaminophen

Abstract

The decomposition of N-hydroxyactaminophen (N-acetyl-N-hydroxy-p-aminophenol), a postulated toxic metabolite of acetaminophen (N-acetyl-p-aminophenol) in aqueous solution is quantitatively accounted for by the appearance of equimolar amounts of p-nitrosophenol and acetaminophen. The decomposition rate depends on initial concentration and varies with pH. Antioxidants decrease the rate of decomposition and change the products. In the presence of cysteine, N-acetyl-3-(S-cysteine)-p-aminophenol, an in vivo metabolite of acetaminophen, is a product of decomposition.