An active amide group in the molecule of drugs that induce pemphigus: a casual or causal relationship?

Traditionally, drugs that are capable of inducing pemphigus are divided into two main groups according to their chemical structure, in particular, the existence of a sulfhydryl group in their molecule. Thus, two groups are formed: (1) drugs containing a sulfhydryl radical (thiol drugs or SH drugs) and (2) nonthiol or other drugs. Much emphasis has been put on the role of the sulfhydryl group in the pathogenesis of drug-induced pemphigus. The effects of this group have been extensively studied, and a logical paradigm on the mode of its action has been created. However, no attempt has been made to search for other biochemical radicals which might have an influence on the activation/triggering of this disease. The aim of the present report is to draw attention to a chemical group common to the molecule of several drugs that have been associated with the induction of pemphigus. Careful analysis of the chemical structure of nonthiol drugs known to induce pemphigus revealed that several of them share an active amide group in their molecule. We believe that this group might be responsible for the induction of the disease; thus, a third group of drugs capable of triggering pemphigus can be formed, namely drugs containing an active amide group. Several drugs of this group are discussed.