Disulfiram inhibits DNA breakage by hydroxyradical-producing agents.

Disulfiram (Antabuse, tetraethylthiuram) inhibits DNA cleavage by 1,2-dimethylhydrazine, ascorbate and cysteine. DNA cleavage by these agents is thought to be caused by hydroxyradicals which are formed during auto-oxidation in the presence of transition metals. H2O2 is an intermediate of these auto-oxidation reactions. The inhibitory action of disulfiram is at the level of hydroxyradical formation from H2O2 or at a later step of the reaction, since DNA cleavage by Fenton's reagent (H2O2/FeCl2) is also inhibited. DNA methylation by N-methyl-N'-nitro-N-nitrosoguanidine or methylazoxymethanolacetate is not affected by disulfiram.