Lack of mutagenicity of nifedipine: a possible metabolic implication.

Nifedipine, being a nitro aromatic compound, is capable of undergoing reduction via hydroxyl-amino intermediate to an amine. Such an intermediate is a mutagenic culprit. The urinary metabolites of nifedipine were investigated in order to allay the fear of the existence of this metabolic route in humans. Nifedipine (20 mg) was administered twice daily for 2 weeks. No nitro-reduction product was detected over a 1-month period. Nifedipine lacks mutagenicity in the absence or presence of drug metabolizing microsomes in Salmonella typhimurium TA 98 and Salmonella typhimurium TA 100.