About Metronidazole A nitroimidazole antibiotic, Anti-infective, Antiprotozoal,amebicide. Mechanism of Action of Metronidazole Metronidazole is nitro imidazoles which have broad spectrum cidal activity against Protozoa and some anaerobic bacteria. Its selective toxicity to anaerobic microbes involves 1. Drug enters the cell by diffusion, 2. Nitro group of drug is reduced by redox proteins present only in anaerobic organisms to reactive nitro radical which exerts cytotoxic action by damaging DNA and other critical biomolecules. 3. DNA helix destabilization & strand breakage has been observed. Interactions for Metronidazole Warfarin & other coumarin anticoagulants: Potentiates the anticoagulant effect resulting in increased prothrombin time. Alcohol: A disulfiram-like reaction. Abdominal cramps, nausea, vomiting, headache & flushing. Disulfiram: Acute psychotic reaction or confusional state. Phenobarbital & Phenytoin: Increased metabolism of metronidazole resulting in decrease