Nimorazole is a synthetic nitroimidazole derivative with potent antiprotozoal and antibacterial activity, primarily used in the treatment of amoebiasis, giardiasis, and bacterial vaginosis. It acts as a prodrug, requiring intracellular reduction of its nitro group to generate cytotoxic intermediates that damage microbial DNA. In the Indian context, it is a second-line or alternative therapy, particularly useful in cases of metronidazole intolerance or resistance.
Adult: Amoebiasis/Giardiasis: 1g (two 500mg tablets) twice daily for 5-10 days. Bacterial Vaginosis/Trichomoniasis: 2g (four 500mg tablets) as a single dose or 1g twice daily for 2 days.
Note: To be taken orally after meals to minimize gastrointestinal upset. Tablets should be swallowed whole with a full glass of water. For single-dose regimens for vaginosis, all tablets should be taken together.
Nimorazole is a prodrug. Its nitro group is reduced by low-redox potential electron transport proteins (e.g., ferredoxin) found in anaerobic bacteria and protozoa. This reduction generates short-lived, cytotoxic nitro radical anions and other reactive species. These intermediates cause strand breaks in microbial DNA, inhibit nucleic acid synthesis, and lead to cell death.
Pregnancy: Category C (US FDA). Contraindicated in the first trimester. Avoid in second and third trimesters unless potential benefit justifies potential risk to the fetus. Teratogenic in some animal studies.
Driving: May cause dizziness, vertigo, or visual disturbances. Patients should be cautioned about operating machinery or driving until they are certain nimorazole does not affect them adversely.
| Alcohol (Ethanol) | Disulfiram-like reaction (flushing, palpitations, nausea, vomiting). | Major |
| Warfarin and other Coumarin anticoagulants | Nimorazole may potentiate anticoagulant effect, increasing INR and risk of bleeding. | Major |
| Lithium | May decrease lithium clearance, increasing risk of lithium toxicity. | Moderate |
| Phenytoin, Phenobarbital | Potential for decreased nimorazole efficacy due to enzyme induction. | Moderate |
| Cyclosporine, Tacrolimus | Potential increase in immunosuppressant levels, increasing risk of nephrotoxicity. | Moderate |
| 5-Fluorouracil (5-FU) | Nimorazole may enhance the toxicity of 5-FU. | Moderate |
Same composition (Nimorazole (500mg)), different brands: