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ANTIPARASITIC PRODUCTS, INSECTICIDES AND REPELLENTS › ANTIPROTOZOALS › AGENTS AGAINST AMOEBIASIS AND OTHER PROTOZOAL DISEASES › Nitroimidazole derivatives
ornidazole
P01AB03
Forms & Strengths
- Tablet: 500 mg
- Infusion: 500 mg/100 mL
Adult Dosing
- Amebic dysentery: 500 mg orally twice daily for 5 to 7 days
- Hepatic amebiasis: 500 mg orally twice daily for 5 days
- Trichomoniasis: 1.5 g as a single oral dose or 500 mg twice daily for 5 days
- Bacterial vaginosis: 1.5 g as a single oral dose
- Anaerobic infections: 500 mg IV every 12 hours
Pediatric Dosing
- Amebiasis (children > 2 months): 25 mg/kg/day orally in divided doses for 5 to 7 days
- Anaerobic infections: 10 mg/kg IV every 12 hours
Indications
- Treatment of susceptible protozoal infections (amoebiasis, giardiasis, trichomoniasis)
- Treatment of bacterial vaginosis
- Prophylaxis and treatment of anaerobic bacterial infections
Mechanism of Action
- Nitroimidazole derivative
- Enters microbial cells and undergoes reduction by nitroreductase to form reactive radical species
- Damages microbial DNA, inhibiting nucleic acid synthesis and leading to cell death
Contraindications
- Hypersensitivity to ornidazole or other nitroimidazole derivatives
- First trimester of pregnancy (for trichomoniasis)
- Active central nervous system diseases or blood dyscrasias
Adverse Reactions
- Common: Nausea, vomiting, metallic taste, dry mouth, dizziness, fatigue
- Serious: Peripheral neuropathy, convulsions, leukopenia, hypersensitivity reactions
Drug Interactions
- Enhances the anticoagulant effect of coumarin-type oral anticoagulants (e.g., warfarin)
- Disulfiram-like reaction may occur with alcohol consumption
- Enzyme inducers (e.g., phenytoin, phenobarbital) may increase elimination of ornidazole
Curated Content: Needs Vetting Before Put to Clinical Use