Metronidazole Oral: Dosing, Duration, and Precautions
Metronidazole guidance for protozoal and anaerobic infections, with indication-specific schedules and alcohol precautions.
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source date listed on the source page
Guide category
Oral drugs
Safety boundary
Prescription medicine information for clinician-guided use.
Kenza Health Hub presents this medicine page as structured health education. Check dose, route, interactions, pregnancy or breast-feeding considerations, and local protocol with a qualified clinician or pharmacist. Read our medical editorial policy.
Therapeutic action
Antiprotozoal, antibacterial (group of nitroimidazoles).
Indications
- Amoebiasis, giardiasis, trichomoniasis.
- Bacterial vaginitis and infections due to anaerobic bacteria.
Forms and strengths
- 250 mg and 500 mg tablets.
- 200 mg/5 ml oral suspension.
Dose and duration
Amoebiasis
The treatment lasts 5 days in intestinal amoebiasis and 5 to 10 days in hepatic amoebiasis.
- Child: 15 mg/kg 3 times daily.
- Adult: 500 mg 3 times daily.
Giardiasis
- Child: 30 mg/kg once daily for 3 days.
- Adult: 2 g once daily for 3 days.
Trichomoniasis and bacterial vaginitis
In the event of trichomoniasis, also treat the sexual partner.
- Adult: 2 g single dose.
Infections due to anaerobic bacteria
According to indication, metronidazole may be used in combination with other antibacterials; treatment duration depends on indication.
- Child: 10 mg/kg 3 times daily.
- Adult: 500 mg 3 times daily.
Contra-indications, adverse effects, precautions
- Do not administer to patients with hypersensitivity to metronidazole or another nitroimidazole.
- May cause gastrointestinal disturbances and rarely allergic reactions, brownish urine, headache, and dizziness.
- There is a risk of antabuse reaction when combined with alcohol.
- Administer with caution in patients taking oral anticoagulants, lithium, phenytoin, or ergometrine.
- Reduce the total daily dose to one third and give once daily in patients with severe hepatic impairment.
- Pregnancy: no contra-indication; divide into smaller doses and avoid prolonged use.
- Breast-feeding: significantly excreted in milk; divide into smaller doses and avoid prolonged use.
Source
MSF Essential drugs practical guidelines (January 2026)
This page combines source-derived medicine reference sections with Kenza editorial context, while leaving out the Storage and Remarks sections from the source batch.
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