Metronidazole
Covers anaerobes and protozoa. Used for intra-abdominal infection, amoebiasis, giardia, C. difficile, dental and pelvic infections.
Common brands in Pakistan: Flagyl. Brand availability changes; check with your pharmacy.
On this page
Uses
- Intra-abdominal and pelvic infection (with a cephalosporin).
- Amoebic dysentery and amoebic liver abscess (followed by a luminal agent).
- Giardiasis.
- C. difficile (mild, if vancomycin unavailable).
- Dental infections, bacterial vaginosis, trichomoniasis.
Adult dose
| Indication | Dose |
|---|---|
| Anaerobic infection (IV) | 500 mg IV every 8 hours |
| Anaerobic infection (oral) | 400 mg 3 times daily (or 500 mg every 8 hours) |
| Amoebic dysentery or liver abscess | 400–800 mg 3 times daily for 5–10 days, then diloxanide |
| Giardiasis | 400 mg 3 times daily for 5 days (or 2 g daily for 3 days) |
| Bacterial vaginosis | 400 mg twice daily for 7 days |
Children's dose
7.5 mg/kg 3 times daily (amoebiasis 10–15 mg/kg 3 times daily, max 800 mg per dose).
Kidney and liver
Reduce in severe liver disease.
Pregnancy and breastfeeding
Can be used when needed; avoid high single doses.
Side effects and cautions
- Metallic taste, nausea.
- No alcohol during and for 48 hours after (disulfiram-like reaction).
- Peripheral neuropathy with long courses; interacts with warfarin.
Frequently asked questions
What is the metronidazole dose for amoebic dysentery?
400–800 mg three times a day for 5–10 days, followed by a luminal agent such as diloxanide.
Can you drink alcohol with metronidazole?
No. Avoid alcohol during treatment and for 48 hours after.
Used in these guides
Sources
Doses on this page are typical doses from the sources above. Always confirm with a current drug reference, the product leaflet and your hospital protocol, especially in children, pregnancy and kidney or liver disease.
For FCPS Part 1
Revising for FCPS Part 1? Metronidazole is covered in our textbook chapter Antimicrobials in pregnancy, with practice MCQs.