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Nitroimidazole antibioticPrescription only · Schedule H

Metronidazole

Uses, side effects, interactions and warnings

Reviewed by Dr. Priya Deshmukh, Venereology & Leprosy) · Updated
Generic nameMetronidazole
Drug classNitroimidazole antibiotic
FormTablet or vaginal gel
PrescriptionRequired
Starts working2–3 days for symptom relief
Quick answer

Metronidazole is a prescription antibiotic used to treat bacterial vaginosis and trichomoniasis, two common causes of abnormal vaginal discharge. It comes as tablets or a vaginal gel. Avoid alcohol during treatment and for 2 days after, as the combination can cause severe nausea and vomiting.

What is metronidazole used for?

  • Bacterial vaginosis
  • Trichomoniasis (an STI; partners need treatment too)
  • Some gut and dental infections

How does metronidazole work?

Metronidazole enters bacteria and parasites that live without oxygen and damages their DNA, which kills them.

How is metronidazole used?

Tablets are commonly taken twice a day for 7 days, or as a single larger dose for some infections. Vaginal gel is used once a day for 5 days. Your doctor will decide the course. Finish it even if you feel better.

What are the side effects of metronidazole?

Common
  • Metallic taste
  • Nausea
  • Loss of appetite
  • Dark urine
  • Headache
Get medical help right away
  • Numbness or tingling in hands or feet
  • Seizures or confusion
  • Severe skin rash
  • Severe diarrhoea

Which medicines interact with metronidazole?

AlcoholAvoidCauses flushing, vomiting and a racing heart. Avoid during treatment and for 48 hours after.
DisulfiramAvoidRisk of confusion and psychosis.
WarfarinCautionIncreases bleeding risk; INR checks needed.
LithiumCautionLithium levels may rise.

Who should be careful with metronidazole?

Tell your doctor if you are pregnant or breastfeeding, have liver disease, a blood disorder or a nerve condition. For trichomoniasis, sexual partners should be treated at the same time and you should avoid sex until both have finished treatment.

Frequently asked questions

Do men need treatment for bacterial vaginosis?

No. Male partners do not need treatment for BV, but they do for trichomoniasis.

Why can’t I drink alcohol with metronidazole?

The combination causes a reaction with flushing, vomiting and palpitations. Wait at least 48 hours after the last dose.

Why does BV keep coming back?

BV returns in many women within months. Your doctor may suggest a longer course or preventive treatment.

This information does not replace advice from your doctor or pharmacist. SexologistIndia.com does not sell medicines.