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Key Facts
- Drug Class
- Nitroimidazole antibiotic/antiprotozoal
- Prescription
- Over the counter
- NAFDAC Status
- NAFDAC Registered
- Forms
- Tablet, Suspension, Injection, Suppository
- Price Range
- ₦150 - ₦2,500
- WHO Essential
- Yes
What is Metronidazole?
Metronidazole, universally known as 'Flagyl' across Nigeria, is one of the most commonly used medications in the country. It is a nitroimidazole antibiotic that works against anaerobic bacteria (bacteria that thrive without oxygen) and protozoa (parasitic organisms). Metronidazole enters the bacterial or parasitic cell, where it is converted into active compounds that damage the organism's DNA, ultimately killing it. This dual action against both bacteria and parasites makes it uniquely versatile, and it is a staple medication in virtually every pharmacy, patent medicine store, and hospital in Nigeria.
In Nigerian healthcare and everyday language, 'Flagyl' has become a household name — so widely recognised that many people use it as a general term for any medication taken for stomach problems, diarrhoea, or 'running stomach.' It is prescribed and sold for a huge range of conditions, from amoebic dysentery and giardiasis to dental infections, vaginal infections, and as part of combination therapy for peptic ulcer disease caused by Helicobacter pylori. The 400mg tablet is the most commonly used form, though it is also available as a suspension for children, as suppositories, and as an intravenous injection for hospital use.
While metronidazole is relatively safe and effective when used correctly, its widespread availability as an over-the-counter medication in Nigeria means it is frequently misused. Many people take it for any type of diarrhoea or stomach discomfort, even though it is not effective against viral diarrhoea or non-infective causes of abdominal pain. The drug is also notable for its strong interaction with alcohol — consuming any amount of alcohol while taking metronidazole or for at least 48 hours afterwards can cause severe nausea, vomiting, flushing, and rapid heartbeat (disulfiram-like reaction). This is one of the most important warnings that every patient in Nigeria should be aware of before taking this medication.
What is Metronidazole used for?
In Nigeria, Metronidazole is commonly used for:
- Amoebic dysentery (intestinal amoebiasis) — one of the most common reasons for use in Nigeria
- Amoebic liver abscess
- Giardiasis (Giardia lamblia infection) — common in areas with poor water quality
- Trichomoniasis — a sexually transmitted infection
- Bacterial vaginosis
- Anaerobic bacterial infections — including intra-abdominal infections, pelvic infections, and wound infections
- Dental infections and periodontal abscesses — often used in combination with amoxicillin
- Helicobacter pylori eradication — as part of triple therapy for peptic ulcer disease (with amoxicillin and a proton pump inhibitor)
- Pseudomembranous colitis (Clostridium difficile infection)
- Surgical prophylaxis — particularly for abdominal and gynaecological surgeries
Dosage
IMPORTANT
Always follow your doctor's or pharmacist's instructions. The information below is for general reference only.
Adults
The standard adult dose varies by condition. For amoebic dysentery: 400mg to 800mg three times daily for 5 to 10 days. For giardiasis: 400mg three times daily for 5 days, or a single 2g dose. For trichomoniasis and bacterial vaginosis: 400mg twice daily for 7 days, or a single 2g dose. For anaerobic infections: 400mg three times daily for 7 to 10 days. For dental infections: 200mg to 400mg three times daily for 3 to 7 days. For H. pylori eradication: 400mg twice daily for 7 to 14 days (as part of combination therapy). Tablets should be taken with or after food to minimise stomach irritation.
Children
Paediatric dosage is based on body weight. The usual dose is 7.5mg per kilogram three times daily. For amoebic dysentery in children, the dose may be increased. Metronidazole suspension (200mg/5ml) is available for children who cannot swallow tablets. Always use the measuring device provided — do not estimate with household spoons. Shake the suspension well before each dose.
Elderly
Elderly patients generally receive the same doses as younger adults for short courses. However, for prolonged treatment, lower doses or longer intervals between doses may be considered, especially in those with liver impairment, as metronidazole is primarily metabolised by the liver.
STRICTLY AVOID ALCOHOL during treatment and for at least 48 hours after completing the course. Taking alcohol with metronidazole causes a severe disulfiram-like reaction with intense nausea, vomiting, abdominal cramps, and flushing. Swallow tablets with a full glass of water. The metallic taste in the mouth is a common and harmless side effect — it will go away after you finish the course.
Side Effects
Common side effects
- •Metallic or bitter taste in the mouth — this is the most characteristic side effect and is experienced by most patients
- •Nausea and loss of appetite
- •Stomach pain and cramping
- •Diarrhoea
- •Headache and dizziness
- •Dark or reddish-brown discolouration of urine — this is harmless and caused by a metabolite of the drug
Serious side effects — seek medical help immediately
- Peripheral neuropathy — numbness, tingling, or pain in the hands and feet, especially with prolonged use or high doses. This may be irreversible if the drug is not stopped promptly.
- Central nervous system effects — seizures, confusion, encephalopathy (brain dysfunction), particularly with high doses or prolonged courses
- Severe disulfiram-like reaction with alcohol — intense nausea, vomiting, flushing, rapid heartbeat, low blood pressure
- Blood disorders — very rare, but includes neutropenia (low white blood cell count)
- Severe allergic reaction — skin rash, swelling, difficulty breathing
When to see a doctor
Seek medical attention if you experience numbness or tingling in your hands or feet (this may indicate nerve damage that could be permanent if the drug is continued), seizures, severe confusion, persistent or worsening diarrhoea, or signs of a severe allergic reaction such as swelling or difficulty breathing. If you accidentally consume alcohol while taking metronidazole and develop severe vomiting, chest pain, or difficulty breathing, go to the nearest hospital immediately. In Nigeria, the emergency units of general hospitals and teaching hospitals can manage these reactions.
Warnings & Precautions
Do not take Metronidazole if you have:
- Known allergy to metronidazole or other nitroimidazole drugs (tinidazole, secnidazole)
- Active neurological disorders, especially peripheral neuropathy
- First trimester of pregnancy (relative contraindication — see pregnancy section)
- Severe liver disease (metronidazole clearance is significantly reduced)
Drug interactions
- •Alcohol — causes a severe disulfiram-like reaction with nausea, vomiting, flushing, and rapid heartbeat. Avoid completely during treatment and for 48 hours after the last dose.
- •Warfarin — metronidazole significantly enhances the anticoagulant effect. INR must be monitored closely and warfarin dose adjusted.
- •Lithium — metronidazole can increase lithium levels to toxic concentrations
- •Phenytoin and phenobarbital — these drugs speed up metronidazole metabolism, potentially reducing its effectiveness
- •Disulfiram — do not use together; risk of psychotic reactions and confusion
- •Busulfan — metronidazole can increase busulfan toxicity
- •5-Fluorouracil — metronidazole can reduce clearance and increase toxicity
Pregnancy & Breastfeeding
Metronidazole is generally avoided during the first trimester of pregnancy due to theoretical concerns about effects on the developing foetus, although large studies have not conclusively shown harm. In the second and third trimesters, it may be used when clearly needed — for example, for symptomatic trichomoniasis or amoebic dysentery that cannot wait until after delivery. Metronidazole passes into breast milk and may give it a bitter taste, potentially causing the baby to refuse feeds temporarily. Some guidelines recommend expressing and discarding breast milk during treatment and for 24 hours after the last dose. Always consult your doctor or midwife before using metronidazole during pregnancy or while breastfeeding.
NAFDAC-Registered Brands of Metronidazole in Nigeria
4 brands registered with NAFDAC as of 2026-02-01.
| Brand Name | Manufacturer | Strength | Form | NAFDAC Reg. No. |
|---|---|---|---|---|
| Flagyl | Sanofi | 200mg, 400mg | Tablet | A4-0345 |
| Metro | Emzor | 400mg | Tablet | A4-5432 |
| Torgyl | May & Baker | 200mg, 400mg | Tablet | A4-6543 |
| Flagyl Suspension | Sanofi | 200mg/5ml | Suspension | A4-0346 |
How to Verify Your Metronidazole is Genuine
- 1Check for a valid NAFDAC registration number on the packaging of all metronidazole products.
- 2Use the NAFDAC Mobile Authentication Service (MAS): scratch the verification panel and send the code to 38353 to verify the product.
- 3Purchase from registered pharmacies and licensed patent medicine stores. While metronidazole is widely available even at market stalls, buying from verified outlets reduces the risk of substandard products.
- 4Check the packaging for clear printing, correct spelling, intact seals, and proper batch number and expiry date information.
- 5Compare packaging with known genuine products — counterfeit Flagyl has been seized by NAFDAC in the past.
- 6If a pack of metronidazole costs significantly below ₦150, be cautious about its quality and source.
Metronidazole Price in Nigeria
Metronidazole prices in Nigeria typically range from ₦150 to ₦2,500 per pack, depending on the brand, strength, and where you buy it.
₦150 – ₦2,500
per pack
Prices vary by location and vendor. Last updated: 2026-02-01
Where to Buy
Purchase Metronidazole only from licensed pharmacies and verified distributors. Avoid buying medicines from unverified sources, roadside vendors, or unregistered market stalls.
Frequently Asked Questions
Sources
- •NAFDAC Greenbook — National Agency for Food and Drug Administration and Control registered products database
- •WHO Model List of Essential Medicines (23rd List, 2023)
- •British National Formulary (BNF)
- •Nigerian Standard Treatment Guidelines