What it is used for
- Certain dental and gum infections
- Some gut and abdominal infections
- Bacterial vaginosis and some other vaginal infections
- Some skin infections, including rosacea (as a gel or cream)
- Certain parasite infections such as giardiasis
- Some infections after surgery
How it works
Metronidazole works against certain bacteria that grow without oxygen and against some parasites. It damages the genetic material inside these organisms so they cannot survive. It does not work against ordinary viruses or all types of bacteria.
How it is taken
Comes as tablets, a liquid, a vaginal gel, a skin gel or cream, and an injection in hospital. Take or use it exactly as your doctor or pharmacist directs and follow the label. Swallow tablets with water, often with or after food. Complete the course as advised.
No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.
Common side effects
- Nausea
- A metallic taste in the mouth
- Loss of appetite
- Stomach upset
- Headache
- Dark-coloured urine (harmless)
Serious effects — get help
- Severe allergic reaction with swelling or breathing difficulty
- Numbness, tingling or weakness in the hands or feet (possible nerve effect)
- Severe headache, confusion, unsteadiness or seizures
- Severe, persistent or bloody diarrhoea
- Yellowing of the skin or eyes
If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.
Interactions to watch
- Alcohol and products containing alcohol (can cause a strong reaction with flushing, nausea and a fast heartbeat)
- Blood thinners such as warfarin
- Lithium
- Phenytoin
- Some medicines processed by the liver
- Disulfiram
Who should take care
- Avoid alcohol while taking it and for the time afterwards advised by your clinician, as the combination can make you very unwell
- Tell your clinician if you have liver problems or a nervous system condition
- Discuss pregnancy or breastfeeding with your doctor or pharmacist
- Mention all other medicines you take
- Use the full course even if symptoms ease