Side Effects Of Metronidazole

Like all medicines, metronidazole can cause side effects, although not everyone gets them.

Do not drink alcohol while taking metronidazole tablets or liquid or using the suppositories. Metronidazole can react with alcohol to cause side effects such as feeling or being sick, stomach pain, hot flushes, difficulty breathing and a pounding heartbeat (palpitations).

After finishing your treatment, wait for 2 days before drinking alcohol again. This allows the metronidazole to leave your body.

Common side effects of metronidazole

There are things you can do to help cope with these common side effects of metronidazole.

Talk to your doctor or pharmacist if this advice does not help and a side effect bothers you or does not go away.

Serious side effects of tablets, liquid, suppositories or vaginal gel

Serious side effects are rare and happen in less than 1 in 1,000 people.

Stop taking metronidazole and call a doctor or call 111 now if:

• the whites of your eyes turn yellow, or your skin turns yellow (this may be less obvious on brown or black skin) - these can be signs of liver or gallbladder problems
• you get unexpected infections, mouth ulcers, bruising, bleeding gums, or extreme tiredness - these can be caused by a blood problem
• you have bad stomach pains which may reach through to your back - this can be a sign of pancreatitis
• you have blurred vision or double vision

Call 999 or go to A&E if:

Do not drive to A&E. Ask someone to drive you or call 999 and ask for an ambulance.

Bring all the medicines you take with you.

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to metronidazole.

Call 999 now if:

• your lips, mouth, throat or tongue suddenly become swollen
• you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
• your throat feels tight or you're struggling to swallow
• your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
• you suddenly become very confused, drowsy or dizzy
• someone faints and cannot be woken up
• a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)

You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.

These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

Other side effects

These are not all the side effects of metronidazole tablets, liquid, cream, gel, suppositories or vaginal gel. For a full list see the leaflet inside your medicines packet.

Reporting side effects

You can report any suspected side effect using the Yellow Card safety scheme.

Visit the Yellow Card website for more information about reporting side effects.

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