Like all medicines, fluconazole can cause side effects, although not everyone gets them.
Common side effects
These common side effects of fluconazole happen in more than 1 in 100 people. There are things you can do to help cope with them:
Headache
Rest and drink plenty of fluids. Do not drink too much alcohol. Ask a pharmacist to recommend a painkiller if you need one.
Talk to your doctor if the headaches last longer than a week or are severe.
Stomach pain
Try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your stomach may also help.
If you're in a lot of pain, speak to a doctor or pharmacist.
Diarrhoea
Drink lots of fluids, such as water or squash, to avoid dehydration. Speak to a pharmacist if you have signs of dehydration, such as peeing less than usual or having strong-smelling pee. Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.
If you take the combined contraceptive pill or the progestogen-only pill and you have severe diarrhoea for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet for advice.
Feeling or being sick (nausea or vomiting)
Stick to simple meals and do not eat rich or spicy food. It might help to take your fluconazole after a meal or snack.
If you're being sick, try small, frequent sips of water to avoid dehydration. Signs of dehydration include peeing less than usual or having strong-smelling pee.
If you take the combined contraceptive pill or the progestogen-only pill and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.
Rash
It may help to take an antihistamine, which you can buy from a pharmacy. Check with the pharmacist to see what type is right for you.
If the rash gets worse, or does not get better, speak to your doctor.
Speak to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.
Serious side effects
Serious side effects are uncommon and happen in less than 1 in 100 people.
Call a doctor or call 111 immediately if:
- the whites of your eyes turn yellow, or your skin turns yellow although this may be less obvious on brown or black skin, or if you have pale poo and dark pee – these can be signs of liver problems
- you bruise more easily or get infections more easily – these can be signs of a blood disorder
- you have a faster or irregular heartbeat
Serious allergic reaction
It happens rarely but it's possible to have a serious allergic reaction (anaphylaxis) to fluconazole.
Immediate action required: 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.
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Other side effects
These are not all the side effects of fluconazole. For a full list, see the leaflet inside your medicine 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.