Like all medicines, terbinafine can cause side effects, although not everyone gets them.
Side effects usually go away when you stop using or taking the medicine.
Common side effects
This common side effect of terbinafine cream, gel, spray or solution happens in more than 1 in 100 people. There are things you can do to help cope:
Peeling or itching skin
If you're using the cream, gel or spray, try using smaller amounts or stop using it completely. Avoid clothes that irritate your skin, such as wool or synthetic fabrics. If the rash is itchy, pat or tap the area rather than scratching.
It may help to take an antihistamine, which you can buy from a pharmacy. Check with the pharmacist to see what type is suitable for you.
These common side effects of terbinafine tablets happen in more than 1 in 100 people. There are things you can do to help cope with them:
Rash
Avoid clothes that irritate your skin, such as wool or synthetic fabrics. If the rash is itchy, pat or tap the area rather than scratching.
It may help to take an antihistamine, which you can buy from a pharmacy. Check with the pharmacist to see what type is suitable for you.
Headache
Rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend a painkiller if you need one.
Talk to your doctor if the headaches last longer than a week or are severe.
Diarrhoea
Drink lots of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee. Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.
If you take contraceptive pills 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. If you're being sick, try small, frequent sips of water to avoid dehydration. It might help to take your tablets after a meal or snack.
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.
A smaller appetite than usual
Your appetite should get better as your body gets used to the medicine. It may also help to eat smaller and more frequent meals and to eat foods you really enjoy.
If your appetite does not improve or you lose a lot of weight, ask your doctor for advice.
Losing your sense of taste
This usually gets better gradually after you stop taking terbinafine. Speak to a doctor if it does not get better.
Stomach ache
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.
Indigestion
Try not to drink too much alcohol or drinks containing caffeine, such as tea, coffee, cola or energy drinks. Avoid rich, spicy or fatty foods.
If indigestion bothers you mostly at night, stop eating 3 to 4 hours before your bedtime, and try propping your head and shoulders up in bed.
Ask a pharmacist to recommend an antacid.
Muscle or joint pain
Ask a pharmacist to recommend a painkiller if you need one. Talk to your doctor if the pain lasts longer than a week or is severe.
Feeling dizzy
Stop what you're doing and sit or lie down until you feel better. Do not drive, cycle or use tools or machinery if you're feeling dizzy.
Problems with your eyesight
Talk to your doctor if this bothers you.
Talk to your pharmacist or doctor if the advice on how to cope does not help and these side effects bother you or do not go away.
Serious side effects
Some people can have serious side effects when using or taking terbinafine. These happen in less than 1 in 1,000 people.
If you're prescribed tablets, stop taking them and 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 high temperature with a rash, itchy skin and unusual tiredness, or if you notice any purple spots under your skin – these can be signs of an inflammation of the blood vessels called vasculitis
- you get severe pain near the top of your stomach that spreads to your back – this can be a sign of an inflamed pancreas (acute pancreatitis)
- your muscles feel weak or painful, or your pee is a dark red-brown – these can be signs of muscle problems
Serious allergic reaction
It happens rarely but it is possible to have a serious allergic reaction (anaphylaxis) to terbinafine.
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.
Long-term side effects
If you take terbinafine tablets for a long time, there's a small chance that they can affect your liver. This happens to less than 1 in 1,000 people. Your doctor may ask you to have a blood test to check that your liver is working properly.
Other side effects
These are not all the side effects of terbinafine. 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.