Side effects of trimethoprim

These common side effects of trimethoprim happen to more than 1 in 100 people. There are things you can do to help cope with them:

It may help to use an emollient cream or gentle, fragrance-free moisturising cream, or take an antihistamine, which you can buy from a pharmacy. Check with a pharmacist to see what may be suitable for you.

Try taking trimethoprim with or after food to see if that helps your symptoms. It may also help if you stick to simple meals and avoid rich or spicy food while you're taking this medicine.

If you're being sick, try small frequent sips of water to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.

If you take the combined contraceptive pill or progestogen-only pill and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet to find out what to do.

Drink lots of water or squash to avoid dehydration. Speak to a doctor or pharmacist if you have signs of dehydration such as 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 the combined contraceptive pill or progestogen-only pill and you have severe, watery diarrhoea or any diarrhoea that lasts for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet to find out what to do.

Trimethoprim can sometimes cause the infection, thrush. Drying properly after washing, wearing cotton underwear and avoiding sex until it's cleared up can help.

Make sure you rest and drink plenty of fluids. It's best not to drink too much alcohol. Everyday painkillers, such as paracetamol and ibuprofen, are safe to take with trimethoprim. Speak to your doctor if these do not help or the headaches are severe and do not go away.

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.