Side effects of valproic acid

These common side effects of valproic acid may happen in more than 1 in 100 people. They're usually mild and go away by themselves. There are things you can do to help cope with them:

This is most likely when you start treatment.

It usually helps if you take valproic acid with or after a meal or snack.

It may also help if you avoid rich or spicy food. Take small, frequent sips of water if you're being sick 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 for advice.

Drink plenty 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 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 for advice.

For a dry mouth, try sugar-free gum or sweets, or sipping cold drinks. If this does not help, or you have mouth ulcers, talk to your pharmacist or doctor.

If you're bothered by swollen gums or this symptom does not go away, talk to your doctor or dentist.

As your body gets used to valproic acid, these side effects should wear off.

If these symptoms do not get better within a week or 2, your doctor may either reduce your dose or increase it more slowly. If that does not work, talk to your doctor as they may want to switch you to a different medicine.

Make sure you rest and drink plenty of fluids. Do not drink too much alcohol.

Ask your pharmacist to recommend a painkiller. Talk to your doctor if your headaches do not go away or are severe.

If you find you're putting on weight after taking valproic acid, try to have a healthy balanced diet. Regular exercise will also help you keep your weight stable.

Your doctor will usually monitor your weight while you're taking this medicine. Speak to them if you have any concerns.

If these symptoms bother you, ask your doctor whether it's possible to lower your dose. Your hair may regrow after either reducing your dose or switching to a different medicine.

As well as being a side effect of valproic acid, a late period is a sign that you could be pregnant, and valproic acid can be harmful for an unborn baby.

If you usually have regular periods, take a pregnancy test if your period is late, and speak to your doctor straight away if the result is positive.

Changes to your periods can also be a symptom of polyendocrine metabolic ovarian syndrome (PMOS), a rare side effect of valproic acid. Your doctor will be able to do some tests to check whether you have PMOS.

Keep taking the medicine, but talk to your doctor or a pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.