Valproic acid

1. About valproic acid

Valproic acid is used to treat bipolar disorder.

It's occasionally used to prevent migraine headaches and can also be used to treat epilepsy.

This medicine is only available on prescription. It comes as capsules or tablets.

2. Key facts

  • It's usual to take valproic acid 2 or 3 times a day. You can take it with or without food.
  • If you're pregnant, or there's a chance you could become pregnant, valproic acid is not recommended for bipolar disorder or migraine. For epilepsy, your doctor will only prescribe valproic acid for you if there are no other suitable treatments.
  • You'll usually start on a low dose. Your dose will gradually increase over a few days or weeks.
  • Sodium valproate and semisodium valproate are similar to valproic acid and work in the same way. However, these medicines are used to treat different illnesses and doses will vary.
  • The most common brand names of valproic acid are Depakote and Convulex. Epilim Chrono and Epilim Chronosphere contain mostly sodium valproate, with some valproic acid.

3. Who can and can't take valproic acid

Valproic acid can be taken by adults and children to treat bipolar disorder or epilepsy.

It can be taken by adults (aged 18 and above) to prevent migraine.

Valproic acid isn't suitable for some people:

  • women who could become pregnant - unless they're on Prevent, the valproate pregnancy prevention programme
  • younger women or girls who are having sex (even if their periods haven't started) - unless they're on Prevent, the valproate pregnancy prevention programme

If you're pregnant, do not take valproic acid to treat bipolar disorder or to prevent migraines. This is because valproic acid can seriously harm an unborn child.

For treating epilepsy during pregnancy, your doctor will only prescribe valproic acid for you if no other treatments work.

To make sure valproic acid is safe for you, tell your doctor if you:

  • have ever had an allergic reaction to valproic acid or other medicines in the past
  • have liver problems
  • have a rare metabolic or genetic illness such as porphyria, urea cycle disorder or mitochondrial disorder
  • are pregnant or trying to get pregnant

4. How and when to take it

Valproic acid is a prescription medicine. It's important to take it as advised by your doctor.

  • For treating bipolar disorder in adults: the usual dose is 750mg to 2,000mg a day, split into 2 or 3 doses.
  • For treating bipolar disorder in children: the doctor will work out the right dose for your child.
  • For preventing migraine in adults: daily doses vary from a single dose of 400mg to 1,500mg split into 2 doses.
  • For treating epilepsy in adults and older children (aged 12 years and over): the usual dose is 600mg to 2,000mg a day, split into 2 to 4 doses.
  • For treating epilepsy in younger children (weighing more than 20kg): doses vary. The doctor will use your child's weight to work out the right amount of medicine to give them.

If you need to take your medicine a few times a day, the amount you take each time depends on your total daily dose. You'll take a number of equal doses that add up to your daily total. Ask your doctor or a pharmacist if you're unsure how much to take each time.

If you're taking valproic acid and also have kidney problems, your doctor may prescribe a lower dose.

How and when take it

Valproic acid comes as "gastro resistant" tablets and capsules. These release the valproic acid into your body as soon as they pass through your stomach.

Swallow the tablets or capsules whole with a drink of water or juice. Do not chew them.

You can take valproic acid with or without food, but it’s best to do the same each time.

  • Gastro resistant tablets - you'll usually take these 2 to 3 times a day.
  • Gastro resistant capsules - you'll usually take these 2 to 4 times a day.

If you're taking valproic acid twice a day, try to leave a gap of 10 to 12 hours between doses. For example you could take your first dose in the morning (between 7am and 8am) and a second dose in the evening (between 7pm and 8pm).

If you take your medicine 3 to 4 times a day, try to space your doses evenly through the day. If you need to take 3 doses, for example, you could take your medicine first thing in the morning, early afternoon and bedtime.

Will my dose go up or down?

To prevent the chance of side effects, your doctor will start you off on a low dose of valproic acid. They will increase it gradually over a few days or weeks.

Once you find a dose that suits you, it will usually stay the same - unless your condition changes, or your doctor starts you on a new medicine that may interfere with valproic acid.

What if I forget to take it?

If you forget a dose take it as soon as you remember, unless it's less than 2 hours to your next dose. In this case, skip the missed dose and take your next one at the usual time.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

If you have epilepsy, it’s important to take this medicine regularly. Missing doses can trigger a seizure.

If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

Taking too much valproic acid by accident can lead to symptoms such as:

  • feeling or being sick (nausea or vomiting)
  • headaches, or feeling dizzy
  • muscle weakness
  • breathing problems
  • feeling confused, or changes to your normal behaviour
  • passing out

Call your doctor or go to A&E straight away if you take too much valproic acid and feel unwell

If you need to go to hospital, take the valproic acid packet or the leaflet inside it, plus any remaining medicine, with you.

Find your nearest hospital accident and emergency (A&E) department.

5. Side effects

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

Common side effects

These common side effects may happen in more than 1 in 100 people. They're usually mild and go away by themselves.

Keep taking the medicine but talk to your doctor if these side effects bother you or don't go away:

  • stomach pain, feeling or being sick (nausea or vomiting)
  • diarrhoea
  • dry or sore mouth, or swollen gums
  • shakes (tremors) in a part of your body, or unusual eye movements
  • feeling tired or sleepy
  • headache
  • weight gain
  • thinning hair, or changes to the colour or texture of your hair
  • irregular or delayed periods

Serious side effects

It's unusual to have serious side effects after taking valproic acid. Tell a doctor straight away if you have:

  • thoughts of harming or killing yourself - a small number of people taking valproic acid have had suicidal thoughts
  • yellowing of your skin or whites of your eyes - these may be warning signs of liver problems
  • long-lasting and severe nausea, vomiting or stomach pain - these may be warning signs of an inflamed pancreas
  • unusual bruises or bleeding - these may be warning signs of a blood disorder

Serious allergic reaction

In rare cases, valproic acid may cause a serious allergic reaction (anaphylaxis).

Contact a doctor straight away if:

  • you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
  • you're wheezing
  • you get tightness in the chest or throat
  • you have trouble breathing or talking
  • your mouth, face, lips, tongue or throat start swelling

These are warning signs of a serious allergic reaction. A serious allergic reaction is an emergency.

These are not all the side effects of valproic acid. For a full list, see the leaflet inside your medicine packet.

Information:

You can report any suspected side effect to the UK safety scheme.

6. How to cope with side effects

What to do about:

  • Stomach pain, feeling or being sick (nausea or vomiting) - take valproic acid with or after a meal or snack. It may also help if you don't eat rich or spicy food.
  • Diarrhoea - have small but frequent sips of water. 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.
  • Dry or sore mouth, or swollen gums - for a dry mouth try sugar-free gum or sweets, or sipping cold drinks. If this doesn't help, or you have mouth ulcers, talk to your pharmacist or doctor. If you're bothered by swollen gums or this symptom doesn't go away, talk to your doctor or dentist.
  • Shakes (tremors) in a part of your body, or unusual eye movements - talk to your doctor if this is bothering you. These symptoms can be a sign that the dose is too high for you. It may help to change your dose or take your medicine at a different time of day.
  • Feeling tired or sleepy - as your body gets used to valproic acid, these side effects should wear off. If these symptoms don't get better within a week or two, your doctor may either reduce your dose or increase it more slowly. If that doesn't work you may need to switch to a different medicine.
  • Headache - 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 last longer than a week or are severe.
  • Weight gain - 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.
  • Thinning hair, or changes to the colour or texture of your hair - 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.
  • Irregular or delayed periods - if you usually have regular periods, tell your doctor straight away if your period is late. As well as being a side effect of valproic acid, it's a sign that you could be pregnant - and valproic acid can be harmful for an unborn baby. Changes to your periods can also be a symptom of polycystic ovary syndrome (PCOS), a rare side effect of valproic acid. Your doctor will be able to do some tests to check whether you have PCOS.

7. Pregnancy and breastfeeding

Valproic acid is generally not recommended in pregnancy, as it can harm your unborn baby. If there's a chance you could become pregnant while taking this medicine, your doctor will put you on Prevent, the valproate pregnancy prevention programme.

If you think you might already be pregnant, contact your doctor or nurse as soon as possible.

If you're taking valproic acid for epilepsy and you become pregnant, do not stop taking your medicine without talking to your doctor first. This is because your symptoms or seizures may get worse.

Your doctor may continue to prescribe valproic acid, but only if there's no other suitable treatment for your epilepsy.

For more information about how valproic acid can affect you and your baby during pregnancy, read this leaflet on the Best Use of Medicines in Pregnancy (BUMPS) website.

Valproic acid and breastfeeding

Small amounts of valproic acid pass into your breast milk. As the amount is so small it's unlikely to harm your baby, unless your baby was born premature or has kidney problems.

Talk to your doctor about the benefits and risks of taking valproic acid while breastfeeding. They may still recommend valproic acid if it's the only medicine that works for you.

Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

8. Cautions with other medicines

There are some medicines that may interfere with how valproic acid works. Valproic acid can also affect the way other medicines work.

Tell your doctor if you're taking (or before you start taking):

  • any other medicines for epilepsy such as carbamazepine
  • medicines for thinning the blood such as warfarin
  • aspirin for pain relief or low-dose aspirin
  • cimetidine, a medicine for stomach ulcers
  • medicines to treat HIV and AIDS such as ritonavir
  • antibiotics such as erythromycin
  • medicines for depression or other mental health problems such as venlafaxine, quetiapine or diazepam
  • cholesterol-lowering medicines such as cholestyramine
  • medicines to prevent malaria such as mefloquine or chloroquine

Mixing valproic acid with herbal remedies or supplements

It's not possible to say whether complementary medicines and herbal supplements are safe to take with valproic acid.

They're not tested in the same way as pharmacy and prescription medicines. They're generally not tested for the effect they have on other medicines.

Important

For safety, tell your doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.

9. Common questions

How does valproic acid work?

Valproic acid is an anticonvulsant (or anti-epileptic) medicine.

We don't fully understand how this medicine works for treating bipolar disorder. However valproic acid is thought to reduce or prevent manic episodes by increasing the amount of a chemical called gamma-aminobutyric acid (GABA) in the brain. GABA blocks transmission across nerves in the brain and has a calming effect.

It's not really clear how valproic acid or sodium valproate prevent migraine. These medicines may limit how your nerves transmit pain signals in the brain.

For treating epilepsy, valproic acid prevents epileptic fits by reducing excessive electrical activity in your brain.

When will I feel better?

It takes a few weeks for valproic acid to work properly. You may still have symptoms during this time.

How long will I take it for?

Once your illness is under control, you'll usually need to keep taking valproic acid for many years.

Can I get addicted to valproic acid?

Valproic acid is not known to be addictive.

Is it safe to take it for a long time?

Many people can take valproic acid safely for many months or years.

However there are potential side effects that can happen over a long time. Long-term treatment with valproic acid can cause osteoporosis and osteopenia (increasing your risk of breaking a bone).

Your doctor can arrange for tests to check the strength of your bones. Regular exercise and a good diet can also help to keep your bones strong.

Can I get epilepsy medicines for free?

If you have epilepsy, you're entitled to free prescriptions for all of your medicines (not just your epilepsy ones).

To claim your free prescriptions you'll need a medical exemption certificate.

The application form for the medical exemption certificate is called FP92A. You can get this from your doctor's surgery. You will need to fill in the form, then your doctor will sign it and send it off.

Are there similar medicines to valproic acid?

Sodium valproate and semisodium valproate are very similar to valproic acid. They work in the same way but these medicines are sometimes given at different doses for different conditions.

If you decide to try sodium valproate or semisodium valproate instead, your doctor will explain how to come off valproic acid safely.

How does valproic acid compare with other medicines for treating bipolar disorder?

If you have bipolar disorder, there are several types of medicine to prevent mood swings and treat mania. It's not possible to say that one works better than another and it varies from person to person.

Lithium is commonly used for bipolar disorder, as well as anti-epileptic medicines like valproic acid and antipsychotic medicines like olanzapine. You can take valproic acid instead of lithium, or together with lithium, depending on what your doctor recommends.

Your doctor or specialist will find the medicines that work best for you. It depends on your mood swings, how often they happen, how severe they are and how well you cope with a medicine.

How does it compare with other medicines for migraine?

For many people topiramate, propranolol and amitriptyline work better than valproic acid at preventing migraines. These medicines are likely to cause fewer side effects - so your doctor or specialist will usually prescribe one of these first.

Valproic acid isn't used as often for preventing migraine. However your doctor may recommend it if these other medicines are causing side effects or aren't working for you.

Your doctor may also prescribe valproic acid if you have a health problem that means you can't take other migraine medicines.

How does it compare with other medicines for epilepsy?

There are many different medicines for treating epilepsy (anti-epileptic medicines). It's not possible to say that one works better than the other. It varies from person to person and depends on the type of seizures and how often you have them.

Before prescribing a medicine, your doctor will also take into account your age and gender, the medicines you're already taking and any other health problems you may have.

It's usual to try to treat epilepsy using a single medicine. If this medicine isn't working well, or you're getting side effects, your doctor will generally try you on a different one.

If a single medicine isn't preventing your seizures, then your doctor may recommend taking 2 or more anti-epileptic medicines at the same time.

If valproic acid is giving you side effects, or you're worried it isn't suitable for you, ask your doctor or specialist to recommend a different medicine.

Other anti-epileptic medicines include:

  • Carbamazepine
  • Clobazam 
  • Ethosuximide
  • Gabapentin
  • Lamotrigine
  • Levetiracetam
  • Phenytoin
  • Pregabalin
  • Topiramate
What will happen when I come off it?

Do not stop taking valproic acid suddenly, unless your doctor tells you to.

You're unlikely to get any extra symptoms when you stop taking this medicine. However if you're taking it for bipolar disorder or to prevent migraine, your condition could get worse for a short time after you stop taking the medicine.

If you're taking valproic acid for epilepsy, it's possible that you'll get seizures again once you stop taking it. You can prevent these withdrawal seizures by reducing your dose of valproic acid gradually.

Will recreational drugs affect it?

Valproic acid can affect recreational drugs like cannabis and heroin.

If you use recreational drugs alongside valproic acid, you may be more likely to have side effects like panic attacks, anxiety and memory loss.

Can I drink alcohol with it?

Drinking alcohol while taking valproic acid may make you feel sleepy or tired. For this reason it's best to stop drinking alcohol during the first few days, until you see how the medicine affects you.

If you do drink, try not to have more than the recommended guidelines of up to 14 units of alcohol a week. A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units of alcohol.

Will it affect my fertility?

Valproic acid can reduce fertility in both men and women. Once you stop taking this medicine, your fertility will return.

In men valproic acid has been reported to cause infertility. However, this is rare.

In women it can change your menstrual cycle, causing delayed or missed periods. Valproic acid has also been reported to cause polycystic ovary syndrome (PCOS), though this happens rarely.

Talk to your doctor if you're concerned about how valproic acid may affect your fertility.

Valproic acid is no longer recommended for girls or women who may become pregnant. If you're taking valproic acid and want to start a family, it's important to talk your doctor as soon as possible. This is because valproic acid can harm your unborn child.

Will it affect my contraception?

Valproic acid doesn't affect any type of contraception, including the combined pill and emergency contraception.

Women and girls who could become pregnant while taking sodium valproate must use contraception. Your doctor will put you on Prevent, the valproate pregnancy prevention programme.

Speak to a pharmacist or your doctor if you have any questions about this programme.

Can I drive or ride a bike?

You may feel sleepy, tired or dizzy when you first start taking valproic acid. This may also happen if your dose has increased. If you're affected, do not drive or ride a bike until you feel more alert.

If you have epilepsy, you're not allowed to drive until you've had no seizures for 1 year (or only have seizures while you're asleep).

If you change your epilepsy medicine, you are not allowed to drive for the first 6 months of treatment.

Can valproic acid be used to treat dementia?

You may have read some stories in the news linking valproic acid to treatment for dementia.

It was hoped that valproic acid could prevent aggressive behaviour and agitation in people with different types of dementia, including Alzheimer's disease.

However, the medicine has been tested in a number of trials and overall the results show it's unlikely to improve these symptoms.

Related conditions

Page last reviewed: 24/09/2018
Next review due: 24/09/2021