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Sodium valproate - Brand names: Epilim, Episenta, Epival

On this page

  1. About sodium valproate
  2. Key facts
  3. Who can and cannot take sodium valproate
  4. How and when to take it
  5. Side effects
  6. How to cope with side effects
  7. Pregnancy and breastfeeding
  8. Cautions with other medicines
  9. Common questions

1. About sodium valproate

Sodium valproate is used to treat epilepsy and bipolar disorder.

It's occasionally used to prevent migraine headaches.

This medicine is only available on prescription. It comes as capsules, tablets and a liquid that you swallow. It also comes as granules that you mix with food or drink.

Sodium valproate can also be given by injection, but this is usually only done in hospital.

It's not recommended for girls or women who may become pregnant. Your doctor will put you on Prevent, the valproate pregnancy prevention programme.

NHS coronavirus advice

While everyone is staying at home as much as possible, it can be hard to know what to do if you need medical help.

If you are taking sodium valproate, get advice now if you think you are pregnant or might become pregnant. The valproate pregnancy prevention programme is important and is still running.

Your doctor or nurse will talk to you on a video call or phone call. They can also arrange safe visits to see you, if you need them to.

If you usually have an annual review with your specialist, this can also be done as a video or phone call. Do not delay this important appointment.

Updated: 26 May 2020

2. Key facts

  • It's usual to take sodium valproate once or twice a day. You can take it with or without food.
  • If you're pregnant, or there's a chance you could become pregnant, your doctor will only prescribe sodium valproate 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.
  • Valproic acid and semisodium valproate are similar to sodium valproate and work in the same way. However these medicines are used to treat different illnesses and doses will vary.

3. Who can and cannot take sodium valproate

Sodium valproate can be taken by adults and children to treat epilepsy or bipolar disorder.

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

Sodium valproate is not 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 have not started) – unless they're on Prevent, the valproate pregnancy prevention programme

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

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

To make sure sodium valproate is safe for you, tell your doctor if you:

  • have ever had an allergic reaction to sodium valproate 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

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


The usual dose for treating:

  • epilepsy in adults and older children (aged 12 years and over): 600mg to 2,000mg a day, taken as either 1 or 2 doses. Some people may take a higher dose of 2,500mg a day.
  • epilepsy in younger children (aged 1 month to 11 years) – doses vary. The doctor will use your child's weight to work out the right amount of medicine to give them.
  • bipolar disorder in adults 750mg to 2,000mg a day, taken either as a 1 or 2 doses.
  • bipolar disorder in children – the doctor will work out the right dose for your child.
  • migraine in adults – daily doses vary from a single dose of 400mg to 1,500mg split into 2 doses.

If your doctor tells you to take sodium valproate twice a day, you'll usually take half in the morning and half in the evening (to make up your full daily dose).

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

How and when take it

With "prolonged release" (or "sustained release") sodium valproate, the medicine is released gradually into your body.

With "gastro resistant" tablets, the medicine is released as soon as it passes through your stomach. This means the sodium valproate gets into your body more quickly.

You can take sodium valproate with or without food, but it's best to do the same each time.

Prolonged release tablets and capsules – swallow these whole with a drink of water or juice. Do not chew them. You'll usually take these once a day – unless you're on a high dose and your doctor tells you to take your medicine twice a day.

Prolonged release granules – add the granules to a small drink, then stir and swallow. If your prefer, sprinkle the granules onto any soft food that you can swallow whole. Do not chew the granules. Your doctor will tell you to take these either once or twice a day.

Gastro resistant tablets – swallow these whole with a drink of water or juice. Do not chew them. You'll usually take these twice a day.

Crushable tablets – crush these using the back of a spoon and mix the powder with some soft food that you can swallow whole. If you prefer, add the powder to a small drink, then stir and swallow. You'll usually take this medicine twice a day.

Liquid – use the plastic syringe or spoon that comes with your medicine to measure the correct dose. If you do not have one, ask your pharmacist. Do not use a kitchen teaspoon as you will not get the right amount. You'll usually take the liquid twice a day.

If you're taking sodium valproate once a day, you can choose a time that suits you. Just try to keep to the same time every day.

If you're taking sodium valproate 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).

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 sodium valproate. 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 sodium valproate.

What if I forget to take it?

If you've missed a dose, what you do next depends on whether you usually take your medicine once or twice a day.

If you take sodium valproate:

  • once a day – take the forgotten dose as soon as you remember unless it's within a few hours of the next dose. In this case, skip the missed dose and take your next dose as normal.
  • twice a day – take the forgotten dose as soon as you remember unless it's within 2 hours of the next dose,. In this case, skip the missed dose and take your next dose as normal.

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 sodium valproate 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

Urgent advice: Call your doctor or go to A&E straight away if:

  • you take too much sodium valproate and feel unwell

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

Find your nearest A&E.

5. Side effects

Like all medicines, sodium valproate 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 do not 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 sodium valproate. Tell a doctor straight away if you have:

  • thoughts of harming or killing yourself – a small number of people taking sodium valproate 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, sodium valproate may cause a serious allergic reaction (anaphylaxis).

Immediate action required: Call 999 or go to A&E now 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

You could be having a serious allergic reaction and may need immediate treatment in hospital.

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


You can report any suspected side effect using the Yellow Card safety scheme.

Visit Yellow Card for further information.

6. How to cope with side effects

What to do about:

  • stomach pain, feeling or being sick (nausea or vomiting) – take sodium valproate with or after a meal or snack. It may also help if you do not 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 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.
  • 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 sodium valproate, these side effects should wear off. If these symptoms do not get better within a week or two, your doctor may either reduce your dose or increase it more slowly. If that does not work you may need to switch to a different medicine.
  • headaches – 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 sodium valproate, 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 sodium valproate, 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

Sodium valproate 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 sodium valproate 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 sodium valproate, but only if there's no other suitable treatment for your epilepsy.

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

Sodium valproate and breastfeeding

Small amounts of sodium valproate 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 sodium valproate while breastfeeding. They may still recommend sodium valproate if it's the only medicine that works for you.

Non-urgent advice: 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 sodium valproate works. Sodium valproate 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 sodium valproate with herbal remedies or supplements

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

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: Medicine safety

Tell your doctor or pharmacist if you're taking any other medicines, including herbal medicines, vitamins or supplements.

9. Common questions

How does sodium valproate work?

Sodium valproate is an anticonvulsant (or anti-epileptic) medicine. It prevents epileptic fits by reducing excessive electrical activity in your brain.

We do not fully understand how this medicine works for treating bipolar disorder. However, sodium valproate 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 sodium valproate prevents migraine. It may limit how your nerves transmit pain signals in the brain.

When will I feel better?

It takes a few weeks for sodium valproate 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 sodium valproate for many years.

Can I get addicted to sodium valproate?

Sodium valproate is not known to be addictive.

Is it safe to take it for a long time?

Many people can take sodium valproate safely for many months or years.

However, there are potential side effects that can happen over a long time. Long-term treatment with sodium valproate 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 sodium valproate?

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

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

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 is not working well, or you're getting side effects, your doctor will generally try you on a different one.

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

Sodium valproate works for quite a few different types of epilepsy. If it's giving you side effects, or you're worried it is not suitable for you, ask your doctor or specialist to recommend a different medicine.

Other anti-epileptic medicines include:

How does it compare with other medicines for migraine?

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

Sodium valproate is not used as often for preventing migraine. However, your doctor may recommend it if these other medicines are causing side effects or are not working for you.

Your doctor may also prescribe sodium valproate if you have a health problem that means you cannot take other migraine medicines.

How does sodium valproate 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 sodium valproate and antipsychotic medicines like olanzapine. You can take sodium valproate 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.

Should I stick to the same type of sodium valproate?

Once you're on a dose of sodium valproate that suits you, you're likely to keep taking the same type or brand. This is because it can be a problem to swap from "modified release" to "gastro resistant" tablets.

Some people may change brands to try a different type of sodium valproate - for example they may want to try the granules instead of the tablets. If you need to change brand your doctor or pharmacist will explain how to do so safely.

However, if your epilepsy has been difficult to control in the past and the brand you're taking is working well for you, your doctor may recommend staying on the same one.

What will happen when I come off it?

Do not stop taking sodium valproate 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 sodium valproate 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 sodium valproate gradually.

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.

Will recreational drugs affect it?

Sodium valproate can affect recreational drugs like cannabis and heroin.

If you use recreational drugs alongside sodium valproate, 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 sodium valproate 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?

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

In men sodium valproate has been reported to cause infertility. However, this is rare.

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

Talk to your doctor if you're concerned about how sodium valproate may affect your fertility.

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

Will it affect my contraception?

Sodium valproate does not 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 sodium valproate. 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, your doctor will tell you whether you need to stop driving and for how long.

Can sodium valproate be used to treat dementia?

You may have read some stories in the news linking sodium valproate to treatment for dementia.

It was hoped that sodium valproate 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.