Common questions about valproic acid - Brand names: Belvo, Depakote, Convulex, Syonell

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

It's not fully understood 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 clear how valproic acid prevents migraine. It may limit how your nerves transmit pain signals in the brain.

For treating epilepsy, valproic acid prevents epileptic seizures by reducing too much electrical activity in your brain.

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

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

However, there are possible 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 healthy diet can also help to keep your bones strong.

Valproic acid is not known to be addictive.

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.

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 stop taking valproic acid safely.

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.

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 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 valproic acid if you have a health problem that means you cannot take other migraine medicines.

There are many different medicines for treating epilepsy. It's not possible to say that one works better than the others. 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 sex, the medicines you're already taking and any other health problems you have.

Usually, epilepsy is treated using a single medicine. If this medicine is not working well, or you're getting side effects, your doctor will try you on a different one.

If a single medicine does not prevent 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's not 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

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 GPs surgery. You'll need to fill in the form, then your doctor will sign it and send it off.

Valproic acid does not affect any type of contraception, including the combined pill and emergency contraception.

However, if valproic acid makes you vomit or have severe, watery diarrhoea, or any diarrhoea that lasts for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.

Find out more:

• What to do if you're sick or have diarrhoea when taking the combined pill
• What to do if you're sick or have diarrhoea when taking the progestogen-only pill

If there's a chance you could become pregnant while taking valproic acid you must use contraception. Your doctor will put you on Prevent, the valproatepregnancy prevention programme.

Find out more about Prevent on the Electronic Medicines Compendium website (PDF only, 318KB).

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

You may feel sleepy, tired or dizzy when you first start taking valproic acid. This may also happen if your dose has increased. If this happens to you, do not drive, cycle or use machinery or tools 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.

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

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.

Talk to your doctor if you think you might use recreational drugs while taking valproic acid.

You can find out more about the side effects of recreational drugs on the Frank website.