Valproic acid is a prescription medicine. It's important to take it as your doctor tells you.
Dosage and how to take valproic acid
Dosage
The usual dose of valproic acid for treating bipolar disorder in adults is 750mg to 2,000mg a day, split into 2 or 3 doses.
The usual dose for preventing migraine in adults is 500mg to 1,000mg a day, split into 2 or 3 doses.
The usual dose for treating epilepsy in adults and children aged 12 years and over is 600mg to 2,000mg a day, split into 2 to 4 doses. Some people take a higher dose of 2,500mg a day.
For younger children who weigh more than 20kg, the doctor will use your child’s weight to work out the right dose.
If you need to take your medicine more than once a day, you'll take 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 have kidney problems, your doctor may prescribe a lower dose.
Changes to your dose
To reduce 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 affect valproic acid.
How to 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 squash. Do not chew them.
You can take valproic acid with or without food, but it's best to do the same each time.
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 your second dose in the evening (between 7pm and 8pm).
If you take it 3 to 4 times a day, try to space your doses evenly throughout the day. If you need to take 3 doses, for example, you could take a dose first thing in the morning, early afternoon and bedtime.
How long to take it for
Once your condition is under control, you'll usually need to keep taking valproic acid for many years.
Do not stop taking it suddenly, unless your doctor tells you to.
If you forget to take it
If you forget a dose of valproic acid, take it as soon as you remember, unless it's nearly time for your next dose. In this case, skip the missed dose and take your next dose 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 often forget doses, 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.
If you take too much
Taking too much valproic acid can cause symptoms such as:
- feeling or being sick (nausea or vomiting)
- headaches
- feeling dizzy
- muscle weakness
- breathing problems
- feeling confused, or changes to your normal behaviour
- fainting
Urgent advice: Contact 111 for advice now if:
- you take more than your prescribed dose of valproic acid and feel unwell
Call 111 or get help from 111 online.
If you need to go to A&E, do not drive yourself. Get someone else to drive you or call for an ambulance.
Take the valproic acid packet or the leaflet inside it, plus any remaining medicine, and any other medicines you take with you.