How it works
What does valproate do?
Valproate helps to treat the symptoms of mania (being very excited, overactive, easily irritated or distracted) in people with bipolar disorder. It is also used to prevent these symptoms from coming back.
With bipolar disorder, a person's mood changes from very high (mania) to very low (depression). Valproate is less effective at preventing the symptoms of depression in bipolar disorder from returning, but there are other medicines that can help with this.
Valproate is a type of medicine called a mood stabiliser as it reduces feelings of excitability and over-activity and reduces mood swings.
Medicines like valproate can keep your mood stable (stop it going too high or too low).
We do not fully understand how valproate works for mania and bipolar disorder, but we have some ideas about it.
Valproate blocks the breakdown of a chemical in the brain called gamma-aminobutyric acid (GABA). GABA is a chemical that calms nerve excitability in the brain. If valproate blocks its breakdown, there is more GABA to create this calming effect.
There are gateways in the brain called ‘sodium channels’, which can be open or closed. When they are open, chemicals go through that can make us excited.
Valproate may also work by locking on to closed sodium channels and keeping them closed. Sodium cannot pass through, which reduces nerve excitement.
How long does valproate take to start working?
If you are having a manic episode the doctor is likely to increase your dose quite quickly over a few days.
It usually only takes a few days for valproate to start working and to have its best effect.
Your dose is likely to be reduced in the longer term to get the best effect for you. This is because you are unlikely to need the same high dose as you would in a manic episode to provide longer-term benefit.
How long will I need to take valproate?
You will need to take valproate for several months after you feel better, otherwise your symptoms can come back.
Your doctor will advise you how long you'll need to stay on valproate, as it depends on what you are taking it for. If you are taking it to prevent the symptoms of mania from coming back, it might be about six months.
If you stop taking the valproate too soon, there is more chance that your symptoms will come back.
Your doctor needs to know if...
You need to talk to your doctor or pharmacist before starting treatment with valproate if any of the following apply to you:
- you currently have liver problems
- you or someone in your family has ever had serious liver problems related to medicines
- you have systemic lupus erythematosus (an inflammatory condition also called lupus or SLE)
- you have a rare illness called porphyria which affects your metabolism
- you are trying to get pregnant
You should only take valproate as agreed with your doctor
You will get the most benefit from your valproate if you take it every day.
Make sure that you know your dose. If it is not written on the label, check with your pharmacist or doctor.
Valproate semisodium is normally taken twice a day but sometimes it may be three times a day.
The starting dose is normally 750mg per day but will probably be increased to between 1000mg and 2000mg a day.
Sodium valproate is available as ‘controlled-release’ (also called ‘prolonged-release’) tablets, capsules and granules that mean you only need to take it once a day.
The controlled-release capsules or tablets should be swallowed whole with a glass of water and not crushed or chewed.
The controlled-release granules can either be sprinkled on a small amount of soft cold food, taken in a drink, or poured directly into the mouth and washed down with a cold drink. If the granules are added to a drink, after you’ve had the drink the glass should be rinsed with a small amount of water and you should drink this water as well, as some granules may stick to the glass. The granules should not be crushed or chewed.
Controlled-release medicines might help you if you find it difficult to remember all the doses and would otherwise need to take doses at school, university or work.
Valproate can be taken with or after a meal. Taking it with food can help to reduce the chance of feeling sick. Not everyone feels sick with valproate, but this is one of the possible side effects.
Some of the valproate preparations have a special coating (“enteric” or “gastro-resistant” coating) to protect the tablet from stomach acid. This tablet should be swallowed whole with a glass of water - do not chew it as it tastes bitter and you will break the protective coat.
What if I miss a dose?
If you remember later during the day, take it as soon as you remember - unless you are less than four hours away from your next dose. If you forget to take it by then, just start again with the next dose.
Do not take a double dose.
What will happen if I forget to take my valproate?
If you forget to take it for a few days, you may start getting your symptoms back and should talk to your doctor about it.
Stopping the use of valproate
Once you start taking valproate, the brain adjusts to having its calming effect. If you stop taking the valproate all at once, the chemical balance in your brain starts to change again, meaning you could get your old symptoms back.
However, you can stop taking valproate safely with your doctor’s help.
Go and speak to your doctor if you have missed a few doses or have decided to stop taking your medication.
When you agree with your doctor to stop the medicine, you will carry on with a dose that gradually decreases over about a month.