Sodium valproate: uses, Prevent programme and safety

Sodium valproate is an older anti-seizure medicine that is also prescribed for bipolar disorder and for preventing migraine. The NHS names Dyzantil, Epilim, Episenta and Epival as UK brands. It is available only on prescription.

The NHS separates its guidance into who can take it, how to take it, side effects, pregnancy and breastfeeding, interactions and common questions, and it supplies separate guides for women and for men. Those guides are the formal safety documents, and this page only summarises the points in the pages that were checked.

The central safety rule is stated plainly by the NHS: girls and women who need to take sodium valproate must be enrolled on Prevent, the valproate pregnancy prevention programme. Enrolment is something to arrange with the prescriber, who can explain what is involved, including what is required for contraception and for regular reviews.

The programme exists because of the risks to babies exposed during pregnancy. It is not a reason for anyone to stop treatment on their own, since a seizure can be dangerous; it is a reason to have the pregnancy conversation early and to keep reviews up to date.

The NHS says sodium valproate may affect male fertility. It also describes a potential risk of developmental or behavioural problems in a baby if a partner becomes pregnant while the man is taking it.

For that reason doctors typically suggest alternative treatments for men who could father a child or who are planning to, and men already taking it should ask for a review rather than change anything by themselves.

Most adults can take sodium valproate for epilepsy, bipolar disorder or migraine prevention, and most children for epilepsy. The NHS lists the following as reasons it may be unsafe.

• A previous allergic reaction to the drug or to similar medicines.

• Liver problems.

• Rare metabolic or genetic conditions: porphyria, a urea cycle disorder, a mitochondrial disorder or primary carnitine deficiency.

Slow-release tablets are swallowed whole with water or squash and not chewed. Crushable tablets can be mixed with soft food or a drink, and the liquid is measured with the supplied syringe or spoon. Treatment generally starts on a low dose that the doctor increases over a few days or weeks.

The NHS page gives usual daily ranges for adults and for children aged 12 and over: 600 to 2,000mg for epilepsy, 750 to 2,000mg for bipolar disorder and 400 to 1,500mg for migraine prevention, split into two doses. Younger children have doses based on weight. Your own dose will be set by your prescriber.

For once-daily dosing, a forgotten dose is taken unless it is within a few hours of the next one. For twice-daily dosing, skip it if it is nearly time for the next dose. Never double up.

More than one in 100 people get stomach pain or sickness, diarrhoea, a dry or sore mouth or swollen gums, tiredness, headaches, weight gain, thinning hair or changes in hair colour or texture, and changes to periods. The NHS advises that a delayed period can be a sign of pregnancy and should be checked with a doctor.

Serious effects are described in two tiers. The NHS says to call 111 or see a doctor straight away for yellowing of the eyes or skin with dark urine (possible liver problems), severe nausea, vomiting or stomach pain (possible pancreatitis), unusual bruising or bleeding, and tremors or abnormal eye movements. Call 999 for suicidal thoughts or serious allergic reactions. Long-term use may cause thinning of the bones, and a doctor can arrange bone strength testing. Suspected side effects can be reported through Yellow Card.

Do not stop suddenly without medical guidance. People with epilepsy are told to keep a steady routine, as missing doses can trigger a seizure. An overdose can cause sickness, headache, dizziness, muscle weakness, breathing problems, confusion and fainting, and the NHS advises 111 if you feel unwell after taking too much.

Alternatives vary with the condition, and a specialist chooses them. The guide to epilepsy medication choices on this site shows how that decision is approached, and the epilepsy and pregnancy guide covers why valproate is often reviewed.