Sodium Valproate (Psychiatric use)

How it works

Its mood-stabilising action is incompletely understood but involves enhancement of GABAergic transmission and modulation of voltage-gated sodium channels, reducing neuronal excitability.

Prescribing in practice

• It is highly teratogenic and must not be used in women or girls of childbearing potential unless the conditions of the MHRA Pregnancy Prevention Programme are met, as it causes major malformations and neurodevelopmental harm.
• It can cause rare but serious hepatotoxicity and pancreatitis, so check liver function before and during early treatment and warn about abdominal pain, vomiting or jaundice.
• It interacts widely and inhibits the metabolism of other drugs such as lamotrigine, increasing the risk of serious rash.

Monitoring

Check liver function and full blood count before and periodically during treatment, monitor mood and weight, and review pregnancy-prevention requirements at least annually in those of childbearing potential.

Counselling the patient

• It must not be taken in pregnancy or by anyone who could become pregnant without highly effective contraception and specialist review.
• Report unexplained bruising or bleeding, severe abdominal pain, vomiting, or yellowing of skin or eyes promptly.
• Do not stop suddenly and discuss any plans for pregnancy with your specialist well in advance.

Evidence & guidelines

NICE positions valproate as a second-line bipolar mood stabiliser, and MHRA regulatory measures mandate the Pregnancy Prevention Programme and tightened restrictions in those able to have children.