Question to the Department of Health and Social Care:

To ask the Secretary of State for Health and Social Care, whether the Medicines and Healthcare Products Regulatory Agency is taking steps to investigate the potential effect of valproate on men and their fertility.

Valproate is a medicine authorised for the treatment of epilepsy and bipolar disorder. The product information for all medicines is approved by the Medicines and Healthcare products Regulatory Agency (MHRA). The product information for valproate containing medicines has listed male infertility as a possible side effect since 2011.

In 2021, the MHRA reviewed the totality of data on the risk of male infertility associated with valproate including evidence for reversibility of effects. Although the data are limited, the valproate product information was updated in 2021 to advise that male infertility is usually reversible after treatment discontinuation and may be reversible after dose reduction. However, in some cases, the reversibility of male infertility was unknown.

The underlying biological mechanism is currently uncertain, but animal data on valproate show toxicity to testicular tissue structure and function. MHRA keeps all data under review and is investigating the clinical relevance of these data with the marketing authorisation holders.