MEN taking epilepsy drug valproate have been urged to use contraception by UK health officials due to the risk of birth defects.
The Medicines and Healthcare products Regulatory Agency said babies born to dads taking the medicine are more likely to have autism, learning difficulties or other developmental issues.
The MHRA today issued a warning to couples not to get pregnant if the man is taking the drug.
The risks of pregnant women taking it are already known and have been likened to the thalidomide scandal of the 1950s and ‘60s.
NHS doctors now have tight restrictions on prescribing it to women younger than 55.
A study in Scandinavia has found infants fathered by men taking sodium valproate, also used to treat bipolar disorder, are at risk of neurodevelopmental disorders.
Around five per cent were affected before the age of 11, compared to three per cent born to fathers taking alternative medicines.
The risk rockets to around 40 per cent if the mother takes valproate during pregnancy, and more than one in 10 have major birth defects.
Blokes on the drug have also been told not to donate sperm or get a woman pregnant for at least three months after stopping the drug.
Dr Alison Cave, chief safety officer at the MHRA, said: “Men taking valproate should be aware that there is now evidence of a potential small increased risk if their partner becomes pregnant while they are on valproate.
“We recommend that men and their partners use effective contraception.
“Patients on valproate should not stop taking their medicine unless advised to do so by a healthcare professional.”
SODIUM valproate is a prescription medicine used to treat epilepsy and bipolar disorder.
It has been available on prescription since the 1970s.
The drug works as an anti-convulsant to calm or stabilise electrical activity in the brain of epilepsy sufferers to prevent seizures, and to control manic episodes associated with bipolar disorder.
There are a number of side effects associated with sodium valproate, including hair loss, rashes, stomach upsets, weight gain, platelet reduction and increased levels of ammonia in the blood.
Sodium valproate carries high risks if taken during pregnancy and many babies have been born with physical abnormalities, autism, learning disabilities, cleft lip, heart malformations and spina bifida.
More than 20,000 Brits are estimated to have been born with severe health issues since the 1970s due to dangerous prescribing of the drug. It has been likened to the thalidomide scandal.
