Drugmaker GlaxoSmithKline is informing pregnant women of a possible association between an anti-epileptic medication and cleft palate or cleft lip in newborns. The statement, issued Tuesday after discussions with Health Canada, says new data from a pregnancy registry suggest an association between taking Lamictal (lamotrigine) in the first trimester of pregnancy, and increased risk of cleft lip and/or palate in the baby.
In the general population, oral clefts are among the most common major birth defects, occurring at rates of 0.5 to 2.16 per 1,000 births, according to GlaxoSmithKline. The pregnancy registry showed three cases of cleft palate and two cases of cleft lip in infants born to 564 users of the drug, a rate of 8.9 per 1,000.
Patients taking the drug should notify their doctors if they become pregnant or intend to become pregnant during therapy with Lamictal, the statement says.
“Although pregnant women and their unborn children may face significant health risks from uncontrolled epilepsy, Lamictal should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.”
But stopping or starting the drug should only be done after consulting with a doctor, the statement says.
“Sudden discontinuation of anti-eplieptic therapy may lead to breakthrough seizures with serious consequences for both the mother and the fetus and should be avoided.”
Peter Schram, a spokesman for the drug company, said other discontinuation symptoms can include rashes, dizziness, headaches, nausea and blurred vision.
The drug has been marketed in Canada since 1995 for the treatment of epilepsy. It acts on sodium channels to stabilize the membrane of neurons in the brain and to prevent the excessive release of chemicals that carry electrical impulses between neurons, said GlaxoSmithKline.
Health Canada spokesman Chris Williams noted that some other anti-epileptic drugs on the market in Canada currently contain warnings about birth defects, and some don’t.
“However, the product monographs of all anti-epileptic drugs carry the general statement that the drug should only be used in pregnancy if the potential benefit to the mother outweighs the potential risk to the fetus,” he said.
The company has sent its new safety information to health-care professionals.