Advisors to the US regulator have declared that epilepsy treatments carry an increased risk of increased suicidal tendencies in patients but those risks are not big enough to warrant a black box warning.

A joint meeting of the peripheral and central nervous system & psychopharmacologic drugs advisory committees have voted unanimously that 11 anti-seizure medications can cause increased risks of suicidal thought. These include Pfizer’s Neurontin (gabapentin) and Lyrica (pregabalin), as well as GlaxoSmithKline’s Lamictal (lamotrigine), UCB’s Keppra (levetiracetam) and Abbott Laboratories’ Depakote (valproate).

However the panellists have voted 14-4 against suggestions previously made by the US Food and Drug Administration that the aforementioned drugs should carry a black box warning. Before the meeting, the agency had said it would seek a boxed warning for the drugs, following a review of 199 studies which found that patients on these treatments were more likely to have suicidal thoughts and behaviours than those on placebo (0.43% versus 0.22%).

The FDA had noted that the effect was rare and more research is required before a link can be confirmed, a view the committees appear to have agreed with. Furthermore, “if we have good drugs that are working, we have to be very careful about scaring patients into not taking them," said Rochelle Caplan, a professor of psychiatry at University of California, Los Angeles and one of the panellists.

The FDA usually follows the advice of its advisory panels, but could still implement the boxed warning. However, the makers of the drugs, many of which already carry information about suicidal thinking, will be hoping that it is not the case. Epilepsy treatments brought in more than $10 billion in 2007, according to data from IMS Health.