Contrary to some reports, the epilepsy drug oxcarbazepine does not appear to prevent migraine, according to research published in the February 12, 2008, issue of Neurology®, the medical journal of the American Academy of Neurology.

The nearly five-month study involved 170 men and women at clinics across the United States with half of the group receiving a daily dose of oxcarbazepine; the other half took placebo. Both groups included people who had three to nine migraine attacks within a month.

Researchers found no difference between the oxcarbazepine and placebo groups in the change in the number of migraine attacks from the beginning to the end of the study.

“The results of this trial do not support preliminary data which had suggested oxcarbazepine was effective in preventing migraine,” said study author Stephen D. Silberstein, MD, with Thomas Jefferson University in Philadelphia, and Fellow of the American Academy of Neurology. “While several epilepsy drugs have been used for decades to prevent migraine, oxcarbazepine did not prevent migraine in this study despite it being shown to be safe and well-tolerated.”

Silberstein says the three epilepsy drugs that most effectively prevent migraine, topiramate, divalproex and gabapentin, have several mechanisms by which they treat migraine, including the ability to regulate a neurotransmitter known as GABA. In contrast, oxcarbazepine has no apparent activity on GABA. Silberstein says it’s possible that epilepsy drugs must be able to regulate this neurotransmitter in order to prevent migraine.

In addition, Silberstein says several factors may have contributed to the lack of response in this study, including that the participants had difficult-to-treat migraines.

Migraine is estimated to affect more than 28 million Americans at some point in their lives, costing $18 billion per year in absenteeism and impaired work function and $1 billion dollars per year in medical care costs.

The study was supported by Novartis Pharmaceuticals Corporation, maker of oxcarbazepine.