Treating migraine with epilepsy drugs

Anti-epilepsy drugs such as Neurontin (gabapentin), Topamax (topiramate) and Depakote (divalproex) have been proven to prevent migraine headaches.  Each drug works for about half of the patients who try it.  The other half either does not get any benefits or develops side effects.  This does not seem to be that effective, but these drugs do beat placebo in blinded trials.  We also know that not all anti-epilepsy drugs work for headaches.  Tegretol (carbamazepine) was never shown to help and a study just published in Neurology confirms our impression that its cousin, Trileptal (oxcarbazepine) does not work either.  We do occasionally see good results with two other epilepsy drugs, Keppra (levetiracetam) or Lamictal (lamotrigine), but large  clinical trials proving their efficacy are lacking.