Antiepileptic Drug Therapy in Migraine Headache

Severe migraine affects more than 28 million Americans. It is associated with episodic as well as long-term disability and suffering, yet it is underdiagnosed and undertreated. Acute treatments have advanced considerably, ignited by sumatriptan and the subsequent triptans; unfortunately migraine prevention has lagged far behind. There are no great migraine preventives! No migraine preventive agent studied in good randomized, double blind, placebo-controlled trials proved to be 50% better than placebo. Migraine trials typically focus on episodic migraine, a milder, gentler type of migraine that is selected for low frequency, lack of daily headaches, no preventive need, and previous failure to no more than a few preventive agents. These features are not typical of the usual migraine patient seen in most neurologic practices, thus the results of clinical trials may not carryover to real world situations. Treatment of frequent, chronic, or pervasive migraine is inadequate, and never has been studied in randomized controlled trials. Traditional migraine preventives, eg, beta-blockers, calcium channel blockers, and tricyclic antidepressants, are often ineffective in difficult or complicated populations. The antiepileptic drugs represent a category of pharmaceutics that target the neuronal instability and central hyperexcitability of migraine, and, through these actions, may be more effective than traditional preventives. Episodic migraine attacks are associated with peripheral and central sensitization; however, if attacks are frequent, severe, or long lasting, this sensitization may increase the risk of developing daily headaches. If antiepileptic drugs have an effect on central sensitization, perhaps mediated via glutamate inhibition or gamma-aminobutyric acid potentiation, it is appropriate to use these agents early in migraine treatment, particularly in the highly comorbid patient, possibly in conjunction with agents that antagonize the 5HT2 receptor. This report reviews the best currently available evidence on antiepileptic drugs in the prevention of episodic migraine, and tabulates potential drug-drug and cytochrome P450 interactions. All antiepileptic drugs presented are effective in migraine prevention. However, deciding on the best agent for each individual patient will require recognizing comorbidity and assessing antiepileptic drug pharmacodynamics, tolerability, and safety.