Evidence based migraine prophylactic drug therapy

Prophylactic drug therapy is a major component of overall migraine manageme nt. However, because we do not know how currently used prophylactic drugs e xert their beneficial effects in migraine, their use is based primarily on clinical trials. In general, prophylactic drugs are indicated when patients have three or more attacks a month and symptomatic medication use alone is not satisfactory. The choice of drug must be individualized, and is influe nced by contraindications, potential side effects, the need to treat associ ated symptoms like tension-type headache and insomnia, and drug cost. Wheth er an individual patient will respond to a given drug cannot be predicted, but there are varying degrees of scientific evidence supporting the use of each prophylactic drug in migraine. This evidence is best for metoprolol, d ivalproex, amitriptyline, atenolol, flunarizine and naproxen. Based on plac ebo-controlled crossover studies, it would appear that at least some prophy lactic drugs exert the greater part of their prophylactic effects very quic kly, and that these also disappear very quickly once the drug is stopped. T his may not apply to all prophylactic drugs and more research is needed. Mo re well designed clinical trials are needed to guide our use of migraine pr ophylactic drugs. Although clinical experience is useful, placebo responses and Variations in the migraine tendency over time can make interpretation of this experience difficult. Major advances will likely only occur once th e pathogenesis of migraine and the made of action of the prophylactic drugs is better understood.