Drug treatment of migraine: Part II. Preventive therapy.

In most cases, successful preventive therapy for migraines requires daily medication for months or years. Perimenstrual use of a preventive agent is a common exception. Preventive therapy is usually undertaken in patients who have more than two headache episodes per month or those very much disabled by headaches. Beta blockers are usually the first choice for preventive therapy, and amitriptyline is also commonly used. Despite widespread use of calcium channel blockers for prevention of migraine, their benefits are controversial. Although effective for prevention of migraine, methysergide and phenelzine are usually relegated to last-resort use because of potentially serious side effects. The migraine patient who is refractory to standard preventive therapy may have rebound headache related to overuse of abortive migraine medications, or concomitant psychopathology.