Pharmacological prevention of migraine.
Although abortive treatment and nonpharmacologic interventions are effective for many if not most patients' occasional migraine attacks, patients who have frequent and/or severe attacks may benefit from preventive pharmacotherapy. This is particularly critical for those patients whose migraines are not treated effectively by acute-care medications because lack of pain control may lead to overuse syndromes that complicate further treatment. Inappropriate use of acute-care medication may contribute to chronic daily headache, tolerance to symptomatic medication, and headache refractory to all treatment. In addition, patients who increase use of acute-care medication due to lack of effect may suffer ergotism, GI problems, liver toxicity, analgesic nephropathy, drug induced-headache, and withdrawal symptoms when overused agents are withdrawn. Finally, overuse of acute-care medication may interfere with the effectiveness of preventive medication. The remainder of this article will focus on when to treat with preventive medication and which medications are currently available for prevention of migraine.