The pharmacologic treatment of migraine may be acute (abortive, symptomatic) or preventive (prophylactic). Most migraine preventive medications were designed to treat other disorders (e.g., propranolol for hypertension, valproate for epilepsy, etc.). Preventive medication is usually given daily for months or years; however, treatment can be episodic, subacute, or chronic. The medications can be divided into two major categories: (i) Alternatives of high efficacy, which include beta-blockers, tricyclic antidepressants, and divalproex, and of lower efficacy, which include selective serotonin reuptake inhibitors, calcium channel antagonists, and non-steroidal antiinflammatory drugs, and (ii) second-line choices of high efficacy, which include methysergide and monoamine oxidase inhibitors. The choice of preventive treatment depends on the individual drug's efficacy and side effects, the patient's wants, needs, and response to prior treatment, and the presence of any comorbid or coexistent disease.