Daily pharmacologic prophylaxis of episodic migraine

Patients with high frequencies of migraine, high disability or impact from migraine, and frequent users of acute migraine medications merit migraine prophylaxis in the form of daily medication. The choice of migraine-preventive medication is best based on the opportunity to treat multiple concomitant disorders as well as migraine with 1 medication. Migraine-preventive medications, at best, work in approximately half of patients to reduce migraine frequency by about 50%, so careful establishment of expectations with use of headache diaries is crucial for therapeutic success. Treatment should always begin with low doses and be gradually increased to optimal dosing, which then should be maintained for 2 to 3 months to evaluate effectiveness. Medications with the best evidence for efficacy in the prevention of migraine are amitriptyline, propranolol, timolol, valproate, and topiramate. Although all migraine preventive medications are nonspecific and have multiple potential mechanisms for their effects, they often share a tendency to reduce central neuronal hyperexcitability by inhibiting excitatory neurotransmitters, such as glutamate and norepinephrine, increasing inhibitory tone via GABA, reducing the likelihood of cortical spreading depression, or favorably altering channelopathies or mitochondriopathies thought to be intrinsic to migraine pathophysiology.