[Beta-blockers and migraine]

Five beta-blocking agents are effective as long-term prophylactic treatment of migraine: propranolol, metoprolol, timolol, atenolol and nadolol. Propranolol has been most extensively studied and proved effective in 19 of 21 controlled trials. The optimal dose should be determined on a case-by-case basis, by increasing the daily dosage gradually. Among the properties of beta-blockers, the only one which appears to be correlated--albeit negatively--with effectiveness on migraine is intrinsic sympathomimetic activity (ISA): drugs without ISA are effective against migraine whereas partial agonists are not. The mode of action of beta-blockers in migraine is still poorly understood; one of the most cogent current hypotheses involves reduction of brain catecholaminergic hyperactivity.