Serum Concentrations of Propranolol and Migraine Prophylaxis

Since 1966, there have been numerous reports regarding the prophylactic use of various β-receptor-blocking drugs in preventing as well as treating migraine headache.1-5The mechanism by which these drugs exert their therapeutic actions in patients with migraine remains unclear and has not been conclusively attributed to β-blockade. Even less well understood are the dosage and serum concentrations associated with reliable headache prophylaxis. It is not uncommon for patients with migraine taking up to 240 mg/day of propranolol hydrochloride to continue to have frequent migraine headaches. It is likely that the wide range of dosages needed to control headaches is due to variability in both the threshold concentration needed to control headaches as well as variability in the dosage needed to achieve that target concentration. We report a case in which periodic fluctuations in propranolol hydrochloride concentrations were temporally associated with the occurrence of migraine headaches. REPORT OF A CASE