88 patients in need of prophylactic treatment for classical, common or mixed migraine of at least 2years' duration were admitted to a double-blind placebo-controlled trial of the beta1-selective adrenoceptorblocker, metoprolol. All patients initially took placebo for 1 month, during which 29 were excludedprincipally because of failure to reattend or placebo-response making active treatment unnecessary. Theremaining 59 patients were randomised to continued placebo or metoprolol 50 mg b.i.d. for 2 months.Patients after this time subjectively categorizing their responses as less than optimal changed,double-blindly, from placebo to metoprolol 50 mg b.i.d., or from metoprolol 50 mg b.i.d. to 100 mg b.i.d., fora further follow-up period of up to 3 months.
Placebo response was 40% overall, and often occurred after the first month. In the first double-blindcomparative period metoprolol reduced attack frequency significantly, and more than placebo. Severity ofattacks still occurring was not altered by either treatment. Other measures of illness were alteredconsistently with these principal findings. Consistent improvements also were seen in patients switchingfrom initial placebo therapy to metoprolol 50 mg b.i.d. for the further follow-up period, and those changingto the higher dose of metoprolol showed statistically significant further improvements, and clinicallyimportant improvements overall. Side-effects were minor and reversible.
This study gives supportive evidence of the value of metoprolol in preventing migraine attacks andsuggests that individual dosage titration can substantially enhance its efficacy. Side-effects do notsignificantly impede its use and other evidence suggests that beta1-selective blockers are to be preferredover non-selective in migraine therapy.