This study was a multinational, multicentre, double-blind, active controlled phase III trial designed to investigate efficacy and safety of 300 mg acetylsalicyclic
acid (ASA) (n = 135) vs. 200 mg
metoprolol (n = 135) in the prophylaxis of
migraine. In total 270 (51 male and 219 female) patients, aged 18-65 years, suffering between two and six
migraine attacks per month were recruited. The main objective was to show equivalence with respect to efficacy, defined as a 50% reduction in the rate of
migraine attacks. A run-in phase was carried out with placebo for 4 weeks, followed by a 16-week
drug phase. In both treatment groups the median frequency of
migraine attacks improved during the study period, from three to two in the ASA group and from three to one in the
metoprolol group; 45.2% of all
metoprolol patients were responders compared with 29.6% with ASA. Medication-related adverse events were less frequent in the ASA group (37) than in the
metoprolol group (73). The findings from this trial show that
metoprolol is superior to ASA for
migraine prophylaxis but has more side-effects.
Acetylsalicylic acid is better tolerated than
metoprolol. Using a strict responder criterion ASA showed a responder rate comparable with the placebo rate in the literature.