Topiramate versus amitriptyline in migraine prevention: A 26-week, multicenter, randomized, double-blind, double-dummy, parallel-group noninferiority trial in adult migraineurs

Objective: The primary objective of this study was to compare the efficacy and tolerability of topiramate and amitriptyline in the prophylaxis of episodic migraine headache. Methods: This was a 26-week, multicenter, randomized, double-blind, double-dummy, parallel-group noninferiority study. Adults with 3 to 12 migraines per month were randomized in a 1:1 ratio to receive an initial dose of 25 mg/d of either topiramate or amitriptyline, subsequently titrated to a maximum of 100 mg/d (or the maximum tolerated dose). The primary efficacy outcome was the change from prospective baseline in the mean monthly number of migraine episodes. Secondary efficacy variables included changes from the prospective baseline phase to the end of the double-blind phase in the mean monthly (28-day) rate of days with migraine, mean monthly rate of days with headache (migraine and nonmigraine), mean monthly rate of acute abortive medication use, mean monthly migraine duration, and mean monthly migraine severity. Additional secondary efficacy variables included changes in the mean monthly severity of migraine-associated symptoms (photophobia, phonophobia, and nausea), change in the mean monthly frequency f migraine-associated vomiting, and response rates (based on monthly migraine days and total headache days). The Migraine-Specific Quality of Life Questionnaire (MSQ) and the Weight Satisfaction Scale Questionnaire, which measures subjective satisfaction with current weight, were administered. Treatment-emergent adverse events (TEAEs) were monitored through the end of double-blind treatment. Results: The intent-to-treat population included 331 subjects (172 topiramate, 159 amitriptyline; 84.9% female; 84.6% white; mean [SD] age, 38.8 [11.0] years; mean weight, 77.1 [20.1] kg) who provided at least 1 efficacy assessment. The least squares mean (LSM) change from baseline in the mean monthly number of migraine episodes was not significantly different between the topiramate and amitriptyline groups (-2.6 and -2.7, respectively; 95% CI, -0.6 to 0.7). There were no significant differences between treatment groups in any of the prespecified secondary outcome measures. Subjects receiving topiramate had a significantly greater improvement in mean functional disability scores during migraine attacks compared with amitriptyline (LSM change: -0.33 vs -0.19; 95% CI, -0.3 to 0.0; P = 0.040) and in the role function-restrictive, role function-preventive, and emotional function domains of the MSQ (P = 0.012, P = 0.014, and P = 0.029, respectively). Subjects receiving topiramate had a mean weight loss of 2.4 kg, compared with a mean weight gain of 2.4 kg in subjects receiving amitriptyline. Subjects in the topiramate group reported an overall improvement from baseline in weight satisfaction, whereas the amitriptyline group reported an overall deterioration in weight satisfaction (P < 0.001, topiramate vs amitriptyline). TEAEs of mild or moderate severity were reported in 118 subjects (66.7%) in the topiramate group and 112 subjects (66.3%) in the amitriptyline group. Among the most common TEAEs (reported in ±5% of subjects during the double-blind phase) in the topiramate group were paresthesia (29.9%), fatigue (16.9%), somnolence (11.9%), hypoesthesia (10.7%), and nausea (10.2%). The most commonly reported TEAEs in the amitriptyline group were dry mouth (35.5%), fatigue (24.3%), somnolence (17.8%), weight increase (13.6%), dizziness (10.7%), and sinusitis (10.7%). Conclusions: In this noninferiority study, topiramate was at least as effective as amitriptyline in terms of reducing the rate of mean monthly migraine episodes and all prespecified secondary efficacy end points. Topiramate was associated with improvement in some quality-of-life indicators compared with amitriptyline and was associated with weight loss and improved weight satisfaction.