Fig. 2From: The crossover design for migraine preventives: an analyses of four randomized placebo-controlled trialsHeadache days per 4 weeks in relation to treatment sequence (square: Placebo first, n = 80; circle: Active treatment first, n = 96). Data from the study published in 2015 (the ALCAR-study) were omitted from this analysis due to lack of efficacy vs. placeboBack to article page