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Efficacy of Botulinum Toxin Type A for the Prophylaxis of Episodic Migraine Headaches: A Meta‐analysis of Randomized, Double‐Blind, Placebo‐Controlled Trials
Author(s) -
Shuhendler Adam J.,
Lee Soyoung,
Siu Ms. Michelle,
Ondovcik Ms. Stephanie,
Lam Ms. Kyla,
Alabdullatif Ms. Awatif,
Zhang Ms. Xiaochu,
Machado Márcio,
Einarson Thomas R.
Publication year - 2009
Publication title -
pharmacotherapy: the journal of human pharmacology and drug therapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.227
H-Index - 109
eISSN - 1875-9114
pISSN - 0277-0008
DOI - 10.1592/phco.29.7.784
Subject(s) - migraine , placebo , headaches , botulinum toxin , medicine , randomized controlled trial , anesthesia , meta analysis , surgery , alternative medicine , pathology
Study Objective. To assess the efficacy of botulinum toxin type A in lowering the frequency of migraine headaches in patients with episodic migraines. Design. Meta‐analysis of eight randomized, double‐blind, placebo‐controlled trials. Patients. A total of 1601 patients with a history of episodic migraine headaches classified as those experiencing headaches fewer than 15 times/month over a 3‐month period. Measurements and Main Results. PubMed, Google Scholar, and the Cochrane Library were searched from inception to October 2007 in order to locate randomized, double‐blind, placebo‐controlled trials that compared the efficacy of pericranial botulinum toxin A injections with placebo in the prevention of migraines in patients with a history of episodic migraine headaches. The primary outcome of interest was change from baseline to end point in migraine frequency (number of migraines/month). A random effects model was used to combine study results, and the standardized mean difference (Cohen's d) in migraine frequency between the placebo and botulinum toxin A groups was reported. Effect sizes (d) less than 0.2 were considered small. Quality assessment was performed by using the Downs and Black scale. Eight randomized, double‐blind, placebo‐controlled clinical trials (1601 patients) presented a quantitative assessment of the efficacy of botulinum toxin A versus placebo. The overall treatment effect size of botulinum toxin A over placebo for 30, 60, and 90 days after injection was d −0.06 (95% confidence interval [CI] −0.14‐0.03, z =1.33, p=0.18), d −0.05 (95% CI −0.14‐0.03, z =1.22, p=0.22), and d −0.05 (95% CI −0.13‐0.04, z =1.07, p=0.28), respectively. Even after controlling for a high placebo effect, and after dose stratification, no significant effect of botulinum toxin A in reducing migraine frequency/month was seen over placebo. Conclusion. Botulinum toxin A for the prophylactic treatment of episodic migraine headaches was not significantly different from placebo, both from a clinical and statistical perspective.