Botulinum Toxin Type A as a Migraine Preventive Treatment

Abstract

Objective.—To assess the safety and efficacy of botulinum toxin type A (BOTOX; Allergan, Inc) in the prevention of migraine. Background.—Current migraine preventive therapies are often unsatisfactory because of their limited efficacy, adverse effects, and drug interactions. Botulinum toxin type A injections often reduce the pain associated with conditions such as cervical dystonia, achalasia, rectal fissures, and myofascial pain syndrome. An open‐label, noncontrolled study of botulinum toxin type A suggested benefits for patients with migraine. Design and Methods.—This was a double‐blind, vehicle‐controlled study of 123 subjects with a history of two to eight moderate‐to‐severe migraine attacks per month, with or without aura. Participants were randomized to receive single administrations of vehicle or botulinum toxin type A, 25 U or 75 U, injected into multiple sites of pericranial muscles at the same visit. During a 1‐month baseline period and for 3 months following injection, subjects kept daily diaries in which they recorded migraine frequency, migraine severity, and the occurrence of migraine‐associated symptoms. Results.—Compared with vehicle treatment, subjects in the 25‐U botulinum toxin type A treatment group showed significantly fewer migraine attacks per month, a reduced maximum severity of migraines, a reduced number of days using acute migraine medications, and reduced incidence of migraine‐associated vomiting. Both the 25‐U and 75‐U botulinum toxin type A groups were significantly better than the vehicle group on subject global assessment. Botulinum toxin A treatment was well tolerated, with only the 75‐U treatment group exhibiting a significantly higher rate of treatment‐related adverse events than vehicle. Conclusions.—Pericranial injection of botulinum toxin type A, 25 U, was found to be a safe treatment that significantly reduced migraine frequency, migraine severity, acute medication usage, and associated vomiting.