Role of botulinum toxin in migraine therapy

Abstract

AbstractBotulinum toxin effectively blocks the release of acetylcholine from motor nerve terminals. Thus, botulinum toxin injections are well established in the treatment of disorders in which patients are impaired by involuntary muscle contractions. A remarkable pain reduction was frequently observed in these patients, and in vitro studies showed that botulinum toxin reduces not only the release of acetylcholine, but also the release of neuropeptides involved in pain perception. It was therefore hypothesized that botulinum toxin may help patients with pain not caused by muscular contractions, such as migraine or chronic daily headache, which includes chronic migraine. So far, the results of randomized, double‐blind, placebo controlled trials on botulinum toxin in a total of 2,612 patients with migraine or with chronic daily headache were published. A superiority of botulinum toxin compared with placebo injections could not clearly be confirmed in any of the studies. One hypothesis derived from these results was that subgroups of patients with migraine can be defined in whom botulinum toxin may be efficacious. This hypothesis awaits confirmation. Interestingly, the efficacy of both botulinum toxin and placebo injections was found to be significant and similar to the efficacy of established oral migraine treatment. This finding may help explain the enthusiasm that followed the first open‐label use of botulinum in patients with migraine. Drug Dev Res 68:397–402, 2007. © 2008 Wiley‐Liss, Inc.