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Botulinum toxin type A for migraine: first, do no harm

FEATURED REVIEW Given its uncertain efficacy, at best only modest, botulinum toxin type A is simply too risky a treatment for migraine. It is better to focus on fine tuning of standard prophylaxis.
Full review (4 pages) available for download by subscribers.

Abstract

  • Headache prevention in adults with chronic migraine is based first on oral drug therapy, preferably with propranolol, and on tapering off possible analgesic overuse.

  • Botulinum toxin type A injections in head and neck muscles is now authorised for this purpose in the United Kingdom. It has been used off label for several years.
     
  • Clinical evaluation in this indication is based on two placebo-controlled double-blind trials with identical designs. A total of 1384 patients underwent two sessions of intramuscular injections of botulinum toxin type A or placebo, 3 months apart, into at least 31 specific sites in the head and neck. Compared to baseline, patients who received botulinum toxin in one trial (but not in the other) experienced a statistically significant reduction in headache frequency at the end of the study, but the results are undermined by methodological issues.
     
  • Botulinum toxin type A has not been compared with preventive oral therapy. An inherently unreliable indirect comparison suggests that botulinum toxin type A is clearly less effective than oral propranolol.
     
  • In its other approved indications, botulinum toxin type A has been linked to deaths and muscle paralysis distant from the injection site, leading to swallowing difficulties and respiratory disorders.
     
  • Some patients enrolled in clinical trials of botulinum toxin type A experienced transient worsening of their migraine and headache (9.3%, versus 5.8% of patients receiving placebo injections), exaggerated paralytic effects, and muscle pain and stiffness.  
     
  • In practice, given its uncertain efficacy, at best only modest, botulinum toxin type A is simply too risky a treatment for migraine. It is better to focus on fine tuning of standard prophylaxis.

©Prescrire 1 December 2011

"Botulinum toxin type A for migraine. First, do no harm" Prescrire Int 2011; 20 (122): 287-290. (Pdf, subscribers only)

 
Download the full review.
Pdf, subscribers only