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Cochrane Review: What is the Evidence for the Prevention of Migraines Using Botulinum toxins?


  • FDA has approved onabotulinumtoxinA as a preventative treatment for adults with chronic migraine who have 15 or more days each month with headache lasting 4 or more hours each day in people ≥18 years of age
  • Mechanism not well understood
    • May inhibit release of neuropeptides that are involved in the initiation of the migraine
  • Herd et al. (Cochrane Library, 2018) examined how Botulinum toxin type A compares to active treatment for adults with chronic or episodic migraines


  • Systematic review and meta-analysis
  • Literature search of RCTs of botulinum toxin injections into the head and neck for prophylaxis of chronic or episodic migraine in adults
  • Studies were selected that compared as follows
    • Botulinum toxin vs. placebo
    • Botulinum toxin vs. other active treatment
  • Too avoid bias, two independent researchers selected trials and extracted data
  • GRADE methods used to assess result quality


  • 90 articles describing 28 trials and 4,190 participants were included in the study
  • Botulinum toxin vs placebo
    • Botulinum toxin reduced the number of chronic migraine days per month by by 1.9 days (95% CI, -2.7 to -1.0, 2 trials, high-quality evidence)
    • Severity of migraines with botulinum was also reduced but larger trials required
    • Botulinum toxin groups had a greater risk for adverse events
      • Risk ratio (RR) 1.28, (95% CI 1.12 to 1.47; moderate-quality evidence)
    • Botulinum toxin vs other prophylactic agents
      • Individual trials reported no differences between groups for multiple efficacy measures
      • No difference was seen when comparing side effects to other oral treatments
      • Patients taking botulinum toxin were 4x less likely to stop their treatment due to adverse events compared to an alternative (P = 0.02, 2 trials, N = 119)
    • Botulinum toxin side effects were reported in approximately 60%, consisted mostly of droopy eyelid or muscle weakness (40% reported in placebo groups)


  • The quality of the evidence is limited
  • Botulinum toxin type A may reduce number of migraines in chronic migraine sufferers by 2 days a month

Learn More – Primary Sources:

Botulinum toxins for the prevention of migraine in adults