Role of botulinum toxin A in the prophylactic treatment of migraine headaches

OBJECTIVE: To evaluate the role of botulinum toxin type A in the prophylaxis of migraine headaches. DATA SOURCES: MEDLINE (1966-July 2005), Iowa Drug Information Service (1966-July 2005), and International Pharmaceutical Abstracts (1970-July 2005) searches were performed. Key search terms included botulinum and migraine. DATA SYNTHESIS: Patients who received botulinum toxin type A injections for treatment of hyperfunctional facial lines also experienced relief of migraine symptoms, leading to further investigation. Four clinical trials and 2 retrospective chart reviews evaluating the use of botulinum toxin type A injections for the prophylactic treatment of migraines are discussed. Limitations of these trials include problems with blinding, use of different injection sites, and inconsistent dosing. CONCLUSIONS: The results of 3 double-blind, placebo-controlled trials, 2 retrospective chart reviews, and an open-label study indicate that botulinum toxin type A may be a safe and efficacious prophylactic treatment for migraine headaches.