Botulinum neurotoxin for the treatment of migraine and other primary headache disorders

Botulinum toxin A (BoNT-A), a neurotoxin, is effective for treating a variety of involuntary muscle contraction disorders, including cervical dystonia, blepharospasm, and hemifacial spasm. Recently, clinical findings suggest that BoNT-A may inhibit pain associated with migraine and other headache types. A number of retrospective, open-label chart reviews and three placebo-controlled, double-blind trials have demonstrated that localized injections of BoNT-A significantly reduce migraine frequency, severity, and migraine-associated disability. There are currently four randomized, placebo-controlled clinical trials in progress evaluating the efficacy, optimal dosing, and side effect profile of this toxin as a novel treatment for migraine and other headache types. These studies may provide further evidence that BoNT-A is an effective option for the preventive treatment of migraine.