Prescrire international
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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. ⋯ 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.