Treatment of headaches with botulinum toxin.

Primary headache disorders, such as migraine, chronic daily headache (CDH), and chronic tension-type headache (CTTH), are some of the most frequent disorders encountered by physicians in the outpatient setting. Chronic headache disorders cause significant morbidity and functional impairment. Despite important advances in both pharmacological and behavioral management of headache disorders, a number of patients remain treatment resistant. Botulinum toxin (BT) is emerging as a new therapeutic alternative in the preventative treatment of headaches. BT has several advantages over current prophylactic strategies, such as reduced side-effect profile and improved patient compliance. Furthermore, there have been several studies supporting the safety and tolerability of BT in the treatment of headache disorders. Although additional large-scale studies are needed to clarify clinical predictors of response as well as optimal dosing, injection sites and mechanism of action, BT has demonstrated efficacy in the treatment of migraines and CDH. The evidence for the treatment for CTTH is less compelling.