Clinical profile of botulinum toxin A in patients with chronic headaches and cervical dystonia: a prospective, open-label, longitudinal study conducted in a naturalistic clinical practice setting.

BACKGROUND AND OBJECTIVES: Some evidence for the efficacy of botulinum toxin A as a preventive treatment for chronic primary headaches has been reported in randomized, controlled clinical studies. This study investigated the clinical profile of botulinum toxin A in a naturalistic clinical practice setting in a population of patients with cervical dystonia associated with chronic headache and a history of migraine.

METHODS: This was a prospective, open-label, longitudinal study. Following a prospective run-in period, eligible patients were given three sets of botulinum toxin A injections at 8- to 12-week intervals over a 16- to 24-week period and were monitored for 3 months after the final injections. Efficacy was assessed in terms of headache-related disability (using the Migraine Disability Assessment [MIDAS] questionnaire), pain and emotional function (using the Short Pain Inventory [SPI]), quality of life (QOL, using the Short-Form-36 [SF-36] questionnaire) and patient-assessed headache frequency and severity, and medication use and its effectiveness. Safety was assessed as adverse events. The primary endpoint was the change in MIDAS score from baseline following treatment with botulinum toxin A.

RESULTS: Twenty-four patients took part in the study and 17 (71%) completed the study. There were significant improvements in headache-related disability (MIDAS score), pain and emotional function (SPI), QOL (SF-36), headache frequency and medication use following treatment with botulinum toxin A (p < 0.05 for all endpoints). An efficacy response occurred within 8 weeks of treatment initiation and was maintained throughout the study duration. Botulinum toxin A was generally well tolerated.

CONCLUSIONS: This study demonstrated that botulinum toxin A is an effective and well tolerated preventive treatment for chronic headache in patients with cervical dystonia and a history of migraine. These results warrant further investigation in a large, randomized, controlled study.