Treatment of chronic tension-type headache with botulinum toxin A: a randomized, double-blind, placebo-controlled multicenter study.

A beneficial effect of botulinum toxin on tension-type headache was reported in open-label studies but scientifically rigorous clinical studies are lacking. Therefore we conducted a prospective, multicenter, randomized, double-blind, placebo-controlled trial. Multiple pericranial muscles of 112 patients with chronic tension-type headache were treated either with 500 mouse units of botulinum toxin (Dysport) or with placebo. The diagnoses were made strictly following the International Headache Society criteria. Co-existence of migraine was an exclusion criterion. Injections were made following a fixed scheme and not adjusted to the patient's symptoms. Patients kept a headache diary that was used to calculate the area under the headache curve of 6 weeks before and 12 weeks after the treatment as the main effect measure. Secondary effect measures were the number of days with headache, the number of days with intake of analgesics, the duration of the nocturnal sleep, and the Beck Depression Inventory score. There were no significant differences between the verum group and the placebo group in any of these variables. Seven patients of the verum group had transient weakness of the eyelids, the neck, or both, indicating that a higher dose than used in this study does not seem sensible for the treatment of headache. The statistical power of the study was high enough to warrant the conclusion that there is no clinically significant effect of botulinum toxin A on chronic tension-type headache.