Objectives.—To review the efficacy of botulinum neurotoxin type A (BoNT-A) in the preventive treatment of refractory headache.

Background.—Even after receiving expert care, some patients with refractory headache continue to have high disability and persistent headaches.

Methods.—Clinical records and headache calendars of 100 patients fulfilling the following inclusion criteria were reviewed: (1) age from 18 to 65 years; (2) primary headache with previous failure of at least four preventive treatments; and (3) have received BoNT-A and have been followed for at least 6 months after the BoNT-A injections. BoNT-A (100 units) was diluted in 4-cc normal saline. The muscles injected included some or all of the following: frontalis, temporalis, corrugator, procerus, occipitalis, semispinalis, splenius capitis, trapezius, cervical paraspinalis, and sternocleidomastoid. Migraine-related disability was assessed using the Migraine Disability Assessment (MIDAS) questionnaire.

Results.—There was a statistically significant reduction of the frequency of headache days 1 month after BoNT-A was administered (14.2 vs 28.2 days at the baseline, P < .001), which was maintained through the 3 months of study; similarly, a significant reduction in the headache index (22.3 vs 40.3, P < .001) and number of severe days with headache per month (2.6 vs 7.4, P < .001) were found at 1 month and maintained through the 3 months of study. MIDAS scores were reduced from 34.5 at baseline to 15.9 at 3 months (P < .001). A similar pattern was found in those overusing versus nonoverusing acute medication, though the response was more dramatic in the nonoverusing subgroup.

Conclusion.—BoNT-A may play a role in the preventive treatment of refractory headache. A significant number of patients showed decrease in clinically important measurements of their headaches as well as reduced headache-related disability with this treatment. Prospective, controlled studies must be considered for severely disabled, refractory patients.