Botulinum toxin for treatment of primary chronic headache disorders.

Migraine. Since the 2002 TEC Assessment, 1 new study meeting selection criteria has appeared. Published in 2004 (n=60), this trial randomized patients to saline placebo, low-dose BTX-A, or high-dose BTX-A. No significant differences were reported at 3 months for any of 7 pain-related outcomes. The low dose of BTX-A had a lower rate of accompanying symptoms (photophobia, phonophobia, nausea and vomiting), compared with the placebo and high-dose groups. A study from 2000 (n=123) provided mixed results for the use of BTX for migraine prophylaxis. This moderately sized trial reported only short-term outcomes, and questions remain regarding the variability of effect at different time points, as well as variability of dose and injection site. Isolated findings of statistical significance favoring BTX-A in these 2 studies could be explained by chance alone and evidence is judged insufficient for conclusions.