Longitudinal assessment of the dose consistency of botulinum toxin type A (BOTOX) for cervical dystonia.

Botulinum toxin type A (BoNT/A) is the principal therapy for patients with cervical dystonia. Repeated treatments over many years are required in most cases. This retrospective review evaluates the dose of BoNT/A used to treat cervical dystonia and the interval between treatments during a 2-year observation period. Outcomes data were abstracted from the medical records of 172 patients at 3 different sites who had received BoNT/A between January and December 1998. A total of 1059 treatments were assessed. Mean per-treatment doses throughout the 2-year study ranged from 241.80 to 254.07 units. The mean interval between treatments was 108.48 days during the first year of observation and 114.14 days during the second year. These findings indicate that doses of and intervals between BoNT/A treatments for cervical dystonia were consistent throughout 2 years of observation.