Botulinum toxin type B in upper-limb poststroke spasticity: a double-blind, placebo-controlled trial.

OBJECTIVE: To determine whether botulinum toxin type B (BTX-B) is effective in controlling upper-limb spasticity.

DESIGN: A single-site, double-blind, placebo-controlled, randomized trial and open-label study.

SETTING: Outpatient.

PARTICIPANTS: Subjects with an Ashworth Scale score of 2 or more at the elbow, wrist, and fingers.

INTERVENTIONS: Subjects were injected with 10000 U of BTX-B or placebo at the elbow, wrist, and finger flexors. Main outcome measures Measures recorded at weeks 0, 2, 4, 8, 12, and 16, with a 12-week open-label study. Ashworth Scale score, a global assessment of change (GAC), adverse events and mouse neutralization antibody testing.

RESULTS: BTX-B did not decrease muscle tone in the elbow, wrist, or finger flexors at 10000 U over the 16-week period. A decrease in Ashworth Scale score for the BTX-B patient group was present at the wrist at week 2 of the double-blind study (P=.003) but was not statistically significant at other visits. In the open-label study, improvement was noted at week 4 for the elbow (P=.039), wrist (P=.002), finger (P=.001), and thumb flexors (P=.002). In the double-blind study, the Physician GAC did not reach significance. Dry mouth was reported by 8 of 9 BTX-B subjects in the double-blind study. Mouse neutralization antibodies were negative.

CONCLUSIONS: Our study does not show a significant decrease in tone from 10000 U of BTX-B. Dry mouth was common.