Tetrabenazine treatment for Huntington's disease-associated chorea.

Tetrabenazine (TBZ), a monoamine depleter and dopamine receptor blocker, is used to treat a variety of hyperkinetic movement disorders. The objective was to study the efficacy and tolerability of TBZ for chorea associated with Huntington's disease (HD). Nineteen patients (12 female), mean age 56.3 +/- 12.4 years (range 37-76 years) diagnosed with HD were prospectively evaluated at initial and follow-up visits using a modified Abnormal Involuntary Movement Scale (AIMS). Patients were videotaped, and the randomized videotapes were rated with the motor subset of the AIMS by two investigators who were blinded to treatment assignment. Eighteen patients completed and were rated after 5.9 +/- 3.3 months (range 2-11) at a final mean TBZ dose of 62.5 +/- 37.4 mg/day (range 25-150). The blinded videotaped motor scores showed that 15 were better on TBZ, 2 were better before TBZ, and 1 was unchanged (p < 0.001, Wilcoxon signed rank test). The mean score improved from 16.2 +/- 4.8 to 12.8 +/- 4.4. Adverse events included akathisia, insomnia, constipation, depression, drooling, and subjective weakness. All 18 of these patients have continued to take TBZ since completion of the study. TBZ was well tolerated and resulted in a significant improvement in modified AIMS scores in HD patients. These results support the use of TBZ for chorea in patients with HD.