The efficacy of clonidine and levetiracetam for treating tics in Tourette syndrome was compared in a 15-week randomized, double-blind, flexible dose, crossover study at Johns Hopkins Hospital, Baltimore, MD. In 10 subjects, ages 8-27 years, the mean Total Tic Score improved significantly with clonidine compared with levetiracetam, whereas the Yale Tic Severity Scale did not change. With levetiracetam, none of the measures showed a change. The initial dose of clonidine was 0.05 mg, twice daily, and levetiracetam 10 mg/kg/day, divided twice daily. The mean maximum dose for clonidine was 0.20 mg/day, and for levetiractam, 1,150 mg/day. The mean Tic Score and Tic Severity Scale scores at baseline were similar in treatment groups. Sedation occurred with clonidine in 5 patients and irritability as a side effect of levetiracetam in 4. Clonidine reduced the frequency of tics but levetiracetam had no effect. 
COMMENT. Although this study found a statistically significant improvement in Total Tic Score with clonidine, the authors considered the benefit of limited clinical significance. Previous reports demonstrate a range of results with clonidine, from 0 to 75% reduction in tics (authors reference). As the authors comment, additional direct comparison studies, including placebo, in a larger series would be more meaningful.