Beneficial effect of clonidine on spasticity antagonized by baclofen in a stroke patient

Although Clonidine has recently been described as a useful antispasticity agent, to our knowledge there has not been a previous report of clonidine's antispasticity effect antagonized by baclofen. Using a 0-5 Modified Ashworth Scale to evaluate the right knee extensor tone in a 74-year-old man 5 months following a left middle cerebral artery stroke, tone improved from 3 to 1 on Clonidine 0.6 mg daily in divided doses. The day after addition of baclofen at 15 mg daily in divided doses, tone increased to 4. Baclofen was withdrawn with a decrease in tone to 2. Baclofen alone at the above dose resulted in tone comparable to the clonidine-free baseline. Treatment with Clonidine alone was resumed, and the expected reduction in hypertonicity was again observed. Possible mechanisms of action for baclofen antagonizing the beneficial effect of Clonidine on spasticity after stroke are presented and discussed.