Tremor and dopamine agonists.

Although all dopaminergic drugs are effective in reducing tremor, no single drug has been shown to be clearly superior in the treatment of tremor. Levodopa produces a mean improvement of 30 to 50% in the Unified Parkinson's Disease Rating Scale (UPDRS) subtest for rest tremor. Comparable improvement is achieved with the dopamine agonists. Dopamine agonists are particularly well suited for patients with newly diagnosed tremor-predominant disease and no cognitive impairment, but they are also useful in advanced patients with tremor that is refractory to levodopa and anticholinergics. The response of tremor to pharmacotherapy is variable, and clinicians must be prepared to try all of the available drugs before concluding that surgery is the only alternative.