Double-blind study of the activity and tolerability of cabergoline versus placebo in parkinsonians with motor fluctuations. Multicenter, placebo-controlled trial of cabergoline taken once daily in the treatment of Parkinson's disease.
The use of a dopamine agonist with a long duration of action has theoretical advantages in attempting to reduce the motor fluctuations in Parkinson's disease. We report the results of a double-blind controlled study of adding cabergoline, an ergot derivative with potent long-lasting high affinity for the D2 receptor, to levodopa therapy in 37 patients with severe fluctuations in response to treatment. Increasing dosages of cabergoline (19 patients) or placebo (18 patients) were added to each patient's stable levodopa regime. The two patient groups were similar at baseline in terms of age, disease duration, duration of levodopa treatment, and average hours "off" per day. Following incremental dose titration, patients in the cabergoline group had a significant reduction in hours "off" per day from 5.0 (SD 2.1) to 3.0 (SD 2.5), but there was no change in this measure in the placebo group [4.0 (2.2) and 3.3 (2.3) respectively]. This was not at the expense of a significant increase in dyskinesia. However, there was no difference between the groups when comparing their average Hoehn and Yahr stage of disease, and Schwab and England activities of daily living index. Cabergoline is a dopaminergic agonist relatively specific for the D2 receptor and much longer-acting than other dopamine agonists. We conducted a randomized, placebo-controlled, double-blind study of cabergoline in 188 levodopa/carbidopa-treated patients with suboptimally controlled Parkinson's disease (PD). The cabergoline patients had significantly better Activities of Daily Living (p = 0.032) and Motor Examination (p = 0.031) scores at the conclusion of the trial compared with the placebo group. The daily levodopa dose for the cabergoline patients decreased 18% compared with a 3% reduction for the placebo group (p < 0.001). The amount of time in the "on" state increased more in the cabergoline group (p = 0.022). The side-effect was similar to that seen with other dopamine agonists, and cabergoline was generally well tolerated. We conclude that cabergoline is an effective adjunct to levodopa for the treatment of PD.
In the management of the motor complications seen in Parkinson's disease, cabergoline can be used to reduce levodopa dose and modestly improve motor impairment and disability with an acceptable adverse event profile. These conclusions are based on, at best, medium term evidence.