A double-blind, placebo-controlled study with a subsequent open-label phase was conducted in 354 patients with
Parkinson's disease (PD) and motor fluctuations under individually adjusted therapy with
levodopa. During the double-blind phase 174 patients received
pramipexole and 180 placebo. In agreement with previous studies,
pramipexole treatment improved UPDRS sum scores of parts II and III by 30% and off times by approximately 2.5 hours per day. Differences between the treatment groups became significant at a daily dose of 0.75 mg of
pramipexole dihydrochloride. We, furthermore, performed post hoc analyses with respect to
resting tremor and depression. Patients with pronounced
resting tremor derived a clear benefit from
pramipexole treatment compared with placebo. In addition,
pramipexole significantly improved the subitems motivation/initiative and depression in a subpopulation with increased Unified
Parkinson's Disease Rating Scale I scores at the time of inclusion. There were 262 patients who were subsequently enrolled into the open-label study featuring a maximum duration of up to 57 months. Statistical analysis revealed good long-term efficacy and tolerability of
pramipexole. Overall, only a low prevalence of somnolence was found. In summary, this study provides additional level I evidence of the usefulness of
pramipexole, suggests a particular tremorlytic and a possible antidepressant action of this compound, and addresses for the first time its efficacy and safety during long-term administration in advanced PD.