Pramipexole in routine clinical practice - A prospective observational trial in Parkinson's disease

Objective: The mixed dopamine D-2/D-3 receptor agonist pramipexole is effective as monotherapy in early Parkinson's disease and as adjunctive therapy in advanced disease. Clinical trials suggest that the benefits of pramipexole may extend beyond the relief of motor symptoms (akinesia, rigidity and tremor at rest) to amelioration of depressive symptoms in Parkinson's disease. The aim of this study was to confirm the beneficial effects of pramipexole on the core symptoms of Parkinson's disease (with a focus on tremor), as well as to assess its antidepressant activity, during routine clinical practice. The study also aimed to demonstrate the practicability of the Snaith-Hamilton Pleasure Scale (SHAPS-D), the Tremor Impact Scale (TIS) and the Short Parkinson's Evaluation Scale (SPES) under conditions of routine clinical practice. Study design: This was a prospective observational study. Patients: Data for 657 outpatients with Parkinson's disease were collected from German hospitals and specialist practices. The majority of patients were in Hoehn & Yahr stage 11 or III and were receiving levodopa. Methods: Pramipexole (Sifrol(R)) was initiated at a dosage of 0.375 mg/day (using a three-times-daily schedule) and titrated upwards, as required, at weekly intervals over a 4-week period to a maximum dosage of 4.5 mg/day (three times daily). Clinical evaluation was performed at baseline, at the end of the titration phase and at the end of maintenance therapy. Patients were assessed via the German questionnaire versions of the physician-assessed SPIES, the self-evaluated TIS and the SHAPS-D. Changes in scale scores were evaluated nonparametrically, using the Wilcoxon-matched pairs test. Crombach's alpha was used as a measure for item consistency. Results: Pramipexole significantly improved SPIES subscores for motor symptoms, complications of therapy, psychological status and activities of daily living. Pramipexole also reduced the detrimental effect of tremor on activities of daily living and social interactions, as assessed by patients via the TIS. As indicated by the results of the SHAPS-D questionnaire, pramipexole significantly reduced anhedonia in patients who had associated depression. Internal consistency of SPES subscales was found to be unaltered between the initial evaluation and follow-up. Likewise, internal consistency for TIS and SHAPS-D was demonstrated. Pramipexole was well tolerated and accepted by the vast majority of physicians and patients. Conclusion: In addition to ameliorating the core symptoms of akinesia and rigidity in Parkinson's disease, pramipexole improves tremor and depressive symptoms in routine clinical practice. The SPES, TIS and SHAPS-D were found to be useful instruments with validity in this study.