Pergolide: multiple-dose pharmacokinetics in patients with mild to moderate Parkinson disease

The primary objective of this study was to describe the pharmacokinetics of oral pergolide in patients with mild to moderate Parkinson disease using a new high-performance liquid chromatography-tandem mass spectrometry assay. A secondary objective was to investigate the relationship between plasma concentrations and efficacy. Fourteen patients with a diagnosis of Parkinson disease completed this multicenter, open-label, dose-escalating study. Pergolide was administered for 58 days, using increasing daily doses from 0.05 mg daily up to 1 mg three times daily and then tapering the dose. The steady-state pharmacokinetic profile and motor score were determined at dose levels of 0.25, 0.5, and 1 mg three times a day and during elimination after the last dose. Pergolide was absorbed with a median time to maximum concentration of 2 to 3 hours across the dose range. Systemic exposure appeared to increase proportionally with dose over the range of 0.25 to 1 mg three times daily within a patient, but there was a large variability in exposures between patients (interpatient coefficients of variation were 56.4% for the area under the curve). Pergolide was widely distributed (volume of distribution, approximately 14,000 L) and was eliminated with a mean half-life of 21 hours. Motor scores improved as both peak plasma pergolide concentrations and exposure increased. No unexpected safety concerns were identified. Pergolide is absorbed relatively quickly into the systemic circulation, has a large apparent volume of distribution, and has a relatively long half-life (mean, 21 hours). This prolonged half-life is of particular interest, given the current hypothesis that more continuous dopaminergic receptor stimulation may reduce motor complications in patients with Parkinson disease.

Psychomotor and cognitive effects of piribedil, a dopamine agonist, in young healthy volunteers

Piribedil is a dopamine agonist acting on D2 and D3 central nervous system dopamine receptors. This drug has been administered to 12 young healthy male volunteers (age 22 +/- 2 years) according to a single center randomized, double-blind, two ways cross-over, placebo controlled trial, including a washout period of one week. Placebo and piribedil were administered by a single intravenous infusion over 2 h (3 mg). Psychomotor performance and cognitive functions were assessed through a standardized and computerized psychometric tests battery and a continuous electroencephalogram (EEG) mapping. Piribedil improved simple reaction time (P=0.02), immediate (P=0.045 and 0.004), and delayed free recall (P=0.05), dual coding test (P=0.02) and increased theta and fast beta waves on the EEG (P < 0.05 and 0.001, respectively). No deleterious effect was observed on the tests exploring attention and concentration via the other procedures. It is concluded that a single intravenous perfusion of piribedil 3 mg improves alertness and the information processing speed within the central nervous system, in healthy volunteers.

Choosing the right dopamine agonist for patients with Parkinson's disease

Dopamine receptor agonists (DA) are assuming an increasing importance in the treatment of both early and advanced symptoms of Parkinson's disease (PD). However, choosing the right DA for patients with PD unfortunately remains more a pragmatic medical art than a science. The aim of this review is to provide a realistic point of view on the strengths and weaknesses of five DAs: bromocriptine, ropinirole, pergolide, pramipexole and piribedil. This has been done by analysing their respective: (1) flexibility in PD, i.e. in monotherapy, in early and in late combination with levodopa; (2) safety profile and (3) titration schedule. These five DAs are not evenly matched regarding these three criteria. The differences observed highlight the therapeutic value of piribedil, which has a flexible indication, adapted to all stages of PD, a safer profile and the most simple initiation schedule.