PubMed · 8405021
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D O Chanter. 1993. Parkinson's disease study.. https://doi.org/10.1007/bf02440868
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A multiple-dose study was performed to assess the pharmacokinetic profile of a new levodopa/benserazide dual-release formulation (DRF) in comparison with a conventional slow-release formulation (SRF). The study was of an open label, randomized, two-way cross-over design and was conducted in 18 subjects. Assessment of the two formulations was at day 1 (single-dose) and at day 7 after a 5-day t. i.d. pre-treatment (100 mg levodopa and 25 mg benserazide) in fasting state. The pharmacokinetic parameters reflecting bioavailability, accumulation and metabolism of levodopa were determined. The levodopa pharmacokinetics of the new DRF showed rapid absorption (tmax=1.1 h), followed by sustained levodopa plasma concentrations, similar to the SRF. Following multi-dose administration, the peak plasma concentration of the new DRF was 90% higher compared to the SFR (Cmax=2.1 and 1.1 microg/ml, respectively). The bioavailability was significantly increased by 40% (AUC0-infinity=6.1 and 4.3 microg x h/ml, respectively). The new DFR was well tolerated as shown by the low incidence of mild side effects. In conclusion, the results of this study confirmed the levodopa dual-release properties of this new levodopa/benserazide formulation.
The tremor present in a small number of patients who present with features of both Parkinson's disease (PD) and essential tremor (ET) is ill-defined. We therefore studied 8 such patients with 'atypical' tremor and compared them clinically to 11 PD and 10 ET patients in a double-blind, cross-over, placebo-controlled trial. Tremor was assessed via accelerometry and surface EMG. Tremor frequency and the acute tremorlytic response to propranolol were not useful in discriminating between groups. Over 80% of atypical and PD patients showed alternating EMG, whereas 90% of ET patients had synchronous EMG activity. Tremor amplitude improved by > 90% in 38% of atypical, 27% of PD and none of the ET patients after single-dose L-dopa/benserazide (300/75 mg), a response which was significantly different between the ET and PD groups. Failure to differentiate electrophysiologically and pharmacologically between the atypical and other groups probably relates to clinical heterogeneity in the atypical group.
A 64-year-old man was diagnosed to have Parkinson's disease when aged 42 years and since then has been treated with levodopa and benserazide (up to 875 mg daily). Bromocriptine (up to 35 mg daily) was added to the medication 9 years ago. 3 1/2 years ago he developed exertional dyspnoea (NYHA class II-III) and lost 5 kg in weight. Chest radiography demonstrated pleural effusion and interstitial pulmonary changes in both lung bases. Erythrocyte sedimentation rate was 37 mm in the first hour and the white cell count 10,400/microliters. Extensive tests failed to find malignant tumour or any infectious-inflammatory condition. As it was suspected that the pleuropulmonary changes were associated with the bromocriptine intake, it was discontinued and biperiden and selegiline substituted for it. The pleural effusion regressed almost completely within 8 weeks, and the laboratory tests pointing to inflammation disappeared completely. Clinical, biochemical and radiological tests have remained normal for the last 3 years. The clinical course makes a causal relationship between bromocriptine intake and the pleuropulmonary changes highly probable.