Treatment of motor fluctuations in Parkinson's disease with an oral sustained-release preparation of L-dopa: clinical and pharmacokinetic observations.

Ten patients with idiopathic Parkinson's disease and severe motor-fluctuations participated in an open inpatient trial comparing the efficacy of standard L-Dopa/benserazide (Madopar) treatment with that of an oral sustained-release preparation (Madopar HBS) combined with the standard drug. Clinical assessments of the patients' parkinsonian disabilities were performed daily by one of the investigators and subjects kept self-scoring "on-off" diaries throughout the trial. Plasma concentrations of L-Dopa were followed during both types of therapy in five cases using standard high performance liquid chromatography technique. Sustained-release L-Dopa treatment led to a reduction in end-of-dose deterioration and on-off swings in six patients and doses needed averaged 1.6-fold of previous standard L-Dopa. Drug-induced dyskinesias decreased in one case with sustained-release therapy, remained unchanged in three, and increased in six cases when compared with conventional L-Dopa. Plasma levels of L-Dopa were more stable with the sustained-release preparation in four of five patients. During subsequent outpatient follow-ups of up to 4 months, three of the six responders in this study continued to obtain benefit from the trial drug. It is concluded that oral sustained-release L-Dopa treatment can reduce response-fluctuations in patients with Parkinson's disease.