多巴胺药代动力学.pdfVIP

J Neurol (2010) 257 (Suppl 2):S253–S261 DOI 10.1007/s00415-010-5728-8 Pharmacokinetics of levodopa Manuela Contin • Paolo Martinelli Springer-Verlag 2010 Abstract This paper reviews the clinically relevant low, subtherapeutic plasma concentrations. Dyskinesias determinants of levodopa peripheral pharmacokinetics and may also be related to high-levodopa, excessive plasma main observed changes in the levodopa concentration– concentrations. Recognition of the different levodopa toxic effect relationship with Parkinson’s disease (PD) progres- response patterns can be difficult on a clinical basis alone sion. Available clinically practical strategies to optimise and simultaneous monitoring of the levodopa concentra- levodopa pharmacokinetics and pharmacodynamics are tion–effect relationship may prove useful to disclose the briefly discussed. Levodopa shows particular pharmacoki- underlying mechanism and in planning the correct man- netics including an extensive presystemic metabolism, agement. Clinically practical strategies to optimise levo- overcome by the combined use of extracerebral inhibitors dopa pharmacokinetics, and possibly its therapeutic of the enzyme L-amino acid decarboxylase and rapid response, include liquid drug solutions, controlled release absorption in the proximal small bowel by a saturable formulations and the use of inhibitors of levodopa metab- facilitated transport system shared with other large neutral olism. Unfortunately, these attempts have proved so far amino acids. Drug transport from plasma to the brain is only partly successful, due to the complex alterations in mediated by the same