title: Absence of relationships between L-dopa plasma levels and therapeutic effect in Parkinson's disease treated with L-dopa.
abstract: The plasma concentration of dopa was studied in 15 parkinsonian patients after a single administration of L-dopa. The study was undertaken in order to determine if correlation between plasma dopa concentration and clinical performance as a result of the tests carried out before and after a single dose of dopa, was present. Our data confirm the absolute absence of correlation between dopa levels in plasma and clinical improvement during long-term treatment. Moreover, clinical responses to the performance tests were not related to the concentration of circulating L-dopa in the plasma. Therefore dopa levels cannot be useful in clinical practice but only for the prevention of too high concentrations of plasma L-dopa which often cause a few side-effects.
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D004341:Drug Evaluation; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood / Q000188:drug therapy*; D013997:Time Factors
chemical_list: D007980:Levodopa