title: Chronic levodopa intake increases levodopa plasma bioavailability in patients with Parkinson's disease.
abstract: Previous pharmacokinetic trials with standard levodopa formulations showed a different behavior of levodopa degradation in plasma of patients with Parkinson's disease (PD) in various advanced stages. The objective of this trial was to compare levodopa plasma metabolism in PD patients with and without previous long-term levodopa intake after oral intake of a dispensable levodopa/benserazide formulation (DLB). The over a 150 min interval computed area under the curve values of levodopa plasma levels after DLB administration were significantly (ANCOVA: F(1,19) = 7.88, P = 0.01) higher in PD patients with chronic levodopa treatment compared to patients without prior levodopa treatment. The maximum plasma levodopa concentration did not differ (ANCOVA: F(1.19) = 1.17, P = 0.29). Long-term levodopa administration results in an increased levodopa plasma bioavailability in PD patients.
authors.affiliation: Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Gudrunstrasse 56, 44791 Bochum, Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Muhlack
authors.forename: Dirk
authors.initials: D
authors.lastname: Woitalla
authors.forename: Jacob
authors.initials: J
authors.lastname: Welnic
authors.forename: Svenja
authors.initials: S
authors.lastname: Twiehaus
authors.forename: Horst
authors.initials: H
authors.lastname: Przuntek
authors.forename: Thomas
authors.initials: T
authors.lastname: Müller
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000978:Antiparkinson Agents / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use; D019540:Area Under Curve; D001545:Benserazide / Q000008:administration & dosage; D001682:Biological Availability; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000097:blood; D004333:Drug Administration Routes; D004334:Drug Administration Schedule; 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; D014443:Tyrosine / Q000031:analogs & derivatives
chemical_list: D000978:Antiparkinson Agents; D014443:Tyrosine; D007980:Levodopa; D004295:Dihydroxyphenylalanine; D001545:Benserazide; C008404:3-methoxytyrosine