title: Levodopa availability improves with progression of Parkinson's disease.
abstract: BACKGROUND
  Previous pharmacokinetic trials with standard levodopa formulations showed a different behaviour of levodopa degradation in plasma of patients with Parkinson's disease (PD) in various stages.
  
  
  OBJECTIVE
  To investigate associations between levodopa plasma levels in relation to the scored intensity of PD.
  
  
  METHODS
  We administered water soluble 100 mg levodopa and 25 mg benserazide to 50 PD patients, taken off medication for at least 12 hours, and assessed the levodopa plasma concentrations during an 180 minutes period under standardised conditions.
  
  
  RESULTS
  The computed area under the curve (AUC) values of levodopa plasma levels were significant higher in advanced PD patients. PD rating scores significantly correlated to the AUC outcomes and the maximum levodopa plasma concentration.
  
  
  CONCLUSIONS
  Levodopa availability improves with progression of PD. This may result from deteriorated peripheral activity of levodopa metabolising enzymes or an increasing enteric dysfunction with subsequent better duodenal levodopa absorption or both.
authors.affiliation: Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Gudrunstr. 56, 44791 Bochum, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Woitalla
authors.forename: Oliver
authors.initials: O
authors.lastname: Goetze
authors.forename: Jeong I
authors.initials: JI
authors.lastname: Kim
authors.forename: Alice B
authors.initials: AB
authors.lastname: Nikodem
authors.forename: Wolfgang E
authors.initials: WE
authors.lastname: Schmidt
authors.forename: Horst
authors.initials: H
authors.lastname: Przuntek
authors.forename: Thomas
authors.initials: T
authors.lastname: Müller
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000978:Antiparkinson Agents / Q000097:blood* / Q000627:therapeutic use; D019540:Area Under Curve; D002851:Chromatography, High Pressure Liquid; D018450:Disease Progression; D005260:Female; D006801:Humans; D007980:Levodopa / Q000097:blood* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood* / Q000188:drug therapy; D012720:Severity of Illness Index; D013223:Statistics as Topic; D013997:Time Factors
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa