title: Steady plasma levodopa concentrations required for good clinical response to CR-4 in patients with 'on-off'.
abstract: Ten patients with Parkinson's disease and severe motor fluctuations were given Sinemet (25/100) for 4 weeks followed by 4 weeks of Sinemet (CR-4). After each drug preparation was optimized, patients were rated by neurological examination and plasma levodopa (LD) measured at hourly intervals (9 a.m.-4 p.m.). For the group as a whole, variations throughout the day of plasma LD and clinical state were no different on the 2 formulations. Three patients whose fluctuations responded well to CR-4 had either much less variable plasma LD levels on CR-4 or were able to maintain plasma LD above a minimum threshold. In severe fluctuators, a major benefit from CR-4 can be expected only in those patients who can maintain steady plasma LD levels above the threshold for achieving the 'on' state.
authors.affiliation: Department of Neurology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick.
authors.forename: D M
authors.initials: DM
authors.lastname: McHale
authors.forename: J I
authors.initials: JI
authors.lastname: Sage
authors.forename: P K
authors.initials: PK
authors.lastname: Sonsalla
authors.forename: R E
authors.initials: RE
authors.lastname: Heikkila
authors.forename: R C
authors.initials: RC
authors.lastname: Duvoisin
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000493:pharmacokinetics / Q000627:therapeutic use; D002230:Carbidopa / Q000493:pharmacokinetics* / Q000627:therapeutic use; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations / Q000493:pharmacokinetics / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007980:Levodopa / Q000493:pharmacokinetics* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy*
chemical_list: D000978:Antiparkinson Agents; D003692:Delayed-Action Preparations; D004338:Drug Combinations; C009265:carbidopa, levodopa drug combination; D007980:Levodopa; D002230:Carbidopa