title: The long-duration response to L-dopa in the treatment of early PD.
abstract: OBJECTIVE
  To investigate the long-duration response (LDR) to L-dopa resulting from different regimens of L-dopa.
  
  
  BACKGROUND
  In clinical practice, L-dopa is usually administered without considering the LDR due to the drug. Moreover, it has not been established whether in early PD a multiple daily intake of small doses of L-dopa may induce a sustained LDR.
  
  
  METHODS
  Twenty-four patients with early PD underwent a double-blind, crossover trial, comparing three different 15-day treatment periods with L-dopa: treatment A (250 mg every 24 hours); treatment B (250 mg every 8 hours); and treatment C (125 mg every 8 hours). After completion, 20 patients underwent a subsequent open-label randomized trial with prolonged treatments (250 mg every 24 hours or 125 mg every 8 hours) up to 3 months. LDR was measured at the end of each treatment.
  
  
  RESULTS
  All patients achieved a sustained LDR after treatments A and B, whereas only 17% of patients reached a sustained LDR after treatment C. Overall, the LDRs resulting from treatments A and B had similar magnitude and were larger than the LDR deriving from treatment C. After 3 months of prolonged treatments, only three of 10 patients treated with 125 mg every 8 hours increased their LDR, whereas all 10 patients treated with 250 mg every 24 hours had a maximal and stable LDR.
  
  
  CONCLUSIONS
  Sustained LDR to L-dopa is dependent on the amount of the single doses of the drug. A regimen scheduling small, divided doses during the day, as done in clinical practice, is a questionable therapy for the achievement of a sustained LDR.
authors.affiliation: Institute of Neurology, University of Catanzaro, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Zappia
authors.forename: R L
authors.initials: RL
authors.lastname: Oliveri
authors.forename: D
authors.initials: D
authors.lastname: Bosco
authors.forename: G
authors.initials: G
authors.lastname: Nicoletti
authors.forename: D
authors.initials: D
authors.lastname: Branca
authors.forename: M
authors.initials: M
authors.lastname: Caracciolo
authors.forename: I D
authors.initials: ID
authors.lastname: Napoli
authors.forename: A
authors.initials: A
authors.lastname: Gambardella
authors.forename: A
authors.initials: A
authors.lastname: Quattrone
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage* / Q000009:adverse effects; D002230:Carbidopa / Q000008:administration & dosage / Q000009:adverse effects; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination / Q000187:drug effects; D010300:Parkinson Disease / Q000175:diagnosis / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa; D002230:Carbidopa