Continuous versus intermittent oral administration of levodopa in Parkinson's disease patients with motor fluctuations: A pharmacokinetics, safety, and efficacy study

C. Warren Olanow, Margherita Torti, Karl Kieburtz, Mika Leinonen, Laura Vacca, Paola Grassini, Adam Heller, Ephraim Heller, Fabrizio Stocchi

Research output: Contribution to journalArticle


Background: Laboratory and clinical evidence indicate that continous delivery of levodopa is associated with reduced motor complications compared to standard intermittent levodopa. Objective: To assess the pharmacokinetics and efficacy of continuous oral delivery of l-dopa/carbidopa in PD patients with motor fluctuations. Methods: Eighteen PD patients with motor fluctuations were enrolled in an open-label study comparing pharmacokinetics and efficacy measures between standard intermittent oral l-dopa/carbidopa and “continuous” oral l-dopa/carbidopa. Continuous treatment was operationally defined as sips of an l-dopa dispersion at 5- to 10-minute intervals. On day 1, patients received their usual oral l-dopa/carbidopa doses. On day 2, patients received l-dopa/carbidopa dose by “continuous” oral administration. On day 3, patients received a single dose of oral l-dopa/carbidopa followed by continuous administration of l-dopa/carbidopa. Each study period was 8 hours, and the total l-dopa/carbidopa dose administered was the same on each day. Analyses of variability were primarily-based samples drawn between 4 and 8 hours when subjects were in a relative steady state. Results: There was less variability in plasma l-dopa concentration with continuous versus intermittent oral l-dopa/carbidopa treatment (fluctuation index was 0.99 ± 0.09 vs. 1.38 ± 0.12 [P < 0.001] and coefficient of variation was 0.35 ± 0.03 vs. 0.49 ± 0.04 [P < 0.001]). Mean OFF time was decreased by 43% (P < 0.001) with continuous oral l-dopa therapy. No safety or tolerability issues were observed. Conclusions: Continuous oral delivery of l-dopa/carbidopa was associated with less plasma variability and reduced off time in comparison to standard intermittent oral l-dopa/carbidopa therapy.

Original languageEnglish
Pages (from-to)425-429
Number of pages5
JournalMovement Disorders
Issue number3
Publication statusPublished - Mar 2019



  • continous levodopa
  • motor complications
  • Pharmacokinetics

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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