Increased dosage of carbidopa in parkinsonian patients on low carbidopa-levodopa regimen. Effect of levodopa bioavailability

M. Contin, R. Riva, P. Martinelli, G. Procaccianti, A. Baruzzi

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The effect of a 2.5-fold increase in daily carbidopa intake on the bioavailability of levodopa was studied in six patients with Parkinson's disease on a low chronic regimen of carbidopa-levodopa (Sinemet) at the fixed ratio of 1:10. The extent of levodopa absorption, expressed as the area under the 11-h plasma levodopa concentration-time curve (AUC(0-11 h)), was not enhanced by the higher carbidopa dose. A significant increase in the AUC was found for the levodopa metabolite 3-O-methyldopa at the higher carbidopa intake. Clinical performances of individual patients were identical with both carbidopa-levodopa ratios. From these data, an adequate inhibition of peripheral decarboxylation and hence a good bioavailability of levodopa may be expected in patients taking low doses of carbidopa-levodopa, using currently available commercial preparations.

Original languageEnglish
Pages (from-to)75-81
Number of pages7
JournalClinical Neuropharmacology
Issue number1
Publication statusPublished - 1989


ASJC Scopus subject areas

  • Clinical Neurology
  • Pharmacology (medical)
  • Neuroscience(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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