Effect of anticholinergic drugs on gastro-intestinal absorption of L-DOPA in rats and in man

Sergio Algeri, Chiara Cerletti, Maria Curcio, Paolo Lucio morselli, Luigi Bonollo, Giuseppe Buniva, Mario Minazzi, Giancarlo Minoli

Research output: Contribution to journalArticlepeer-review


Plasma L-DOPA levels in rats receiving L-DOPA by the oral route were decreased by the concomitant administration of trihexyphenidyl. Following systemic L-DOPA administration no differences were observed between control of trihexyphenidyl-treated rats. Effects similar to those of trihexyphenidyl were observed with atropine. These results indicate that trihexyphenidyl decreases L-DOPA gastrointestinal absorption probably by delaying gastric emptying. The presence in humans of this interaction between the two antiparkinsonian drugs was suggested by similar findings made either in a group of normal volunteers or in a group of parkinsonian patients. These observations suggest that at the clinical level in selected cases the concomitant administration of trixyphenidyl to patients receiving L-DOPA may decrease the therapeutic of L-DOPA by reducing its gastrointestinal absorption.

Original languageEnglish
Pages (from-to)293-299
Number of pages7
JournalEuropean Journal of Pharmacology
Issue number2
Publication statusPublished - 1976


  • Anticholinergics
  • Antiparkinson drugs interaction
  • L-DOPA absorption
  • L-DOPA plasma levels
  • Trihexyphenidyl

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Pharmacology


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