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.
- Antiparkinson drugs interaction
- L-DOPA absorption
- L-DOPA plasma levels
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience