Pharmacodynamics of the hypotensive effect of levodopa in parkinsonian patients

R. P. Irwin, J. G. Nutt, W. R. Woodward, S. T. Gancher

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Blood pressure effects of i.v. levodopa were examined in parkinsonian patients with stable and fluctuating responses to levodopa. The magnitude of the hypotensive effect of levodopa was concentration dependent and was fit to an E(max) model in fluctuating responders. Stable responders demonstrated a small hypotensive response. Baseline blood pressures were higher in fluctuating patients; a higher baseline blood pressure correlated with greater hypotensive effects. Antiparkinsonian effects of levodopa temporally correlated with blood pressure changes. Phenylalanine, a large neutral amino acid (LNAA) competing with levodopa for transport across the blood-brain barrier, reduced the hypotensive and antiparkinsonian effects of levodopa. We conclude that levodopa has a central hypotensive action that parallels the motor effects in fluctuating patients. The hypotensive effect appears to be related to the higher baseline blood pressure we observed in fluctuating patients relative to stable patients.

Original languageEnglish (US)
Pages (from-to)365-374
Number of pages10
JournalClinical neuropharmacology
Volume15
Issue number5
DOIs
StatePublished - Jan 1 1992

Keywords

  • Amino acid transport
  • Blood pressure
  • Blood- brain barrier
  • Levodopa
  • Parkinson disease
  • Pharmacodynamics

ASJC Scopus subject areas

  • Pharmacology
  • Clinical Neurology
  • Pharmacology (medical)

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