Tyramine pressor sensitivity changes during deprenyl treatment

Trey Sunderland, Edward A. Mueller, Robert M. Cohen, David C. Jimerson, David Pickar

Research output: Contribution to journalArticlepeer-review

67 Scopus citations


Deprenyl has previously been reported to be a selective monoamine oxidase (MAO) type B inhibitor, which is associated with little or no enhancement of the pressor effects of tyramine. Employing an intravenous steady-state tyramine infusion technique, the effects of different doses of deprenyl and, for comparison, the mixed inhibitor tranlcypromine on the pressor response to tyramine were studied in 11 depressed patients. After 3 weeks of treatment, deprenyl produced dose-proportionate increases in tyramine sensitivity at all three doses (10, 30, and 60 mg/day) when compared to placebo baseline tyramine responses. While only a modest (3.7-fold) increase in tyramine sensitivity was found with the 10 mg/day deprenyl dose, the increase in tyramine sensitivity at the 60 mg/day dose of deprenyl (22-fold) approached that found with tranylcypromine. Reductions in plasma 3-methoxy,4-hydroxyphenylglycol (MHPG), used as a possible index of in vivo MAO-A inhibition, were highly correlated with increases in tyramine pressor sensitivity (r=0.82). The data suggest that deprenyl acts as a relatively selective MAO-B inhibitor at low doses, but that this selectivity is lost at higher doses, resulting in a significant "crossover" inhibition of MAO-A and increased tyramine pressor sensitivity.

Original languageEnglish (US)
Pages (from-to)432-437
Number of pages6
Issue number4
StatePublished - Aug 1985
Externally publishedYes


  • Blood pressure
  • Monoamine oxidase (MAO)
  • Plasma MHPG
  • Platelet MAO activity
  • Selective MAO-B inhibitor
  • Tyramine
  • Tyramine pressor sensitivity

ASJC Scopus subject areas

  • Pharmacology


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