Enhanced pressor sensitivity to oral tyramine challenge following high dose selegiline treatment.

Blood pressure and heart rate responses to oral tyramine have been measured in healthy volunteers before and after administration of the selective monoamine oxidase B inhibitor selegiline at high dosage (30 mg/day). Treatment brought about a 2 to 4-fold increase in tyramine sensitivity and a concomitant small but significant reduction in plasma 4-hydroxy-3-methoxyphenylglycol concentration, pointing to the emergence of some degree of monoamine oxidase A inhibition. It is suggested that patients treated with selegiline 30 mg/day or more should be placed on a tyramine-free diet.