Angiothrombotic Pulmonary Hypertension in Addicts

Abstract

MAO is one of the enzymes involved in the metabolism of potent biogenic amines such as l-epinephrine, l-norepinephrine, serotonin, tyramine, and dopamine.⁴ After the administration of MAO inhibitors, it is believed that there is an increase in tissue levels of l-epinephrine and l-norepinephrine. Tyramine may act as a pressor substance normally degraded by MAO, or it may provoke the release of stored catechol amines.⁵ As contrasted with pheochromocytoma, urinary 3-methoxy, 4-hydroxymandelic acid determinations have been reported as normal in those cases of cheese-induced hypertension so studied. Perhaps metanephrine or normetanephrine output must be measured in this situation, as the 3-methoxy, 4-hydroxymandelic acid pathway is dependent on MAO activity. Pargyline hydrochloride (N-benzyl-N-methyl-2-propynylamine hydrochloride) is a nonhydrazine MAO inhibitor seven to ten times as potent as iproniazid, with an effect lasting up to ten days after administration of a single oral dose. This drug was evaluated as an antihypertensive agent