Hemodynamic Studies of a Monoamine Oxidase Inhibitor, DL-Serine-N 2 -Isopropylhydrazide (RO 4-1038)

Hemodynamic studies were performed on 11 patients with severe diastolic hypertension before and after the chronic administration of the monoamine oxidase inhibitor, RO 4-1038. Although postural hypotension was more marked, the blood pressure decreased significantly in the supine position as well. The hypotensive effect was attributable almost solely to decreased total peripheral resistance and was unrelated to changes in cardiac output, blood volume, or sodium space. Renal plasma flow and glomerular filtration rate were unchanged. Evidence is presented which suggests that the decrease in blood pressure was not caused by adrenergic blockade. If RO 4-1038 is a representative monoamine oxidase inhibitor then its hemodynamic action is unique among the clinically useful hypotensive drugs.