Acts by direct vasodilation of pulmonary and systemic arterial vascular beds and by inhibition of platelet aggregation. IV infusion in clients with pulmonary hypertension results in increases in cardiac index and SV and decreases in pulmonary vascular resistance, total pulmonary resistance, and mean systemic arterial pressure. Is rapidly hydrolyzed at the neutral pH of the blood as well as by enzymatic degradation.
Metabolites are less active than the parent compound.
Chronic use in those with CHF due to severe LV systolic dysfunction and in those who develop pulmonary edema during dose ranging. Abrupt withdrawal or sudden large decreases in the dose may cause rebound pulmonary hypertension. Use caution in dose selection in the elderly due to the greater frequency of decreased hepatic, renal, or cardiac function, as well as concomitant disease or other drug therapy. Use with caution during lactation. Safety and efficacy have not been determined in children.