RESUMO
The aim of the present investigation was to evaluate the acute hemodynamic effects of a single oral dose of 200 mg ibopamine (SB-7505), the 3,4-diisobutyryl ester of N-methyldopamine (epinine) in 11 patients with congestive heart failure (CHF) and to compare the influence of dopamine infusion and oral ibopamine on left ventricular function. Free and conjugated epinine plasma levels were also investigated in these patients and in a group of healthy volunteers to evaluate the correlation between epinine plasma levels and hemodynamic effects. The oral administration of 200 mg ibopamine to patients with CHF, increased cardiac index (+35%) and reduced peripheral and pulmonary vascular resistance (-29% and -26%) without modifying heart rate and systemic or pulmonary arterial pressure. The hemodynamic effect reached its maximum at about 90 min and was still present at 240 min. Ibopamine at a dose of 200 mg elicited similar effects to those observed with dopamine, 2-4 micrograms/kg/min. The pharmacokinetic behaviour of ibopamine in these patients was similar to that observed in a group of healthy volunteers. Free epinine plasma levels peaked at 30-60 min and decreased rapidly, thus showing a shorter time course than the hemodynamic effects.
