[Acute and chronic effects of a new oral inotropic agent, ibopamine hydrochloride, on hemodynamic and metabolic responses to ergometer exercise in patients with severe congestive heart failure].

The hemodynamic and metabolic effects of ibopamine, an orally active 3,4-diisobutylic ester of N-methyl-dopamine, at rest and during exercise, were evaluated in 8 patients with severe congestive heart failure, initially at 2 hrs after oral 100 mg and after 4 weeks of maintenance therapy (100 mg, 3 times a day). At rest, a single dose of ibopamine increased CI, SVI and SWI, and reduced PCWP, PAm, RA and PVR. These beneficial hemodynamic effects were maintained during supine bicycle exercise: CI and SVI increased markedly (p less than 0.05) and PCWP, PAm, RA and SVR increased at a lower extent (p less than 0.05) after ibopamine than on control conditions. After chronic therapy with the drug, LVDd and CTR decreased (p less than 0.05) and exercise tolerance time increased (p less than 0.01). HR, BPm, double product, norepinephrine, epinephrine, renin activity, aldosterone and lactate/pyruvate did not change significantly after administration of ibopamine. Clinical responses after 4 weeks of maintenance therapy were good in 4 cases and fair in 1 case. No adverse effects were observed. Therefore, ibopamine seems to have not only a positive inotropic action, but also a potent vasodilating action, leading to both afterload and preload reduction and so to be useful for the treatment of severe congestive heart failure at rest and during exercise after acute and chronic therapy with the drug.