Single-dose effects of ibopamine hydrochloride on renal function in patients with congestive heart failure.

To examine the renal effects of ibopamine HCl we evaluated 15 patients with New York Heart Association Class II-III congestive heart failure and mild renal insufficiency (creatinine clearance [CLcr] = 45-85 ml min-1). Diuretics and vasodilators were withheld and a sodium (Na+)-restricted diet was initiated. All patients exhibited positive Na+ balance at the time of evaluation. Hourly urine volumes, urine chemistries, serum chemistries, PAH and inulin/iothalamate clearances were determined 2 h pre and 4 h post a single 200 mg oral dose of ibopamine. Effective renal plasma flow, creatinine clearance, filtration fraction, and the fractional excretion of sodium and potassium were not significantly altered postdose. A significant increase in urine output and decrease in urine osmolality were seen at all time points postdose. A significant reduction in serum potassium (2 and 3 h) and blood urea nitrogen (1, 3 and 4 h) concentrations occurred. Measurements of glomerular filtration rate by inulin or [125I]-iothalamate produced differing results in the patient groups studied. We conclude that a single dose of ibopamine does not produce significant improvements in renal function in patients with congestive heart failure, mild renal insufficiency and positive sodium balance.