EFFECTS OF IBOPAMINE IN COMBINATION WITH FUROSEMIDE ON RENAL-FUNCTION IN PATIENTS WITH CHRONIC CONGESTIVE HEART-FAILURE

The effects of ibopamine and furosemide on renal function given alone and in combination at single doses were studied in 6 men and 6 women aged 45 to 73 years with chronic congestive heart failure of NYHA class II. After 3 days of dietary stabilization, the patients received either ibopamine 200 mg, furosemide 40 mg, or furosemide 40 mg plus ibopamine 200 mg with 2-day washout between treatments, according to a double-blind, balanced three-way crossover design using all possible treatment sequences. On each treatment day urine collections were performed at 2-hourly intervals from 2 h before to 6 h after dosing, and urine volume and Na+, K+, Cl-, and creatinine concentrations were measured for every period. The patients received a standardized breakfast 3 h before treatment and then were allowed 250 ml tap water to drink before starting each urine collection period. Venous blood samples were taken before breakfast and midway between each urine collection period for analysis of serum Na+, K+, Cl-, creatinine, and glucose. Heart rate, blood pressure, and physical signs were recorded 2, 1 h, immediately before, and then 0.5, 1, 2, 3, 4, 5, and 6 h after treatment. At the same times the patients were asked for any symptoms. The time course of the diuretic effect of furosemide 40 mg was consistent with the data reported by other authors. Post-treatment values of urine vlume and of Na+, K+, and Cl- excretions calculated for the cumulated 6-h urine collection showed no statistically significant differences between furosemide and furosemide plus ibopamine, while significant differences were observed between furosemide and ibopamine and between furosemide plus ibopamine and ibopamine. No statistically significant difference was found for creatinine clearance among the 3 treatments, though a slight increase was observed after the administration of ibopamine 200 mg. No significant differences among treatments were found at any time considered for serum Na+, K+, Cl-, creatinine, and glucose as well as for heart rate and blood pressure, with the exception of serum K+ at the last sampling time when mild though statistically significant differences were found between ibopamine and furosemide and between ibopamine and furosemide plus ibopamine. No patient experienced any adverse effects during the course of the study.