INCREASED TOXICITY OF HIGH-DOSE FUROSEMIDE VERSUS LOW-DOSE DOPAMINE IN THE TREATMENT OF REFRACTORY CONGESTIVE-HEART-FAILURE

Objective: To evaluate the safety and efficacy of low-dose dopamine, h igh-dose furosemide, and their combination in the treatment of refract ory congestive heart failure, Methods: Twenty consecutive patients wit h refractory congestive heart failure were randomized to receive intra venous low-dose (4 mu g/kg/min) dopamine combined with low-dose (80 mg /day) oral furosemide (group A; rt = 7), intravenous low-dose dopamine with medium-dose furosemide (5 mg/kg/day through continuous intraveno us administration; group B; n = 7), or high-dose furosemide (10 mg/kg/ day through continuous intravenous administration; group C; n = 6). Re sults: The three groups showed similar improvement in signs and sympto ms of congestive heart failure, urinary output (2506 +/- 671 ml/24 hr, mean +/- SD) and weight loss (3.3 +/- 2.3 kg) after 72 hours of thera py. Mean arterial blood pressure (MAP) decreased by 14% +/- 8% and 15% +/- 6% in groups B and C, respectively, but increased by 4% +/- 15% i n group A (p = 0.017). Renal function deteriorated significantly in gr oups B and C: creatinine clearance decreased by 41% +/- 23% and 42% +/ - 23%, respectively, but increased by 14% +/- 35% in group A (p = 0.00 74). MAP decrease was positively correlated with the decrease in creat inine clearance (r = 0.7; p = 0.0007), Patients in group B and C had m ore hypokalemia than group A, Two patients in group C sustained acute oliguric renal failure and one patient in group B died suddenly while sustaining severe hypokalemia, Conclusion: Combined low-dose intraveno us dopamine and oral furosemide have similar efficacy but induce less renal impairment and hypokalemia than higher doses of intravenous furo semide taken either alone or with low-dose dopamine, The renal impairm ent induced by intravenous furosemide is probably related to its hypot ensive effect in patients with refractory congestive heart failure.