Pharmacokinetics of furosemide in advanced renal failure

The pharmacokinetics of furosemide were studied in 12 patients with advanced renal failure. The elimination half-life of furosemide averaged 9.7 hours. Renal furosemide clearance was reduced, but furosemide elimination by nonrenal mechanisms was unimpaired in uremic patients without liver disease and accounted for 86% to 98% of total elimination. Nonrenal furosemide clearance also was reduced in 3 uremic patients with liver cirrhosis, and elimination half-life was prolonged to 20 hours in 1 of these patients. The diuretic response to intravenous furosemide appeared to be adversely affected by poor renal function and dehydration. Diuretic response was always less after oral than after intravenous furosemide, and the slow, intravenous infusion of this drug is recommended for maximal efficacy in uremic patients.