Pharmacokinetics of Furosemide in Patients with Congestive Heart Failure

Abstract

A pharmacokinetic study of furosomide was undertaken in 7 patients with severe congestive heart failure. The extent of oral availability, determined by the ratio of areas under the oral to i.v. plasma concentration-time curve, averaged 61%, but varied widely from patient to patient, from 34-80%. Absorption of the drug was often delayed, with a lag time before appearance in the plasma averaging 28 .+-. (SD) 15 min. The volume of distribution of furosemide (averaging 114 ml/kg) was not diminished in the presence of congestive failure and drug clearance and elimination half-lives are similar to values reported in normal subjects. Urinary flow rates 1-2 h after dosing were significantly less after oral than i.v. dosing, but flow rates over 4, 8 or 24 h after dosing were similar for both routes of administration.