FUROSEMIDE KINETICS AND DYNAMICS IN RATS AND HUMANS

1. Increasing doses of furosemide (F) were given intravenously to rats and humans and initial pharmacokinetics and pharmacodynamics were compared. 2. Weight-related initial renal excretion rate of F was twice as high in rats and serum concentration at 30 min was twice as high in humans (P < 0.01). 3. Volume of distribution for F was 44% larger in rats (P < 0.01). 4. Maximal weight-related diuretic and natriuretic responses were, like the theoretical maximal efficiency, 5-6 times higher in the rat. The potency was 230 times lower in the rats. 5. On a molecular basis species differences in kinetics disappeared when standardization was based on ERPF and species differences in dynamics disappeared when standardization was based on GFR.