The pharmacokinetics and metabolic fate of the antihyperlipidemic drug acifran were assessed after a single oral dose of the14C‐labeled drug to healthy male volunteers. Peak serum acifran and radioactivity concentrations were attained 1 to 2 hours after dosing, and the drug was eliminated with a half‐life of 1.6 hours. Virtually all of the recovered dose was excreted in the urine. All of the serum and urinary radioactivity was caused by unconjugated acifran. In patients with moderate chronic renal failure, the binding of acifran to plasma proteins was decreased, and the plasma concentrations of total and unbound drug were greater than those of healthy subjects. Renal failure substantially reduced the plasma and renal clearance of total and particularly of unbound acifran, moderately reduced its volume of distribution, and increased its elimination half‐life from 1.4 to 1.7 hours to 5.7 hours. The results show that acifran is very well absorbed, is rapidly eliminated, is excreted in the urine, and does not undergo any detectable biotransformation in healthy human subjects.Clinical Pharmacology and Therapeutics(1990)47,50–56; doi:10.1038/clp