Probenecid-clofibrate interaction

Abstract
Clofibric acid disposition was studied in 4 healthy men after 1 wk of clofibrate ingestion (500 mg orally every 12 h) with and without probenecid (500 mg orally every 6 h). Mean (.+-. SD) free clofibric acid plasma concentration in the 4 subjects over a dosage interval at steady state was 2.5 .+-. 0.03 mg/l before and 9.05 .+-. 1.09 mg/l after the probenecid. Probenecid reached an average plasma concentration 71.3 mg/l. No clofibric acid glucuronide was detected in plasma during either treatment. The fractions of the dose recovered in urine as clofibric acid, clofibric acid glucuronide and clofibric acid liberated after acid hydrolysis were not altered by probenecid. Probenecid may reduce renal and metabolic clearance of clofibric acid, probably by inhibiting the conjugation of clofibric acid with glucuronide.