Inhibition of Renal Creatinine Secretion by Cimetidine in Humans

Abstract
The renal clearance of inulin (Clin), 14C-creatinine (Cl14C-cr) and endogenous creatinine (Clcr) were measured in 6 healthy subjects before and after a single i.v. bolus of cimetidine (5 mg/kg). The initial Cl14C-cr/Clin ratio (mean .+-. SD) was 1.68 .+-. 0.17; this fell to a nadir of 1.35 .+-. 0.18 soon after cimetidine was infused and rose again as the drug was excreted. This is the 1st cationic drug to show substantial inhibition of tubular secretion of creatinine in humans.