The effects of cimetidine on creatinine excretion, glomerular filtration rate and tubular function in renal transplant recipients

Abstract

The renal clearance of endogenous creatinine (CCr), sodium (CNa) and lithium (CLi) was determined before and after a single intravenous bolus of cimetidine in nine renal transplant recipients. The glomerular filtration rate (GFR) was measured with 125I-iothalamate clearance (CTh). The initial CCr of 65 ml/min (median) was reduced to a nadir of 46 ml/min (p<0.01) during the first 2 h after infusion of cimetidine. GFR remained unchanged, and thus the fractional clearance of creatinine (CCt/CTh) was reduced from 1.43 (median) to 1.03 (p<0.01). CNa and the fractional excretion of sodium decreased throughout the study (p<0.05); CLi was unchanged. In conclusion cimetidine, when measured during 1-h clearance periods, interferes with tubular creatinine secretion in the denervated kidney of transplant recipients without affecting the glomerular filtration rate or proximal tubular flow. This suggests that on-going cimetidine treatment must be taken into account when graft function is evaluated by the CCr alone.

Key Words:

• cimetidine
• clearance of creatinine
• clearance of lithium
• glomerular filtration rate
• renal transplantation