Iopentol in patients with chronic renal failure: its effects on renal function and its use as glomerular filtration rate parameter.

Iopentol (mean dose 0.42 g I kg-1) was administered for abdominal aortography and pelvic angiography in 10 patients with advanced non-diabetic chronic renal failure (S-creatinine 672 +/- 259 mumol l-1, mean +/- SD). Renal glomerular function measured as creatinine clearance and plasma clearance of [99Tcm]-diethyl-enetriaminepentaacetic acid (DTPA) was unchanged by iopentol, as also was urinary excretion of the renal tubular enzymes N-acetyl-beta-glucosaminidase (NAG) and alkaline phosphatase (ALP). The elimination of iopentol from serum and urine was delayed, and detectable serum and urine concentrations were found 5 days after administration of the contrast medium. Creatine clearance was 47% higher than the corresponding renal iopentol clearance. Plasma iopentol clearance, measured as the total area under the plasma concentration curve, was 40% higher than renal iopentol clearance because of extrarenal elimination of iopentol. We conclude that abdominal aortography with iopentol can be performed without effects on renal glomerular or tubular function parameters in patients with advanced renal failure. If iopentol is used for measurement of glomerular filtration rate (GFR) in this group of patients, one should measure renal clearance, as plasma clearance overestimates GFR.