Renal excretion of iopromide and iopamidol after intravenous administration in digital subtraction angiography.

After injection of iopromide or iopamidol into a central vein in 40 patients ages 57 +/- 14 years and 57 +/- 11 years, respectively, with normal renal function, iodine concentration and total iodine excretion were determined in pooled urine over 0 to 2 hours and 2 to 24 hours after injection. Iopromide excretion of 46.4 +/- 9.8% of the dose during the first 2 hours after injection was significantly (p less than 0.05) higher than that of iopamidol, which amounted to 41.4 +/- 10.5% of the dose. This is presumably due to the fact that iopromide has lower protein binding than iopamidol. Excretion of the two nonionic contrast media up to 2 hours after injection decreased constantly with increasing age. In the case of iopromide, a mean excretion of 55% of the dose in a patient 25 years old decreased to about 40% for a patient 90 years of age (p less than 0.05). The clinical relevance of the observed differences and correlations is discussed.