[Comparative study on nephrotoxicity of ionic and non-ionic contrast agents for drip infused urography]

The effects on renal function of an ionic and hyperosmolaric contrast agent (diatrizoate) and a non-ionic and slightly hypertonic agent (iohexol) for drip infused urography were compared on 60 patients with normal renal function. Urine samples were collected before and 30 minutes after drip infusion of contrast agent, and analyzed for albumin (ALB), gamma-glutamyl transpeptidase (gamma-GTP), N-acetyl-beta-glucosaminidase (NAG), beta 2 microglobulin (beta 2MG) and creatinine (CRE). The urinary excretion of proteins and enzymes was compared with urinary CRE. gamma-GTP, NAG and beta 2MG increased significantly after infusion of diatrizoate. gamma-GTP and beta 2MG increased significantly after infusion of iohexol. Excretion of ALB, gamma-GTP, NAG and beta 2MG was significantly higher after infusion of diatrizoate than after iohexol. The urinary concentration of CRE was significantly lower after infusion of diatrizoate than after iohexol. The degree of renal damage after urography was no related to the appearance of allergy to the contrast agent or age of patient. Therefore, the non-ionic and slightly hyperosmolaric iohexol may be less toxic to the kidneys than the ionic and hypertonic diatrizoate. This nephrotoxicity after drip infused urography is thought to be related mainly to the osmolarity of contrast agent.