[Enzyme determination in the urine for the evaluation of kidney tolerance of the water-soluble roentgen contrast medium iopamidol].

The renal toxicity of the ionic, very hyperosmolaric megluminamidotrizoate was compared with the toxicity of the non-ionic, slightly hypertonic iopamidol after intravenous injection of 0.7 ml/kg body weight (i.e. about 300 mg iodine/ml) in a randomized study of 20 individuals with normal kidneys. Quantitative measurements of the excretion of the enzymes, lactate dehydrogenase (LDH), alkaline phosphatase (AP), and N-acetylglucosaminidase (NAG) in 24-h urine samples, serum creatinine, and the endogeneous creatine clearance were conducted to determine the possible renal damage. All 20 subjects tolerated both contrast mediums well. Reduced renal function as measured by the creatinine blood level and the endogeneous clearance did not occur. The ionic, hyperosmolaric megluminamidotrizoate++ caused significantly elevated enzymuria of NAG, AP, and LDH (P less than 0.01) following tubular irrigation, whereas iopamidol showed no significant enzymuria. Therefore, it appears that the non-ionic contrast medium, iopamidol, is less toxic for kidneys than the ionic megluminamidotrizoate.