Effect of the contrast medium meglumine amidotrizoate on renal extraction of para-amino hippurate after injection into the renal vein.

The effect of the contrast medium meglumine amidotrizoate (AngiografinR) on the renal extraction of para-amino hippurate (EPAH) was studied in 24 patients with suspected or previous renin-dependent hypertension. A single injection technique for administration of PAH was used and in eight additional patients the relationship between the arterial concentration of PAH and EPAH was studied over a period of 30 min after the injection. No change in EPAH with decreasing arterial concentration of PAH was found. After injection of 26 g of contrast medium (40 ml) into the renal veins of 18 of the 24 patients, a small (6%) but significant decrease in EPAH was observed. There was no significant difference in the decrease in EPAH between kidneys with increased and normal renal vein plasma renin activity. In the remaining six patients, the contrast medium (20 ml) was injected into one renal vein only, and blood samples were repeatedly drawn from both kidneys over a period of 30 min after injection. A decrease in EPAH was observed in both the injected and contralateral kidney; the decrease lasted for at least 20 min, with a maximum 1 min after injection. It is concluded that meglumine amidotrizoate injected into the renal vein causes a reduction of EPAH. Therefore, a contrast medium such as meglumine amidotrizoate should be avoided before determining the renal extraction of PAH.