Radiocontrast-induced nephrotoxicity and urinary alpha-glutathione S-transferase levels: effect of amlodipine administration.

AIMS

The exact pathogenesis and prophylaxis concerning radiocontrast-induced nephrotoxicity (RCIN) was unclear. Short-acting calcium antagonists were used to prevent RCIN. This study was designed to evaluate the role of a long-acting calcium antagonist (amlodipine) administration by determining serum creatinine (SCre) levels and 24 hour urinary excretion rates of glutathione S-transferase alpha (GST-alpha) which has a selective localization only to proximal tubular epithelium.

METHODS

In a prospective trial, 29 outpatients (19 M, 10 F) undergoing coronary angiography were randomized and either amlodipine 10 mg/day (n = 15) or placebo (n = 14) were administered prior to angiography and continued thereafter. All patients had normal basal renal function and none of them had any risk factor for RCIN. A low osmolar, nonionic contrast media (iopamidol 76%) was administered to all patients. Creatinine clearance (CCre), SCre and 24-hour urinary GST-alpha levels were measured before, 24 hours and 7 days after angiography.

RESULTS

SCre and 24 hour urinary GST-alpha values increased on 24th hour following the angiography in both groups (p < 0.017 and 0.001, respectively). Pretreatment with amlodipine created no difference in both variables (p > 0.05).

CONCLUSIONS

A reversible tubular dysfunction occurs following radiocontrast administration which was manifested by an increase in urinary GST-alpha excretion rates. Pretreatment with a long acting calcium antagonist amlodipine has no effect on the course of enzyme excretion and alteration observed in SCre.