Contrast-induced nephropathy: are there differences between low osmolar and iso-osmolar iodinated contrast media?

It is acknowledged that high osmolar contrast media are more nephrotoxic than low (LOCM) or iso-osmolar contrast media (IOCM). However, it remains contentious whether the IOCM are less nephrotoxic in comparison with LOCM. This article reviews published clinical studies that investigated this issue and demonstrates there are no conclusive data to indicate that there is a definite difference in renal tolerance between LOCM and IOCM. All these agents are potentially nephrotoxic in patients with advanced renal impairment. In these patients the smallest possible dose of IOCM or LOCM should be used in addition to adequate hydration to minimize the risk of contrast nephropathy.