BACKGROUND: The influence of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) on contrast-induced renal toxicity has been poorly studied. Nevertheless, it is a common practice in many centers to stop these drugs before coronarography. Our goal was to study whether renal function was affected in patients taking ACEIs or ARBs and undergoing a coronary angiogram. METHODS: Patients on ACEIs or ARBs (n=17) and those not on ACEIs or ARBs (n=18) admitted for a coronary angiogram underwent glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) assessment either by isotopic clearances (51Cr-EDTA and MAG3) or inulin and paraimmuno-hippurate clearances 24 hours prior to and immediately after coronary angiogram. RESULTS: Median percentage GFR changes induced by the injection of contrast medium during coronary angiogram were -9% (interquartile range -19% to +3%) in the control group and -1% (interquartile range -9% to +39%) in the ACEI/ARB group. Mean ERPF remained stable after coronarography in the control group (median change -8%; interquartile range -18% to +6%) and increased slightly in the ACEI/ARB group (median change +9%; interquartile range -17% to +60%). The median percentage difference in EPRF change was not statistically significant between the 2 groups (p=0.18). CONCLUSIONS: Inhibition of the renin-angiotensin system is not associated with a decline in renal function in patients receiving contrast media, and there is no need to interrupt this treatment prior to coronary angiogram.