OBJECTIVES: The purpose of the study was to examine the potential renal protective effect of low-dose dopamine in high- risk patients undergoing coronary angiography. BACKGROUND: Contrast nephropathy is prevalent in patients with chronic renal failure (CRF) and/or diabetes mellitus (DM). Decreased renal blood flow due to vasoconstriction was suggested as a contributory mechanism. Low-dose dopamine has a dilatory effect on the renal vasculature. METHODS: Sixty-six patients with mild or moderate CRF and/or DM undergoing coronary angiography were prospectively double-blindedly randomized, to either 120 ml/day of 0.9% saline plus dopamine 2 μg/kg/min (Dopamine group) or saline alone (Control group) for 48 h. RESULTS: Thirty-three Dopamine-treated (30 diabetics and 6 with CRF) and 33 Control (28 diabetics and 5 with CRF) patients were compared. Plasma creatinine (Cr) level increased in the Control group from 100.6 ± 5.2 before to 112.3 ± 8.0 μmol/liter within five days after angiography (p = 0.003), and in the Dopamine group from 100.3 ± 5.4 before to 117.5 ± 8.8 μmol/liter after angiography (p = 0.0001), respectively. There was no significant difference in the change of Cr level (°Cr) between the two groups. However, in a subgroup of patients with peripheral vascular disease (PVD), ΔCr was -2.4 ± 2.3 in the Control group and 30.0 ± 12.0 μmol/liter in the Dopamine group (p = 0.01). No significant difference occurred in ΔCr between Control and Dopamine in subgroups of patients with preangiographic CRF or DM. CONCLUSIONS: Contrast material caused a small but significant increase in Cr blood level in high-risk patients. There is no advantage of dopamine over adequate hydration in patients with mild to moderate renal failure or DM undergoing coronary angiography. Dopamine should be avoided in patients with PVD exposed to contrast medium.