NEW YORK, July 20 (Praxis Press) Radiographic contrast agents can cause a reduction in renal function, possibly due to the effects of reactive oxygen species, and the usefulness of antioxidants in preventing this effect is unclear. Tepel and colleagues prospectively studied 83 patients with chronic renal insufficiency undergoing computed tomography with the contrast agent iopromide (see paper). Patients were randomly assigned to receive either the antioxidant, acetylcysteine, or a placebo, before and after receiving the contrast agent. They found that only one of the patients in the acetylcysteine group, and nine of the patients in the placebo group showed impaired renal function as measured by serum creatinine concentration. Administration of the antioxidant acetylcysteine prevents reduction in renal function induced by the contrast agent, iopromide, in patients with.