Even now, hydration is crucial for preventing CIAKI. Since CIAKI is presumed to be caused by free radical generation, N-Acetylcysteine, which is a potent free radical scavenger, is shown to be effective in preventing nephropathy. At the same time, because free radical formation is promoted by an acidic environment, bicarbonate, which alkalinizes renal tubular fluid, has been shown to reduce renal involvement.