Compared with periprocedural hydration alone,
acetylcysteine with hydration significantly reduces the risk of contrast nephropathy in patients with
chronic renal insufficiency by 50%. For elective contrast procedures,
acetylcysteine should be given in a dose of 600 mg twice daily the day before and on the procedure day. For emergency procedures, a high dose intravenous regimen (150 mg/kg in 500 mL
normal saline over 30 minutes immediately before contrast followed by 50 mg/kg in 500 mL
normal saline over 4h) is effective. Given the low cost and good side-effect profile of
acetylcysteine, it would seem prudent to give this
drug with intravenous fluids to all
critically ill patients scheduled for intravenous or intraarterial contrast procedures.
Theophylline in a dose of 200 mg or 2.5 mg/kg i.v. 30 minutes before contrast may be an effective alternative for emergency procedures. Although its benefit compared with periprocedural hydration alone seems less well established,
theophylline is a particularly attractive option for emergency procedures.