<s>[INST] context: Fenoldopam The administration of radiocontrast media can lead to a usually reversible form of acute kidney injury (formerly called acute renal failure) that begins soon after the contrast is administered. In most cases, there are no permanent sequelae, but there is some evidence that its development is associated with adverse outcomes. Prevention There is no specific treatment once contrast-induced acute renal failure develops, and management must be as ,for any cause of acute tubular necrosis, with the focus on maintaining fluid and electrolyte balance. The best treatment of contrast-induced renal failure is prevention. A variety of preventive measures may reduce the risk of contras nephropathv. Types of radiocontrast agents Iodinated radiocontrast agents are either ionic or nonionic and, at the concentrations required for aeriography or computed tomography, are of variable osmolality: First generation agents are ionic monomers; they are highly hyperosmolal (approximately 1400 to 1800 mosmol/kg) compared with the osmolality of plasma. Second generation agents, such as iohexol, are nonionic monomers with a lower osmolality than the first generation radiocontrast media. - The newest nonionic contrast agents are isoosmolal. These isoosmolal agents have a lower osmolality than "low osniolal" second generation drugs. The iso-osnzolal nonionic contrast agent iodixanol appears to reduce the risk of contrast nephropathy in high-risk patients, such as diabetic patients with renal insufficiency, compared to the low osmolal nonionic agent iohexol, but not when compared to other low osnzolal nonionic agents. -However, additional randomized prospective trials comparing iodixanol (or other iso-osmolal agents if developed) to other low osmolal ionic or nonionic agents are required before it can be determined that isoosmolal contrast agents are uniformly less nephrotoxic than low osmolal agents as a class, especially given the substantially greater expense of the only currently available iso-osmolal nonionic agent, iodixanol. Hydration, mantilla, and diuretics Hydration is beneficial, and the type of hydration solution may be impoant. In comparison, the role of diuretics, mannitol and other renal vasodilators in this setting is unceain. Diuretics Several small trials have investigated the effect of diuretics. In one trial, 78 patients with stable chronic renal failure (mean plasma creatinine concentration 2.1 ing/dL or >25 percent, measured 2 to 5 days after the procedure) occurred less frequently among patients who received iloprost compared to placebo (8 versus 22 percent respectively). - Severe hypotension required withdrawal of Iloprost in three patients. Although Iloprost may be effective in the prevention of contrast nephropathy, confirmation of these results in larger definitive trials is necessary before its use can be recommended. Fetzoldopanz - A prospective randomized trial (CONTRAST) assessed the effectiveness of fenoldopam in 315 patients (one-half diabetic) undergoing a cardiovascular procedure who had chronic renal .failure with an estimated creatinine clearance below 60 mllmin (mean 29 m1/min with a mean serum creatinine of 1.8 mg/dL ). - All patients also received one-half normal saline as mentioned above, and contrast nephropathy was defined as an increase in serum creatinine of ?..25 percent above baseline in the first four days. - There was no reduction in the incidence of contrast nephropathy in the fenoldopam group (34 versus 30 percent with placebo). It has been proposed that direct intrarenal administration may be more beneficial. Endothelia: receptor antagonist - A nonselective endothelin receptor antagonist was tested in a multicenter, double-blind randomized trial of high-risk patients undergoing coronary angiography. Compared with those assigned to placebo, a significantly higher percentage of patients who received active therapy sustained contrast nephropathy (56 versus 29 percent); this observation raises the possibility that endothelin may actually provide an intrinsic protective effect rather than contributing to the development of acute renal failure. Alternatively, selective endothelin receptor antagonists may be required to demonstrate prophylactic value in this setting. Summary And Recommendations Optimal therapy to prevent contrast-induced acute renal failure remains unceain. Patients with near-normal renal function are at little risk and,few precautions are necessary other than avoidance of volume depletion. We recommend the following preventive measures for patients at increased risk of contrast nephropathy, which is defined a serum creatinine 1.5 mg/d1. (132 tnicromol/L) or an estimated glomerular filtration rate <60 ml/1.73 m2, Use, if -possible, ultrasonography, MRI without gadolinium contrast, or CT scanning without radiocontrast agents. We recommend NOT using high osmolul agents. We recommend the use of iodixanol or nonionic low osmolal agents such as iopamidol or ioversol rather than iohexol. Use lower doses of contrast and avoid repetitive, closely spaced studies. Avoid volume depletion and nonsteroidal anti-inflammatory drugs. If there are no contraindications to volume expansion, we recommend isotonic intravenous fluids prior to and continued for several hours after contrast administration. The optimal type of fluid and timing of administration are not well established. We suggest isotonic bicarbonate rather than isotonic saline. Despite conflicting data, we suggest that acetylcysteine be administered the day before and the day of the procedure, based upon its potential .for benefit and low toxicity and cost. If acetylcysteine is administered, we suggest giving 1200 mg orally twice daily rather than 600 mg twice daily the day before and the day of the procedure. Based upon the lack of convincing evidence of benefit and the potential risk of anaphylactoid reactions, we suggest not using intravenous acetylcysteine for the prevention of contrast nephropathy. (Note: Oral acetylcysteine is used.) We recommend NOT using mannitol or other diuretics prophylactically. Among patients with stage 3 and 4 CKD, we recommend NOT performing prophylactic hemofiltration or hemodialysis after contrast exposure. Among patients with stage 5 CKD, we suggest prophylactic hemodialysis after contrast exposure if there is already a .functioning hemodialysis access. [/INST] question: Which drug is not used to prevent contrastnephropathy aEUR' | options: A: Fenoldopam B: N-acetylcysteine C: Infusion of Hair normal saline D: Hemodialysis | answer: A </s>