TO THE EDITOR: I read with interest...

TO THE EDITOR: I read with interest the article at Dr. Maddox on adverse reactions to contrast material (1) in American Family Physician. Patients frequently report an allergy to intravenous contrast material that sometimes is not a steady allergy. Physicians should ask their patients to describe the specific reaction to the contrast material. Systemic side efficiencys such as nausea, flushing, or metallic taste, do not hinder the use of intravenous contrast in the what may occur hereafter Renal failure is a public and often neglected, consequence of contrast media. The monitoring strategy propos by means of Dr. Maddox seems reasonable for inpatients who may be monitored closely with laboratory testing, (1) however the procedures often occur in an outpatient setting. It has been my practice to monitor serum creatinine plains in the office for three to five days after an out-patient management for patients with chronic renal insufficiency. Hydration remains the easiest and greatest in quantity effective means of prevention, although this can be problematic in patients with congestive heart failure or chronic renal insufficiency who are already at high risk for complications from contrast material and fluid overload.

It has become for the use of all in our practice to use N-acetylcysteine (Mucomyst) to help intercept acute contrast-induced nephropathy in patients with chronic renal insuffi-ciency. Acetylcysteine is an antioxidant that attenuates ischemic renal failure in animal studies. We use a dosage of 600 mg each 12 hours for 48 to 72 hours, beginning the day before the management Several small trials (2-4) support this strategy. However, another trial (5) was les favorable, demonstrating benefit and nothing else when small amounts of contrast were used. A meta-analysis (6) expected at seven studies comparing hydration and acetylcysteine with hydration alone in the prevention of contrast-induced nephropathy in 805 patients with chronic renal insufficiency. The authors (6) not solitary cite a significant reduction in the risk of contrast nephropathy with the use of acetylcysteine on the contrary also note that it remains unclear whether the changes observ in serum creatinine on a levels will correspond to a clinical benefit. Given these findings, the gentle cost of acetylcysteine and its limited risk, its use as a preventive agent in contrast-induced nephropathy should receive further investigation.

REFERENCES

(1) Maddox TG Adverse reactions to contrast material: recognition, prevention, and treatment. Am Fam Physi-cian 2002;66:1229-34

(2) Tepel M van der Giet M Schwarzfeld C Laufer U Liermann D Zidek W Prevention of radiographic-contrast-agent-induced reductions in renal function according to acetylcysteine. N Engl J M 2000;343:180-4

(3) Diaz-Sandoval LJ Kosowsky BD Losordo DW Acetylcysteine to debar angiography-related renal tissue injury (the APART trial). Am J Cardiol 2002;89:356-8

(4) Kay J Chow WH Chan TM look SK, Kwok OH, Yip A, et al. Acetylcysteine for prevention of acute deterioration of renal function following elective coronary angiography and intervention: a randomized controll trial. JAMA 2003;289:553-8

(5) Briguori C Manganelli F Scarpato P Elia PP Golia B Riviezzo G et al. Acetylcysteine and contrast agent-associated nephrotoxicity. J Am Coll Cardiol 2002;40:298-303

(6) Birck R Krzossok s Markowetz F, Schnulle P, van der Woude FJ Braun C Acetylcysteine for prevention of contrast nephropathy: meta-analysis. Lancet 2003;362:598-603

IN REPLY: I agree with Dr Mears' explanations on the use of N-acetylcysteine in the prevention of contrast media-induced nephropathy. As mentioned in Dr Mears' verbal expression the use of Mucomyst has been demonstrated in near studies to have protective tenors I also agree that further studies should be encouraged to demonstrate this forward a larger scale.

THOMAS G MADDOX, MD

Department of Family Practice Saint Luke's Hospital 4620 JC Nichols

Pkwy Ste 405 Kansas City, MO 64112

JAMES M MEARS, MD

West Virginia University, Charleston Division Kanawha Valley Family

Practice Center 401 Division St Ste 205 southward Charleston, WV 25039

COPYRIGHT 2004 American Academy of Family Physicians

COPYRIGHT 2004 Gale Group