Letter by Kielstein et al Regarding Article, “High-Dose Allopurinol Improves Endothelial Function by Profoundly Reducing Vascular Oxidative Stress and Not by Lowering Uric Acid”

To the Editor: We read with interest the paper by George and colleagues1 about the benefit of high-dose allopurinol on endothelial dysfunction in patients with class II or III heart failure. The authors suggest that on the basis of the steep dose–response relationship between allopurinol and endothelial function, a dose of 600 mg/d yields the most improvement in endothelial function. We are concerned about the implications of …