The Effect of Dietary Protein on the Clearance of Allopurinol and Oxypurinol

A decrease in dietary protein is known to depress renal plasma flow and creatinine clearance. Using a randomized crossover design, we investigated the pharmacokinetics of allopurinol and its principal metabolite, oxypurinol, after oral administration of 600 mg of allopurinol in six normal subjects receiving a high-protein (268 g per day) or low-protein (19 g per day) diet. For allopurinol, the area under the curve of plasma concentration versus time increased by a factor of 1.45 (P