The Effectiveness of the Xanthine Oxidase Inhibitor Allopurinol in the Treatment of Gout

Abstract

A xanthine oxidase inhibitor, allopurinol, was administered to 8 patients with gout, 1 patient with xanthinuria and 3 normal volunteer subjects. It was well tolerated by 11 of 12 subjects and was effective in markedly decreasing the plasma uric acid concentration and urinary uric acid excretion. Balance studies showed that the oxypurines xanthine and hypoxanthine largely replaced the deficit in uric acid excretion in both normal and gouty subjects. The renal clearance of oxypyrines was shown to be much greater than that of uric acid. The inhibition of xanthine oxidase is advantageous since the more rapid renal clearance of oxypurines results in low plasma oxypurine concentrations which do not exceed saturation and therefore tissue deposits would be unlikely. Allopurinol may be used in conjunction with uricosuric drugs to obtain maximal total purine excretion and to allow unloading of large urate deposits. It also has a potential use in patients with hyperuricemia and renal insufficiency who are refractory to uricosuric therapy or in gout patients who cannot tolerate any of the other drugs used to lower plasma ruate concentrations.