Although they could potentially help prevent severe hyperuricaemia, XOis exert their action by inhibiting the de novo formation of uric acid, thus maintaining the renal toxicity of the xanthine crystals that are formed by inhibiting xanthine oxidase, whereas rasburicase is capable of eliminating the preformed uric acid, avoiding its deleterious effects and preventing the formation of xanthine crystals. Here, XDH is linked to hyperuricemia.