Allopurinolis a xanthine oxidase inhibitorand is themainstay in thetreatment of hyperuricemia. The incidence of drug hypersensitivity reaction with allopurinol is 2%.When a drug hypersensitivity reactionoccurs, the best course of action for such patients is to discontinue the culpritdrug and to pass on alternative drugs. However, in cases where there is no alternative treatment or the effectiveness of alternative treatment is significantly lower, desensitization protocols can be used. Slow and rapid desensitization protocols are available in the literature for allopurinol. However, the duration of these protocols is quite variable. We present two pediatric patients with chronic renal failure who had a delayedtype hypersensitivity reaction with allopurinol. Since this treatment is very necessary and there is no alternative drug, desensitization is planned and slow weekly allopurinol desensitization has been successfully applied.
