Used primarily in the management of tumor lysis syndrome, especially in patients undergoing chemotherapy for hematologic malignancies. It helps prevent the accumulation of uric acid by inhibiting xanthine oxidase, the enzyme responsible for converting xanthine to uric acid. This reduces the risk of acute kidney injury caused by uric acid crystal formation in the renal tubules. Allopurinol sodium is preferred in certain clinical settings where rapid onset is needed and oral administration is not feasible, providing a parenteral option for urate lowering in high-risk patients.