Allopurinol is used to prevent which oncologic emergency?

• A. Hypercalcemia
• B. Tumor lysis syndrome
• C. Anemia
• D. Infections

Answer: (B)

Allopurinol prevents tumor lysis syndrome by lowering uric acid production. It inhibits xanthine oxidase, blocking the conversion of purines to uric acid. When rapidly proliferating tumors are treated, massive cell death releases nucleic acids that become uric acid, which can crystallize in the kidneys and cause acute kidney injury. By reducing uric acid formation, allopurinol decreases the risk of uric acid nephropathy during cancer therapy. Other issues like high calcium, anemia, or infections are not addressed by this mechanism, since they result from different processes, whereas tumor lysis syndrome centers on uric acid buildup and electrolyte disturbances that require additional management.