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Complication of treatment-associated tumor lysis of hematologic as well as rapidly proliferating malignancies
May be worsened by thiazide diuretic use
Rapid increase in serum uric acid can cause acute urate nephropathy from uric acid crystallization
To prevent urate nephropathy, serum uric acid must be reduced before chemotherapy
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Acute kidney injury
Hyperuricemia
Hyperphosphatemia (associated symptoms include nausea, vomiting, seizures)
Hyperkalemia (can cause arrhythmias and sudden death)
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Laboratory tests (serum uric acid, phosphorus, calcium, electrolytes [particularly, potassium and sodium], creatinine) should be monitored following initiation of chemotherapy
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Prevention of hyperuricemia, hyperphosphatemia and hyperkalemia are most important, though bicarbonate infusions are no longer recommended
The American Society of Clinical Oncology guidelines recommend aggressive hydration before, during, and after chemotherapy to help keep urine flowing and facilitate excretion of uric acid and phosphorus
Treatment for hyperuricemia
Allopurinol
Blocks the enzyme xanthine oxidase and therefore the formation of uric acid from purine breakdown
100 mg/m2 every 8 hours orally (maximum 800 mg/day) with dose adjustments for impaired kidney function should be given before starting chemotherapy
Rasburicase
Indicated for patients at high risk for developing tumor lysis syndrome or in whom hyperuricemia develops despite treatment with allopurinol
Dosage: 0.1–0.2 mg/kg/day intravenously for 1–7 days
Cannot be given to patients with known glucose 6-phosphate dehydrogenase (G6PD) deficiency nor can it be given to pregnant or lactating women
Elevated potassium or phosphorus levels need to be promptly treated (see Hyperkalemia and Hyperphosphatemia)