Rasburicase is a urate oxidase that degrades uric acid to the more soluble allantoin. It is a recombinant protein cloned from Aspergillus flavus. It is useful in patients with the tumor lysis syndrome (TLS) complicated by hyperuricemia.
Risk of TLS
Plasma Uric Acid Concentration
Dose
high
NA
0.20 mg/kg once daily
NA
> 7.5 mg/dL (> 450 µmol/L)
0.20 mg/kg once daily
intermediate
<= 7.5 mg/dL
0.15 mg/kg once daily
low
<= 7.5 mg/dL
0.05 to 0.10 mg/kg once daily
The dose is suspended in 50 mL of normal saline and infused intravenously over 30 minutes.
Duration of therapy depends on the plasma uric acid concentration. The average period is 3 days but may range from 1 to 7 days.
Urine should not be alkalinized with sodium bicarbonate during therapy with rasburicase.
Blood samples for uric acid measurement should be placed on ice immediately. Otherwise rasburicase in the sample may continue to destroy the uric acid, resulting in a lower value. The sample should be tested within 4 hours of collection.
Contraindications:
(1) glucose-6-phosphate dehydrogenase deficiency
(2) anaphylaxis or hypersensitivity reaction to rasburicase or dose component
(3) hemolytic reaction to rasburicase or dose component
(4) methemoglobinemia to rasburicase or dose component
Complications include:
(1) 10% of patients develop anti-rasburicase antibodies
(2) anaphylaxis
(3) methemoglobinemia
(4) hemolytic anemia
(5) fever
(6) neutropenia
(7) respiratory distress
(8) mucositis
(9) nausea and vomiting
(10) headache
(11) diarrhea
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