Razi Journal of Medical Sciences

    Background: Tumor Lysis Syndrome (TLS) is the release of intracellular material into blood stream by itself or due to anticancer cytolytic therapies. Hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcemia are the main metabolic disorders of TLS. In order to treat and prevent hyperuricemia in TLS, we used Allopurinol and a new drug- Rasburicase. The aim of this study was to compare the efficacy and safety of these two drugs in the treatment of hyperuricemia (due to TLS) in children with leukemia or lymphoma and also to evaluate the amount and rate of decrease in serum uric acid along with the complications associated with the use of these drugs.  

Methods: In this retrospective-cohort study, children with leukemia and lymphoma whom were admitted in the Hematology and Oncology ward of

Hazrat-e-Ali

Asghar

Childrens

Hospital from 2005 to 2008 were evaluated. They were divided according to the initial uric acid level into treatment group (uric acid ≥ 6.5 mg/dl) and prophylaxis group (uric acid < 6.5 mg/dl). Drug efficacy was determined measuring uric acid 24, 48 and 72 hours after drug administration. The trend of uric acid decline and side effects of the two drugs were determined. According to data Chi² and t-test were used for analysis by the SPSS V.13.

Results: From the total 184 patients with leukemia (69%) and lymphoma (31%), 60.8% were males and 39.2% were females. Mean age was 7.93± 4.247 (1-21) years. Rasburicase was administered in 20 patients and Allopurinol in 164. Also 60.8% were in the treatment group and 39.2% in prophylaxis. Mean leukocyte count was 101910 cells/µl in Rasburicase and 45609.76 cells/µl  in Allopurinol showing significant statistical difference between the two groups (p=0.000). Most of the response to drug was seen in the first 24 hours after drug administration.  First day serum calcium level and hypocalcemia (sign of increased phosphorous level) demonstrated significant statistical difference between the groups (p=0.000). Mean duration of receiving Rasburicase and Allopurinol was 2 days and 6(5.87) days, respectively (p=0.000, T=6.168). Based on the t-test, rate of decrease in the calcium level demonstrated significant statistical difference in both the groups receiving  Rasburicase and Allopurinol (p = 0.144, T=1/467). Mean of uric acid level decline in patients receiving Rasburicase  was from 7.4 to 3.4 mg/dl and for Allopurinol it was from 5.4 to 3.9 mg/dl. Adverse effects were seen in 13 of 184 patients (Rasburicase = 1.6%, Allopurinol = 5.4%).

Conclusion: In conclusion, Rasburicase has high efficacy in treatment and prophylaxis of hyperuricemia in patients with hematologic malignancies. Since it is an expensive medication and not available to all, it was used in 20 patients only. Treatment duration was short in case of Rasburicase (2 days) and the patient becomes ready for chemotherapy in a short duration. Meanwhile Allopurinol which is used frequently by the physicians,  has great efficacy and safety as well and can be  prescribed until the wide distribution of Rasburicase.