Dosing Allopurinol in a Patient at Risk for the Tumor Lysis Syndrome

 

Contraindication: history of anaphylaxis, hypersensitivity reaction or allergy to allopurinol

 

Timing: Therapy is started 12-24 hours prior to start of the induction chemotherapy. It is continued during the therapy while ongoing tumor lysis is occurring. It is discontinued after therapy has stopped and once the serum uric acid level has returned to normal.

 

Allopurinol does not increase the excretion of uric acid in hyperuricemia. Rasburicase is used to increase uric acid excretion once formed.

Parameter	Pediatric Oral	Adult Oral	Adult Intravenous
maximum daily dose	300 mg	800 mg	600 mg
mg per square meter per day	150 - 300 mg	300 mg	200-400 mg
mg per kg per day		10 mg
dosing interval	q8h	q8h	q8h, q12h or q24h

 

where:

• When the transition from pediatric to adult dosing occurs is not given. An older adolescent may tolerate adult dosing.

 

Allopurinol dosage reduction for renal failure: >=50%

 

Azathioprine or 6-mercaptopurine dosage reduction if taking allopurinol: 65-75%

 

Drugs which may interact with allopurinol:

(1) dicumarol (coumadin)

(2) thiazide diuretic

(3) chlorpropamide

(4) cyclosporine