Allopurinol Pharmacology Summary



Xanthine oxidase inhibitor blocking the formation of new uric acid

Initiate 1-2 days prior to chemotherapy

Dosing: 100 mg/m2/dose every 8 hours (max 800mg/day)

 • Usual: 300 mg/day

 • Dose adjustments for CrCl <10mL/min

Side effects: gastrointestinal irritation, rash, fever, hypersensitivity

Drug interactions: 6-mercaptopurine and azathioprine

Limitations:

 • Slow onset of action of 24-72 hours

 • No effect on excretion of pre-formed uric acid

 • Precipitation of xanthine metabolites in the kidney



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