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 #Allopurinol #Pharmacology #pathophysiology #gout #uricacid
