- Discussion:
    - for established gout (Not acute Gout), hyperuricemia of malignancy (or increased cell turnover);
    - is useful for established gout with urolithiasis (both for uric acid stones and calcium oxalate stones);
    - adult: Initially 100mg PO qd;
    - increase by 100mg at weekly intervals until serum uric acid of < 6mg/dl is attained or a total dose of 800 mg/day is attained;
    - maintenance dose with mild gout: 300mg PO qd;
    - severe gout try 400-600 mg/day in divided doses;
    - prophylactic dose of colchicine (0.5mg bid) is recomended by some to prevent an increase in attacks of gout when allopurinal is started;
    - secondary hyperuricemia associated with therapy of malignancies:
    - 600-800mg/day in divided doses for 3 days;
    - must reduce dose in patients with renal insufficiency and in patients receiving mercaptopurine or azathioprine;
    - allopurinol should be used carefully with those w/ renal insufficiency, a h/o uric acid stones and those with a 24 hour urinary acid 
            excretion over 1,100 mg;
    - peds: Use only for treating Hyperuricemia of malignancy in children:
          - 10mg/kg/24hrs divided q8hr
          - (max 600 mg/24 hr period); or 6-10 yrs: 100mg PO tid;

- Allopurinol Interactions and Toxicities:
    - interaction w/ coumadin (prolonged PT)
    - thiazide diruretics (increased allopurinol toxicity)
    - chlorpropamide (increased hypoglycemia)
    - cyclophosphamide and other cytotoxic agents (bone marrow suppression);
    - hypersensitivity
           - rash develops in approximately 2 % of patients treated with allopurinol;
           - rash is much more common when taking ampicillin/amoxicillin;
           - these rashes are managed with lower dosage or discontinuation of medication;
    - allopurinol hypersensitivity syndrome:
           - occurs in 1/1000 patients treated with allopurinol and is more common in patients taking allopurinol;
           - characterized by fever, exfoliative dermatitis, eosinophilia, leukocytosis, impaired renal function, hepatocellular injury;
           - these reactions are severe and may be fatal;
           - these are generally managed with prednisone

The role of oxygen-derived free radicals in the management of venous (varicose) ulceration: a new approach.

Xanthine oxidase-derived oxygen radicals induce pulmonary edema via direct endothelial cell injury.

Relation between adverse events associated with allopurinol and renal function in patients with gout.

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Wednesday, December 14, 2011 3:00 pm