Class: Xanthine Oxidase Inhibitor; Antigout
Dosage Forms. Tablet: 100 mg, 300 mg
Common FDA Label Indication, Dosing, and Titration.
1. Gout, mild: 100-300 mg po daily
2. Gout, moderate to severe: 400-600 mg po daily in 2-3 divided doses, max dose 800 mg/d
3. Hyperuricemia, tumor lysis syndrome: Children <6 y, 50 mg po tid; Children 6-10 y, 100 mg po tid; Adults, 600-800 mg/d po daily in 2-3 divided doses; starting 1-3 d prior to chemotherapy
1. Malaria: 12 mg/kg/d po in 3 divided doses × 5 d, with quinine
MOA. Allopurinol decreases the production of uric acid by inhibiting the action of xanthine oxidase, the enzyme that converts hypoxanthine to xanthine and xanthine to uric acid.
Drug Characteristics: Allopurinol
Medication Safety Issues: Allopurinol
Drug Interactions: Allopurinol
Adverse Reactions: Allopurinol
Efficacy Monitoring Parameters. Resolution of clinical signs of gout (pain, stiffness), serum uric acid concentrations measured after 48 h of therapy.
Toxicity Monitoring Parameters. LFTs, renal function, CBC.
Key Patient Counseling Points. Take after meals to lessen gastric irritation. Maintain adequate hydration during therapy. Patient should avoid alcohol or caffeine while taking allopurinol. Seek medical attention if signs and symptoms of myelosuppression, agranulocytosis (severe neutropenia), or Stevens-Johnson syndrome (flu-like symptoms, spreading red rash, or skin/mucous membrane blistering) occur.
Clinical Pearls. Allopurinol for injection is also available, and has been designated an orphan product for use in the treatment of elevated serum or urinary uric acid levels secondary to lymphomas, leukemias, or solid tumors in patients intolerant of oral therapy.