Allopurinol

Administration

• Type: xanthine oxidase inhibitor
• Dosage Forms: tablet, powder for injection
• Routes of Administration: IV, PO
• Common Trade Names: Zyloprim, Aloprim

Adult Dosing

• Gout, nephrolithiasis: 100-300mg PO 1-2 times daily
• Tumor lysis syndrome/hyperuricemia in liquid malignancies: 200-800 mg PO or IV daily

Pediatric Dosing

• <6yo: 150 mg PO daily for 2 to 3 days, then adjust dose for maintenance
• >6yo: 300 mg PO daily for 2 to 3 days, then adjust dose for maintenance
• 200 mg/m(2)/day IV

Special Populations

• Pregnancy Rating: C
• Lactation risk: Infant risk minimal

Renal Dosing

• CrCl 10-20: 200 mg PO or IV daily
• CrCl 3-10: max daily dose 100 mg PO or IV
• CrCl <3: 100mg PO or IV at "extended intervals"

Hepatic Dosing

• No adjustment

Contraindications

• Allergy to class/drug
• Concomitant use with didanosine

Adverse Reactions

Serious

• Cardiac arrest, ventricular fibrillation, heart failure
• SJS/TEN
• Agranulocytosis, myelosuppression, aplastic anemia, thrombocytopenia, eosinophilia
• DIC
• Renal failure
• Respiratory distress
• Hepatotoxicity, granulomatous hepatitis
• Stroke, seizure

Common

• Nausea, vomiting
• Rash, pruritus

Pharmacology

• Half-life: 1-2 hours
• Metabolism: Hepatic
• Excretion: Renal

Mechanism of Action

• Inhibits xanthine oxidase (converts hypoxanthine/xanthine to uric acid), leading to decreased uric acid concentration

See Also

• Gout
• Tumor lysis syndrome