Clinical Overview
Allopurinol Tablets (100mg) is a purine analogue xanthine oxidase inhibitor on the WHO Model List of Essential Medicines. It and its active long-lived metabolite oxypurinol act as substrate analogues for xanthine oxidase, competitively and non-competitively inhibiting the enzymatic oxidation of hypoxanthine to xanthine, and xanthine to uric acid. This profoundly reduces serum and urinary uric acid levels, halts monosodium urate crystal precipitation, dissolves existing tophi, and prevents recurrent gouty attacks. Indicated for long-term management of hyperuricemia in gout, recurrent calcium oxalate/uric acid nephrolithiasis, and prevention of tumor lysis syndrome during cancer chemotherapy.
Active Pharmaceutical Ingredients
Verified Clinical References
Usage Guidelines
Take orally 100 mg to 300 mg once daily immediately after meals with a full glass of water. Titrate upward every 2 to 4 weeks until serum uric acid drops below the target of <6.0 mg/dL (or <5.0 mg/dL in severe tophaceous gout). Maintain vigorous hydration (at least 2 to 3 liters of fluid daily). MANDATORY: Co-administer prophylactic colchicine (0.5 mg daily) or an NSAID during the first 3 to 6 months to prevent paradoxical gout flare-ups.
General Administration Advice: Adhere strictly to the prescribed dosage, frequency, and treatment course. For oral medications, swallow with sufficient water. Never stop antibiotics, psychiatric medications, or antihypertensives abruptly without clinical direction.
Possible Side Effects
Common: Maculopapular rash, diarrhea, nausea, asymptomatic transaminase elevations, initial gout flare-ups. Rare/Severe: Allopurinol Hypersensitivity Syndrome (AHS: life-threatening triad of rash/TEN, eosinophilia, systemic vasculitis, hepatitis, and acute renal failure), and Stevens-Johnson syndrome.
*Note: Individual physiological responses vary. While many patients experience few or no side effects, notify your treating physician if adverse reactions persist or if hypersensitivity (angioedema, skin rash, dyspnea) occurs.
Precautions & Warnings
Black Box Warning: Discontinue IMMEDIATELY at the earliest sign of skin rash, hives, or fever (rash may herald fatal Allopurinol Hypersensitivity Syndrome). Screening for the HLA-B*58:01 allele is strongly recommended in patients of Asian descent (very high risk of SJS/TEN). Do NOT initiate during an acute gout attack; wait until the acute flare has resolved. Reduce dose in renal impairment. MAJOR DRUG INTERACTION: Co-administration with azathioprine or 6-MP causes fatal bone marrow aplasia (reduce azathioprine dose by 75%).
Schedule H (Prescription Required)
This medication is scheduled under statutory drug regulatory frameworks (CDSCO / Drugs & Cosmetics Rules). Dispensing requires a valid medical prescription from a registered medical practitioner. Self-medication or unsupervised dosage adjustment carries significant clinical risks.
Medical Disclaimer: Statutory Clinical Disclaimer: The information provided is for educational and price-transparency purposes only and does not constitute medical advice, clinical diagnosis, or analgesic treatment guidance. Always consult a registered physician or orthopedic specialist before taking pain relievers, anti-inflammatory medications, or anti-arthritic therapies.