Allopurinol: Uses, Dosage, Side Effects & Brands | MedexInfo

Allopurinol

Rx / Oral

Therapeutic ClassXanthine Oxidase Inhibitor / Antigout

Common Dose100–300 mg daily; up to 800 mg in divided doses

RouteOral

PregnancyCategory C – Use only if clearly needed

Indications ▼

Chronic gout and hyperuricemia

Prevention of uric acid nephrolithiasis (kidney stones)

Management of hyperuricemia associated with malignancy (tumor lysis syndrome)

Mechanism & Pharmacokinetics ▼

Mechanism: Inhibits xanthine oxidase enzyme, reducing conversion of hypoxanthine and xanthine to uric acid, thereby lowering serum and urinary uric acid levels.

Pharmacokinetics: Well absorbed orally; metabolized in liver to oxypurinol (active metabolite). Excreted via kidneys; half-life ~1–2 hours (parent) and ~15 hours (oxypurinol).

Dosage & Administration ▼

Patient Group	Dose / Strength	Frequency
Adults (Gout)	100–300 mg orally	Once daily; may titrate up to 800 mg/day in divided doses
Renal Impairment	Reduce dose based on creatinine clearance	As per guidelines
Tumor Lysis Syndrome	600–800 mg/day in divided doses	Adjust per uric acid levels
Children	Use only if prescribed by pediatrician	Individualized

Side Effects ▼

Rash, pruritus, nausea, diarrhea

Headache, drowsiness

Rare: Stevens-Johnson syndrome, toxic epidermal necrolysis, hepatotoxicity

Gastrointestinal upset (take with food to reduce)

Contraindications ▼

Hypersensitivity to allopurinol

Previous severe cutaneous adverse reactions to allopurinol

Use caution in severe renal or hepatic impairment

Drug Interaction ▼

Azathioprine or mercaptopurine – increased toxicity risk

Warfarin – may alter anticoagulant effect

Theophylline – may increase serum levels

Concomitant renal-toxic drugs – monitor kidney function

Pregnancy & Lactation ▼

Category C – use only if potential benefit outweighs risk

Use caution during breastfeeding; minimal excretion in milk

Clinical / Research Summary ▼

Therapeutic Role: Allopurinol is a xanthine oxidase inhibitor primarily used for the prevention and long-term management of hyperuricemia and gout. It is also used to prevent uric acid nephropathy in patients receiving chemotherapy.

Mechanism-Based Evidence: Allopurinol inhibits xanthine oxidase, reducing the conversion of hypoxanthine and xanthine to uric acid. This lowers serum uric acid levels and prevents urate crystal deposition in joints and tissues.

Clinical Effectiveness: Clinical trials show that allopurinol effectively reduces serum uric acid concentrations, decreases the frequency of gout attacks, and prevents complications such as tophi formation and kidney stones. Dose titration is guided by serum urate levels and renal function.

Safety Profile: Allopurinol is generally well tolerated. Common adverse effects include rash, gastrointestinal discomfort, and transient liver enzyme elevation. Rare but severe hypersensitivity reactions (e.g., allopurinol hypersensitivity syndrome) can occur, especially in patients with renal impairment or certain HLA genotypes.

Research Directions: Ongoing research explores genetic predictors of hypersensitivity, the role of allopurinol in cardiovascular and renal protection, and combination therapies for refractory hyperuricemia.

Patient Counseling Points ▼

Take after meals to reduce gastrointestinal upset

Maintain adequate hydration to prevent kidney stones

Do not discontinue therapy abruptly

Report rash, fever, jaundice, or unusual bleeding immediately

Storage & Handling ▼

Store at 20–25°C, protect from light and moisture

Keep container tightly closed

Keep out of reach of children

Brand Names (Bangladesh & Global) ▼

Bangladesh (Local Brands):

Zyloric Allopurinol Allopur Alpurin

Global / International Brands:

Zyloric Allopurinol Allopurinol

Medical Disclaimer: This clinical summary is for educational purposes only. Always consult a qualified healthcare provider before use.

Reference Hubs:

• Drug Class: Xanthine Oxidase Inhibitors • Conditions: Gout & Hyperuricemia • Pathway: Uric Acid Metabolism