Zyloric Tabs ( ALLOPURINOL 100mg)

Description

Zyloric Tablets contain Allopurinol 100mg, a xanthine oxidase inhibitor used as the cornerstone pharmacological agent for the long-term management of hyperuricemia and gout, working by competitively inhibiting the enzyme xanthine oxidase — which catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid — thereby reducing the synthesis of uric acid, lowering serum and urinary urate levels, preventing the deposition of monosodium urate crystals in joints, soft tissues, and kidneys, and facilitating the gradual dissolution of existing tophi over time with prolonged therapy. Unlike uricosuric agents that increase renal excretion of uric acid, Allopurinol reduces uric acid production at its source, making it particularly suitable for overproducers of uric acid, patients with renal impairment, uric acid nephrolithiasis, and those in whom uricosuric drugs are contraindicated or ineffective, and its active metabolite oxypurinol (alloxanthine) also contributes significantly to xanthine oxidase inhibition with a longer half-life of 18–30 hours supporting once-daily dosing. It is indicated for the long-term prevention of gouty arthritis and tophaceous gout, hyperuricemia associated with malignancy and cytotoxic chemotherapy (tumor lysis syndrome prophylaxis), recurrent uric acid and calcium oxalate renal calculi, and hyperuricemia associated with enzyme disorders such as Lesch-Nyhan syndrome, with the usual starting dose of 100mg once daily gradually titrated upward to 200–300mg daily for mild gout and 400–600mg daily for moderate-to-severe tophaceous gout based on serum uric acid response. Zyloric should never be initiated during an acute gout attack as it may paradoxically prolong or precipitate attacks by mobilizing urate deposits; it must always be started with colchicine or NSAID prophylaxis for the first 3–6 months, and the most serious adverse effect is the rare but potentially fatal allopurinol hypersensitivity syndrome (AHS) characterized by severe cutaneous reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis, occurring more frequently in patients carrying the HLA-B*5801 allele (common in Han Chinese, Korean, and Thai populations) and those with renal impairment.