Not recommended in patients w/ ischaemic heart disease or CHF; Lesch-Nyhan syndrome; organ transplant patients. Closely monitor patients for symptoms of allergic/hypersensitivity reactions. Gout flares may occur during treatment initiation. Perform liver function test prior to treatment initiation & periodically thereafter based on clinical judgment. Use w/ caution in patients w/ altered thyroid function. Rare hereditary problems of galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption. Concomitant use w/ mercaptopurine/azathioprine. Severe renal impairment. Moderate to severe hepatic impairment. May impair ability to drive or operate machinery. Should not be used during pregnancy & lactation. Childn <18 yr.