Indoco Remedies has secured US Food & Drug Administration approval to manufacture and sell the generic of Zyloprim tablets, the company said in an exchange filing on Friday. Indoco Remedies will sell the generic allopurinol tablets in 100 mg and 300 mg strengths. Allopurinol is primarily used in the treatment of excess uric acid in blood. Shares of Indoco Remedies were down 4.8 per cent at ₹307.20 on the NSE.