NEW YORK (AP) — Merck & Co. and Schering-Plough Corp. said Thursday they have won merger approval from the Federal Trade Commission and antitrust regulators in Switzerland and Canada. Merck hopes to close its $41.1 billion acquisition of Schering-Plough Corp. before the end of the year. The companies said that the FTC and Canadian Competition Bureau ended their waiting periods to review the transaction. European regulators cleared the deal this month, but it's still under review in China and Mexico. The deal would create the world's second-largest producer of prescription medicines, with about $42 billion in annual sales. That would place it behind only Pfizer Inc., which this month bought Wyeth for $68 billion. Merck and Schering-Plough shareholders approved the sale in August. Shares of Merck fell 74 cents, or 2.3 percent, to close regular trading at $31.31. Schering-Plough shares lost 31 cents to finish at $28.43.