A sample of the drug Nasonex, made by the Schering Corporation, is seen in New York, March 9, 2009. Merck & Co Inc announced it would acquire Schering-Plough Corp for $41 billion, uniting the makers of cholesterol drugs Zetia and Vytorin in the second megadeal for Big Pharma in weeks. REUTERS/Chip East (UNITED STATES BUSINESS HEALTH)