Drugmaker Merck & Co. posts a 57 percent drop in first-quarter income due to a fall in both sales of its drugs and income from its partnership on cholesterol medicines.

Schering-Plough Corp., in the process of being acquired by competitor Merck & Co., said Tuesday drug sales fell in the first quarter but profit tripled because of a charge in last year’s quarter related to an acquisition.

Schering-Plough, in the process of being acquired by competitor Merck, says drug sales fell in the first quarter but profit tripled because of a charge in last year’s quarter related to an acquisition.

Merck & Co., a Dow component and the world’s No. 8 drug maker by revenue, reports earnings for the first quarter on Tuesday morning. The following is a summary of key developments and analyst opinion related to the period.

Fears over shaky credit markets are baked into Merck’s $41.1 billion agreement to buy rival drugmaker Schering-Plough.

Wall Street managed an advance Monday after a drugmakers Merck and Schering-Plough announced a $41 billion deal.

NAME: Merck & Co.

Stocks were fluctuating Monday as a $41 billion deal between drugmakers Merck and Schering-Plough did little to jolt investors out of their pessimistic mood.

Stocks are falling as a $41 billion deal between drugmakers Merck and Schering-Plough does little to jolt investors out of their pessimistic mood.

Merck & Co. is buying Schering-Plough Corp. for $41.1 billion in stock and cash in a deal that gives the maker of asthma drug Singulair more firepower to compete in a drug industry facing slumping sales, tough generic competition and intense cost pressure