The company also warned of four factory closings or sales outside the United States and said it could suffer $700 million in lost earnings in 2008 because of scientific questions over the effectiveness of cholesterol drugs Zetia and Vytorin that likely will lead to lower sales of the drugs.

Merck reported net income of $3.3 billion, or $1.52 a share, compared with $1.7 billion, or 78 cents a share, in the year-earlier first quarter. The company employs 12,000 people in the Philadelphia area.

First-quarter sales were $5.82 billion in 2008, compared with $5.77 billion in 2007.

First-quarter restructuring costs were $85 million in 2008, compared with $186 million in the same period in 2007.

The AstraZeneca payment relates to partial retirement of Merck's ownership in a joint venture. With the payment, Merck's ownership stakes in Toprol-XL, Pulmicort, Rhinocort and Symbicort ends, according to an AstraZeneca statement.

Richard T. Clark, chairman, president and chief executive officer, said in a statement that the financial performance "shows that Merck has the right strategy in place to manage through difficult industry dynamics and unexpected challenges."

Global Fosamax sales fell 37 percent to $470 million in the first quarter, the company said. Fosamax is used to treat or prevent postmenopausal osteoporosis.

A looming problem for Merck is Vytorin, which it markets jointly with Schering-Plough Corp. Vytorin is a combination of the drugs Zocor and Zetia.

Sales of Vytorin likely will decline this year after a panel of doctors said March 30 at a meeting of cardiologists in Chicago that the medicine should be used only as a last resort, experts say.

Clark told analysts that the company will close or sell operations in Italy, South Korea, Pakistan and Australia, which will accelerate cost savings and boost margins.

"Merck's strong base business performance has been, and will continue to be, driven by cost cutting via restructuring, and strong sales of new products, namely Gardasil and Januvia," Deutsche Bank AG analyst Barbara Ryan said in a note to clients.

Merck said it anticipated 300 product launches in 2008.

Shares fell 13 cents, to close at $39.63 on the New York Stock Exchange.