Merck & Co. Inc. said yesterday that fourth-quarter profit rose 5.5 percent because sales of its five key prescription drugs jumped 20 percent.

Merck, the second-largest U.S. drugmaker, reported earnings of $1.86 billion, or 81 cents a share, up from $1.76 billion, or 75 cents a share, a year ago.

Total sales in the fourth quarter rose 10 percent, to $12.6 billion, with its Zocor cholesterol medicine accounting for $2.1 billion in sales. The 81 cents per share matched the forecast of analysts surveyed by Thomson Financial/First Call.

Merck officials repeated yesterday that they expected earnings to be flat in 2002, compared with 2001, because of patent expirations on several medications and a dip in sales of its Vioxx arthritis pain reliever. Vioxx has been the subject of several lawsuits that allege patients may face increased risk of heart attack or gastrointestinal bleeding.

Sales of Vioxx fell to $550 million in the fourth quarter from $795 million in the third quarter.

"Merck's potential for growth is pretty good," said analyst Bob Kirby at Edward Jones in St. Louis. "It's just going to be ugly in 2002. But after a year, the big loss will be over, and you will be left with key growth drivers," including several new medicines in the research pipeline.

Merck, based in Whitehouse Station, N.J., was hurt by patent expirations last year on heartburn treatment Pepcid and hypertension medicine Vasotec, which are losing sales to cheaper generic versions. Two other Merck drugs could come off patent this year - hypertension drug Prinivil and ulcer medicine Prilosec.

Merck's prescription-drug sales have been driven by five medicines: cholesterol-lowering Zocor, blood pressure drugs Cozaar and Hyzaar, osteoporosis treatment Fosamax, asthma drug Singulair, and Vioxx.

A component of the Dow Jones industrial average, Merck shares rose $1.29 yesterday to $59.29. Merck employs 10,000 people at its West Point campus and two other locations in Montgomery County.

---

Linda Loyd's e-mail address is lloyd@phillynews.com.