The U.S. Food and Drug Administration has approved expanded use of Pfizer Inc's blockbuster cholesterol-lowering medicine Lipitor by five new categories, including one to reduce the risk of non-fatal heart attacks and strokes, the company said on Wednesday.

The expanded label for the world's top-selling prescription drug will also now include its approval for use in reducing the risks of certain types of heart surgery, hospitalization for heart failure, and chest pain in patients with heart disease.

Pfizer said Lipitor is the first cholesterol-lowering drug to win approval for reducing risk of hospitalization for heart failure.

The expanded label may provide Pfizer sales representatives with new ammunition in the battle to stem market erosion as health plans turn up the pressure to switch patients to much less expensive generic versions of Merck & Co. Zocor.

Data from the trials of high-dose Lipitor used to gain the label expansion could also help in the face of mounting competition from powerful cholesterol medicines such AstraZenaca's Crestor and Vytorin from Schering-Plough Corp. and Merck.

However Deutsche Bank analyst Barbara Ryan does not believe the new indications will materially alter Lipitor sales, which last year were about $13 billion.

They're holding their own in a difficult climate but I don't think the extended indications are going to change anything, she said. It's nice to have them, but I don't think it will change anything.

Investors appeared to be somewhat more optimistic, sending Pfizer shares up 1 percent.

The expanded approvals were based on a five-year study of 10,000 patients with heart disease and elevated levels of LDL, or bad cholesterol, comparing Lipitor at its lowest and highest doses.

In the study, patients taking the 80 milligram Lipitor had a 22 percent reduction in the risk of major cardiovascular events compared with the typical 10 mg starting dose. There was also a 26 percent reduction in the risk of hospitalization for heart failure in the 80 mg group.

Pfizer shares were up 21 cents to $25.40 mid-day on the New York Stock Exchange.

(Additional reporting by Kim Dixon in Chicago)