PFIZER Inc, the world's biggest drug maker, said yesterday that profit fell 18 percent, missing analysts' estimates, on generic competition to its cholesterol pill Lipitor and blood-pressure drug Norvasc.

Pfizer shares dropped as much as 4.4 percent in early New York trading. First-quarter net income declined to US$2.8 billion, or 41 US cents a share, the New York-based company said yesterday in a statement. Profit, excluding some items, missed analysts' estimates by 5 US cents.

Revenue slid 5 percent to US$11.8 billion. Pfizer has struggled to replace sales lost to generic competition and fired workers to lower costs.

The company doesn't have enough new products in development to replace those going off patent in the next four years, including Lipitor, which accounts for about 40 percent of its profits, analysts said.

"I'm not sure any real progress can happen this year," Linda Bannister, an analyst with Edward Jones & Co in Des Peres, Missouri, told Bloomberg News. "We need to continue to see progression in Pfizer's pipeline, and as it continues to progress, we'll get a sense of how many potential blockbusters there are. I'm not sure that will happen this year."

Pfizer shares fell 89 US cents to US$20.21, at 7:37am in trading before the New York Stock Exchange opened. The stock had fallen 22 percent in the 12 months before yesterday.

A weak United States dollar lifted revenue by US$570 million, or 5 percent, Pfizer said.

Lipitor sales fell 7 percent to US$3.1 billion, including a 4-percent boost from foreign exchange. Doctors have been switching patients from Lipitor, the world's best-selling drug, to generic copies of a rival cholesterol pill, Merck & Co's Zocor.

Sales of Norvasc have plunged 52 percent to US$513 million since generic copies of the blood-pressure medicine came on the market.