The world's biggest drugmaker said it had earned $2.89 billion, or 36 cents per share, in the fourth quarter, compared with $767 million, or 10 cents per share, a year earlier.
Excluding special items, Pfizer earned 47 cents per share, beating the analysts' average forecast of 46 cents.
Quarterly revenue rose 6 percent to $17.56 billion, topping Wall Street expectations of $16.96 billion. It would have risen 7 percent if not for negative foreign exchange factors.
Global sales of prescription drugs rose 3 percent to $15.1 billion. Revenue in emerging markets, where the company is pinning its hopes for earnings growth, rose 25 percent to $2.37 billion, a marked improvement from flat sales in the third quarter.
Pfizer said it still expected 2012 earnings, excluding special items, of $2.25 to $2.35 per share. But the company said it now expected revenue that year of $63 billion to $65.5 billion, compared with its earlier view of $65.2 billion to $67.7 billion.
Moreover, Pfizer said its preserved 2012 earnings forecast hinged in part on a cut in its research and development spending, to between $6.5 billion and $7 billion, from its previous target of $8 billion to $8.5 billion.
Driving this decline is the planned reduction in the number of disease areas the company will focus on, Pfizer said in a release. The company noted it would leave its research site in Sandwich, England, but enhance its operations in Cambridge, Massachusetts.
Shares of Pfizer were up 1.8 percent at $18.55 in premarket trading.
(Reporting by Ransdell Pierson; Editing by Lisa Von Ahn)