Pfizer (PFE) beat the Street on Tuesday, revealing fourth-quarter profits that more than tripled and revenue that surpassed analysts’ forecasts.

The world’s largest drug maker also trimmed its 2012 revenue guidance and unveiled plans to buy back an additional $5 billion of its stock, bringing its total remaining repurchase plans to $9 billion.

New York-based Pfizer said it earned $2.89 billion, or 36 cents a share, last quarter, compared with a profit of $767 million, or 10 cents a share, a year earlier. Excluding one-time items, it earned 47 cents a share, topping estimates by a penny.

Revenue rose 6.2% to $17.56 billion, exceeding the Street’s view of $16.96 billion.

“I am pleased with our solid financial performance again this quarter and this year despite continued challenging market conditions,” CEO Ian Read said in a statement.

Looking ahead, Pfizer said it expects 2012 revenue to range between $63 billion and $65.5 billion, which would come in well shy of consensus calls for $66.80 billion. Pfizer blamed the new guidance on excluding the “projected contribution from future business development transactions.” 

Previously, Pfizer forecasted revenue of $65.2 billion to $67.7 billion.

However, Pfizer said it still sees non-GAAP EPS of $2.25 to $2.35 for 2012, the midpoint of which would meet forecasts from analysts for $2.30.

Pfizer shareholders sent the stock 1.5% higher to $18.50.

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