Drugmaker Pfizer Inc. on Tuesday reported a huge jump in its first-quarter revenue, thanks to its giant acquisition of Wyeth last October, but charges from the deal weighed down net income.

The maker of cholesterol fighter Lipitor and impotence pill Viagra earned $2.03 billion, or 25 cents per share, in the latest quarter, down 26 percent from $2.73 billion, or 40 cents per share.

Adjusted income for the first three months totaled $4.88 billion, or 60 cents per share, rising 33 percent from $3.67 billion, or 54 cents a share, a year earlier.

With the addition of Wyeth blockbusters such as antidepressant Effexor and children's vaccine Prevnar, Pfizer's revenue reached $16.75 million. That's up 54 percent from $10.87 billion a year earlier.

Analysts polled by Thomson Reuters, on average, were expecting slightly lower earnings per share of 53 cents and revenue of $16.58 billion.

Pfizer said sales of Wyeth products increased revenue by $5.3 billion, or 48 percent, while the effects of favorable currency exchange rates boosted revenue another $733 million, or 7 percent.

"Our results this quarter demonstrate the ability of our colleagues to deliver solid operational performance in a challenging environment as well as extract value for shareholders from the acquisition of Wyeth," Pfizer Chief Executive Jeff Kindler said in a statement.

The company said the U.S. health care overhaul reduced revenue in the first quarter by $56 million.

Chief Financial Officer Frank D'Amelio said Pfizer now expects the new health law to reduce revenue by about $300 million this year, but the company is reaffirming its profit forecast for this year anyway. Pfizer is forecasting earnings per share of 95 cents to $1.10 per share, adjusted income of $2.10 to $2.20 per share, and revenue of about $68 billion.

In premarket trading, Pfizer shares edged up to $17.17 from Monday's close of $16.91.