The largest U.S. drugmaker also trimmed its full-year guidance. The company said it now expects full-year earnings, excluding items, of $2.14 to $2.24 a share, down from its previous forecast of $2.20 to $2.30, on revenue of $55.3 billion to $57.3 billion.
It noted that the falling Japanese yen was hurting company sales in that important market.
After the earnings announcement, the company's shares fell in pre-market trading. (Click here to track the company's stock following the report.)
The drugmaker said net income rose 53 percent to $2.75 billion, or 38 cents per share, down from $1.79 billion, or 28 cents per share, a year earlier. Pfizer benefited from a one-time gain compared with a quarter last year that was weighed down by legal and other charges.
Excluding one-time items, the company posted first-quarter earnings of 54 cents per share, down from 58 cents a share in the year-earlier period.
Revenue dropped to $13.5 billion from $14.89 billion a year ago, hurt by wholesaler purchasing patterns that led to lower demand for its Prevnar vaccines against pneumococcal bacteria.
Analysts had expected Pfizer to report earnings excluding items of 55 cents a share on $13.99 billion in revenue, according to a consensus estimate from Thomson Reuters.
—Reuters contributed to this report.