Walgreen Co., the largest drugstore operator in the U.S., said Wednesday that its profit jumped 18.8 percent in the fiscal first quarter on a mix of better pricing and generic drug sales.

The Deerfield, Ill., company said its profit rose to $580 million, or 62 cents per share, from $489 million, or 49 cents per share. Its revenue rose 6 percent to $17.34 billion from $16.36 billion. The company's 2011 fiscal first quarter ended Nov. 30.

Analysts surveyed by Thomson Reuters expected a profit of 54 cents per share on revenue of $17.31 billion, on average.

Overall same-store sale sales rose 0.8 percent during the quarter, with front-end same-store sales rising 0.4 percent and pharmacy same-store sales rising 0.9 percent. Same-store revenue is considered a key measurement of retailer health because it excludes results from stores that have been acquired, opened or closed over the last year from the comparison. The revenue figure doesn't include Duane Reade, which was acquired in April.

The company said front-end sales benefited from better promotions and pricing of products, while generic drug sales gave the pharmacy a boost. The company also administered about 5.6 million flu shots through Nov. 30, marking a slight increase from last year's first quarter.

Gross profit margins improved by 80 basis points to 28.5 percent.

Walgreen ran 7,651 stores as of Nov. 30. It has expanded by about 500 stores over the last year, with about half that growth coming after it bought the Duane Reade chain in New York.

In premarket trading, Walgreen shares rose nearly 7 percent to $39.25 from Tuesday's close of $36.83.