Walgreen Co.'s prescriptions and profits may get a boost from flu season, Medicare drug plans and the health care overhaul, according to a Jefferies analyst who raised his rating on the drugstore chain's shares.

The Deerfield, Ill., company's cost savings from its acquisition of a stake in European health and beauty retailer Alliance Boots have also been faster than expected, said analyst Scott A. Mushkin said in a Monday research note.

He raised his rating on the stock to "Buy" from "Hold" and increased his price target to $47 from $40.

Walgreen spent $4 billion last year to buy a stake in Alliance Boots, a Swiss company that runs the largest drugstore chain in the United Kingdom.

Walgreen is the largest drugstore chain in the U.S., with more than 8,000 stores. It said Friday that prescriptions filled at stores open at least a year fell 2.3 percent in December.

But Mushkin said the company's new, preferred status in some large Medicare prescription drug plans should help reverse that. Medicare is the federal program that provides health coverage for the elderly and disabled people.

The analyst also noted that Walgreen may soon have more favorable comparisons for the monthly prescription figure.

Walgreen didn't fill prescriptions for pharmacy benefits manager Express Scripts Holding Co. for the first eight and a half months of 2012 after the companies failed to agree on a new contract. That pushed down prescription totals and revenue, which will make comparisons in 2013 easier.

Company shares climbed 51 cents to $37.69 Monday before markets opened.