Drugstore chain Walgreen's revenue from established stores climb 4.5 percent in November

Strong prescription drug sales, aided by a rise in flu shots, helped to push Walgreen's revenue from established stores up more than 4 percent last month.

The nation's largest drugstore chain said Wednesday that revenue from the pharmacies of stores open at least a year climbed 6.7 percent in November, while sales outside of the pharmacy inched up less than 1 percent.

These figures are seen as a key indicator of a retailer's health because they exclude the potentially distorting impact of recently opened or closed stores. Walgreen Co. had 8,229 stores in operation at the end of the month, or 30 more than a year ago.

Prescriptions filled at established stores grew 2.6 percent in November. Walgreen also has doled out nearly 7 million flu shots so far this season, up from more than 6.1 million last year. That growth helped the company counter a hit last month from a shifting calendar. November had one additional Sunday and one fewer Friday compared with the same month last year.

Weekdays are typically busier for chain drugstores because customers are more inclined to visit a doctor on those days and then stop to fill a prescription. The company said that calendar shift negatively impacted total comparable sales by 1.3 percentage points.

Customer traffic at established Walgreen stores slipped again in November, but those who visited purchased more, continuing recent trends.

Shares rose 55 cents to $67.30 Wednesday before markets opened.