Helped by business from the recently acquired Duane Reade stores, Walgreen Co. reported a healthy sales increase for April, although same-store sales dipped in the month.

Walgreens also said that overall revenue and comparable-store sales for the March/April Easter selling period were up versus a year ago.

The Duane Reade outlets weren't included in the same-store results, Walgreens noted.

DEERFIELD, Ill. — Helped by the recently acquired Duane Reade stores, Walgreen Co. reported a healthy sales increase for April, although same-store sales dipped in the month.

The drug store chain said Wednesday that April sales totaled $5.68 billion, up 5.9% from $5.36 billion a year earlier. The Duane Reade acquisition, which closed April 9, contributed 2.2 percentage points to the revenue increase, according to Walgreens. Sales rose 6% in the pharmacy and 4.9% in the front end in April.

Sales in comparable stores for April — which doesn’t include any Duane Reade stores —  decreased 0.2% year over year, down from a 2.3% gain in March and a 0.4% uptick in February.

Walgreens said April comparable-store sales reflect a 0.7 percentage point negative impact from this year’s earlier Easter, which pulled seasonal sales into March, but got a 0.2 percentage point lift from calendar day shifts.

In the pharmacy, same-store sales edged up 1.1% during April. The increase includes a 0.3 percentage point positive impact from calendar day shifts plus negative impacts of 1.6 percentage points due to generic drug introductions and 0.7 percentage point due to lower incidence of flu, Walgreens noted.

Prescriptions filled at comparable stores were up 2.6% in April, including 1.4 percentage points from more patients filling 90-day prescriptions. The drug retailer said calendar day shifts positively impacted prescriptions filled in comparable stores by 0.3 percentage point, while the lower incidence of flu negatively impacted prescriptions filled by 1.4 percentage points.

Comparable-store sales in the front end declined 2.6% in April, reflecting a 2.1 percentage point negative impact from the earlier Easter.

For the seasonal March/April selling period, same-store sales rose 1%, while overall revenue grew 6.1%, Walgreens said. In the front end, comparable-store sales decreased 0.2% during the two months. Front-end sales are cycling the cigarette tax increase implemented in March 2009 and negatively impacted March/April comparable-store sales in the front of the store by 1 percentage point versus the incoming trend, the retailer noted.

Meanwhile, revenue for the calendar year to date came in at $22.14 billion, up 4.5% from $21.19 billion a year ago. Fiscal 2010 year-to-date sales, covering an eight-month period, were $44.84 billion, up 6.1% from $42.25 billion a year earlier.

Walgreens said it opened 25 stores in April, including four relocations, and acquired 262 sotes — including 258 Duane Reade drug stores — and closed one store.

As of April 30, Walgreens operated 7,507 drug stores, 724 more than a year ago, including 323 stores acquired over the last 12 months.