CAMP HILL, Pa. — Declines in pharmacy and front-end business resulted in decreased same-store sales in January at Rite Aid Corp.

The drug store chain said Thursday that same-store sales fell 2.1% year over year for the four weeks ended January 23.

With the decrease, Rite Aid posted its eighth straight month of declined same-store sales. Earlier this month, the retailer reported that December same-store sales fell 1.8%. The retailer’s last same-store sales rise occurred in May, when it recorded a 0.6% increase.

In January, front-end same-store revenue dropped 2.1%, and pharmacy same-store sales were down 2.1%. The company noted that the pharmacy results reflected a negative impact of about 210 basis points from new generic introductions and a 1.1% decrease in prescriptions filled at comparable stores versus the prior-year period.

Rite Aid said total drug store sales for the four-week period fell 3.3% to $1.913 billion, compared with $1.978 billion a year earlier.

For the year-to-date period, same-store sales dipped 0.6%, including a 0.5% gain in the pharmacy and a 2.8% decline in the front end.

Total drug store sales for the 47 weeks ended January 23 were down 2.1% to $23.135 billion from $23.636 billion in the year-ago span.

As of January 23, Rite Aid operated 4,786 stores, compared with 4,907 stores a year earlier.