(Reuters) - Rite Aid Corp said on Thursday that Hurricane Sandy substantially damaged eight of its stores and it expects the storm will hurt comparable sales in November, after boosting some sales late in the month as shoppers planned ahead.

As of Wednesday night, 188 Rite Aid drugstores were either closed or operating with no power. At the height of the storm on Monday night, 790 Rite Aid stores were closed.

Rite Aid said that sales at stores open at least a year, or same-store sales, fell 1.1 percent in October.

Sales of general merchandise and prescriptions were helped as shoppers stocked up ahead of the storm. Rite Aid estimated that about 1.1 percent of a 1.5 percent increase in same-store sales of general merchandise and about 0.2 percent of a 4.7 percent increase in prescriptions filled at comparable stores came from pre-storm sales associated with Hurricane Sandy.

Eight stores have sustained substantial damage, and the number could increase as Rite Aid gains access to more locations. The company said it would re-open affected stores as quickly as possible. (Reporting by Jessica Wohl in Chicago; Editing by James Dalgleish)