Prescription Drug Price Information Act - Amends the Federal Food, Drug, and Cosmetic Act to require prescription drug retailers to post the prices of certain commonly prescribed drugs for the general public.

Directs each drug retailer to prominently post a list of the prices of the 100 prescription drug products that had the highest dollar volume of retail sales by such drug retailer within a period to be determined by the Secretary of Health and Human Services.

Requires the posting for each such drug to: (1) list the drug product under its established name (if any) and its proprietary name (if any); and (2) contain the lowest price at which such drug product is offered for sale in the most commonly dispensed quantity.

Prohibits the sale of any prescription drug product whose price is so posted: (1) at a unit price greater than the posted one, if the quantity sold is equal to or greater than the posted quantity; or (2) at a unit price greater than 110 percent of the posted one, if the quantity sold is less than the posted quantity.

Provides for injunctive relief to enforce this Act.