Objective  To describe the history of generic prescription pricing programs at major pharmacy chains and their potential implications on prescribing, quality of care, and patient safety.

Data sources  Publicly available generic prescription discount program drug lists as of May 1, 2009.

Summary  Fierce competition among major pharmacy chains such as Walgreens, CVS, and Walmart has led to a generic prescription pricing war with unclear public health implications. Introduced in 2006, currently 7 of the 10 largest pharmacy chains advertise a version of a deeply discounted medication (DDM) program, accounting for more than 25,000 locations nationally. By early 2008, almost 70 million Americans had used these programs. Although DDM programs lower drug costs for many patients, DDM formularies include potentially ineffective or harmful medications, have the potential to influence physician prescribing behavior, and may impair pharmacists' ability to review complete drug-dispensing records.

Conclusion  DDMs are widespread but have the potential for unintended consequences on patients, providers, and the health care system. A systematic review of DDMs needs to evaluate the clinical, economic, and system-level implications of such programs.