While physicians may not be able to recommend the use of expired medicines, it is likely that most drugs remain effective long after the expiration date (Arch Intern Med. 2012;():1-2. doi:10.1001/archinternmed.2012.4501).

In this study, investigators identified eight long-expired medications with 15 active ingredients that were discovered unopened in original containers in a retail pharmacy.  All had expired 28-40 years prior to analysis.

12 of 14 tested drugs retained at least 90% of the labeled amounts.  The authors also note that testing of federal drug stockpiles has shown that 88% of 122 different drugs stored under ideal conditions had their expiration dates extended by more than 1 year (average was 66 months) (Biosecur Bioterror 2009; 7: 101-7).

Given the expense of medications, examining expiration dates would yield significant cost-savings.