| | Re: Stability after expiration date?
In general, I believe that it depends on the country you live in and the conditions around you. The reason is simple.
The government body which controls medication in your country helps the pharmaceutical company decide what is the best expiration date. Generally, the expiry date is set such that if that time period is crossed less than 90% of the drug is lost. That means after the expiry, less than 90% of the drug will still remain in the formulation.
The second factor which would control it would be the place where you are. The reason is environmental factors and storage conditions could result in loss of the active ingredient due to decomposition. In general, medicines decompose more slowly in cool, dry and dark places.