I believe the OP's point is that really isn't when it not be effective but when you are supposed to throw it away as per the FDA. It could very well be effective well past that expiration date.
Almost all of the drugs I have in my cabinet are expired, and all have been 100% potent as the day I got it when I needed to take it years later. I have known this for a long time. There is also a reason the expiration date on your prescriptions is exactly one year after you get it from the pharmacy, when those bottles are actually sitting in a different bottle for months and months at the pharmacy. The entire reason for a 1 year expiration date is money.
For prescription drugs in the hands of consumers, as opposed to hospitals and pharmacies, I would be concerned about consumers misusing drugs.
For example, suppose someone goes to their doctor with certain symptoms and are diagnosed with a specific condition. They are prescribed a drug to treat it. They use up half the prescription, and the condition goes away.
A couple years later they develop similar symptoms. Instead of going to the doctor and getting diagnosed they just assume that it is the same thing the had before, and so start taking the drug again.
If they are right, great. They have saved the time and cost of a doctor visit. But what if they are not right? What if this time they have something different that just shares some major symptoms with the prior illness, but that needs a different treatment? Worse, it could even turn out that the side effects of the drug make what they have this time worse.
