Jef Peckham, who has been quoted on this here blog before, sent me this…
Reading about your disappointing visit to Costco, and the bit about the expiration dates on the low-dose aspirin you found there, don't worry about it. Most pharmaceuticals do not go bad (note I did not say all). Many drugs including aspirin never go bad unless the various ingredients somehow precipitate out and separate themselves from the other ingredients.
The main reason for this is improper storage. You may have seen some drugs (normally ointments and creams or injectibles like insulin) that say on the packaging to "store between 50 and 85 degrees F" or something of that nature. Those drugs pose the highest risk for ingredients separating and becoming ineffective. Stable medications like aspirin are still effective for years after their "expiration dates." Aspirin (just to keep it on topic) didn't have an expiration date at all until it became a requirement.
Yes, requirement. The Food and Drug Administration back in the late '60s or early '70s issued a requirement that all medications have an expiration date, usually five years after a drug is manufactured or packaged, unless the medication itself warranted a shorter time span. In many cases the five year timeframe had nothing to do with the effectiveness of the medication. My late father, a pharmacist for 50 years, jokingly speculated that it was simply to force him to replace old pills and keep the drug companies in business.
You're probably right about the aspirin not really "expiring" and he was probably right about the motives for the dating. I do though feel there's something wrong with me buying aspirin this week which I won't be taking until May of 2017. I mean, I love Costco but I'm a single man and there are times when I look at the ketchup as they sell it and think, "Do I really need to buy ketchup I won't use up for three years? Maybe I should adopt a family of eight."
It just seems to me that the expiration date should have some connection to reality. They shouldn't be selling you a two-year supply of aspirin and telling you it expires in eighteen months even if it can be taken for years after that.
I have an odd thing about reading expiration dates on products. Often in markets, I alert the staff that they're selling certain items past the printed expiration dates and some of these are items where that really matters.
When I buy cereal, I occasionally note the expiration date on a box and think to myself, "Gee, I could buy this box of cereal now and leave it in my closet for months until I'm ready to open it…or I could come back here in eight months and maybe buy this exact same box of cereal."