I found a two or three year old bottle of hydrocodone while cleaning today. I threw it away, but got to wondering what would have happened if I took a couple. Do drugs like hydrocodone (it’s an opiate I think) stay good for a long time, simply lose their potency, or do they become poisonous? Does any particular type or general classification of drug have a really long shelf life, or should all drugs be discarded after a certain amount of time? You always hear warnings not to keep prescription drugs for too long (but never a definition of what “too long” is), but I’ve got aspirin and cough syrup and stuff that’s been on my medicine shelf long enough to accumulate a layer of dust on their respective bottles. I don’t get sick often and avoid medicine when I do, so when I do get something, whether it’s prescription or OTC, I tend to keep it for a long time. Plus, I’m a cheapskate. I wonder if my little private pharmacy is saving me money or if it’s going to turn me into an accidental suicide when I get a migraine some day. Are their any rules on this kind of thing? The pill bottles I have here don’t have expiration dates on them. They never covered this in Health Class.
Well, just off the top of my head, what happens to medicines as they age is like what happens to most other chemicals as they age (and to people): they change into something different. 
Why take a chance that what you’re swallowing isn’t really acetominophen at all, anymore?
The universal medical advice is to take all the medicine in the prescription and if you are too stubborn to do that, to dispose of unused medicine immediately
You will find that the experts who write forThe Medical Letter addressed this issue in the July 19, 1996 issue of The Medical Letter. You can access it in their public reading room at http://www.medletter.com/freedocs/expdrugs.pdf
Different drugs have different lifetimes. I’m not going to try and sum up what I ran across, just let me advise you to run a search at Google for hydrocodone shelf life.
My main 'scrip is one my doctor left me self-administering for several years and he never gave me any warning about its diminished efficacy or altered effect over the life of the pill. But I know other 'scrip medecines, particularly antibiotics, deserve research in that arena.
sigh I hate it when I do that - spelling booboo.
Incorrect. The medical advice should read “take the medication as directed”. If the prescription says take as needed for worse pain, and you no longer have worse pain, then don’t take it. Talk to your doctor as to whether you should keep it around for future problems. If you had hydrocodone for broken leg pain, and now it’s better, you can probably discard. If you’re taking it for infrequent but severe colonic spasms, you may need to hang on to it.
Even though opiates generally don’t turn toxic, they do get less effective with time. If in doubt, throw it out.
QtM, MD
You are, of course, right. That’s what I should have said.
Also, you should dispose of medicine by flushing it down the toilet (the contents, not the bottle, of course), rather than discarding it in the garbage. Otherwise it might fall into the wrong hands.
^ Ha, just what I need, a bunch of stoned cats and raccoons wandering around my neighborhood.
Thanks everybody for the info and links. 