2 Questions about expiration dates on meds

First, what determines the expiration date on medications? Is it just the chemistry of the compound and how stable it is? The reason I ask is because I was just doing my yearly cleanup of the medicine cabinet to trash the expired and I found some Percocets that will expire in 2013. Considering that these are super regulated (or so they want you to think with all the warnings on the label), wouldn’t it make sense to give them a very close expiration date?

I was prescribed 30 earlier this year when I lost a toenail to an accident and only used 2. In my case, they just found their way to the garbage bin, but I can see someone peddling them in the black market. 5 years is a long time for a controlled substance to be around looking for unintended uses.

Is there anything that prevents pharmaceutical companies to either make medications degrade faster or just label them with a shorter life?
Second, are medications expected to expire and degrade safely? Is an expired medicine just useless or can they be actually dangerous/toxic? My MIL is the kind of person that stocks medicines and gives them to you for any reason without even reading the label (this is why we never leave our kids with them anymore, one scare was enough). We normally make the show of being sick, just so we get medicines from her to throw away and deplete her stash. Expired medicines are the norm. Will we one day get the call saying someone died from old medicines in that house or are they just eating inert pills?

I help round up expired medicines and ship them to places like Bangldesh, India, etc. I know U.S. docs and happen to become friends with someone opening a modern medical center in Bangladesh and some Asian countries.

The doctors providing them and receiving them laugh off the expiration date. The general feedback I receive is that is almost arbitrary and that most medicines have a much longer life than the very conservative expiration date.

However, a U.S. hospital had to abide by the expiration date.

A bit anecdotal – I know – but should speak a little to the issue.

If that is the case and expiration dates are just arbitrary, then I am even more surprised at the long life of controlled medicines. They should “expire” in two months from the date of purchase. That would eliminate at least the most nervous druggies (although now that I think of it, they probably don’t buy them in the recipient with a printed label)

First google response from “medication expiration date”: http://www.health.harvard.edu/fhg/updates/update1103a.shtml

The expiration date is the date at which the manufacturer can no longer guarantee that the medicine is at full potency. It may be at reduced potency, which may be acceptable for some medicines, but not others (e.g. a reduced potency antibiotic would be a bad thing). Nothing about accelerated expiration dates for black market valuable meds. Not really sure that would work anyway - if you’re willing to pay for black market percoset, I don’t think the expiration date would matter a lot to you. Supposedly, expired meds are not dangerous.

The problem with reduced potency meds is there’s no data on how much their potency is reduced. If you’ve got a med that’s 1 year past it’s expiration date, how much do you take? 1.5x? 2x? 6x? No one knows, which is why it’s not a great idea to take expired meds. You may undermedicate, which ranges from pointless to dangerous, and you may overmedicate, which is probably just dangerous.

On one hand, you have the actual “life expectancy,” which will depend on the medication’s physical, chemical and biological characteristics. You could have for example a cough syrup which is chemically stable for a long time but it’s a suspension so it can “cut” into two phases, like mayo or milk (which are suspensions).

On the other, many medications get a date that’s arbitrary. They have pretty long actual lifes, long enough that it hasn’t really been determined. This is the case for many pills that list expiration dates over a year. Similar situations happen in the chemical and food industries: in Spain, canned foods used to indicate when they’d been canned, but not an expiration date. Now they have to indicate an expiration date, so the canning industry made it five years, which is the maximum the law allows for.

In some cases, it’s possible for the manufacturer to modify the official shelf life of products once they have enough information. I’ve worked in chemical companies where new products were initially listed as “3 months,” so that the first batches produced would get retested at 3 months and every month thereafter; once we knew enough about the actual stability, we’d leave it at 3 months or define a higher value. The food and pharma industries often are more limited in how far they can go with this value.

In every chemical industry where I’ve worked and which dealt with expiration dates, if a batch was retested around its expiration date and found OK, it would get relabeled with a new expiration date (most companies would do this only once per batch). Logically, the production date didn’t change. In the only pharmaceutical company where I’ve worked, they did change the production date so that the new expiration date and the “new” production date would still be as far apart as the “shelf life” indicated in specs… if souls exist, that job killed a piece of mine :frowning:

I only find a “discard after” date on the percocets I got last week, and the date is less than a year away.

I think there must be almost NO sweeping statements one could make about minimum lifetimes for all medications, because there is nothing in common between all the substances that have medically exploitable effects on humans. To create a somewhat silly example, I got some Technicium 99 salts in an injection a year ago for a stress test, and this medication - well, not medication, but injectable substance used in medical procedures - loses half its strength every few hours.

I was taught that Darvocet breaks down into a toxic compound past its expire date. (can find a cite though). However, your percocet should be all right.

More importantly, if you have any questions about your medications ask your or pharmacist.

Cindi RN

I am sure my Percocet is alright since it still has 5 years to go before it expires. The question is purely academic.

And I understand that medicines come from all kinds of sources and have little or nothing to unify them as chemicals. Still, business practices are a lot more stable, predictable and applied more widely than chemical properties.

What I take from the provided link and Nava’s response is that pharmaceutical companies will try to put an expiration date that is as far as they can guarantee the product is good. That is not to mean that once past it is not good, just that they cannot guarantee it.

This is, it seems, the simplest way to go about it. Stick to the science and leave the moral complexities to the philosophers.

That Napier’s percocets have a close “discard” date does sound like an effort to push them out of circulation before they actually expire. I wonder if there is some law that prevents them from labeling it as an expiration date and thus the “discard” word is used.

I doubt that all this will make me change my practice of throwing away expired medicines, though.

I assume that there is no effort to collect medications from end consumers, right? That those expired meds sent to other countries come always from the manufacturers. The idea of post-consumer meds is a bit scary.

In Quebec, ALL prescriptions expire a year after being filled. The result is that the expiration date is meaningless and I pay no attention to it. I still have 50 narcotic pain killers that I was prescribed nearly three years ago when I was sent home after having a broken ankle set and never used even one of. I am saving them for an emergency. About 15 years ago, I had a back so bad that I could not stand or even sit for more than 90 seconds without excruciating pain and no one would prescribe a pain killer over the phone and it would have been impossible to go for a doctor’s visit, not to mention a hospital emergency room. When my regular physician returned from vacation a couple weeks later he did prescribe something sight unseen and only then did I start to improve. But when I say I keep these for emergencies, I have my reasons. I would really like to know when, if ever, they become dangerous, but the medical profession has decreed that I not know.

I used to work for a company that made herbal products. Not drugs, but we liked to pretend they were similar. When my boss started, a few years before I did, they determined expiration dates by walking across the street to Wal-Mart and seeing what kind of dates were on their competitors’ products. Note: this would be illegal to do if we were making actual drugs. One of the things my boss instituted was a proper expiration date testing program. Samples were taken off the line periodically, allowed to age, and tested for potency every few months to years. There was some cutoff we used - I forget what it was - 85% maybe? - to determine an expiration date.

I recently read in the internet that it is dangerous to flush expired medicines down the toilet because they get into the water supply. Which brings another question. If expired medicines are no longer any good, why is it dangerous to flush them?

The medicine may be “no good” because, say, 15% of it has degraded to either an inert or possibly harmful molecule. The remaining 85% is still an active pharmaceutical. Many pharmaceuticals are robust enough molecules to survive the wastewater treatment process and end up in waterways where they can harm wildlife and/or find their way back to drinking water.

There is never a shortage of disgusting things in my kitchen garbage. I just make sure I toss medications outside their containers when garbage is at its very worst, this way they end up in a landfill surrounded by disgusting crap, in the off chance that someone finds them and wants to reuse them.

(US readers might be confused by this, but landfill scavengers are common elsewhere)

Would you flush old motor oil down the toilet? Whether they are expired or not, they can pollute the water supply. This can also be a problem if large numbers of people take a drug, and the drug or its breakdown products enter the water supply via the sewage system. Think of all the women who take birth control pills. Small amounts of hormones can cause real problems for other creatures, not just humans.

First, the expiry date on medications is not so much “arbitrary” as it is “this is how far we have tested it, we meet the legal requirements for a stability program and since we’d like to be able to make/sell more lots of this drug in the future, we will use this date so that the patients have to come back and get more”.

Second, by the time you hit your expiry date (2 years is standard, IIRC) your drug has not degraded 15%. Or 5%. At most, as required by law, it has degraded 2%; in fact, it must be within 98-102% (or 98.0-102.0%, I don’t have the USP/EP/JP etc in front of me) of it’s original potency. In addition to that, any harmful (to any extent) impurities that may have formed cannot exceed more than a given amount, which depends on the impurity, so while your drug can still be 99.8% active, you might have reached a 0.2% impurity value for something by the time you hit 2 years, and so you have to stick a one year expiry on it. Basically, the expiry date is as close to a guarantee that the drug is the same as the day you bought it as you can get (provided you stored it correctly).

Stability programs: There’s the initial research stability programs, which establish what kind of storage conditions the drug can be kept under, and long-term stability programs, which is what the OP is talking about. The first one will test the drug at 0, 1, 2, 3, 6 months (maybe more) stored at 40C/75% relative humidity, 30C/60% RH, 25C/60% RH, 5C/Ambient RH. This way they can tell you to keep it in a cool place, to not exceed 30C, or keep it in the fridge. The later studies are usually done at something like 25C/60%RH or 25C/Ambient RH unless it had to be stored in the fridge or freezer, in which case you get 5C/Ambient RH or -20C/Ambient (very, very rare!).

The requirements for the long-term stabilities will vary from drug-to-drug, but in essence, they are all the same. The drug must pass the same criteria at the end of the stability period as it did at the beginning. When a lot is manufactured and is tested for stability, it is fully tested at T=0. That means that potency, impurities, colour and appearance, pH, density (if applicable), dissolution profile (if applicable), microbiology/bacteria presence and more will be tested. Samples of that lot will be stored as above, and removed for testing at 1,3,6,12, (18), 24, (30), 36 months. The variations depend on what previous/expected stability results have indicated is probable. Some months only some things are tested, others get the full range, but potency is almost always the main point of investigation. The colour might change, but if there’s no reason to believe it’s unsafe, that might still be ok (Listerine has a warning on it’s label about it becoming cloudy… technically it’s a “fail” for physical appearance, but it has no affect on the product or its efficacy, and so it is allowed to continue to be sold).

Now, if something tests out of range, there is a whole investigation that happens to make sure that it is a product problem and not an instrument/analytical one (like dissolving in methanol instead of ethanol or something). An OOS (out-of-specification) during a stability study is not necessarily the end of the study, since there’s still a lot to be learned by continuing. Anyways, with all that compiled stability data, the risks vs benefits of a 12, 18 or 24 (or whatever) month expiry date are weighed, and a decision is made. So the product is manufactured, packaged and sold.

Here’s the thing; once a product is on the market, it will continue to undergo stability trials. I forget the frequency, but something like 1-2 lots of every drug manufactured at my former company was put into a 24 month stability cycle, in order to ensure that the product continues to be safe for the public. This is a legal requirement. This is also the way in which product defects are often found, and the triggers for recalls (people panic at recalls, but IMHO, they are kind of a good thing!)

North American law prohibits the repackaging and/or reselling of unused medication because there is no way to check that the product hasn’t been tampered with by whoever had it before. Even when a pharmacy chain returns boxes and boxes of unopened…uh…boxes of drugs because they are close to their expiry and they want a new shipment, they are typically destroyed (unfortunately).

If your drug has special storage conditions (fridge, keep away from light, etc), then I wouldn’t recommend using them much past the expiry date… keep in mind that a 1 year date usually means the drug passed at 18 and/or 24 months…there is a margin of error in this! Drugs which are more risky to use past their expiry dates are hormones (e.g. the Pill, HRT, etc), vitamins (e.g. cyanocobalamine, Infuvite), and antibiotics (penicillin, clindamycin, etc) and several of the new “biologicals” (Enbrel, Humera, etc). If the drug has no particular storage conditions (which is true of most tablets and capsules), then using them a year or so past the expiry date is probably OK (the drug is unlikely to have degraded), but there is no guarantee, because after about 36 months from manufacture, it is very, very unlikely to have been tested.

Somewhat rambling post, but I think that covers most of the questions brought up in the thread as of whenever I opened it. Feel free to ask more questions if you’d like. BTW; my qualifications are simply that I was an analytical chemist for two different pharmaceutical companies for about 4 years and did many, many stability assays!

[/Wanders off muttering about N*****3 and their request for 64 8-hour dissolutions in 10 business days]

merci for a great answer.

Since you are here, and unrelated to my OP. Do cough syrups (and similars) have sugar in them? Does this make them not ok to give to the kids after they brush their teeth?

Outdated tetracycline has been linked to kidney problems in a few isolated case reports.

That would depend upon the syrup, you’d have to check the ingredients. Some contain sugar (glucose-fructose), some contain artificial sugars (sucralose, etc), and some have other stuff entirely. Non-medicinal ingredients should be available on packages or package inserts, or you can always ask the pharmacist/visit the webpage (click on the info for doctors link to get more info than you care to have!)

As for giving it to kids after they brush their teeth… well, I’m not a dentist, but I’d be surprised if it were to cause any harm to their teeth if you only do it a few nights in a row a few times in their lives (if they are sicker than that, see a doctor!). Personally, the sugar would keep me awake, which would be more of a concern!

And because he’s slightly drunk, my husband has requested that I include this smiley in my post: :smack: because he thinks he’s funny.

I have nothing to add - I just wanted to complement mnemosyne on her fantastic post!

That was very informative - I didn’t even know I was interested in this topic. :slight_smile:

The sad thing is, it really wasn’t that interesting in practice… which is why I left my job and went back to school :wink: The theory was always much more interesting than the reality of it! Thanks for the compliment, though!

Re: tetracycline, it doesn’t surprise me that expired meds caused problems - tetracycline is an antibiotic, and as a general rule, they tend to degrade pretty quickly. A quick Google search indicates that liquid tetracycline should be kept in the fridge, while capsules can be stored at room temperature. That, to me, suggests that accelerated stability (30/65, 40/75) probably didn’t pass beyond a few months, if that. Various conditions can cause it to degrade, and that makes it unsafe, or at least risky beyond the proven expiration date.

I recall testing one product (not an antibiotic, but something new the client was trying to develop) which was stable as a cream at room temp and below, but turned to this ungodly clotted lumpy oily repulsive mess at higher temps. Needless to say, it didn’t pass it’s stability testing and so special storage conditions had to be assigned. AFAIK, this product is in clinical trials now, and is promising (although the drug component itself was a known molecule, the delivery/use of it in this case is new).