Drug expiry dates – are they ever too old?

DRUG BUST by Alan Cassels

• The people’s briefing note on prescription drugs

Portrait of columnist Alan Cassels

A little while ago I was talking to a physiotherapist who asked me if I was taking anything for some joint pain I was having. I pulled out a bottle of acetaminophen – also known as Tylenol – and she took the bottle from me.

“Alan,” she asked, with a bemused smile, “did you know these expired in May 2001?”

No, I didn’t. Shows how observant I am. Perhaps a 14-year-old bottle of Tylenol gives you some sense how infrequently I take the stuff.

It’s not the first time I’ve thought about the meaningfulness of expiration dates on our medications. Frequently, I wonder, “Does it make any difference taking drugs that are far past their expiry? And is it harmful to be swallowing medications that were made in the last millennium?”

Quick answers: probably not and probably no.

Health Canada requires drug makers to put expiry dates on their drugs, an acceptable precaution given that a drug’s ‘active’ ingredient may lose its potency over time. For some conditions, a drug’s potency is vital. The expiry date is the date by which a drug maintains its “labelled potency, purity and physical characteristics,” but it’s also “the minimum after which the manufacturer recommends that the drug not be used.” No one gives a maximum date.

From a merchant’s perspective, a short expiration date drives return customers. If your clients only use your product intermittently, expiry dates get them back to purchase more of the product. You often hear pharmacists and regulators hectoring about medication expiry dates, warning you in grave tones that you could be taking dangerous chances by swallowing expired drugs. Hmm, how true is that?

Phil Emberley at the Canadian Pharmacists Association in Ottawa answered some of my questions on this issue. His association enforces “standards of practice” for pharmacists and one of those “standards” is that pharmacies are not allowed to sell expired drugs. While such policy is there to protect the sanctity of the drug supply, Emberley admits the science around expiry dates is weak. Some drugs definitely lose their potency or stability over time – “drugs like insulin or epinephrine,” he says. But I wondered about expiry date economics. If a manufacturer’s expiry dates are ridiculously short, is this not a handy way to ensure patients are maximally gouged?

“I won’t wade into that one,” says Emberley. Understandably, pharmacists lean to the side of caution because they don’t know how well patients store their medications – where exposure to heat and humidity could degrade the drug. If a drug is stored properly, in the container it came in and away from light, heat and humidity, do you need to worry about its safety if it sails past the “best before” date?

I managed to track down the one guy who would know. Lee Cantrell is the director of the California Poison Control Centre based in San Francisco and is one of only a handful of researchers in the world who have studied the potency issue around expired drugs. And when I say “expired,” I mean “very expired.” The drugs he examined for a 2012 study in the Journal of the American Medical Association were 28 to 40 years beyond their expiry date.

He told me someone offered him access to a stash of unopened medications “squirreled in the back in a community pharmacy. As a scientist, I said, wow, this is a great opportunity to look at these medications to see if they could remain viable decades after they were produced.” He said he was never comfortable with the “relatively arbitrary process” used to dream up drug expiration dates and relished looking into the issue.

Mostly, it was the safety question that piqued his interest. He said he’d often get calls at the Poison Control Centre from people who discovered they’d accidentally swallowed an expired medication. “They’d freak out, saying ‘Oh my God, I just took an expired med, am I going to die?’”

His study looked closely at 14 expired drugs, 12 of which were “present in concentrations at least 90 percent of the labelled amounts.” This is considered the minimum “acceptable potency.” Basically, these decades-old drugs were as potent as the day they were manufactured; in fact, he found that those 12 medications “retained full potency for at least 336 months, and eight of these for at least 480 months.”

Lee Cantrell clearly doesn’t want people to think his research was an invitation to take expired medication. “That was not my conclusion at all. We didn’t study efficacy or safety, only potency,” he says.

Cantrell’s study was unique but tiny compared to what the US military did when it launched its Shelf Life Extension Program (SLEP) in 1986. Because the US government stores one of the biggest stockpiles of medications, it needs to know how potent those drugs are after their expiry dates. SLEP examined 122 different drugs past their expiry dates and found that almost 90% of them could easily have had their expiry date extended by a year. In fact, on average, they felt they could safely extend the expiry dates of those drugs by more than five years.

But there are caveats around this kind of research. The drugs in both Cantrell’s study and SLEP were stored properly, unopened, with both temperature and humidity controlled. And these were tablets and capsules, which remain stable much longer than drugs in suspension liquids.

The occasional pharmaceutical consumer might look at this and ask, “How much do those drug expiration dates really matter?” When a batch of yogurt or leftover pasta at the back of the fridge goes bad, your nose tells you, but with drugs, we have to take the manufacturer’s word for it.

One thing is clear: there is very little evidence that people can be harmed by taking expired medications. Anecdotes, however, are powerful. Every pharmacist in the world has had drummed into their heads a case study of expired tetracycline causing Fanconi syndrome in 1963. It should give one solace that, if citing a 52-year-old case study of an expired drug is the best they can do to scare you about the practice, it’s unlikely expired medications pose huge safety concerns.

For me, the lack of documented harms tells me that when (and if) drugs degrade over time, they may become useless, but they probably won’t become toxic. Today, drug companies are required to test their drugs for stability and will state on the label if the product, once expired, is risky.

Is it possible the biggest harm from drug expiry dates is not health harm, but economic and environmental waste? When people are warned, time and time again, to discard their drugs once they’ve become expired, are they filling landfills to pollute the environment and wasting their (and our) money? Ditching good, but out-of-date, drugs probably costs all of us hundreds of millions of dollars every year, but what’s the solution? I’m not suggesting a revolt at the pharmacy; what I am suggesting is better independent research on expiry dates to ensure that Canadian consumers can have drugs with reasonable expiry dates informed by science, not marketing.

This might have resonance at the national level. Back in 2004 or so, public health officials in Canada started stockpiling huge batches of antiviral drugs Tamiflu (oseltamivir) and Relenza (zanamivir) in case of an influenza pandemic. Said pandemic didn’t materialize. The drugs were good for probably five years from the date of purchase. So, in my estimation, Canada is sitting on two federal stockpiles holding about $150 million worth of antivirals and the provinces also hold hundreds of millions of dollars worth. BC’s alone is worth about $35 million.

I tried hard, but no one at Health Canada could tell me when and if these drugs were expiring. Let me hazard an educated guess: they are almost all expired and by next year, 2016, the entire stockpile will be expired.

Does Canada throw away hundreds of millions of dollars worth of expired drugs or spend a bit of money to find out if they might be effective? We’ve got a new government that might be interested in this kind of public-interest research. Stay tuned on this one.

Alan Cassels is a pharmaceutical policy researcher, an occasional swallower of expired acetaminophen and the author of a new book, The Cochrane Collaboration: Medicine’s Best Kept Secret. @AKECassels. You can read more of his writings at www.alancassels.com or follow him on twitter @akecassels

3 thoughts on “Drug expiry dates – are they ever too old?”

  1. Expired chemotherapy pills. The company that manufactured them. Said they’d not have full strength and could be more harmful than good. ! The pharmacy is at fault selling them. They can not “LEGALLY “ sell expired anything. Certainly not expired chemotherapy!

  2. Your discussion may be relevant for a dinner conversation only. For the average patient this another factor for them to get wrong. Yes, it may be harmful to take 10 year old acetaminophen, however if you are taking it to actually reduce symptoms or treat pain , it may be reassuring to know that the medication will in fact work. Before raising a more critical pint let me also suggest that rarely will medications be stored properly, therefore reduced potency is an issue. I would not speak for the pharmaceutical industry, however to perform 10 year stability tests would be impractical. Hence, put a 4 or 5 year expiry date on the bottle and package in a size that the consumer will use up in a reasonable period of time. (By the way there is a program in every province to dispose of unused medications. The last comment is on the risk of taking expired medications. It was noted there are a few mess which pose a harmful risk( epinephrine being one of these). As an aside a number of medications are place in Amber containers because they are light sensitive. Epinephrine is one of these drugs. I have a hard time trusting anyone who used outdated epinephrine. In todya’s world there are newer and more potent medications which can be harmful if not taken within the expiry time. Patients do not finish their course of therapy and save the 6-7 tablets “until the next time they get sick”. How do measure the waste of health care dollars when these people show up in emergency because they have taking old prescriptions thinking it was OK. Big picture ….let’s not confuse the patient . Thank you

  3. I’ve been a primary care physician for nearly 40 years. About 25 years ago, the Medical Letter, a relatively impartial and authoritative source of information on drug and other therapies published a review of expiry dates and their significance.

    Their conclusion, based on all available data they could find, was that for solid tablets and capsules, unless there was evidence to the contrary (or they had been stored improperly), they were effective and safe for about 10 years. For liquids and suspensions, they suggested following the manufacturer’s instructions, with the exception of drugs in sealed vials. In that case, duration was hard to estimate, but a great deal longer than what is usually stated.

    In the specific case of epinephrine or adrenalin (the main drug in Epipen kits and similar allergy treatments), they suggested that the drug was still effective if it was sealed glass vials and a) there was no precipitate (solid material on the bottom of the vial), b) there was no cloudiness, and c) there was no discoloration. I have used adrenalin that was well past its expiry date which fulfilled these three conditions, in emergency situations, and it has worked perfectly well.

    I note that some manufacturers of adrenalin now tint the vials, making it impossible to tell if the solution is discoloured. Is this a marketing ploy, to force discarding of vials of adrenalin after its expiry date? Knowing how clever drug companies are at enhancing sales, I wouldn’t be surprised if it was.

    No-one has done a proper study of expiry dates. The drug industry won’t do it, because it threatens sales and would probably break up their current system by showing that expiry dates are mostly meaningless. The professions like pharmacy and medicine and nursing won’t, because it’s been a mantra of theirs for years that expiry dates are important, and they (we) would look foolish. This sort of study will need to be done through public funding, where the public interest is uppermost — a nice project for the incoming Liberal government, particularly because it might mean saving that $150 million worth of drugs for flu (which aren’t all that effective anyway, but are popular with public health professionals) from being tossed in the dumpster (or rather incinerated in special high temperature flame units).

    This column is very helpful because this is an important subject that should be talked about more, and addressed. It isn’t because we’ve unwittingly taken the needs of corporations as our own.

    It’s time for a major change in policy around drug expiry dates.


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