This is part 2 in our special series about antibiotics controversies. See part 1, about fish antibiotics for humans, here.

Do antibiotic expiration dates matter?

by Leigh Ann Hubbard

The expiration date is not a magic number. This is one of the first things preppers (preparedness-minded people) learn when they start stockpiling. Shelf-stable products tend not to suddenly go rancid on the stamped date. Sometimes they last a long time after that.

Their quality, however, may begin to decrease. A can of vegetables that’s a while past its date may not taste as good. A supplement may be less potent. An antibiotic may not work as well.

The first two situations won’t necessarily kill you. That last one? It could. If the antibiotic doesn’t pull its weight, you’re at the mercy of the infection—which, thanks to that weak medicine you just took, has likely mutated into an antibiotic-resistant strain. Whoops.

So as a prepper, if you store antibiotics, should you immediately replace them when they’re expired? It’s a much-discussed topic online since antibiotics aren’t like ibuprofen. If they don’t work exactly right and you’re in a survival situation, it’s bad news. Really bad news.

Some people say, “Yes!! Replace them immediately! Even before!”

Others say, “No, they’ll last at least a decade, if not longer! Don’t worry about it.”

It’s a tad confusing. So who’s right?

We set out to suss out the answer. Like many prepper questions, this wasn’t easy to solve. Through weeks of investigation, we uncovered both gray areas and clear facts. But taken together, they paint an interesting picture of what the longevity truly is—for antibiotics and many other pills. We present our findings here, to help you decide for yourself which meds to trust and for how long.

What That Expiration Date Really Means

In the U.S., a medication’s expiration date is like the pharmaceutical company’s guarantee: they stand by the product until that day; after that, all bets are off. The med has been tested and proven to hold up that long—if the container is unopened and stored correctly.

“It would be very unusual for a drug to have an expiration date shorter than one year or greater than five years,” Craig K. Svensson, PharmD, PhD, dean of Purdue University’s College of Pharmacy, said via email. The reasons for the limits are complex, but it’s clear that especially for pills (as opposed to less-stable liquids), the date doesn’t always mean the drug won’t last longer. It’s often simply how long the medication has been tested for.

But here’s the twist: for prescription medicines, the manufacturer’s expiration date may not even be the one you see.

When a pharmacist dispenses a drug, they assign it a discard date, usually one year from the date of dispensing (unless the manufacturer’s expiration date is sooner than that). That’s because the prescription is only valid for 12 months, explains the National Community Pharmacists Association. If you bring that bottle back to the pharmacy for a refill and it’s over a year old, the pharmacist knows you need a new prescription.

Also, once the drug is removed from its original packaging and sent home with the patient, it’s exposed to damaging environmental effects, such as humidity and heat, so it won’t last as long as it would have in its original home.

“By the time you get prescription pills, the expiration date is at its shortest and most prudent.”

Bottom line: by the time you get prescription pills, the expiration or “discard” date is at its shortest and most prudent.

But here’s where twist two comes in: in 1986, the U.S. government decided that all this prudence and limited testing weren’t cutting it—for itself anyway. So it set up its own study to determine what we all want to know: how long drugs actually last. It’s called the Shelf Life Extension Program. And it’s changed how many people thinks about medication longevity—maybe a little too much.

The Great, Big Longevity Study

Referred to as SLEP, the Shelf Life Extension Program has provided unprecedented information about medication longevity.

SLEP started in 1986 as a way to save the U.S. government money. The Department of Defense stockpiles medications in case of emergency. (Feds, they’re just like us!) The agency grew tired of spending millions of dollars replacing those meds once they expired. So it decided to see if the medications would last past their expiration dates.

SLEP was established in cooperation with the Food and Drug Administration. In the program, certain important stockpiled medications are kept well past manufacturer expiration dates and are periodically tested to make sure they’re still good.

The medications in SLEP are divided into lots. Each lot usually goes through two testing processes:

  1. Accelerated stability testing: A sampling from the lot is stored under bad conditions for 60 days: 122 degrees F and 75 percent humidity. The results indicate how long the drug would probably remain good if stored ideally. The lot is given a new expiration date based on this data.
  2. Room temperature testing: After the new expiration dates are assigned, the lot is stored under optimal conditions, and a sample is retested once or twice a year to make sure it’s still good.

The FDA says it errs on the side of caution when extending expiration dates. However long they think the med will last, they mark the date sooner than that. Currently, no drug gets an extension longer than 10 years past its original expiration date.

But 10 years is a lot longer than one. So the fact that some medications last this long is quite interesting, eh? Except … the thing is, in SLEP, medications are stored under absolutely ideal conditions. And there’s the rub for preppers.

How Real Is “Ideal”?

Though SLEP is often cited as proof your antibiotics will outlast your dog, what’s not often emphasized is the fact that most people don’t store their prescription medications ideally, like they’re stored in the study.

The best way to store antibiotics to make them last.

The bathroom medicine cabinet is one of the worst places to store antibiotics.

For one thing, at home, prescription meds are usually in a pharmacy-provided pill bottle, not factory sealed, noted Svensson. These bottles aren’t humidity proof, “which is one reason that it is generally recommended that they not be kept in a bathroom that has a shower,” he said. (You’ve probably heard similar advice: the bathroom medicine cabinet is one of the worst places to store meds.)

Also, sometimes medicines are left in cars or otherwise exposed to extreme temperatures. Life is just not as ideal as a cozy SLEP warehouse.

So before applying the SLEP findings to your stash, consider that in the program, the medications are stored in the original packaging and always exactly according to the manufacturer’s labeled instructions.

How to Store Antibiotics at Home

So first things first: let’s just get your antibiotics to last at least to the expiration date you’re given. To do that, store them in tight containers at room temperature (59 to 86 degrees F).

Even if the pills get really hot one time (for example, you leave them in the car on a hot summer day), that could be enough to render them unusable, Prabhavathi Fernandes, Ph.D., founder and president of Cempra Pharmaceuticals, said in an email interview. “Some of them could be partially or completely destroyed. Some could be fine.”

Storing the pills below room temperature, however, might not be a bad idea. “Refrigeration will prolong the life of most drugs. But each drug will behave differently,” said Fernandes, whose company is focused on developing antibacterials. “Once opened, one must be careful, as some of the tablets may absorb moisture. Freezing could prolong life, but some drugs may be unstable to a freeze-thaw cycle. Repeated freezing can cause a drug to break down.”

Some preppers wonder whether vacuum sealing could help. Fernandes thinks it might but in most cases isn’t necessary.

If you’re thinking about storing your pills in a container other than the one the pharmacy gave you, consider that the United States Pharmacopeial Convention, which sets quality standards for medications, even has standards for packaging material. For example, manufacturers must ensure plastic doesn’t leach into the drug or vice-versa.

“Most liquid drugs must be refrigerated and have a short life. They should not be used past their expiry date.”

It should be noted that all of these storage instructions are about pills. Liquid antibiotics have their own concerns. “Most liquid drugs must be refrigerated and have a short life,” Fernandes said. “They should not be used past their expiry date. In addition to the drug, there are excipients added for flavoring, color, etc., that can also go bad.”

Essential Drugs: Practical Guidelines (2013), a guidebook for health care providers from Médecins Sans Frontières, or Doctors Without Borders, advises, “Freezing may be detrimental, particularly for solutions, leading to the precipitation of active ingredients or the shattering of ampoules.” (Doctors Without Borders is a humanitarian organization that provides medical care where it’s hard to access, such as in countries affected by conflict or natural disasters.)

What Happens When an Antibiotic Pill Goes Bad

So what’s the big deal if an antibiotic does go bad?

Well, there’s good news and bad news. The good news is toxicity usually isn’t a concern. “There are very few medications that actually break down into something that could specifically cause harm as the product ages,” said Svensson, the dean at Purdue’s College of Pharmacy. “An example would be [the antibiotic] tetracycline, whose degradation products can cause liver injury.”

The bad news is a decrease in potency is a concern—a big one. “The use of expired antibacterials does not cure an infection and also favours the emergence of resistant strains,” says Essential Drugs. In other words, you’ll still be sick—only now possibly with mutant bacteria. Even a just-from-the-factory version of that antibiotic probably won’t kill your newly resistant bugs.

You’ll also have contributed to antibiotic resistance outside yourself. If a family member catches your illness, they’ll have those antibiotic-resistance germs.

Can you tell whether an antibiotic is bad by smelling it?

Like bad meat, a weakened antibiotic doesn’t usually smell or look any different.

Just try a different antibiotic? They’re often not swappable. Most illnesses have one or more preferred antibiotics that work better for them.

Can You Tell Whether an Antibiotic Is Bad?

Sniffing meat left on the counter does not tell you whether it’s gone bad. The same goes for antibiotics.

“The stability of the antibiotic within a tablet or capsule cannot be judged by simply looking, smelling or tasting the tablet or capsule,” Svensson said. “The same is true for a liquid antibiotic. Occasionally, a suspension will physically look different as it ages, but the potency of the antibiotic will often be reduced prior to the time the physical appearance changes.”

However, if an antibiotic does have an altered appearance, that’s a warning sign, according to Essential Drugs. For example:

In time, certain drugs undergo a deterioration leading to the development of substances much more dangerous, thus an increase in toxicity. Tetracycline is the principal example: the pale, yellow powder becomes brownish and viscous, its use therefore being dangerous even if before the expiry date.

“An increase in allergen strength has been observed in certain drugs such as penicillins and cephalosporins.”

An increase in allergen strength has been observed in certain drugs such as penicillins and cephalosporins [both antibiotics].

Suppositories, pessaries, creams and ointments that have been melted under heat should not be used. The active ingredient is no longer distributed in a homogenous manner.

How Long Specific Antibiotics Can Last

So now you’ve gotten all this bad news and a little good news, and the question remains: If you store them under ideal conditions—factory sealed and everything—how long can antibiotics last?

The answer, for most of them, is longer than their expiration date. How much longer varies quite a bit, from around one year to, in a few cases, more than 10.

A 2006 report published in the Journal of Pharmaceutical Sciences summarized SLEP’s findings from the previous 20 years. Below are the antibiotics included in the report.

You’ll notice that there’s quite a variation in extension times. Experts we spoke with cautioned that each antibiotic is different. If one lasts 10 years, that doesn’t mean they all will, by any stretch. If an antibiotic you’re curious about isn’t included in this list, you can’t make any assumptions. There’s even variability from lot to lot. One lot may last five years; another lot of the same medication may not.

One note: You may wonder what “powder” refers to in this list. That’s a powdered form of the drug, which pharmacists use to make injectable solutions.

      Extension Time (Mos.)
Antibiotic Dosage Form No. Lots Tested Mean Range
Amoxicillin sodium Tablets 21 23 22–23
Ampicillin Capsules 5 49 22–64
Ampicillin sodium Injection-solution 8 57 29–87
Cefazolin sodium Powder 10 82 63–110
Ceftriaxone sodium Powder 4 60 44­–69
Cefoperazone sodium Powder 4 46 25–57
Cefoxitin sodium Powder 10 24 24–55
Cephalexin Capsules 6 57 28–135
Cephaprin sodium Powder 13 74 50–114
Chloroquine HCl Injection-solution 4 64 27–98
Ciprofloxacin Suspension 7 32 25–40
Ciprofloxacin Tablets 242 55 12–142
Clindamycin phosphate Injection-solution 31 44 18–77
Doxycycline hyclate Capsules 13 50 37–66
Doxycycline hyclate Powder 31 27 14–52
Doxycycline hyclate Tablets 169 27 15–91
Erythromycine lactobinate Powder 4 60 38–83
Neomycin and polymyxin B sulfates and bacitracin zinc Ophthalmic ointment 5 28 12–40
Penicillin G Powder 15 49 22–95
Penicillin G benzathine Suspension 4 70 61–84
Penicillin G procaine Powder 7 70 67–72
Primaquine phosphate Tablets 12 55 41–80
Spectinomycin HCl Suspension 8 83 55–109
Sulfacetamide sodium Ophthalmic ointment 4 39 35–44
Sulfadiazine silver Cream 37 57 28–204
Sulfadozine and pyrimethamine Tablets 8 67 34–93
Sulfisoxazole Tablets 4 56 45–68
Tetracycline HCl Capsules 11 50 17–133

A different SLEP paper, last updated in 2009 (click here to download the doc), got dosage-specific about a few drugs. These are the two antibiotics included:

Product Length of Original Dating Average Total Years Extended Total Shelf Life Obtained
Doxycycline 100mg tablets 2 years 5 years 7 years
Ciprofloxacin 500mg tablets 3 years 10 years 13 years

Finally, in a study unrelated to SLEP from the Institute of Pharmacy at the University of Tartu in Estonia, researchers tested antibiotic tablets and capsules they found that were at least 10 years expired.

All of the antibiotics, which were manufactured in various countries, passed their test: they contained a level of active ingredients that was acceptable by U.S. Pharmacopeial Convention standards.

The medications had been stored at the department of pharmacy at the University of Tartu in a closed cupboard at room temperature (about 68 degrees). “Some of the packages of the plastic vials of the expired formulations were opened and closed again, but none of the tablets or capsules tested was during the storage years directly exposed to the environment,” the study says. “The formulations in blister packages were not opened.”

The study doesn’t appear to have been published in any peer-reviewed, English-language scientific journal. The antibiotics, tested during the second half of 2011, were as follows:

Antibiotic Type Brand Dosage Form Expiration Date
Amoxicillin Upsamox Capsule, 500 mg 12/01
Amoxicillin Upsamox Capsule, 250 mg 7/01
Amoxicillin Moxilen Capsule, 250 mg 6/97
Ampicillin Pentrexyl Capsule, 500 mg 12/99
Ampicillin Apo-Ampi Capsule, 250 mg 12/00
Doxycycline Apo-Doxy Capsule, 100 mg 5/95
Doxycycline Doxy-M-ratiopharm, 100 mg Tablet 12/31/94
Doxycycline Doxycyclinum, 100 mg Capsule 2/1/99

The researchers caution that they “in no way promote the use of expired medications,” especially since this was a laboratory study, not one done in people to confirm whether the drugs in fact remained effective. But they also say, “neither was it completely out of the study to give any hint on the therapeutic value of these expired medications. Further studies are essential to verify the clinical efficacy of the expired antibiotics.”

What It All Means for You

After considering all this information, it’s clear that it’s most prudent to replace stored antibiotics before they expire. Taking expired antibiotics, especially if they haven’t been consistently stored optimally, poses risks that could be life threatening.

“It is evident that a drug does not become unfit for consumption the day after its expiry date.”

But what if you’re in a survival situation already and all you can get are expired antibiotics? This becomes a judgment call. You can hope your body is able to fight off the illness without antibiotics or that the disease is actually viral (in which case antibiotics wouldn’t work anyway), or you can chance taking the drug. Either way, there are potential risks.

“It is evident that a drug does not become unfit for consumption the day after its expiry date,” Essential Drugs acknowledges. For medications in general, if they’ve been stored optimally and “modification of aspects or solubility have not been detected,” Essential Drugs advises:

[I]t is often preferable to use the expired drug than to leave a gravely ill patient without treatment.

Expiry dates for drugs that require very precise dosage should be strictly respected due to a risk of under-dosage. This is the case for cardiotonic and antiepilectic drugs, and for drugs that risk becoming toxic, such as cyclines.

Often for survival scenarios, there are no easy, black-and-white answers, even for highly trained health care providers. The best plan, as with many things, is excellent preparation.

If you choose to store antibiotics, store them constantly as directed, and replace them before you have to worry about the expiration date. That way, if you do get into a survival situation, you’ll know you have a little wiggle room to work with.


Leigh Ann Hubbard has been a health journalist for over a decade. She’s the editor of and the owner of Revolutionary Writing Consultants, a writing agency specializing in health. 

Don’t miss part 1 of this series: Do fish antibiotics work in humans?