Do antibiotics actually expire? And, if so, how long are antibiotics good after the expiration date? These are reasonable things to ask, especially if you find an old prescription bottle in your medicine cabinet.
You also aren’t the first to ask these questions. So, here’s a quick guide on whether you can take antibiotics after their expiration dates, along with reasons and suggestions.
Do Antibiotics Expire?
The short answer is yes. Antibiotics, like all drugs, eventually expire.
The Food and Drug Administration (FDA) makes it clear that expiration dates aren’t just for show. They indicate the point at which a medication’s potency, efficacy, and safety have been tested and confirmed by the drug manufacturer.
In other words, medications are only guaranteed to work as intended up to the printed expiry date. Beyond that, and we cannot stress this enough, there’s no assurance the antibiotic will still be effective or safe to use.
Because of this, the Center for Drug Evaluation and Research (CDER) recommends disposing of expired medications properly. This includes antibiotics that have passed their shelf life.
But what does prolonged testing reveal? Let’s take a closer look.
Can You Take Expired Antibiotics – Do They Lose Their Potency and Efficacy?
As mentioned, all medications lose potency over time. While antibiotics do go bad, prolonged testing has shown that many retain a significant portion of their effectiveness well past the printed expiration date.
Ongoing research suggests that, when stored properly, antibiotics may keep up to 90% of their potency for five years or more after expiration. Amoxicillin, one of the most widely prescribed antibiotics, is often at the center of this discussion.
That’s why questions like “Can amoxicillin go bad?” and “What happens if you take expired amoxicillin?” are so common. Research indicates that amoxicillin antibiotic expiration dates do not always mean an immediate loss of effectiveness.
One of the best sources of evidence of this comes from the Shelf-Life Extension Program (SLEP), a joint initiative from the FDA and the Department of Defense. Designed to reduce military medication costs, SLEP found that 88% of 122 tested medications, including antibiotics like amoxicillin, retained potency for more than a year beyond expiration.
It’s important to note, however, that these results came from medications stored in ideal environments. At home, storage conditions are rarely optimal, which means most antibiotics may not last nearly as long.
Do All Antibiotics Retain Potency After Expiration?
Not all antibiotics age the same way. Research shows that most solid forms, such as tablets and capsules, are more likely to retain potency after their expiration date. In contrast, liquid antibiotics degrade much faster and should never be used once expired.
Liquid antibiotics are particularly vulnerable because they can be contaminated after mixing or reconstitution. They also undergo compositional changes that alter their smell, taste, or appearance, making it easier to spot that they’ve gone bad.
Some antibiotics have a very narrow therapeutic index, meaning that even a slight loss of effectiveness could have serious consequences for patients. Monoclonal antibodies, for example, should never be taken past their expiration date.
Because results vary across different antibiotics and depend heavily on storage conditions, it’s difficult to predict exactly how long a medication will remain safe or effective. We’ll look at proper storage practices in the next section.
How to Store Antibiotics to Help Them Last
Proper storage is one of the biggest factors in how long antibiotics remain effective. Drug manufacturers always include storage guidelines on the packaging. Following them is the best way to protect a medication’s potency.
Generally, antibiotics should be stored in a cool, dry place, away from direct sunlight and heat. Leaving them in a car or anywhere exposed to extreme temperatures can cause the drug to degrade much faster. Sometimes it can even go bad before the printed expiry date.
To reduce this risk, keep antibiotic bottles tightly sealed and avoid areas with frequent humidity fluctuations, such as bathrooms. Signs that an antibiotic has spoiled early include noticeable color changes or an unusual odor.
Proper storage doesn’t extend a drug’s expiration date indefinitely, but it does help antibiotics stay stable for as long as possible.
Is It Safe to Take Expired Antibiotics?
Even if some antibiotics retain potency after expiration, medical experts strongly advise against using them. Once a medication has passed its expiration date, there’s no guarantee that it will still work as intended or be safe.
In most cases, the drug may simply be less effective, which means it won’t properly treat the infection. But in some situations, taking expired antibiotics could do more harm than good, from exposing you to side effects without the benefit of treatment to contributing to antibiotic resistance.
In a true emergency, a doctor may determine that using a just-expired antibiotic is better than no treatment at all. However, you should never make that decision on your own. Always contact a healthcare professional before taking expired medications.
Other Safety Concerns with Expired Antibiotics
Beyond the loss of potency, expired antibiotics can create additional health risks:
- Misuse and self-treatment: Taking old antibiotics may delay a proper medical evaluation and prevent doctors from diagnosing new or underlying conditions.
- Incorrect dosing: Expired prescriptions may leave you with the wrong dose or an incomplete course, both of which can be dangerous.
- Drug interactions: Your health may have changed since the antibiotic was prescribed. An expired drug could now interact with other conditions or medications.
- Unnecessary side effects: Even if expired antibiotics retain some potency, they can still cause side effects without effectively treating the infection.
- Bacterial resistance: Taking sub-potent or incomplete doses increases the risk of antibiotic resistance, when bacteria adapt and become harder to kill. This is a major public health concern.
- Gut health issues: Overuse of antibiotics, expired or not, can harm beneficial bacteria, leading to problems such as diarrhea, yeast infections, or even serious infections like C. difficile.
Which Antibiotics Become Toxic When Expired?
For most antibiotics, the primary concern after general medication expiry dates is loss of effectiveness. Not toxicity. However, there are rare but important exceptions.
Decades ago, a small number of cases linked expired tetracycline to a reversible kidney condition known as Fanconi syndrome. Researchers believe this toxicity was caused by tetracycline degradation products that developed after the drug expired. Patients experienced nausea, vomiting, and metabolic acidosis within days of taking the expired medication.
Fortunately, no recent cases of toxicity from expired tetracycline or related antibiotics such as doxycycline have been reported. Still, this example serves as a reminder that expired antibiotics can pose more than just reduced effectiveness. In rare instances, they may actually be harmful.
Can You Take Expired Antibiotics – Final Thoughts
We hope this has been useful in understanding whether you can take expired antibiotics. As always, this information is not intended as medical advice. We recommend consulting a doctor before taking or changing any medications.
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