Can You Take Expired Amoxicillin?

In our latest question and answer, the pharmacist discusses whether or not amoxicillin expires and how long amoxicillin is stable for.

Question

I have an old bottle of amoxicillin and wanted to know if it was safe to take and whether or not they expire or go bad.

Asked by Jodi On Aug 27, 2021

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Aug 27, 2021
Last updated Mar 03, 2022

Key points

  • Amoxicillin stored in the manufacturer's stock bottle, unopened, generally expires two to three years from the date of production.
  • When dispensed to a patient, the expiration date your pharmacy uses is typically one year from the date of dispensing, although this will vary depending on the pharmacy you use and the laws in your state.
  • Amoxicillin powder for reconstitution, when mixed with water, expires after 14 days.
  • Expired amoxicillin products should not be used as they may not be as effective as they once were.

Hello and thank you for reaching out to us!

We're more than happy to help you better understand drug expiration dates.

Amoxicillin Expiration

Amoxicillin, like all antibiotics (and drugs for that matter), does expire.

Generally, when amoxicillin is stored in a pharmacy, unopened, and under controlled environmental conditions, the expiration date set by the manufacturer will be around two to three years from the date it was produced.

If you have amoxicillin that was dispensed to you from a pharmacy, it will have a much shorter expiration date (typically one year at the longest for tablets and capsules, and only 14 days if it is a liquid suspension).

Amoxicillin Dosage Forms And Expiration Dates

Now, the dosage form we are talking about is important when it comes to expiration dates.

There are multiple amoxicillin products on the market, all of which carry different expiration dates. Common amoxicillin products include:

  • Amoxicillin capsules
  • Amoxicillin tablets
  • Amoxicillin chewable tablets
  • Amoxicillin suspension

I get into more detail regarding expiration dates for amoxicillin in the next sections, but in general:

  • Solid dosage forms of amoxicillin (e.g. tablets, capsules) have a set manufacturer expiration date of two to three years from the date of production. This is the date that will be imprinted on the 'stock bottle' stored at the pharmacy.

  • Liquid dosage forms of amoxicillin, which are stored as powders in the pharmacy that need to be mixed with water prior to dispensing, also carry a two to three-year expiration as long as they have not been mixed with water yet. Once they are mixed with water (when they are dispensed to a patient), they expire after 14 days.

  • Every state has different legal requirements regarding the expiration date that must be labeled on a dispensed prescription. However, most states and pharmacies use a one-year expiration after the medication has been dispensed.

You may be wondering why a dispensed prescription very often has an expiration date that is sooner than the manufacturer's listed date. This is simply a way of ensuring product potency once the product has left the pharmacy.

In many cases, dispensed prescription medication is not stored appropriately. They are often exposed to excess light and moisture, especially if left in the bathroom, and these factors all affect product stability.

As such, most pharmacists will state that your prescription medication expires one year after dispensing, even if the manufacturer's expiration date is longer.

Where Do Expiration Dates Come From?

Most drug products, when stored according to the manufacturer's instructions (i.e in the original manufacturer's "stock" bottle at a specified temperature range), carry an expiration date of two to three years, depending on the manufacturer. There are a few reasons for this:

  • Stability studies are generally only run for a few years. A two to three-year expiration window is viewed as an acceptable time frame (i.e. shelf life) and eliminates the need for the drug company to perform longer, and more expensive, stability tests.

  • Putting a two to three-year expiration date on a newly manufactured product necessitates the purchase of additional, replacement products by the pharmacy once the previous ones expire.

When amoxicillin is within its expiration date range, and store appropriately, you can be confident it retains its original, labeled potency (within a small acceptable range).

Once amoxicillin has expired however, it may not have the potency it once had, as there generally is no stability data available past that time frame.

What Happens After Expiration?

After expiration, amoxicillin may still have its original potency and effectiveness, but there is no good way to tell and thus, should not be taken.

We do know that amoxicillin, as a molecular compound, does degrade over time, and that stability is temperature-dependent. One study reported the following results:

Amoxicillin degradation were time, temperature as well as concentration-dependent, resulting in short-term stability, in particular at high concentrations

What we don't know is just how quickly it degrades, as this is very situational (again, it depends on time, environmental factors, concentration, etc...) , and at which point it will no longer be effective. Taking amoxicillin that isn't as effective as it was when it was in date has the possibility of causing therapeutic failure.

Does Expired Amoxicillin Cause Harm?

It is important to note here that most expired drugs don't go "bad" in terms of causing physical harm.

One rare instance of this was reported in the 1960s with expired tetracycline, but modern pharmaceutical products are formulated to be more stable, and this wouldn't be expected to happen today.

In fact, it can be difficult to tell when a drug has degraded at all.

Some common products, like aspirin, will develop a foul odor, a clear indication of chemical change. However, these physical manifestations of drug degradation aren't common and do not happen in the case of amoxicillin.

There is little published data that would suggest expired amoxicillin causes harm, outside of the fact that it may not work as well to treat an infection.

Some studies report that several of the byproducts of amoxicillin breakdown, notably amoxicilloic acid and diketopiperazine, are known allergens, but there is no indication that someone who has previously tolerated amoxicillin well, would be allergic to these compounds.

So all in all, it doesn't appear that expired amoxicillin will hurt you, but again, it may not work well compared to non-expired amoxicillin to treat your infection

Expiration Of Amoxicillin Reconstituted Suspension

I want to quickly focus on the expiration of liquid amoxicillin products, which are technically reconstituted suspensions, since that is what your question was regarding.

As discussed, in addition to the solid dosage forms of amoxicillin, it also comes as a powder for reconstitution. These products are most commonly mixed with distilled water at the dispensing pharmacy and given to the receiving individual as a liquid suspension.

The expiration date of amoxicillin powder when stored at the pharmacy is 2 to 3 years, similar to the tablets and capsules. However, once the powder has been mixed with water and turned into a suspension, the product will expire after 14 days.

While not absolutely necessary, the reconstituted suspension should be stored in the refrigerator to ensure stability. At the very least, the product should not be stored in a location that exceeds room temperature (68 - 77 F).

Multiple studies show that amoxicillin, when exposed to high temperatures, degrades much more rapidly than products stored at room temperature or below. It is critically important to store the product appropriately to ensure stability. Chilled amoxicillin suspension is reported to taste better as well when compared to amoxicillin stored at room temperature.

Final Words

To summarize all of the above, as long as amoxicillin tablets and capsules are stored according to the manufacturer's guidelines (i.e.product is kept in a tight, light, and moisture resistant container at room temperature), the expiration date of amoxicillin is 2 to 3 years from manufacture.

Excess heat and moisture are known to cause degradation of amoxicillin, so it is important to store appropriately.

If you do have expired amoxicillin, it is not recommended to take it as it may have degraded over time and therefore, won't be as effective as it once was.

Taking a 'sub-therapeutic' dose of amoxicillin to treat your infection can have serious consequences.

You may not get better since the bacteria won't be effectively eradicated and potentially, you could be promoting bacterial resistance, which could lead to worse infections in the future.

To ensure you take a safe and effective medication, see your doctor or pharmacist for a replacement.

References

  • Stability study of six brands of amoxicillin trihydrate and clavulanic acid oral suspension present in Yemen markets, Journal of Chemical and Pharmaceutical Research
  • Post-marketing stability surveillance: Amoxicillin., TanFOnline
  • Decomposition of aspirin in the solid state in the presence of limited amounts of moisture, PubMed
  • Fanconi Syndrome (Adult Type) Developing Secondary to the Ingestion of Outdated Tetracycline, ACP
  • Amoxil Prescribing Information, AccessFDA
  • Overcoming stability challenges during continuous intravenous administration of high-dose amoxicillin using portable elastomeric pumps, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 11 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication related questions!

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