Does dog amoxicillin expire? Here’s the Answer

How long can you use medicine after expiration date?

What they found from the study is 90% of more than 100 drugs, both prescription and over-the-counter, were perfectly good to use even 15 years after the expiration date. Hence, the expiration date doesn’t really indicate a point at which the medication is no longer effective or has become unsafe to use.

Expiration Dates on Veterinary Drugs: Do They Matter?

If your January purge includes decluttering your medicine cabinet, you might find yourself wondering how important those dates stamped on various pharmaceuticals really are. You have half a tube of ointment from that one time Fluffy had an ear infection, a few pills rattling around from when she was so itchy last summer, and almost a full bottle of some type of pain pill from the time she sprained a paw.

Should you keep these things, and for how long?

Don’t worry, Animal Skin and Allergy Clinic has the scoop on expiration dates on veterinary drugs, so that you can stay on task with your decluttering resolutions.

All medications that we prescribe to our patients come with an expiration date. Typically, this date is clearly stamped or printed on the container provided by the manufacturer.

When we dispense a medication for your pet, an expiration date is also printed on the prescription label. This helps our pet parents know how to best use the medications we prescribe.

Expiration dates on veterinary drugs are important because, as time marches on, drugs lose efficacy and potency due to chemical changes that take place. Sometimes, though rarely, changes can take place that cause the medication to be harmful to your pet.

Each individual drug has its own unique shelf life determined by the manufacturer. Some last a very long time, up to several years. Others, like the Atopica for Cats liquid that we often prescribe, last only a few months.

It is not wise to rely on the drug’s appearance to assess whether or not it is still good. While some medications may change color or texture, this does not always happen.

Is human amoxicillin safe for dogs?

Human Amoxicillin Not the Same as Pet Amoxicillin

Mahaney, veterinary-specific medicines are the best option. The dangers of giving your dog human-grade amoxicillin, he says, include the potential to expose your dog to components of the drug that are “inappropriate” or “potentially toxic.”

Even though it might not be toxic past its expiration date, it may have lost some of its potency. If it’s not as effective in treating infection-causing microbes, it might even help these germs build immunity to the drug. That means the next time you need amoxicillin, it might have little or no effect.

Expired antibiotics typically lose some of their potency, which means it is unlikely they will be able to completely kill the bacteria that is causing your infection. If you are tempted to use leftover or expired antibiotics for a new infection, they are not likely to help.

CAN expired amoxicillin hurt you?

Chances are, your medication cabinet contains some pills for you or your pets that are past their expiration date. If you’ve wondered whether these older medications might still be OK to use, you are not alone. Researchers from the California Poison Control System, the University of California, San Francisco and UC Irvine also wondered. They satisfied their curiosity by testing the effectiveness of eight drugs that had been sitting in pharmacies, unopened, for years after they had supposedly gone bad. Those expiration dates were anywhere from 28-40 years ago!

14 active ingredients were present in the 8 products they analyzed. Out of those 14 ingredients 12 were still at high enough concentration – at least 90% of the amount stated on the label – to qualify as having acceptable potency. Aspirin and amphetamine were the two ingredients that were no longer acceptable. Many of the drugs tested were ones contained in over-the-counter products such as acetaminophen (Tylenol), caffeine, and chlorpheniramine, which is an antihistamine. Codeine, hydrocodone and several barbiturate medications were also tested.

The expiration date on a drug is usually one to five years after it was manufactured, and those dates are often set arbitrarily. You may be surprised to learn that the Food and Drug Administration doesn’t require pharmaceutical makers to test how long the active ingredients in their products will last.

The federal government has a Shelf-Life Extension Program which allows drugs in federal stockpiles to be retained for up to 278 months (23 years) after their stated expiration date if tests show they are still potent. Some of the ingredients tested in the California study remained good after 480 months – so far.

The analysis was published online by Archives of Internal medicine. The research team concluded “Our results support the effectiveness of broadly extending expiration dates for many drugs,” they wrote. “The most important implication of our study involves the potential cost savings resulting from lengthier product expiration dating. Given that Americans currently spend more than $300 billion annually on prescription medications, extending drug expiration dates could yield enormous health care expenditure savings.”

Most pet owners who have multiple animals sooner or later find themselves in possession of unused medications. Many times these leftovers come in handy. If your dog comes up lame on a Sunday and you have some Rimadyl on hand or your cat is bitten and you happen to have a few days worth of antibiotics it might save you a trip to the emergency hospital. How do you know what’s OK to use and what isn’t?

First, call us or bring in your old medications for us to sort through. We are always happy to help advise you on what to keep and what to throw out.

The National Association of Boards of Pharmacy (NABP) has recently released a report on the analysis of on-line pharmacies. 97% of the 10,000 websites they studied were in violation of U.S. Pharmaceutical laws. We recommend that you never buy any pet medications on-line from a pharmacy that is not accredited by the Vet-VIPPS program (Veterinary-Verified Internet Pharmacy Practice Sites). For more information, visit