Responsible pet owners often go through the experience of bringing in a pet to be treated by a veterinarian. When your pet is injured, sick, or has an infection, medication like antibiotics are often prescribed by vets. Once you've reached the end of the dosing for said medication, you might be tempted to save any that's left over for a later time. Here's why you shouldn't keep the medicine around for this purpose.

Wrong Medicine

If your pet has a chronic issue that flares up from time to time, like conjunctivitis, it might seem tempting to just give your pet the medication that they already have. Unfortunately, this is often the wrong idea.

Medications for pets are carefully tailored to your pet's individual needs, just like medication for people. In the example of conjunctivitis, a simple antibiotic may be beneficial in helping to kill the bacteria responsible for causing the problem. However, if your pet has developed viral conjunctivitis or an injury to the eye that looks like conjunctivitis, this medication could potentially make things worse by treating the wrong thing. Matters get even more complicated when antibiotics include steroids, as this could potentially reduce your pet's immune system's ability to fight the illness on their own. Without the proper antibiotic, it could result in a much more severe condition.

Inaccurate Dosing

Pets are prescribed an exact dose for their medications when it's given to them. This is typically based upon their size, breed, gender, and their medical condition. If an infection is very advanced, for example, your vet might prescribed a larger or more frequent dose. Giving this same size of dose to a pet who has undergone weight changes, may be pregnant, or who is just barely developing the same condition again could potentially be harmful to them.


Lastly, keep in mind that pet medications expire just like humans' do. It's important to pay attention to these expiration dates, as it typically signifies when a medication is no longer effective.

Unfortunately, the way most pets receive medications tends to differ from people. If you've been using syringes or a dropper to give your pet their medication, you should absolutely discard it once their dosing is done, and never reuse it again. This is because you may have introduced bacteria into the medication that could have grown during the time it's been sitting on the shelf. In short, you could make your pet sicker if you try to help them with old drugs.

If you think your pet has a problem, it's time to visit the vet. If you'd like, you can always bring the medication with you, and with your vet's approval, you can use that first. However, this will depend upon the type of medication and your pet's condition, as noted elsewhere in this article. For more information, reach out to a local animal hospital or professional veterinarian.