It's a fair question: why are some pet antibiotics labeled "for dogs only" while antibiotics you get from your doctor are labeled "for human use only"? After all, antibiotics all work the same way: by working to prevent bacteria from proliferating. It shouldn't matter if the body that's got the bacteria is a dog or a human, right?
But Food Insight explains that it's not that simple, unfortunately. The main reason is that, while antibiotics target undesirable bacteria in any host animal, some antibiotics are better for humans and some are better for animals in part because of the different side effects that can occur in different species. Another issue is that while many different animals—from dogs to horses and guinea pigs to humans—can all take certain pet antibiotics, the dosage will be very different for each.
Broad spectrum antibiotics
Broad spectrum antibiotics are both pet antibiotics and human antibiotics that treat a variety of diseases caused by different bacteria. Certain infections are caused by certain bacteria, and sometimes the antibiotic can be used that works against that particular bacteria.
Broad spectrum antibiotics, though, can be used against a variety of bacteria, hence the name "broad" spectrum. For instance, doxycycline is a broad-spectrum antibiotic that can treat conditions toxoplasma, chlamydia felis and periodontal disease in both cats and dogs.
Pets vs. human antibiotics
It can be tempting to use animal antibiotics rather than a human antibiotic on yourself, because pet antibiotics are often cheaper. People are utilizing the advances in veterinary medicine by doing things like taking fish antibiotics for human conditions.
A recent article in Smithsonian talked about humans ordering fish antibiotics and taking them for their own conditions. Ornamental fish, meaning aquarium fish, can in fact take many of the same antibiotics as humans—amoxicillin, ciprofloxacin, penicillin and more—sometimes even in the same doses, according to Smithsonian. These antibiotics work by dissolving in the fish tank water, which the fish then absorb through their skin.
While fish antibiotics are much cheaper than human antibiotics, fish antibiotics are not regulated by the FDA. The FDA does approve animal drugs for pets and for animals that humans eat as food. The FDA also makes sure that things such as pesticides that are used on crops to feed animals that humans eat are also regulated.
Human use of pet antibiotics
The Smithsonian article explains that even though your pet, or your aquarium fish, might be taking the same antibiotics that you are, taking pet antibiotics is still a bad idea. The reason is that when you visit your primary care doctor for an issue, they know your health history and there's a good chance that they've run tests to determine what bacterial infection you are actually dealing with.
Antibiotics are useless against a virus and in fact could lead to bacterial resistance if you take an antibiotics for the wrong bacteria or for a virus. Unfortunately, many types of bacteria have grown resistant to penicillin_._ The article says that you can do yourself more harm by taking the wrong drug for an infection.
Furthermore, there's the side effects to consider. Each drug has its own set of side effects. For instance, taking amoxicillin (a type of antibiotic) when you have an infection caused by a virus will make your body erupt in rashes. Ciprofloxacin, which used to be a common treatment for UTIs and sinus infections, now has been shown to damage tendons, muscles, joints, nerves and the central nervous system.
The bottom line is that sometimes pet antibiotics are the same as human antibiotics. However, that doesn't mean they work the same way., or that they can be taken the same way in different species. It's best for humans to stick with human antibiotics prescribed by their doctor, who knows their health history. The same is true for pets: they should stick to cat or dog antibiotics prescribed by their vet.