Everything You Need To Know About Cat Antibiotics

Key Points

  • Amoxicillin is one of the most common antibiotics for cats.

  • Stopping antibiotic treatment too soon can cause bacteria to develop resistance to the drug.

  • Most antibiotics come in the form of capsules, tablets, or liquid; choose the one that's easiest to administer.

Bacterial infections profoundly affect your cat's health. Preventive measures keep bacterial infections from becoming a problem. For example, brushing your cat's teeth reduces tartar and plaque buildup to prevent bacteria from entering your cat's bloodstream. Once your cat has a bacterial infection, they need antibiotics to combat the infection.

This article provides everything you need to know about cat antibiotics and how to use them, enabling you to make well-informed decisions about your pet's treatment.

The Most Common Antibiotics for Cats

Antibiotics treat a range of bacteria, but some are more effective than others against specific types. Which one your vet chooses to prescribe depends on your cat's history, age, other medications they take, and the specific bacteria affecting your cat.

Arizona veterinarian Dr. Evan Ware wrote an article for Wedgewood Pharmacy, and North Macedonian veterinarian Dr. Ivana Crnec wrote for Veterinarians about antibiotics for cats. Ware and Crnec agree these five antibiotics are the most common ones for cats.


Amoxicillin is the most common antibiotic for cats and also very common in treating humans. Vets use it to treat ear or skin infections, respiratory or urinary infections, and gastrointestinal (GI) problems. It's effective against many bacteria, including E. coli, clostridium, and some staphylococcus species.

It comes in liquid, capsule, or tablet form. Possible side effects are vomiting, nausea, and diarrhea.


Metronidazole especially benefits cats with dental infections, periodontal disease, and gastrointestinal infections. It also treats diarrhea, inflammatory bowel disease, and protozoa parasites like giardia.

It comes in liquid, capsule, or tablet. Common side effects include GI issues like vomiting and diarrhea.


Cephalexin's most common use is treating skin infections, but it also treats infections of soft tissues, bones, urinary tract, and respiratory tract. It combats Pasteurella multocida and most staphylococci and streptococci.

It comes in liquid, capsule, tablet, or injection. Side effects are rare but can include nausea, vomiting, diarrhea, and abdominal pain.


Clindamycin is an antibiotic used to treat toxoplasmosis but also treats cats' skin, mouth, and bones. Vets use this antibiotic to treat kittens because it's well-tolerated and fast-acting. It's effective against oxygen-dependent bacteria like staphylococcus and streptococcus and non-oxygen-dependent bacteria like Clostridium perfringens.

It comes in capsules, drops, or as an injection. Side effects are rare, and a severe allergic reaction is unlikely. Vomiting, diarrhea, or decreased appetite can occur.


Enrofloxacin is a broad-spectrum antibiotic to treat skin, GI system, urinary tract, prostate, liver, and bladder issues. It also manages blood infections and wound or surgical site infections. It's a fluoroquinolone treating mainly gram-negative bacteria such as E. coli.

It comes in chewable tablets or as an emulsion for ear infections. Side effects include loss of appetite, lethargy, and nausea. There are reports of eye damage from enrofloxacin, and vets typically prescribe it only as a last resort.

Each cat's issues are unique, and they may react differently to each type of antibiotic. Tell your vet if your cat has a sensitive stomach because some medications are gentler than others. Some medications must be taken with food to combat nausea. Your vet may perform a test to identify the type of bacteria so they can choose the antibiotic most appropriate for your cat's infection.

Dr. Ware says some antibiotics prevent bacteria from reproducing; others starve the bacteria. Dr. Crnec refers to these antibiotics as bacteriostatic and bactericidal. Ware says antibiotics are important because they destroy the infected organism while keeping your cat's healthy cells intact.

Ask your vet for printed instructions for each medication, especially if there's more than one. In times of stress, it's sometimes difficult to remember even simple instructions. When filling a prescription, confirm the instructions with your pharmacist.

Why You Need a Prescription

Ware and Crnec agree over-the-counter antibiotics may not be strong enough to kill the bacteria causing your cat's infection. Some herbs have antibiotic properties but lack the strength to fight some bacteria. A prescription antibiotic from your vet is imperative.

Over-the-counter antibiotics like Neosporin are available to treat minor or surface infections. Once an infection enters the bloodstream, it becomes more serious. Other antibiotics are strong medications that must have some control over them. They also become ineffective when not administered properly.

Do not make the mistake of thinking an antibiotic fixes all problems. An antibiotic is useless if your cat is sick from anything other than a bacterial infection. Viral and other types of infections require other medications. Take your cat to the vet for a proper diagnosis and treatment plan. You want your cat to feel better, but misdiagnosis and improper treatment worsen the problem.

Some antibiotics cause side effects on some cats and interact with other medications. To avoid complications, always tell your vet what medications or supplements your cat takes.

Antibiotic Resistance

Proper use is essential to successful treatment. Neglecting to give the full dose or complete the prescribed treatment period can make the bacteria resistant to the antibiotic and more difficult to cure. Follow your vet's instructions. Even though your cat seems to feel better, ending their antibiotic regimen too soon may not kill all bacteria in their system.

The surviving bacteria can develop antimicrobial or antibiotic resistance. Think of it like a vaccination for the bacteria. The bacteria is exposed to a small amount of the medication and builds an "immunity" to it.

"Antimicrobial Resistance (AMR) occurs when bacteria, viruses, fungi and parasites change over time and no longer respond to medicines, making infections harder to treat and increasing the risk of disease spread, severe illness and death," the World Health Organization said in a November 2021 report.

An antibiotic is a specific type of antimicrobial drug that targets bacterial infections. Other antimicrobials treat fungi like candida, parasites like hookworm and tapeworm, and viruses like feline leukemia. If your cat doesn't improve after completing a treatment regimen, they may have the wrong type of antibiotic, the wrong dosage, or have a drug-resistant infection.

Administering Medication

Medicating your cat is not always an easy feat. A cat has a very sensitive sense of smell and may detect the medicine before they even taste it. To simplify this task, crush tablets or open a capsule and mix the medicine in your cat's wet food. Another tactic is to wrap a pill pocket around the tablet or capsule.

A user in a Reddit thread posted on August 15, 2023, asks if they can crush antibiotic pills. One response suggests that pill pockets make the edges smoother, especially for cut tablets.

Liquids are more difficult to disguise in food because the taste is usually stronger. As much as you hate to cause your cat discomfort and aggravation, you may have to hold them and squirt the liquid into their mouth. Aim it under their tongue or to the side and not directly at the back of their throat to avoid choking.

Always look for the path of least resistance to make the experience less traumatizing. One trick is wrapping your cat in a towel like a burrito to prevent escape and scratching. Always offer a treat after giving medication to create a positive association.

If you have difficulty giving medicine to your cat, ask your vet if the medicine comes in a different form that is easier to administer. Don't be shy about asking for tips or a demonstration on how to properly medicate your cat.

Bacteria Be Gone

Antibiotics are important in treating bacterial infections. The earlier treatment begins, the better. Since cats hide their symptoms, you may not know something is wrong until the problem has progressed.

Be aware of common health problems and how to spot them. This is the best way to prevent major illnesses. If your cat has an infection, learn about the various treatment options to bring your cat back to their best health. Learn all you can about your cat's condition and bookmark this guide as a quick reference.

Knowledge is power, and this knowledge gives you the power to make decisions that are in the best interest of your cat.

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