Antibiotics for cats are essential in treating certain diseases, but they have some risks and adverse effects. In this article, we will talk about antibiotics for cats. 

Luckily, when used correctly and responsibly, the health benefits of antibiotics for cats dramatically outweigh the potential side effects. Some antibiotics are used off-label in veterinary medicine, while others are formulated and explicitly FDA-approved for pets.

If your feline has been prescribed antibiotics, keep reading to learn everything you need to know about cat antibiotics.

How do Antibiotics for Cats Work?

How do Antibiotics for Cats Work

Antibiotics for cats work by fighting off bacterial infections. To be more precise, antibiotics have two modes of action – some are bactericidal, and others are bacteriostatic.

Bactericidal antibiotics kill bacteria directly, while bacteriostatic antibiotics inhibit bacterial growth. Beta-lactams (e.g., penicillin) is an example of a bactericidal agent, while tetracycline is bacteriostatic. 

When to Use Antibiotics for Cats

You must give your cat antibiotics if your cat has a bacterial infection. The exact location of the infection does not matter, and involved tissues do not matter. 

Antibiotics are used for something as simple as an eye infection or as complicated as a bone infection. Differences in treatment include antibiotic type, duration of treatment, and mode of administration (topical versus oral). 

Benefits and Uses of Antibiotics for Cats

Preventing and fighting off bacterial infections is the main and benefit of and use of antibiotics. For example, a cat that sustained trauma to the skin can be given antibiotics to prevent wound infection. If a cat has an abscess (pocket of pus), the treatment goal would be to eliminate the current infection. 

However, antibiotics can also be used to combat parasites in conjunction with other medications. For example, antibiotics are an integral component of the treatment plan in cats with coccidiosis, giardiasis, or hemobartonellosis.  

Antibiotics can also be prescribed for cats with viral diseases such as calicivirus and feline herpesvirus). In such cases, antibiotics are not used to fight off the viruses but to treat secondary bacterial infections. 

Dr. JoAnna Pendergrass advises, “Make sure to give your cat the full course of antibiotic treatment, even if your cat starts feeling better sooner. If you stop treatment too early, all of the bacteria may not be killed. The surviving bacteria can then replicate and develop antibacterial resistance, making antibiotic treatment less effective in the future.” 

Top Antibiotics for Cats

Amoxicillin bottle

There are many cat-friendly antimicrobials. Let’s take a closer look at the most commonly used antibiotics. 

Amoxil (Amoxicillin). Amoxicillin is a broad-spectrum penicillin-type antibiotic and the most commonly prescribed antimicrobial in human and veterinary medicine. Amoxicillin is used to treat various conditions, from ear and skin issues to respiratory and urinary tract infections (UTI) and gastrointestinal problems. 

Vibramycin (Doxycycline). Doxycycline is the top antibiotic for cats with Chlamydophila felis infections exhibiting lower nasal discharge, eye irritation, and respiratory infections. This antibiotic is also used when managing certain vector-borne conditions like ehrlichiosis and heartworm disease. 

Keflex (Cephalexin). Cephalexin is a broad-range antibiotic from the cephalosporins family. It can be used to treat soft tissue and bone infections, as well as respiratory and urinary tract infections. However, the most common use of cephalexin is for skin infections (wounds and abscesses management). 

Cleocin (Clindamycin). Clindamycin is the go-to antibiotic when managing oral and dental infections. It is also an essential part of the toxoplasmosis treatment in infected cats. Clindamycin is fast-acting, and because of its efficacy and wide safety margins, it is commonly prescribed in kittens and young cats. 

Orbax (Orbifloxacin). Orbifloxacin is a synthetic broad-spectrum antibacterial agent from the fluoroquinolones family. It is primarily used in cats and is commonly prescribed for urinary tract infections (kidneys, bladder, and prostate) and skin infections (mainly post-traumatic wounds and abscesses). 

Clavamox (Amoxicillin + Clavulanic Acid). This powerful combo is closely related to penicillin, which is used for a broad spectrum of bacterial issues, including digestive, urinary tract, reproductive system, and upper respiratory infections in cats. Clavamox is also helpful in the management of skin wounds (scratches and abscesses).

Baytril (Enrofloxacin). Enrofloxacin is a broad-spectrum fluoroquinolone antibiotic that is potent against various bacteria (E.coli, Salmonella, Mycobacterium, Staphylococci, and Brucella). It is used to treat skin, bladder, respiratory, and blood infections. It is also efficient in managing wound and surgical site infections in cats. 

Flagyl (Metronidazole). Metronidazole is prescribed for the management of anaerobic infections and digestive issues. It is also the antibiotic of choice for cats with periodontal disease and dental infections. Because of its antiprotozoal activity, metronidazole can be used against certain protozoa parasites, like Giardia

Potential Side Effects and Risks of Antibiotics for Cats

As with all medications, antibiotics for cats come with various side effects. The exact adverse effects depend on the antibiotic type. Here are the potential side effects of antibiotics:

  • GI issues (vomiting, diarrhea, lack of appetite)
  • Incoordination, excitability, and seizures
  • Fever and lethargy 
  • Rashes, hives, or allergies 
  • Organ damage (kidney, liver) 
  • Infection at the injection site (for antibiotic shots)

The use of antibiotics should be carefully evaluated and closely monitored in:

  • Cats with chronic kidney and liver diseases
  • Cats receiving immunosuppressants 
  • Dehydrated and debilitated cats
  • Pregnant and lactating cats

If the antibiotics seem like they are not working and your cat’s condition does not improve, there are several possible scenarios:

  • You are using the wrong antibiotic type
  • The antibiotic is right, but the dose is too low
  • Your cat has a drug-resistant infection

Antibiotics for Cats Usage Guidelines

To decrease the risk of side effects and ensure efficient antibiotic use, it is paramount to follow the veterinarian‘s instructions regarding the antibiotic type, dose, administration frequency, and usage method. 

Dr. JoAnna Pendergrass says, “Contact your veterinarian if your cat’s condition is not improving with the antibiotic treatment. Your veterinarian may need to adjust the dosage or frequency of administration. They may also take a sample (e.g., urine sample) and perform additional testing to determine the exact type of bacteria and the most effective antibiotic against that bacteria.”

It is also important not to be misguided by antibiotic use in humans. The same antibiotic can be used in humans and cats for the same condition but in a different manner. Let’s consider UTIs as an example. 

According to the International Society for Companion Animal Infectious Diseases recommendations, the length of the antibiotic treatment for uncomplicated UTIs in cats is seven days (3 to 7 days in humans) and up to four weeks for complicated UTIs (1 to 2 weeks in humans). 

Antibiotics are available in different forms, including capsules, tablets, oral liquids, injections, and topicals (antibiotic ointments and creams). Talk to your vet about which form is easy for you to give and acceptable for your cat.

Before prescribing antibiotics, the veterinarian will consider other medications your cat might be receiving. Certain antibiotics can interact with other meds, such as:

  • Nonsteroidal anti-inflammatory drugs and steroids
  • Warfarin 
  • Tricyclic antidepressants
  • Diuretics and ACE inhibitors 
  • Immunosuppressants

Finally, we should say a word or two about natural antibiotic alternatives. Certain herbs and foods like Manuka honey, bee propolis, colloidal silver, Echinacea, and juniper berry have strong antibacterial properties. However, whether they can fully replace traditional antibiotics and resolve your cat’s infection is something you should discuss with the vet.  

Our Final Thoughts on Antibiotics for Cats

Giving your cat antibiotics

Many antibiotics can be used in cats. However, before prescribing such therapy, the vet will perform a complete physical examination and, potentially, culture and sensitivity testing to identify the bacteria and determine the most effective antibiotic type for that bacteria. 

If you suspect your cat has an infection, do not wait for the symptoms to worsen. Call your vet and schedule an appointment. In the meantime, keep in mind that the data in this article is for informative purposes only.