Amoxicillin for Cats: This Antibiotic Works for Certain Bacterial Infections
Key takeaways:
Amoxicillin is an FDA-approved antibiotic that is used to treat a variety of bacterial infections in cats.
Amoxicillin is typically prescribed to cats as an oral suspension that must be shaken before use and stored in the fridge.
Like all antibiotics, the most common side effect of amoxicillin is stomach problems.
Table of contents
If your cat has been diagnosed with a bacterial infection, they may be prescribed an antibiotic called amoxicillin. Vets commonly prescribe amoxicillin to cats to treat a variety of bacterial infections. When used appropriately, it generally works well and is safe, with a low risk of side effects.
Amoxicillin for cats at a glance
Common brand names | Amoxicillin (Amoxi-Drops, Amoxi-Tabs, Bimox, Amoxil, Trimox, Moxatag) |
What it treats | Bacterial infections |
How it comes (forms) | Tablets, capsules, liquid suspension, and injection (typically for veterinary use only) |
Standard dosage | Based on your cat’s weight and form of medication; usually 10 mg/kg to 25 mg/kg of body weight every 12 hours |
Common side effects | Diarrhea, vomiting, loss of appetite, allergic reactions |
Cost |
What is amoxicillin for cats, and how does it work?
Amoxicillin is an antibiotic that is part of the penicillin family. It kills bacteria by weakening its cell wall, which causes the bacteria to die.
Amoxicillin only works against certain types of bacteria that lack an enzyme called beta-lactamase. Bacteria that have the beta-lactamase enzyme are resistant to amoxicillin.
Pay less for pet prescriptions with GoodRx for Pets
Save up to 80% on medications for dogs, cats, and other pets.
Amoxicillin may be combined with clavulanate potassium or clavulanic acid (Clavamox). This can increase the antibiotic’s effectiveness against bacteria with the beta-lactamase enzyme.
What is amoxicillin used for in cats?
Amoxicillin is FDA approved for a variety of bacterial infections in cats. It is most commonly prescribed to cats for bacterial infections that are:
On the skin
In the respiratory tract
In the urinary tract
It may also be prescribed for:
Dental infections
Bite wounds
Liver infections
Some gastrointestinal bacterial infections
How is amoxicillin given to cats, and what’s the standard dosage?
The amoxicillin dosage for cats is about 10 mg/kg to 25 mg/kg of body weight every 12 hours. Your veterinarian will prescribe the appropriate dosage of amoxicillin. Your cat will need to take amoxicillin for 3 to 5 days or up to a few weeks. It will depend on the type of infection your cat has as well as its weight and other conditions.
Ringworm in cats: Ringworm is a common fungal skin infection in cats. Here’s how to treat this condition as well as how to protect yourself from getting it.
Is your cat in pain? Learn to recognize the telltale signs that a cat is in pain, from drooling to hiding more than usual.
Annual vet checkups: Cats need to go to the vet at least once a year for a checkup. Don’t forget to schedule your cat’s yearly vet visit to catch health issues early.
Amoxicillin is typically prescribed to cats as a liquid form that is given by mouth. The liquid form of amoxicillin is often known by the brand name Amoxi-Drop. If your cat is prescribed the liquid form, you must shake it before use and keep it cold in a refrigerator.
Your cat’s amoxicillin may be supplied to you as powder in a bottle. Using the directions on the package, mix the powder with water. Then shake well before giving it to your cat. Store the medication in your fridge and discard any unused portions after 14 days.
Amoxicillin also comes in tablets (Amoxi-Tabs) and capsules. However, the liquid form is usually easier to give to cats. So tablets and capsules are rarely prescribed. In addition, there is an injectable form of amoxicillin. But this form is typically only for veterinary use.
Read more like this
Explore these related articles, suggested for readers like you.
Like all antibiotics, you should give amoxicillin until all the medication is gone, or as directed by your veterinarian. Even if your cat is feeling better, it is important to finish the medication as prescribed to fully eliminate the bacterial infection.
What are the common side effects of amoxicillin in cats?
In general, amoxicillin is safe and doesn’t cause many side effects. But like all antibiotics, it can cause:
Stomach upset
Vomiting
Diarrhea
Low energy
If you notice these side effects in your cat, call your veterinarian for advice as soon as possible — preferably before you give the next dose. Giving your cat the medication with food can help reduce digestive side effects.
What are the most serious risks of amoxicillin for cats?
Serious side effects of amoxicillin in cats are rare. The most severe reactions occur if your cat has an allergy to penicillin antibiotics. Signs of a penicillin allergy in cats include:
Severe vomiting and diarrhea
Swollen face
Hives (bumps all over body)
Rash on ears, forehead, or belly
Watery eyes
Fever
Anaphylaxis, which is a severe allergic reaction that can cause difficulty breathing and collapse
If you notice any of these symptoms in your cat after it takes amoxicillin, stop giving the medication and call your veterinarian or a local emergency clinic immediately. Amoxicillin should not be given to cats who have a history of allergic reactions to penicillin antibiotics.
Does amoxicillin interact with any other cat medications?
Yes, amoxicillin can interact with other medications for cats. Depending on your cat’s condition, you shouldn’t give amoxicillin at the same time as other antibiotics, especially tetracycline antibiotics. Using these antibiotics together can reduce how well amoxicillin works. Your veterinarian will help determine the best treatment for your cat.
You also shouldn’t give amoxicillin to cats that are receiving mycophenolate, a medication for certain autoimmune conditions. Amoxicillin will lower the effectiveness of mycophenolate.
Let your veterinarian know about any vitamins or supplements you are giving your cat. Even these nonprescription substances may interfere with amoxicillin or cause adverse effects.
The bottom line
Amoxicillin is a safe and effective antibiotic that can be used to treat many types of bacterial infections in cats. Give it as prescribed. And do not stop giving the medication early, even if your cat is feeling better. If your cat has any negative reactions to amoxicillin, call your veterinarian immediately for advice.
Why trust our experts?
References
Brooks, W. (2022). Amoxicillin (numerous brand names). Veterinary Partner.
Gwaltney-Brant, S. M. (2019). Antibiotic use in pets. Veterinary Partner.
Lappin, M. (2018). Management of bacterial and viral upper respiratory infections in cats. World Small Animal Veterinary Association Congress Proceedings.
Merck Veterinary Manual. (n.d.). Dosages of tetracyclines.
Plumb’s Veterinary Medication Guides. (n.d.). Amoxicillin/clavulanate.
Zoetis. (2019). Amoxi-Drop (amoxicillin for oral suspension), USP [package insert].
Zoetis. (2024). Amoxi-tabs- amoxicillin tablet, film coated [package insert]. DailyMed.
