Amoxicillin/Clavulanate for Dogs and Cats

Medically Reviewed by Joshua Conrad, PharmD on September 19, 2024
Written by Kathleen Claussen, DVM
6 min read

Amoxicillin/clavulanate (brand names: Augmentin, Clavacillin, Clavamox) is a medicine used in pets to treat skin infections, gum disease, and soft tissue infections such as abscesses and wounds. 

This drug contains amoxicillin and clavulanate. The amoxicillin kills the bacteria. The clavulanate helps the amoxicillin work better by blocking the bacteria’s effort to stop it. Amoxicillin/clavulanate doesn’t work for all types of infections. It only treats those caused by certain gram-negative bacteria and anaerobic bacteria (bacteria that grow without the need for oxygen).

Amoxicillin/clavulanate is FDA-approved to treat:

  • Periodontal (gum) disease in dogs
  • Skin infections in dogs and cats
  • Soft tissue infections (wounds, abscesses) in dogs and cats
  • Urinary tract infections in cats

Amoxicillin/clavulanate can also be used off-label or extra-label to treat dogs and cats for respiratory tract infections (infections of their lungs, sinuses, and airways) caused by certain bacteria. Extra-label or off-label means your vet prescribed a drug that’s not FDA-approval for that use, but there’s evidence it’s safe and effective.

Amoxicillin/clavulanate is available as a prescription from your veterinarian, or with a veterinary prescription from an online pet pharmacy or human pharmacy. It comes in various dosages as a tablet, chewable tablet, or liquid you take by mouth. Contact your veterinary compounding pharmacy for other dosing options. 

It's best to use an amoxicillin/clavulanate product made just for animals, when possible. Its versions meant for people have different amounts of amoxicillin and clavulanate compared to the pet versions. This can make it difficult to give your pet the correct dose if you use the version meant for people. 

Amoxicillin/clavulanate is a tablet, chewable tablet, or liquid taken by mouth. It’s usually given every 12 hours for as long as it’s prescribed. If your vet prescribed the pork liver-flavored chewable tablets, keep them out of reach of your pets and children to prevent accidental taking or overdose.

Amoxicillin/clavulanate may be given with or without food. If your pet’s stomach gets upset after taking it on an empty stomach, try the medicine with a small amount of food or a treat. If your pet takes the liquid form, shake it well and measure it using the dosing dropper or syringe that comes with it. Slowly put the liquid into your pet’s mouth so they get all of the dose.

Always follow your vet’s directions for giving medicine to your pet. Tell them about any medicines, vitamins, supplements, or herbal therapies your pet takes. Talk to your vet before stopping any of your pet’s medicines. 

They include:

  • It can help treat many common infections in dogs and cats.
  • It comes in different forms so it’s easier for your pet to take.
  • It starts to work in 1 to 2 hours.
  • It’s FDA-approved for use in dogs and cats.

You and your vet should monitor your pet for improvement, as well as side effects of the medicine. Before giving your pet amoxicillin/clavulanate, your vet may do a test to make sure they get the best antibiotic for their condition. This is called a bacterial culture and sensitivity test.

Yes. Don’t use it if your pet is allergic to it or other penicillin-type antibiotics. Use it with caution if your pet is pregnant or nursing. Never use amoxicillin/clavulanate in rabbits, guinea pigs, chinchillas, gerbils, hamsters, or prairie dogs because it can make them have serious side effects and sometimes die.

Side effects are usually related to the gastrointestinal system (stomach and intestines). They may include:

  • Vomiting
  • Decreased or no appetite, especially in cats
  • Loose stool or severe diarrhea

If your pet has side effects, stop the medicine and contact your veterinarian. They’ll discuss treatment options, depending on what side effects your pet has. They may recommend switching to a different antibiotic, or they may suggest managing their symptoms and staying on the medicine. Your vet may recommend starting a probiotic to help change your pet’s gut flora. That's the good bacteria that live in your pet’s intestines.

While there’s a low risk of severe side effects, too much amoxicillin/clavulanate can cause serious problems. Your pet’s nervous system and liver can be harmed. If your cat stops eating completely, it could be a sign of a serious problem. Keep pork liver-flavored chewable tablets out of the reach of pets and children. 

If you suspect your pet is having a serious side effect or they took too much, call your vet clinic right away. If it’s outside regular office hours, contact a local emergency veterinary hospital or an animal poison control center. Be aware you may have higher fees for emergency care. You can reach the ASPCA Animal Poison Control Center at 888-426-4435 or the Pet Poison Helpline at 855-764-7661.

Using more than one medicine at a time with your pet can change how those medicines work. It can also raise your pet’s risk of  serious side effects. Tell your vet about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements your pet takes.

Before giving your pet amoxicillin/clavulanate, tell your vet if they also take:

Other antibiotics. When other antibiotics, such as chloramphenicol, erythromycin, sulfonamides, or tetracyclines, are used with amoxicillin/clavulanate, they can work against each other. They may not be very effective, or your pet may have side effects or a longer infection. 

Methotrexate. Methotrexate is a medicine used to treat cancer. It affects how well your pet’s immune system works. When methotrexate and amoxicillin/clavulanate are used at the same time, the methotrexate can reach toxic levels in your cat or dog and cause serious side effects.

Warfarin. Warfarin helps thin your pet’s blood and prevent blood clots. They’re more likely to have serious bleeding when this medicine is used with amoxicillin/clavulanate.

This may not be a complete list of medicines that can interact with amoxicillin/ clavulanate. Always check with your veterinarian.

Keep amoxicillin/clavulanate out of the reach of children. Wash your hands after giving it to your pet. Don’t handle amoxicillin/clavulanate if you’re allergic to it.

The chewable amoxicillin/clavulanate smells and tastes really good to many dogs and cats. They may try to chew their way into the package if it’s left where they can get to it. These tablets should be stored in the original prescription package. To prevent accidental taking, store the package in a secure location out of the reach of your pet. If you suspect your pet took more amoxicillin/clavulanate than prescribed, call your vet or veterinary emergency clinic right away.

If you miss a dose of your pet’s medication, you can still give them that dose if it’s close to the original scheduled time. If it’s closer to the next dosing time, skip the missed dose completely and give the next dose at the correct time. Don’t double the dose, but make sure your pet finishes all medicine as prescribed. 

Amoxicillin/clavulanate tablets and chewable tablets should be protected from light and stored at room temperature. They should be stored in the original packaging until you’re ready to give a dose to your pet, because these tablets don’t do well if they get moist. If you have to split a tablet, place the remaining half-tablet back into the original package. Then place it into a sealed container until it’s time for the next dose. This medicine’s liquid form should be stored in your fridge for up to 10 days. Then, throw away what’s left.