Clavamox For Cats: Overview, Dosage & Side Effects

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Clavamox for Cats Feature

Clavamox is a common antimicrobial antibiotic prescribed for a variety of bacterial infections in cats and dogs. The name Clavamox is a brand name for the generic antibiotic amoxicillin/clavulanate potassium or amoxicillin/clavulanic acid.

Clavamox For Cats Overview

Medication Type:
Tablet, Liquid
Prescription Required?:
FDA Approved?:
Life Stage:
All Life Stages
Brand Names:
Common Names:
Amoxicillin/Clavulanic Acid, Amoxicillin/Clavulanate Potassium
Available Dosages:
Tablets: 62.5mg; equivalent to 50 mg amoxicillin activity, 12.5 mg clavulanic acid as the potassium salt
Expiration Range:
10 Days (Liquid),

In this article we’ll talk about what Clavamox is, what it does, and some other useful info about dosing and safety.

What Is Clavamox?

Clavamox is what is called a potentiated penicillin antibiotic. Because of the addition of clavulanate, it can have a broader range of effect compared to plain old amoxicillin and can inhibit something called beta-lactamase, which some bacteria can produce to resist some antibiotics.

Clavamox is typically used for infections of the urinary tract, skin infections, and various infections of the soft tissues such as bite wounds.

Veterinarians also widely use Clavamox for respiratory infections as well. Because there are many different types of antibiotics out there, a veterinarian will decide which one is most appropriate to use for a particular patient.

What Does Clavamox Do For Cats?

What Clavamox does for cats

Clavamox kills bacteria associated with infections like upper respiratory infections, urinary tract infections, and soft tissue infections associated with bite wounds and other injuries.

As a bactericidal antibiotic, the role of Clavamox is to kill bacteria that are susceptible to it. In kitty cats, it is most often used for upper respiratory infections, urinary tract infections, and soft tissue infections complicating a bite wound or injury.

Clavamox works by binding directly to certain enzymes located in the cell membrane of susceptible bacteria, inhibiting the development of the cell wall and making the bacteria unstable, thus killing them.

It’s very important to note that Clavamox is not effective against viral infections, a common cause of upper respiratory conditions in cats. Therefore, it’s always important for a vet to decide if the use of an antibiotic is warranted.

Side Effects Of Clavamox For Cats

Fortunately, side effects of Clavamox in cats are typically mild and self-limiting. The most common seen is digestive upset in the form of decreased appetite, vomiting, and/or diarrhea.

As a broad-spectrum antibiotic, Clavamox can affect and alter the normal and beneficial bacteria living in the gut, which is often the cause of diarrhea if it occurs.

In many cases, ensuring Clavamox is given in close association with a meal can help to offset stomach upset. If this still occurs, discontinuing Clavamox often leads to resolution of the side effects, but should always be done under a vet’s advisement, especially if Clavamox is being used to treat an infection.

If a mild diarrhea develops, use of a probiotic at your vet’s discretion is sometimes helpful. Otherwise, mild side effects may need to be endured if a more serious infection is being successfully treated.

However, if your kitty stops eating, it is very important to tell your vet, since some cats can develop a very serious secondary liver condition from prolonged inappetence alone.

It is extremely rare but possible to see allergic reactions to Clavamox including hives, rashes, fever, and resulting abnormalities in red and white blood cell counts.

For the rare cat this might occur with, any dose could induce these effects and these effects are not dose-dependent. In other words, if your furry pal does well with a prescribed dose, and an extra dose is given accidentally, there is no higher risk for one of these allergic reactions to occur.

Clavamox For Cats Dosage

The published dosage for cats is 62.5mg per cat every 12 hours. However, it’s important to note that the dosage may differ depending on the type of infection being treated as well as a cat’s size or body weight.

Certain kitties that are either very small, like young kittens, or very large kitties suffering from obesity may be prescribed a different dose at a veterinarian’s discretion.

Dosage Forms Of Clavamox For Cats

Dosage forms of Clavamox for cats

There are a couple of different forms of Clavamox for cats. You or your veterinarian will choose between an oral suspension liquid or tablet form.

Clavamox comes in both an oral suspension liquid form as well as a tablet form. Your veterinarian may have a preference of which form to use, or may leave the dosage form up to you depending on which will be easier to administer.

If your kitty will take a pill mixed with or hidden in food or a treat, this is often easiest and involves the least amount of struggle.

However, if your furry friend is the type that will eat everything in the bowl but the tablet and leave it at the bottom, you may need to consider liquid if you are not adept at administering a pill directly into your cat’s mouth for her to swallow it.

There are both chewable and non-chewable forms of the tablet. Some kitties may take the chewable form as a treat or hidden in food, making dosing much easier.

However, because some cats can certainly be very picky about what they eat, you may find you have to administer the chewable tablet directly or consider the liquid form.

The tablets typically come in sealed blister packs to protect them, as the clavulanic acid portion is considered more susceptible to moisture.

For this reason, it’s important not to open the blister until you’re ready to give the medication. In the same vein, it is typically recommended not to split Clavamox tablets because the second tablet half will then go unused for many hours.

The liquid form typically needs to be refrigerated. It is often reconstituted with water at your vet’s practice when you receive it. If your vet prescribes two boxes, they should provide you with instructions on how to mix up the second bottle.

The instructions to do this are also typically printed on the side of the box. Because liquid Clavamox should be discarded after 10 days, it is important not to mix up a new bottle until you are ready to use it.

If a reconstituted bottle of Clavamox has been sitting out at room temperature, it may need to be discarded depending on how long it has been out, usually after a few hours. But it’s always best to give your vet clinic a call before just throwing it away.

Clavamox vs. Augmentin

Clavamox for cats

Some human-intended medications contain the same antibiotic found in Clavamox, but the dosage of Augmentin is different.

Generic medications are a popular and sometimes less-expensive alternative pet parents are interested in. Amoxicillin/clavulanate does have another brand dispensed to humans, called Augmentin.

But while they contain the same antibiotic, it is very important to understand that the dosage forms of Augmentin and Clavamox are very different, which is sometimes confusing for pet parents.

Veterinary preparations of amoxicillin/clavulanate like Clavamox have dosages expressed as the total of both the amoxicillin and clavulanate components, whereas with Augmentin and generic human forms, the dosage is typically expressed only as the amoxicillin dosage. Therefore, 125mg of Augmentin is not the same thing as 125mg of Clavamox.

For kitties, Augmentin tablets may be impractical, as the lowest dosage tablet available is double the recommended dosage for most cats (i.e. 62.5mg tablets of Augmentin do not exist). For these reasons, your veterinarian may insist on prescribing a veterinary preparation like Clavamox for your feline friend.

Concluding Thoughts On Clavamox

Clavamox is truly one of the “hardest-working” antibiotics we have available in veterinary medicine and one of the most widely-prescribed for cats. 

However, it’s really important to make sure it is only used when dispensed or prescribed by a veterinarian, and that all prescribing instructions are followed.

Indiscriminate use of any antibiotic can lead to resistant bacterial populations, which makes treating infections more difficult. Always make sure to give an antibiotic prescribed by your vet for the full number of days indicated, even if your kitty looks like he’s feeling better. 

Frequently Asked Questions

What is Clavamox used for in cats?

Clavamox is an antibiotic used to kill susceptible bacteria. It is often prescribed by veterinarians based on the types of bacterial populations most likely to be present in the affected area of the body. However, in some cases, your vet may wish to obtain a sample of the area for culture (such as a sterile urine sample or a sterile swab from an infected area of tissue) to determine exactly what antibiotic the bacteria causing the infection are susceptible to.

How Long Does Clavamox Take to Work in Cats?

For most susceptible bacterial infections, you will typically see noticeable improvement within 2-3 days of use. Full resolution for an infection depends a lot on the location and severity. This is why it’s always important to follow the prescribed directions and to finish out all of an antibiotic even if your kitty is looking much better.

If you don't feel that your kitty's signs of illness are improved at all after 3 days of use of any antibiotic, it's always a good idea to give your vet a call and let them know. It's possible your vet may make some additional recommendations.

How do you give Clavamox to a Cat?

Clavamox comes in three forms: a chewable tablet, a non-chewable tablet, and a liquid oral suspension. You and your vet should decide together which form may be best for your furry pal. 

If you think your kitty may eat the tablet (if a chewable) or by hiding it in canned or soft food or with a treat like a Pill Pocket, this is the least stressful way to give it for everybody. However, some kitties may eat around it or spit the tablet out.

The only other way to give a tablet is directly in your kitty’s mouth. Using a tool called a “pill popper” or “pilling gun” can make this method fast and easy, but still requires a certain level of skill and learning how to do it properly and safely. If you’re not familiar with directly administering a pill to a cat, having your vet or a veterinary staff member provide a demonstration may be the best way to learn how.

Many medications were not intended to be crushed or mixed with water, so before doing this to any medication to help with administration, make sure to ask your vet if this is okay.

The liquid form of Clavamox can sometimes be a good alternative for cats where pills don’t work well, as well as for very small cats and kittens. The liquid is administered directly into a cat’s mouth using an oral dosing syringe provided by your vet. 

The liquid does however tend to be messier, and you may find that your kitty either spits some out afterwards or may be more prone to drooling after. Mixing the liquid with food is less likely to be an effective way of administering it.

What Infections does Clavamox Treat?

Clavamox reaches effective concentrations in many parts of the body, making it a versatile antibiotic for many types of infections. 

The most common types of infections Clavamox is used for in cats include respiratory infections in the lungs, urinary tract infections, and infections of the skin and soft tissues, especially when wounds are involved.

The right type of antibiotic used for an illness should always be up to the discretion of your cat’s veterinarian. Clavamox is not appropriate in all cases. It’s also important to remember that Clavamox is only effective against bacteria and not against viral or fungal infections. In some cases, your vet may wish to collect a sample of the affected area for culture to verify what antibiotic will be most effective.

About Dr. Chris Vanderhoof, DVM, MPH

Dr. Chris Vanderhoof is a 2013 graduate of the Virginia-Maryland College of Veterinary Medicine (VMCVM) at Virginia Tech, where he also earned a Masters in Public Health. He completed a rotating internship with Red Bank Veterinary Hospital in New Jersey and now works as a general practitioner in the Washington D.C. area. Dr. Vanderhoof is also a copywriter specializing in the animal health field and founder of Paramount Animal Health Writing Solutions, which can be found at Dr. Vanderhoof lives in the Northern Virginia area with his family, including 3 cats.

8 thoughts on “Clavamox For Cats: Overview, Dosage & Side Effects

  1. Paige

    I have a 12 day old kitten with two infected toes. Can I give him a drop of Clavamox? Have had kitten since it was a day or two old. Brought in to local shelter with litter mates who all died. Person who brought them in claimed he found them. Person was homeless, kittens probably born to feral mom. Don’t know condition of mom.

    1. Dr. Chris Vanderhoof, DVM, MPH Post author

      Hi Paige,

      First, if you think this little kitten has two infected toes, he/she needs to have some direct veterinary assessment and care. I can only provide some limited suggestions without the ability to examine this little one. Antibiotics may help, and it sounds like you might have Clavamox on hand, but there can be a lot missed that may be needed without a veterinarian’s exam.

      It’s hard to tell if one “drop” of Clavamox would be sufficient. Antibiotic dosing is always based on weight. There is some debate about Clavamox when it comes to very small cats and kittens, but 1ml per 10lb is one commonly accepted dose. This equates to the average 10lb cat getting 62.5mg or 1ml, which is the labeled dose for Clavamox. For any cat smaller than that, we should use the weight in lb multiplied by the conversion factor of 1ml / 10lb to get an accurate volume. This might still come out to just a “drop”, like 0.05ml or something like that, but at least you’ll know it’s accurate. Many vets use actual 1 or 3ml dosing syringes in place of the droppers that Clavamox comes with, because syringes are more accurate.

      It’s true Clavamox does have a very high margin of safety, but an attending veterinarian could help with the most accurate dosing for your little kitten, as well as any other needed treatment advice.

    1. Dr. Chris Vanderhoof, DVM, MPH Post author

      Hi Lisa, this is a great question. From knowing that cats tend to be fascinated by water and are water seekers, I have found a couple methods to be helpful to encourage water intake. Increasing the number and availability of water bowls can help, as your cat may find it fascinating to seek out these new locations. Cats also are intrigued by running water, so getting a cat fountain can be another way. You can also increase water intake through food. Canned or moist foods have a high percentage of water in them, so you can temporarily increase the amount of canned food your are feeding. If you think your cat will tolerate it, some folks will also experiment with adding some water to the dry food, though this may turn off some kitties who like their crunchy food. I hope that is helpful for you and that your kitty feels better soon.

    1. Dr. Chris Vanderhoof, DVM, MPH Post author

      Hi Sheena,

      Thanks for your question, as it is a very good one. There are several types of viruses that can affect cats, but the common one that folks ask about is feline herpes virus, which is a common culprit for upper respiratory infections. Unfortunately, no antibiotics are effective against feline herpes virus, or most viruses in general. They only work against bacteria.

      This is why it is very important to have a kitty seen by a veterinarian if he or she starts to show signs of an upper respiratory infection. In many cases, especially if there is no fever, nasal discharge, or other signs of illness like lethargy or poor appetite, antibiotics are not indicated and some other supportive care can be used instead.

      By using antibiotics judiciously, we help to reduce the risk of antibiotic-resistant strains of bacteria, which unfortunately are becoming all the more common due to inappropriate antibiotic use.

  2. Lidiia

    Our kitten has a weight of 5 pounds. He has a bacterial ear infection and a stuffy nose. There is no snot and he does not sneeze. As prescribed by the doctor, we gave Clavamox 0.5 ml for 7 days. Nothing has changed in his condition. Do we need to continue giving Clavamox or does he need another medication?

    1. Mallory Crusta

      Hi there, I would advise talking to your veterinarian about your cat’s progress and asking if there are any other medications that may be able to address the underlying condition here.


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