Amoxicillin For Cats – Usage, Dosages And Side Effects

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amoxicillin for cats

Has your cat ever been sick?

If so, your veterinarian may have prescribed antibiotics. Most people have been on antibiotics at some point, as well.

Antibiotics are a class of medication used to treat bacterial infections. These can occur as upper respiratory infections, urinary tract infections, and even skin infections.

There are a wide variety of antibiotics that might be used, and one of the most common is amoxicillin. It tends to be an inexpensive option that is very safe and generally well tolerated. Amoxicillin for cats is often one of the first drugs of choice.

Jump To:

What is amoxicillin … (1 minute read)

Can your kitty take it … (2.5 minutes read)

Forms and dosages … (1 minute read)

Best practices for amoxicillin usage … (1 minute read)

Potential side effects … (1 minute read)

What is amoxicillin?

image of the pills

Amoxicillin is an antibiotic that is related to penicillin. Amoxicillin tends to be more effective than penicillin because it lasts longer. It is more resistant to stomach acids, which would readily degrade penicillin. It is also more effective than another medication relative, ampicillin.

This is what it does:

These medications are called aminopenicillins and prevent the bacteria from making or keeping their cell wall intact. The bacteria then die. You might see it in combination products, such as Clavamox, where the medication is even more effective and long-lasting because it is mixed with a medication called clavulanic acid.

Amoxicillin is a broad-spectrum antibiotic. Bacteria come in different types, usually classified as Gram-positive or Gram-negative. Amoxicillin is effective against members of both of these categories.

Amoxicillin will only work against certain bacteria. Other infectious agents are not harmed by this medication, such as viruses and fungi.

A Brief History of Antibiotics

Alexander Fleming developed the first antibiotic in 1928. It was penicillin, which makes this an important medication. Today it isn't used as commonly. Fleming discovered penicillin growing as a mold in Fleming's laboratory. It ended up saving the lives of many soldiers in World War II after Fleming discovered that the mold killed certain bacterial cultures.

Developed for humans to take, antibiotics are used in most species of animals. These types of medicines are still saving lives today. Some, like amoxicillin, are bactericidal, which means they kill the bacteria. Others stop the bacteria from growing, making them bacteriostatic.

Can cats take amoxicillin?

You might be wondering if Fluffy can take amoxicillin, and, unless she's allergic, she can. There are specific times with the medication might be most useful.

As mentioned before, amoxicillin isn't used in cases where viruses or fungal infections are suspected. Studies have shown that amoxicillin is effective against bacteria found in the skin and mouth. As such, amoxicillin is readily prescribed for some very common maladies.


Abscesses are swollen regions of infected tissue within a pet or person. If your cat spends time outside or around other cats, she might get into a fight.

image of two felines fighting

One of the most common injuries seen in these kitties are abscesses because bacteria gets trapped under the skin from the other cat's tooth or nail. These skin infections can be very painful.

Studies have shown that amoxicillin for cats can be very effective against some of the most common bacteria found in these wounds.

Also, sometimes your cat might get a scrape that gets infected. These are also often treatable with amoxicillin. Your veterinarian might want to culture the abscess or wound. They will often start your cat on a first choice antibiotic.

Respiratory infections

image of a veterinarian examining a cat

Like you, your cat might get a respiratory infection. These are more common in the upper airways. This is like you getting a sinus infection is often more likely than bronchitis. Common signs or symptoms of an upper respiratory infection include runny eyes, sniffling, sneezing, and sometimes even coughing.

Your veterinarian will likely look for eye or nasal discharge. They will also listen to their chest for signs of pneumonia.

While some respiratory infections are caused by viruses, many are at least compounded by bacterial infections.

The bacteria typically found in your cat's airways is often sensitive to amoxicillin, making it a great choice for your kitty's illness.


Urinary tract infections can plague some cats. These are usually bacterial infections within the bladder or kidneys.

Often referred to as a UTI, they can occur in female and male cats. Your furry friend might have pain when she urinates, causing discomfort. It can decrease her willingness to use the litter box.

Your veterinarian will often collect a sample of her urine. The urine is tested to make sure that she has a UTI. They look for white blood cells and bacteria in her urine.

Amoxicillin helps

If a UTI is present, they will usually treat with an effective antibiotic. Amoxicillin for cats is often used. It can be used alone or as a combination antibiotic like Clavamox.

Forms and dosages

Amoxicillin as an antibiotic comes in several different forms and dosages. In veterinary medicine, the most common forms are liquid and pills.

The liquid amoxicillin is generally at a concentration of 100 milligrams per milliliter. The pills come in several different strengths: 100 milligrams, 250 milligrams, or 500 milligrams.

In veterinary medicine, amoxicillin can come mixed with clavulanic acid. This product is Clavamox.

Like regular amoxicillin, Clavamox also comes in liquid and pill formulations. The liquid is a 62.5 milligrams per milliliter suspension. The tablets come in a variety of sizes: 62.5 milligrams, 125 milligrams, 250 milligrams, and 375 milligrams.

You might be wondering about the amoxicillin dosage for cats.

Amoxicillin For Cats - Usage, Dosages And Side Effects 1

Studies have shown that amoxicillin alone is often effective at a dosage of eleven to twenty-two milligrams per kilogram of body weight. It is given at a frequency of two times per day. Most veterinarians treat for at least seven to ten days.

That tells you how much amoxicillin for cats, but Clavamox is even easier to dispense. Most cats take a 62.5 milligram dosage twice daily for a set amount of days.

Best Practices for Amoxicillin Usage for Cats

As with all medications, it is important to follow all the labeled directions. This includes sticking to the timetable for giving it that your veterinarian has prescribed. Liquid amoxicillin needs to be kept in the refrigerator except when you are giving it to your cat.

Amoxicillin For Cats - Usage, Dosages And Side Effects 2

If you miss a dose, give it to your cat unless it's almost time for the next dose. In that case, you can skip the missed dose. Doing so frequently can make the medication ineffective. It can also cause bacterial resistance to develop.

It is important to keep in mind that some infections may not be bacterial. It is also important to remember that amoxicillin is a medication. As such, never self-prescribe the medication to your cat, even if you are a medical doctor.

Take your cat to see your family veterinarian.

If you are concerned that your cat is not getting better or may have been misdiagnosed, go back to the veterinarian. Always remember you can go to another veterinarian for a second opinion.

Potential Side Effects of Amoxicillin for Cats

As with any medication, there is a possibility of side effects. Thankfully, amoxicillin tends to be very well tolerated by cats. Allergic reactions are not as common as with people.

The most common potential side effects are gastrointestinal problems. These include vomiting, diarrhea, or just a softer stool.

Allergic reactions do have the possibility of occurring. In cats, these can occur as hives or labored breathing.

Some cats might drool after taking the amoxicillin, especially the liquid amoxicillin. This can be a reaction, where it causes them to be nauseated, or it can just be because they don't like the taste.

Make sure to talk to your veterinarian about any signs or problems you might be seeing.

amoxicillin for cats

Can Human Amoxicillin Be Used for Cats?

As odd as it might sound, human amoxicillin can be used for cats. If your veterinarian doesn't have it in stock, they may write a prescription. They may have you get it filled at a human pharmacy like Walgreens. It's the exact same medication.

If your cat is prescribed Clavamox, you might be familiar with it as Augmentin. That is the human form of amoxicillin with clavulanic acid.

In Conclusion

If your cat is sick or not acting like herself, a trip to your family veterinarian is recommended.

They may diagnose a bacterial infection, and if so, amoxicillin might be used. This antibiotic has been around for a long time and is very effective against many types of bacteria.

There are also other formulations, such as Clavamox. This has another medication added to the amoxicillin. It makes it even more potent and long-lasting.

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