Veterinary reviewed by: Dr. Linda Simon, MVB MRCVS

Amoxicillin for Dogs | Wag!

Veterinary reviewed by: Dr. Linda Simon, MVB MRCVS

Amoxicillin for Dogs | Wag!

Amoxicillin for dogs is an antibiotic that treats a range of bacterial infections. Available under a variety of brand names, amoxicillin is a top choice for treating skin conditions, bacterial gastroenteritis, urinary tract infections, and respiratory infections. Keep reading to find out the recommended dosage, efficacy, and frequently asked questions about amoxicillin for dogs.


The dosage strength and instructions vary depending on the brand, type of infection present, and your dog’s age and weight. Amoxicillin may be prescribed in liquid or tablet form. The recommended dose for most dogs is 5 mg per lb. Most courses of amoxicillin are administered up to twice a day for 5 to 7 days, or for 48 hours after symptoms subside completely. If stomach upset occurs, give amoxicillin with food.


Amoxicillin is one of the most effective antibiotics at treating the following conditions:

  • Infected wounds

  • Abscessed teeth

  • Respiratory tract infections

  • Bacterial gastroenteritis

  • Urinary tract infections

Amoxicillin works by preventing the growth of certain strains of bacteria, including, but not limited to:

  • E. coli

  • H. influenzae

  • Streptococci 

  • N. gonorrhea

  • Pneumococci

  • Proteus mirabilis

Amoxicillin starts working within 1 to 2 hours after the first dose. Your dog’s condition should improve within a few days. However, be sure to give your dog the full course of antibiotics according to your veterinarian’s instructions to prevent reinfection and antibiotic resistance. If symptoms persist for 5 or more days with no improvement or your pet seems to be declining, talk to your vet.

Side effects

Possible side effects of amoxicillin for dogs include:

  • Vomiting

  • Diarrhea

  • Swelling

  • Skin rash

  • Loss of appetite

  • Difficulty breathing

  • Loss of coordination

Taking amoxicillin with food typically prevents gastrointestinal symptoms. Mild side effects usually clear up within 24 hours. Serious side effects are rare.


Although amoxicillin is generally considered safe for pregnant and lactating dogs, monitor your dog closely and follow your veterinarian’s instructions.

Drug interactions

Amoxicillin may interact with the following drugs:

  • Another class of antibiotics called bacteriostatic antimicrobials

  • Immunosuppressive drugs that treat cancer (methotrexate)

  • Drugs that treat uric acid stones and gout (probenecid)

  • Blood thinners (warfarin)

Amoxicillin is generally safe to combine with other broad-spectrum antibiotics. Some combination antibiotics contain amoxicillin and clavulanic acid, which is highly effective at treating gum disease and certain skin infections. Your vet may prescribe amoxicillin in addition to other antibiotics for infections in which the bacterium is unknown or unidentified.

If your dog is taking other medications, prescribed or otherwise, let your vet know before giving the first dose.

Allergic reactions

Amoxicillin is related to penicillin and should not be given to dogs with an antibiotic allergy, amoxicillin allergy, or a penicillin allergy. The most common signs of an allergic reaction include rash and watery eyes. Less common symptoms may include:

  • Runny nose

  • Excessive scratching

  • Swelling and hives

  • Anaphylactic shock

If you notice signs of an allergic reaction, take your dog to the vet immediately.

Frequently asked questions

Do I need a prescription for amoxicillin?

Yes, amoxicillin is a prescription-only drug.

Should I refrigerate liquid amoxicillin?

Yes, you should refrigerate liquid amoxicillin.

What should I do if I miss a dose?

Administering amoxicillin around the same time each day is important, as this medication is time-dependent. Give your dog the missed dose as soon as you remember. If it’s close to time for the next dose, skip the first one and then return to your dog’s normal dosing schedule. Do not give your dog extra doses or 2 doses at once. Setting a reminder on your smartphone or calendar can help you stick to the schedule.

What should I do if my dog shows signs of an allergic reaction?

Consult your vet immediately.

Is it possible for my dog to overdose on amoxicillin?

Yes but this isn't easily done as there is a relatively high safety margin. Overdose can have serious and potentially fatal consequences. Amoxicillin overdose can cause inflammation and significant damage to the kidneys. Signs of overdose include:

  • Loss of appetite

  • Vomiting/diarrhea

  • Loss of coordination

  • Excessive panting

  • Difficulty breathing

  • Increased heart rate

  • Facial swelling

  • Hives/rashes

  • Excessive thirst

  • Excessive or discolored urine

Contact your veterinarian immediately if you notice any of these signs. Your vet may induce vomiting or administer activated charcoal to remove amoxicillin from your dog’s system. Severe cases of overdose may be treated with intravenous fluids.

Always give the recommended dosage of amoxicillin and keep medications out of your dog’s reach.

Amoxicillin Questions and Advice from Veterinary Professionals

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