Amoxicillin for Dogs and Cats

What Is Amoxicillin for Dogs and Cats

Overview

Amoxicillin is a semisynthetic aminopenicillin belonging to the beta-lactam class of antibiotics. It works best when drug levels stay above the bacteria’s minimum inhibitory concentration, which is why it is described as a time-dependent antibiotic. Amoxicillin has a broader spectrum of activity than penicillin and is very effective against many common bacteria seen in dogs and cats.
In veterinary practice, amoxicillin is used alone or in combination with clavulanic acid. The combination (amoxicillin-clavulanate) greatly expands its ability to treat resistant bacteria, which is why it is one of the most frequently prescribed antibiotics in companion animals worldwide.
Explore more digestive and GI medications in our Digestive section.

What Is Amoxicillin for Dogs and Cats Used For

Amoxicillin kills bacteria by blocking their ability to build and maintain their cell wall. Without a stable cell wall, the bacteria rupture and die. Because its activity depends on maintaining therapeutic levels over time, consistent dosing is important for treatment success.

Drug Facts

Amoxicillin is a broad-spectrum, time-dependent beta-lactam antibiotic. It is often given with clavulanic acid to overcome bacterial resistance. It is widely used in dogs and cats due to its safety margin, effectiveness, and affordability.

Common Brands

Amoxi-Tabs, Amoxi-Drops

Drug Class

Beta-lactam antibiotic

Substance Classification

Not a controlled substance

Generic Status

Generic widely available

Availability

Prescription only

Amoxicillin for Dogs and Cats Dosage Forms

Amoxicillin is available in tablets, capsules, chewable tablets, and oral suspensions. Many veterinarians prefer suspensions for small pets or cats because they are easier to dose. Amoxicillin-clavulanate is commonly available in chewable tablets or liquid.

Prices vary by strength and formulation.

Tablets (20 pcs)

Oral Suspension

Typical Dosing for Amoxicillin for Dogs and Cats

Dosing depends on the type of infection, species, and whether amoxicillin is used alone or with clavulanic acid.

Dogs (UTIs and Skin Infections)

Cats (Skin Wounds and Abscesses)

General Veterinary Use

Risks and Warnings for Amoxicillin for Dogs and Cats

Amoxicillin is usually safe, but it can cause gastrointestinal side effects such as nausea, vomiting, diarrhea, or soft stools. When paired with clavulanic acid, these side effects may be more common. Rare allergic reactions, including facial swelling or hives, may occur.

GI Side Effects

• Diarrhea
• Vomiting
• Loss of appetite
• Nausea

Allergic Reactions

• Hives
• Facial swelling
• Trouble breathing (emergency)

Drug Interactions

Amoxicillin may interact with:

• Antibiotics like tetracycline
• Blood thinners
• Methotrexate

Antibiotic Resistance

Overuse can contribute to resistant bacteria, especially in chronic or recurrent infections.

Amoxicillin for Dogs and Cats Warnings and Precautions

When using amoxicillin, keep in mind the following important safety points:

• Always give the full course, even if symptoms improve.
• Give as prescribed. Do not skip doses.
• Use caution in pets with kidney disease.
• Report any allergic reactions immediately.
• Consider probiotics to reduce GI side effects.
• Keep doses spaced evenly to maintain effectiveness.

Disclaimer: This information is for educational purposes only and should not replace professional veterinary advice. Always consult your veterinarian before using or combining any medications for your pet.

Frequently Asked Questions (FAQ)

Related Medications & Supplements

Pets receiving amoxicillin for bacterial infections may require additional treatments to address underlying causes, manage symptoms, or support recovery. These closely related medications are commonly used alongside antibiotics.

• Metronidazole – antibiotic for diarrhea, colitis, and anaerobic GI infections
• Pyrantel pamoate – dewormer used when GI parasites contribute to symptoms
• Praziquantel – antiparasitic that targets tapeworms
• Nystatin – antifungal for yeast-related ear or skin infections
• Animax ointment – topical antibacterial/antifungal/steroid for localized infections
• Derma-Vet ointment – similar topical used for mixed bacterial and fungal skin issues
• Omega-3 fatty acids – anti-inflammatory support that helps skin and immune health
• Eicosaderm – high-strength omega-3 supplement used for chronic inflammatory skin issues

References

• Sainz, Á., García-Sancho, M., Villaescusa, A., Rodríguez-Franco, F., Díaz-Regañón, D., Olmeda, P. & Marks, S.L. (2024) ‘Prevalence and appropriateness of omeprazole prescription in dogs at a veterinary teaching hospital before and after the publication of the ACVIM consensus statement on the rational administration of gastrointestinal protectants’, Frontiers in Veterinary Science, 11:1352496. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC11107090/
• Gil-Vicente, L., Martín, G., Soler, C., Vila, A., Saiz, M. R. & Navarro, P.F. (2024) ‘Prospective Randomised Controlled Clinical Trial of the Long-Term Effects of Omeprazole on Healthy Dogs’, Animals, 14(8), 1168. Available at: https://www.mdpi.com/2076-2615/14/8/1168
• Handa, A., Slanzon, G.S., Ambrosini, Y.M. & Haines, J.M. (2025) ‘Effect of Omeprazole on Esophageal Microbiota in Dogs Detected Using a Minimally Invasive Sampling Method’, Journal of Veterinary Internal Medicine, 39:e70029. Available at: https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.70029
• Girod, M., Allerton, F., Gommeren, K., Tutunaru, A.C., de Marchin, J., Van Soens, I. & Ramery, E. (2016) ‘Evaluation of the effect of oral omeprazole on canine cerebrospinal fluid production: A pilot study’, The Veterinary Journal, 209:119–124. Available at: https://www.sciencedirect.com/science/article/abs/pii/S1090023315004566
• Mateus, A., Brodbelt, D.C., Barber, N. & Stärk, K.D.C. (2011) ‘Antimicrobial usage in dogs and cats in first opinion veterinary practices in the UK’, Journal of Small Animal Practice, 52(10), pp. 515-521. Available at: https://www.researchgate.net/publication/51554562_Antimicrobial_usage_in_dogs_and_cats_in_first_opinion_veterinary_practices_in_the_UK
• Garcia-Mazcorro, J.F., Dowd, S., Poulsen, J.M., Steiner, J.M. & Suchodolski, J.S. (2013) ‘Effect of the proton-pump inhibitor omeprazole on the gastrointestinal bacterial microbiota of healthy dogs’, FEMS Microbiology Ecology, 80(3), pp. 624-636. Available at: https://academic.oup.com/femsec/article/80/3/624/443262