Amoxicillin for Dogs and Cats
Vet-reviewed by Dr. Pippa Elliott, BVMS MRCVS ·
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.
| Condition | Notes |
|---|---|
| Skin wounds and abscesses (cats) | Highly effective against Pasteurella multocida and anaerobes. |
| Urinary tract infections (dogs) | Amoxicillin-clavulanate is a first-tier choice for bacterial UTIs. |
| Respiratory infections | Useful for bacterial upper respiratory disease. |
| Pyoderma (skin infection) | Effective for superficial and deep pyoderma when combined with clavulanate. |
| Gingivitis and dental infections (cats) | Commonly prescribed for oral bacterial infections. |
| Pre-surgical prophylaxis | Frequently used before procedures to prevent infection. |
| Bite or scratch wound prophylaxis | Used in humans and animals, sometimes preferred over clavulanate due to fewer side effects. |
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)
| Qty/Size | Price as low as | Price per unit |
|---|---|---|
| 250 mg | $9.00 | $0.45 |
| 500 mg | $12.00 | $0.60 |
Oral Suspension
| Qty/Size | Price as low as | Price per unit |
|---|---|---|
| 15 mL | $10.00 | $0.66 |
| 30 mL | $16.00 | $0.53 |
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)
| Group | Typical Dose | Notes |
|---|---|---|
| Dogs (UTI) | 12.5 mg/kg twice daily | Commonly given for 7 days. |
| Dogs with pyoderma | 10 to 14 days of amoxicillin-clavulanate | High cure rate for deep infections. |
Cats (Skin Wounds and Abscesses)
| Group | Typical Dose | Notes |
|---|---|---|
| Cats | 11 to 22 mg/kg every 12 hours | Mean effective dose was 13.8 mg/kg. |
| Cats with severe GI issues | Slurry or suspension recommended | Helps with absorption. |
General Veterinary Use
| Group | Typical Dose | Notes |
|---|---|---|
| Dogs and cats | 10 to 20 mg/kg 2 to 3 times daily | Depends on infection type and severity. |
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)
How long does amoxicillin take to work?
Most pets improve within
48 to 72 hours
, but full courses must be completed.
Can amoxicillin cause diarrhea?
Yes. GI upset is the most common side effect, especially with amoxicillin-clavulanate.
Is amoxicillin safe for cats?
Yes. It is widely used for feline wounds, abscesses, and infections.
Can I give amoxicillin with food?
Yes. Food can reduce stomach upset with no major effect on absorption.
Is amoxicillin the same as Clavamox?
No.
Clavamox = amoxicillin + clavulanic acid
, which treats more resistant bacteria.
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
Editor
The Webvet Editorial Team is a collective of seasoned pet-care journalists, veterinary content specialists, and industry editors dedicated to delivering accurate, trustworthy, and compassionate pet health information. With decades of combined experience across veterinary reporting, pet wellness education, and consumer product research, our team works closely with veterinarians and certified pet experts to ensure every article is both evidence-based and easy to understand.
Veterinarian · BVMS MRCVS
Dr. Pippa Elliott, BVMS, MRCVS, is a veterinarian with nearly 30 years of experience in companion animal practice. Dr. Elliott earned her Bachelor of Veterinary Medicine and Surgery from the University of Glasgow. She was also designated a Member of the Royal College of Veterinary Surgeons. Married with 2 grown-up kids, Dr. Elliott has a naughty Puggle named Poggle, 3 cats and a bearded dragon.
