# Amoxicillin Clavulanate Potassium for Pets Amoxicillin clavulanate potassium is a prescription combination antibiotic that treats bacterial infections in dogs and cats. It pairs amoxicillin, a penicillin-type antibiotic that kills bacteria by disrupting their cell walls, with clavulanate potassium, a beta-lactamase inhibitor that blocks the bacterial enzymes which would otherwise destroy amoxicillin. The result is a broader-spectrum drug than amoxicillin alone, and it is one of the most frequently prescribed antibiotics in small animal practice [1]. It is used for skin infections, urinary tract infections, dental and oral infections, respiratory infections, and wound infections in dogs and cats. It is not effective against viral infections, and it does not treat parasites or fungal disease. This article covers what amoxicillin clavulanate potassium does, how the two ingredients work together, which infections it is labeled for, what side effects owners should watch for, how to give it safely at home, and when to call a veterinarian. **This article is educational and is not a substitute for veterinary diagnosis or treatment.** ## At a Glance | Feature | Detail | |--|--| | Active ingredients | Amoxicillin (a penicillin antibiotic) plus clavulanate potassium (a beta-lactamase inhibitor) | | Common brand names | Clavamox, Augmentin (human product) | | Species | Dogs and cats | | How it is given | By mouth as a chewable or tablet, or by injection in a hospital setting | | Typical ratio | 4:1 amoxicillin to clavulanate in veterinary products | | How fast it works | Improvement in clinical signs is usually seen within a few days, though the full course must be completed | | How long it lasts | Dosing is typically every 12 hours, depending on the label and the condition | | Prescription status | Prescription only in the United States | | Main side effects | Vomiting, diarrhea, and rarely allergic reactions | | Give with food? | Yes, giving it with food reduces stomach upset | ## What Amoxicillin Clavulanate Potassium Is

Amoxicillin clavulanate potassium is a fixed-dose combination antibiotic. The amoxicillin component is a beta-lactam antibiotic that interferes with the construction of the bacterial cell wall. Bacteria that produce beta-lactamase enzymes can break down amoxicillin before it reaches its target, which is a common resistance mechanism. Clavulanate potassium is itself a beta-lactam molecule, but a weak one. Its job is to bind and inactivate beta-lactamase enzymes so that amoxicillin survives long enough to work [2]. This makes clavulanate a "suicide inhibitor," meaning it sacrifices itself to protect the amoxicillin. The ratio of the two drugs matters. Veterinary formulations commonly use a 4:1 ratio of amoxicillin to clavulanate, and this ratio is the basis for approved label dosing in animals [3]. A 4:1 product is not interchangeable with a human product that uses a different ratio, and human tablets are not dosed for pets. The ratio is set so that enough clavulanate is present to neutralize the beta-lactamase enzymes produced by target bacteria while enough amoxicillin remains to kill them. Amoxicillin clavulanate potassium is a broad-spectrum antibiotic in the sense that it covers more organisms than plain amoxicillin. It is active against many gram-positive bacteria, including Staphylococcus species, and against a range of gram-negative and anaerobic bacteria. It is a mainstay of empirical treatment for common infections in dogs and cats, which is why it appears so often in veterinary prescriptions [1]. ## How the Combination Works ### Amoxicillin: The Killer Amoxicillin stops bacteria from building a proper cell wall. Without a functional wall, the bacteria cannot maintain their internal pressure and they rupture. This is a bactericidal effect, meaning it kills bacteria rather than just stopping their growth. Amoxicillin works best against actively dividing bacteria, which is one reason the drug must be given on a consistent schedule. ### Clavulanate: The Protector Many bacteria defend themselves by producing beta-lactamase enzymes that chemically destroy amoxicillin. Clavulanate potassium binds these enzymes and shuts them down. Once the enzymes are neutralized, amoxicillin can reach the bacterial cell wall and do its job. Without clavulanate, a beta-lactamase-producing infection would simply ignore the amoxicillin. This protective effect is why the combination extends amoxicillin's activity against beta-lactamase-producing bacteria. In a study of subgingival bacteria from dogs with periodontal disease, no resistance was found to amoxicillin clavulanate among the Porphyromonas isolates tested, even though some isolates were resistant to ampicillin and penicillin alone [4]. That difference reflects the value of the clavulanate component. ### Why the Ratio Matters The 4:1 ratio is not arbitrary. Too little clavulanate and the beta-lactamase enzymes overwhelm the inhibitor. Too much clavulanate relative to amoxicillin and the antibiotic effect is diluted. Veterinary products are formulated and labeled at a specific ratio, and the dosing instructions on the label assume that ratio [3]. This is one reason owners should never substitute a human tablet for a veterinary product, even if the milligram strength looks similar. ## What Amoxicillin Clavulanate Potassium Is Used For Amoxicillin clavulanate potassium is prescribed for bacterial infections in dogs and cats. The most common categories are skin, urinary, dental, and respiratory infections, along with wound and soft tissue infections. ### Skin Infections Bacterial skin infections, also called pyoderma, are among the most frequent reasons this drug is prescribed. Staphylococcus pseudintermedius is the primary bacterial agent associated with canine pyoderma [5]. In a meta-analysis of dogs with pyoderma in Asia, isolates of methicillin-susceptible S. pseudintermedius had the lowest resistance to amoxicillin clavulanate and oxacillin, while methicillin-resistant strains showed broader resistance [5]. This pattern supports the use of amoxicillin clavulanate for susceptible skin infections while highlighting why culture and susceptibility testing matter when a dog does not improve. Otitis externa, or infection of the outer ear canal, is another skin-related condition where this drug may be used. In a study of canine otitis externa, S. pseudintermedius was the most common isolate at 41 percent, followed by Staphylococcus aureus at 23 percent and Pseudomonas aeruginosa at 19 percent [6]. Pseudomonas isolates showed high resistance to beta-lactams, including 93 percent resistance to amoxicillin clavulanate, so ear infections caused by this organism are unlikely to respond [6]. ### Urinary Tract Infections Amoxicillin clavulanate is used for urinary tract infections, particularly those caused by Escherichia coli. A study using a hollow-fiber infection model found that amoxicillin clavulanate produced sustained bactericidal activity in urinary-like drug exposures without resistance emerging, while plasma-like exposures rapidly selected for resistant subpopulations [7]. This helps explain why the drug works well for urinary tract infections even though its success against E. coli in other body sites is more limited [7]. The high concentrations of clavulanate achieved in urine appear to contribute direct antibacterial activity [7]. ### Dental and Oral Infections Periodontal disease is extremely common in dogs, and amoxicillin clavulanate is one of the antibiotics used when bacterial infection of the gums and tooth-supporting structures requires treatment. In a study of subgingival bacteria from dogs with periodontitis, resistance to amoxicillin clavulanate was found in a portion of isolates, though Porphyromonas species showed no resistance to the combination [4]. Antibiotics for dental disease are typically paired with professional dental cleaning, because medication alone does not remove plaque and tartar. ### Respiratory Infections Amoxicillin clavulanate is frequently prescribed for respiratory infections in dogs. In a case series of 13 dogs with pneumonia associated with Mycoplasma cynos, amoxicillin clavulanate was among the antibiotics frequently prescribed for two weeks or longer [8]. Twelve of the 13 dogs survived [8]. This is a reminder that respiratory infections can have multiple causes and that response depends on the specific organism involved. ### Other Uses The drug is also used for wound infections, abscesses, and soft tissue infections. In a case report of a dog with Brucella canis myocarditis, amoxicillin clavulanate was prescribed at discharge before the underlying diagnosis was identified, after which therapy was switched [9]. That case illustrates a broader point: amoxicillin clavulanate is a reasonable first choice for many common infections, but it is not the right drug for every organism, and a diagnosis that does not respond should prompt a change in plan. ## What Amoxicillin Clavulanate Potassium Does Not Cover Amoxicillin clavulanate potassium does not treat viral infections such as parvovirus, distemper, or feline upper respiratory viruses. It does not treat fungal infections or yeast infections. It does not treat parasites. It does not reliably cover bacteria that produce extended-spectrum beta-lactamases or methicillin-resistant staphylococci, which are common in some referral populations [5]. Resistance is not rare. In a study of E. coli isolated from canine pyometra cases, all isolates were resistant to amoxicillin clavulanate [10]. In a study of canine otitis externa, Pseudomonas aeruginosa isolates showed 93 percent resistance to amoxicillin clavulanate [6]. In a study of subgingival bacteria from dogs with periodontal disease, resistance to amoxicillin clavulanate was found in a portion of isolates [4]. These findings do not mean the drug is a poor choice. They mean that culture and susceptibility testing are valuable when an infection is severe, recurrent, or not responding to initial treatment. ## How Amoxicillin Clavulanate Potassium Is Given Amoxicillin clavulanate potassium is given by mouth, usually every 12 hours. The exact dose depends on the animal's weight, the condition being treated, and the product label. In some hospital settings, an injectable form is given intravenously [1][11]. Give the medication with food. Food reduces the chance of stomach upset and helps with absorption. If your pet is a picky eater, ask your veterinarian whether the medication can be hidden in a small amount of food or given as a flavored chewable product. Complete the full course even if your pet seems better after a few days. Stopping early can allow surviving bacteria to regrow and can promote resistance. If your veterinarian prescribed a specific number of days, follow that exactly. Do not use human tablets meant for people. Human amoxicillin clavulanate products may use different ratios, different strengths, and different formulations that are not dosed for animals. Giving a human tablet can underdose or overdose your pet. Use only the veterinary product dispensed by your veterinarian. Do not save leftover antibiotics for a future illness. Do not give your pet's medication to another animal in the household. Do not use a leftover supply without veterinary guidance. ## Labeled Dosing by Species The table below reflects doses as stated on approved veterinary product labels. Do not adjust these doses on your own. Your veterinarian will confirm the correct dose for your pet. | Species | Labeled dose (per approved label) | Frequency | Notes | |--|--|--|--| | Dog | 6.25 mg/lb (13.75 mg/kg) body weight | Every 12 hours | Veterinary 4:1 formulation, given with food | | Cat | 62.5 mg per cat (typical small-cat label dose) | Every 12 hours | Veterinary 4:1 formulation, given with food | Doses vary by product and by the condition being treated. Some labels provide a range rather than a single number, and some conditions require a different schedule. Always follow the specific instructions on the label your veterinarian dispenses. In cattle, an approved 4:1 amoxicillin trihydrate and clavulanic acid product is dosed at 8.75 mg/kg body weight intramuscularly [3]. That product and route are for cattle and are not used in dogs or cats. It is included here only to show that the 4:1 ratio appears across species and that label doses differ by species and formulation [3]. ## Side Effects of Amoxicillin Clavulanate Potassium ### Vomiting and Diarrhea The most common side effects are vomiting and diarrhea. In cats, amoxicillin clavulanate is known to cause diarrhea, and a study of healthy cats given the drug for seven days documented an antibiotic-induced shift in fecal microbiota along with changes in fecal bile acid metabolism [12]. The probiotic Enterococcus lactis strain SF68 has been shown to lessen amoxicillin clavulanate-associated diarrhea in cats, and the same study found that the probiotic sped recovery of the feline dysbiosis index [12]. In calves, a five-day course of amoxicillin clavulanate reduced fecal bacterial diversity and decreased the relative abundance of Lachnospiraceae, a bacterial family considered beneficial for host health, while increasing Pseudomonadota, which includes opportunistic pathogens [13]. That study was in calves, not dogs or cats, but it illustrates the general principle that this antibiotic affects the gut microbiome. If your pet vomits or has diarrhea after starting the medication, call your veterinarian. Do not stop the antibiotic on your own unless your veterinarian tells you to. In many cases, giving the medication with a fuller meal or splitting the dose differently can help. ### Allergic Reactions Allergic reactions to amoxicillin clavulanate are uncommon but can occur. In a study of 431 dogs that received intravenous amoxicillin clavulanate, 20 were suspected of having an immediate allergic reaction, and after exclusions, 11 dogs had signs classified as grade 1 [1]. Facial edema and facial pruritus were the most common features, and the frequency of immediate reactions was 3.3 percent [1]. The authors noted that reactions were clinically mild and primarily cutaneous [1]. A separate study of 1,672 dogs and cats that received a new intravenous formulation of amoxicillin clavulanate found an apparent type I hypersensitivity reaction in 11 dogs and no cats, for an incidence of 0.81 percent in dogs [11]. Dermatologic signs were recorded in all 11 cases, and some dogs also showed cardiovascular or gastrointestinal signs [11]. All cases survived [11]. Signs of an allergic reaction include facial swelling, hives, itching, vomiting, difficulty breathing, and collapse. If you see facial swelling, hives, or trouble breathing, stop the medication and contact your veterinarian or an emergency clinic immediately. ### Liver Effects Clavulanic acid has been associated with drug-induced liver injury, and a laboratory study using human-derived cell lines found that cytochrome P450 enzymes can metabolize clavulanic acid in ways that contribute to cytotoxicity [2]. This is a laboratory finding, not a clinical report in dogs or cats, and it does not change the risk-benefit calculation for most pets. It does mean that pets with pre-existing liver disease should be monitored, and any signs of jaundice, loss of appetite, or lethargy during treatment should be reported to your veterinarian. ### Other Effects Less common effects include reduced appetite, lethargy, and changes in behavior. If your pet seems unwell in any way during treatment, contact your veterinarian. ## Which Pets Should Not Receive Amoxicillin Clavulanate Potassium Amoxicillin clavulanate potassium should not be given to pets with a known allergy to penicillins or cephalosporins. Tell your veterinarian about any previous reaction to an antibiotic, even if it was mild. Use with caution in pets with liver disease or kidney disease. Dose adjustments may be needed, and monitoring may be recommended. Amoxicillin clavulanate is generally avoided in rabbits, guinea pigs, hamsters, and other small herbivores because it can disrupt their gut flora severely. If you have a small mammal, ask your veterinarian about a different antibiotic. Pregnant and nursing animals should receive the drug only when the veterinarian determines that the benefit outweighs the risk. ## Drug Interactions Amoxicillin clavulanate can interact with other medications. Tell your veterinarian about everything your pet is taking, including prescription drugs, over-the-counter products, and supplements. Some interactions to discuss with your veterinarian include: - Other antibiotics, especially bacteriostatic drugs that may reduce the effectiveness of penicillins - Methotrexate, which may have increased toxicity - Allopurinol, which may increase the risk of rash - Probenecid, which can increase amoxicillin blood levels - Warfarin and other anticoagulants, which may have altered effects Do not start or stop any medication without telling your veterinarian. ## How Amoxicillin Clavulanate Compares With Other Antibiotics Amoxicillin clavulanate is often a first-choice antibiotic for skin, urinary, dental, and soft tissue infections because of its broad spectrum and its activity against beta-lactamase-producing bacteria. It is available as a flavored chewable and as a tablet, which makes it easier to give than some alternatives. Other common veterinary antibiotics include: - Cephalexin, another beta-lactam antibiotic often used for skin infections - Clindamycin, which is used for dental and soft tissue infections and has good anaerobic coverage - Doxycycline, which is used for respiratory infections and tick-borne diseases - Enrofloxacin and other fluoroquinolones, which are used for serious gram-negative infections - Metronidazole, which is used for anaerobic and protozoal infections The choice depends on the organism, the site of infection, the pet's history, and whether culture results are available. In a study of canine pyometra, amoxicillin clavulanate was the most commonly prescribed inappropriate antibiotic, meaning the bacteria were not susceptible to it [14]. That finding does not mean the drug is a poor choice in general. It means that empirical prescribing without culture can miss. ## Questions to Ask Your Veterinarian Before starting amoxicillin clavulanate potassium, ask: 1. What infection are we treating, and how was it diagnosed? 2. What is the exact dose, and how many times per day should I give it? 3. How many days should I give the medication? 4. Should I give it with food, and is there a specific way to give it? 5. What side effects should I watch for? 6. What should I do if my pet vomits or has diarrhea? 7. When should I bring my pet back for a recheck? 8. What should I do if my pet seems better before the course is finished? Write down the answers. If you are unsure about anything, call the clinic before you give the first dose. ## Owner Administration Tips Give the medication at the same times each day. A 12-hour schedule works well for most pets. If you work outside the home, plan the doses around your schedule. Give the medication with food. A small meal or a treat right before the dose can reduce stomach upset. If your pet refuses the medication, do not force it. Ask your veterinarian about a flavored chewable or a different formulation. If you miss a dose, give it as soon as you remember, unless it is almost time for the next dose. Do not double up. Keep a written log of doses given. This helps you stay on schedule and helps your veterinarian if a problem arises. Store the medication as directed on the label. Most veterinary products should be kept at room temperature, away from moisture and heat. Do not store antibiotics in the bathroom. Wash your hands after giving the medication. Some people are allergic to penicillins and can react to contact with the drug. ## Limitations and When to Contact a Veterinarian This article is educational. Individual cases need a veterinarian who can examine your pet, review the history, and decide on the right treatment. Contact your veterinarian or an emergency clinic if you see any of the following: - Facial swelling, hives, or itching after a dose - Difficulty breathing, collapse, or weakness - Repeated vomiting or severe diarrhea - Blood in the stool or vomit - Yellowing of the gums, skin, or eyes - Loss of appetite that lasts more than a day - Lethargy or behavior changes - No improvement after three to four days of treatment - Worsening of the original signs - Any new sign that worries you Do not wait to see if a reaction resolves on its own. Allergic reactions can progress quickly, and early treatment is safer. ## Frequently Asked Questions ### What is amoxicillin clavulanate potassium used for in pets? It treats bacterial infections in dogs and cats, including skin infections, urinary tract infections, dental infections, respiratory infections, and wound infections. It is a prescription antibiotic and is not effective against viruses, fungi, or parasites. ### How long does it take to work? Most pets show improvement within a few days, but the full course must be completed. If your pet is not improving after three to four days, call your veterinarian. ### Can I give my pet human amoxicillin clavulanate? No. Human products may use different ratios and strengths that are not dosed for animals. Use only the veterinary product dispensed by your veterinarian. ### Should I give it with food? Yes. Giving it with food reduces the chance of stomach upset and helps with absorption. ### What are the most common side effects? Vomiting and diarrhea are the most common. Allergic reactions are rare but can occur, and they usually involve facial swelling or itching. ### What should I do if my pet vomits after a dose? Call your veterinarian. Do not stop the medication on your own unless your veterinarian tells you to. In many cases, giving the medication with a fuller meal can help. ### Can I stop the antibiotic once my pet feels better? No. Complete the full course as prescribed. Stopping early can allow the infection to return and can promote antibiotic resistance. ### Is amoxicillin clavulanate safe for cats? Yes, it is approved for use in cats when prescribed by a veterinarian. Cats may be more prone to diarrhea during treatment, and a probiotic may help. ## Related Articles - [Clavamox Amoxicillin-Clavulanate: Feline Respiratory and Skin Infection Dose](/knowledge/veterinary-medicine/calculators-clinical-tools/clavamox-amoxicillin-clavulanate-feline-respiratory-and-skin-infection-dose) - [Potassium Bromide Epilepsy Dose: Refractory Seizure Add-On Protocol](/knowledge/veterinary-medicine/calculators-clinical-tools/potassium-bromide-epilepsy-dose-refractory-seizure-add-on-protocol) - [Prescription Kidney Diet for Cats: Low Phosphorus Protein and Potassium](/knowledge/veterinary-medicine/nutrition/prescription-kidney-diet-for-cats-low-phosphorus-protein-and-potassium) - [Amoxicillin Dog Cat Dose: Broad-Spectrum Antibiotic Weight-Based Guide](/knowledge/veterinary-medicine/calculators-clinical-tools/amoxicillin-dog-cat-dose-broad-spectrum-antibiotic-weight-based-guide) - [Drug Interactions with Anticonvulsant Medications in Veterinary Patients: Phenobarbital, Potassium Bromide, and Levetiracetam](/knowledge/veterinary-medicine/clinical-pharmacology/drug-interactions-anticonvulsant-medications-veterinary) - [Pet Training Guide W101](/knowledge/veterinary-medicine/behavior/pet-training-guide-w101) - [Amoxicillin vs Amoxicillin-Clavulanate: Key Differences](/knowledge/veterinary-medicine/clinical-pharmacology/amoxicillin-vs-amoxicillin-clavulanate-key-differences) ## Sources 1. [Clinical characteristics of immediate allergic adverse reactions to intravenous amoxicillin-clavulanic acid in conscious dogs.](https://pubmed.ncbi.nlm.nih.gov/41450216/) 2. [Contribution of cytochrome P450-mediated metabolism to clavulanic acid-induced cytotoxicity in TK6-derived cytochrome P450-overexpressing cell lines.](https://pubmed.ncbi.nlm.nih.gov/42449129/) 3. [Distribution of amoxicillin and clavulanic acid in the uterus of healthy and metritic cows after intramuscular injection.](https://pubmed.ncbi.nlm.nih.gov/41937054/) 4. [Antimicrobial susceptibility of Porphyromonas spp. isolated from dogs with periodontal disease in South Korea.](https://pubmed.ncbi.nlm.nih.gov/41293225/) 5. [Prevalence and antibiotic resistance profile of Staphylococcus pseudintermedius in pyodermic dogs in Asia: a systematic review and meta-analysis.](https://pubmed.ncbi.nlm.nih.gov/42065810/) 6. [Bacterial Agents and Antimicrobial-Resistance Patterns in Canine Otitis Externa.](https://pubmed.ncbi.nlm.nih.gov/41302025/) 7. [Molecular pharmacodynamics of amoxicillin-clavulanic acid for urinary tract infections caused by Escherichia coli.](https://pubmed.ncbi.nlm.nih.gov/42288477/) 8. [Mycoplasma cynos-Associated Canine Infectious Respiratory Disease Complex Pneumonia in 13 Dogs.](https://pubmed.ncbi.nlm.nih.gov/41178398/) 9. [Myocarditis in a Dog Positive for Brucella canis.](https://pubmed.ncbi.nlm.nih.gov/41190687/) 10. [Characterization of Phylogroups, Virulence Factors and Antimicrobial Resistance in Canine Pyometra-associated Escherichia coli.](https://pubmed.ncbi.nlm.nih.gov/42579313/) 11. [Retrospective Determination of the Incidence of Apparent Type I Hypersensitivity Reaction to Intravenous Amoxicillin-Clavulanate in Dogs and Cats.](https://pubmed.ncbi.nlm.nih.gov/41582857/) 12. [Oral administration of Enterococcus lactis strain SF68 speeds the recovery of amoxicillin-clavulanate-induced dysbiosis in cats.](https://pubmed.ncbi.nlm.nih.gov/41923274/) 13. [Changes in fecal microbiota after therapeutic exposure to amoxicillin-clavulanic acid in veal calves receiving multiple antibiotics.](https://pubmed.ncbi.nlm.nih.gov/41211966/) 14. [Sepsis and elevated creatinine predict poor outcomes in uncomplicated canine pyometra, and empirically prescribed antibiotics do not match bacterial susceptibility or improve survival.](https://pubmed.ncbi.nlm.nih.gov/42716105/)