Clavamox — the brand name most dog owners recognize — is one of the most frequently prescribed antibiotics in veterinary medicine in the United States. It is not a single drug. It is two drugs working in tandem: amoxicillin, a broad-spectrum penicillin-type antibiotic, and clavulanic acid, a compound that stops certain bacteria from disabling the amoxicillin before it can work. The combination is FDA-approved for dogs under NADA 055-099 (tablets) and NADA 055-101 (drops), manufactured by Zoetis. This guide covers what vets actually prescribe it for, the dosing math, what to watch for, and the questions most dog owners don’t think to ask until something goes wrong.
These answers address the questions that come up most often — before the prescription is filled and after it starts. Read these before anything else.
- 1 What exactly is Clavamox, and why does my dog need it instead of plain amoxicillin? Clavamox combines amoxicillin with clavulanic acid — and that second ingredient is what makes it meaningfully different. Many bacteria produce an enzyme called beta-lactamase that breaks down amoxicillin before it can kill them, effectively making the infection amoxicillin-resistant. Clavulanic acid blocks that enzyme, so the amoxicillin can do its job against a much wider range of bacterial species. Your vet chose the combination specifically because your dog’s infection is likely caused by bacteria that would defeat plain amoxicillin alone.
- 2 What is the correct dose of Clavamox for dogs? The FDA-approved dose is 6.25 mg per pound of body weight, given twice daily (every 12 hours) with food. For the liquid drops, that works out to 1 mL per 10 pounds twice daily. Tablet strengths come in 62.5 mg, 125 mg, 250 mg, and 375 mg — all maintaining the same 4:1 amoxicillin-to-clavulanate ratio. Your veterinarian calculates the appropriate tablet size for your dog’s weight. Do not adjust the dose on your own, even if your dog seems better before the course ends.
- 3 Can I stop giving Clavamox once my dog looks better? No — and this is one of the most important things to understand about any antibiotic. When your dog looks better, the visible infection has retreated, but a smaller population of bacteria may still be present. These surviving bacteria are often the ones with the most natural resistance to the drug. Stopping early allows them to repopulate — and the next infection may not respond to the same treatment. Always finish the full prescribed course unless your vet explicitly tells you to stop.
- 4 My dog vomited the tablet. What do I do? If vomiting happens within 30 minutes of dosing and the tablet is clearly in the vomit, contact your vet — you may need to re-dose. If you’re not sure whether the tablet was absorbed, don’t re-dose without asking, as doubling up can cause additional GI upset. Going forward, give Clavamox with a small meal or a few bites of food rather than on an empty stomach — this is actually the recommended administration method and significantly reduces nausea. The chewable form is often better tolerated than the plain tablet in dogs prone to vomiting.
- 5 Can I use human amoxicillin-clavulanate (Augmentin) for my dog? Tablet forms of Augmentin (amoxicillin-clavulanate) can legally be dispensed to dogs when a vet writes a prescription for it — and many vets do this specifically to save owners money. The chemistry is the same drug. However, do not use human Augmentin without a vet prescription and explicit dosing instructions, because human tablet strengths and ratios differ from the veterinary formulation. The liquid Augmentin sold in human pharmacies uses different ratios and should not be substituted for Clavamox drops without veterinary guidance. Never use chewable Augmentin for humans without first checking that it does not contain xylitol, which is toxic to dogs.
- 6 How long does it take for Clavamox to start working? Clavamox begins absorbing within 1 to 2 hours of a dose, but visible improvement in your dog’s infection typically takes 2 to 5 days. If there is no noticeable improvement after 5 full days of treatment, contact your vet — the FDA package insert specifically notes this as the point at which the diagnosis and treatment should be reconsidered. Lack of response may mean the infecting bacteria are resistant to amoxicillin-clavulanate, in which case a culture and sensitivity test should guide the next step.
- 7 Is Clavamox safe for puppies, pregnant dogs, or dogs with kidney disease? Clavamox is generally considered safe for puppies and has been used in neonatal animals, but dosing and frequency may need adjustment based on age and kidney development. For pregnant or nursing dogs, most vets consider amoxicillin-clavulanate relatively low-risk (FDA Pregnancy Category B in humans), but the decision is made on a case-by-case basis weighing infection severity against any theoretical risk. Dogs with significant kidney or liver disease require veterinary reassessment of dosing intervals, since both drugs are cleared renally and hepatically — standard dosing can lead to accumulation in severely impaired patients.
- 8 What medications should not be given alongside Clavamox? Two antibiotic classes specifically interfere with how amoxicillin works: tetracyclines and chloramphenicol. These bacteriostatic antibiotics (they slow bacterial growth rather than killing outright) can antagonize the bactericidal effect of amoxicillin, reducing its effectiveness. Tell your vet about every supplement, medication, and over-the-counter product your dog is receiving before starting Clavamox. Probenecid — used in some gout medications — can also affect amoxicillin levels. Aminoglycosides (like gentamicin) are synergistic with amoxicillin-clavulanate in some settings, but should never be mixed in the same syringe.
Understanding the mechanism helps explain why this combination exists, why the ratio matters, and what happens when bacteria become resistant to it.
Amoxicillin belongs to the penicillin class of antibiotics — the beta-lactam family. It works by binding to proteins on the bacterial cell wall that are responsible for building and maintaining the wall’s structural integrity. When those proteins are blocked, the wall weakens and eventually ruptures, killing the bacteria. This mechanism works beautifully against a broad range of bacterial species — but only if the amoxicillin reaches the target intact.
Many bacteria have evolved a defense: they produce an enzyme called beta-lactamase that chemically cleaves the beta-lactam ring of amoxicillin before it reaches the cell wall. Once the ring is broken, the drug is inactivated. This is one of the most common mechanisms of antibiotic resistance in veterinary practice. A bacterial infection that fails to respond to amoxicillin alone is frequently producing beta-lactamase.
Clavulanic acid does not kill bacteria. It has almost no direct antibacterial activity by itself. What it does is bind irreversibly to beta-lactamase enzymes, deactivating them before they can destroy the amoxicillin. By sacrificing itself to the enzyme, it keeps the amoxicillin intact and available to attack the cell wall. The combination dramatically expands the spectrum of bacteria that the drug can effectively treat — including Staphylococcus, E. coli, Klebsiella, Pasteurella, Streptococcus, and many anaerobic species that routinely appear in dog skin infections, dental disease, and bite wounds.
The fixed 4:1 ratio of amoxicillin to clavulanate in every tablet strength is not arbitrary — it reflects the pharmacokinetic balance needed to keep enough clavulanate present throughout the dosing interval to protect the amoxicillin as it distributes into tissues.
Even with clavulanate protection, some bacteria can still develop resistance to this combination — through different resistance mechanisms that don’t involve beta-lactamase. Methicillin-resistant Staphylococcus pseudintermedius (MRSP), for example, has become an increasingly recognized problem in dogs with recurrent skin infections. MRSP is resistant to all penicillin-class antibiotics including Clavamox, regardless of the clavulanate. If your dog’s skin infection keeps coming back despite repeated Clavamox courses, ask your vet about a culture and sensitivity test — it identifies exactly which bacteria are present and which antibiotics will actually kill them, rather than continuing to treat empirically.
The FDA package insert explicitly states that prescribing amoxicillin-clavulanate without a confirmed or strongly suspected bacterial infection provides no clinical benefit and increases resistance risk across the wider bacterial ecosystem your dog carries.
There is a meaningful difference between what Clavamox is FDA-approved to treat, what it is commonly used for off-label, and what it simply will not work for. Knowing the difference protects your dog and your wallet.
The primary FDA-approved indication for Clavamox in dogs is bacterial skin and soft tissue infections. This covers the full spectrum of pyoderma — from superficial bacterial skin infections (hot spots, folliculitis, impetigo) to deep pyoderma (furunculosis and cellulitis, where infection reaches below the skin surface). Standard treatment for superficial pyoderma is 5 to 7 days. Deep pyoderma requires a minimum of 21 days, with some cases extending to 30 days. Abscesses, wound infections, and bite injuries also fall in this category — bite wounds in particular carry a heavy anaerobic bacterial burden that amoxicillin-clavulanate covers well.
Clavamox is the only FDA-approved veterinary oral antibiotic specifically indicated for canine periodontal disease, and it is often the drug of choice following dental procedures where infection is present. Periodontal infections in dogs tend to involve a complex mix of aerobic and anaerobic bacteria — exactly the population that amoxicillin-clavulanate’s spectrum covers most effectively. Treatment typically runs 5 to 7 days following a professional dental cleaning. It is not a substitute for the cleaning itself — antibiotics can reduce bacterial load, but they cannot remove calculus or reverse physical periodontal disease without the underlying dental work.
Clavamox is not FDA-approved for UTIs in dogs (it is approved for UTIs in cats), but veterinarians routinely prescribe it off-label for canine urinary infections, and this use is well-supported by clinical literature. Amoxicillin concentrates in the kidney and urine at levels that are effective against many common uropathogens. The standard off-label treatment duration for an uncomplicated canine UTI is 10 to 14 days; complicated UTIs or those involving the upper urinary tract may require longer courses. A urine culture before starting treatment is strongly recommended — not all canine UTIs respond to amoxicillin-clavulanate, and resistance in urinary E. coli and Klebsiella is increasing in practice.
Amoxicillin-clavulanate is sometimes prescribed for bacterial pneumonia and other lower respiratory infections in dogs. The drug reaches lung tissue at reasonable concentrations, and some of the common bacterial causes of canine pneumonia — including Bordetella, Pasteurella, and certain Streptococcus species — are typically susceptible. However, a meaningful proportion of dogs presenting with coughing or respiratory signs have viral, fungal, or other non-bacterial causes that Clavamox will not touch. If your dog is on Clavamox for a respiratory infection and is not improving, the underlying cause may not be bacterial.
Clavamox will not help with viral infections (kennel cough caused by canine parainfluenza or distemper, parvovirus, influenza), fungal infections (ringworm, aspergillosis, valley fever), parasitic skin conditions (mange, yeast overgrowth from Malassezia), or allergic reactions including environmental allergies and food sensitivities. A dog itching, losing fur, or showing red skin does not automatically have a bacterial infection — bacterial pyoderma in allergic dogs is often secondary to an underlying allergy, and the antibiotic clears the bacterial component while the allergy remains. This is why skin infections recur in some dogs after every course: the antibiotic worked, but the reason the skin got infected in the first place was never addressed.
Dosing Clavamox correctly is not complicated — but there are specific details that frequently cause problems when owners don’t have the full picture.
The FDA-approved dose for dogs is 6.25 mg of Clavamox per pound of body weight, given twice daily (every 12 hours). Doses are calculated based on the amoxicillin content of the tablet — not the combined weight of both drugs. The four tablet strengths (62.5 mg, 125 mg, 250 mg, and 375 mg) are all chewable and can be split into halves or quarters for accurate weight-based dosing. For the liquid drops: 1 mL per 10 pounds, twice daily. The drops contain 62.5 mg of Clavamox per mL (50 mg amoxicillin + 12.5 mg clavulanate).
Always give with food. This is not a vague suggestion — food meaningfully reduces the GI upset that is the most common reason dogs are taken off this medication early. A small snack before the dose is enough.
- Superficial skin infections (pyoderma, hot spots, minor wounds): 5 to 7 days minimum — do not stop early even if the skin clears by day 3 or 4
- Deep pyoderma, furunculosis, cellulitis: 21 days minimum — some cases need the full 30-day maximum
- Periodontal disease post-dental cleaning: typically 5 to 7 days
- Urinary tract infections (off-label): 10 to 14 days for uncomplicated cases; longer for upper tract involvement
- No response after 5 full days: contact your vet for reassessment — the FDA package insert flags 5 days as the threshold for reconsideration
- Maximum course length: 30 days total — do not exceed without explicit veterinary direction
Tablets: Store at room temperature, 59–86°F (15–30°C). Keep in the original packaging away from moisture. Do not store in a hot car or a humid bathroom. Tablets do not expire quickly when properly stored.
Liquid drops: Must be refrigerated after mixing with water. Discard any remaining liquid after 10 days — the suspension degrades after mixing and is no longer reliably potent beyond this window. Shake well before each dose. Do not freeze. A common mistake is treating the liquid like a shelf-stable medication — it is not. A course left at room temperature for days may be significantly less effective than when first dispensed.
Give the missed dose as soon as you remember. Then continue the every-12-hour schedule from that point. If it’s almost time for the next dose, skip the missed one and resume the regular schedule — never double up two doses to compensate. Missing one dose rarely compromises the treatment, but missing multiple doses or being consistently late creates gaps in blood and tissue drug concentrations that can reduce effectiveness.
Most dogs tolerate Clavamox without problems. But there are specific reactions that warrant immediate veterinary attention, and knowing the difference matters.
Gastrointestinal upset is by far the most frequently reported reaction — vomiting, diarrhea, loose stools, and decreased appetite collectively occur in approximately 10% of treated dogs. These effects result from the antibiotic altering the balance of normal gut bacteria, a known consequence of all oral penicillin-type drugs. They are generally mild, temporary, and resolve when the course ends. Giving the dose with food is the single most effective strategy for reducing GI side effects. Some vets recommend a probiotic supplement (such as FortiFlora or Proviable) given 2 hours apart from the antibiotic to help maintain gut flora during treatment.
Clavamox contains amoxicillin, a penicillin-class drug with known potential for allergic reactions. The risk of true anaphylaxis is low but real. Signs of an allergic reaction in dogs can develop within minutes to hours of a dose and include: hives or raised welts under the fur, facial swelling (especially around the muzzle and eyes), labored or rapid breathing, sudden collapse or profound weakness, elevated heart rate, drooling, pale or white gums, and seizures. Any of these signs requires immediate emergency veterinary care — do not wait to see if they pass. Dogs with a known allergy to any penicillin-class antibiotic, or to cephalosporins, should not receive Clavamox.
Prolonged antibiotic use disrupts the normal microbial balance across the entire body, not just the gut. In dogs, one of the more practically significant consequences is secondary yeast overgrowth — particularly Malassezia (yeast) in the ears, skin folds, paws, and around the vulva. A dog whose skin infection is clearing on Clavamox but who is developing new head shaking, ear odor, or paw licking may have developed a secondary yeast infection in the ear canals or between the toes. This is not a reason to stop the antibiotic without veterinary guidance, but it is worth flagging at your follow-up appointment. Longer courses (21+ days for deep pyoderma) carry the highest risk.
Accidental overdose in dogs typically produces intensified GI effects: severe vomiting, profuse diarrhea, and significant appetite loss. In rare cases at very high doses, kidney irritation can occur. If you believe your dog received a significant overdose — for instance, a large dog was accidentally given doses calculated for a much larger animal, or the dog ate multiple tablets from a dropped package — call ASPCA Animal Poison Control (888-426-4435) or Pet Poison Helpline (855-764-7661) immediately. Both are available 24 hours a day. Have the tablet strength and approximate number ingested ready when you call.
All four tablet strengths maintain the same 4:1 amoxicillin-to-clavulanate ratio. The difference is purely in tablet size — allowing precise weight-based dosing across small and large breeds.
| Tablet Strength | Amoxicillin | Clavulanate | Approx. Dog Weight | Tablets per Dose | Best For |
|---|---|---|---|---|---|
| 62.5 mg | 50 mg | 12.5 mg | Up to ~10 lbs | 1 tablet | Toy breeds, puppies |
| 125 mg | 100 mg | 25 mg | ~10–20 lbs | 1 tablet | Small breeds |
| 250 mg | 200 mg | 50 mg | ~20–40 lbs | 1 tablet | Medium breeds |
| 375 mg | 300 mg | 75 mg | ~40–60 lbs | 1 tablet | Medium-large breeds |
| Drops (liquid) | 50 mg/mL | 12.5 mg/mL | Any small dog | 1 mL per 10 lbs | Tiny/picky dogs, puppies |
Weight ranges above are approximate guides only. Your veterinarian calculates the precise tablet and dose for your dog’s actual weight. Tablets can be halved or quartered for intermediate weights.
The right approach differs significantly depending on what you’re dealing with. Find your situation below.
Recurrent skin infections — especially in dogs who get better on Clavamox only to develop another infection weeks later — are one of the most common and frustrating presentations in veterinary practice. The most important thing to understand is that Clavamox treats the bacterial infection, not the reason the skin became infected. In the majority of recurrent cases, the underlying driver is an allergy: environmental allergens (grass, dust mites, mold), food allergies, or both. The allergy compromises the skin barrier, allowing opportunistic bacteria to take hold repeatedly. Ask your vet about allergy evaluation and skin cytology before each treatment course — cytology identifies whether bacteria are actually present, and which type, before committing to another antibiotic round.
This is one of the most appropriate and well-supported uses of amoxicillin-clavulanate in dogs. Periodontal disease is a polymicrobial infection involving both aerobic and anaerobic bacteria — precisely the combination this drug handles well. The course is typically 5 to 7 days. Give every dose with a meal, keep the schedule as close to every 12 hours as your routine allows, and finish the full course. If your dog is also on pain medication from the dental procedure, make sure your vet knows everything else in the medicine cabinet — most post-dental pain management combinations are safe alongside Clavamox, but interactions are worth confirming.
Clavamox is a common empiric choice for suspected UTIs in dogs, particularly in female dogs who present with classic lower urinary tract signs. The drug concentrates well in urine and covers most of the common uropathogens. However, if your dog does not show noticeable improvement in urinary signs within 3 to 4 days, contact your vet — the specific bacteria causing the infection may be resistant. A urine culture (ideally taken before starting the antibiotic, or at the recheck visit) is the only way to confirm the drug is appropriate. Recurrent UTIs deserve a culture every time, not repeated empiric treatment with the same drug.
The chewable formulation is specifically designed to address this — it is flavored and intended to be eaten directly. Many small dogs accept the chewable without any wrapping in food. If your dog is still refusing, try placing the chewable inside a small amount of soft food like a pill pocket, a small piece of chicken, or cream cheese. The liquid drops are an excellent alternative for very small or very picky dogs — they contain the same drug at 1 mL per 10 pounds twice daily. Ask your vet to prescribe the drops if the tablets are consistently being spit out rather than improvising with human Augmentin liquid, which uses different concentrations.
Do not stop the medication without calling your vet first. Mild to moderate diarrhea is a known, expected side effect in some dogs on amoxicillin-clavulanate and does not by itself mean the drug needs to be discontinued. Stopping early creates the resistance risk described above and may result in the original infection returning harder to treat. Call your vet and describe the diarrhea: frequency, consistency, and whether there is any blood. If the diarrhea is severe, bloody, or your dog is showing signs of dehydration (sunken eyes, dry gums, excessive lethargy), this warrants a same-day call — not a wait-and-see approach. For mild loose stools, your vet may recommend giving the dose with more food, adding a probiotic, or feeding a bland diet alongside the antibiotic for the remainder of the course.
Most common veterinary medications are safe to give alongside Clavamox — NSAIDs (carprofen, meloxicam), steroids, flea and tick preventives, heartworm medication, and most supplements are not known to interact problematically. The two antibiotic classes that specifically antagonize amoxicillin are tetracyclines (doxycycline, minocycline) and chloramphenicol — if your dog is on either of these for a different infection simultaneously, tell your vet. Also flag any use of allopurinol or probenecid, which can affect amoxicillin elimination. When in doubt, provide your vet with a complete list of everything your dog receives — prescription, over-the-counter, and supplement — before any new medication is added.
There is often a significant price difference between what you pay at the vet’s office and what you can pay at a human pharmacy with a written prescription. Here is what that actually looks like.
Based on real prescription invoice data, a typical 10 to 14-day course of Clavamox (tablets) at a veterinary office ranges from approximately $43 to $75. This includes the dispensing fee. The veterinary exam required to diagnose the underlying infection adds $50 to $100 on top of that, though the exam is necessary regardless of what antibiotic is prescribed. Pet pharmacies and online retailers like Chewy generally price Clavamox drops in the $15 to $35 range for a standard bottle.
If your dog can swallow tablets, ask your vet for a written prescription and fill it as generic Augmentin (amoxicillin-clavulanate) at a human pharmacy. The chemistry is identical — same drug, same manufacturer supply chain in many cases. With a GoodRx coupon, the same 10 to 14-day course at Walmart, Costco, or most major pharmacies costs approximately $10 to $30, compared to $43 to $75 at the vet office. Costco Pharmacy consistently has some of the lowest Augmentin prices, and no Costco membership is required to use the pharmacy in most states. This is entirely legal when done with a valid veterinary prescription — the vet writes it, you fill it wherever you choose.
Important caveats: Do not use human Augmentin liquid as a substitute for Clavamox drops — the human liquid uses different ratios. Never use human chewable Augmentin without confirming it does not contain xylitol, a sweetener that is toxic to dogs. The tablet form is the safe substitution.
Yes — when Clavamox is prescribed for a covered condition (skin infection, UTI, dental infection, wound), it is included in the insurance claim for the underlying condition at the policy’s reimbursement rate, typically 70 to 90% after the deductible. Because Clavamox itself is relatively inexpensive, the insurance benefit on the medication alone is modest. The real savings from pet insurance tend to come from the exam, diagnostics (urinalysis, culture, skin cytology), and any follow-up visits — not the prescription cost itself. If you are deciding between filling at the vet versus a human pharmacy for insurance purposes, check whether your policy requires purchase from a licensed veterinary pharmacy — some do, most don’t.
Do not use leftover Clavamox from a previous prescription for a new infection without veterinary guidance. The previous infection and the current one may not be caused by the same bacteria, and giving an antibiotic without diagnosing the current infection can delay proper treatment while contributing to resistance. Do not purchase Clavamox from unregulated online sellers — counterfeit or improperly stored veterinary medications have been documented and may be ineffective or harmful. And do not attempt to use human Augmentin liquid or chewable tablets without specific veterinary guidance on the equivalent dose and formulation compatibility.
This content is for general informational and educational purposes only and does not constitute veterinary medical advice, diagnosis, or treatment. All drug information reflects the FDA-approved package insert for Clavamox® (amoxicillin and clavulanate potassium), manufactured by Zoetis, NADA 055-099 and 055-101, along with established veterinary pharmacology references. Always follow your veterinarian’s specific dosing instructions for your dog’s individual health status, weight, and condition. Never begin, stop, or alter a prescription medication without veterinary guidance. If you believe your dog is having an adverse reaction, contact your veterinarian or an emergency animal hospital immediately. ASPCA Animal Poison Control: 888-426-4435 · Pet Poison Helpline: 855-764-7661 (consultation fees may apply). Drug pricing information reflects general market data and may vary by location and pharmacy. Clavamox® is a registered trademark of Zoetis Inc. This content is not affiliated with, sponsored by, or endorsed by Zoetis or any pharmaceutical company.