Clavamox is a prescription antibiotic for dogs that combines amoxicillin with clavulanic acid, a compound that prevents bacteria from breaking down the antibiotic. It’s one of the most commonly prescribed veterinary antibiotics, FDA-approved specifically to treat skin infections, soft tissue infections, and periodontal disease in dogs.
How Clavamox Works
Many bacteria produce an enzyme that destroys amoxicillin before it can kill them. This is one of the main ways bacteria become resistant to antibiotics. Clavamox solves this problem by pairing amoxicillin with clavulanic acid, which blocks that enzyme. With the enzyme neutralized, amoxicillin can do its job and kill bacteria that would otherwise shrug it off.
This two-ingredient approach makes Clavamox effective against a wider range of bacteria than amoxicillin alone, including several resistant strains of Staphylococcus and E. coli. However, it does not work against methicillin-resistant Staphylococci (MRSA and MRSP), which require a different antibiotic entirely.
What Clavamox Treats
Clavamox is FDA-approved for two categories of infections in dogs:
- Skin and soft tissue infections: wounds, abscesses, cellulitis, and pyoderma (bacterial skin infections, including both superficial and deep forms)
- Periodontal infections: bacterial infections of the gums and tissues around the teeth, caused by both aerobic and anaerobic bacteria
Veterinarians also prescribe Clavamox off-label for urinary tract infections and upper respiratory infections, though these uses aren’t part of the official FDA labeling. Your vet may choose Clavamox for these conditions based on the specific bacteria involved.
Dosage and Forms
The standard dose for dogs is 6.25 mg per pound of body weight, given twice daily. So a 40-pound dog would typically receive 250 mg per dose. Your vet will calculate the exact dose based on your dog’s weight and the type of infection being treated.
Clavamox comes in two forms: chewable tablets and a liquid suspension (called Clavamox Drops). The liquid form is especially useful for small dogs or puppies that can’t easily take tablets. You can give Clavamox with or without food, though giving it with a meal can help reduce stomach upset.
How to Store It
Tablets can be stored at room temperature. The liquid suspension is a different story: once the powder is mixed with water, it must be refrigerated and discarded after 10 days. Shake the bottle before every use to ensure the medication is evenly distributed. Using expired liquid suspension means your dog may not get the correct dose, since the active ingredients degrade after that 10-day window.
Common Side Effects
The most frequent side effects are gastrointestinal: diarrhea, vomiting, and loss of appetite. These are generally mild and often resolve on their own as your dog adjusts to the medication. Giving Clavamox with food can help minimize nausea.
More serious reactions are uncommon but worth knowing about. Contact your vet immediately if you notice fever, skin rashes, difficulty breathing, or pale gums. These can signal an allergic reaction, which requires prompt treatment. Dogs with a known allergy to penicillin-type antibiotics should never take Clavamox, since amoxicillin belongs to the same drug family.
Drug Interactions and Safety Concerns
A few medications interact with Clavamox. The chemotherapy drug methotrexate can build to toxic levels when used alongside amoxicillin, so your vet needs to know if your dog is receiving cancer treatment. Several other antibiotics, including tetracycline, erythromycin, and chloramphenicol, can interfere with how Clavamox works and should be used cautiously in combination.
One critical safety note: Clavamox should never be given to rabbits, hamsters, guinea pigs, or other rodents. In these species, it disrupts gut bacteria severely enough to cause life-threatening diarrhea. If you have multiple pets and one is prescribed Clavamox, keep the medication away from small animals in the household.
Getting the Most Out of Treatment
Finish the entire course of antibiotics, even if your dog looks and feels better before the medication runs out. Stopping early is one of the main drivers of antibiotic resistance, and it increases the chance the infection will come back. If your dog vomits within 30 minutes of a dose, contact your vet about whether to re-dose.
If your dog develops persistent diarrhea or refuses food for more than a day while on Clavamox, let your vet know. They may adjust the dose, recommend a probiotic, or switch to a different antibiotic depending on how your dog is responding.