Clavacillin is an antibiotic prescribed to dogs for skin infections, soft tissue infections, and periodontal (dental) disease. It combines two active ingredients: amoxicillin, a penicillin-type antibiotic, and clavulanate potassium, which prevents bacteria from disabling the antibiotic. Your vet may also prescribe it off-label for bite wounds, bladder infections, and upper respiratory infections.
How Clavacillin Works
Many bacteria that infect dogs, especially Staphylococcus species, produce an enzyme that breaks apart penicillin-type antibiotics before they can do their job. Ordinary amoxicillin on its own would be useless against these bacteria. Clavulanate solves that problem by binding irreversibly to the enzyme and destroying it, leaving the bacteria defenseless against amoxicillin. This is why the combination can treat infections that plain amoxicillin cannot.
One important limitation: methicillin-resistant Staphylococci (MRSA and MRSP) are resistant to this combination, so a different antibiotic is needed for those infections. Your vet may run a culture and sensitivity test if the infection isn’t responding to treatment.
FDA-Approved Uses
Clavacillin is FDA-approved (under ANADA # 200-592) for two categories of canine infections:
- Skin and soft tissue infections: wounds, abscesses, cellulitis, and both superficial and deep pyoderma caused by susceptible strains of Staphylococcus aureus, other Staphylococcus species, Streptococcus species, and E. coli.
- Periodontal infections: bacterial infections of the gums and tissues around the teeth, including both aerobic and anaerobic bacteria.
Common Off-Label Uses
Veterinarians frequently prescribe Clavacillin beyond its labeled indications. Typical off-label uses include infected bite wounds, bladder infections, upper respiratory infections, and infected teeth. Because skin infections in dogs are almost always caused by Staphylococci, and because this drug specifically targets those bacteria, it has become one of the most commonly prescribed antibiotics in veterinary practice.
For periodontal disease specifically, research shows amoxicillin-clavulanate is most effective when combined with a professional dental cleaning rather than used alone. The antibiotic provides additional improvement in severe or stubborn cases of gum disease, but it works best alongside mechanical removal of plaque and tartar.
How Long Treatment Typically Lasts
Treatment length depends entirely on the type of infection. For bladder infections, older guidelines recommended 10 to 14 days, which produced clinical cure rates around 70 to 80 percent and bacterial elimination rates of 85 to 90 percent. More recent guidelines from the International Society for Companion Animal Infectious Diseases now recommend just 3 to 5 days for straightforward bladder infections, as shorter courses appear to work just as well.
Skin infections usually require longer treatment. Superficial pyoderma often calls for two to three weeks, while deep skin infections can need four to six weeks or more. Your vet will likely want to continue the antibiotic for a period after symptoms have visibly cleared to ensure the infection is fully resolved. Stopping early is one of the most common reasons infections come back.
Dosing and How to Give It
The standard dose for dogs is 6.25 mg per pound of body weight, given twice daily. Clavacillin comes in tablet form at several strengths to accommodate dogs of different sizes. Giving it with food can help reduce stomach upset, which is the most common complaint.
The tablets should stay in their foil packaging until you’re ready to give one, since moisture and heat can degrade the medication. Store them at room temperature, between 68 and 77°F.
Side Effects to Watch For
Most dogs tolerate Clavacillin well. The most frequently reported side effects are gastrointestinal: vomiting, diarrhea, and loss of appetite. These are usually mild and often improve when the medication is given with a meal.
Allergic reactions are possible but uncommon. In rare cases, dogs can develop skin reactions including new rashes, redness, or worsening of the skin condition they’re being treated for. Itching is a variable sign that may or may not accompany an allergic response. If your dog develops hives, facial swelling, difficulty breathing, or a skin condition that’s getting worse rather than better on the medication, that warrants prompt veterinary attention. True drug allergies to this class of antibiotics, while rare in dogs, do occur and mean the drug should be permanently avoided in that animal.
Dogs That Shouldn’t Take Clavacillin
Dogs with a known allergy to penicillin-type antibiotics should not receive Clavacillin. If your dog has had a reaction to amoxicillin, ampicillin, or any other penicillin in the past, let your vet know before starting treatment. There is also some cross-reactivity with cephalosporin antibiotics, so a history of reactions to those is worth mentioning as well.