Convenia is a long-acting antibiotic injection given to dogs to treat skin infections. Its active ingredient, cefovecin sodium, is a third-generation cephalosporin that kills bacteria by stopping them from building their cell walls. What makes it unusual is that a single shot provides up to 14 days of antibiotic activity, eliminating the need for owners to give pills at home.
What Convenia Treats in Dogs
Convenia is FDA-approved specifically for skin infections in dogs, including superficial pyoderma (bacterial skin infections that cause pustules and crusting), abscesses, and infected wounds. It targets two bacterial species: Staphylococcus intermedius and Streptococcus canis, both common culprits in canine skin infections.
Some veterinarians use Convenia off-label for other bacterial infections, but it is not approved for urinary tract infections or respiratory infections in dogs. Because it’s a broad-spectrum antibiotic, there’s growing attention in veterinary medicine to reserving it for cases where it’s genuinely the best option rather than defaulting to it for convenience.
How the Injection Works
Your vet gives Convenia as a single subcutaneous injection (under the skin) at a dose of 8 mg per kilogram of body weight. The drug binds tightly to proteins in your dog’s bloodstream, which is what allows it to release slowly over days rather than hours. That sustained release keeps antibiotic levels high enough to fight infection for up to 14 days from one shot.
If the infection hasn’t fully resolved after two weeks, a second injection can be given. Two injections, spaced 14 days apart, effectively deliver a full month of antibiotic coverage.
Why Vets Choose It Over Oral Antibiotics
The biggest advantage of Convenia is compliance. Oral antibiotics for skin infections typically need to be given once or twice daily for two to four weeks. Many dog owners struggle with this, whether because the dog spits out pills, hides them in cheek pouches, or becomes increasingly resistant to the routine. Missed doses reduce the antibiotic’s effectiveness and can contribute to bacterial resistance.
With Convenia, the full course is delivered at the vet’s office. There’s no risk of a forgotten dose or an incomplete course. Veterinarians frequently cite this guaranteed compliance as the primary reason they reach for it, particularly for dogs that are difficult to medicate or for owners who have demanding schedules.
Side Effects to Watch For
Most dogs tolerate Convenia well, but side effects do occur. The more common reactions include sluggishness, loss of appetite, vomiting, diarrhea, and mild swelling or irritation at the injection site. These are typically self-limiting and resolve within a day or two.
Rare but serious reactions are also possible: facial swelling, difficulty breathing, blood cell and bone marrow abnormalities, and elevated liver enzymes. In very rare cases, severe reactions have been fatal. The critical thing to understand about Convenia is that once it’s injected, it cannot be removed from your dog’s system. If your dog has a bad reaction to an oral antibiotic, you simply stop giving the pills. With Convenia, the drug continues working in the body for weeks. Adverse effects can appear up to two months after the injection, long after the visit to the vet.
This irreversibility is worth discussing with your veterinarian, especially if your dog has never received a cephalosporin antibiotic before.
Dogs Who Should Not Receive Convenia
Convenia is contraindicated in dogs with a known allergy to cefovecin or to any antibiotic in the beta-lactam family, which includes all penicillins and cephalosporins. Cross-reactivity between these drug classes means a dog that has reacted badly to amoxicillin, for example, could also react to Convenia. If your dog has ever had an allergic response to a penicillin-type antibiotic, make sure your vet knows before the injection is given.
What Convenia Costs
Convenia is priced by body weight, so larger dogs pay more. Based on the manufacturer’s 2025 suggested resale pricing, here’s what to expect for a single injection:
- Small dogs (10 lb): approximately $61
- Medium dogs (30 lb): approximately $102
- Medium-large dogs (50 lb): approximately $144
- Large dogs (75 lb): approximately $196
- Extra-large dogs (100 lb): approximately $247
These are suggested prices from Zoetis, the manufacturer. Your vet sets the final price, which may be higher or lower depending on the clinic. The cost also doesn’t include the office visit fee. If a second injection is needed two weeks later, you’ll pay for another dose. For a 50-pound dog needing two injections, the drug cost alone would be roughly $288, not including exam fees.
By comparison, a course of generic oral antibiotics for skin infections often runs $20 to $60 total. Convenia’s higher cost reflects the convenience factor and the guaranteed compliance it provides.
What to Expect After the Injection
Most owners notice improvement in their dog’s skin infection within the first few days. Redness and discharge from wounds or abscesses typically begin to decrease as antibiotic levels build in the bloodstream. Full resolution of skin infections can take the entire 14-day treatment window, and some dogs need a second injection to completely clear the infection.
During the weeks following the shot, keep an eye on your dog for any of the side effects mentioned above. Because the drug stays active so long, new symptoms appearing a week or even several weeks after the injection could still be related to Convenia. If your dog develops facial swelling, labored breathing, unusual lethargy, or stops eating, contact your vet promptly and mention the Convenia injection, even if it was given weeks earlier.