Convenia for Dogs: How Long It Lasts, Side Effects & the 65-Day Catch
Last reviewed: September 2026
One injection, and no way to take it back
Convenia (cefovecin) replaces a fortnight of tablets with a single injection at the clinic. That solves the pilling problem completely — and creates a different one, because the drug cannot be withdrawn once given.
What Convenia Is
Convenia is the brand name for cefovecin, a long-acting cephalosporin antibiotic given as a single injection under the skin at 8 mg/kg (3.6 mg/lb). In dogs it is approved for skin infections — secondary superficial pyoderma, abscesses and wounds — caused by susceptible Staphylococcus intermedius and Streptococcus canis. There is no tablet and nothing for you to give at home. A maximum of two injections should be given.
How Long Does Convenia Last in Dogs?
Two different answers, and conflating them is the usual source of confusion.
- • How long it treats: therapeutic concentrations last about 14 days against Streptococcus canis, and about 7 days against Staphylococcus intermedius and Pasteurella multocida. So "it lasts 14 days" is only true for some infections.
- • How long it stays: the drug can persist in the body for up to 65 days — long after it has stopped doing useful work.
If your dog is not improving a week after the injection, do not assume there is more to come. For a staph infection the working window may already be closing, and that is a reason to go back rather than to wait out the fortnight.
The Trade-off Worth Understanding
The case for Convenia is strong and often underrated: a course that actually gets given beats a better course that does not. For a dog that cannot reliably be pilled twice daily for two weeks — and many cannot — a single injection removes compliance from the equation entirely. Half-finished antibiotic courses are a real driver of resistant infections.
The cost is that it is irreversible. With Clavamox or another tablet, a reaction means not giving the next dose. With Convenia the drug is already in and may persist for weeks. That matters most for a dog with a history of drug reactions, or one with kidney or liver disease where clearance is slower. It is a fair question to ask before agreeing to the injection, not a reason to refuse it.
Keep a record of what your dog has been givenSide Effects
The commonly reported effects are digestive — reduced appetite, vomiting, diarrhoea — along with lethargy. Because the drug is long-acting, these can persist rather than stopping the day you would have skipped a tablet. Allergic reactions are uncommon but, as with any cephalosporin, possible; facial swelling, hives or difficulty breathing need same-day attention. Tell your vet if your dog has ever reacted to a penicillin or cephalosporin.
Frequently Asked Questions
How long does Convenia last in dogs?
It depends on the bacteria being treated. After one injection, therapeutic concentrations are maintained for about 14 days against Streptococcus canis and about 7 days against Staphylococcus intermedius and Pasteurella multocida. Separately from how long it is working, the drug itself can persist in the body for up to 65 days.
What is the Convenia dose for dogs?
8 mg/kg (3.6 mg/lb) as a single subcutaneous injection given by your veterinarian. There is nothing for an owner to measure or give at home. A maximum of two injections should be given.
Can Convenia be stopped if my dog reacts to it?
No, and this is the main trade-off. Once injected it cannot be withdrawn, and it can persist in the body for up to 65 days. With a tablet, a reaction means stopping the next dose; with Convenia the drug is already in. That is worth weighing against the convenience, particularly for a dog that has reacted to antibiotics before.
What is Convenia used for in dogs?
It is approved for skin infections in dogs - secondary superficial pyoderma, abscesses and wounds - caused by susceptible strains of Staphylococcus intermedius and Streptococcus canis.
Why would a vet choose an injection over tablets?
Because a course that is actually given beats a better course that is not. For a dog that cannot be reliably pilled twice daily for two weeks, a single injection removes the compliance problem entirely. That is a real clinical advantage, not just convenience.
Sources
- DailyMed — Convenia (cefovecin sodium) label
- FDA Freedom of Information Summary — cefovecin sodium
- Merck Veterinary Manual — Cephalosporins Use in Animals