The FDA has approved a new version of Convenia for dogs, and it comes with a warning that matters if you also live with a cat.
The original Convenia (cefovecin) was approved in 2008 for skin infections in both dogs and cats. The new one, Convenia RTU for Dogs, is approved for dogs only. Same active ingredient, but two of the inactive ingredients, benzyl benzoate and propylene glycol, may be toxic to cats. It is also twice as concentrated, 160 mg/mL instead of 80 mg/mL, and comes as a 10 mL multiuse vial.
It treats skin infections caused by Staphylococcus pseudintermedius and Streptococcus canis. Both bacteria normally sit on healthy dog skin without doing harm. They become a problem when scratching, allergies or an injury breaks the skin barrier and lets them multiply.
What this means for your dog: the injection is not new, the formulation is. For a dog that fights pills, a single shot is a genuinely useful option, and a more concentrated version means less liquid for the same dose. Vets are told to shake the vial for 60 seconds and use a 20 gauge needle. Zoetis makes it, and it is prescription only.
The cat part is the part to remember. If you have both species at home, do not assume a dog’s medication is fine for the cat because the drug name sounds familiar. Ask which formulation your vet is drawing up, and keep the used vial and syringe where nobody can reach them. Skin infections usually start with an itch, so it helps to understand why allergies and scratching travel together. If the scratching started with the season, fall allergies are the usual suspect.