Convenia Long-Acting Antibiotic Injection

“Awwww, Doc, can’t you just give him a shot?”

Usually that question comes from a pet lover in the form of an objection to having to give oral medications for a two week or longer time period. Up until now our answer has been, “No, an antibiotic injection will last 12 to 24 hours, then we would have to give another one. Do you want to come in every day for 14 days for injections at $35.00 each?”

But the times, they are a’changing.

Enter Convenia, (cefovecin sodium) the long-acting antibiotic from Pfizer Animal Health that lasts 10 to 14 days with a single injection. Convenia is more than just penicillin. It’s a broad-spectrum antibiotic (in the simplest terms that means it kills a lot of different kinds of bacteria), so it can be used in a wide variety of infected organ systems and clinical and hospital situations.

Convenia isn’t right for every infection. If it were, it would be the only antibiotic on the market. Instead, there are hundreds and hundreds of antibiotics, each with a situation or organism on which it works best.

If my pet were a patient, I would sure ask my pet’s doctor if Convenia (cefovecin sodium) were right for him.

covenia, convina, convinia, covinia


  1. I took my cat to the vet, and he diagnosed her as having an infected salivary gland. He recommended using Covenia as he wants her to have a total of 4 injections over the course of 2 months. I have used Covenia in the past with great success. Unfortunately, he didn’t have any available that day, but said he would overnight the medicine via the post office later that week given that it is a 10-hr round trip drive for me to get there, and I have to pay $160 for gas and to take my car on a ferry (I live on an isolated peninsula).

    The medicine actually took 2 days to arrive and was shipped in a small, non-insulated metal thermos. There was melted water in the thermos, presumably from a couple of ice cubes. However, by the time I received it, the water was room temperature.

    The Covenia instructions state it needs to be stored both in its powder and reconstituted forms at 36-46 degrees Fahrenheit. The water & inside of the thermos were definitely not that cold – 65-70 degrees F at best.

    My vet says it should still be okay since it was unrefrigerated for only a short time. He will not refund my money or send a new bottle. I am skeptical but do not want to pay another $200 for a new bottle (not to mention the same problem of how to get it to my house). I am frustrated because I have no way of knowing if it is still good or not except to simply use it and hope that it works and helps my sick cat.

    What do you think??

    • I think I would have already been on the phone to suspected adverse event“>Zoetis and asked them their opinion. You will find the staff there professional and happy to help. Please keep in mind that the financial transaction was between you and the doctor, I wouldn’t expect Zoetis to feel obligated to replace the vial for you, but they should be able to at least render an opinion on whether the cefovecin is still active. I’d be interested in knowing how this is resolved for you, if you don’t mind posting the outcome for us. Thank you.

  2. My cat was given Convenia after having some skin allergic issues below his ears. He now has a bad respiratory infection, sneezing hacking. Is this normal?

  3. hi, my 4yrs 9moth lurcher/staffie cross was given convenia approx 2 months ago. she seems a little down in herself and over the past 3 days i have noticed a small amount of urine dripping from her. Do you think this could be a side effect of convenia? and is there anything I can do for her, she’s seeing the vet that gave her the injection today but I’m not sure they would be forthcoming about it being down to the convenia as the they told me at the time there were no side effects to this injection (when i specifically asked would there be any side effects). I’m terribly worried about her.
    thank you .

    • Two months ago? That’s a bit of a reach, don’t you think? The bottom line is, if you see your pet’s doctor today and you still think her health problems are Convenia-related, you can contact Zoetis and file a report with them about a suspected adverse event. We will be very interested to know the outcome of her case, and would greatly appreciate a followup report. Thank you for reading.

      • Hi there, she was seen by her vet yesterday, he says her symptoms are not related to the injection ( I wasn’t blaming the injection, i was just concerned it may have been a factor), she has been on steroids and he thinks between the steroids and her being neutered (the incontinence being down to this) that he is not concerned about her. its put my mind at rest, I know I sound like an overbearing mother but she means the world to me.
        shes off the steroids now and hopefully in the next few days she’ll be back to normal.
        thank you very much for replying.
        best wishes.

  4. Hi Dr. Randolph, so I have Bengal cat. He’s about 9 to 10 years old, we don’t know for sure cause he showed up at home and never left. He had some dental issues a month ago, so he got two neck lesions extraction last April 4th. I was happy thinking that he’d be back to himself. About 12 days later after procedure I noticed he was having foul odor coming out his mouth, and he was putting his paw on his mouth over and over. Plus he was having trouble bathing, like something in his mouth was bothering him. I took him to vet, she said he got an infection. She gave him two shots Convenia and Penicillin. This was 2days ago. He’s not having any problem eating his can food. But I can tell he is in a lot pain, he’s very demotivated, put his paw on his mouth a lot. Not playful, don’t want lap (that’s his favorite thing). I’m so frustrated. I don’t know how long it takes to kick in. I’m so afraid to lose my baby Kitty

    • If I were in your situation, I would seek the advice of a board-certified veterinary dentist. You may have to drive to a nearby larger city, but it will be time well-spent. If there is going to be a delay before you can see the dentist, ask your local veterinarian to run these laboratory tests in the meantime. Please write back and let me know what is found. Thank you for reading, Dr. Randolph.

  5. My beloved rescue Norweigan Forest Cat Wedgie had a lick granuloma that made his right back paw look like a “Fred Flinstone Foot”. He received Convenia last Friday and yesterday gradually lost coordination in his back legs. He is awake and alert and eats when I hand feed. He is literally hanging out in his litter box (not great for the granuloma) so I put him in his bed nearby. He almost looks like a person with Guillian Barre. Yes I am taking him in to the vet but I want to be mentally ready for the diagnosis—med side effect? will it resolve or is this a terminal event?


  6. My 11 year old Yorkie was given Convenia yesterday for pancreatitis. This was not his first episode, but was the first time receiving this injection. But the vet also said that he needed Flagyl to cover what Convenia didn’t. He’s had Flagyl in the past, but was given 250 mg twice a day (a previous vet’s dosing.) However, with this current vet, he was prescribed 1/4 of 250 mg twice a day. That just doesn’t seem sufficient, especially when I read the minimum dosing is 11 mg per kg of body weight, which he is 13 pounds. Was he prescribed less because he had the Convenia? On a side note, my dog NEVER eats table scraps and has been on a low fat diet for the past three years of Hills W/D and Royal Canin Gastrointestinal Low Fat. It’s interesting that he has no diarrhea, but I saw that he had vomited (I assume) frank bright blood. There was nothing in it so it’s hard to tell which end it came from. His pancreatitis test was positive. I just want to make sure he’s getting all the right medication at the right dose.

    • In my experience, metronidazole is one of those drugs I’ve seen doctors use a WIDE range of doses with success. I wouldn’t think that dose would result in problems, but, if he’s not doing well enough Tuesday when the doctor reopens, you can ask him/her to reconsider the dose. Pancreatitis is a tricky condition. Sometimes you do everything right and it still does whatever it wants to. Still, keep doing all of the preventive measures and you maximize your chances of avoiding at least some episodes. Thanks for reading

  7. Well, thankfully the 2 week (14 days) mark of Convenia is today. She seemed to tolerate it ok, but I read that the drug still stays in their system for up to 2 months. ” It exerts its antibacterial effects for approximately 1-2 weeks but stays in the body for over 2 months.” I am not sure what that means…what exactly stays in their system? and what is the potential harm? Does anyone know? Thank you.  

  8. My cat was given a shot of Convenia today for suspected UTI. I did ask vet about side effects and she said they tolerate it well. Well, my cat has been walking funny and basically limping since she came home. She is eating and seems ok. Obviously, she was not limping before so it could only be the Convenia. Is this a possible side effect with Convenia and will it go away. My cat is 19 and only 5 lbs. she does not need further complications. Thank you.

  9. My 15 yo cat started sneezing last Sunday. (My other cat had just been treated for a URI, so I was not surprised.) I took him to the vet Monday to try to catch it early. He was given a convenina injection and meds in his ears for additional ear infection.

    It is now Saturday – 5 days since the injection – and my cat is ten times worse. His eyes are running, his nose is congested and running, and every so often he “snorts” like he’s having difficulty breathing. I called my vet on Wednesday to tell them he was getting worse and was told “it will get worse before it gets better”.

    How long before I should see improvement from the injection? This seems highly abnormal.

    • Actually, it’s exactly what one might expect. It’s the reason your pet’s doctor said, “it will get worse before it gets better.” Most of these patients are infected with a combination of viruses, bacteria and, sometimes, Chlamydia. Click here to read more. That said, some of these patients also need supportive therapy, such as IV fluids, nose cleaning, nebulization, sometimes other modes of therapy. Such treatment is usually provided by emergency clinics, but your veterinarian may provide 24-hour care. Check with him/her. Thanks for reading

  10. Our 5 year old cat was diagnosed with IMHA a little over 2 years ago. We have “managed” this illness with Prednisolone and CellCept — PCV goes up (high as 34) and down (low as 15) and we have been unable to reduce dosage without PCV dropping. She occasionally has had bouts of severe sneezing with nasal discharge and our vet has given Covenia which always clears up the issue in a few days. At our last visit, we were told that her kidneys were enlarged and she was given a Covenia injection. Considering her health history, should a different antibiotic be used? It has been 5 days since the injection and her kidneys are still palpable/enlarged. Thank you in advance for your reply.

    • Hmmmmmm … I’ve wracked my brain, and I can’t come up with a single scenario in which enlargement of the kidneys would be related to Convenia. The next step, diagnostically, if you wanted to pursue it, would be ultrasound of the kidneys. However, unless the enlargement is significant, or urine output is reduced, or she is feeling poorly, I’m not convinced it’s something to pursue. Thanks for reading

      • Dr. Randolph, Thank you so much for your reply. We realize we are fighting a losing battle with primary IMHA and would surmise the kidney enlargement is a result of the disease and the long term steroid use (substantial dosage — 10mg twice per day and our girl weighs 10 lbs) . Unfortunately, we are unable to reduce the dosage; each time we have attempted to reduce (sometimes by as little as 1/4 pill) her PCV starts to drop. The Convenia injection was simply a “what if she has infection?” possible solution to the kidney enlargement. She has a good appetite, urine output is not reduced, she is drinking slightly more water than usual but not by a substantial amount, and doesn’t appear to be in any pain. I think she is somewhat uncomfortable because she no longer sleeps on her back. We have fought a good fight and will continue to do all we can do until we cannot do any more and her quality of life is diminished/she is in pain that cannot be alleviated. We love her dearly. Thank you again for your reply.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.