Conscious Cat

September 26, 2011 491 Comments

Convenia for Cats: Sacrificing Safety for Convenience?

Posted by Ingrid

cat injection vaccination veterinarian

Most cat owners know that medicating a cat can be challenging. That’s probably why many veterinarians as well as cat owners celebrated when Convenia, a long-acting, injectable antibiotic, came on the market in 2008. Convenia is manufactured by Zoetis, formerly Pfizer Animal Health.

The idea of a one-time injection, instead of giving regular anitibiotics in pill or liquid form once or twice a day for two weeks or more, seemed like a great solution to the problem.

However, contrary to regular antibiotics, which are rapidly cleared from the body, Convenia stays in the body for two months or longer following injection, even though the antibacterial effects only last for two weeks. All drugs have some side effects. While some cats may do just fine with Convenia, others may have side effects ranging from mild to life threatening. And with a long acting drug like Convenia, there is no way to simply stop giving the medication – it’s already in your cat’s system.

Amber was one of those hard-to-pill cats. After careful discussion with my vet, I agreed to use Convenia following a dental procedure, which I’ve now come to learn is an inappropriate use for this drug. At the time, I only had misgivings about it because of its long-acting properties. Thankfully, she had no side effects other than some mild diarrhea, which is a common side effect of most antibiotics.

I recently came across a comprehensive article about Convenia by Dr. Lisa Pierson, the founder of, one of the best and most comprehensive websites about feline nutrition. In her article, Dr. Pierson weighs the pros and cons about administering this drug to cats:

Convenia: Worth the Risk?

Dr. Pierson’s article is a must read for all cat owners.

Editors’s note: comments about your  experience with Convenia are welcome. Comments that are disrespectful of others or malign the veterinary profession or individual veterinarians will be deleted.

References to other resources and/or websites or Facebook pages about Convenia which may be provided in the comments section are not endorsed by the site owners.

Photo: istockphoto

Dr. Goodpet


491 comments to “Convenia for Cats: Sacrificing Safety for Convenience?”

  1. EvaServal says:

    Hi Saguil,
    Keeping you and your kitty in my prayers. Please do get your kitty on the probiotics that Catlady is recommending…
    All the best.

  2. we adopted a kitten Lili, from a humane society, she came with the normal humane society issues, upper respiratory, weeping eye. I brought her home on Sept 11, 2014. She had been spayed. Lili was so tiny 1.5lb, I thought she was 6-7 weeks old. We returned home and I was reviewing her paperwork and discovered she was close to 12 weeks old. She was very active fit right in with our other cat and 110lb dog. She acted like a typical “crazy” kitten, she loved being cuddled and would curl up under my neck to nap. I wanted her checked out by our own vet. I brought her in the next day Sept 12th, he agreed she had an upper respiratory infection and that she was very small for her age but healthy. He suggested the convenia shot, I agreed. I did ask about side effects and what to watch for, he did say she could be tired for a day or 2, she was. A month plus, Lili started to sneeze, green “snot” started to appear around her nose so we brought her in again. On November 3rd they gave her a second shot of convenia. She started to go down hill immediately. She would just sleep, no more playing she didn’t even care to cuddle. We brought her in on November 26th and they placed her on a second oral antibiotic after conducting testing for Feline Lukkemia and other feline issues. I told the vet that I think it was the shot, because she went downhill right after that second shot. Lili could hardly walk, when she did she would stagger and fall over. She began to pee and poop where she was sleeping. I purchased a baby animal milk formula thinking it would be like “ensure” I would give her water with a syring to make sure she was getting some water. She would stagger to the water and food bowls but ate very little. We brought her to the vets to board her as my husband was going to Mayo for cancer surgery and we couldn’t leave her home with the person watching our other pets, we realized Lili needed extra attention. This was on Dec 2nd, 6 days after her last visit……they recommended that we put her down, her temp was 10 deg below norm, her kidneys were failing. I was sick. I told the vet that I read up on the shot convenia and believe this is was the start of her failings, I said I am not blaming anyone but feel I should have been told the side effects not just that it is an antibiotic and is used all of the time without problems…..they don’t know that…..people may not make the connection with their sick pet getting sicker after the shot and just think it’s the illness. I know in my heart that shot was what started Lili’s downslide and eventually forced me to make that heartbreaking decision, euthanizing her. In less than 3 months I spent over $500.oo to kill my poor little kitten.

    • Ingrid says:

      Oh Terry, I’m so sorry about Lili. My heart goes out to you.

    • Lesley Le Page says:

      Terry, I absolutely feel for you and your poor little kitty. Convenia successfully killed two of my cats. The first one was ill with breathing difficulties, took her to the vet, Convenia was administered and immediately she began staggering when I tried to put her back in the cat carrier. She improved after about a week, but then suddenly disappeared. We found her later – she had died alone, in the wet and cold. I insisted that our vet put a report into the manufacturers, Pfizer. I left instructions with the vet to put on their system that Convenia should never be used on any of our cats or dogs in the future. When another of our cats became poorly, my daughter took her to the vet. They gave her Convenia! She died the next day in my arms. THIS DRUG SHOULD BE TAKEN OFF THE MARKET AND PFIZER SHOULD BE SUED!

    • Vicki says:

      Terry please file a report with Zoetis (the manufacturer) and FDA – see Dr. Pierson’s article for contact info).

      My Leo died back in July from Convenia. We had a necropsy performed and I spoke with both of these organizations. The FDA said that only about 1% of people actually follow through with a report and they must have significant amount of data before anything can be done. She thanked me for calling. Please ask your vet to send in a report as well.

      I’m so sorry about Lili…it is heartbreaking.

  3. EvaServal says:

    Terry, I’m so very sorry… heart breaking… :(

  4. R A Sullivan says:

    We have a 14 y.o. Tuxedo cat who has epilepsy. She has been successfully treated with phenobarbital for several years, with NO breakthrough seizures. we have routine blood analysis to check kidney and liver function.
    Recently she had a large abscess on her chin. The vet suggested Convenia to my husband because of the convenience of its dosing. Never were we told that it remains in the tissue for more than 60 days. Our cat has had two seizures in one week, one a massive event over 3 minutes long. Neither vet had any information regarding the concurrent use of anti-convulsants with Convenia. I have provided them that information copying it directly from a professional website. Seizure are a serious side effect. I am not a blame placer , but a problem solver. I suggest anyone who has had this happen to them to report it immediately to the Convenia website. We will never allow the use of Convenia with out cats.

    • Ingrid says:

      I’m sorry this happened to you. Please report this to the FDA as well. All my best to your kitty for a complete recovery.

      • EvaServal says:

        R.A. Sullivan, I’m so ver sorry about your sweet cat… my condolences.

      • EvaServal says:

        My sincere condolences. All these incidents are horrible and unnecessary. I don’t understand why this product is still on the market. (money is why)
        Again, I’m so very sorry for your loss… I pray you get comfort in these times.

  5. Frank says:

    I took our cat Zeus in the day after Christmas because he was having intermittent episodes of vomiting and although he was eating normally it looked as though he was still losing weight. We thought he may have some kind of intestinal parasite but all in all he was in good health. The vet said they wanted to do a blood test and give him some intravenous fluids as they felt he was a bit dehydrated. They also made a passing comment that they wanted to give him an antibiotic as a precautionary step in case he had an infection. The antibiotic they gave him was Convenia. As soon as we got him in the truck to take him home, he immediately started to vomit. We didn’t think much of it as that is why we took him to the vet in the first place. Later that evening he was very antisocial which is unusual for Zeus, but thought he was mad because we took him to the vet, you know how cats are! Over the weekend we notice he was very lethargic and didn’t want anything to do with anyone in the house, even our son who he absolutely adored couldn’t hold him as he wanted to just get away from everyone. To make a long story short, he soon stopped eating and looked like a person who was on drugs and didn’t know where he was. The following Monday, 3 days after his vet visit, I noticed he kept getting up and laying down in different positions as if he was uncomfortable. The following morning we found him hiding under the Christmas tree and meowing in a very pathetic way. He would not eat and just laid in the same place for hours at a time. Later that afternoon I took him back to the vet and told them that whatever they did to him, he was definitely not himself. I was told that he was having kidney failure and they would need to give him an IV overnight. Well, he didn’t even make it through the night! They called early the next morning and said that he had passed away. The only thing I could attribute this sudden death to was the antibiotic shot he received and within 5 minutes of doing a search on the internet I found several posts such as this from Ingrid and quickly realized that our cat suffered the same fate as other cats that had received injections of Convenia. Please, if your vet says they want to give your cat or dog an antibiotic, make sure it is NOT Convenia! I am convinced that this is what killed our cat.

  6. Debi says:

    So sad and frustrating that this keeps happening and the drug is still being given. It’s been almost 2 years now that I lost my precious Cholla to this horrible drug. Both my vet and I reported it to the FDA and Zoetis. Still not even a warning is given to cat guardians of the danger. It must be extremely profitable. How anyone is comfortable profiting from the terrible death these sweet fur babies must endure after a Convenia shot is beyond my comprehension.

  7. EvaServal says:

    My sincere condolences… I wish they’d take this product off the market.
    I wish you comfort and peace in these times.

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