Convenia Injection Chosen Over Oral Antibiotics

Convenia, the long-acting antibiotic injection that maintains antibiotic levels in a dog or cat’s bloodstream for up to two weeks is the hot topic this week.

Let’s look at another case in which Convenia worked out well.

Fritzi is a Shih Tzu who weighs 20 pounds and has a urinary tract infection. A urinalysis revealed that she had round bacteria, cocci,  in her urine. We began an oral antibiotic that has a wide spectrum of effectiveness for cocci, and simultaneously submitted a sample for a bacterial culture and sensitivity test  to a laboratory.

Five days later we had results and the sensitivity portion of the test showed that the antibiotic we first chose was effective.

We called Fritzi’s owner to inform them of the results and to ask them to pick up additional antibiotics so that we could have a total of three weeks of antimicrobial therapy.

They were happy to hear that the organism was not resistant, but had a comment about the medication Fritzi was already on. “She’s been vomiting intermittently since she started it. Not every time, but at least once a day. We tried it with food and on an empty stomach, but nothing made a difference.”

Vomiting, with or without diarrhea, are sometime complaints with oral antibiotic therapy. Many antibiotics are associated with these problems.

We gave Fritzi’s owners three choices:

  1. One was to stick with the same antibiotic but begin giving yogurt several times daily in an attempt to appease the gastrointestinal (GI) tract with beneficial bacteria. The technique works in about 50% of cases and has the advantage of allowing Fritzi to continue to take the same inexpensive antibiotic. Two more weeks of this antibiotic would cost $21.25.
  2. Option two was to change to a different antibiotic. The next best antibiotic infrequently causes GI upset, but costs more. Two weeks for a Fritzi-sized dog costs $61.40.
  3. Option three was to give Fritzi a Convenia injection. The active ingredient in Convenia, cefovecin sodium, is a cousin to the first antibiotic we started for Fritzi, but injectable forms almost never cause GI upset, so we should have excellent results in treatment without side effects. The cost? $65.00

How to decide?

If cost were the only factor it might be worthwhile to try to use the original antibiotic, recognizing that there is a 50% chance that vomiting might continue, which would lead to a change of medication anyway and loss of the $21.25.

Weighing the other two options becomes what modern parlance would call a no-brainer. Two weeks of pills twice daily versus no pills, for almost the same cost?

And nearly identical effectiveness.

While the final decision is always the client’s choice, most people would choose the Convenia injection, I’m sure.

I know I would for my own pet.

See you tomorrow, Dr. Randolph.


  1. Amy says:

    I know this post is several years old, but I wanted to add my story. My cat Mau-Mau is 12 years old. Three weeks ago we took him in for what we thought was an oral abscess: swollen upper lip, green puss in mouth, pain to the touch. Being that this is his time of year to eat mice coming into the house, I figured that was the cause.

    The vet could not find the puncture or head site of the abcess. He went ahead and gave my cat the Convenia injection. It showed up on the bill as 11 doses? I’m assuming that is due to body weight. He also was given an IV of fluids, due to his lack of eating from the mouth pain.

    The first day home he slept due to the anesthesia. The second day he started vomiting clear liquid and foam. The third day, he still had no interest in water or food. I tried feeding him wet food through a syringe and he threw it up within a half hour. I continued for the next few days trying to feed him with a syringe and give him water, but he just couldn’t hold it down.

    I finally called the vet and picked up cans of Hills Prescription Diet A/D canned food, as well as Cerenia 16mg tablets for vomiting. After giving him the Cerenia, he was able to hold down his food for almost 2 days. Then vomiting would start back up. I was able to space the Cerenia tablets out to every other day.

    Let me make it clear, during this past entire 3 weeks, I have had to feed him hourly with a syringe, both food and water. He has zero interest in food, even on Cerenia. If I give him more than one syringe of food/water at a time, he will vomit (even while on Cerenia).

    Sigh. Again. This has been going on for 3 weeks now. On top of his lack of appetite, he is also bound to his bed- meaning all he does is lay down and sleep. I am not sure if the cause, but after reading about Convenia side effects and how long they can last, I’m wondering if that’s the culprit.

    Christmas is almost here and everywhere is closed. I’m going to continue my routine until my vet is open. I think I have only helped him to just get by. Thankfully no yellowing of the ears or eyes! I know they will want to do blood tests. Hopefully they might have a longer acting solution to his nausea and non interest in food/water. Fingers crossed that he will be okay and it’s nothing serious. I call him my little soul mate. It will break my heart if I lose him.

  2. TRic says:

    I am incredibly worried about the Convenia shot after all the scary reviews. I realize these are all from the Internet (pssht) and so are intentionally the bad ones, but it still makes me nervous. My cat Fritz went into the veterinarian’s office 10 days ago and was diagnosed with a UTI (I’m not sure if it was just crystals or if there was actually bacteria involved) but he received the Convenia shot. Before the shot, he was peeing all over the place, had blood in his urine, and was meowing all the time. Since the shot, he has been peeing normally and hasn’t been meowing as much. However, there is a distinct change in his energy level. I took him into an ER veterinarian last night to make sure the UTI hadn’t become a blockage, but they found everything to be normal. Maybe his lethargy comes from just being sick? But there is a distinct difference in the way his eyes look- they are droopy and he seems “spacey.” He also sleeps all. day. long. He is about three years old, and I have never seen him sleep so much before. He is eating a TON (special SO diet- about a can and a half a day: he is a seven lb cat), still peeing normally, and sometimes wants to play, but not often. Is there any reason for me to take him back to the veterinarian? Or should I continue to wait it out?
    Thank you so much for your love of animals!

    • Take a deep breath. Whenever you go online to look up medical information, keep in mind that 64% of the medical information on the Internet is either outdated or just plain wrong. And, that’s not counting the “stuff” that is written by the opinionated, uninformed element. By contrast, when something we’ve published on becomes outdated, we take it down! There is a lot of hoopla about Convenia, but how much has been substantiated by laboratory testing and necropsy? Very little. In the years I’ve administered Convenia for both on-label and off-label uses, I have had ONE (1) bad outcome, which was clearly an allergic reaction, was treated and the patient did great. I have spoken to Pfizer Animal Health (now Zoetis) extensively about the safety parameters of Convenia. They are legally bound by the Federal Food and Drug Administration (FDA) to disclose problems with medications. Usage history simply does not match the vitriol on the Internet. There is no reason to suspect your kitty will have any problems from Convenia. If you would like to read more of what we have posted about Convenia, simply type Convenia into the SEARCH window in the upper right hand corner of this or any page on and press the Enter key. I have written about it extensively because it is a wonderful tool in the veterinarian’s toolbox that does wonders for the vast majority of patients for whom it is used.

      • Barbara Johnson says:

        Convenia saved my dogs life at a fraction of the cost I spent for 2 days of IV antibiotics at a teaching university.

  3. shope says:

    My cat had Convenia injection today at 1pm and he has not had any problems with eating or drinking. Is this a sign he is not going to have all of the reactions other people are talking about?

    • Funny that you would write when you did. A colleague and classmate called me the same day, asking about Convenia. He had never used it, then ordered his first bottle. But, when it arrived he was concerned about some of what he had read on the Internet. His question for me was, “Should I send this back? Is the first cat I give it to going to die?” I assured him that my experience has been completely different from much of what one reads on the Internet. I have had one reaction to Convenia, and it was a typical allergic reaction: hives, redness of the skin and itchiness. It resolved within a few hours after an allergy-blocking injection. Another of our classmates practices near our hospital. We talk at least twice weekly and he has never had a single bad response to Convenia. However, this is the experience of two doctors. Others who have had different experiences need to follow the instructions in this post: Report An Adverse Event. It’s the only valid way to identify true problems with any medication. Most of the negative reports one reads are anecdotal, stories with no gathering of factual, scientific/medical facts. I trust your kitty is doing well, but would like to hear back from you.

    • Lynda S. says:

      Your Convenia comments about the allergic reaction and subsequent good outcome of treatment for one of your patients is good news. However, I am skeptical. My vet said their is no antidote for an allergic reaction to Convenia. Since it remains in the body the patient dies. What did you use to combat that?

      • The bacteria-killing activity lasts 14 days, but the allergic reaction can be stopped with one’s favorite intravenous corticosteroid, with or without an antihistamine. Even though I wrote that post some time back, it remains the only problem case I’ve had with the medication, and we use it a lot. Thanks for reading

  4. Lainey says:

    Dr. Randolph, I had my little boy put to sleep today. I just couldn’t ask him to endure any more. We never really decided he had FIP, but it was obvious he was getting worse and was probably not going to recover. At least he got to spend a little time at home. The weather was rather nice yesterday, so I let him sun himself outside for a few minutes. I think he enjoyed that. I wonder if the Convenia triggered the FIP somehow? I don’t know if it was the right thing to do, but I let Pfizer have his remains for autopsy. I’m not expecting much from it, but I’m hoping they’ll find something to help other animals. I’ve read too many sad stories connected with Convenia injections to believe it’s a coincidence.
    Okay, I’m done here. Thanks again for the kinds words. I guess I did need your sympathy after all.

    • I know you are heartbroken. You did all the right things. Perhaps you would be comforted by visiting this post on grieving. I wrote it after I lost my own cat, Sally, to FIP. She was a totally-indoor cat who probably got the virus through our back porch screen, fighting with stray(s), thus sharing nasal and/or saliva droplets through the screen. She was such a delight, and only 12 years old. That was 1992, and I still miss her. You can have no regrets at this point, because you did everything possible.
      PS: I would love to see the Pfizer report, if you don’t mind sharing it I can send you my mailing address by email.

  5. Lainey says:

    Dr. Randolph, I brought my kitten home yesterday. Wow, nursing a sick cat is difficult! His belly is still big, but his temperature has been normal for several days. The veterinarian is cautiously optimistic; however, she has not ruled out FIP. I’m just hoping he’s not completely miserable, and that being home will have something of a healing effect on him. I didn’t have a question. I just wanted to give you an update. Happy New Year!

    • Lainey, you have been very brave, and very dedicated. My hat is off to you. My heart is breaking along with yours. Thank you for having the courage to “nurse a sick cat.” It is hard work. And thank you for the update. We really like knowing what is going on with pets (and readers) we have bonded with.

  6. Lainey says:

    I’m very sorry to hear about the loss of your patient today and the well-loved pet you lost in July. She was lucky to have you for her human caretaker. I mentioned your response about the textbook FIP to my veterinarian, and she said there are some things about my little guy’s case that are not textbook. She explained what they are, but it’s all pretty much over my head. I was just glad to see him feeling better this evening. We’ll see how things go this weekend. For my part I’m ready for whatever comes. I’d just like to say I think he’s a rather remarkable and charming little cat, and I’m happy to know him. I probably won’t write again, unless something unusual happens. Thanks again for the kinds words and advice.

    • The reason I included the parenthetical phrase “despite not having examined him myself” is that there are things to know when one is not present that can be crucial in a case, which make the difference between knowing when one is a “textbook” case and when it isn’t. From what I can tell your veterinarian is doing an exceptional job, and you are fortunate to have her. Thank you for keeping me updated and I want you to know you can write to us any time at all.

  7. Lainey says:

    Sorry, Dr. Randolph, I don’t understand the thinking here. Why bother to reduce his fever if he’s got a fatal disease? Wouldn’t it be more humane just to have him euthanized? He doesn’t have to hang around for my benefit. And despite that fact that he seems to have a textbook case of FIP, should I give the blood transfusion a chance to do some good? I need advice, doctor, not sympathy. Although I do appreciate the kind words. If he were your cat, what would you do?

    • All you can hope for now is to buy some time. The transfusion may perk him up, the steroids may reduce his fever, the purpose of which is to make him feel better in the hopes that he might eat. Realistically (despite not having examined him myself), a little time is all you can hope for. The only value to that time is to give him and you time to say goodbye. If you feel you’ve already done that, and have already, emotionally, let him go, then there is no good argument against euthanizing him now. What would I do? I can tell you what we did when we had to let our Martha go at the end of July. She lingered for a month, even though I still don’t know how. She drank, but wouldn’t eat. Still, she seemed happy and wasn’t suffering in any way. We prayed with her and for her daily. On her last night I looked for a sign to know whether she was going to “go” on her own or whether she needed my help. Right at bedtime she began to wobble and shake. It was the first physical sign of “disorder” she exhibited. I made the decision to euthanize her at that point. Or, maybe she made the decision. Again, if you feel you’ve said your goodbyes, consult with his doctor and this may be the right time. I’m so sorry. There is never a good time to have to let go of a friend. Christmas just seems like the worst possible time. (I lost a patient of my own today.)

  8. Lainey says:

    Thank you for your comments, Dr. Randolph. The veterinarian has contacted Pfizer. It was one of the first things she did. The test results for autoimmune issues came back negative. She received cytology results today, and the fluid from his abdomen shows high protein levels but no fibrin. I can’t recall if we’ve received any results regarding his liver. She mentioned the PCR, but I think we’re going to give him a few days to see how the transfusion affects him. If he improves we may move on to steroids to help with the fluid. She says his temperature is holding steady at 104.5 and his belly is not much bigger than it was yesterday. If he declines, then she thinks that would be a pretty good indication that he has FIP. So now I guess we wait. What do you think of this plan? I was so upset after reading about FIP, I was ready to have him euthanized this morning. I don’t want him to suffer in any way. He’s been through enough.
    I also wanted to mention he’s not really eating now. I was told he didn’t eat anything during the night, but he had been eating somewhat up to that point. And the fluid in his abdomen is not affecting his breathing, so it’s not so much that it’s crowding his lungs. I’ll be going to visit him in about a half hour. I almost don’t want to disturb him, but the doctor thinks it’s more helpful than harmful.

    • Lainey, I didn’t want to rain on your parade, but if there was ever a “textbook” case of FIP, your baby is it. Steroids are certainly worth a try, and might even break his fever, or at least reduce it. I am so sorry. I know you have been dedicated to him and your words clearly indicate how much you love him.

  9. Lainey says:

    Here’s another Convenia horror story: My kitten, who was a stray, is between 5 and 6 months old. (He’s such a good little guy. Everybody thinks so.) He’s had a few problems, starting with a prolapsed anus, which is why I adopted him in the first place. Once I saw his condition, I had to help him. The veterinarian fixed him right up, no problem. A few weeks later, he was urinating in places other than the litter box. I took him in to the veterinarian, and of course, he had a UTI. The doctor prescribed Clavamox, and the UTI cleared up. But it came back about a month later. More Clavamox (which I forgot to refrigerate one day in the middle of the treatment). When I took him back, he still had some bacteria in his bladder, and the doctor suggested Convenia. She gave him Convenia along with his last FIP vaccine. This was last Friday. By Sunday he was noticeably lethargic and warm, but eating and drinking. I took him back this past Monday. He had a fever of 103, and I told the doctor his tummy seemed a bit swollen, but she couldn’t really tell. She gave him fluids and B vitamins. It didn’t help. I took him back on Tuesday. His temperature was 105 and his belly was still swollen. He’s still there, and so far he’s in a decline. He has become anemic. I don’t really understand everything the doctor tells me, but number relating to his anemia is 21. It was 26 yesterday. She has ordered blood for him, which I hope he will start receiving tomorrow, Friday. Fluid is collecting around his intestines. That’s the reason for the swollen belly. I have been visiting him every day, and he’s very much out of it, but he still purrs quietly. He just wants to sleep. His temperature has dropped a little, 104.5. They’re giving him another antibiotic; I guess because fever indicates infection, but I’m not clear about what the infection is. His kidneys have checked out okay. They’re checking for an autoimmune problem. (He tested negative for Feline Leukemia Virus and Feline Immunodeficiency Virus.) I’m not sure what else I can tell you. What I want to know is, when will we start to see some improvement? I won’t discuss anything less than improvement, so don’t bother giving me any harsh reality lectures, doc. I know he could die. If he’s going to live through this, is it possible for him to show progress before the two week sentence is up? By the way, he hasn’t stopped eating and drinking. And so far he hasn’t vomited. Thanks for your time. I’ll let you know what happens.

    • You should ask your veterinarian to call Pfizer Animal Health and submit an “Adverse Event Report.” Feel free to contact Pfizer Animal Health independently yourself, too, if you’d like, and they will record your observations of your pet. Such cases as yours often require involved workups (diagnostic procedures) as well as long-term supportive therapy until they start to turn around. Laboratory testing is crucial to be able to know all of the organ systems involved in the process. With your baby’s signs, I would also like to see the results of a PCR (Polymerase Chain Reaction) test for feline coronaviruses, specifically Feline Infectious Peritonitis. Thank you for writing and please keep us posted on your pet’s progress. To read more about Convenia, click here. To read about the red blood cell count, click here. To read more about Feline Leukemia Virus, click here. To read more about Feline Immunodeficiency Virus, click here.
      Best wishes, Dr. Randolph.

  10. Carol Andrews says:

    Yesterday I was charged $421.00 for a 80 mg/ml dose for my dog. Is there anything I can do to stop this doctor from ripping us off ? I was also charged $5,000.00 for my dog’s knee surgery and then again to remove the steel plate because of infection and then another $5,000.00 for the other knee. Please give me some advice. Thank you, Carol Andrews
    P.S. No, my dog is not in good shape, he can hardly walk.

    • Carol, this is a matter for you to discuss with your veterinarian. Is he not available? Is he not approachable? Most veterinarians are happy to discuss problems with unhappy clients. Usually it’s a misunderstanding and can be worked out amicably.
      As for the costly injection, I’m unable to comment, as you’ve not indicated what was administered. That your comment appear on a Convenia page and Convenia’s concentration is 80 mg/ml implies that Convenia was given, but, not knowing the body weight of your dog, I have no way of knowing how much Convenia was administered. Veterrinarians are fee to establish their own fee schedules, and Convenia’s injection fee is usually based on body weight.
      You say you spent $5000 on “knee surgery.” but you didn’t specify what kind of “knee surgery” was performed, or, again, what your dog weighs. Surgery on big dogs costs significantly more than small dogs because of the increased cost of anesthesia, time and supplies for the larger patient. That a plate was involved implies that TPLO surgery might have been performed, and that’s an expensive procedure regardless of where it is done or who does it.
      As for the complication requiring plate removal, it’s just one of the complications that can occur after surgery. A friend of mine had his knee replaced. Two years later he was sitting at his desk when he began to have sudden-onset pain and swelling in the knee. Turns out that bacteria from his eczema (a skin condition) had invaded his bloodstream. When the bacteria found the most susceptible tissues in the body, the site of his knee surgery, they made a home and a tremendous complication. The knee implants had to be removed surgically, the infection cleared, then new implants surgically placed.
      It is sad when patients don’t heal as we expect them to, but it is still a fact of the practice of medicine.
      Carol, you asked for advice, and the only advice I can offer is to ask you to visit with your veterinarian and let him know what your grievances are. I hope you will and I hope you will let me know the outcome of your visit.

  11. AlmostHome says:

    I AM being proactive. I took her to ANOTHER doctor. She has seen two doctors in less than 7 days. Let’s say the Convenia IS the cause of her deterioration – tell me what the treatment would be to counteract this long acting antibiotic? There isnt one, is there?

    • Dear Almost Home, I know you’re frustrated, please don’t take your frustration out on me. I’m only trying to help you and help your dog in trouble. I recognize that you have seen two veterinarians in seven days, BUT, what your pet needs now is evaluation for a NEW problem that didn’t exist then. No, there is no antidote or specific anti-Convenia therapy, no chelation that will take it out of her body, but there IS what I mentioned earlier: SUPPORTIVE THERAPY. In order for her supportive therapy to be effective, though, your pet’s doctor needs to know what organ systems are being affected, and how they are being affected. That is determined by the testing I’ve recommended, which constitutes a minimum database. With the problems you’ve described with the rear legs, she may need to see a neurologist. No one knows what the outcome of her case will be, but we do know that she has a much better chance of full recovery as we obtain more information and she has maximum supportive therapy. Thank you for your reply, Dr. Randolph.

  12. AlmostHome says:

    My dog was not ill. It turns out that she was experiencing a prolonged case of reverse sneeze, which I didn’t know anything about at the time and thought was serious due to the fact that it looks like your pet can’t breathe. Apparently small dogs experience this frequently and it is not life-threatening.
    The second veterinarian I took her to did a thorough exam and could find nothing other than the Convenia that could be causing my dog’s symptoms, which, as of this morning, now include weakness in her hind legs! Her legs appear to either lock out or grow weak and slip around. My dog NEVER experienced this prior to one week ago, when she was given the injection. She continues to look extremely sick, especially in her eyes. I KNOW that this is not normal. I am afraid of what tomorrow will bring. I’m sick at the thought that I’m watching her deteriorate day by day. Am I going to lose my dog over something that she never needed in the first place and should never have gotten?
    I plan on calling the original veterinarian to report this in the morning. And then I will report it myself. It’s scary to think that an animal could have a deadly reaction to an antibiotic that continues to harm them for at least 14 days and there is no way to counteract it. I pray that tomorrow brings no new symptoms.

    • Dear Almost Home, While I’m happy to hear that you are following through on the reporting process, that was only one of my recommendations. You ask, Am I going to lose my dog over something that she never needed in the first place and should never have gotten? The answer is that, without a proper diagnosis and treatment, you are much more likely to lose her than if you are proactive. While it is possible that she may get well on her own, do you want to take that chance? I, too, believe in the power of prayer. However, I believe God gave us doctors for a reason, and that reason is to call on them when they’re needed. Right now, your dog needs a doctor, as evidenced by the fact that her symptoms are advancing, not improving. I thank you for your prompt reply and I look forward to updates on her situation. I’m praying for her, too, Dr. Randolph.

  13. AlmostHome says:

    My dog was given a Convenia shot without explaining to me what the possible side effects were or giving me an option of an oral antibiotic. She was given this injection for kennel cough that she does not have (I took her to a second veterinarian as the first did not do a thorough exam and did not listen to me when I tried to explain her symptoms, so I wanted a second opinion). We are on day 7 and my dog grows more and more lethargic. Her eyes are zombie-like and she is not herself. Pet owners KNOW what their pets are like normally, the brightness that usually exists in their eyes. My dog is limp and lifeless and her personality has changed completely. She doesn’t want to be touched when she used to love sitting on laps and petted.
    We have at least 7 more days of this to work through (though, I suspect it will take longer, if she improves at all). I am distraught thinking that she is suffering so unnecessarily as she never needed an antibiotic, let alone such a powerful one! This is just terrible. I am so upset and angry.

    • Dear Almost Home, I feel your pain. Your baby is ill and you want her well. One of the most important things NOT to do at this point is participate in tunnel vision. While you believe that Convenia is at fault, remember that you took her to the doctor in the first place because she was ill. Step One is to have the first veterinarian report an Adverse Event to Pfizer Animal Health. You may make a separate report, if you’d like. Second, or, better yet, simultaneously, take her to a veterinarian you trust and have her examined and sufficient procedures performed to determine the cause of her lethargy, the effects on her body and the necessary treatment. This may include Complete Blood Count, Chemistry Profile, Urinalysis and Chest X-ray. the bottom line is that you want your dog to feel better and to survive this event. Proper treatment depends on an accurate diagnosis and supportive therapy to get through the event, no matter the cause. This is a topic I am extremely interested in and I would greatly appreciate an update as soon as you know more. Best wishes, Dr. Randolph.

    • Christina says:

      AlmostHome–I see that you wrote this almost 7 years ago. A month ago my dog received a shot of Convenia and Cerenia (without my consent) and the next day she was completely ataxic. She was rushed the the emergency animal hospital where they tried to tell me she injured her back legs. I kept arguing with them that there was no way that had happened because she was with me the entire time. After having a seizure while awaiting discharge, they finally admitted her and took my claim seriously. The next day she was moved to her regular vet where she stayed for two days being treated with IV fluids and steroids. She was sent home showing “little progress” and continued to stay on steroids. She began making progress and within 3 days it was like a miracle had happened. When I brought her back to the vet they couldn’t believe that she was OK and were surprised. We began weaning her off of the steroids and when it came time to skip a day, she was set back beginning to have problems walking again and she didn’t want to be touched–almost as though it was painful. Her vet put her back on the steroids and a pain reliever. We now four weeks since she has had the Convenia and Cerenia injections (which both claim adverse side effects consisting of neurological and ataxia). She is scheduled to see a neurologist on Monday, but to be honest I am so scared that the effects are not reversible. The timing is terrible as I am 8 months pregnant and now more than $2,000 deep in vet bills trying to save my baby. Please let me know if your dog recovered and what treatments were used. I am desperate for answers, but through research seem to come up empty. I initiated the report with Zoetis, but they have been no help in releasing information on the adverse effects). Any help is appreciated.

  14. MJ says:

    I think this killed my cat. She was at the veterinarian for vomiting and dehydration so she was given fluids and IV antibiotics. When she was stable and hydrated she was alert and purring and ready to try it at home. Just before we took her home, the veterinarian administered this two-week antibiotic. Within an hour at home she couldn’t breathe and had gasping breaths. Despite returning to the veterinarian and receiving oxygen, she couldn’t recover because the drug was still being absorbed. She had to be intubated and eventually we had to let her go since she could no longer breathe for herself. It was traumatic to watch her struggle to live and not be able to do anything about it. It just seems like she was recovering until they gave her that antibiotic. I would advise against it and just give oral meds because it’s not worth the risk.

    • MJ, please accept our sympathy for the loss of your kitty. If you are a regular reader you know that our family has recently lost our Pearl and our Martha, so we are right there in the boat you are rowing. One of the most important factors to consider when an ill pet dies is that she was sick in the first place. Something made her ill, or she wouldn’t have needed medication. Certainly it is possible that she had a reaction to the Convenia. Any medication can cause a reaction. Usually patients respond to the kind of aggressive treatment you describe being administered to support her and reverse the reaction. To lose a patient under those circumstances is fairly unusual. Still, there are many other factors that could have caused her death, and only a detailed (and expensive) necropsy would have given you the answer to the cause of her death. In Sympathy, Dr. Randolph.

  15. Kat says:

    My 2-year-old cat had a URI that was not clearing up after 2 weeks and sneezing violently. He received a shot of Convenia on 7/14/11 against my better judgment, I was concerned about it being on board for so long if he had any adverse reaction, but the veterinarian said if anything happened “we can give him steroids.” He lay around like a limp rag for a week and was drinking water voraciously. I took him to a different veterinarian who did lab work and his creatinine is elevated at 2.6. He said he “doesn’t know if it’s related to Convenia or not.” He was given some subcutaneous fluids. His urine specific gravity was normal. He received the shot 16 days ago and still is not himself. He was a non-stop active 2-year-old, and now he moves around like he is 15. I wish to God I’d never let him receive that shot.

    • It’s a sad fact of the practice of medicine that sometimes bad events will occur despite the best efforts of the doctor, patient and pet owner. Sometimes there are factors in a patient’s illness that cause problems and are actually not medication-related at all. Major pharmaceutical companies, such as Pfizer, have departments to investigate unexpected events such as this. Please ask your pet’s doctors to report this to Pfizer Animal Health for further investigation.

  16. Lynn says:

    Hi. Two of my cats have also had Convenia injections. Both were for wounds that abscessed (they’re very pampered barn cats … up to date on all vaccinations, spayed, neutered, etc. but, they roam and get into things, lol) The Convenia worked fabulously well for both cats. My only complaint is the cost! I’ve spent $400 in vet visits in the past three months for abscesses antibiotics for these two … the shot is like $45 then there’s the office visit, and the antiinflammatory injection. I wish I could just keep it on hand, lol.

  17. Sandy Altman says:

    Two of my cats have had Convenia injections. Psycho has had it twice. In fact she had one about an hour ago. The other was in November of 2010. Psycho had no problems at all with it. Isis had it 7 days ago for a respiratory issue. Cleared her up in a couple of days. Had no problems with the Convenia at all at any time.

  18. Ann Heatherton says:

    Two different veterinarians have used Convenia on two different cats of mine. One cat , Missy, was very sick with an upper respiratory tract infection (coughing up mucus) and also suffered from stomatitis. She was given the Convenia shot and that put her on the road to health. The second kitty, Sage, was given a Convenia shot Friday and so far she’s doing great. No problems. And I expect she will recover from her bacterial infection shortly. When you have semi-feral or very uncooperative kitties, it’s wonderful to have a long-acting injection like that.

  19. Ann McKenna says:

    Thanks for the reply. I contacted the veterinarian’s secretary, who in turn listened to all I had to say and informed her that Misty was due for surgery the next day. Thus I was asked to wait on the phone for 2 minutes, secretary didn’t come back on the phone but rather Mistys’ veterinarian. She asked what was happening and I related the shaking and the “snore like” sounds she was making. Well, the veterinarian said, “You know what, if Misty has the growths removed tomorrow or in 3 weeks, it won’t make a difference. If I felt it was urgent I’d say so.” So veterinarian cancelled Friday’s surgery telling me to watch Misty and if she should get worse to come either Friday or Saturday and if not, to call midweek to rebook the surgery. So as it stands now Misty is eating well, no shakes and doing fine. So I guess she’ll have the 2 little growths removed mid month and I will post once that happens. Once again thanks for this site and for replying 🙂

    • How wonderful to have a caring, considerate, flexible and respectful veterinarian. Often, “Moms know,” and I find myself respecting owners’ wishes when it comes to their opinion of what is right and when for their pets. Thank you for the update and we look forward to a post-operative report. Best wishes, Dr. Randolph

  20. Ann McKenna says:

    My dog was diagnosed with a skin infection. She was given a dose by injection of Convenia Monday past and she seems more tired then usual and today noticed she makes a weird sound when asleep ( like snoring but weirder) and just now was on my lap and started to shake. Is this a side effect of Convenia? Tomorrow, and this is why I’m worried, she’s having surgery to remove 2 growths on the nipple area. Will she be ok or should I postpone the surgery?

    • I’m sorry, Ms. McKenna, but these are questions to which only your treating veterinarian has the answers. DO keep us posted on her progress, though, and how her surgery goes. Best wishes, Dr. Randolph

  21. Debra Barnes says:

    My dog has allergies. We have been on several different meds from antibiotics to steroids and back again. She was tested for Cushings five years ago. The radiologist who performed the ultrasound told me she definitely had it. When I returned to my veterinarian’s office, she felt it was a benign growth on my dog’s heart. No further tests were done. We have battled the “allergy” game for 5 years. The veterinarian said he would give her a shot of a new medication. Unfortunately he didn’t tell me the price. $350 dollars for one shot! I don’t have that kind of money but had no choice because he had given her the shot already. Is this a normal price for a dog weighing 80 pounds? She is 10 years old.

    • Debby, we’re going to need a little more information. “Shot” is a vague term that implies an injection. Some “shots” are worth $350, some are worth only $10. What determines the “shot’s” worth is what’s in the syringe. What was in the syringe for which you were charged $350? Second, if a board-certified veterinary radiologist saw a malignant growth on your dog’s adrenal glands and diagnosed Cushing’s disease, he was very confident. However, the adrenal gland and the heart are fairly-well separated from each other, so it would be difficult to confuse the two. I know of no benign cardiac growths that can simulate Cushing’s disease. And, I’m pretty sure the survival time for that type of cancer is much, much shorter than five years. There must be some confusion somewhere. Third, allergies, and all of the complications that accompany them, are a never-ending problem. If you are unhappy with your dog’s status you may wish to ask to be referred to a board-certified veterinary dermatologist. Veterinary dermatologists are also experts in Cushing’s Disease. We will be happy to try to help further if you can supply clarifying information on the above areas. Best wishes, Dr. Randolph.

  22. R. Long says:

    Does Cushing’s need to be treated if there are no annoying symptoms? My dog was diagnosed with the disease and put on Lysodren. Not only was it difficult to get her to take it, the medication was very expensive. I stopped giving her the medication, and can see no difference in her. She has had blood tests that show she is not doing badly. Do animals live longer that are treated? She will be 14 in October.

  23. mdabbot says:

    I took my cat to the vet for a runny nose. diagnosed with an infection, received a convenia shot. Within 2 days, she lost most of her motor funtion, ability to swollow, walk, eat, etc. She gets worse by the week and now 2,300 into vet bills on week 3, she is no better. We put in a feeding tube and changed her antibiotics and though the infection is better, she still can’t swollow or walk right. Something is up with this drug as there are stories all over the internet and all you get from the vets is “well, I’ve never experienced any problems,” towing the Pfizer company line. With all the commentary about this stuff, the math does not add up. I will post on progress. Cat at vet again today doing more testing for some vague problem they have yet to root cause because of course it must be anything else other than the medicine, right.

    • Please read this post to understand why there are “stories all over the Internet.” . For the life of me I can’t conjure up a reason a veterinarian would toe “the Pfizer line” unless he worked for Pfizer. Do I love Pfizer? I have no reason to. Am I happy that Pfizer has made some fabulously-effective medications that have saved untold suffering? Absolutely! Nothing Pfizer, or any other pharmaceutical company does buys my loyalty or protection. You sound like a perfect candidate for a second opinion, and if your kitty is not now in the hands of a board-certified veterinary internist, you might want to consider taking him to one. I certainly hope your kitty makes a full recovery and we will be very grateful for updates. For more information on Convenia you may wish to read this post, ( ) as well as use the search term “Convenia” in the search pane of our home page, ( ) Best wishes, Dr. Randolph.

  24. My dog got a Convenia injection almost two weeks ago and she has shown all the signs of and symptoms of Cushings disease. It has been pitiful to watch her. She drinks continually and urinates every few minutes. I had a dog die of this disease and am terrified that I permitted the veterinarian to give her something to make her so miserable. I am heart sick watching her. Always check the side effects or ask before letting a veterinarian put your dog at risk.

    • WHOAAAAA!!!! Sharon, I’ve seen some far-fetched conclusions reached by loooooooooooooonnnnnnnnnnnnnnggggggggggg assumptions, but your comment reeks of misinformation. One, there is NO WAY that Convenia is going to wipe out adrenal glands, thus causing Cushing’s Disease ( ). Two, by the time you finish medical school you will be amazed at the length of the list of conditions that cause a pet to “drink continually and urinate every few minutes.” Please, do not delay, be on your pet’s doctor’s doorstep when he opens tomorrow morning, have your dog lab-prepped ( ) and find out the real reason she’s having these difficulties. While there is a small chance that Cushing’s Disease is the culprit, the signs usually don’t arrive as suddenly as you have described. And, please, recognize that readers and I will be on the edge of our seats waiting to find out the test results, so let us know right away. Best wishes, Dr. Randolph.

  25. Linda S says:

    We took our healthy 14 yr old Siamese Mix girl to the emergency veterinarian on July 2, 2010, because of an ingrown toenail. Doctor cleansed the area, clipped all the cat’s nails (without asking us), then gave an injection of Convenia for infection. Our cat stopped eating, drinking, and she was experiencing respiratory distress. Brought her back to the doctor who said her chest cavity was filled with fluid from stress on heart. She died today, July 11, 2010. The doctor didn’t warn me of possible side effects. This drug has got to go.

    • Please accept our sincere sympathy for the loss of your kitty. We know how tragic it is to love a cat to 14 years of age, only to lose it. Before we petition the FDA to remove Convenia from the market, let’s look at your cat’s passing scientifically. Recognize that a 14-year-old cat can have MANY pre-existing conditions that could be fatal. Indeed, a pre-existing heart condition in a 14-year-old would not be uncommon. In cats there are MANY different kinds of heart disease, some of which do not show signs on the physical examination until they are advanced. There could easily have been problems with her heart on July 2 that just didn’t show themselves on the physical examination. Please note that in the safety information for Convenia there is no contraindication for use in patients with heart disease and no complaints of cardiac damage are mentioned in the precautions. If such problems existed with Convenia, the FDA would require that they be listed. I have said many times on this blog, “There is no such thing as a 100% safe drug.” [ ] This, however, does not seem to a matter of Convenia safety. We cannot deprive the pet-loving public of a safe, effective medication that has the potential to save millions of lives. Convenia, is, absolutely, a wonder drug. Just ask the people who can’t give pills to their pets for infections. Some other aspects of your kitty’s care that could be investigated include, “What were the results of Complete Blood Count, Chemistry Profile and Urinalysis results?” “What else transpired and what treatment was given between July 2 and July 11?” As for what we have here, there is no evidence that Convenia was a factor. Still, I’m sorry that you have suffered this loss, Dr. Randolph.

  26. terry says:

    We took our dog for her yearly check and the doctor gave her a shot of Convenia for skin irration and told us their was no reaction to Convenia. On Monday evening our dog was limp. By Tuesday she was not eating and just lying around. I picked her up and lay her on my lap. I kept patting her and she seemed to be comfortable. Next she was seizing then died in my arms. I am so lost as to what happened and wondered if I should go to the company for answers. Went on the site and realized that many cats and dogs had the same problems and have died.

    • Terry, our hearts go out to you. Your grief and disbelief are reasons for deep heartache. Let me describe a similar situation I faced today. A client called me and said his dog was vomiting on the medication I’d dispensed. He said he didn’t know he was supposed to give it on a full stomach (he had read online somewhere that he should). I explained to him that I intentionally don’t tell pet owners one way or the other to give it on a full or empty stomach, or even that it can cause vomiting, diarrhea and loss of appetite. Why? Because I don’t want to put the notion into clients’ heads that they might have that difficulty, when, in fact, a minority of pets do. Similarly. a client asked me today what side effects she should expect from the Convenia injection I gave today. In her case I told her what the reported possible side effects were, following that with the comment that I’d never seen any of those problems. Your doctor chose a route similar to the approach I use with that certain oral medication, probably because he, too, sees few problems with Convenia. Keep in mind that there are many, many, many possible problems that can result in lethargy, collapse and seizures other than Convenia. Having said that, I would encourage you to speak to your pet’s doctor and ask him to file an adverse reaction report with Pfizer. Please accept our sympathy on the occassion of your loss, Dr. Randolph.

  27. Karen R says:

    I took my 7 year old, normally-robust cat to veterinarian last week, with a suspected fungal infection on an ear. Cultured, and given Conofite to apply topically. Was due for Rabies vaccine, that was given, along with a shot of Convenia. Within a day, she was sneezing horribly, lethargic, lacking appetite, “spaced out”. This has gone on for 4 days now. Then last night and this morning, I noticed her tremoring slightly. I know there could be a million things to attribute this to, but how strange that she was bouncing around like normal before I brought her in, and less than 24 hours after visit, was showing these symptoms. BTW, she is an indoor-only cat. Any thoughts on the wonder vaccine?

    • As you say, there are a jillion things that could cause the upper respiratory tract signs that you describe. The likelihood of the vaccine being associated with those signs is minimal, as is the likelihood of the Convenia and Conofite being a factor. I would certainly, at the least, be in touch with my veterinarian to see if he recommends a followup. Please let us know what you find out.

  28. Yvonne Drew says:

    My dog just had the Convenia injection. She has not been herslf since. Will not eat or drink water. Just lays around. Is this normal after this injection?

    • Lying around and not eating are never normal. Several possibilities exist: (1) This could be an effect from the disease process for which she was being treated with Convenia. (2) There could be a whole new problem that is causing these signs. (3) While it rarely happens, the package insert for Convenia does mention that some patients will have inappetence. The bottom line is that you at least need to be in touch with your pet’s doctor to see if (1) is the most likely explanation or whether she needs to be seen for this. Your biggest concern is going to be the possiblity of dehydration and complications that could land you in the emergency hospital during the upcoming weekend. Please keep us posted. Best wishes, Dr. Randolph.


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