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More Veterinary Medical Misinformation – This Time Convenia


I am not exactly sure how this got started, but the long acting antibiotic Convenia is the latest veterinary medical sensational tale of conspiracy, cover up, and mass hysteria.  It seems that is traces back to an actual veterinarian and author of a blog and website called, named Dr. Lisa Pierson, who wrote an article called “Convenia, Worth The Risk?”  In this article, she writes of the dire consequences of adverse reaction to the antibiotic Convenia due to its long acting properties that keep it active in tissues for a prolonged period of time.

Convenia was launched by Pfizer Animal Health (now Zoetis) in 2008 as the only antibiotic of its kind: a one-time injection that exerts its antibacterial effects for up to 14 days, effectively eliminating the need for owners to have to orally medicate cats and dogs sick with infections.  In a class of antibiotics called third generation cephalosporins, effective against bacteria that commonly cause skin infections, upper respiratory infections, and urinary bladder infections, Convenia also had impressive FDA safety data.

Most importantly, it promised veterinarians something was very infrequently get…100% owner compliance with treatment.  Compliance is the veterinarian’s single greatest challenge to effectively managing disease in dogs and cats.  Poor compliance is sometimes the fault of the owner, such as forgetting to administer a dose here or there, or my favorite, stopping treatment the moment the pet seems better, to stash the rest of the antibiotic left over to use another day should the pet become sick again (and they can avoid the inconvenience and expense of another vet visit).  Compliance issues are often not the fault of the owner, with pets (namely cats and small dogs) that can be very difficult to orally medicate, or get GI upset from the administration of oral antibiotics.

Many veterinarians have used Convenia for over 7 years with not only excellent success rates due to a wide spectrum of antibacterial coverage and the elimination of owner compliance issues, but also very good safety.  In all of these years, I have only seen one case of an adverse side effect that is possibly attributable to Convenia administration: a cat I was treating for cystitis that became a bit listless and lethargic for a couple of days after the injection.  The question remained, however, was it from the Convenia, or was the cat simply lethargic from his disease and it took 3 days of Convenia therapy to begin to make him feel better?  Since I could not prove it one way or the other, I put a “No Convenia” alert on this patient’s medical account, since I do not deem it wise to tempt fate and use it on him again.

For the 10’s of 1000’s of other injections I have administered since its inception, Convenia has proved very safe.  My veterinary colleagues both locally and around the country have had a similar experience.   In direct answer the question posed by the title of Dr. Pierson’s article, “Convenia, Is It Worth The Risk?”  My answer with one having only experienced one non-serious side effect (and questionably linked to Convenia) noted in 7 plus years of use and thousands of injections administered, absolutely!

Reading on in Dr. Pierson’s website, I also see that she is against therapeutic diets, integral tools for the management of kidney failure, pancreatic, liver, and other chronic diseases in dogs and cats.  This and several other articles I read on her website from my perspective significantly question her opinions and credibility.

However, the word is out, and the damage is done.  Dr. Pierson being an actual veterinarian is making this particular wave of misinformation particularly difficult to refute, with an antibiotic that is particularly important in veterinary medicine for the management of infections in dogs and cats.  To many pet owners, Convenia is now the devil, and more a tool of sickness and death that it is an important therapeutic tool for veterinary patients.  Please see my next article below read about two troubling cases I recently managed that dealt with the aftermath of current unsubstantiated anti-Convenia sentiments.

The Troubling Aftermath Of Veterinary Misinformation – This Time Convenia

Dr. Roger Welton is the President of Maybeck Animal Hospital in West Melbourne, FL, Chief Editor of the Veterinary Advice and Information Website, Web-DVM, and founder/CEO of Dr. Roger’s Holistic Veterinary Care.

76 thoughts on “More Veterinary Medical Misinformation – This Time Convenia

  1. David Cornett says:

    As an owner of several cats who have used convenia. I can attest that it is often very effective. However, after one of my cats that had an abscess and was otherwise perfectly healthy died three hours after the shot, I will not use this product again unless nothing else has worked. I reported the death to Zoetis and they said “It happens in rare cases”. They would not give me an exact number or %. no where on the drug insert is it mentioned that death is a possible side effect, or hemalytic anemia for that matter. I also filed a report with the FDA. Convenia should only be used it you don’t mind that your cat might die and you have tried every other possibility. That Dr. Roger Walton dismissed this as a conspiracy tail and attacked the credibility of the vet that has brought this to our attention, makes me question his credibility. There is a website with a growing number of complaints about this drug which has personally brought me a great deal of grief. No conspiracy just facts. Vets should warn clients before giving this drug. If mine had my cat, Yani, would still be alive today. Zoetis needs to list death prominently as a possible side effect.

    • Dr. Roger says:

      After literally thousands of injections over the past 7 years, I have only seen one case of lethargy in a cat following a Convenia injection. That level of safety statistically makes it safer than any other antibiotic on the market that is used for felines. Any medication at any time can randomly adversely react with any patient at any time, reactions that can lead to death. Thus, if you think that we should warn of the extremely rare possibility of death prior to giving an injection, then we should give the same warning for just about every other medication we use to treat feline illness.

      Let’s put in in this perspective…a person more likely to die from taking a dose of an OTC pain reliever like Advil or Aleve, than a cat is from an injection of Convenia.

      • Laurie bartkoskiartkoski says:

        My cat died 3 hours ago from this damn drug! She was a healthy cat! She had a uti but on her death the dr did an X-ray affirming her health. She was seen prior to our move 2 weeks ago a lively and healthy cat. This drug caused her death and we received no warning. HOW MUCH IS A PETS LOVE WORTH!?

      • Brian Lohman says:

        Our 12yr old simmense sassy was given Covenia 72 hrs ago for a respiratory inflection and is now having labored breathing and is not going to make much longer…

        I’ll give an update to see if she pulls through..

      • Sandra Ducker says:

        My vet gave my dog convenia injection for an infected cyst. I left him for a couple of hours while I went shopping. I came home to find vomit all over the floor and he was severely salivating. I thought it could be anxiety although he has reacted before to drugs. He has not eaten or drank all night. I have been trying to dropper feed him water. I did some research and discovered how dangerous this drug is. I was not told about the side effects and dangers, otherwise I would never have consented. I don’t care what you say, this drug is not safe and the client’s should be made aware of this horrible dangerous drug

    • P. Stuyvesant says:

      So, your cat had an illness prior to being given Convenia; and several other cat of yours have received Convenia without ill effect; and, yet, Convenia is the reason your one cat died. Post hoc ergo propter hoc. I’m sorry for your loss but you need to recognize your cognitive dissonance and get intellectually honest.

      • James says:

        It shouldn’t matter that the risk is only 1 in a trillion. It’s still a possibility, therefore it should be listed as so. People are so quick to say things like ” so you think we need to mention it if only 1 out of 7000 cats died from it” did you ever stop to think that the 1 cat that died meant more to its owner than the other 7000 they’d never seen? If it was found to be the cause of a persons pets death and was not listed as a possibility,even if it was only 1 in 7000, the drug manufacturers had better hope im not on the jury during a lawsuit against them.

      • lil chuckie says:

        You must be Captain Stupid. Why don’t you take a shot & inject yourself with the drug you love & support so much, called Convenia. If it is safe for animals(which is how all drugs are tested before its administered to humans)then its safe for you. Slam it on up and enjoy.

    • Toni says:

      I completely AGREE with you! I have reported to Zoetis and the FDA the incident I had recently. My 15 year old female cat had been drinking a lot of water and urinating more than normal for some time. Had done blood work twice that showed al was in the normal range but vet was not able to get a urine sample from her. Finally, I was able to get one and she was diagnosed with a bladder infection. The vet gave her an injection of Convenia since she is extremely difficult for me to pill. With a follow up 2 weeks later, something was still wrong and I noticed her twitching. The vet gave her a second injection of Convenia with another follow up for 2 weeks. After we got home my cat made it clear to me what was going on. She jumped up in my lap and looked at me showing me how her head was twitching. She was having a seizure! She had Convenia about 4 years before for a tooth infection, but I had never seen her do this before. Since she is old I thought it might just be from having the infection for some time. I did some research on the Drug websites on the Internet and found that it could most certainly be a reaction to the Convenia. NOT just Internet hysteria. Since that is almost exactly when it started, I refused the 3rd injection the vet wanted to give her at her follow up. I told the vet about the seizures that seem quick, but now her entire body twitches. It seems to happen at the very least once every day. More blood work was done and now it seems she has pancreatitis with specific fPL of over 10. I strongly believe this drug has caused the seizures and quite possibly the pancreatitis, a serious disease. While I can certainly understand the need for a medication like this for cats, people should be warned about the possible consequences of the “convenience” of this antibiotic. It should have a strong warning on the label that vets are required to disclose!

      • Dr. Roger says:


        Possible proven adverse effects are listed on all dispensed medication labels and the most common ones are expressed verbally upon dispensation. Any medication has possible side effects. Even certain foods consumed by certain individuals can have serious side effects.

        Here is a very accurate source of the rare but possible side effects of Convenia:

        You will note that seizures and pancreatitis have not been observed. On the other hand, pancreatitis is exceedingly common in cats…I diagnose 2-3 cases per week in cats that have never had a single dose of Convenia. Pacreatitis is so common in cats because of their unique anatomy in the upper small intestine with their hepatic duct (liver duct), bile duct, and pancreatic duct existing in close proximity (we call this the portal triad). Thus, inflammation of infection of the proximal gut, which is very common in cats, commonly leads to disease of the liver/pancreas/gall bladder system.

        Our general bloodwork actually does a poor job of detecting paanreatitis, as pancreatic enzymes in general blood chemistries are well known too be poor diagnostic indicators of pancreas health in cats. Thus, I am willing bet that the pancreatitis was the original issues and it was missed in general bloodwork from the outset of your cat’s illness.

        For this reason, for any sick cat that come in my office, in addition to general bloodwork, we recommend the fPLI test, a far more sensitive detector of pancreatic disease than pancreatic enzymes seen on routine blood chemistries.

        I am sorry for your loss. Based on the detailed history you provided, however, it is far more likely that your cat passed from pancreatitis that went undetected for too long as opposed the the two Convenia injections he received.

        Best regards,

        Dr. Roger

        • Janet says:

          Hello Dr. Roger. My vet has used Covenia on many of my cats. I do animal rescue and kept the ones nobody else would adopt. Of course it’s impossible to mediate several times a day. My vet has used Covenia on the cats with stomatitis. I couldn’t keep forcing Clindamycin pills down their throats. This medicine worked for all my cats. None of them got sick from this shot.

    • Nina says:

      Dear dr,

      Every drug is safe until it is unsafe. We see this all the time. My cat died from Convenia. Period. He was healthy and just had a small tumor on his lip which was causing occasional bloody sneezes. He had full blood work prior to receiving the injection as well as X-rays. Nothing abnormal. Several hrs after he received Convenia, he died quickly and violently.
      My biggest issue with you, dr, and other vets i have spoken with is the amount of CONDESCENSION when you are questioned: “you can’t believe everything you read on the Internet”, “if you google any drug you’ll see people blaming deaths on it”, “people looking to blame death on something”. Its gotten so bad that I even preface the discussion by saying, “I’m not retarded, prone to conspiracy theories and I AM science minded and vaccinate my children so please don’t be patronizing” and I still get the eye rolls. It’s truly sickening that you won’t even consider that something might be going on when faced with so many similar stories. There are Facebook pages devoted to Convenia horror stories. Amoxicillin, no. Augmentin, no. Convenia, scores. I don’t care if you’ve used the drug 1000s of times with no negative reaction. I have read 100s of death stories. And these were not pets with serious illnesses who were expected to POSSIBLY DIE horrible violent deaths in a few hours.
      Convenia has absolutely FACTORED in the deaths. I am not saying Convenia causes death but it was the cause of many deaths. If you are a compassionate, educated person you would question what is going on and Convenias role in it. And the vet you mentioned is not the only vet who is starting to see a connection. I, personally, have spoken with 2 vets in the Chicago area who are aware of the deaths and will not use the medication because, although they won’t say what is going on, they refuse to ignore what you could give two shits about.
      So for Sherman, Jake, Angelina, Baby, Molly, Sheldon, Sean, Zinnia, Juniper, Papaya, Fauna, Basil, Max, Chrissy and all the rest: FUCK YOU!

  2. Chris Whitley says:

    You need to Google all the adverse reactions to Convenia – it us shocking! Search anemia and Convenia! Very eye opening. My vet used this one of my cats and one of my dogs and they were fine. However a friend of mine now has a dog with INMH and severely sick amend may not live. The ER has ruled everything else out. I will never let my vet use this again. And remember no-one believed pet owners when they said that the Chinese chicken jerky and food was poisoning their pets!

    • P. Stuyvesant says:

      You should Google Sasquatch sightings — it is shocking. What is INHM and severely sick amend? And the ER has ruled everything out? Was it a spet you spoke to? Your attempt at logic is frightening. And your attempt at writing a concise case history is pathetic.

      • Sasquatch says:

        no drug Has EVER been proven to cause deaths after it has been used safely for years and approved by the fda. No drug has ever been recalled. None. And Vets are always right and people in general are alarmist idiots who believe everything they read. Yes, 100s of healthy animals should be expected to possibly die horrible deaths hours afyer coincidentally receiving Convenia. Totally normal. Occam’s razor is silly.

    • Dr. Roger says:


      Here is a very reliable and accurate source for the known rare but possible adverse effects of Convenia in dogs and cats. Please note that anemia is not one of them:

      INMH is mot a disease I am aware of, so perhaps you meant IMHA since you are discussing anemia? IMHA is an autoimmune disease where the body’s own immune system targets its own red blood cells for destruction leading to anemia, in some cases life threatening. This disease occurs most commonly for genetic reasons and occasionally as the secondary result of cancer or tick born infection.

      It is disappointing when people put more credence in Dr. Google than an extensively trained and experienced veterinarian.

      An for the record, I have been reporting on the Chinese jerky treat link to illness and death in dogs for years.

      Best regards,

      Dr. Roger

      • THEE KAREN says:

        Anemia IS ABSOLUTELY AN ADVERSE REACTION. My cat died from it, you blind idiot. You’re not a “doctor.” You’re a money hungry parasite pushing this crap on pets because you know it’s the one way to get them back in your office when they’re dying a painful death, and then you’ll get the money on the euthanasia. You sicken me. You sound about 20 years old, uneducated, and sarcastic. You’re lucky I don’t know how to find you because I would destroy your practice and cost you everything the way you dirty uneducated parasites costed me my cats life. Let me find out who you are. I will make sure everyone knows you promote a death shot. Sociopath.

  3. DFS says:

    There are now hundreds of people who lost their pets to Convenia- I don’t believe you haven’t observed a reaction to it after thousands of injections. You have not drawn correlative evidence because you are not looking for it. How many animals develop major organ issues within 6 months-1 year after Convenia? There are hundreds of animals killed by this drug, my dog was one of them. Vets inject it off label with no evidence of specific infection, and not considering the specific health issues of the animal. But young and old, otherwise healthy animals are dying painful deaths. I join the others to get this drug off the market and force veterinarians to look deeper at long tern effects and stop passing the buck onto unknown, guessed at conditions that were unknown. You can’t attribute pet deaths to conditions you didn’t know existed. You can readily draw the correlation of Convenia and it’s complications and the cascade of adverse events that precede death, and , eerily, tell almost the exact same chain of events in the majority of animals. If the veterinarian community will not make itself accountable for these deaths, then pet owners will inform each other to watch out for this insidious drug. Our animals deserved this much consideration.

    • P. Stuyvesant says:

      First, correlation is not causation; but you likely would not know that. Second, please list the hundreds of people who have lost pets to Convenia and cite the clinicopathologic evidence of Convenia being the cause. Third, please cite the evidence that Convenia causes organ damage. Fourth, please define ‘off label’ use in terms of an antibiotic. Fifth, please explain how you can’t attribute ‘unknown’ conditions to a pet’s death but you can to Convenia. Sixth, please expand on this alleged well known ‘cascade of events’ that precede death due to Convenia. Seventh, please educate yourself before spouting drivel of which you haven’t the slightest clue.

      • Sasquatch says:

        Substitute: Thalidomide, Accutane, Duract, Fen-Fen, Raplon, Rezulin or Zelmid for Convenia. Oh and lobotomies, too. Drugs are tested, approved by the FDA, bad shit starts happening, public outcry, public ignored and called stupid, years go by, lawsuits filed, drugs proven dangerous, pulled from market. Thaliodomide babies are just whiny assholes.

      • Sean D Neves says:

        Tell me why there aren’t these types of upheavals about any other drug? It is being overused by lazy vets as a catch all. Add my kitten to the list. Dead three days after Convenia. Ataxia, total nervous system collapse.

        • Carol McD says:

          I keep trying to comment to this thread, but keep being kicked off. We’ll see if this works.

          What Sean Neves describes is exactly what happened to my kitty last Sunday night – one week ago. Only it wasn’t days later that the collapse occurred. It was 12 hours after injection.

          I will probably never know whether Convenia caused her collapse. It is suspected that she had a serious underlying disease – a possible tumor. But I can’t shake the idea, which was my initial reaction, that she had an adverse reaction to the injection of Convenia. Three vets said, “no,” but that was my immediate response when she collapsed. It has a cause and effect appearance in my mind. Her symptoms seemed to appear suddenly and her decline happened suddenly. Maybe that was a better way to die than dragging out for months, I don’t know. I am suffering, and don’t know if her death ever could have not caused that. She was a sweet, funny and beautiful companion.

      • THEE KAREN says:

        P. Stuyvesant: You’re mixing that Xanax with Johnny Walker again, huh? You are too lazy to go on Facebook and look up CONVENIA ADVERSE REACTIONS and see all the stories, you fucking parasite? I’m betting you also tell your “patient’s” parents there’s no hope so you can lust over watching them die when you euthanize them too. You probably dream about the thrill of the kill and get off on it, you fn psychopath. Save your bullshit. You’re just another lowlife “Vet student” or ass-wiping vet tech with a cheap certification begging for the world to recognize you as educated. You’re lower than trash. Learn to use a simple Google search: CONVENIA ADVERSE REACTIONS ON FACEBOOK. Hopefully you’re far away from animals by now and working at Home Depot in the stock room where you belong, you piece of shit.

    • Dr. Roger says:

      Both initial FDA approval and extensive retroactive data going back over 8 years, refute all of your statements. Criticism of off label use really makes no sense. FDA trials are expensive, so antibiotics are often subjected to proving the clearance of infections in just one or a few organ systems.

      In the case of Convenia, a third generation cephalosporin, it made sense to choose skin infections, since cephalosporins are particularly effective for bacteria that infect the skin. However, given our knowledge of the pharmacology and bacterial coverage afforded by cephalosporins, we know that they are also effective against upper respiratory infection and urinary tract infections. In pets that have infections where the owner cannot orally medicate, it is our ONLY option to treat.

      Thus, off-label use has nothing to do with the safety of a medication, but what the FDA approved it for, which is why off label use if any number of medications is very common in both human and veterinary medicine.

      As far as not looking for reactions? As I stated in other threads, my American Animal Hospital Association (AAHA) accredited hospital fosters a strong doctor-client-patient relationship. Every patient that receives treatment for illness or has surgery, receives a medical progress call within one day from a member of my medical team. Clients are encouraged to call any time with questions or concerns about the health status of their pets and my doctors and I always either take the call or call back at our first opportunity.

      Among the hundreds of cases of pets that you describe lost their pets to Convenia, I would ask, how many of these hundreds had post mortem examinations (necropsy) to prove that death was attributable to Convenia? What disease process or processes were in place when Convenia was administered?

      We live in an age of increasing bacterial resistance to antibiotics, which makes it plausible that some of these pets may have died of their infection despite Convenia and because of it.

      In the real medical world, treatment does not always work and biological systems can be unpredictable…patients die despite our best efforts to save them. Case in point, several of the comments on this post that are suspicious of death by Convenia had pets with serious underlying medical issues. I wonder, how many of the hundreds you speak of may have received Convenia in an attempt to treat infections that were the secondary result of tissue and organ compromise from serious systemic disease. How many may have had their fate already sealed well before Convenia was ever administered?

      I am sorry about your dog, and after the tragic loss of life, it is one’s right and prerogative to seek answers as to what may have happened. A post mortem examination by a third party pathologist – that Zoetis would likely have paid for if you suspected Convenia was to blame – would have been the best way to answer these questions.

      At any rate, 5 years of FDA trials, followed by 8 years of clinical experience with 8 plus years of retroactive data as proof that Convenia has an extremely high safety profile and high degree of efficacy is a large body of evidence.

      Best regards,

      Dr. Roger

      • Laurie bartkoskiartkoski says:

        My cat died three hours ago and is Enrique to her necropsy. I am so angry about this. People have been complaining since 2011 and yet NOTHING! There needs to be an outcry and this drug needs to be BANNED FROM USE

  4. DON AGNOR says:

    I have a cat, that has diabetes and has had a vicious uri for about a year. I had run the gamut with oral antibiotics and none of them worked. I stumbled upon an article about Convenia, being useful in fighting uri’s. I went back to my vet and got the Convenia injection and within a week it cleared up his uri. I consider this to be an effective antibiotic, as far as my cat’s concerned.

    • P. Stuyvesant says:


    • Dr. Roger says:

      Don, thank you for sharing, this is perfect example of “off label use” of Convenia. It is only FDA labeled for skin infections because that was the primary FDA approval based on trials and its main target for infections as a third generation cephalosporin. FDA trials are expensive, so once approved on the basis of safety and effectiveness in skin infections, the manufacturer did not incur the expense of additional approval because veterinarians understand the pharmacology of cephalosporins, the spectrum of coverage, and are perfectly capable of deciding for themselves when extra label use is appropriate…cephalosporins also tend to be very effective against upper respiratory infections and urinary tract infections warranting off label use, the likes of which served your cat well.

      While extra label use serves a fodder for the outraged anti-Convenia crowd, they really do not understand what extra label use means.

      Best regards,

      Dr. Roger

  5. h nolan says:

    I’d have a great deal more respect for your opinion on this matter if your responses to the concerns on this page weren’t so very disrespectful.

    The people leaving their comments are doing so out of concern for their beloved animals, whether their opinions are correct or not. You are the professional, and yet your flippant attitude leaves me wondering how much you observe in the animals you’ve treated when you can’t even treat the concerns of pet owners with some measure of respect. Sasquatch? Really?
    Calling people pathetic? Really?

    If you are going to offer up the excuse that you are frustrated by the lack of understanding in those with whom you are corresponding, what business do you have with an online presence that is for the express purpose of communicating with others?

    Next time, take a deep breath and ask yourself how likely you are to listen to someone who talks down to you the way you are talking down to people here.

  6. Becca says:

    I see you’re very comfortable with the safety of this product. But I came across your bog when researching the affect of Covenia on kidneys. Here’s our story: what’s your thoughts? Diabetic (controlled with diet and insulin) older (14yo) cat in otherwise good health. Has UTI (blood in urine, pos. culture for E. Coli). Bloodwork showed normal kidney values. Given Convenia injection. Three to four days later stops eating, drinking and lethargic. Return to vet hospital for more testing. Urine clean of all bacteria but now in acute renal failure. Is there no chance that convenia (metabolized in the kidneys) triggered the renal failure? Getting daily fluid which are helping appetite and lethargy. Chance for recovery? Thanks in advance for a considered (non-defensive) response!

    • Jacqueline says:

      Hello. Did you ever receive a response from your question? My 6 year old cat received the convenia injection for a claw that grew into his paw pad and had to be cut out. 2 months later he passed away to kidney failure. His blood levels were taken in Feb 2015 with no kidney issues. I am heartbroken and searching for answers.

      • Dr. Roger says:


        I am sorry for your loss. Please note as I stated to Becca that zero metabolism of Convenia occurs in the body. It is excreted unchanged via the urine. I would encourage you to retroactively go back to the blood values taken in Feb, 2015. The reference parameter for consideration of degenerative kidney disease has changed per the American Feline Renal Society, yet many veterinarians and even the reference labs have not yet caught up. We consider the kidney value creatinine elevated at 1.6, whereas, many vets and reference labs still go by the dated level of 2.1, leaving many feline owners with the false idea that their cat has healthy kidneys with elevations north of 1.6.

        Also, I see this was posted in late March, 2016, making that bloodwork more than 1 year old. i year of a feline’s life is equivalent to 3-4 years of a human life, leaving ample time for good health status reflected in normal blood work (if it truly was normal by modern kidney medical standards) to to have changed. Kidney failure has been the number one killer of cats as long as I can remember well before the launch of Convenia in 2008.

        Again, sorry for your loss.

        Best regards,

        Dr. Roger

    • Dr. Roger says:

      There is no “metabolism” that occurs in the kidneys kidneys or anywhere else for that matter. Convenia is eliminated via the urine unchanged, which is why it is particularly effective for urinary tract infections.

      Diabetes, on the other hand, commonly causes glomerulonephritis, inflammation of the microscopic filtration apparatus of the kidneys. Diabetes also enables ascending bladder infections up the ureters into the kidneys leading to kidney infection, leading to pyelonephritis and acute renal failure. As you stated, urine follow up showed clearing of the infection, but between the diabetic nephropathy and the pyelonephritis, the damage was done Convenia notwithstanding. The infection and diabetic state in a geriatric patient are the far more plausible explanations for acute renal failure from pharmacologcal and pathophysiological standpoints.

      Sorry, I just caught up with all of these threads, so I know this is dated. Acute renal failure is a very guarded prognosis when taken alone, ever more guarded when diabetes is involved. I really hope your girl pulled through.

      All the best,

      Dr. Roger

  7. Lisa says:

    I think the problem with Convenia is that should your cat be one of the unlucky ones that has a reaction there is no way to reverse it since it is so long acting.

  8. Martha Waltien says:

    I cannot be sure you even knew about the reactions to cats you gave Covenia to. You weren’t with them in their homes. So, how can you attest that you didn’t have lethargy? Our Toby had a Covenia shot after a full mouth extraction (dental surgeon) and I was not even asked – he could easily have gotten clindamycin in his food which I have done successfully for years. Well, Toby was very much affected by that shot. He was acting very weird, wrapping his body around a table lamp, hiding in closests, etc. for 3 weeks. (We had 3 other FME with no Covenia and they all had the Fentanyl patch – zero weird behavior or lethargy.) Then, two of my stomatitis caretakers told me that each of them had a cat die on the table from the Covenia shot. I believe Dr. Pierson.

    • Dr. Roger says:

      Clindamycin is FAR more potentially toxic comparatively to Convenia, which is why we try to avoid it as much as possible. It covers dental pathogens well, but it is very hard on the liver which where primary metabolism of the drug occurs.

      Convenia, on the other hand, covers dental pathogens well, does not require oral medication in a painful mouth, and is eliminated unchanged via the urine. If your cat had a post-op Fentanyl patch, that is the more likely explanation for the weird behavior. This is why I have not used Fentayl in cats for years…buprinorphine is an excellent opioid pain reliever in cats and well well tolerated. Post anesthetic agitation is also common for 24-72 hours.

      So, how can I attest to my lack of reactions to Convenia in my vast experience with it? Clients of every sick patient that has received treatment (Convenia or otherwise) or had surgery receives a follow up medical progress call from a member of my medical team the day after. My clients are also encouraged to call if they have any questions or concerns at any time and my doctors and I always take calls or call back to address concerns.

      If Convenia caused illness or death of a patient, it would be highly likely that I would know given this system of engagement and encouragement of owners to communicate any problems ASAP.

      Best regards,

      Dr. Roger

  9. Dr. Roger says:

    My apologies, in a few posts, I wrote that Convenia is excreted unchanged via the urine and does not undergo any metabolism in the body. Slight correction: is true that it does not undergo any metabolism in the body and is excreted unchanged, but this excretion occurs via the bile NOT the urine. That means it exits via the stool unchanged, but the truth remains the same…it is not metabolized by any organ systems in dogs and cats.

  10. Dr. Roger says:


    This is a very large blog, so I just was made aware of all of the comments that resulted from this post. I took three hours of my morning to address any many as possible that I felt deserved a response.

    I would encourage the discussion to continue, but keep it respectful. Profanity and insults are not necessary when the main reason we are all here is to protect our beloved innocents that do not have a voice and obtain the truth. The truth is not always clear, which is why discussion is very important.

    Beyond the comments I engaged in today, please do not take it as me being dismissive of future comments if I do not respond. To answer all of them would require me to spend several hours a day answering them. I have too many patients to see and more topics to write about to engage constantly, but I think my article and responses I engaged in today should make my position clear enough.

    Thanks to all who – respectfully – contributed their comments and offered their opinions.

    Best wishes to all,

    Dr. Roger

    • Richard Jaouen says:

      I would like to add my comments to Dr. Welton’s assertion that Convenia doesn’t cause serious and sudden death complications. Many people in this thread have complained that Dr. Welton is condescending and arrogant and dismissing their evidence. Given some of the comments I’ve read, I think he has acted admirably.
      In human medicine we are currently in an era of “evidence based medicine”. That essentially means that best practice is based on the best evidence and that evidence can be rated as to its quality. In mast scales the best evidence (level 1) is based on very thorough studies and the weakest evidence (level 5) is based on expert opinion. The only thing weaker than level 5 evidence is anecdotal evidence. It’s easy to see that both sides in this argument are based on very low quality evidence.
      Anecdotal evidence is base on chance and almost always contains personal bias. Many of the cases given in this thread are understandably biased and lack important information. Take the case of the animal with an abscess that was otherwise healthy and then died hours after injection. The Surgical Infection Society has defined the treatment of abscess as drainage and cleaning and allowing the wound to drain. Antibiotic use is optional and up to treating practitioner. We have no idea if this abscess was opened and really lack enough information to make a rational judgment.
      The only way to find out the facts about Convenia is to establish a national database. Anyone can do this but I would suggest doing through an academic program. They have resources like students, residents and statisticians that can help you. They also have contacts with working Veterinarians that can participate. I would avoid manufacturers involvement. Having as many veterinarians as possible giving pet owners a questionnaire to fill out 1 week after Convenia injection and mailing to database would be first step. Adverse reactions could be crossed checked with vet records and trends could be established. Having all Convenia injections recorded would give an idea of frequency even though owners with animals with no reaction are less likely to comply. With a good vet base of 30-40 physicians it wouldn’t take long to accumulate a couple thousand cases. Trends could be analyzed and the magnitude of the problem as well as its nature could be determined. Then you would have a basis for action or inaction depending on findings.
      This is the logical way to approach this question. The current method obviously isn’t convincing anyone.

  11. Lisa kitchens says:

    I’m a vet technician that works as executive director for a nonprofit animal rescue. I was lucky enough to participate in a Maddies Shelter Medicine Parvo Outpatient Program in Philadelphia last summer. Convenia is used in this Parvo outpatient protocol which has saved thousands of animals. Think risk/benefit. The benefit of using this drug far outweighs any possible risk. Calling for Convenia to be removed from the market would be devistating to these parvo puppies who now get a real chance at life.
    Thank you for your defense of this amazing drug.

  12. Jackie Vanka says:

    My cat died after being given Convenia injection. From what I have read the inconvenience of giving your cat a daily anitibiotic or giving them a drug that could possibly kill it is a no brainer. I would have gladly given my cat the medication everyday. It’s really not worth the risk. It doesn’t leave the system for 14 days, if there is an allergy, it’s a death sentence.

  13. Nicolle Wilfenger says:

    My dog had sutures and 10 days later, wound is infected in spite of getting a covenia shot day of surgery.

  14. Lauri Robertson says:

    My 9 year old cat, Bradley, had Convenia for a facial abscess following a fight. He died several weeks later of fulminant histiocytic sarcoma (autopsied at Tufts). It’s exceedingly difficult to think the Convenia wasn’t the cause…

  15. Mike says:

    I just took my 9 year old cat to the vet for a cold. The vet said he’s going to give her an antibiotic shot. I thought ok that’s good now I don’t have to fight with her to take a pill…… big mistake!!! A few days later she stopped eating, she would go upto her bowl like she wanted to eat and wouldn’t. Same with her water. 5 days later she was nearly lifeless. I called the vet and they didn’t seem to care and told me they can’t get her in to see her for another 4 days.
    So I ran across the street to Walgreens and bought pedialyte, baby food and a syringe, came home and started giving her water with the syringe then baby food to get her hydrated and nutrition. As two days passed and she look like she was on deaths door. I called my vet and demanded they see her. Upon going in they took blood test from her and hydrated her. As I also keep giving her pedialyte and getting her to eat every chance I can. I know my cat and her health and habits and I know ((for sure)) that antibiotic had a role with her being deathly ill and if it wasn’t for my quick response I would have lost her… she’s not out of the woods yet tho she’s still suffering from it but I’m keeping a close eye on her. Had I not noticed or paid attention to her she would have died and I am certain it was this antibiotic.

  16. Kim says:

    Well what about all these poor animals that convenia has killed… think about those poor babies!!

  17. Olga says:

    Here’s what I found on Zoetis website about Convenia in the “Prescribing Information” link: “FOREIGN MARKET EXPERIENCE: The following adverse events were reported voluntarily
    during post-approval use of the product in dogs and cats in foreign markets: death, tremors/
    ataxia, seizures, anaphylaxis, acute pulmonary edema, facial edema, injection site reactions
    (alopecia, scabs, necrosis, and erythema), hemolytic anemia, salivation, pruritus, lethargy,vomiting, diarrhea, and inappetance.” So these may not be commonly observed side-effects but they are included. I have read Dr. Pierson’s article and then did some additional reading to make up my mind. I came to the conclusion that I don’t like the idea of this drug being in the body for almost 2 months, even though it says it only exerts its effect for 2 weeks. I ask my vet not to give this drug to any of my cats, instead, we go with whatever he deems appropriate and I have to medicate them on a daily basis. I’ve come to the conclusion that there is a place for Convenia and it’s for animals who are very hard to medicate, or for people (owners) who either can’t medicate their pets, don’t have time, can’t do it consistently, or simply don’t care. In our household, I can medicate most of our cats but one, who is feral, and I know that if she ever needs an antibiotic it will be Convenia and I’m OK with that. If an outdoor cat I don’t get to see regularly gets sick and needs an antibiotic, it will be Convenia. Not out of convenience, but out of necessity in both cases. I’ve read a few comments here and see some opinions regarding vets. I’m a vet tech student and I’ve been shadowing vets and learning a lot. One of the things I’ve learned is that just because a person went to a vet school and has a degree, doesn’t make him/her a good vet one can trust. I’ve seen how clients trust a vet, how they listen to every word and how uneducated and ignorant they are for the most part when it comes to their pets’ health, which is normal I guess since one can’t really know everything. It wouldn’t be a problem if every vet was really up-to-date on the latest advancements in the veterinary medicine, versed in all species, honest and really cared about his/her patients. It’s not happening because they are people too and just as flawed as everyone else. I worked with a vet who used to be a large animal vet his whole life and then after retiring was hired by a non-profit animal shelter to work with dogs and cats. While he can perform spay&neuter surgeries with his eyes closed, he has very little knowledge of felines, and yet he treats them and people/clients/shelter management trust him with them. I’ve seen a few things done wrong, nothing illegal, but definitely wrong and the doctor wasn’t open to making any changes. By the way, I didn’t go to Dr. Google to learn what I know about felines, but I listened to multiple veterinary webinars provided by AAFP, and also through International Cat Care organization that provides webinars for vet nurses every month. I guess my whole point here is that just the fact alone that a person has a degree in veterinary medicine doesn’t make him/her more trustworthy than certain information from the right source on the Internet; it doesn’t mean that people should automatically trust their veterinarians. Instead, if you really care and have time, educate yourselves, but do so through the right sources. Once you do, talk to your vet and discuss your concerns with him, ask to explain what you don’t understand. A good vet will do it, ours sure does. I definitely wouldn’t trust “Dr. Google” as I’ve seen what it does to animals whose owners want to avoid taking their pet to the vet.

    • Dr. Roger says:

      This is reasonable and intelligent rebuttle. Ai am glad that you stated that these are POTENTIAL side effects and have to be listed regardless of incidence. Still, you only will resort to Convenia if you have to and I respect that. Incidentally, here are the side effects of Advil in people straight from the company’s website:

      Vomiting, diarrhea, heartburn, stomach and intestinal ulcers/bleeding, kidney failure, liver failure, seizures, priapism (an erection that will not go away), headache, high blood pressure, dizziness, stroke, sudden acute death.

      Yet we never here about how dangerous Advil is.

      Thanks for your non-sensational and intelligent comments. This contributes to a good discussion.

      Dr. Roger

  18. Lauri Robertson says:

    I am a physician, not a veterinarian. My previously healthy 9 year old cat died of fulminant histiocytic sarcoma @ 6 weeks after receiving Convenia for an abscess (secondary to a cat fight). It’s very hard not to speculate that there was a causal association…

  19. michelle mcdermitt says:

    Whoever wrote this article is an utter liar go to the web page about convenia on facebook and you will see not one not two but hundreds of people who have lost a perfectly healthy pet to convenia, Yes it may work for some animals. but don’t lie and say you have never seen any pet react to it. My cat went to the vet with a limp was given convenia even though his bloodworks all came back perfectly normally, he collapsed 20 mins after and literally could not eat or move or go to the toilet, yet half an hour before it he was doing all 3, such blatant lies, you should be ashamed

    • michelle mcdermitt says:

      forgot to add he died exactly 14 days after it being administered, a 14 days shot that killed him when the 14 days were up its a disgusting drug it should be banned, my cat was perfectly healthy he had a sore leg nothing else and he died in for absolutely nothing

  20. Fran M. Glat says:

    My dog had 100% flawless blood work the evening that she received Covenia. 8 days late she woke up very thirsty and drank 12 bowls of water in one day. I took her back to the Vet and her BUN, Creatine, and all of her liver panels were elevated. The morning she got Covenia her BUN was 20 and it shot up to 33 in 10 days, and then went to 55. This is NOT a coincidence. I found the FB Covenia adverse reaction in felines and dogs and I was shocked. I called Zooetis and reported it and they told me that the drug does NOT 100% come out of cats and dogs for up to 65 days.Most Vets have no idea and think it’s out of their body in only 14 days. If your pet has an adverse reaction you are stuck with Covenia in their body for 65 days. I am happy to report that my dogs kidney panel and liver panel has returned to normal after 9 weeks of being administered Covenia. My Vet did agree that my dog had an adverse reaction to it. DO NOT GIVE THIS DRUG TO YOUR PET! There are other antibiotics that you can use that do not stay in their body for up to 65 days.

  21. WindowCat says:

    We took our cat to the vet because we thought she had a bad tooth, she was otherwise fine but her breath smelled very bad. They agreed at the appointment she had to get a few teeth removed and we set the appointment. They gave her Convenia to stop whatever infection may be present in her mouth and took pre-surgical blood work. She started falling when she walked and took a sudden sever downward spiral that night. They called back the next day and said her BUN levels were very high and they thought she was in kidney failure. The blood work was before the Convenia injection but she was eating, drinking, walking normally before she was given the injection. I think it sped up her kidney failure exponentially! She is beyond treatment now and she is suffering. She should never have been given this drug. Once administered there is no way to get it out of her body. I believe Convenia did took away the time we had left with her and any hope of managing her kidney disease. Since the injection she can barely walk and is no longer eating, before the injection she was running and jumping and eating and drinking. It’s only been 2 days since the shot and now she is on death’s door. I will never let another vet give this to one of my animals. They didn’t even offer us daily antibiotics, they just gave her this shot when they took her blood work. I don’t understand why they need blood work for anesthesia before surgery but not before they give them this powerful drug that will be in their systems for potential months? It seems very very wrong.I think blood work should always be preformed BEFORE this drug is administered.

  22. Pam says:

    My healthy 8 year old cat had a small abrasion on his stomach.My vet asked me how he was at taking pills. I said “Great” because he was. For some reason he, without asking me, then gave him a shot. He said “Now you don’t worry about giving him pills. This antibiotic will stay in his system for 14 days.” I said “I wasn’t worried, he is good with pills, but ok”. Huge mistake. Within 4 hours he started having mini seizures. He twitched and did not want to be touched. I called the vet, but there is nothing they can do. It is in his system for 14 days. So, I saw no reason to take him back. After desperately researching, I came across someone talking about probiotics helping. They had tripled the amount and saw some favorable results. It made sense to me because antibiotics destroys both good and bad bacteria. I started pilling him with probiotics.He hid under the bed for 3 weeks, only coming out to use litter and drink water. I hand fed him, the only way he would eat, small meals 8 times a day. He still had mini seizures for almost a month. It really does not disappear for 40 days completely from the system.I credit the probiotics for getting him through this. 5 years later he is a healthy cat of 19 lbs. Yes he is a big Maine.I will never use Convenia again, it wasn’t a fluke and was not worth putting something in his system, that cannot be stopped when reactions happen.There was no convenience for me, just fear and heartache. I, also, Now know, for myself and my pets, to take probiotics when taking antibiotics.It should be standard with a drug like this. I hope my story helps someone in need. It is so scary when you are in the middle of this.

  23. Charles Kimbrough says:

    I’ve done a lot of research on Convenia, after a Vet gave to my Cat without my permission. I wanted to beat that Vets ass. But I didn’t feel like going to Jail. Fortunately I’m not stupid & my Cat survived. However my Cat has had a Respiratory problems ever since.
    And Dr. Roger Welton is the one spreading Misinformation. Because 90% of the Cats die from Convenia. The true number 1 side effect. Is DEATH!

  24. JN says:

    The veterinarian who administered the Convenia injection to my cat, is the one who informed me that the Convenia injection resulted in the side effects and eventual death, of my cat. My cat received the Convenia injection to treat a skin infection on his nose. THE NEXT DAY, he developed neurological symptoms.. he was staggering, and could barely walk, and was falling over when he tried. He stopped eating and drinking. Additional blood work was completed, confirming that he had developed hemolytic anemia. More and more tests were done, over the next week, while he continued to worsen and suffer greatly. He was not getting up, not eating nor drinking. Finally, he had to be taken to the specialty hospital. They placed him on oxygen immediately, as he was struggling to breathe. They advised me that they could do a blood transfusion, however, his anemia had gotten much, much worse and, based on his ultrasounds, leaking internal fluids were building up around his organs. The veterinarians supported my decision to put him to sleep, one week after he received the Convenia injection. I submitted a report to both Zoetis, the manufacturer of Convenia, and also the FDA. Multiple veterinarians have prescribed Convenia for my cats over the years, and never have I been given any warning of the possible side effects. Zoetis needs to be more forthcoming about the facts/dangers regarding this drug. The medical community needs to educate itself, instead of being complacent, and in some cases, smug and condescending.

  25. Jeanette Clinton says:

    About a month ago, I took my otherwise healthy and happy 18 month old, 7 pound cat to the vet with an abscessed tooth, at which time she was given a shot of Convenia. Since that time, she has gone straight downhill, lethargic, and losing nearly 2 pounds in a month! When she began peeing on my bed, we went to the vet again. Bloodwork revealed she now has kidney disease, according to this vet, yet she is just a baby! I have numerous other cats and over time have had several different cats injected with Convenia for various reasons, without any negative outcomes. Yet, this time, I have to say I believe in my heart the Convenia caused this issue. Yes, under the right circumstances, I would use it again, as many of my kitties are very difficult to pill, especially when it must be done on a daily basis. But I agree that it should only be used after informed consent is received. In this case, my Macy was given the shot without question or consent. To be honest, I would have agreed to it, if liquid medication could not be used successfully as an alternative, but only then. I feel like this baby’s life has been cut short unnecessarily, and my heart aches for that.

  26. nancy says:

    laurie,iam so sorry about your baby,i am going through same my elderly cat with compromised immune system & renal was given by my vet of 44 years ,he too says its ok & but she is in e.r & will have to be put to sleep soon .the day before this little 4 lb cat was running around jumping on the sofa,playing with my other cats & trying to steal my food.he also gave my other cat with cancer & f.i.p the same 2 weeks ago.i dont know how these monsters can take a chance.would they give it to their child or grandkids,you know they wouldnt.

  27. Dean DeDominicis says:

    My beautiful baby precious was given a shot of convenia yesterday 2/3/22 for an upper respiratory infection w/ no pneumonia, just congestion in the head area, & she died at 2:30 this morning.

    I’m so upset right now so whoever says this drug has no sode effects which ate lethal are full of sh*t.

    My baby is now gone because of this shot.

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