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.


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  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.