Ask a Vet: What Are the Risks of Steroid Injection in Cats?


A few weeks ago I saw a cat who was having trouble breathing.

Breathing difficulties are the most serious and urgent condition that any vet ever treats. It’s all over after a few minutes without air. It was a busy night, but the cat jumped the line and immediately became my top priority. For the record, if you are at an emergency hospital with your pet, you want to be the one kept waiting. You never want to be the one to jump the line.

In cats (as in all species), stress increases the need for oxygen. Cats who have difficulty breathing are at risk for a catastrophic cycle. They can’t breathe well, so they become stressed. The stress increases their need for oxygen, which in turn can’t be met because of the underlying respiratory problem. That leads to more stress, and more need for oxygen, and so on.

The cat in question was panicked when she got to the office. She did not want to be handled. She was gasping for air. She was on the brink. Any handling of her could push her over the edge. She received a tranquilizing injection and she was placed in an oxygen therapy unit. As her stress level improved her breathing got better, but it was still far from normal.

Photo of Dr. Eric Barchas by Liz Acosta
Photo of Dr. Eric Barchas by Liz Acosta

Some clients whose dog had an ear infection very graciously vacated an exam room so that I could speak with the cat’s owners. An assessment of medical and lifestyle histories often yields insight into cats with breathing difficulties. Outdoor cats might suffer trauma or infections in the chest that can lead to breathing difficulties. Cats with histories of heart murmurs might have heart disease that can lead to congestive heart failure and respiratory distress. Cats who have a history of coughing might have feline asthma, which can progress to severe respiratory distress.

The cat in question lived exclusively indoors. She had been completely healthy, with no concerns except for an occasional skin rash. In fact, she had been to the vet a couple of days earlier because of a rash. She was found to be otherwise healthy at that time.

She went to the vet and she started having trouble breathing a short time later. I began to develop an idea of what was wrong.

I asked the owners whether the cat had received any medications or injections at her previous veterinary visit. I was advised that she had received an antibiotic injection and had been sent home with a steroid cream.

Respiratory system of the cat by Shutterstock

Antibiotics almost never lead to breathing problems. Steroids, on the other hand, can. The steroids in creams, however, usually aren’t well enough absorbed to cause as severe of a crisis as this cat was suffering. I had a hunch. I asked whether, by any chance, the owners had a receipt from the visit two days earlier.

Indeed they did. Like many organized folks, they kept a file of veterinary information for their pet. Cleverly, they had brought the file with them. The receipt listed three items: Exam, Depo-Medrol injection, and hydrocortisone cream.

Deep-Medrol is not an antibiotic. It is a long lasting steroid. And with this information I knew exactly what had happened.

Deep-Medrol is not a muscle building steroid. It is related to cortisone, and it fights inflammation in the body. Most skin rashes involve a significant component of inflammation. Cats generally react well to Depo-Medrol unless it is given repeatedly (which might trigger diabetes). However, one group of cats does not tolerate the medication well at all: cats with weak hearts.

A cat at the vet by Shutterstock

As I discussed in a recent column, cats with heart problems often have no detectable symptoms or physical-exam abnormalities until a crisis occurs. Depo-Medrol has the potential to precipitate such a crisis. It alters the way that the body stores, uses, and distributes water, and it can trigger heart failure in a cat with a weak heart. Heart failure causes fluid to build up in the lungs. Fluid in the lungs causes respiratory distress.

I asked the technicians to administer a diuretic to the cat. Diuretics cause the body to excrete water in the form of urine. This reduces the heart’s workload and helps fluid clear from the lungs. The cat’s breathing improved to the point that it was deemed safe to take X-rays. The X-rays showed abnormal patches of white throughout the lungs. It was a pattern compatible with heart failure.

Over the next 24 hours the cat received a continuous intravenous infusion of diuretics. Her breathing steadily improved. After 12 hours she no longer required supplemental oxygen. After a day, she was able to go home with oral diuretics.

The incident served as a reminder to me. The steroid injection had not caused the cat’s heart failure. She had a weak heart to begin, and the injection merely pushed her over the edge. But steroids are risky as well as beneficial. They are simultaneously the best and worst medicines ever invented. They should be used judiciously, and only with the full understanding and consent of the cat’s owner.

19 thoughts on “Ask a Vet: What Are the Risks of Steroid Injection in Cats?”

  1. I’m 9o% certain it the depredil injection killed my 17 years old otherwise healthy (other than over-grooming) cat. Within 12 hours of the injection, it was over and his death was horrendous, he needed my help and I was useless. Struggling to breathe he came to me, as I tried various ridiculous unhelpful things (like offering water) he let out a few yowls and died in my arms. I’m devastated. His death was terrifying for him, and painful. I’m angry and sad, I really had high regard for our Vet, that’s now sadly in question.

    1. My deepest condolences. I have thought about steroidal shot to help my 19 year old with pretty severe hip issues..I wil not proceed thanks to your heart wrenching story.

  2. My cat has asthma and received a depo injection between her shoulder blades. She developed a lump at the injection site. It’s been a month later and the lump is still there. It hasn’t gotten any bigger and is freely moveable. Does this happen often?

    1. I just found this same thing in my 2 year old cat. He had a steroid injection about one month ago and I just noticed a lump between his shoulder blades. I have a vet appt for Thursday, but can you tell me what you found out with your cat?

      1. My cat developed a similar lump a few days after receiving the depo injection. The lump was surgically removed and biopsied. The vet said the biopsy indicated the lump was a pooling of the injected medication. They can’t tell us why it happened. No more steroid injections for her ever.

      2. My cat did that with the first 2 shots. We discovered that cats should be given the shot in MUSCLE. She is now on it on “as needed” basis… every 6 to 8 weeks till the wheezing starts up. I make sure to remind the vet each and every time …. “IN the MUSCLE”.

  3. My cat has allergies and get prescribed prednisone 5mg to be given orally once daily for week, I had problem giving the pill to him,took cat back to get to see about shot instead,and she was very cautious and said because he had heart murmur,she would not give shot,thank god,after what I’m reading here,I’m so glad she refused,so many vets before her,easily gave him shot, I will stick to the oral liquid prednisone and have a healthy cat!!

  4. 7 days post a depo shot (didn’t know it would be given–she went in for ear mites), my 9 yr old cat is in total shut down: extreme pancreatitis, sepsis, fluid build up, kidney failure.
    She seemed fine and then, a minute later, she went downhill fast. She is in an O2 chamber, BP pump, etc. They are still giving steroids along with anti-biotics. She may not make it through the night.

    I am so heartsick.

  5. I to just lost my indoor 13yo FIV+ DSH cat to steroid-induced CHF+Cardiomyopathy. He had received a clean bill of health other than his long term stomatitis (several ulcers in the mouth). In which we had been treating for over 2 years with Prednisolone. So like normal, restarted his dose high 2.5mg every 12 hours for 3 days and taper to about 1.25 that for about 2 weeks. Then when things going well I’d switch to 36 hours of 1.66mg (3 doses, 12 hours apart) then 36 hours of no dosing whatsoever. Then restart the “1.66mg of at 3 doses (12 hours apart) ” and back to 36hours off. This worked well for about 2 years. The idea was he had those 36 hours to be free to fight infections.

    I have no doubt he had an undiagnosed weak heart (Cardiomyopathic) before this but my increasing his steroids this last time sent him over into CHF.

  6. I feel they should take depomedrol off the market. My cat has received 5 depomedrol shots in the last 4 months, and now she has heart disease. She was given depomedrol because she is a chronic vomiter. She just spent the last 2 days in the hospital due to congestive heart failure. Cats have lived with me for the last 27 years, and this is the worst experience I have ever had with my cats. I thought my cat was going to die. Now she has to take 3 pills a day for the rest of her life. She is 10 years old and the Dr has forecasted that she will only live a few months to a year. Do not allow your vet to give your cat depomedrol.

    1. My cat died last night after getting the depo medrol shot w her vaccines. I found her dead within a couple of hours after returning from vet.
      Never mix shots, she had the Felv shot, rabies shot and 4 in 1 shot.

      1. That is just terrible! I am so sorry that happened to your cat. I had a cat too that got too many shots at one time. He ended up staggering all over. It scared me. He did survive. You would think the vet would know that is very risky.

  7. I have an approximately 14-year-old feral cat whom I have cared for for the past eight years. He is an indoor cat. I recently noticed that he was having difficulty eating, so I drove him several miles away to undergo a dental procedure. Instead of improving upon his return, he declined. He stopped eating and drinking. After a week, he was in such a feeble state that I was able to give him 65 mL of ringers subcu, and took him back to the vet.

    I discovered that he had been given a Depo-Medrol shot when he had his teeth done. I was unaware that this was the plan for him. The reason he was unwilling to eat or drink is because he had developed stomatitis and had several ulcers in his mouth. He was given another Depo-Medrol shot at his second visit. I consented to this injection because I was so concerned about his unwillingness to eat or drink. I was hoping that, by suppressing the symptoms, his appetite would improve. It was also my understanding that the steroid would increase his appetite. I now realize that this was a terrible mistake.

    In order to counteract the immunosuppressive effects of the Depo-Medrol, I am currently giving him a homeopathic remedy to specifically address the stomatitis. He is on a very low potency, 6C, and is gradually beginning to eat again. I will need to continue this treatment until he is completely back to normal. I am also getting him a teaspoon of organic decaf green tea with his food in order to soothe the raging ulcers.

    Had I known that the plan was to give him an immune suppressing shot in the form of Depo-Medrol at his initial visit, I would have never consented to it. My cat continues to be dehydrated, and, because he is feral, it is important that he trust me again, so I am unable to give him any more fluids.

    I am praying that the homeopathic remedy works. I am giving it to him in organic cream twice every day, and thank God, he licks it up on his own.

    In the future, any of my cats who undergo a dental procedure will absolutely not be receiving this “allergy shot”. In my opinion, all the Depo-Medrol did was destroy my cat’s normally very healthy appetite, and prolong his recovery from the dental procedure.

    I am praying that my kitty will survive this ordeal. In my opinion, it was totally avoidable.

  8. I am going through a similar situation with my cat as well and he is allergic to vaccines, I had not known any better and didn’t do my reaserch before allowing vaccines. But I found out that he is very sensitive with injections. He had a upper respiratory infection and was given depo medrol and the next day I had to rush him to Thebes hospital because he couldn’t breath. Had fluid in his chest cavity and was admitted for a 2 night stay. Given lasix and a “heart pill” because they told me he has conchestive heart failure. He was a healthy 7 year old 16 pound cat that never had any problems before. After reading this story it makes sense if he has a weak heart to begin with that went undetected. I also found the same ugly scabs and lump at the injection site this time as I did in the past and he actually had to have some tissue removed and was left with a hole because the injection killed the surrounded tissues. This story gives me some information and reason to look further into his case and hopefully I can save my cat from the nasty injection again.

    1. Don’t do it – I made this horrible mistake and it triggered heart failure. Although she was saved in the ER in the immediate term the damage to her heart was sever and I lost her two months later due to the permanent damage caused to her heart.
      I STRONGLY recommend avoiding steroids entirely in cats with heart conditions, but my understaning is that oral steroids can be better managed if heart failure is triggered.
      Get a second recommendation or better yet call the Vet program and a top Vet university for a proper education of the risks and treatment options for your cats situation. Washington State University is excellent for providing additional information.

  9. My question is if the cats exam was normal…no murmur or crackles,fluid etc by the vet ho is the owner supposed to know or give proper consent for the injection? They are looking for the best treatment and relief therefore relying on the vets exam and recommendation.Second if the vet did the exam and as confident in his treatment of choice to be the injection howis he or she supposed to predict such a reaction ekg or ultrasound for every depo injection? Was this a geriatric cat?

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