Last updated Apr 4, 2026
Kirsten McCarthy / Cats.com
Budesonide is a glucocorticoid steroid that is often used as an alternative steroid option for treating chronic inflammatory digestive conditions in cats.
In this article you’ll learn what budesonide is, how it works, potential side effects to watch for, and some frequently asked questions.
Budesonide For Cats Overview
About Budesonide for Cats
Budesonide is a glucocorticoid steroid, also called a corticosteroid. Steroids are generally divided into glucocorticoids, which have effects on stress and immune response in the body, and mineralocorticoids, which primarily are associated with fluid and electrolyte balance.
In veterinary medicine, budesonide may be used to treat cats with chronic inflammatory enteropathies of the gastrointestinal tract, also known as inflammatory bowel disease, especially if there is concern about using a steroid like prednisolone, which has more systemic activity in the body.
While most cats tolerate prednisolone very well, its full activity systemically through the body may lead to concerns for cats at risk for diabetes (or who are currently under treatment for the disease), and cats at risk for heart disease or who have been diagnosed with a heart condition.
What Does Budesonide Do for Cats?
Budesonide has been used for a long time in cats with inflammatory bowel conditions, and appears to be tolerated very well. Kirsten McCarthy / Cats.com
The reason budesonide is a good alternative to prednisolone for cats when there is a concern about using a more systemically-acting steroid like prednisolone, is because of the way that budesonide is absorbed by the body and how it acts.
Budesonide reaches very high topical concentrations in the lining of intestinal tract tissue, exerting great anti-inflammatory and immune-suppressing activity localized to the gut.
But it is otherwise largely eliminated from the body by a process called a first-pass metabolism effect in the liver. This keeps it from reaching high concentrations throughout the rest of the body.
Although budesonide has more of a limited, localized effect, it should not be thought of as a “weak” steroid. In fact, budesonide is actually a very potent steroid.
In terms of efficacy, many veterinarians consider budesonide and prednisolone to have the same level of effectiveness for treating inflammatory bowel conditions in cats. Budesonide should simply be thought of as a good alternative if there are concerns for systemic steroid use, especially due to diabetes or cardiac conditions.
Budesonide tends to be more expensive than prednisolone and has to be specially ordered through a compounding pharmacy, making prednisolone still a good first-line medication choice in many cases if it is likely to be well-tolerated.
Separate from digestive conditions, budesonide has been shown in studies to improve signs of asthma and chronic bronchitis in cats when an inhaled form is used. However, commercially available budesonide products for inhalation are not compatible with the inhalation chambers widely used for asthmatic cats, making budesonide a poor practical choice for this purpose.
While it is always used in an off-label manner for cats and there is a little official study of its use in cats, budesonide has been used for a long time in cats with inflammatory bowel conditions, and appears to be tolerated very well.
In fact, most cats appear to generally tolerate long-term use of steroids (which is typically always required for inflammatory bowel conditions) pretty well compared to dogs and humans.
As mentioned, the whole point of using budesonide is to limit systemic side effects. Although less commonly seen in cats typically, side effects of using a glucocorticoid can generally include signs like weight gain, hair loss, increased drinking and urination, increased breathing rate, and increased appetite.
But while having few systemic effects, budesonide does still have potent activity locally in the digestive tract. And in this regard, it can have side effects seen with prednisolone as well, like stomach and intestinal erosion and ulceration.
These adverse effects can appear as black tarry stools, bloody vomit that has the appearance of coffee grounds, lethargy, and poor appetite. Most cats with inflammatory bowel don’t exhibit vomiting or diarrhea with signs of blood, so any change like this would be cause for concern and important to notify a veterinary care provider of.
In cats, these effects are uncommon, but more likely to happen if inappropriately high doses are used. If there are any concerns for toxicity from budesonide, make sure to contact your veterinarian, ASPCA Animal Poison Control (1-888-426-4435) or the Pet Poison Helpline (1-855-764-7661). A fee does apply, but your vet will often find a toxicologist’s advice helpful in developing a treatment plan for your cat.
When using any steroid, it is extremely important to avoid use of non-steroidal anti-inflammatory drugs (NSAIDs). For cats, the most common ones used are robenacoxib (Onsior), and meloxicam (Metacam). Use of NSAIDs and steroids together increase the risk for gastrointestinal erosion and ulceration.
Budesonide for Cats Dosage
When it comes to determining the right dosage, Budesonide is a little tricky, because the dosage is not based on weight but on body surface area. Kirsten McCarthy / Cats.com
Budesonide is a little tricky to dose, because the dosage is not based on weight but on body surface area. It is always best to have your veterinarian determine dosing.
The human formulations of budesonide capsules, like the brand Entocort, are typically too high in dosage for cats. The lowest human dosage starts at 3mg, but most cats will be dosed closer to 1mg or less. For this reason, budesonide is most often ordered through a compounding pharmacy to achieve a safe and appropriate dose.
Conclusion
Budesonide is a great alternative glucocorticoid steroid to use in cats with chronic inflammatory enteropathies/inflammatory bowel conditions where use of a more systemically-acting steroid may cause concerns, such as with diabetes or heart disease.
It is a potent steroid, but only acts locally in the digestive tract, making it a poor choice for many other conditions responsive to steroids. Make sure to discuss with your vet if you think your cat may benefit from use of budesonide.
Drug Dosing Disclaimer: We are only able to provide doses for medications that are FDA approved for use in cats and only as the label guidelines dictate. For medications that are used off-label we can only provide guidelines and safety information for use. Safe and appropriate dosing for off-label medications can only be determined by a primary care veterinarian.
We encourage you to work with your veterinarian to determine if a particular medication is appropriate for your cat. Changing or adjusting a dose for your cat on your own without consulting with a veterinarian can carry risk. We do not encourage use of medications prescribed for human use in pets without first consulting with a primary care veterinarian.
Frequently Asked Questions
What Does Budesonide Do for Cats?
Budesonide is a glucocorticoid steroid that acts more locally in the digestive tract to suppress inflammation and immune-mediated disease. It is often used as an alternative in cats suffering from chronic inflammatory enteropathies/inflammatory bowel disease where use of systemically acting steroids like prednisolone would be undesirable. The most common situations are in cats at risk of or suffering from, diabetes and/or heart disease.
How Long Does It Take for Budesonide to Work in Cats?
Absorption rates in cats do not appear to have been officially studied, but in dogs, concentrations reach their peak in about 1 hour. In people, the peak absorption is variable, taking up to 12 hours.
Practically, with any chronic inflammatory condition affecting the digestive tract, it may take a few days to see reduction in signs like vomiting or diarrhea. In cases where a cat has lost weight due to a condition like IBD, it may take a couple of weeks to see weight gain develop.
What Are the Long-Term Side Effects of Budesonide?
Long-term side effects in cats appear to be uncommon, as long as budesonide is dosed properly. Systemic effects common to steroids like increased drinking, urinating, appetite, panting, hair loss, etc., are typically not seen with budesonide because of its more locally acting effect in the digestive tract and low systemic concentrations.
It is possible, especially if high doses are used, to see side effects limited to the digestive tract, like bloody vomit or stool (a coffee grounds appearance and black tarry appearance respectively), from erosion or ulceration of the stomach and intestinal lining.
Can Budesonide Cause Diabetes in Cats?
Typically, no, and in fact if a cat with diabetes is found to have an inflammatory bowel condition, budesonide would be a top choice for treatment because it acts more locally in the digestive tract and has far fewer systemic effects in the body.
Diabetes in cats is seen almost exclusively in kitties who are overweight or obese, where their bodies have developed insulin-resistance. This is similar to type II diabetes in humans. The reason systemic steroids, like prednisolone, can contribute to diabetes, is that they also contribute to insulin resistance, which can tip a cat already at risk over the edge.
However, when used appropriately, budesonide’s locally acting properties limited to the digestive tract keep it largely out of systemic circulation, far reducing the risk for it to contribute to insulin resistance and subsequent diabetes.
Hello Dr. Vanderhoof,
I wanted to give you an update following Shadow’s follow-up ultrasound today.
The results were very encouraging. The duodenal wall has continued to improve and now measures 2.3 mm. For comparison, it measured 5.6 mm on the initial ultrasound performed on April 27 and 3.2 mm on the follow-up study on June 1.
The ultrasound report states that the duodenum no longer shows wall thickening. The surrounding duodenal-pancreatic lymph node is now normal in size, and the remainder of the intestines appears unremarkable. No other significant abdominal abnormalities were identified.
Clinically, Shadow is doing very well. Since starting budesonide, the vomiting has completely resolved, and Shadow feels much better overall.
Shadow has been receiving 1 mg of budesonide daily. His body weight has increased from 4.1 kg to 4.9 kg, which I am very happy about.
Given the continued improvement on ultrasound and clinically, it seems that a gradual dose reduction may now be possible.
Thank you again for your previous advice and encouragement. Reading about Annie’s long-term success with budesonide gave me a lot of hope, and I wanted to share this positive update with you.
Warm regards,
Katarzyna
Hi Katarzyna,
Those results certainly are encouraging. I’m glad to hear things are going well so far.
Hello Dr. Vanderhoof,
Thank you so much for your thoughtful and detailed reply — it truly means a lot to me, especially as a worried cat owner.
Reading about your cat Annie and her doing well on budesonide for over 4 years honestly gave me a lot of hope. It’s very comforting to hear real-life experience like yours.
My cat has inflammation localized to the duodenum, confirmed on ultrasound with wall thickening, decreased echogenicity, and partial loss of normal layering. Since the initial ultrasound performed on April 27, the wall thickness has decreased from 5.6 mm to 3.2 mm, and the associated lymph node has also reduced in size. A follow-up ultrasound on June 1 confirmed this improvement.
Based on these findings, my cat was recently transitioned to budesonide, and I am hopeful that it will help maintain the improvement we have already seen.
Prior to starting budesonide, my cat was vomiting almost daily, and there was often a noticeable ammonia-like odor from his mouth. Since starting treatment, both have improved significantly.
We have a follow-up abdominal ultrasound scheduled for July 20, and I am hopeful it will show further improvement.
If you don’t mind me asking a couple more questions — what dose did you start Annie on at the beginning of treatment?
Also, is Annie still receiving the same dose, or were you eventually able to reduce it? If so, after approximately how long did you decide to taper the dose?
Thank you again for your kindness and for sharing your experience — I really appreciate it.
Best regards,
Katarzyna
Sure Katarzyna, I’m glad your cat has shown some good improvement on budesonide so far. That is a very thick intestinal wall measurement for a cat. Very important to monitor that with ultrasound, especially with the partial layering loss in the wall, so I’m glad to hear there is a follow-up already scheduled. That appearance can be consistent with very severe inflammatory bowel, some feel small cell lymphoma may have that appearance, though the two may really be two variations of the same condition. My perspective on those is to start a steroid like budesonide and see what improvement we get in the wall thickness and appearance and monitor weight (hopefully gaining) and vomiting/diarrhea frequency (hopefully much lower) over a month or two. If improvement is not as expected, a second medication may need to be added. But fortunately it looks like good improvement has been seen for your cat so far and I hope that continues to be the case later this month. My own cat Annie is on 0.5mg once a day. She responded very well to it and I never appreciated any ill effects, so I have never ventured to taper it. These conditions are always about management and never about curing with no expectation that a medication can be stopped. With prednisolone, which has more body-wide effets, I think tapering is much more common because we’re hoping to mitigate long-term effects on the body while still controlling the bowel condition. With budesonide it’s a little different because its effects are more localized. If there were any side effect concerns but the medication appeared to be helping, I do think tapering could be appropriate, either by reducing by 0.1mg or giving it every other day instead of every day.
Hello Dr. Vanderhoof,
Thank you so much for your thoughtful and detailed reply – it truly means a lot to me, especially as a worried cat owner.
Reading about your cat Annie and her doing well on budesonide for over 4 years honestly gave me a lot of hope. It’s very comforting to hear real-life experience like yours.
My cat has inflammation localized to the duodenum, confirmed on ultrasound with wall thickening, decreased echogenicity, and partial loss of normal layering. Compared to the previous study, the wall thickness has decreased (from 5.6 mm to 3.2 mm), and the associated lymph node has also reduced in size.
Based on these findings, my cat recently started budesonide treatment, and I am hopeful that it will help maintain the improvement we have already seen.
Prior to starting budesonide, my cat was vomiting almost daily, and there was often a noticeable ammonia – like odor from his mouth. Since starting budesonide treatment, both have improved significantly.
We have a follow – up abdominal ultrasound scheduled for July 20, and I am hopeful it will show further improvement.
If you don’t mind me asking a couple more questions – what dose you started with for Annie at the beginning of treatment?
Also, is Annie still receiving the same dose, or were you eventually able to reduce it? If so, after approximately how long did you decide to taper the dose?
Thank you again for your kindness and for sharing your experience – I really appreciate it.
Best regards,
Katarzyna
Hello Dr. Vanderhoof,
I came across your comment about your own cat being on budesonide for about 3 years, and it really gave me hope.
May I ask how your cat is doing now? Is she still on budesonide?
My cat has just started this treatment for IBD, and I am trying to understand what long-term management might look like.
In Poland, there is still not much hands-on experience with budenoside in cats, so your personal experience is incredibly valuable to me.
Thank you so much for sharing your knowledge!
Best regards,
Katarzyna
Hi Katarzyna, that’s correct, my own Cat Annie I started on budesonide a little over 4 years ago now. I’ve fortunately found that she’s done quite well with it. She turns 18 next month. Our hospital cat with IBD has also been on it for nearly a year and has been doing well on it too. In both their cases, I had difficulty controlling their vomiting with diet alone. For our hospital cat, he was vomiting a few times a week while Annie was also losing weight. I’ve had an occasional patient not do well with it but the reason isn’t always clear. Prednisolone or budesonide can both be effective, but budesonide is a better choice especially if another health condition is present where a systemic steroid would be detrimental (diabetes, heart disease, kidney disease are the major ones). Fortunately as well, Annie had no other complicating conditions and I’ve been able to give Annie her budesonide once a day in a pill pocket and she’s rarely refused it. I special ordered it through a compounding pharmacy into a small tablet. I hope you find your kitty does well with it.
Started 0.5 mg capsule of budesonide this afternoon and we are very nervous. This article, like most of your articles here, is very helpful so…Thank You.
Hi David,
My own cat has been on budesonide for about 3 years and has done very well with it for her IBD. Every cat and circumstance is different, but fortunately she has not had any issues with it and it made a huge difference in her vomiting frequency and maintaining her weight. I at least hope you find similar success with your own cat.
Just a FYI: Budesonide did not work well for our little Torti. Made her constipated after the first dose. I hesitantly gave her a second dose.
After 29 hours with one small hard and dry bowel movement and observing her straining with no results, I gave her a dose of miralax (a tad over 1/4 tsp). 8 hours after that we got diarrhea with bright red blood followed by vomiting a hairball…poor thing. It was pretty concerning.
I gave her a calming broth I make from Purina Pro Plan Calming Care powder immediately afterwards and food 2 hours later and presently, 12 hours later now, she appears no worse for wear, fairly active and eating normally.
Still watching her closely and waiting for her next bowel movement but we are pretty reassured at this point.