Depo-Medrol for Cats: Uses, Dosage, and Important Risks

Though they sometimes carry a bit of a stigma, steroids such as Depo-Medrol have many important uses in veterinary medicine. So, whether your kitty is seasonally itchy or suffers from asthma or arthritis, they may cross paths with Depo-Medrol. Here’s what you need to know about this medication, including what it’s used for, the potential risks, and alternative medications.

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What is Depo-Medrol?

You usually hear the name “Depo-Medrol” or just “Depo,” but this medication’s true name is methylprednisone. It’s a synthetic glucocorticoid that performs many functions in the body and has been used to treat nearly every illness known to cats.

Glucocorticoids are similar to the steroid cortisol that is normally produced in a cat’s adrenal glands. It impacts the immune system, metabolism, heart and nerve function, and stress responses, to name a few things.

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Common uses of Depo-Medrol in cats

The many functions of Depo-Medrol can be divided into three categories.

Anti-inflammatory

Depo is most commonly used in cats for its anti-inflammatory benefits, especially for chronic conditions such as arthritis or asthma. It may also be used to treat allergies to fleas, foods, or environmenta l factors that cause a lot of itching or skin issues.

Depo-Medrol decreases the body’s immune response to things such as allergens and also increases anti-inflammatory proteins.

Immunosuppression

Along with its anti-inflammatory properties, Depo can also be used at higher doses to suppress the immune system in treatment for autoimmune diseases such as feline stomatitis, post-blood transfusions, or other bad, systemic reactions. It does this by blocking the activation of — or reducing the numbers of — certain white blood cells.

Glucocorticoid replacement

Depo can also be used in cats with Addison’s disease, or hypoadrenocorticism. Here, a cat’s adrenal glands fail to produce enough steroids, leading to negative effects on the immune system, electrolytes, and metabolism. They require replacement steroid therapy, which may include methylprednisone.

Typical administration and dosage

Steroids such as Depo-Medrol should be given at the lowest dose and shortest interval possible in order to decrease the likelihood and severity of side effects. Depo comes in both a pill and an injectable form, but most vets will opt for the injection. (Those of you who have ever tried to give a pill to a cat will understand.)

Injections tend to last a week or more, often giving your cat relief in one dose or allowing repeat doses to be administered every one to six weeks, or when needed. Keep in mind that you should give them Depo as minimally as possible — most vets will cut your cat off after a set number of doses, depending on the issue being treated.

Depo-Medrol is dosed by weight, with most cats needing 10 to 20 mg, which usually equates to one-half to one milliliter given intramuscularly.

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Potential benefits of Depo-Medrol in cats

The most common benefit that vets are trying to achieve with Depo is to decrease inflammation. Chronic inflammation may stem from issues such as arthritis or allergies, causing your cat so much discomfort in the form of pain, itchiness, or swelling. Giving them Depo can drastically decrease inflammation and keep it down for a prolonged time — with just one injection.

The effects it has on the immune system also play a role in its use as an immunosuppressant. When the immune system gets overly active during conditions such as stomatitis, allergies, or systemic reactions, giving your cat Depo can temper that reaction, allowing their body to cope in a more controlled fashion.

Depo may have a few additional benefits, too, including increasing appetite — important for cats experiencing some health concerns, although it isn’t typically used solely as an appetite stimulant. There are better medications for that.

Potential risks and side effects of Depo-Medrol in cats

Steroids are very effective medications that help treat a variety of conditions in cats, dogs, and people. But they aren’t without their faults. 

Most of the time, using Depo-Medrol in your cat may cause:

• An increased appetite

• Increased water consumption

• Increased urination

Long-term or high-dose use of steroids, including Depo-Medrol, can lead to side effects, some of them severe. They may include:

• Weight gain

• Vomiting/diarrhea

• Gastric ulcers

• Dry, brittle haircoat

• Hair loss

• Depression, lethargy, aggression

Depo-Medrol shouldn’t be used in cats with a systemic fungal infection and should be used with caution in cats with diabetes, clotting issues, and heart or kidney disease.

Alternatives to Depo-Medrol for cats

It’s hard to rival the impact of steroids in treating some feline conditions, but there are some kitties out there who just can’t handle them. For those cats, there are other options.

First of all, if your cat’s issue is with methylpredisone, they may be able to get by on a less potent steroid such as prednisolone. However, for severe or chronic inflammation, prednisolone may not cut it, or may need to be given at higher doses. Cats with asthma or other chronic respiratory conditions may benefit from localized steroids — by way of inhaled steroids such as fluticasone — rather than systemic treatment.

Additionally, a non-steroidal anti-inflammatory drug (NSAID) may be of some use, especially for issues like osteoarthritis. Unfortunately, there are only really two options for cats: robenacoxib and meloxicam. NSAIDs come with their own set of risks, so that’s something your vet will need to consider.

To aid in chronic pain management, NSAIDs may be combined with pain medications such as gabapentin or opioids. Autoimmune or allergic issues may respond to immunosuppression from medications such as cyclosporine.

As far as natural products go, omega fatty acids, CBD oil, acupuncture, and laser therapy are options that you can discuss with your veterinarian before trying.

Bottom line

Depo-Medrol is a commonly used steroid injection in cats for issues such as allergic itchiness, asthma, and arthritis. It should be given at the lowest dose and lowest frequency possible to reduce side effects, which can include increased appetite, water consumption, and urination. More severe side effects may include vomiting, diarrhea, lethargy, or aggression.

Speak to your veterinarian about the benefits and risks of Depo-Medrol for your cat, as well as alternative options if long-term therapy is needed.

References

•  “Clinical findings, treatment, and outcomes in cats with naturally occurring hypoadrenocorticism: 41 cases.” Journal of Veterinary Internal Medicine. 11 Dec 2024. https://onlinelibrary.wiley.com/doi/10.1111/jvim.17243.

 “Feline Chronic Gingivostomatitis.” Veterinary Dentistry Specialists. 16 Dec 2020. https://vdsvets.com/feline-chronic-gingivostomatitis.