In my work as a veterinarian, I’ve come across a spectrum of opinions about giving corticosteroids (a.k.a. “steroids) to cats. On one end of the spectrum are people who think steroids are pretty much a cure-all for most cat diseases. On the other end are vets and cat owners who believe steroids are the devil and should never be used for cats. 

You’ve come here asking, “How long does a steroid shot last in a cat?”

Depending on the drug given, the shortest duration of a steroid shot in cats is 1-3 days. A steroid having a medium duration lasts around 7 days and long-duration steroid shots last up to 90 days. The only way to know the duration to expect is to ask your vet which drug your cat received and consult the table below.

If your cat has asthma, allergies or eosinophilic granuloma complex they will probably get steroids at some point. Since most cats hate taking oral medication, steroid shots are the best way to get the medicine into them without a lot of stress. 

There are several different forms of injectable steroids for cats. The most common are dexamethasone sodium phosphate, prednisolone acetate (Meticortelone Acetate®), triamcinolone (Vetalog®), and methylprednisolone acetate (Depo-Medrol®). See the table below for more detail on these medications and a few other injectable steroids used for cats.

How Long Does a Steroid Shot Last in a Cat? 

There is no universal answer to this question as the length of time a steroid shot lasts in a cat will depend on the specific steroid and the individual cat. The table below shows the approximate duration of action for the three most common injectable steroids used in cats. 

Injectable Corticosteroid DrugDuration of Action
Prednisolone succinate1-2 days
Dexamethasone sodium phosphate3-5 days
Prednisolone acetate5-7 days
Triamcinolone acetate7-14 days
Methylprednisolone acetate30-90 days

What are Steroid Shots Used for in Cats?

Corticosteroid injections are used to treat inflammation and immune-mediated disease in cats. Some of the conditions treated include:

  • Allergic dermatitis
  • Eosinophilic granuloma complex
  • Asthma
  • Cancer
  • Immune-mediated anemia
  • Arthritis
  • Trauma
  • Chronic pancreatitis inflammation
Syringe and vial (how long does a steroid shot last in a cat)

How Often Can a Cat Get a Steroid Shot? 

There is no set answer to this question as the frequency of steroid injections will vary depending on the specific situation. Severe, acute conditions like immune-mediated anemia usually require more frequent repetition of steroid shots. A very sick cat may need an injection every few days, depending on which type of steroid is used. 

Milder, chronic conditions like feline asthma may require an injection every 2-4 weeks during flares of the disease. 

Veterinarians often try to use other treatments to minimize the need for repeated steroid shots for cats with asthma and allergic dermatitis. Cats with asthma often benefit from inhaled steroids and topical steroids can help skin allergies.  

How Does a Steroid Shot Affect a Cat? 

Corticosteroid medications are synthetic versions of the hormones produced naturally in a cat’s body. These drugs have many physiological effects including 

  • Alters fat metabolism
  • Increases protein breakdown
  • Antagonizes insulin
  • Suppress inflammation
  • Suppresses immune system function (at high doses)
  • Influences electrolyte balance

What you’ll see as a cat owner can include increased thirst, increased appetite, increased urination, occasionally diarrhea and possibly weight gain when used for a longer time.

The most common use of steroids in cats is the suppression of inflammation associated with feline asthma and allergic skin conditions. When used correctly, steroids can improve a cat’s quality of life without causing unwanted side effects. This can be a real balancing act since cats are fairly sensitive to steroids. 

Can a Steroid Shot Kill a Cat? 

A steroid shot can kill a cat if the dosage is too high or if the medication is given for a long time (months to years). It can also be deadly if a cat has a pre-existing health condition that makes them susceptible to the side effects of steroids. 

There are two deadly situations I’ve seen when it comes to cats and steroids. One happens There are two deadly situations I’ve seen when it comes to cats and steroids. One happens suddenly and the other has a slow onset. The sudden condition is congestive heart failure. Some types of steroids cause extracellular hyperglycemia and increase a cat’s plasma volume, putting more stress on the heart. (1) A cat on the verge of heart failure could be pushed over the edge after a steroid shot.

The other deadly reaction to steroids is diabetes mellitus. As I mentioned above, corticosteroids antagonize the action of insulin in allowing blood glucose to enter cells. Feline diabetes occurs when glucose stays in the blood instead of getting into cells to provide energy. 

I have especially seen steroids cause diabetes when overweight cats are given long-acting steroid injections like Depo-Medrol. Sometimes the condition is reversible, but not always. 

Although oral steroid medication can also lead to these deadly problems, it’s more likely to occur with long-acting injections. Cats taking oral medication can stop taking the meds as soon as the adverse effects are noticed. On the other hand, once a long-acting steroid injection is given, there is nothing your vet can do to reverse the effects.

How Long Does It Take for a Steroid Shot to Work on a Cat? 

Most cat owners notice a change in symptoms within a few hours to a couple of days after a steroid injection. It depends on the condition being treated and the type of steroid injected. 

Cats with asthma and skin allergy symptoms often feel better within 12-24 hours after a steroid injection. If your cat is no better after 3-4 days, you should contact your vet and let them know. They may prescribe a different treatment or recommend further diagnostic testing to better understand your cat’s condition. 

Are Steroid Shots Bad for Cats? 

Steroid shots are both good and bad for cats. Good when used judiciously in the right cases and bad when used excessively without a proper diagnosis. 

The effects of a steroid shot will vary depending on the cat’s health condition. However, in general, steroid shots are not considered to be bad for all cats. Rather, they are seen as a way to help treat specific health conditions in cats.

It has become much less common to give steroids shots to cats as a general anti-inflammatory in the last 20 years. Fortunately, advances in veterinary medicine have produced safer options for treating inflammation in cats these days.  


Steroid shots in cats last anywhere from one to 90 days, depending on which type is used. Most cats show a decrease in clinical signs within 1-3 days, depending on the disease and the steroid given. Steroid shots can cause serious side effects in cats and should be used very carefully. provides content for informational and entertainment purposes. You should always seek care from a veterinarian to diagnose and treat your unique pet. Visit the Privacy Policy and Terms of Use section of this site to learn more.

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  1. Ployngam, T., Tobias, A. H., Smith, S. A., Torres, S. M., & Ross, S. J. (2006). Hemodynamic effects of methylprednisolone acetate administration in cats. American journal of veterinary research, 67(4), 583-587.