Eirevet is a veterinarian specialized in canine and feline internal medicine who owns a small animal veterinary hospital in Ireland.
Are Steroids Safe For Pets?
Corticosteroid medications such as prednisolone (prednisone) are widely used in both human and veterinary medicine to treat allergies, cancers, and autoimmune issues such as atopic skin disease, flea allergy, inflammatory bowel disease, and rheumatoid arthritis, to name but a few. Used appropriately, steroids can greatly improve your pet's quality of life while helping to treat serious illnesses.
Unfortunately, steroids are often not used appropriately, either due to incorrect or incomplete diagnoses or due to owners' lack of understanding of the potential side effects of medications such as prednisone.
The following discussion aims to inform readers of these side effects and suggest possible methods to reduce steroid use in some specific conditions.
Common Side Effects
Corticosteroids are produced naturally in the adrenal glands and have a number of important functions in a healthy pet. Cortisol, the predominant naturally occurring steroid, has
- anti-inflammatory functions
- homeostatic functions
- immune-modulating functions
These beneficial effects are dependent on the proper functioning of feedback mechanisms between the adrenal glands, pituitary gland, and hypothalamus. The low levels of endogenous steroids are constantly fine-tuned by communication between these organs. When communication breaks down, an animal may develop serious problems such as Cushing's Syndrome or Addison's Disease.
When we administer corticosteroids in the form of prednisolone or prednisone, we override this sophisticated feedback mechanism and are likely to cause at least some mild symptoms of Cushing's Syndrome. These signs are discussed below.
Effects of prednisone vary from one animal to the next, and while some pets will become agitated, hyperactive, or even aggressive, it is most common for owners to notice lethargy and reduced energy levels. While some of this effect seems to be due to a direct effect on the brain, exercise intolerance because of muscular and respiratory effects are likely to also play an important role.
Steroids Cause Increased Thirst and Urination
Corticosteroids have a massive impact on the body's ability to conserve water, increasing fluid loss through urination by several mechanisms. Increased levels of glucose in urine draw out water through the kidneys, while mineralocorticoid effects alter electrolyte levels, driving thirst and increasing excretion.
For these reasons, it is very common to notice an increase in water intake, and it is also possible that your well-trained indoor dog may start leaving puddles of urine in the house due to an increased frequency of urination coupled with weaker control of the bladder sphincter muscles.
Steroid Medications Make Your Dog Hungry
As mentioned above, a pet receiving steroids will experience mild-to-moderate diabetes symptoms. By reducing the effects of insulin in the body, prednisone will increase blood glucose levels, while reducing the body's uptake of nutrients (in lean tissues) and creating a feeling of hunger.
Unfortunately, corticosteroids also encourage the deposition of fat, so while pets with true diabetes will lose weight, those on prednisone and prednisolone will actually gain weight in the form of fat, while losing muscle mass.
Steroids Cause Muscle Wastage
As alluded to above, dogs on steroid treatment will exhibit marked muscle wastage. This is often most evident in the temporal muscles, giving the face and forehead a 'sharper' appearance. Loss of muscle strength in the abdominal wall leads to a characteristic pot-bellied appearance (as above), and muscle loss in the limbs contributes to exercise intolerance.
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Another common complaint from owners is that their pets pant excessively; this again is due to muscle weakness in the chest wall and diaphragm, while house-soiling is at least partly due to effects on the sphincter muscles.
A rare complication of treatment is corticosteroid myopathy, which is a very painful condition due to depletion of intracellular levels of carnitine in skeletal muscle. If identified early, this can usually be rectified by a reduction of dose and initiation of carnitine supplementation.
Side Effects on Skin and Hair
Although prednisone (prednisolone) is most often prescribed for skin disease, high doses can cause undesirable effects on coat and skin quality. Comedones (blackheads) are commonly seen, while skin thinning and fragility can cause striae (stretch mark) formation or even skin tearing in severe cases.
Calcinosis cutis, the deposition of calcium within the skin, can occur with very high doses, and can cause unsightly hard lumps to develop, often erupting through the skin surface.
Hair loss and a failure of hair to regrow following clipping are also extremely common effects.
Steroids Cause Immune Suppression
As well as causing the death of certain white blood cells (lymphocytes), corticosteroids inhibit communication between the components of the immune system, making unwanted bacterial infections a common complication of treatment.
Dental and urinary tract infections are most commonly seen, and any pet receiving long-term steroid medication should have regular oral examinations to detect the early stages of periodontal disease and hence prevent tooth loss. Regular monitoring of the pet's urine is also recommended to detect urinary tract disease, which often exists without obvious signs.
Less Common Side Effects of Steroids
Can cause myocardial thickening (rare)
Liver & Pancreas
Hepatic lipidosis, pancreatitis
Hepatic lipidosis, pancreatitis
Vomiting, diarrhea, ulceration
Vomiting, diarrhea, ulceration
Blood clots / stroke
Blood clots / stroke
Reducing the Need for Steroid Medication
The key to reducing all of these unwanted side effects is to reduce the dose of steroid being administered. Your veterinarian should be advocating complementary therapies for your pet's primary problem in order to achieve this. These other therapies will vary depending on the specific problem being treated.
Almost all pets with autoimmune or allergic problems will benefit from Omega 3 fish oil supplementation (see above). These oils are powerful anti-inflammatories and provide some protection from adverse steroid effects.
When dealing with allergic skin disease, it is crucial that any concurrent bacterial and fungal infections are controlled with appropriate topical and systemic treatments. Malaseb is a very useful shampoo when managing the first presentation of skin disease or when skin flares up, while a protectant shampoo such as Allermyl should be used for maintenance washing.
Pets with digestive problems will usually benefit from dietary change, meticulous parasite control, probiotic treatments, and low-dose antibiotic treatment. While steroids will usually still be required, the dose will often be greatly reduced.
Finally, one should be aware that steroids need not be used in isolation for treating any of these ailments. While prednisone and prednisolone will usually be the first-line treatments, other drugs such as oclacitinib, ciclosporine and azathioprine can often be used in combination to reduce side effects.
As a veterinarian, I can say without a doubt that countless animals would lead poorer lives without the availability of steroid medication for the treatment of many common conditions. However, there is much scope on the parts of both veterinary surgeons and owners to exercise greater care in their use and to explore alternative treatment options in order to minimise potentially harmful side effects.
Supplements for Pets on Steroid Treatment
This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
Please Share Your Experiences of Steroid Treatments
Jane Dumic on April 23, 2019:
My dig was on steroids because of mms, she was weaned off but I'm strugling to reduce her weight. She does not eat much but seems to be obese.
Addie W on December 17, 2017:
My dog has been diagnosed with ITP a month or so ago. Been on Pred 20 twice a day and Atopica. Now they say her blood work looks good except elevated liver.
Is the Pred or Atopica the cause? And how should I taper back? She was critical at onset I spent thousands saving her. I put my family in financial crisis. I cant afford continued vet apt. To tell me more tests if it is that I shoued ween off drugs. And the Atopica is very expensive! So which one is it doc? Pred. Or Atopica causing this? Right now we had decided to ween off I wanna know how to do it... and to pay close attention to her reactions, and go for blood work every few weeks..
So pls tell me how to ween off. From reading I think Omega 3 should be introduced to replace pred, and melatonin for platelet support. Pls advises asap.
My primary vet that referred us to internal medicine kinda leaves it up to them and I am not impressed. They tell me to get blood test for dog there and they will get results and then they tell me they want a follow up with the dog and then do the same blood wk and additional procedures its too much! Emotionally draining. Financially killing. Her liver and everything was fine until the meds and I told the dr. I had learned one of these meds could effect liver and she was like oh no hasn't been seen and here we are!! Only thing noticeable is her whites of her eyes are a little dirty not yellow. She hasn't gotten pot belly or crazy eating. Drinking yes, appetite good, muscle loss around head yes. Happy wagging tail yes and little skip in her step yes.. She is 10 Please help. I know I can do this! With some proper outside advice..
Janice Kay on September 27, 2017:
Causing skin issues and fatigue. Wish I could find something for colitis besides steroids.