Most folks know what cortisone and hydrocortisone is. These are steroids or a very potent anti-inflammatory drug used for a range of conditions. While steroids are commonly prescribed to both people and animals, long-term use comes with serious complications.

Steroids can be used to treat many types of diseases and at different doses can work as an anti-inflammatory or an immunosuppresive agent. Steroids can be short-acting, long-acting, intermediate-acting, oral, injectable, topical, or even inhaled. With so many uses possible, it is important to know which effect(s) your doctor is going for.

A cholesterol based molecule
A cholesterol based molecule 

Some things to know:

Steroid: A hormone with a cholesterol-based structure is a steroid hormone. There are sex steroids (like anabolic steroids that body builders and athletes use (but probably shouldn’t) and there are cortisol  based steroids, which do not build muscle but work to suppress inflammation and at higher doses, the immune system. 

Corticosteroid: Also called an adrenal steroid is produced by the adrenal gland. There are two types: glucocorticoids (which address sugar metabolism) and mineralocorticoids (which address electrolyte metabolism). We are concerned with the glucocorticoids for this discussion.

Examples of Glucocorticoids

Cortisol: This is the natural hormone produced by one’s adrenal glands to regulate sugar, fat, and salt metabolism in times of stress.

It turns out cortisol can be made in the laboratory and when it is, we call it hydrocortisone (or sometimes just plain cortisone.) Hydrocortisone is a common topical steroid used in assorted anti-itch products. Modifications of it make it stronger or longer acting such as mometosone, which is used in human nasal products as well as veterinary ear medications. Cortisol can also be given by injection.

Oral Glucocorticoids

Prednisone/Prednisolone: In order for cortisone to become an active hormone, the liver has to convert it into prednisone. Prednisone can be produced in the laboratory and is readily available as a medication.

Methylpredisolone (Medrol®): By altering the prednisolone molecule in the laboratory, the potential for side effects can be reduced. One issue is the increased thirst side effect. By changing the prednisolone structure slightly, less salt retention occurs, leading to less thirst compared to what happens with regular prednisolone. Less thirst means less urination and less chance of an accident in the house.

Dexamethasone (Azium®): Adding still more methyl groups creates an even stronger steroid with even less salt retention side effects. Dexamethasone can also be manufactured in the laboratory and is readily available as a medication that can be used topically, orally or as an injectable.

Injectable Steroids

Injectable dexamethasone
Injectable dexamethasone

We have already covered dexamethasone, which can be used as an injectable. Other modifications have led to:

Methylprednisolone Acetate (Depomedrol)This steroid is very strong and can maintain an anti-inflammatory effect for several weeks. This is helpful for patients (especially cats) who may not readily accept oral shorter acting steroids every day.

But the downside is that the injection makes for a high dose that wanes over time and can lead to unwanted side effects such as type 2 diabetes and in some cats, heart failure. While steroids short-term can have benefits, there are serious side effects

Short-Term Side Effects

A pet on glucocorticoids is likely to experience:

  • Increased hunger
  • Increased thirst and possibly urinary incontinence for dogs if there is inadequate access to an area for appropriate urination
  • Panting (dogs)
  • General loss of energy
  • Hidden infection being unmasked, especially upper respiratory infections in cats.

These side effects are generally classified as inconvenient but not serious. If a short-acting oral steroid is being used, often simply changing the dosing schedule solves these problems. If a long-acting injectable is used, you simply have to wait for it to wear off.

But there are also more serious side effects:

  • Pre-diabetic animals may be tipped over into a diabetic state with steroid use. Often in these cases, the diabetes resolves once the steroid wears off.
  • A similar situation exists for patients with borderline for heart function (a situation for which cats are notorious). The extra salt retention from steroid use can prove to be just too much for a heart that can barely manage its normal fluid volume. The salt causes fluid retention and a borderline heart may not be able to manage.

Even these serious side effects can resolve once the steroid wears off, but it is important to be aware of these possibilities. The above scenarios are rare but when they happen to your pet, they will not feel rare to you.

Long-Term Side Effects 

Long term steroid use can results in
Cushing’s Disease symptoms

Many conditions require long-term suppression of the immune system. As previously mention, glucocorticoid doses generally include a lower anti-inflammatory dose an immune-suppressive dose that is higher, though with long enough term use, lower doses can still affect the immune system.

When steroid use stretches out for more than four months, a new set of side effects, in addition to those listed above, becomes of concern:

  • Urinary tract infections occur in up to 30% of patients. Monitoring for these with periodic urine cultures is needed. The patient will not have the usual symptoms of urinary infection as the steroid will suppress the inflammation associated with the infection. Culture may be the only way to detect the infection.
  • Development of thin skin, blackheads, and poor ability to heal wounds or grow hair
  • Development of obesity and muscle weakness
  • Hard plaques of diseased skin called calcinosis cutis. These plaques are calcium being deposited in the skin.
  • Predisposition to infection of any kind/weakening of immune defenses
  • Development of the symptoms of Cushing’s syndrome.

All of the above listed effects can be seen and be considered symptoms of this syndrome.

When long-term therapy is needed, monitoring tests become especially important; requesting refill after refill without regard for the potency of these medications is not appropriate. Periodic urine cultures, check-ups and even blood testing is part of responsible on-going corticosteroid use. Your veterinarian will suggest appropriate tests.

Steroid Alternatives

When a long-term dose of steroids is needed, it is often prudent to look for an alternative medication that will result in similar effects. There are new medications for allergies and itch that can often be used in place of steroids and yield fast results. For alternative immunomodulating drugs, consult your veterinarian.

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