Prednisone is one of the most widely used medications in veterinary medicine. It is a corticosteroid antinflammatory that binds to inflammatory cells preventing them from causing inflammation. It also suppresses the effect of inflammatory chemicals produced by those inflammatory cells.
One of the most common uses for this drug in veterinary medicine is to treat allergies, which are a very common source of itchy skin for dogs and cats. Some of the most common allergies are flea allergies, inhalant allergies (allergies to pollens, molds and other particles that pet’s breathe in), and food allergies. These allergies cause a great deal of discomfort in pets. They will sometimes itch themselves until they bleed, and then develop secondary skin infections.
The most important approach to allergies is to identify the underlying cause, and to treat the underlying cause, but prednisone is very helpful in the interim to provide relief to the pet. Food allergies and inhalant allergies can be difficult and expensive to diagnose and treat. Prednisone is an inexpensive, effective drug for animals with difficult to control allergies, and for owners that cannot afford more expensive diagnostics or treatments.
When prednisone is used at higher doses it can suppress the immune system to treat a variety of other conditions. Two of the most common are immune mediated diseases and cancer. Immune mediated illnesses are those in which the body’s immune system attacks itself. One of the most common immune meditated diseases in dogs is immune mediated hemolytic anemia. In immune mediated hemolytic anemia the immune system destroys red blood cells and cause life threatening anemia. Prednisone reduces the number of sites on white blood cells that attach to red blood cells and cause the white blood cells to eat the attached cells2. I have also used prednisone to manage a common skin cancer in dogs called mast cells tumors, when the owners could not afford referral to an oncologist. In this case prednisone reduces inflammation, irritation, and pain3. It will also slow the growth of, but will not eliminate the tumor.
One of the drawbacks of prednisone is the side effects. Side effects generally depend on the dose and the length of time that the pet is on the mediation. Even at the lower anti-inflammatory doses used for allergies it will cause your pet to eat more, drink more, and urinate more, sometimes to the point of driving owners crazy. These side effects will however lessen in severity as the patient is weaned off of the medication. If prednisone is given long term it can cause the adrenal glands to shut down, can cause diabetes, and will cause delayed healing and decreased ability to fight off disease. With the higher immunosuppressive doses needed for autoimmune diseases and cancer, prednisone can cause gastric ulceration. When administering at these higher doses I use a medication in tandem with the prednisone that will decrease gastric acid secretion to lessen the possibility of developing stomach ulcers.
Prednisone is an excellent and inexpensive medication, but must be used under the supervision of your veterinarian. Regular monitoring is especially essential when used in high doses or for extended periods.
1. Saunders Handbook of Veterinary Drugs third edition small and large animals; By Mark G. Papich page 645-646
2. Saunders Manual of Small Animal Practice page 172-173
3. Notes from a lecture by Kim Freeman DVM Veterinary Cancer Referral Center