Prednisolone and prednisone are corticosteroid drugs that are nearly the same in chemical formulation and effects. When prescribed for dogs, they are mainly used to reduce inflammation. Prednisolone can be helpful for treating allergies, lung disorders such as asthma, skin diseases, spinal conditions, intestinal diseases and more. Prednisolone should only be used when absolutely necessary, however, particularly for long-term use. It can cause many side effects.
Common Side Effects
Veterinarians may recommend a short course of prednisolone therapy for dogs lasting two weeks or less, or on an as-needed basis. Common side effects associated with this type of short-term use include abnormal thirst, increased appetite, diarrhoea, vomiting, panting and restlessness.
Longer use of prednisolone can cause more serious side effects. These may include behaviour changes, thinning of the coat, weakened and wasted muscles, stomach or intestinal ulcers, diabetes, pancreatitis, and kidney or liver damage. Some of these effects can be life-threatening.
Immune System Suppression
Prednisolone in high doses suppresses the immune system. This is beneficial when the drug is prescribed to treat autoimmune diseases in dogs, such as autoimmune hemolytic anaemia, but can decrease the dog's ability to fight infection and disease.
Adrenal Gland Dysfunction
Because the adrenal glands react to the administration of corticosteroids, high doses or long-term use can cause hormone-related health problems. The dog may develop Cushing's disease, in which the pituitary gland releases too much adrenal hormone. If prednisone is discontinued too rapidly, the dog may develop Addison's disease, involving insufficient production of adrenal hormones.
Prednisolone should not be given to pregnant dogs because it can induce labour. It should not be used in combination with non-steroidal anti-inflammatory drugs such as carprofen (Rimadyl), and veterinarians usually recommend waiting a week between switching from one to the other of these drugs.