Glucocorticoids

Synthetic cortisol-like drugs or glucocorticoids have an effect on virtually all tissues and cells in the body. Chronic or prolonged use of these medications is known to cause side effects in cats and dogs. Some of the possible adverse effects of drugs such as prednisone and dexamethasone are listed here.

1. vasoconstriction, sodium retention; increased blood pressure
2. inhibition of fibroblast proliferation; decreased wound healing
3. decreased lymphocyte and macrophage function; immune suppression
4. increased appetite; weight gain
5. increased thirst and urination
6. changes in mood and behavior: depression, lethargy, weakness
7. lowers the seizure threshold
8. suppress the release of ACTH from the anterior pituitary, suppressing the release of endogenous corticosteroids
9. suppress the release of thyroid-stimulating hormone, follicle stimulating hormone, prolactin, and luteinizing hormone
10. increased levels of parathyroid hormone
11. inhibition of osteoblasts (bone remodeling cells)
12. reduced activity of vasopressin (antidiuretic hormone) at renal tubules causing diuresis
13. antagonizes insulin binding to cell receptors
14. inhibition of platelet aggregation
15. sequestration of lymphocytes, monocytes and eosinophils in the lungs and spleen
16. decreased removal of senescent red cells
17. increased secretion of gastric acid, decreased mucus production
18. decreased proliferation of mucosal tissue
19. decreased absorption of iron and calcium from the diet
20. increased absorption of fat
21. increased deposition of fat in liver cells
22. increased ALT (alanine aminotransferase) and GGTP (gamma glutamyl transpeptidase) activity
23. increased serum alkaline phosphatase
24. decreased numbers of circulating lymphocytes; inhibition of lymphokines
25. inhibit the migration of neutrophils, macrophages and monocytes
26. reduced production of interferon (an antiviral compound)
27. inhibit phagocytosis, chemotaxis, and antigen processing
28. stimulate gluconeogenesis, lipogenesis (blood glucose, fat synthesis)
29. redistribution of fat from the extremities to the trunk
30. increased oxidation of fatty acids
31. increased levels of triglycerides and cholesterol
32. increased catabolism of protein and muscle tissue, causing muscle weakness
33. inhibition of growth hormone
34. increased calcium excretion in the urine
35. inhibition of vitamin D activation
36. decreased growth of fibrocartilage (repair tissue)
37. increased intraocular pressure leading to cataracts and glaucoma
38. increased potassium excretion
39. increased resorption of sodium and chloride from the kidneys
40. thinning of skin and hair, skin atrophy
41. appearance of a dull, dry hair coat
42. secondary disorders: pancreatitis, hepatic lipidosis, Addison's disease, diabetes mellitus, gastrointestinal ulceration, lipidemia, depression, lethargy, weakness, vicious behavior, viral and bacterial infection

Adapted from: Plumb, DC. Veterinary Drug Handbook, PharmaVet Publishing, White Bear Lake, Minnesota. 1991

Natural medicine
In veterinary practice there are many natural alternatives to glucocorticoids that are safe, low cost, and effective. These natural medicines act upon the same metabolic pathways as the steroidal anti-inflammatory drugs, but are readily cleared by the body leaving few if any harmful residual effects. Natural products that reduce inflammation can be found in the pharmacopeia for traditional Chinese medicines, Ayurvedic herbs, Western herbs, and homeopathic remedies. Many food constituents have potent anti-inflammatory and immune modulating effects as well. For example, the fatty acids (eicosapentaenoic acid and decosahexaenoic acid) from marine fish are known to have a beneficial effect by promoting the synthesis of anti-inflammatory prostaglandins.

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