VPT 311: General and Systemic Veterinary Pharmacology (2+1)

GENERAL PRINCIPLES IN CORTICOSTEROID THERAPY 

1. Glucocorticoids are only palliative and do not provide complete cure
2. Individual variations occur between patients in their response to glucocorticoids therapy and hence dose needs to be individualized.
3. Initial dose depends on severity of the disease. Start with a high dose in severe illness and gradually reduce as clinical signs subside while in mild cases start with the lowest dose and enhance the dose as per need.
4. Prolonged therapy at high doses for several weeks may cause adrenal atrophy.
5. Glucocorticoids even at physiological dosage may result in suppression of Hypothalamo-pituitary-adrenal axis
6. It should preferably be administered locally rather than systemically since low systemic level minimally interferes with cortical ativity.
7. Glucocorticoid therapy should not be terminated abruptly since it may induce hypoadrenocorticism. Dosage should be terminated gradually over a period of 2 weeks.
8. Anti-inflammatory and anti-allergy therapy
   • Large proportion of drugs are used in veterinary practice to combat inflammation or allergy
   • Valuable in the treatment of chronic disease occurring periodically and in the absence of known causes
   • Used in the treatment of chronic arthritis, tendonitis, bursitis, conjunctivitis, dermatitis, pruritic dermatoses, allergic pulmonary disease and allergic gastroenteritis.
   • May be used for short periods for short periods in anaphylaxis, angioneurotic edema, urticaria and serum sickness.
9. It should be used with caution in case of infectious disease, since glucocorticoids will promote dissemination of infectious organism throughout the body resulting in fulminating infectious condition. It is indicated along with antibiotics that are effective in the treatment of underlying infection.
10. Glucocorticoid reduces collagen synthesis and thereby reduces the rate of wound healing. Glucocorticoids are indicated in the treatment of traumatic wound of prepuce of bulls so as to prevent rapid healing that would lead to stricture formation.
11. As a physiological replacement it is used for treatment of Addison’s disease (Chronic adrenal insufficiency) and acute adrenal insufficiency in human beings.
12. Glucocorticoids at high dose induces parturition and can be used to induce parturition in cows, ewes etc. However, since they have teratogenic effects during early pregnancy, it should be used with caution in pregnant animals.
13. Therapy of shock: Early treatment of glucocorticoid improves hemodynamics and enhances survival in hemorrhagic and septic shock but contraindicated in chronic sepsis because of its immunosuppressive effects
14. It can be used to treat depressive states of pet animals and even temperamental dairy cows since it induces euphoria.
15. It depresses immune system. It suppresses B lymphocytes proliferation and T lymphocytes activation. Immune-mediated thrombocytopenia, autoimmune haemolytic anaemia, collagen disease like systemic lupus erythematosus, polyarteritis nodosa respond to glucocorticoid therapy. For the same reason, it is contraindicated during vaccination
    • Corticoids are used in large number of inflammatory ocular disease such as allergic conjunctivitis, iritis, iridocyclitis, keratitis as topical instillation.
    • Systemic therapy is useful in the treatment of retinitis, optic neuritis, uveitis.
    • Contraindicated in corneal ulcers since they slow the process of reepithelialisation of cornea.
16. Corticosteroids can be used along with other immunosuppressants to prevent rejection reaction during organ transplantation and skin allograft.