Glucocorticoids

Glucocorticoids
Most glucocorticoids are synthetic analogues of hormones secreted by the adrenal cortex. They exert anti-inflammatory, metabolic, and immunosuppressant effects. Drugs in this class include:
  • beclomethasone
  • betamethasone
  • cortisone
  • dexamethasone
  • hydrocortisone
  • methylprednisolone
  • prednisolone
  • prednisone
  • triamcinolone.
Pharmacokinetics
Glucocorticoids are well absorbed when administered orally. After I.M. administration, they’re absorbed completely.
Distribution
Glucocorticoids are bound to plasma proteins and distributed through the blood.
Metabolism and excretion
Glucocorticoids are metabolized in the liver and excreted by the kidneys.
Pharmacodynamics
Glucocorticoids suppress hypersensitivity and immune responses through a process that isn’t entirely understood. Researchers believe that glucocorticoids inhibit immune responses by:
  • suppressing or preventing cell-mediated immune reactions
  • reducing levels of leukocytes, monocytes, and eosinophils
  • decreasing the binding of immunoglobulins to cell surface receptors
  • inhibiting interleukin synthesis.

Taking the red (and more) out
Glucocorticoids suppress the redness, edema, heat, and tenderness associated with the inflammatory response. They start on the cellular level by stabilizing the lysosomal membrane (a structure
within the cell that contains digestive enzymes) so that it doesn’t release its store of hydrolytic enzymes into the cells.
No leaks, no drips
As corticosteroids, glucocorticoids prevent the leakage of plasma from capillaries, suppress the migration of polymorphonuclear leukocytes (cells that kill and digest microorganisms), and inhibit phagocytosis (ingestion and destruction).
To ensure a job well done, glucocorticoids decrease antibody formation in injured or infected tissues and disrupt histamine synthesis, fibroblast development, collagen deposition, capillary dilation, and capillary permeability.

Pharmacotherapeutics
Besides their use as replacement therapy for patients with adrenocortical insufficiency, glucocorticoids are prescribed for immunosuppression and reduction of inflammation and for their effects on the blood and lymphatic systems.
Drug interactions
Many drugs interact with corticosteroids:
  • Aminoglutethimide, barbiturates, phenytoin, and rifampin may reduce the effects of corticosteroids.
  • Their potassium-wasting effects may be enhanced by amphotericin B, chlorthalidone, ethacrynic acid, furosemide, and thiazide diuretics.
  • Erythromycin and troleandomycin may increase their effects by reducing their metabolism.
  • They reduce the serum concentration and effects of salicylates.
  • The risk of peptic ulcers associated with nonsteroidal anti-inflammatory drugs and salicylates increases when these agents are taken with corticosteroids.
  • The response to vaccines and toxoids may be reduced in a patient taking corticosteroids.
  • Estrogen and hormonal contraceptives that contain estrogen increase the effects of corticosteroids.
  • The effects of antidiabetic drugs may be reduced, resulting in increased blood glucose levels

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