Glucocoricoids Flashcards
Which parts of the adrenal gland produce glucocorticoids?
Zona fasciculata and reticularis
Exogenous glucocorticoids
Clinical application
Negative long feedback loop (HPPA)
Strong inhibitor of hypothal.
Leads to adenohypertrophy
Examples of prodrugs
Cortisone, prednisone, methylprednisone
Aqueous solutions
Soluble esters- Na phosphate or Na- succinate
Given IM/IV in large doses for emergencies
Suspensions
Insoluble esters with opaque consistency- salts
Given Sc or IM, slow onset
Short-acting glucocorticoids (<24 hours)
Cortisol (hydrocortisone) - 1 gluco, ++ mineralo
Cortisone (prodrug)- 0.8, ++
Prednisone- 4, +
Prednisolone- 4, +
Methylprednisolone- 5, +
^^ alternate-day therapy possible
Intermediate-acting (24-48 hrs)
Triamcinolone- 5, 0
Triamcinolone acetonide- 35, 0
Long-acting (>48 hours)
Flumethasone- 15, 0
Dexamethasone- 30, 0
Betamethasone- 30, 0
^^ produce glucocorticoid effects
What drugs produce mineralocorticoid effects?
Aldosterone + fludrocortisone
Mineralocorticoids
Maintains electrolyte homeostasis
Trigger wound healing
Glucocorticoids
Carb, protein and lipid metabolism
Immune and stress response
Major endogenous glucocorticoid is ___________ and mineralocorticoid is _________
- Cortisol
- Aldosterone
Strength of binding determines _________
Potency and duration
Glucose metabolism
↑ gluconeogenesis and glycogenolysis (hyperglycemia)
↓ glucose uptake in peripheral tissues
Insulin resistance
Protein and lipid metabolism
↓ protein synthesis (anabolism)
↑ protein catabolism and lipolysis
Anti-inflammatory effects
Stimulates lipocortin production
Inhibits PL A2 activity
↓ vascular permeability
COX and LOX affected
↓ induced histamine formation
Antagonize toxins and kinins
Immunosuppression
Inducing apoptosis (lymphoids)
Inhibits clonal expression of T and b cells and interferon synthesis
↓ igG and complement, leukocyte accum.
When is Immunosuppression seen?
When medium to high doses are used (treating life threatening conditions)
What does glucocorticoids do to water and electrolyte balance?
Prednisolone and methylprednisolone enhances K+ excretion and Na+ retention
How do Glucocorticoids affect the kidney
↑ renal excretion
↓ intestinal absorption of Ca causing hypocalcemia
How do Glucocorticoids affect bones
Inhibits osteoblasts, stimulates osteoclasts, ↑ parathyroid secretion affecting bone healing
How does Glucocorticoids affect the endocrine system?
Suppression of ACTH, GH and TSH
Glucocorticoids PK
~90% of cortisol reversibly bound to plasma proteins
Bound to albumin
Excreted in urine
Physiological replacement therapy
Adrenalectomized and addisonian dogs and cats
In moderate stress (2-5 times), severe (5-20)
Hydrocortisone or cortisone
Prednisolone or prednisone
Intensive short-term and shock therapy
Improve survival in hemorrhagic and septic shock
Use high dose, water soluble
Antiinflammatory and antiallergic therapy
Pruritic dermatoses
Allergic pulmonary disease
Allergic gastroenteritis
Prednisolone or prednisone (small animals)
Dexamethasone (large animals)
_________ only used in cats
Prednisolone
Immunosuppressive therapy for autoimmune diseases
Immune-mediated thrombocytopenia
Autoimmune hemolytic anemia
Prednisolone and dexamethasone for induction
Chronic palliative therapy
Used when NSAID therapy not working
Chronic arthritis
Hip dysplasia in dogs
Alternate-day therapy
Allows HPAA to recover on “off” days
Prednisolone (short-duration)
Less practical for large animals
Special uses
Topical and intralesional usage
Dermatitis
HPAA suppression
Lymphoma
Acute dermatitis
Hydrocortisone or prednisolone
Chronic dermatitis
Dexamethasone, betamethasone, triamicinolone
Intraarticular administration
Horses to manage joint pain and inflammation (arthritis and bursitis)
Triamcinolone acetonide (osteoarthritis)
Ophthalmic applications
Treating retinitis, choroditis, optic neuritis, orbital cellulitis
Contraindicated in corneal ulcers
Neurological applications
Acute spinal/CNS trauma
Acute cervical pain
Peripheral neuropathies
What syndrome does Glucocorticoids cause?
Cushing’s → PU/PD, symmetric alopecia, ↑ susceptibility to infection, peripheral myopathy, muscle atrophy, body fat redistribution
Adverse effects
Diabetes mellitus
Iatrogenic secondary hypoadrenocorticism
Glycogen accumulation in liver
Slow turnover of enterocytes
Inhibits protective PG
↓ collagen synthesis
Mood/ behavior changes
High doses in horses cause ________
Laminitis