Pharm 101: Corticosteroids

Classification
  • Short-medium acting: hydrocortisone, prednisolone
  • Intermediate-acting
  • Long-acting: dexamethasone
  • Mineralocorticoids: fludrocortisone
Pharmacodynamics
  • Act on intracellular glucocorticoid receptors
  • Anti-inflammatory and immunosuppressive effects:
    • Affects concentration, distribution and function of peripheral leukocytes
    • Suppression of inflammatory mediators (cytokines, chemokines)
    • Inhibit macrophages and APCs
    • Inhibit PLA2 –> decrease PG/LT/PAF
  • Catabolic and antianabolic effects
Pharmacokinetics
  • PO, IV, IM, topical administration
  • Cortisol (naturally-occurring):
    • Bound to corticosteroid-binding globulin (CBG)
    • Half-life 60-90 minutes
    • Mostly hepatic metabolism
    • 20% converted to cortisone by kidneys
Relative potency
Drug nameGlucocorticoid activityMineralocorticoid activity
Cortisol11
Aldosterone0.33000
Cortisone0.70.8
Prednisolone40.5
Dexamethasone250

Dexamethasone
  • PO, IV, IM, topical administration
  • Half-life 36-54 hours
  • Compared with hydrocortisone, 30 times more potent, longer acting, and no salt retaining activity
  • Clinical uses:
    • Croup: 0.15-0.60mg/kg PO, single dose
    • Anti-inflammatory effect
    • Anti-emetic
    • Diagnostic testing: dexamethasone suppression test
Hydrocortisone
  • Clinical uses:
    • Acute airways disease
    • Anaphylaxis
    • Thyrotoxicosis
    • Sepsis
Corticosteroids in asthma
  • Mechanism of action:
    • Anti-inflammatory, inhibit production of inflammatory cytokines
    • Contraction of engorged vessels in bronchial mucosa
    • Potentiate effects of beta-receptor agonists
  • Do not directly cause bronchodilation, but reduce bronchial hyperactivity and reduce frequency of exacerbations if taken regularly
Adverse effects of chronic use
  • Insomnia
  • Peptic ulcer disease
  • Acute psychosis
  • Cushings syndrome (> 2 weeks):
    • Metabolic effects (moon face, truncal fat, weight gain, hyperglycaemia)
    • Osteoporosis
    • Hypertension
    • Impaired wound healing
  • Adrenal suppression (> 2 weeks)
Further reading
References
Pharm 101 700

Pharmacology 101

Top 200 drugs

MBBS CCPU (RCE, Biliary, DVT, E-FAST, AAA) Rob is an Emergency Medicine Advanced Trainee based in Melbourne, Australia. He has special interests in medical education, ECG interpretation, and the use of diagnostic and procedural ultrasound in the undifferentiated and unwell patient.

Follow him on twitter: @rob_buttner | ECG Library |

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