Steroids Flashcards
What are corticosteroids derived from?
cholesterol
How can the class steroids be divided?
Glucocorticoids = cortisol
Mineralocorticoids = aldosterone
Sex steroids
How can corticosteroids be administered?
IV = methylprednisolone
Oral = prednisolone
Inhaled = beclomethasone
Topical = betamethasone
How does corticosteroid effect the immune system?
Inhib B/T cell
Reduce transcription of cytokines
Reduce phagocyte function
Immunosuppression
Anti-inflam
Outline the major signalling role of corticosteroids
Lipid sol = can cross cell mem
Bind cytoplasmic receptor = heat shock protein dissociates = activated receptor into nucleus = bind hormones response element in DNA
Bind DNA hormone response element directly
HRE = switches ON/OFF protein transcription = effect
Briefly outline the pathway and feedback of the HPA axis
Hypothalamus, CRH, AP, ACTH, adrenal cortex
Cortisol = -ve feedback to AP/hypothalamus
Outline the physiological actions of Glucocorticoids
Stim glycogenolysis, gluconeogenesis
Hyperglycaemia
Proteinolysis
Lipolysis (low conc)
Lipid deposition (high conc)
Redistribution of fat
What are the clinical uses of steroid drugs?
Inflam disease = asthma, GI disease, inflam skin, nephrotic syndrome, vasculitis, RA
Immuno-suppression = low level
Malignancy = with other chemo agents
Adrenal insufficiency = replace hormones
Cushings disease diagnosis = dexamethasone suppression test
Preterm birth = stim pneumocytes T2 prod of surfactant, reduce RDS
What drugs would be prescribed for adrenal replacement therapy?
Hydrocortisone = cortisol
Fludrocortisone = more selective for mineralocorticoid receptors = aldosterone
Outline the side effects of corticosteroids
Mineralocorticoid (due to cross over of receptor binding) = fluid retention, hypertension, hypokalaemia
Decreased keratin prod = thin skin
Reduced osteocalcin = reduced osteoblast/increased osteoclast = osteoporosis
Increased infections
DM
Stunted growth
Psychoactive effects = seen more in anabolic steroid abuse
Cushingoid features = central obesity, buffalo hump, purple striae
HPA axis is switched off
Outline glucocorticoid general pharmacokinetics
Oral steroid have similar bioavailability
Hepatic/renal clearance – but decreases with age
Describe monitoring and controlled reduction of therapy in long term patients
Long term use = HPA axis switched off
Sudden reduction in drug use = hypoadrenal crisis
= hypotension, hypoglycemia, hyponatraemia, hyperkalaemia, severe dehydration, death
