6b. Corticosteroids Flashcards
What are corticosteroids derived from?
Cholesterol.
How do corticosteroids act?
Act on intracellular receptors to form hormone receptor complexes and then forms a dimer with another HR complex which acts on nucleus to modulate transcription of associated genes. Affects rate of mRNA expression.
What are the effects on metabolism from glucocorticoid use?
Increased glucose production (increased gluconeogenesis and reduced glucose uptake to muscle and fat), proteolysis to increase amino acid levels, and redistribution of lipids.
What is the action of glucocorticoids on bone?
Inhibit osteoblast formation and reduce calcium absorption in gut.
What is the action of glucocorticoids on the inflammatory system?
Anti-inflammatory and immunosuppressive drugs by inhibition of B and T cell responses, reduced transcription of cytokines, reduced cell adhesion by leucocytes, and reduced phagocytic function.
What disease can result from excess glucocorticoid?
Cushing’s syndrome.
What are the changes seen in Cushing’s syndrome?
Significant fat redistribution, reduced muscle mass (increased proteolysis), hypocalcaemia (affects GI absorption), reduced bone reabsorption, hyperglycaemia, effects CNS.
What are the adverse drug reactions of glucocorticoids?
Cushing’s syndrome, risk of avascular necrosis, cataracts, peptic ulcers, infections, adrenal insufficiency (HPA inhibition), sodium and water retention -> hypertension/hypernatraemia/hypokalaemia.
Which drugs affect glucocorticoid metabolism?
Inducers (PCRABS) - phenytoin, carbamazepine, rifampicin, alcohol, barbiturates, sulphonylureas.
Inhibitors (O-DEVICES) - omeprazole, disulfarim, erythromycin, valproic acid, isoniazed, cimetidine, ethanol, sulphonamides.
Which steroid sparing drugs can be used in conjunction with glucocorticoids?
Azathioprine, methotrexate, cyclophosphamide.
What should be used to monitor long term use of glucocorticoids?
Peak flow, ALT, CRP.
Why is gradual tapering of glucocorticoids doses needed?
Risk of adrenal insufficiency, so need to taper off to allow reactivation of HPA axis.
What are the clinical uses of glucocorticoids?
Inflammatory disease (IBD, RA etc), immunosuppression (acute transplant rejection, etc), malignancy (treats hypercalcaemia and increases appetite), adrenal insufficiency, diagnosis of Cushing’s (Dexamethasone suppression).
Why should the anaesthetist be informed about patients on long-term steroids?
Can’t mount sufficient endogenous stress response so risk of peri-operative hypo-adrenal crisis is a risk so steroid levels should be increased around surgery.
