corticosteroids Flashcards
use of CCs in psoriasis
should be avoided or only used under specialist supervision
primary example of mineralocorticoid
aldosterone
Main function, MOA, Effects on Body and Regulation of mineralocorticoids (primary example: aldosterone)
Main Functions: Regulate electrolyte and water balance.
Mechanism of Action: Act on the kidneys to increase the reabsorption of sodium and water, while promoting the excretion of potassium.
Effects on the Body: Helps maintain blood pressure and fluid balance.
Regulation: Primarily regulated by the renin-angiotensin-aldosterone system (RAAS) and potassium levels.
primary example of glucocorticoid
cortisol
Main function of GCs
Main Functions: Influence carbohydrate, protein, and fat metabolism; suppress the immune system; reduce inflammation.
which drug can be used to treat postural hypotension in autonomic neuropathy and why
mineralocorticoid activity of fludrocortisone
- increases BP by reabsorption of water and sodium
- SE include oedema
why is dexamethasone and betamethasone suitable for suppressing corticotropin secretion in congenital adrenal hyperplasia
have little if any mineralocorticoid action and have a long duration of action
dose should be tailored to clinical response and by measurement of adrenal androgens and 17-hydroxyprogesterone.
as with all GCs, their suppressive action on the hypothalamic- pituitary-adrenal axis is greatest and most prolonged when they are given at night.
by reducing ACTH levels, they help lower the production of adrenal androgens, which are often elevated in CAH.
When is the suppressive action on the HPA axis greatest for GCs e.g. dexameth, beta
In common with all glucocorticoids their suppressive action on the hypothalamic- pituitary-adrenal axis is greatest and most prolonged when they are given at night.
How to diagnose Cushing’s syndrome
In most individuals a single dose of dexamethasone at night, is sufficient to inhibit corticotropin secretion for 24 hours. This is the basis of the ‘overnight dexamethasone suppression test’ for diagnosing Cushing’s syndrome.
Negative test = low cortisol in morning blood test, indicating HPA axis is functioning normally
Positive test for Cushing’s syndrome = high cortisol
name 2 CCs that are appropriate for conditions where water retention would be a disadvantage
betamethasone
dexamethasone
which ccs should be avoided for management of septic shock
high dose ccs
but there is evidence that admin of lower doses of HC and fludrocortisone is of benefit in adrenal insufficiency resulting from septic shock
5 side effects of mineralocorticoids
- hypertension
- sodium retention
- water retention
- potassium loss
- calcium loss
mineralocorticoid side effects are most marked with this drug
fludrocortisone
mineralocorticoid side effects are most marked with fludrocortisone, but are significant with the following 3 drugs
HC, corticotropin, tetracosactide
there are negligible mineralocorticoid actions with the high potency GCs betamethasone and dexamethasone, but they do occur slightly with the following three drugs
methylprednisolone, prednisolone, and triamcinolone.
6 SE of glucocorticoids
- diabetes
- osteoporosis (danger esp in elderly as can result in osteoporotic fractures e.g. hip or vertebrae)
- high doses associated with avascular necrosis of femoral head
- muscle wasting
- CC therapy weakly linked with peptic ulcers and perforation
- psychiatric reactions
main way to manage side effects of CCs
- use lowest effective dose for minimum period possible
suppressive action of a CC on cortisol secretion is least when it is….
given as a single dose in the morning
In an attempt to reduce pituitary-adrenal suppression further, what can you do regarding adminsitration of CCs?
total dose for two days can sometimes be taken as a single dose on alternate days; alternate-day administration has not been very successful in the management of asthma.
side effects of CCs - MHRA advice on rare risk of central serous chorioretinopathy with local and systemic administration
- retinal disorder linked to systemic use of CCs, and local aswell
- pt to report any blurred vision and other visual disturbances with CC treatment
- consider referral to ophthalmologist for elevation of possible causes if a pt presents with vision problems
glucocorticoid suppression action on hypothalamic-pituitary-adrenal axis is greatest and most prolonged when they are given…
at night
in most individuals a single dose of …… at night is sufficient to inhibit corticotropin secretion for 24h
dexamethasone
overnight dexamethasone suppression test for diagnosing Cushing’s syndrome
- finds out if there is excess amount of cortisol in body
- after measuring baseline cortisol, dexamethasone is given with the intention of suppressing cortisol
- if it does not suppress after taking dexamethasone at night, it means there is too much cortisol production aka Cushing’s syndrome
why is dexamethasone given to pt to diagnose cushings syndrome
In most individuals a single dose of dexamethasone at night, is sufficient to inhibit corticotropin secretion for 24 hours
therefore if cortisol has not reduced, it means they have the syndrome