Bethamthasone and dexamethasone

• Have potent glucocorticoid effects with virtually no mineralocorticoid effects.
• These agents are used in instances where glucocorticoid effects (anti-inflammatory, adrenocorticotropic hormone (ACTH) suppression etc.) are desired without the mineralocorticoid effects (fluid retention, hypokalaemia etc.). Some of these indications include: brain swelling, tumour compression, glucocorticoid remediable hyperaldosteronism or other ACTH-mediated hyperaldosteronism.
• Due to its lack of mineralocorticoid effects these agents are unsuitable for the management of adrenal crisis. However, this is negated when fludrocortisone is added. It is advised when a total daily dose of the equivalent of <100mg hydrocortisone is used, fludrocortisone should be added in cases of primary (not secondary) adrenal insufficiency ( in secondary adrenal insufficiency, the mineralocorticoid levels are maintained by the renin/aldosterone system which functions independently from the pituitary axis).
• These agents also cross the placenta, resulting in premature fetal lung maturation. As such, they are unsuitable for long term steroid replacement in females who are pregnant or planning a pregnancy.
• Dosing: these agents have long half-lives and therefore may be given daily to meet physiological requirements of glucocorticoids. Adjust dosages according to clinical effect.
• Monitoring: patients should be monitored for symptoms and signs of either over replacement (weight gain, glucose intolerance, striae, osteoporosis etc.) or under replacement (weight loss, lassitude, hypotension etc.)
• These agents are not detected by immuno-assays detecting cortisol and may therefore be utilised in dynamic testing for cortisol excess. Although dexamethasone has been studied in this regard, considering the very similar pharmacokinetics of the 2 agents, betametasone is a suitable alternative.

Hydrocortisone

• It is the only preparation that is measurable by conventional immune-assay. This makes it the preferred agent to use for replacement therapy in adrenal insufficiency as it can be monitored. It is also the closest formulation to endogenous cortisol, which also makes it ideal for replacement therapy.
• Hydrocortisone can, however, be used for any condition requiring anti-inflammatory action at much higher doses than those used for replacement therapy. It has a rapid onset of action, therefore it the preferred agent for acute anti-inflammatory indications such as asthma or anaphylaxis.
• Dosing: It has a short half-life, which requires frequent dosing (2-3x/day).