If dexa has no mineralocorticoid activity, how is it improving hyponatremia?

if dexa has no mineralocorticoid activity, how is it improving hyponatremia??

Dexa has mineralocorticoid activity but the level of activity is low when compared to aldosterone.

Dexamethasone is least preferred alternative if hydrocortisone is unavailable

Dexamethasone has NO mineralocorticoid activity and requires concurrent substitution with fludrocortisone, doses vary between 0.75 -9mg over 24hrs, divided in 2-4 doses, and are titrated to patient response, therefore, an endocrinologist should be consulted

Consider adding mineralocorticoid replacement e.g.,fludrocortisone (off-label) for the following :

  • patients receiving glucocorticoids other than hydrocortisone ( as they have no mineralocorticoid activity)

  • patient’s with septic shock

Cortisol inhibits adh secretion…reason why water intoxication occurs in adrenal insufficiency is cortisol depletion

Hypocortisolism leads to :

Increase ADH level —> retention of free water —> dilutional hyponatremia

Cortisol normally exhibits a tonic inhibitory effect on the secretion of ADH