Which mineralocorticoid is used for replacement in primary adrenal insufficiency and what parameter should be monitored?

• A. Fludrocortisone; monitor blood pressure, electrolytes (Na+, K+) and renin if needed.
• B. Hydrocortisone; monitor blood sugar
• C. DHEA; monitor mood
• D. Spironolactone; monitor creatinine

Answer: (A)

A mineralocorticoid replacement is needed in primary adrenal insufficiency because aldosterone production is impaired, so you must provide a drug that supplies mineralocorticoid activity. The best choice is fludrocortisone, which is specifically used to replace aldosterone and help regulate sodium and potassium balance and extracellular fluid volume.

Monitor how the patient responds to therapy by watching blood pressure and electrolytes, especially sodium and potassium. These parameters reflect the effectiveness of mineralocorticoid replacement, since aldosterone promotes sodium retention and potassium excretion. Renin levels can also be used to fine-tune dosing: high renin indicates under-replacement, while a normalized or low renin suggests adequate replacement. In short, aim for stable blood pressure with normal Na+ and K+ and adjust the fludrocortisone dose based on these findings, using renin as a guide when needed.

Hydrocortisone is primarily a glucocorticoid replacement with some mineralocorticoid activity, but fludrocortisone is the specific mineralocorticoid used for Addison’s disease. DHEA is not a replacement for adrenal hormones, and spironolactone would not serve as replacement (it blocks mineralocorticoid receptors).