Question

The physiological dose of hydrocortisone (mg/kg/day) is:

• A. 5 mg/kg/day
• B. 10 mg/kg/day
• C. 15 mg/kg/day
• D. 20 mg/kg/day

Hint:

Think basal adrenal output, not a treatment dose - about 10 mg/kg/day.

Answer 1

The Correct Option is B

Step 1: Hydrocortisone (cortisol) is the principal glucocorticoid secreted by the adrenal cortex. The question asks for the physiological (basal replacement) amount, i.e. the body's own normal daily output.
Step 2: The normal rate of secretion of the two principal corticoids is hydrocortisone about 10 mg/kg/day (with nearly half secreted in the early morning hours, following the diurnal rhythm) and aldosterone about 0.125 mg/day.
Step 3: Therefore the physiological dose of hydrocortisone is 10 mg/kg/day, which corresponds to option (b).
Step 4: Why the others are wrong - 5 mg/kg/day underestimates the basal cortisol output, while 15 and 20 mg/kg/day are supraphysiological (pharmacological) amounts used for anti-inflammatory or stress dosing, not basal replacement.