Prednisone Interactions

Glycyrrhizin in licorice inhibits the enzyme 11-beta-hydroxysteroid dehydrogenase type 2, prolonging the half-life of glucocorticoids and dramatically amplifying mineralocorticoid effects. The combination potentiates sodium retention, hypertension, and hypokalemia, and has been linked to severe hypokalemic crises.

Glucocorticoids accelerate the catabolism of 25-hydroxyvitamin D, lower active vitamin D metabolites at the gut, and impair calcium absorption. Population data show oral steroid users have more than double the rate of severe vitamin D deficiency compared to non-users.

Glucocorticoids like prednisone impair intestinal calcium absorption and increase urinary calcium loss, contributing to negative calcium balance and accelerated bone loss. This is a depletion-and-displacement effect, not a chemical interaction in the gut.

Prednisone has weak mineralocorticoid activity that promotes renal potassium excretion. Especially at higher doses or with prolonged use, this can cause hypokalemia, which presents as muscle weakness, fatigue, and potentially arrhythmias.