Budesonide-Related Iatrogenic Cushing's Syndrome in Microscopic Colitis.

Budesonide is the treatment of choice for microscopic colitis because of its excellent risk to benefit ratio. It is a potent, well-absorbed corticosteroid, but because of a high rate of first-pass metabolism in the liver, its systemic bioavailability is low. It has fewer corticosteroid-related adverse effects than prednisone, and adrenal suppression is considered to be rare. We present a middle-aged woman with lymphocytic colitis whose symptoms responded to budesonide but developed budesonide-related iatrogenic Cushing's syndrome. Withdrawal of budesonide led to restoration of normal pituitary-adrenal responsiveness but at the price of recurrent diarrhea due to re-emergence of lymphocytic colitis.