Question: I was on prednisone for another medical condition and have tapered off. It is unclear at this point whether the medication caused Cushing’s symptoms. How long after stopping prednisone do I need to wait to be tested for endogenous Cushing’s?

Answer: Steroid medications are the most frequent form of Cushing’s syndrome. High dose, long term prednisone can induce exogenous Cushing’s in some circumstances. If Cushing’s due to high dose steroids is suspected, a slow taper followed by switch to hydrocortisone and testing of the hypothalamic-pituitary-adrenal axis is usually recommend. Testing usually consists of a morning cortisol value, if this is normal, no further testing is needed.

After adrenal insufficiency is excluded, if a patient is off steroids and endogenous Cushing’s is still suspected by the medical provider, evaluation for hypercortisolism can be done pretty soon. Prednisone metabolites can be measured in the blood for few days, thus we usually wait at least one week to 10 days.

By Dr. Maria Fleseriu, OHSU Pituitary Clinic, Portland, OR, Spring, 2016