SAT319 Megestrol-induced Adrenal Insufficiency

Disclosure: C. Alcorn: None. P. Subarajan: None. S. Ghaith: None. K. Jordan: None. Introduction: Megestrol, a progestin derivative, is a common drug used for anorexia or cachexia. Chronic use of megestrol can lead to suppression of the pituitary-adrenal axis, causing secondary adrenal insufficiency (SAI). Case: A 93-year-old female with a history of dementia presented with one-week history of confusion and weakness. She was found to have hyponatremia with a sodium of 134meq, consistent with her baseline. CT head and infectious workup were negative. She received 600cc of normal saline and repeat sodium decreased to 124meq/l. Nephrology was consulted due to concern for SIADH. She remained altered and was given a short course of hypertonic saline, 25cc for 4 hours. Repeat sodium after hypertonic saline was 118meq/l. TSH was normal but 8 am cortisol was 1.3 mcg/dL and ACTH level was <1.5 pg/ml. Endocrinology was consulted for evaluation of adrenal insufficiency. Cosyntropin stimulation test was performed with inadequate response, consistent with secondary adrenal insufficiency (SAI). The patient was subsequently given 50mg IV hydrocortisone with improvement in sodium to 125meq/l. The patient had been prescribed megestrol 200mg at home for cachexia. Upon discussion with her family, she was receiving multiple extra doses of megestrol per day for further appetite stimulation. She was only started on 200mg daily dose on admission. It was determined the patient had SAI secondary to megestrol use. This medication was discontinued, and she was initiated on hydrocortisone therapy with endocrinology follow-up. Conclusion: SAI is defined by deficiency of ACTH in setting of hypocortisolemia. SAI is often associated with prolonged glucocorticoid use but can also be seen in patients with pituitary tumors, pituitary surgery, or granulomatous disease. SAI can cause hyponatremia, hypoglycemia, and fatigue but is not typically associated with hypotension or hyperkalemia as the mineralocorticoid function of the adrenals remains intact. Though rare, there have been case reports of patients developing SAI while taking megestrol. Megestrol acts as a progestin and is used for appetite stimulation in patients with cachexia. Megestrol is believed to have cross-affinity for glucocorticoid receptors which leads to suppression of the pituitary-adrenal axis. This suppression leads to decreased ACTH production, inducing SAI. In this case, the patient was receiving higher than prescribed doses of megestrol at home. When her dose was reduced on admission it precipitated her adrenal insufficiency, accounting for the worsening of her hyponatremia. Identification of SAI in patients taking megestrol is imperative as early recognition and diagnosis can prevent severe complications such as adrenal crisis. These patients should have megestrol discontinued and be placed on appropriate hydrocortisone therapy. Close follow-up is required as it can take 2-3 months for pituitary-adrenal axis recovery. Presentation: Saturday, June 17, 2023