Abstract Introduction: The opioid epidemic is a public health crisis and clinicians should be aware of the many under-recognized endocrinopathies associated with opioids. Herein, we present a case that exemplifies the endocrine-related adverse effects of methadone therapy. Clinical Case: A 43-year-old Caucasian female with chronic back pain with opioid dependence, high dose methadone use (195 mg daily), and diabetes presented with refractory hypoglycemia. She was diagnosed with ketone prone diabetes eight months prior. She had since been weaned off insulin and her most recent HbA1c was 4.2%. During this time, she had an intentional weight loss of 60 pounds. On examination, she had bilateral lower extremity pitting edema with scaly plaques on the extremities. Laboratory tests showed C-peptide of 0.8 (0.9–7.1 ng/mL), insulin level of < 2 (3–25 mcIntUnits/mL), proinsulin of 4.6 (<18.8 pMol/L) with concurrent glucose of 48 mg/dl. She failed the ACTH stimulation test with 60 minute cortisol of 16.8 mcg/dL and was started on prednisone for adrenal insufficiency (AI). The pituitary and adrenal were normal on imaging. Her albumin was 1.5 (3.7–5.5 gm/dL) and she had vitamin and micronutrient deficiencies including copper, zinc, thiamine, selenium, and vitamin A. The insulin antibody test, paraneoplastic panel, celiac panel, A1 antitrypsin test, EGD, and colonoscopy were all non-revealing. A liver biopsy showed glycogenic hepatopathy. She improved clinically after prednisone initiation and treatment of malnutrition. The hypoglycemia improved but did not resolve as she refused to reduce methadone dose. Discussion: The proposed mechanism of opioid-induced AI is the inhibitory effect on the hypothalamic-pituitary-adrenal axis, similar to the effect on the gonadal axis which causes hypogonadism. The risk for hypoglycemia is increased in patients taking more than 40 mg of oral methadone per day, and although the mechanism remains unclear, it is independent of adrenal function. Our patient had adrenal insufficiency and hypoglycemia related to methadone, which was further complicated by malnutrition. The glycogenic hepatopathy is a benign reversible condition that is believed to be a consequence of fluctuation in glucose levels. Conclusion: Given the life-threatening nature of adrenal crisis and the overlap in symptomatology with opiate overdose, clinicians should be prompt in evaluating for endocrinopathies in patients on chronic high dose opiates, and patients should be appropriately counseled on the potential consequences of methadone use.