Opioid-Induced Adrenal Insufficiency

A woman in her 40s with opioid use disorder receiving methadone (70 mg daily) was admitted for extended antibiotic treatment for methicillin-resistant Staphylococcus aureus bacteremia. She had been taking methadone at varying doses (ranging from 15 to 70 mg daily) for 15 years.

Following the resolution of bacteremia, she experienced unexplained persistent hyponatremia (129 mEq/L) and dizziness, with her urine sodium levels exceeding 40 mEq/L. A high dose, 250-μg cosyntropin stimulation test was performed, which revealed her cortisol levels were 6.6, 17.2, and 19.2 μg/mL (to convert to nmol/L, multiply by 27.6) at baseline, 30 minutes, and 60 minutes, respectively. A serum adrenocorticotropic hormone (ACTH) level was not measured.