Naltrexone-Associated Non-ST-Elevated Myocardial Infarction

Medications for opioid use disorder (MOUD) and opioid agonist therapy (OAT) are the mainstays of treatment in opioid use disorder. Significant caution is encouraged upon initiation to reduce the precipitation of opioid withdrawal. Cardiac events in the setting of opioid withdrawal are rare and incompletely understood. A 46-year-old woman with a history of opioid-use disorder, hypertension, hyperlipidemia, diabetes, tobacco-use disorder, and rheumatoid arthritis presented with nausea, vomiting, and lightheadedness after taking naltrexone following buprenorphine. She was found to be hypertensive and tachycardic in the emergency department, with a troponin of 0.38 ng/mL (reference: 0.00-0.30 ng/mL) and an electrocardiogram (ECG) without ST or T-wave changes. She was admitted for a non-ST-elevation myocardial infarction (NSTEMI) and hypertensive emergency in the setting of opioid withdrawal. Her blood pressure was controlled, and she received full-dose aspirin and high intensity atorvastatin. Afterwards she was started on a modified OAT regimen of buprenorphine 8 mg daily. Her cardiac enzymes down-trended and her condition became stable after which she was discharged home. Cardiac events are an uncommon yet lethal occurrence in opioid withdrawal. The likely etiology of NSTEMI in our patient was demand ischemia induced by opioid withdrawal, augmented by her various other cardiac risk factors. Practitioners should be aware of these possible adverse events, especially in those with preexisting cardiac disease. Meticulous efforts should be made to instruct patients as to the proper dosing schedule when initiating opioid therapy, and when initiating MOUD/OAT in order to prevent poor outcomes.