Loperamide-Induced Torsades de Pointes

Loperamide, an over-the-counter antidiarrheal, works on the µ opioid receptor with minimal opioid activity if taken as directed. Recently, it has gained popularity as the "poor man's methadone" at supratherapeutic dosing. Opioid antagonism with naloxone is beneficial in reversing respiratory depression but has no effect on cardiotoxicity due to the human ether-a-go-go-related gene (hERG). We present the case of a 34-year-old female who presented for syncope after taking 48 tablets of 2 mg loperamide. On arrival, she was obtunded with variable heart block and a QTc of 560 ms. Subsequently, due to further QT prolongation from loperamide to 656 ms, she developed Torsades de Pointes requiring defibrillation at 120 J twice. Ultimately, she was discharged home with psychiatric and substance abuse outpatient follow-up. Patients and healthcare providers face new challenges with the increase in loperamide misuse due to easy access and delayed identification. It is important for clinicians to recognize and be familiar with loperamide overdose given the potential for multiorgan failure and increased mortality.