A 29-year-old female with history of heroin abuse and depression presented after being found altered and confused. At the time, the patient was known to be taking an estimated 300 tablets of loperamide daily for “chronic stomach issues” (1 tablet is 2 mg for an approximate total of 600 mg). Her husband reported that within the past year, he would witness her taking at least one entire bottle of loperamide with roughly 96 tablets up to 3 times per day. There were no other medications reported, including use of any antidepressants.\nOn presentation, she was tachycardic to 156 BPM (beats per minute) and hypotensive to 70/40 mm Hg. Initial electrocardiogram (ECG) showed polymorphic VT with prolonged QTc of 669 ms ( and ). Subsequently, she developed recurrent episodes of VT that degenerated into torsades de pointes, resulting in multiple cardioversions and her admission to the cardiac intensive care unit.\nPreliminary laboratory findings were unremarkable except for the following: leukocytosis 18 bil/L, anion gap 16, and lactate 2.2 mmol/L. Chemistries showed a sodium 136 mmol/L, potassium 4.3 mmol/L, calcium 2.2 mmol/L, and magnesium 1.6 mmol/L. Urine drug screen was positive for cannabinoids, and her chest X-ray was normal. A serum loperamide level was ordered but would not result until after her discharge.\nAfter cardioversion in the emergency room, the patient was stabilized. Repeat ECG shortly after demonstrated a QTc of 515 ms. Poison control was contacted immediately and recommended supportive management. Unfortunately that evening, she began having frequent episodes of nonsustained VT triggered by positional change and vomiting (). Additional intravenous magnesium sulfate was given but symptoms persisted. A sodium bicarbonate infusion at 150 mEq/h was initiated per the recommendations of the electrophysiologist on call.\nSeveral hours later, the patient further decompensated into sustained VT. Electrical cardioversion with 120 J was required to maintain hemodynamic stability. Given her tenuous status and recurrent VT storm, she was intubated and sedated to suppress sympathetic overstimulation. Subsequently, an isoproterenol infusion was started at 2 µg/min to reduce the number of subsequent VT episodes.\nAfter 8 hours without VT, isoproterenol was reduced to 1 µg/min and the bicarbonate infusion was discontinued. Her transthoracic echocardiogram was completed and shown to be normal. Isoproterenol was stopped on day 3, and the patient was extubated. By then, she was free of VT for more than 24 hours and her QTc improved to 500 ms. No additional anti-arrhythmics were started, and the patient was downgraded and later discharged from the hospital ().\nThe final results of her serum loperamide and desmethyl loperamide (the primary metabolite of loperamide) were elevated to 26 ng/mL (normal is <10 ng/mL) and 160 ng/dL (normal is <20 ng/dL), respectively.
A 38-year-old female with an extensive history of poly-substance abuse presented after an outside hospital cardiac arrest that was recognized in the field to be caused by ventricular fibrillation of uncertain duration in the field. Her family reported daily use of two boxes of loperamide (144 tabs, 288 mg) daily for an indefinite period of time for the purpose of controlling symptoms of heroin withdrawal. She formerly used codeine and suboxone for opioid withdrawal symptom control but no longer had access to those treatments. Other than the polysubstance abuse, she was not known to have any known chronic medical illness and was not taking any prescription medications. There was no family history of cardiac arrhythmias or sudden cardiac death (SCD). The patient was successfully resuscitated in the field as per ACLS protocol with defibrillation, and, for airway protection, was intubated. She was initially taken to an outside facility and then emergently transferred to a tertiary care center. Hypothermia protocol was not initiated because of non-availability at the outside hospital. At the time of arrival, electrocardiogram (EKG) revealed a wide complex undetermined atrial rhythm at a rate of 58 bpm with prolonged QT and QTc intervals (). The patient had no available baseline EKG for comparison. Emergent coronary angiography indicated normal coronary arteries. Urine toxicology screen was negative. The regional poison control center was notified and recommended sodium bicarbonate and lipid infusions. Electrolytes, including potassium, magnesium, and calcium, were maintained within normal limits through intravenous supplementation.\nDue to bradycardia, the patient was started on an isoproterenol drip. The following day, her telemetry alarmed for a very wide QRS; EKG showed wide complex tachycardia () that culminated with a ventricular cardiac arrest. She was successfully resuscitated as per ACLS protocol with amiodarone push and lidocaine infusion. Six hours later, she developed sustained polymorphic ventricular tachycardia without loss of pulse that responded to magnesium supplementation. A temporary transvenous pacer was inserted with overdrive strategy. She was reliably paced as shown in the EKG (). Shortly after that, however, she developed a third ventricular fibrillation cardiac arrest that was successfully resuscitated as per ACLS protocol with multiple shocks (>10 times). Higher electrolytes levels were targeted with a potassium goal of 4.5 mmol/L and magnesium goal of 2–2.5 mg/dL. It was expected that the loperamide side effect would last for 24–48 hours. On Day 3, she was extubated without any residual neurologic deficit. She remained bradycardic when the pacemaker was turned down (EKG, ). Isoproterenol was weaned. On Day 5, she developed another episode of ventricular fibrillation that responded to four shocks of 200 Joules. Isoproterenol infusion was restarted transiently due to bradycardia. She was discharged to the medical floor on Day 6. However, on Day 11, she had multiple episodes of Torsade de Pointes (TdP), that were self-limiting and without symptoms. She was readmitted to the ICU due to these episodes, and temporizing measures were restarted (lidocaine and isoproterenol) with positive results. The patient threatened to leave the ICU against medical advice, so AICD/DDD ICD was placed to prevent ventricular fibrillation cardiac arrest given her recurring TdP. Repeat EKG () showed progressive shortening of the QTc and QT intervals. The patient changed her mind about leaving the ICU after the AICD placement and was discharged after medical stabilization two days later. She followed as outpatient with the EP team. She denied any symptoms or any further use of loperamide. Office EKG showed normal sinus rhythm at a rate of 85 bpm with normal QTc at 437 msec. Device interrogation demonstrated normal sensing and pacing pacemaker. She was enrolled in remote device monitoring every three months and has had no detected device shocks.