Loperamide induced cardiac arrhythmia successfully supported with veno-arterial ECMO (VA-ECMO), molecular adsorbent recirculating system (MARS) and continuous renal replacement therapy (CRRT)

Risk of Cardiac Lesion with Chronic and Acute Use of Loperamide-An Integrative Review

Loperamide is a synthetic opioid commonly used as an antidiarrheal due to its activation of u-opioid receptors in the myenteric plexus. In therapeutic doses, it inhibits peristalsis and has anti-secretory and anti-motility effects, until metabolized by intestinal and hepatic CYP3A4 and CYP2C8 into inactive metabolites. Furthermore, loperamide also inhibits L-type voltage-gated calcium (Ca²⁺) channels, increases action potential duration, and can induce arrhythmias and even cardiotoxicity, particularly when taken in extremely high doses. Thus, the aim of this study was to perform an integrative review of the available evidence in the recent literature on the cardiac risks of acute and chronic use of loperamide. In electrocardiogram (ECG) analysis, the most common finding was QTc prolongation in 27 cases, followed by QRS prolongation, first-degree atrioventricular (AV) block, torsades de pointes, ventricular tachycardia, and right bundle branch block. As for the symptoms encountered, syncope, weakness, palpitations, lightheadedness, shortness of breath, nausea, vomiting, bradycardia, and cardiac arrest were the most common. Loperamide can inhibit hERG voltage-gated potassium (K⁺) channels (Kv11.1), leading to the prolongation of repolarization, QTc interval prolongation, and increased risk of torsades de pointes. In addition, loperamide can inhibit voltage-gated sodium (Na⁺) channels (Nav1.5), impairing electrical cardiac conduction and potentiating QRS interval widening. Therefore, QTc prolongation, torsades de pointes, and other ECG alterations are of particular concern regarding loperamide toxicity, particularly when overdosed.

Loperamide-induced ventricular tachycardia storm

Loperamide is an over-the-counter, peripherally-acting, μ-opioid receptor agonist commonly used in the treatment of diarrhoea. It has increasingly been recognised as a potential drug of misuse, having previously been thought to have low potential for abuse owing to its low bioavailability and poor penetration of the central nervous system. High doses can result in life-threatening cardiac-toxicity. We present a case of a young woman who had been self-treating her depression with high doses of loperamide for one year, who then presented to hospital with syncope secondary to ventricular tachycardia (VT). While in the emergency department (ED) the patient had monomorphic pulseless VT requiring electrical cardioversion multiple times. Transfer to a tertiary cardiac centre was immediately arranged after she was stabilised and intubated. This complicated the diagnostic process as a thorough history could not be obtained on arrival to the tertiary centre, which meant the loperamide misuse only came to light multiple days into admission, after the patient was extubated. The final diagnosis of loperamide-induced secondary long-QT syndrome was made and the patient made a full recovery.

A Case Report of Cardiogenic Syncope Due to Loperamide Abuse: Acute Presentation and Novel Use of Buprenorphine

Introduction

Loperamide is a non-prescription anti-diarrheal agent targeting μ-opioid receptors in the intestinal tract. At high doses it crosses the blood-brain barrier, where μ-opioid agonism can cause euphoric effects. Misuse has been increasing for both the euphoric effects and as an alternative treatment for opioid dependence and withdrawal.

Case Report

Here we report the case of a 30-year-old woman presenting with syncope, who was found to have severe myocardial conduction delays in the setting of chronic loperamide abuse.

Conclusion

Treatment with sodium bicarbonate and hypertonic sodium resulted in improvement of her conduction abnormalities. Prior to discharge she was initiated on buprenorphine for her opioid use disorder.

Misuse of medication in adult substance misuse services: a systematic review protocol

INTRODUCTION

There is a growing concern about the misuse of over the counter (OTC) and prescription only medication (POM) because of the impact on physical and mental health, drug interactions, overdoses and drug-related deaths. These medicines include opioid analgesics, anxiolytics such as pregabalin and diazepam and antidepressants. This protocol outlines how a systematic review will be undertaken (during June 2021), which aims to examine the literature on the pattern of OTC and POM misuse among adults who are accessing substance misuse treatment services. It will include the types of medication being taken, prevalence and demographic characteristics of people who access treatment services.

METHODS AND ANALYSIS

An electronic search will be conducted on the Cochrane, OVID Medline, Pubmed, Scopus and Web of Science databases as well as grey literature. Two independent reviewers will conduct the initial title and abstract screenings, using predetermined criteria for inclusion and exclusion. If selected for inclusion, full-text data extraction will be conducted using a pilot-tested data extraction form. A third reviewer will resolve disagreements if consensus cannot be reached. Quality and risk of bias assessment will be conducted for all included studies. A qualitative synthesis and summary of the data will be provided. If possible, a meta-analysis with heterogeneity calculation will be conducted; otherwise, Synthesis Without Meta-analysis will be undertaken for quantitative data. The reporting of this protocol follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

ETHICS AND DISSEMINATION

Ethical approval is not required. Findings will be peer reviewed, published and shared verbally, electronically and in print, with interested clinicians and policymakers.

PROSPERO REGISTRATION NUMBER

CRD42020135216.