Electrocardiographic changes in loperamide toxicity: Case report and review of literature

Abstract

Introduction Loperamide, an antidiarrheal agent, is a µ‐opioid receptor agonist increasingly abused to prevent opioid withdrawal or to produce euphoric effects. At supra‐therapeutic doses, loperamide can cause cardiac toxicity due to blockade of Na and IKr channels, resulting in wide QRS rhythms, severe bradycardia, prolonged QTc, polymorphic ventricular tachycardia, cardiac arrest, and death. There are limited data on the cardiotoxic effects of high dose loperamide. Methods and Results A case report of loperamide toxicity is presented and then added to a contemporary review of the literature. In total, the presentation and management of 36 cases of loperamide cardiotoxicity are summarized. The overall median daily dose (interquartile range) of loperamide was 200 (134‐400) mg. The median QRS duration was 160 (125‐170) ms. The median QTc duration was 620 (565‐701) ms. Ventricular tachycardia was experienced by 24/36 (67%) of patients, 20 of which were specified to be polymorphic. Treatment was supportive, providing advanced cardiopulmonary life support and aggressive electrolyte repletion. Isoproterenol infusion or overdrive pacing was employed in 19/36 (53%) of cases. The median time to electrocardiogram normalization or hospital discharge, whichever came first, was 5 (3.5‐10) days. Conclusion Loperamide overdose is a toxidrome that remains underrecognized, and in patients with unexplained cardiac arrhythmias, loperamide toxicity should be suspected. Prompt recognition is critical due to the delayed recovery and high risk for life‐threatening arrhythmias.

A Case Report of Loperamide-Induced Ventricular Storm

“…Unlike other µ-receptor agonists, loperamide has less CNS activity. 3 When it was first developed, loperamide was listed as a schedule II medication. By 1988, loperamide was marketed as a nonprescription medication because of its low abuse potential relative to other medications within its class.…”

“…Multiple conduction abnormalities have been reported, including prolonged QTc, VT/VF, torsades de pointes, and even sudden cardiac death. 3,7 Since loperamide’s approval in 1976, 48 cases of serious cardiac complications have been reported to the FDA. Of these 48, 10 patients died and 31 were hospitalized.…”

Cardiac Arrhythmia Secondary to Loperamide Abuse and Toxicity

“…It can also, when ingested in very excessive doses, cause cardiotoxicity. Most commonly reported cardiac manifestations are prolonged QT interval and ventricular tachyarrhythmias [5].…”

“…It pumps potassium out of the cardiac cell and plays an important role in repolarization of action potential. Loss of function of this channel is associated with hereditary long QT syndrome [5].…”

A tale of twists: loperamide-induced torsades de pointes and ventricular tachycardia storm

“…Our case consumed 200 mg/day for 7 days and also had TdP in addition to VT storm. A recent review on the electrocardiographic changes in loperamide toxicity was done by Teigeler et al 5. The review had 36 cases with median dose of loperamide 200 mg (134–400 mg), median QTc interval 620 ms (565–701 ms) and VT was experienced by 24/36 (67%) of patients.…”