Cardiac Dysrhythmia Associated With Opioid Toxicity

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder involving abnormal motility. The patients are commonly started on symptom control management for IBS - diarrhea subtype by prescribing antimotility agents, usually having opioid agonist activity, and newer medications have been emerging for this as well. Patients sometimes self-medicate themselves to exceedingly high doses of these medications to achieve symptoms control. There are only a few cases of opioid-induced arrhythmia in the literature, primarily loperamide being used as a drug substitute by substance abusers. Still, it has been rarely reported to cause arrhythmia in a patient with IBS. We present a case of a 33-year-old female with a past medical history of hypertension and depression who presented to the emergency department for evaluation of syncope. She had wide complex tachycardia on electrocardiogram (EKG) with prolonged rate-corrected QT interval (QTc). Her medications, including eluxadoline, Lomotil, and loperamide, were held and she was discharged on mexiletine with normal QTc. She did not have any more incidences of arrhythmia. This case highlights the importance of not overdosing on opioid agonist medications prescribed to treat IBS as these can lead to potentially fatal complications. Physicians have to be judicious in promptly determining that the cause of arrhythmia can also be over-the-counter (OTC) medications.