Loperamide-Related Deaths in North Carolina

Loperamide (Imodium®) has been accepted as a safe, effective, over-the-counter anti-diarrheal drug with low potential for abuse. It is a synthetic opioid that lacks central nervous system activity at prescribed doses, rendering it ineffective for abuse. Since 2012, however, the North Carolina Office of the Chief Medical Examiner has seen cases involving loperamide at supratherapeutic levels that indicate abuse. The recommended dose associated with loperamide should not exceed 16 mg per day, although users seeking an opioid-like high reportedly take it in excess of 100 mg per dose. When taken as directed, the laboratory organic base extraction screening method with gas chromatography-mass spectrometry/nitrogen phosphorus detector lacks the sensitivity to detect loperamide. When taken in excess, the screening method identifies loperamide followed by a separate technique to confirm and quantify the drug by liquid chromatography-tandem mass spectrometry. Of the 21 cases involving loperamide, the pathologist implicated the drug as either additive or primary to the cause of death in 19 cases. The mean and median peripheral blood concentrations for the drug overdose cases were 0.27 and 0.23 mg/L, respectively. Furthermore, an extensive review of the pharmacology associated with loperamide and its interaction with P-glycoprotein will be examined as it relates to the mechanism of toxicity.