Severe loperamide toxicity associated with the use of cimetidine to potentiate the “high”

While in the emergency department, the patient's mental status declined, she developed recurrent episodes of polymorphic and monomorphic ventricular tachycardia and was intubated and treated with lidocaine, sodium bicarbonate and repeated electrical cardioversion. [...]only a small amount of loperamide reaches the systemic circulation in therapeutic doses. Unfortunately, no serum loperamide or cimetidine concentrations were obtained, and the timing and dose ingested was not disclosed by the patient. [...]definitive causation is unable to be determined. Infrequent reports of cardiac conduction abnormalities and hypotension associated with cimetidine administration have been described, but only with rapid intravenous administration [38,39].4 Conclusion Health care providers should be aware of the growing public health threat of loperamide abuse and its associated life-threatening cardiotoxicity.