Cardiac arrest due to trimethoprim-sulfamethoxazole induced hyperkalemia – a case report

Abstract

Abstract Background: Prescribing physicians must be aware of drug-drug interactions and exercise caution to prevent life-threatening electrolyte abnormalities. Here, we present a case of hyperkalemia-induced cardiac arrest in a patient treated with lisinopril with underlying chronic kidney disease and a recent course trimethoprim-sulfamethoxazole. We emphasize the need for awareness and vigilance when reconciling medications to thwart life-threatening consequences of even seemingly benign drug interactions. Case presentation: A 55-year-old male was brought to the emergency room after being found unresponsive and pulseless for an unknown period due to cardiac arrest. Resuscitative efforts were successful in achieving return of spontaneous circulation after 15 minutes. In the emergency department, he was found to have a potassium level of 6.9. Further history obtained from the medical proxy revealed that the patient recently completed a course of trimethoprim-sulfamethoxazole, and he had underlying past medical history of chronic kidney disease and hypertension requiring treatment with lisinopril. The patient was subsequently transferred to the intensive care unit for neuroprognostication after arrest, continuous renal replacement therapy, and pressor support. Workup to investigate other causes of his arrest was unremarkable, leaving drug-induced hyperkalemia as the leading diagnosis made by exclusion. Conclusions: We underscore the need to recognize drug interactions when prescribing new medications and the potential complications they may have in patients with particular risk factors. In this case, our patient had underlying chronic kidney disease and hypertension requiring management with lisinopril. The addition of TMP-SMX precipitated life-threatening hyperkalemia which caused his cardiac arrest. We underscore the importance of preventing dangerous arrhythmias through detailed medication reconciliations and diligence when prescribing new medications to prevent adverse interactions.