Molecular Adsorbent Recirculating System Therapy in Severe Amlodipine Overdose: Two Cases and Review of the Literature

BackgroundCalcium channel blocker (CCB) overdose is a significant cause of cardiovascular drug overdose-related mortality, with amlodipine emerging as the most frequently implicated agent in serious intoxication. Current management strategies for CCB poisoning include vasopressors, high-dose insulin therapy, and other adjunctive treatments. The unique pharmacodynamic profile of amlodipine can lead to severe and persistent vasoplegic shock that is refractory to conventional therapy. The Molecular Adsorbent Recirculating System (MARS), an albumin dialysis technique capable of removing protein-bound toxins, has been proposed as a potential adjunctive therapy in cases of refractory vasodilatory shock associated with severe amlodipine poisoning.MethodsWe report two cases of severe amlodipine poisoning complicated by refractory vasodilatory shock treated with the Molecular Adsorbent Recirculating System (MARS). A targeted PubMed search was also performed to identify published reports of calcium channel blocker intoxication with severe shock treated with MARS. Only reports describing amlodipine ingestion, either alone or with co-ingested agents, were included.ResultsBoth cases involved severe amlodipine poisoning complicated by refractory vasodilatory shock with multiorgan dysfunction requiring multiple vasopressors, high-dose insulin therapy, mechanical ventilation, and renal replacement therapy. Initiation of MARS was temporally associated with progressive hemodynamic stabilization, including reductions in vasopressor requirements and improvement in lactate levels. In the first case, MARS was successfully continued during prone ventilation for severe acute respiratory distress syndrome. In the second case, persistent cardiopulmonary failure required extracorporeal membrane oxygenation (ECMO). Reinitiation of MARS during ECMO support was associated with improved lactate clearance and reduced vasopressor requirements.ConclusionsSevere amlodipine poisoning can result in profound and persistent vasodilatory shock with multiorgan dysfunction despite multiple conventional and adjunctive therapies. MARS may represent a useful adjunctive therapy in selected cases and can be integrated into complex critical care strategies, including prone ventilation and extracorporeal membrane oxygenation.