Methylene blue in the management of severe distributive shock in calcium channel blocker overdose

Abstract

Introduction: Deliberate polypharmacy overdose is associated with an increasing proportion of admissions to the intensive care unit. Overdose on hemodynamic active substances such as calcium channel blockers can be fatal as it is associated with severe distributive shock. Methylene blue has drawn attention in critical care medicine for its use in the management of distributive shock, particularly in cases of anaphylaxis, septic shock, and shock following cardiac bypass surgery. We describe the use of methylene blue in the management of refractory shock due to calcium channel blocker (CCB) overdose. Case Report: We present a case of benzothiazepine type CCB overdose which leads to admission to the intensive care unit for the management of severe distributive shock. Conventional treatments including vasopressors and high dose insulin therapy were instituted, but despite these treatments the patient remained hypotensive. The decision was made to administer methylene blue following which the patient achieved hemodynamic stability and was successfully weaned off all vasopressors. Conclusion: This case report specifically focuses on the use of methylene blue in distributive shock secondary to CCB overdose. Currently there are no randomized control trials to support its use, and evidence is limited to observational studies including single case reports. In this case report we describe the mechanism of action of methylene blue and why we believe it makes for the perfect adjunct therapy in calcium channel blocker overdose.