Hemodynamic improvement using methylene blue after calcium channel blocker overdose

Abstract

Calcium channel blocker overdoses are often fatal despite standard treatment. Methylene blue is a novel adjunct that should be considered in refractory cases. Currently accepted therapeutic modalities include intravenous fl uids, calcium, vasopressors and high-dose insulin euglycemic therapy, however shock may persist despite these treatment options. ethylene blue has been utilized in sepsis, shock after cardiac surgery and other non-poisoning causes of shock. However, there are only ten human case reports and one animal study regarding its utility. The case reports describe its use in shock caused by quetiapine, valsartan and dihydropyridine calcium channel blockers, and measure the outcomes of hemodynamics and mortality. The animal study used a rat-model with thirty subjects treated with a lethal dose of amlodipine, followed by methylene blue or normal saline. Results revealed an increase in heart rate, mean arterial pressure (MAP) and median survival time in those treated with methylene blue. x pe r t c o n s e n s u s r e c o m m e n d a t i o n s f o r t h e management of calcium channel blocker poisoning in adults were recently assembled and did not recommend the use of methylene blue as first-line treatment, given that the experience was limited to a small number of case reports. However, with additional case reports attesting to its effi cacy, there may be a role for methylene blue in the treatment of drug-induced vasodilatory shock.