Successful use of methylene blue in a pediatric case of refractory metformin-associated lactic acidosis

Metformin-associated lactic acidosis (MALA) is a rare but life-threatening complication of metformin toxicity, characterized by profound metabolic acidosis and vasoplegic shock.Although conventional therapies, such as bicarbonate administration and renal replacement therapy, are commonly implemented, certain cases may remain refractory and especially challenging.We report the case of a 17-year-old female who presented to the emergency department approximately 10 hours after a deliberate overdose of metformin and ibuprofen in a suicide attempt.Upon arrival, she exhibited severe lactic acidosis (pH 6.93; lactate 29 mmol/L) and rapidly progressed to refractory vasoplegic shock.Despite aggressive resuscitative measures, including intravenous fluids, high-dose vasopressors, and continuous renal replacement therapy, her condition continued to deteriorate.Methylene blue was administered as a rescue intervention, resulting in improved hemodynamic stability and correction of lactic acidosis, and ultimately a successful clinical outcome.The patient recovered fully and was discharged without any long-term sequelae.