Cardiotoxicity and serotonin syndrome complicating a milnacipran overdose

Milnacipran is a selective serotonin and norepinephrine reuptake inhibitor, recently approved for use in the USA for treatment of fibromyalgia. This case report describes a 59-year-old woman who ingested 3,000 mg of milnacipran in a suicide attempt. Following the ingestion, she became obtunded and developed autonomic instability. She required mechanical ventilation, treatment for hypertension, and then ultimately vasopressor support for refractory hypotension. In addition, she developed a transient, acute cardiac dysfunction with global hypokinesis and an ejection fraction of 30%. Resolution of the cardiac dysfunction was documented on repeat echocardiogram 2 days after the initial study. This was confirmed by cardiac catheterization performed 4 days after the acute ingestion in which coronary arteriogram was normal and left ventricular ejection fraction was 70%. Acute overdose was confirmed by quantification of plasma milnacipran concentration of 8,400 ng/mL obtained 5 h post-ingestion. To our knowledge, this represents the first case of cardiac toxicity complicating a milnacipran overdose in the medical literature.