Acute myocarditis after massive phenelzine overdose

Monoamine oxidase inhibitors (MAOIs) are uncommonly used due to their high frequency of adverse effects, including tachycardia and hypertension. Recently, there has been renewed interest in the role of this class of drugs in treating a variety of psychiatric disorders. The clinical features of MAOI overdose are poorly characterised. This paper describes a novel cardiac complication of phenelzine toxicity in a previously healthy young adult with no history of cardiovascular disease.

A 23-year-old woman presented to hospital after massive phenelzine overdose, and the clinical features and pathological findings are discussed in light of existing literature.

Clinical features of phenelzine toxicity included reduced consciousness level, seizures, and tachycardia, in keeping with previous reports. Unexpectedly, the patient developed severe and unexplained hypotension and impaired left ventricular function, and died 3 days after initial presentation. Post-mortem examination confirmed high serum phenelzine concentrations (4.1 mg/L) and histopathological features that were consistent with drug-induced acute myocarditis.

Acute myocarditis was attributed to phenelzine in the absence of any plausible alternative explanation. This possible complication should be considered in patients who develop unexplained hypotension after phenelzine overdose.