Intoxications with the monoamine oxidase inhibitor tranylcypromine: an analysis of fatal and non-fatal events.

Tranylcypromine (TCP) is a non-selective and irreversible monoamine oxidase inhibitor and an effective agent in the treatment of major depression. It features a complex pharmacologic profile and overdoses might induce severe intoxications. To identify typical clinical presentations of TCP-intoxications, range of associated TCP-dosages and possible differences between fatal and non-fatal intoxications a systematic review of all previously published cases of TCP-intoxications was conducted. We detected n=20 reports of TCP-intoxications in the literature (fatalities n=10). Mean age was 36.7 years (median 37); the majority of patients were female (60%). Frequent findings in patients with TCP-intoxications were disturbance of consciousness/cognitive dysfunction (90%), cardio-vascular symptoms (55%), hyperthermia (50%), respiratory distress (45%), delirium (45%), muscular rigidity (30%) and renal failure (20%). Suicidal intent was present in n=18 (90%) patients. First clinical symptoms related to TCP-intoxication developed on average in less than 1 day. The average dosage related to TCP-intoxication was 677 mg. The highest survived TCP-dosage was 4000 mg and the lowest fatal dosage was 170 mg. Patients with fatal intoxications were on average older (40.5 vs. 32.8 years) and developed a more rapid onset of symptoms (0.2 vs. 0.8 days). Death occurred after a mean time of 0.6 days; symptom relief in patients with non-fatal intoxications developed on average after 3.2 days. Considering the large dose spectrum between survived and lethal TCP-dosages individual susceptibility factors might play a role regarding the severity of clinical symptoms independently of the ingested dosage.