Catecholamine Levels in Tricyclic Antidepressant Self-Poisoning

Summary: In a consecutive series of 20, patients with tricyclic antidepressant self-poisoning, urinary catecholamine excretion was measured, and the catecholamine level compared with that in ten patients having taken an overdose of other drugs. In both patient groups the electrocardiograph was monitored continuously for a minimum of 48 hours to detect cardiac arrhythmias. Urinary nor-adrenaline excretion was elevated during the first 24 hours after tricyclic anti-depressant self-poisoning, to a level 2–3 times that found in the other overdose group, but was normal by the third day. Cardiac tachyarrhythmias developed in four of the patients with antidepressant overdosage. The findings support the concept that sympathetic nervous system overactivity underlies the cardiac tachyarrhythmias which commonly accompany self-poisoning with this class of drugs.