Catecholamine levels in tricyclic antidepressant self-poisoning.

In a consecutive series of 208 patients with tricyclic antidepressant self poisoni ng, urinary catec holami ne 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 noradrenaline excretion was elevated during the first 24 hours after tricyclic antidepressant self-poisoning, to! a level 2-3 times that found in the other overdose group, but was normal by the third day. Cardiac tach ya rr h yt hmias developed i n 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.