GREATER TOXICITY IN OVERDOSE OF DOTHIEPIN THAN OF OTHER TRICYCLIC ANTIDEPRESSANTS

Epidemiological studies have implicated dothiepin in a greater number of self-poisoning deaths than would be expected from its use. We have prospectively assessed the clinical toxicity of dothiepin and other tr icyclic antidepressants (TCAs) in overdose. We followed-up consecutive ly admitted patients with TCA poisoning managed by our department betw een January, 1987, and August, 1992. 75 patients had taken dothiepin, 101 amitriptyline, 83 doxepin, and 61 other TCAs. Death after TCA pois oning is rare nowadays, so we used intermediate outcome measures-gener al seizures, tachyarrhythmias, sedation, and QRS width on the electroc ardiogram. 15 patients had seizures and 7 tachyarrhythmias. When we ex cluded patients who had taken more than one TCA, general seizures were more likely after dothiepin than after other TCAs (9/67 vs 5/220) as were arrhythmias (4/67 vs 3/220). Rates of other complications were si milar. The dothiepin group had ingested a larger dose, attributable to the larger average tablet strength, than patients who took other TCAs . The odds ratio for seizures with dothiepin versus other TCAs was 6.7 (95% Cl 2.2-20.7) unadjusted and 7.1 (2.2-23.2) after adjustment for sex, age, and ingested dose. The corresponding odds ratios for arrhyth mias were 4.6 (1.0-21.1) and 3.4 (0.7-16.3). Dothiepin in overdose see ms to be proconvulsant. Patients with only minor sedation and normal l imb-lead QRS width may still have major complications. Consideration s hould be given to the use of other antidepressants in patients at risk of seizures or suicide. Regulatory authorities should review the need for a 75 mg strength tablet of any TCA.