ABSTRACT
Dothiepin is a tricyclic antidepressant which is widely prescribed in Australia. The drug is used for the treatment of both endogenous and reactive depressions and, in our hospital, some 27% of patients requiring antidepressant therapy are receiving dothiepin. It is therefore not surprising that dothiepin is now often encountered in overdose situations. Monitoring of plasma tricyclic antidepressant levels in both therapeutic and overdose cases is essential, as it has been well documented that high plasma drug levels can cause cardiac arrhythmias. The particular interest has been in evaluating the TDx assay for assessment of overdose cases, and in this regard the ease and speed with which results can be obtained is particularly helpful. The lower cross-reactivity of the antibodies used in the TDx assay should always be borne in mind when interpreting high tricyclic results such as those occurring after an overdose.
