The TCADs are generally more toxic in overdose, and within the first 6 hours usually manifest severe toxicity in the form of seizures or other central nervous system problems.
The Fatality Index (FTI) ranks amitryptyline (a TCAD) and tranylcypromine as the two highest-ranking drugs with "unacceptable risks" of [greater than] 40 deaths per million prescriptions per year.
Here, the patient had actually been prescribed acetaminophen, fluoxetine [a serotonin-reuptake inhibitor (SSRI)], and imipramine (a TCAD).
The presence of both acetaminophen and imipramine would have been detected by immunoassay because acetaminophen falls into the therapeutic drug monitoring (TDM) class and imipramine falls into the TCAD class.
The combination of a TCAD and a neuroleptic drug overdose may result in an intravascular conduction delay and first degree atrioventricular block.