Predicting severity of tricyclic antidepressant overdose

Area of Science:

• Clinical Toxicology
• Emergency Medicine
• Pharmacovigilance

Background:

• Tricyclic antidepressant (TCA) overdose is a significant cause of poisoning.
• Assessing TCA toxicity relies on various clinical and laboratory parameters.
• Predicting prognosis and safe discharge from intensive care unit (ICU) remains a challenge.

Purpose of the Study:

• To evaluate the prognostic value of plasma TCA concentration, QRS duration, and level of consciousness in TCA overdose.
• To determine criteria for safe patient discharge from the ICU following TCA overdose.

Main Methods:

• Retrospective analysis of 67 patients with TCA overdose across four centers.
• Assessment of plasma TCA levels, coma grade (Matthew-Lawson Coma Scale), and ECG parameters (QRS duration).
• Recording of complications including seizures, hypotension, arrhythmias, and need for mechanical ventilation.

Main Results:

• Coma grade was the most significant predictor of outcome in TCA overdose.
• Patients with a coma grade of II or less, admitted over 6 hours post-ingestion, had a low risk of serious complications.
• Plasma TCA concentration did not add prognostic value for predicting complications or guiding ICU discharge.
• An alert patient with QRS duration < 100 ms indicated safe transfer from ICU.

Conclusions:

• Level of consciousness and QRS duration are superior indicators of TCA toxicity compared to plasma concentration.
• An alert mental status and a QRS duration < 100 ms are reliable criteria for safe ICU discharge in TCA overdose patients.