Tricyclic antidepressant plasma levels and adverse effects after overdose

Abstract

Forty patients ingesting tricyclic antidepressant (TAD) overdoses were studied as a pharmacologic model to determine whether total tricyclic antidepressant plasma levels correlated with major adverse effects and electrocardiographic findings. Maximum TAD plasma levels were higher in patients who died (p < 0.025) or had cardiac arrest (p < 0.02), needed respiratory support (p < 0.005), were unconscious (p < 0.02), had grand mal seizures (p < 0.001), ventricular rate ≥ 120/min (p < 0.01), cardiac arrhythmia (p < 0.05), QRS duration ≥ 100 msec (p < 0.00l), or bundle branch block (p < 0.05). TAD plasma levels correlated with the dose ingested by history (N = 29, r = 0.58, p < 0.001). Measurement of total TAD (free and protein-bound) appears to correlate well with biologic response.