TY - CHAP M1 - Book, Section TI - Tricyclic Antidepressant Poisoning A1 - Williams, Saralyn R. A1 - Thurman, R. Jason A2 - Knoop, Kevin J. A2 - Stack, Lawrence B. A2 - Storrow, Alan B. A2 - Thurman, R. Jason Y1 - 2021 N1 - T2 - The Atlas of Emergency Medicine, 5e AB - Tricyclic antidepressants (TCAs) are being used more frequently for a wide variety of clinical indications, and toxicity remains a significant cause of poisoning morbidity and mortality. TCA toxicity is related to pharmacologic effects on the myocardium, CNS, and vasculature. M1-muscarinic receptor blockade may result in an anticholinergic toxidrome. CNS toxicity may range from sedation to coma. Seizures, agitation, and delirium may occur. Inhibition of voltage-gated sodium channels results in characteristic widening of the QRS complex. A limb-lead QRS duration greater than 120 ms is associated with an increased incidence of seizures, whereas a limb-lead QRS duration greater than 160 ms is associated with an increased incidence of ventricular dysrhythmias. Similarly, in adults, a terminal R wave in lead aVR greater than or equal to 3 mm is associated with increased risk of seizure or dysrhythmias. SN - PB - McGraw-Hill CY - New York, NY Y2 - 2024/03/28 UR - accessemergencymedicine.mhmedical.com/content.aspx?aid=1181056791 ER -