RT Book, Section
A1 Williams, Saralyn R.
A1 Thurman, R. Jason
A2 Knoop, Kevin J.
A2 Stack, Lawrence B.
A2 Storrow, Alan B.
A2 Thurman, R. Jason
SR Print(0)
ID 1181056791
T1 Tricyclic Antidepressant Poisoning
T2 The Atlas of Emergency Medicine, 5e
YR 2021
FD 2021
PB McGraw-Hill
PP New York, NY
SN 9781260134940
LK accessemergencymedicine.mhmedical.com/content.aspx?aid=1181056791
RD 2024/04/19
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.