Tricyclic antidepressant toxicity: Difference between revisions
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==Treatment==
==Treatment==
#GI Decontamination
===GI Decontamination===
##Gastric lavage if <1hr after ingestion
#Gastric lavage if <1hr after ingestion
##Activated charcoal 1gm/kg x1
#Activated charcoal 1gm/kg x1
#Cardiac Toxicity
===Cardiac Toxicity===
##Sodium Bicarbonate
====Sodium Bicarbonate====
###Indications:
#Indications:
####QRS >100ms, terminal RAD >120deg, Brugada pattern, ventricular dysrhythmias
##QRS >100ms, terminal RAD >120 deg, Brugada pattern, ventricular dysrhythmias
###Dosing
#Initial Dosing:
####Give 1-2 mEq/kg as rapid IVP; may repeat as necessary (stop if pH > 7.55)
#Give 1-2 mEq/kg as rapid IVP; may repeat as necessary (stop if pH > 7.55)
#####May give as 2-3 vials or prefilled syringes (50mL each) of 8.4% NaHCO3
#May give as 2-3 vials or prefilled syringes (50mL each) of 8.4% NaHCO3
####If effective, start infusion
#Infusion Dosing
#####Mix 125-150 mEq of NaHCO3 in 1L of D5W; infuse at 250 mL/hr
##Mix 125-150 mEq of NaHCO3 in 1L of D5W; infuse at 250 mL/hr
###Goal
#Treatment Goal:
####QRS <100ms
#QRS <100ms
####pH 7.50-7.55
#pH 7.50-7.55
###Monitoring
#Treatment Monitoring
####Monitor for volume overload, hypokalemia, hypernatremia, metabolic alkalosis
##Monitor for volume overload, hypokalemia, hypernatremia, metabolic alkalosis
##Hyperventilation
 
###Consider in pts unable to tolerate NaHCO3 (renal failure, pulm/cerebral edema)  
====Hyperventilation====
##Lidocaine
*Consider in patients unable to tolerate NaHCO<sub>3</sub> (renal failure, pulm/cerebral edema)  
###Consider for ventricular dysrhythmias if NaHCO3 alone is ineffective
 
##Phenytoin
====Lidocaine====
###Consider for ventricular dysrhythmias resistant to NaHCO3 and lidocaine
*Consider for ventricular dysrhythmias if NaHCO<sub>3</sub> alone is ineffective
##Synchronized cardioversion
;NOTE: avoid IA, IB, IC antiarrhythmics, Beta-Blockers, and Calcium Channel Blockers
###Appropriate in pts w/ persistent unstable tachydysrhythmias
 
##Avoid IA, IB, IC, BBs, and CCBs
====Phenytoin====
#Seizures
*Consider for ventricular dysrhythmias resistant to NaHCO<sub>3</sub> and lidocaine
##Benzodiazapines are 1st line
 
##Barbitutate are 2nd line
====Synchronized cardioversion====
##Phenytoin is ineffective
*Appropriate in pts w/ persistent unstable tachydysrhythmias
#Hypotension
 
##IVF 10mL/kg; pulmonary edema can develop if excessive fluids given
===Seizures===
##Give NaHCO3 if fluids ineffective (regardless of QRS duration)
#Benzodiazapines are 1st line
##Give norepi if fluids/NaHCO3 ineffective
#Barbitutate are 2nd line
###Start 1mcg/min; tirate up to 30mcg/min
 
#Dialysis not useful
===Hypotension===
*After repeat fluid boluses and with sodium load from NaHCO<sub>3</sub> norepinepherine should be the first line vasopressor
 
===Dialysis===
Not useful


==Disposition==
==Disposition==

Revision as of 21:18, 17 April 2014

Background

  1. Serious toxicity is almost always seen within 6hr of ingestion
  2. Ingestion amount:
    1. <1mg/kg: Nontoxic
    2. >10mg/kg: Life-threatening
    3. >1gm: Commonly fatal
  3. Coingestants often increase severity of toxicity

Clinical Features

  1. Na Channel Blockade
    1. Negative inotropy, heart block, hypotension, ectopy
  2. Anti-Histamine Effects
    1. Sedation, coma
  3. Anti-Muscarinic Effects
    1. Central
      1. Agitation, delirium, confusion, hallucinations
      2. Slurred speech, ataxia
      3. Sedation, coma
      4. Seizures
    2. Peripheral
      1. Mydriasis, decreased secretions, dry skin, ileus, urinary retention
      2. Tachycardia, hyperthermia
  4. Alpha1 Receptor Blockade
    1. Sedation, orthostatic hypotension, miosis
  5. Inhibition of amine reuptake
    1. Sympathomimetic effects
    2. Myoclonus, hyperreflexia
    3. Serotonin Syndrome (only when used in combination w/ other serotonergic agents)

Diagnosis

  1. Serious toxicity
    1. Conduction delays, SVT, V-tach, hypotension
    2. Respiratory depression
    3. Seizures
    4. Pulmonary Edema
  2. ECG
    1. Sinus Tachycardia (most frequent dysrhythmia)
    2. PR, QRS, QT Prolongation
    3. Right axis deviation (of terminal 40ms)
      1. Terminal R wave in aVR, S wave in I/aVL
    4. Brugada pattern (15%)

TCA Toxicity.jpg

Treatment

GI Decontamination

  1. Gastric lavage if <1hr after ingestion
  2. Activated charcoal 1gm/kg x1

Cardiac Toxicity

Sodium Bicarbonate

  1. Indications:
    1. QRS >100ms, terminal RAD >120 deg, Brugada pattern, ventricular dysrhythmias
  2. Initial Dosing:
  3. Give 1-2 mEq/kg as rapid IVP; may repeat as necessary (stop if pH > 7.55)
  4. May give as 2-3 vials or prefilled syringes (50mL each) of 8.4% NaHCO3
  5. Infusion Dosing
    1. Mix 125-150 mEq of NaHCO3 in 1L of D5W; infuse at 250 mL/hr
  6. Treatment Goal:
  7. QRS <100ms
  8. pH 7.50-7.55
  9. Treatment Monitoring
    1. Monitor for volume overload, hypokalemia, hypernatremia, metabolic alkalosis

Hyperventilation

  • Consider in patients unable to tolerate NaHCO3 (renal failure, pulm/cerebral edema)

Lidocaine

  • Consider for ventricular dysrhythmias if NaHCO3 alone is ineffective
NOTE
avoid IA, IB, IC antiarrhythmics, Beta-Blockers, and Calcium Channel Blockers

Phenytoin

  • Consider for ventricular dysrhythmias resistant to NaHCO3 and lidocaine

Synchronized cardioversion

  • Appropriate in pts w/ persistent unstable tachydysrhythmias

Seizures

  1. Benzodiazapines are 1st line
  2. Barbitutate are 2nd line

Hypotension

  • After repeat fluid boluses and with sodium load from NaHCO3 norepinepherine should be the first line vasopressor

Dialysis

Not useful

Disposition

  • Consider discharge for pts who remain asymptomatic after 6hr of observation

See Also

Source

  • Tintinalli
  • UpToDate
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