Sodium bicarbonate for life-threatening sodium-channel blocker toxicity
Class I recommendation in toxicology-focused resuscitation guidance
Benzodiazepines for toxin-induced seizures
Standard of care consensus
Norepinephrine for vasodilatory shock
Class I recommendation in shock management frameworks
Special Populations
Pregnancy
Pregnancy considerations
Maternal priorities
Maternal stabilization as fetal stabilization
Left lateral tilt in late pregnancy
Monitoring
Fetal monitoring after maternal stabilization when viable gestation
Medications
Sodium bicarbonate use acceptable when indicated
Benzodiazepines risk benefit in life-threatening seizures
Disposition
Obstetrics consultation for viable gestation
Geriatric
Older adult considerations
Higher baseline conduction disease prevalence
Lower threshold for ICU
Medication effects
Increased anticholinergic sensitivity
Fluid strategy
Lower bolus volumes with frequent reassessment
Pediatrics
Pediatric considerations
Rapid deterioration risk
Early PICU involvement
Weight-based dosing
Sodium bicarbonate 1 to 2 mEq/kg bolus
Benzodiazepines weight-based dosing
Observation
Minimum 6 hour monitoring for asymptomatic ingestion with normal ECG
Background
Epidemiology
Epidemiology
Exposure patterns
Common cause of life-threatening antidepressant poisoning despite reduced prescribing
Time course
Onset typically within 1 to 2 hours after ingestion
Highest risk window within first 6 hours
Morbidity drivers
Ventricular dysrhythmia
Refractory hypotension
Seizures
Pathophysiology
Mechanisms
Fast sodium-channel blockade
QRS widening
Ventricular dysrhythmia
Potassium-channel effects
QT prolongation
Alpha-1 blockade
Hypotension
Anticholinergic effects
Delirium
Ileus
Hyperthermia
GABA antagonism
Seizures
High protein binding and large volume of distribution
Limited dialyzability
Therapeutic Considerations
Rationale for alkalinization
Increased extracellular sodium concentration
Competitive relief of sodium-channel blockade
Serum alkalemia
Reduced free fraction of TCA
Reduced binding to sodium channels
Target pH 7.50 to 7.55
Balance of efficacy and alkalemia risk
Why certain therapies are avoided
Class Ia and Ic antiarrhythmics worsen sodium-channel blockade
Physostigmine risk in TCA cardiotoxicity
Phenytoin may worsen dysrhythmia in sodium-channel blockade
Dialysis limitations
Ineffective due to high protein binding and tissue distribution
Patient Discharge Instructions
copy discharge instructions
Discharge guidance
What happened
Medication overdose can affect heart rhythm and brain function
What to do now
Take medicines only as prescribed
Store medicines locked and out of reach
Avoid alcohol and sedating drugs unless prescribed
Follow-up
Primary care follow-up within 1 to 3 days
Mental health follow-up if overdose was intentional or unclear
Return to ED now if
Fainting or near-fainting
Seizure
New confusion
Chest pain
Fast or irregular heartbeat
Trouble breathing
Persistent vomiting
Severe weakness
References
Clinical guidelines and key sources
Core references
American Heart Association focused update on poisoning and envenomation in resuscitation
Sodium bicarbonate for life-threatening sodium-channel blocker toxicity
GEMNet guideline for management of tricyclic antidepressant overdose
Sodium bicarbonate bolus strategies
Ontario Poison Centre sodium-channel blocker QRS widening treatment sheet
NaHCO3 1 to 2 mEq/kg for QRS greater than 100 ms
Royal Children’s Hospital clinical guideline for TCA poisoning
Sodium bicarbonate 2 mmol/kg for QRS widening or ventricular arrhythmia
Boehnert and Lovejoy tricyclic antidepressant poisoning ECG predictors
QRS duration association with seizures and dysrhythmia
Review of sodium bicarbonate use in sodium-channel blocker poisoning
Evidence synthesis for QRS narrowing effect
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