Toxicological

  • Activated Charcoal
  • N-Acetylcystiene
  • Naloxone
  • Thiamine

Activated Charcoal

  • Mechanism of Action: Adsorbent agent. Large surface area of charcoal binds to toxins and prevents systemic absorption.
  • Indications: Toxic ingestions/drug overdoses (solids only); should be administered within 1-2 hours of ingestion.
  • Contraindications: Risk of aspiration, ingestion of caustic material
  • Dosage: 25-100mg PO
  • Onset: Begins within 1 minute; achieves equilibrium within 10-25 minutes.
  • Duration: Up to 4 hours
  • Adverse Reactions: aspiration, bowel obstruction.
  • Special Considerations: N/A
Video Credit: Medicalomics

*Deep Dive: Back to Black: A Review of Activated Charcoal (EM Ottawa)



N-Acetylcysteine

  • Mechanism of Action: Antidote/Mucolytic; helps replete glutathione reserves in the liver, which helps protect the liver from hepatotoxic NAPQI metabolite. Also functions as a mucolytic to help break down thick pulmonary secretions.
  • Indications: Acetaminophen toxicity
  • Contraindications: Allergy to drug/class
  • Dosage: Three separate infusions:
    • First dose: 150mg/kg in 100 mL D5W over 60 minutes
    • Second dose: 50mg/kg in 250 mL D5W over 4 hours
    • Third dose: 100 mg/kg in 500 mL D5W over 16 hours
  • Onset: Generally rapid onset
  • Duration: Generally short duration
  • Adverse Reactions: Nausea/vomiting, anaphylaxis 
  • Special Considerations: Almost 100% effective if given within 8 hours of ingestion for maximum benefit. May still be beneficial after >24 hours.
Video Credit: Respiratory Therapy Zone

*Deep Dive: N-acetylcysteine (Life in the Fast Lane)



Naloxone

  • Mechanism of Action: Opiate antagonist; competitively binds to mu, kappa, and sigma opiate receptor sites in the CNS for reversal of opiate toxicity and improvement of respiratory drive.
  • Indications: Opioid toxicity (recreational or iatrogenic)
  • Contraindications: Allergy to class/drug
  • Dosage: 0.4 – 2.0 mg (IV/IM/SC), repeat q 2-3 minutes prn. Max dose 10 mg
  • Onset: 1-2 minutes
  • Duration: 20-90 minutes
  • Adverse Reactions: Non-cardiogenic pulmonary edema, opioid withdrawal (diaphoresis, tachycardia, agitation)
  • Special Considerations: Patients with opiate overdose should be held in the ED until naloxone wears off (usually 1-3 hours). Consider discharging patients with naloxone in-hand. 
Video Credit: Lights Sirens Action EMS

*Deep Dive: Narcan or Nar-can’t: Tips and Tricks to Safely Reversing Opioid Toxicity (EM:RAP)



Thiamine

  • Mechanism of Action: Vitamin; combines with ATP in liver, kidneys, and leukocytes to produce thiamine diphosphate, which acts as a coenzyme in carbohydrate metabolism. Used to prevent brain damage (encephalopathy) from thiamine-depleted states.
  • Indications: Alcoholism, beriberi anorexia, bulimia, pregnancy, malignancies
  • Contraindications: Allergic reactions to vitamin supplements
  • Dosage
    • Beriberi: 5-30 mg TID x 1 month
    • Wernicke’s Encephalopathy: 500mg IV TID x 2 days
  • Onset: Rapid
  • Duration: Depends on degree of deficency
  • Adverse Reactions: Anaphylaxis, pruritus, injection site pain
  • Special Considerations: None
Video Credit: Medicosis

*Deep Dive: Myths of Toxicology: Thiamine Before Dextrose (Emergency Medicine News)


Brandon Simpson, PA-S2
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