Activated Charcoal – To give or not to give?

Activated Charcoal (AC): To give or not to give?

By Dr. Ferrari

(Reviewed by deSouza)

History of Activated Charcoal

• 1831 French Academy of Medicine: Tovery takes AC with a lethal dose of strychnine without symptoms
  
• 1960s, review article in Journal of Pediatrics, popularizes its use
  
  • Standard at this time was gastric decontamination followed by AC
    

What is Activated Charcoal?

1. Synthesis: Pulverized carbonaceous materials (sawdust, peat or coconut shells) is heated to 600-900°C
   
2. Activation: Steam or hot air erodes the surface thereby increasing surface area
   

   – Net Surface Area: 800-1200m²/g (normal), 2800-3500 m²/g (superactivated)

Mechanism

• Absorption
  
  • Weak intermolecular bonds (Van der Waals)
    
  • Organic, large, poorly water soluble
    
  • Correlates with volume of distribution
    
• Disruption of enterohepatic circulation
  
  • Toxins are conjugated in liver by glucuronides
    
  • Dumped back into intestine
    
  • Hydrolysis by beta-glucuronidase frees toxin to be reabsorbed
    
  • Charcoal can bind before reabsorption
    
• Back Diffusion – “Gastrointestinal Dialysis”
  
  • Drug diffuses from circulation back into intestinal tract
    
  • Studies of IV drug administration treated with AC show reduction in T_1/2 (theophylline and digoxin)
    

Nuts & Bolts

• Dose: AC grams:drug grams or 1g/kg
  

  10:1

  40:1

• Contraindications
  
  • Caustic/volatile substances
    
  • Active vomiting
    
    • Consider antiemetics
      
  • Can’t protect airway
    
    • Able to protect airway – drink it
      
    • Unable to protect airway – Intubate and provide by NG tube
      
  • Known not to bind: iron, lithium, potassium, ethanol
    

Complications

• Vomiting
  
• Aspiration pneumonitis
  
• Constipation or diarrhea (with cathartics)
  
• Cases: appendicitis, perforation
  

Guidelines

• “In the absence of satisfactorily designed clinical studies demonstrating benefit from its use, the administration of activated charcoal may be considered if a patient has ingested a potentially toxic amount of a poison up to one hour following ingestion. The potential for benefit after one hour cannot be excluded.”
  

Position Paper: Single-Dose Activated Charcoal

American Academy of Clinical Toxicology and European Association of Poisons Centres and Clinical Toxicologists

• “50g AC to cooperative, awake adult within 2 hours of ingestion of toxic dose of intermediate-release acetaminophen and 4 hours of modified-release acetaminophen…For doses of greater than 30g, AC up to 4hrs…For massive modified-release acetaminophen, absorption may continue for 24hrs and patients may still benefit from activated charcoal after 4hrs”
  

Summary Statement: new guidelines for the management of paracetamol poisoning in Australia and New Zealand

Debate

• Does it work?
  
  • Many studies show reduction in toxin concentration
    
    • Varying levels of quality of evidence
      
  • No study shows improvement in morbidity, mortality, ICU or hospital length of stay
    
• Why 1hr?
  
  • Multiple studies show decreased efficacy after 1hr
    
    • Riddled with mixed data due to concurrent gastric lavage/ use of ipecac
      
  • Multiple studies show good efficacy at 2hrs
    
  • Some studies show efficacy at 4hrs
    
  • Minimal convincing data after 4hrs
    
  • Prolonged Gastric Emptying Half-Time and Gastric Hypomotility After Drug Overdose (Adams, AJEM 2003)
    
    • TCA, acetaminophen, opiod-acetaminophen, carbamazepine, phenytoin
      
    • Gastric scintigraphy after overdose compared to scintigraphy after recovery (control)
      
    • Mean age: 29 years, 75% Female, 25% Male
      
    • Median: 94 min with overdose, 36 min control
      
  • Pharmacokinetics of digoxin cross-reacting substances in patients with acute yellow oleander (Thevetia peruviana) poisoning, including the effect of activated charcoal (Roberts, Therapeutic Drug Monitoring, 2006)
    
    • Terminal half-life of yellow oleander decreased by 50% in those who received AC
      
      • Mean 33.9hrs v 62.9hrs
        

Bottom line

• Always consider it
  
• There is a risk/Benefit balance
  
• On the In-Service exam: give within 1hr of ingestion for appropriate substances in individuals who can protect their airway
  

Edited by Dr. deSouza

References:

Adams BK, Mann MD, Aboo A, Isaacs S, Evans A. Prolonged gastric emptying half-time and gastric hypomotility after drug overdose. Am J Emerg Med. 2004 Nov;22(7):548-54. PubMed PMID: 15666259.

Derlet RW, Albertson TE. Activated charcoal–past, present and future. West J Med. 1986 Oct;145(4):493-6. Review. PubMed PMID: 3538661; PubMed Central PMCID: PMC1306980.

Olson KR. Activated charcoal for acute poisoning: one toxicologist’s journey. J Med Toxicol. 2010 Jun;6(2):190-8. doi: 10.1007/s13181-010-0046-1. Review. PubMed PMID: 20490748; PubMed Central PMCID: PMC2919687.

Roberts DM, Southcott E, Potter JM, Roberts MS, Eddleston M, Buckley NA. Pharmacokinetics of digoxin cross-reacting substances in patients with acute yellow Oleander (Thevetia peruviana) poisoning, including the effect of activated

charcoal. Ther Drug Monit. 2006 Dec;28(6):784-92. PubMed PMID: 17164695; PubMed Central PMCID: PMC2296884.

Yeates PJ, Thomas SH. Effectiveness of delayed activated charcoal administration in simulated paracetamol (acetaminophen) overdose. Br J Clin Pharmacol. 2000 Jan;49(1):11-4. PubMed PMID: 10606832; PubMed Central PMCID: PMC2014891.

Position Paper: Single-Dose Activated Charcoal, American Academy of Clinical Toxicology and European Association of Poisons Centres and Clinical Toxicologists, (https://www.clintox.org/documents/positionpapers/SingleDoseActivatedCharcoal.pdf), 2005

Summary Statement: new guidelines for the management of paracetamol poisoning in Australia and New Zealand, (www.mja.com.au/sites/default/files/issues/203_05/Guidelines_paracetamol_Aus_NZ_2015.pdf), 2015

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