Activated Charcoal

From Anvita Health Wiki

Contents 1 Introduction 2 Indications 3 Contraindications 4 Dosage 5 Monitor 6 Drug-interactions 7 Mechanism-of-action 8 More General Terms 9 Additional Terms 10 References

Introduction

• Produced by heating wood pulp to 900 degrees C, washing, then activating with steam of strong acid.

• Absorbs a wide variety of toxins ranging in size from 100-1000 g/mol preventing their absorption from the GI tract.

Indications

• general purpose antidote for oral poisonings
• when using in combination with ipecac, induction of vomiting must be complete prior to use of activated charcoal
• uremia: absorbs creatinine, uric acid, urea & organic acids from GI tract
• most effective within 30 minutes of poison ingestion
• generally given with a cathartic

• either sorbitol or magnesium citrate

Contraindications

• activated charcoal does not absorb:

• heavy metals - iron
• lithium
• alcohols
• high ionized compounds
• caustic agents
• cyanide

• factors which render activated charcoal less useful

• non-toxic ingestions
• very small ingestions
• maximum toxic effect reached or passed
• suspension or liquid (except paraquat/ diquat)
• risk of aspiration > benefit of charcoal

• pregnancy-category +
• safety in lactation +

Dosage

• 50 g alone plus 50 g with 50 g of sorbitol (adults)
• 1-2 gm/kg (children)
• 50 g every 4 hours for adults with 50 g of sorbitol no more than every 3rd dose of charcoal
• 10 times the estimated amount of drug [4]
• administered as a well-mixed slurry
• cathartics with 1st dose only
• multiple doses of charcoal necessary

• phenobarbital, carbamazepine, quinine, dapsone, theophylline
• possibly: salicylates, digitoxin, phenytoin

Monitor

• bowel sound to avoid impactation in the event of ileus

Drug-interactions

• multiple dose activated charcoal may enhance excretion of theophylline, phenobarbital, phenytoin, carbamazepine.

Mechanism-of-action

• small pores capable of adsorbing molecules 100-1000 g/mol
• a gram of activated charcoal has approximately 1000 square meters of surface area
• reversible adsorption of toxins

• preventing absorption from the GI tract
• interrupts enterohepatic recirculation of some drugs & toxins
• diffusable drugs may cross into the gut from the bloodstream (gut dialysis) [4]

More General Terms

• antidote

Additional Terms

• toxicity; poisoning; overdose

References

1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 1161
2. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
3. Department of Veterans Affairs, VA National Formulary
4. Daubert GP, Emergency Medicine, University of California, Davis

activated charcoal {with sorbitol} (Insta-Char, Actidose)