What is the recommended dosage and administration timing of activated charcoal (AC) in cases of suspected poisoning or drug overdose?

Activated Charcoal Dosage and Administration in Poisoning Cases

For suspected poisoning or drug overdose, activated charcoal should be administered at a dose of 1 g/kg body weight (50-100g for adults) as soon as possible, ideally within 1 hour of ingestion. 1, 2

Timing of Administration

Activated charcoal effectiveness is time-dependent:

• Most effective when given within 1 hour of ingestion 3, 4
• For acetaminophen overdose specifically, administer within 4 hours of presentation 5
• For extended-release medications, may be effective up to 6 hours after ingestion 1

Dosing Guidelines

Adults:

• Standard dose: 50-100g as a single dose 1
• Weight-based alternative: 1g/kg body weight 1, 6

Children:

• 0.5-1g/kg body weight 1

Administration Considerations

• Administer as an oral slurry or via nasogastric tube if the patient cannot take it orally
• For acetaminophen overdose, give activated charcoal just prior to starting N-acetylcysteine (NAC) 5
• Commercially available preparations often contain sorbitol as a cathartic agent 5
• Non-sorbitol containing products should be used for children under 1 year and when repeated doses are necessary 5

Multiple Dose Regimens

Multiple doses may be indicated for:

• Drugs with extended-release formulations
• Medications with significant enterohepatic or entero-enteric circulation
• Substances that persist longer in the stomach 1

For multiple dose regimens:

• After initial dose, administer 0.5g/kg every 4-6 hours 6
• Continue until charcoal appears in stool 6
• Monitor for fluid/electrolyte imbalances, especially in children 6

Contraindications and Limitations

• Impaired consciousness with risk of aspiration (unless airway is secured) 1
• Ineffective for poisoning with: acids, bases, alcohols, organic solvents, inorganic salts, metals, iron, lithium, and potassium 5, 1
• Risk of aspiration may outweigh benefits if airway protective reflexes are impaired 5

Important Clinical Pearls

1. Prehospital administration can significantly reduce time to treatment (5 minutes vs. 51.4 minutes when delayed until ED arrival) 7

2. Consult poison control center before administration (800-222-1222 in the US) 5, 1

3. Research shows that activated charcoal reduces drug bioavailability by approximately 30% when given at 1 hour, but shows no significant reduction when given at 2 or 3 hours post-ingestion 3

4. Routine combination with laxatives is not recommended 1

5. The risk-benefit analysis should be individualized for each case of suspected poisoning, with particular attention to the substance ingested and time since ingestion 1