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Three Part Question

In [patients poisoned with paracetamol] does [activated charcoal alone or in combination with other treatments] reduce [hepatotoxicity]?

Clinical Scenario

A 23 year old woman attends the Emergency Department having taken 60 500mg paracetamol tablets 2 hours prior to presentation. You wonder whether she should receive activvated charcoal.

Search Strategy

Medline 1966-03/00 using the OVID interface.
[({acetaminophen.mp OR paracetamol.mp} AND {exp poisoning OR poisoning.mp OR exp overdose OR overdose.mp}) AND {exp charcoal OR charcoal.mp} LIMIT to human AND english.

Search Outcome

71 papers found of which 68 were irrelevant or of insufficient quality. The remaining 3 papers are shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Underhill TJ et al, 1990, UK	60 patients who had taken 5 gm or more of paracetamol within 4 hours of attendance. Gastric lavage (14) vs ipecacuana (21) vs activated charcoal (20) vs nothing (5)	RCT	Plasma concentrations at 0, 60, 90 and 150 minutes post treatment	Activated charcoal group had significantly better fall in paracetamol concentration at 150 min	Small study
Spiller HA et al, 1994, USA	122 patients with paracetamol overdose within the previous 12 hours. Activated charcoal (40) vs activated charcoal and N acetylcysteine (57) vs activated charcoal and high dose N acetyl cysteine (25)	Observational study	Hepatotocxicity (defined as SGOT over 125 units/l)	Significantly less (5% vs 20%) in groups receiving activated charcoal	Spectrum is of patients contacting a poisons centre. No power study.
Buckley NA et al, 1999, Australia	981 consecutive paracetamol poisonings. Gastric lavage and charcoal vs charcoal alone vs nothing	Observational study	Risk of "high risk" concentrartion	Significantly less change of toxic level if activated charcoal given (Odds Ratio 0.36 {0.23 - 0.58})

Comment(s)

There are no high quality studies in this area. In particular there is no data to indicate how long after poisoning activated charcoal remains effective.

Clinical Bottom Line

Activated charcoal should be given to all patients with significant paracetamol poisoning who present acutely.

References

1. Underhill TJ, Greene MK, Dove AF. A comparison of the efficacy of gastric lavage, ipecacuanha and activated charcoal in the emergency management of paracetamol overdose. Arch Emerg Med 1990;7(3):148-54.
2. Spiller HA, Krenzelok EP, Grande GA et al. A prospective evaluation of the effect of activated charcoal before oral N acetylcysteine in acetaminophen overdose. Ann Emerg Med 1994;23(3):519-23.
3. Buckley NA, Whyte IM, O'Connell DL et al. Activated charcoal reduces the need for N-acetylcysteine treatment after acetaminophen (paracetamol) overdose. J Toxicol - Clin Toxicol 1999;37(6):753-7.