Activated charcoal: the untold story

Accident and Emergency Nursing (2003) 11, 63–67 0965-2302/03/$ - see front matter ª 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0965-2302(02)00201-1

Activated charcoal: the untold story Richard M. Lynch, Robert Robertson

Richard M. Lynch FRCSI, MMedSci. Specialist Registrar in Accident and Emergency, Hull Royal Infirmary Robert Robertson FRCS Associate Specialist in Accident and Emergency, Hull Royal Infirmary Correspondence to: Richard M Lynch FRCSI, MMedSci., Specialist Registrar in Accident and Emergency, Accident and Emergency Department, York District Hospital, Wigginton Road, York YO31 8HE, UK. Tel.: +44-1904726042; E-mail: rlynch@ tinyworld.co.uk Manuscript received: 8 September 2002; accepted: 22 September 2002

Introduction. To identify the prevalence and appropriateness of prescribing activated charcoal in the management of acute poisoning and to document patient compliance with treatment. Methods. A prospective study was conducted, between October 1998 and September 1999, on patients attending our accident and emergency department, with a history of overdose. Overdoses were classified as potentially toxic or non-toxic according to the history and/or information received from the National Poisons Information Service. Results. Two hundred and seventy five patients presented following overdose; 17% within one hour, 102 were prescribed charcoal (37.1%) but of these, 40 (39%) refused it, and of the 62 patients (61%) who accepted charcoal only 15 (24.2%) took all that was prescribed. Patients were 5.4 times more likely to take charcoal if they had taken a potentially toxic overdose. Of those who presented within one hour and were judged to have taken a potentially toxic overdose, only three patients took the full-prescribed amount. Conclusion. We report a substantially greater proportion of patients (39%) refusing charcoal than previously reported (9.9%). The widespread availability of TOXBASE should help redress this discrepancy. c 2003 Elsevier Science Ltd. All rights reserved.

Introduction Gastric decontaminating procedures in the medical management of acute poisoning have changed considerably in the past decade (MacNamara et al. 1996). A greater emphasis is now placed on the early use of activated charcoal, with recommendations that it should be considered in patients who have ingested a potentially toxic amount of a poison (which is known to be adsorbed to charcoal) up to one hour previously (Position statement 1997). Meanwhile some authors suggest that it may be reasonable to give activated charcoal within two hours of overdose (Vale & Proudfoot 1993; Bateman 1999). However, there is no evidence that activated charcoal actually improves clinical outcome (Bradberry & Vale 1995; Henry & Hoffman 1998) despite isolated reports demonstrating enhanced elimination of certain

ª 2003 Elsevier Science Ltd. All rights reserved.

poisons (Gal et al. 1984; Neuvonen 1982). Additionally, supportive data for the effectiveness of repeated dose charcoal is also lacking (Pond et al. 1984). Activated-charcoal treatment is typically commenced within the accident and emergency (A&E) department despite the lack of evidence demonstrating its effectiveness and the lack of consensus among A&E doctors in their methods of gastric decontamination (Greaves et al. 1996). Little is published in the literature reporting the proportions of patients who actually take charcoal, when offered, and how much they actually consume. This study was therefore, undertaken to evaluate (a) the prevalence and appropriateness of prescribing activated charcoal in the management of acute poisoning in our A&E department, and (b) to identify the

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Activated charcoal: the untold story

percentage of patients who actually take charcoal, when prescribed, and the amount they consume.

Methods A prospective study was conducted, between October 1998 and September 1999, on all patients attending the A&E department of Hull Royal Infirmary with a history of overdose. Patients were identified at the time of presentation and a data collection form was completed by the attending doctor. To avoid missing any eligible patients a thorough search of the departmental computer database was performed to identify any patients whose presenting complaint or discharge diagnosis was recorded as overdose. The case notes of these patients were then retrieved to collect the required data. Patients who took an overdose of an intravenous compound were excluded from the study. Data collected included name and quantity of substance or substances allegedly ingested, interval from ingestion to presentation, history of vomiting, frequency of prescribing charcoal, acceptance or refusal of treatment, and quantity of charcoal consumed. Patients were not aware that this information was being collected as we felt it would probably influence their decision to take charcoal or not. We attempted to study the prevalence and appropriateness of prescribing activated charcoal in the management of acute poisoning and to document patient compliance with treatment without the presence of confounding factors. Furthermore, we were not altering clinical management of patients but simply documenting ‘current’ practice. Overdoses were classified as potentially toxic or non-toxic according to the history given by the patient or relative and/or information received from the National Poisons Information Service at the time of presentation.

Results A presenting complaint of overdose was identified in 275 patients attending the A&E department of Hull Royal Infirmary during the study period. Table 1 illustrates the diversity of

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substances allegedly ingested, paracetamol containing compounds being the most common accounting for 43.6% of all presentations. Patients (40.4%) presented within 2 hours of overdose (Fig. 1). One hundred and forty two (51.6%) had taken alcohol concurrently at the time of overdose. Activated charcoal was prescribed in 102 cases (37.1%) but of these, 40 (39%) refused it, and of the 62 patients (61%) who accepted charcoal only 15 (24.2%) took all that was prescribed to them (Table 2). Of those who took the full-prescribed amount of charcoal, six presented within one hour, six within 2 hours, and 3 within 4 hours. The mean quantity of activated charcoal taken by the other 47 patients was 27 g. There was a considerable spread of times at which patients presented following overdose. Forty seven patients (17%) presented within one hour (Fig. 1). Of these, 38 (80.9%) patients took a potentially toxic overdose and 9 (19.1%) a non-toxic overdose. Of those who presented within one hour and judged to have taken a potentially toxic overdose 63% (24 of 38) were prescribed charcoal, and of these 79% (19 of 24) took it but only three of these patients took the full complement of prescribed charcoal. Two of the patients who were not prescribed charcoal had allegedly ingested 50 g of paracetamol and presented within one hour of overdose. Among those who took a potentially nontoxic overdose, and presented within one hour, three had charcoal prescribed and two took it. Thus, the likelihood ratio of patients, who presented within one hour, following a potentially toxic overdose and being prescribed charcoal was 1.3. Within this group, patients

Table 1

Drugs taken in overdose

Drug Paracetamol Hypnotics/anxiolytics Aspirin Antidepressants Non-steroidals Tricyclic antidepressants Antipsychotics Antiepileptics Others Not recorded

Number of patients

Percentage (%)

120 40 20 18 16 12 12 10 18 9

43.6 14.5 7.3 6.5 5.8 4.4 4.4 3.6 6.6 3.3



Fig. 1 Time from overdose to presentation (NS ¼ Not stated).

Table 2 Numbers of patients prescribed charcoal and numbers who took it, for each class of drug taken Drug

Paracetamol Hypnotics/anxiolytics Aspirin Antidepressants Non-steroidals Tricyclic antidepressants Antipsychotics Antiepileptics Others Not recorded

Number of patients prescribed charcoal

Number of patients who took charcoal

51 6 13 7 7 5 8 3 0 2

32 2 8 4 5 3 4 2 0 2

patients were prescribed activated charcoal more than 24 hours following overdose. Four of these had taken an overdose of paracetamolcontaining compounds, one an antiepileptic agent and one an antipsychotic agent. Gastric lavage was recommended to eight patients (2.9%), three of whom refused it. Of the five who agreed to gastric lavage four had activated charcoal instilled into the stomach following the lavage. Repeat dose activated charcoal was given in 12 (4.4%) patients who presented following overdoses of tricyclic antidepressants or aspirin.

Discussion were 5.4 times more likely to take charcoal, when prescribed, if they had taken a potentially toxic overdose. Of the 102 patients prescribed activated charcoal, patients were 1.2 times more likely to take charcoal if they had taken a potentially toxic overdose compared with those who had not (likelihood ratio 1.2). Fig. 2 illustrates the numbers of patients prescribed activated charcoal based on their interval from overdose to presentation. Six


Activated charcoal has been used for the emergency treatment of acute poisoning and drug overdose for some time. It will adsorb most poisons to some extent but studies suggest that lithium, iron, strong acids, and alkalis are the exception (Saetta 1993). It appears to be associated with fewer serious complications than either emesis or gastric lavage (Neuvonen 1982) and side effects are infrequent (McLuckie et al. 1990). Activatedcharcoal works by three methods. Direct


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Fig. 2 Time from overdose to administration of charcoal (NS ¼ Not stated).

adsorption of poisons, adsorption of poisons, which undergo enterohepatic recycling, and adsorption of poisons, which are secreted directly into the gut e.g., digoxin, the so-called gastrointestinal dialysis (Levy 1982). While treatment is typically initiated within the A&E Department, Greaves et al. (1996) have demonstrated a lack of consensus among A&E doctors in their methods of gastric decontamination. This is highlighted by six of our patients who were prescribed activated charcoal more than 24 hours following overdose together with the lack of its use in patients presenting within 2 hours of overdose. Only 67 of 111 patients presenting within 2 hours of overdose were prescribed activated charcoal. It is difficult to state whether these discrepancies have been accentuated by the difficulties in taking an accurate medical history in cases of poisoning (Wright 1980). Our study reports consumption of similar mean quantities of activated charcoal as Boyd and Hanson (1999), 27 g versus 26.5 g, but a substantially greater proportion of patients (39%) refusing this treatment than has previously been reported (9.9%) (MacNamara et al. 1996).

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Gastric lavage has become increasingly less used in the management of poisoning within the A&E department in recent years. MacNamara et al. (1996) report a decline in frequency of utilisation of gastric lavage in the treatment of overdose from 75.2% in 1984 to 13% in 1994. In our study gastric lavage was recommended in 2.9% of patients while only 1.8% agreed to it, further highlighting its declining role in the management of acute poisoning. Concerns have been raised regarding its potential to further worsen poisoning by forcing the poison through the pylorus and thus aiding its absorption (Saetta et al. 1991). The large proportion of patients who refused to take charcoal is a cause for concern. This can be tackled by directing education at A&E doctors and nurses to increase their awareness and understanding of the role of activated charcoal in the early management of poisoning. The widespread availability of TOXBASEÓ should help redress this discrepancy. TOXBASEÓ is an internet-based information service provided by the National Poisons Information Service, which provides information and advice on the diagnosis,



treatment, and management of patients who may have been accidentally or deliberately poisoned. Additionally every reasonable effort should be undertaken to convince patients of the benefits and indications of activated charcoal. Repeated efforts at gentle persuasion should be employed where necessary to ensure a significantly larger proportion of patients take charcoal. This should take place side by side with further studies to help clarify whether or not charcoal has a beneficial effect in clinical outcome.

Conclusions While the emphasis in recent years in the early management of acute poisoning has been the early administration of activated charcoal, we have identified a much larger proportion of patients who refuse to take it than has previously been reported. Standardised guidelines should be in place in each A&E department to guide doctors to the correct and appropriate use of activated charcoal in the management of acute poisoning. References Bateman DN 1999 Gastric decontamination-a view for the millennium. Journal of Accident and Emergency Medicine 16: 84–86 Boyd R, Hanson J 1999 Prospective single blinded randomised controlled trial of two orally administered charcoal preparations. Journal of Accident and Emergency Medicine 16: 24–25 Bradberry SM, Vale JA 1995 Multiple-dose activated charcoal: a review of relevant clinical studies. Journal of Toxicology 3: 407–416


Gal P, Miller A, McCue JD 1984 Oral activated charcoal to enhance theophylline elimination in an acute overdose. Journal of the American Medical Association 251: 3130– 3131 Greaves I, Goodacre S, Grout P 1996 Management of drug overdoses in accident and emergency departments in the UK. Journal of Accident and Emergency Medicine 13: 46–48 Henry JA, Hoffman JR 1998 Continuing controversy on gut decontamination. Lancet 352: 420–421 Levy G 1982 Gastrointestinal clearance of drugs with activated charcoal. New England Journal of Medicine 307: 676–678 MacNamara AF, Riyat MS, Quinton DN 1996 The changing profile of poisoning and its management. Journal of the Royal Society of Medicine 89: 608–610 McLuckie A, Forbes AM, Ilett KF 1990 Role of repeated doses of oral-activated charcoal in the treatment of acute intoxications. Anaesthesia and Intensive Care 18: 375–384 Neuvonen PJ 1982 Clinical pharmokinetics of activated charcoal in acute intoxications. Clinical Pharmokinetics 7: 465–489 Pond SM, Olson KR, Osterloh JD, Tong TG 1984 Randomized study of the treatment of phenobarbital overdose with repeated doses of activated charcoal. Journal of the American Medical Association 251: 3104–3108 Position statement: single-dose activated charcoal 1997 American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists Clinical Toxicology 35: 721–741 Saetta JP 1993 Gastric decontaminating procedures: is it time to call a stop? Journal of the Royal Society of Medicine 86: 396–399 Saetta JP, Marsh S, Quinton DN 1991 Gastric-emptying procedures in the self-poisoned patient: are we forcing gastric content beyond the pylorus? Journal of the Royal Society of Medicine 84: 274–276 Vale JA, Proudfoot AT 1993 How useful is activated charcoal? British Medical Journal 306: 78–79 Wright N 1980 Common errors in the management of poisoning. Journal of the Royal College of Physicians London 14: 114–116


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