Comparison of activated charcoal and ipecac syrup in prevention of drug absorption

Systematic review on the use of activated charcoal for gastrointestinal decontamination following acute oral overdose

INTRODUCTION

The use of activated charcoal in poisoning remains both a pillar of modern toxicology and a source of debate. Following the publication of the joint position statements on the use of single-dose and multiple-dose activated charcoal by the American Academy of Clinical Toxicology and the European Association of Poison Centres and Clinical Toxicologists, the routine use of activated charcoal declined. Over subsequent years, many new pharmaceuticals became available in modified or alternative-release formulations and additional data on gastric emptying time in poisoning was published, challenging previous assumptions about absorption kinetics. The American Academy of Clinical Toxicology, the European Association of Poison Centres and Clinical Toxicologists and the Asia Pacific Association of Medical Toxicology founded the Clinical Toxicology Recommendations Collaborative to create a framework for evidence-based recommendations for the management of poisoned patients. The activated charcoal workgroup of the Clinical Toxicology Recommendations Collaborative was tasked with reviewing systematically the evidence pertaining to the use of activated charcoal in poisoning in order to update the previous recommendations.

OBJECTIVES

The main objective was: Does oral activated charcoal given to adults or children prevent toxicity or improve clinical outcome and survival of poisoned patients compared to those who do not receive charcoal?  Secondary objectives were to evaluate pharmacokinetic outcomes, the role of cathartics, and adverse events to charcoal administration. This systematic review summarizes the available evidence on the efficacy of activated charcoal.

METHODS

A medical librarian created a systematic search strategy for Medline (Ovid), subsequently translated for Embase (via Ovid), CINAHL (via EBSCO), BIOSIS Previews (via Ovid), Web of Science, Scopus, and the Cochrane Library/DARE. All databases were searched from inception to December 31, 2019. There were no language limitations.  One author screened all citations identified in the search based on predefined inclusion/exclusion criteria. Excluded citations were confirmed by an additional author and remaining articles were obtained in full text and evaluated by at least two authors for inclusion. All authors cross-referenced full-text articles to identify articles missed in the searches. Data from included articles were extracted by the authors on a standardized spreadsheet and two authors used the GRADE methodology to independently assess the quality and risk of bias of each included study.

RESULTS

From 22,950 titles originally identified, the final data set consisted of 296 human studies, 118 animal studies, and 145 in vitro studies. Also included were 71 human and two animal studies that reported adverse events. The quality was judged to have a Low or Very Low GRADE in 469 (83%) of the studies. Ninety studies were judged to be of Moderate or High GRADE. The higher GRADE studies reported on the following drugs: paracetamol (acetaminophen), phenobarbital, carbamazepine, cardiac glycosides (digoxin and oleander), ethanol, iron, salicylates, theophylline, tricyclic antidepressants, and valproate. Data on newer pharmaceuticals not reviewed in the previous American Academy of Clinical Toxicology/European Association of Poison Centres and Clinical Toxicologists statements such as quetiapine, olanzapine, citalopram, and Factor Xa inhibitors were included. No studies on the optimal dosing for either single-dose or multiple-dose activated charcoal were found. In the reviewed clinical data, the time of administration of the first dose of charcoal was beyond one hour in 97% (n = 1006 individuals), beyond two hours in 36% (n = 491 individuals), and beyond 12 h in 4% (n = 43 individuals) whereas the timing of the first dose in controlled studies was within one hour of ingestion in 48% (n = 2359 individuals) and beyond two hours in 36% (n = 484) of individuals.

CONCLUSIONS

This systematic review found heterogenous data. The higher GRADE data was focused on a few select poisonings, while studies that addressed patients with unknown and or mixed ingestions were hampered by low rates of clinically meaningful toxicity or death.  Despite these limitations, they reported a benefit of activated charcoal beyond one hour in many clinical scenarios.

Novel method to estimate the appropriate dosing interval for activated charcoal to avoid interaction with other drugs

PURPOSE

Activated charcoal is known to adsorb a variety of drugs concomitantly administered and reduce their intestinal absorption, and separating the dosing is considered a practical approach to avoid this drug interaction. The aim of the present study was to develop and validate a simple method to estimate the sufficient dosing interval to avoid drug interaction using the pharmacokinetic profile of the subject drugs administered alone and the amplitude of interaction upon simultaneous administration with activated charcoal.

METHODS

For each subject drug, the pharmacokinetic profile and the amplitude of interaction, as assessed by AUCR (the ratio of area under the plasma concentration-time curve (AUC) in the presence of activated charcoal to that in its absence), were collected from previous reports. The AUCR value was estimated based on the compartment model under the assumption that the subject drug in the first gastrointestinal compartment is immediately adsorbed to a certain extent upon the administration of activated charcoal. The estimated AUCR (AUCR_e) for each drug with certain dosing interval was compared with the respective AUCR value reported previously (AUCR_obs).

RESULTS

Among twenty concentration profiles for 14 subject drugs obtained from previous reports, 15 AUCR_e values fell in the range of 80-120% of the respective AUCR_obs values.

CONCLUSION

The developed method enabled estimation of the amplitude of DDI by activated charcoal administered in a certain dosing interval, whereas overestimation of AUCR_e was observed for drugs that undergo extensive enterohepatic circulation.

Bioequivalence studies of inhaled indacaterol maleate in healthy Chinese volunteers under gastrointestinal non-blocking or blocking with concomitant charcoal administration

BACKGROUND

Indacaterol is one of the long-acting beta₂-adrenergic agonists, referred as first-line monotherapy for Chronic obstructive pulmonary disease since 2011. Generic products are encouraged to benefit the large COPD patients in China, in which can provide more choices association with reduced cost and improve the quality of patient life.

OBJECTIVE

The three-part study consists of two independent cohorts of thirty-six subjects, aimed to evaluate the bioequivalence (BE) of two indacaterol formulations in gastrointestinal (GI) absorption charcoal-block or non-block conditions. One pilot study performed in six healthy subjects to determine the blocking effect of a new charcoal-based regimen on GI absorption after orally inhalation of indacaterol.

METHODS

Two BE studies were conducted with a randomized, open-label, 2-period crossover design in two independent 36-healthy-subject cohorts, equivalence in systemic and lung deposition was assessed after inhalation of a single dose of 150 μg indacaterol (test or reference formulation) alone or concomitant administration of charcoal. The charcoal-based regimen was improved by optimizing the dose and number of doses, and its blocking efficacy against GI absorption was assessed in a pilot study. Six healthy subjects received 9 g charcoal 10 min before, immediately after and 2 h after indacaterol (3 g/100 ml water × 3 times). Blood collected at predetermined time points up to 72 h. Plasma indacaterol concentrations were determined using HPLC-MS/MS. Pharmacokinetics parameters were calculated with non-compartment analysis. Equivalences were concluded if the 90% confidence interval (CI) for test: reference of C_max and AUC_0-t fell within the limits of 0.8-1.25.

RESULTS

Indacaterol was undetectable in plasma samples in pilot study. The T/R ratio of the geometric mean C_max and AUC_0-t was 109.9% (90% CI, 106.1-113.8%) and 104.8% (90% CI, 101.5-108.1%) for charcoal-block subjects and 105.4% (90% CI, 99.8% ~ 111.3%), and 101.0% (90% CI, 97.7%-104.4%) for non-block subjects. No serious adverse events were reported.

CONCLUSIONS

The results showed that 150 μg indacaterol (+/- 9 g charcoal) was well tolerated in all subjects. The two formulations are bioequivalent in terms of the rate and absorption both in charcoal-block and non-block conditions. The improved charcoal-based regimen demonstrated to be effective and fully blockade of GI absorption of indacaterol.

Gastric Emptying Procedures in the Self-Poisoned Patient: Are we Forcing Gastric Content beyond the Pylorus?

A prospective, randomized, single-blind study was carried out to determine whether gastric content is forced into the small bowel when gastric-emptying procedures are employed in self-poisoned patients. They were asked to swallow barium-impregnated polythene pellets, immediately prior to either gastric lavage or ipecacuanha-induced emesis. A second group of patients, who did not require treatment, were used as controls. Sixty patients were recruited to the study. The data show a significant difference in the number of residual pellets in the small bowel of the treated group (n=40), when compared with the control group (P < 0.0001). There was no statistical difference in the number of pellets in the small bowel when the treated groups were compared with each other. In addition, the inefficiency of gastric-emptying procedures is highlighted; 58.5% of the total number of pellets ingested were retained in the gastrointestinal tract of the ipecacuanha-treated group, while 51.8% of total pellets ingested were retained in the gastric lavage-treated group.

Adsorption of Biologically Active Compounds from Aqueous Solutions on to Commercial Unmodified Activated Carbons. Part IV. Do the Properties of Amphoteric Carbon Surface Layers Influence the Adsorption of Paracetamol at Acidic pH Levels?

Three previously characterised, unmodified commercial activated carbons (D43/1, WD and AHD), differing in porosity and surface layer composition, were further examined using some additional methods of surface chemical description (electrochemical studies, acid–base site distribution, pHPZC and resistance measurements). Paracetamol adsorption isotherms (as well as kinetic curves) were measured on these carbons at acidic pH (1.5) and three temperatures, i.e. 300, 310 and 320 K. Measurements of the enthalpies of immersion in HCl and paracetamol solutions were also performed at 310 K, and diffusion coefficients and energies calculated.

The results of measurements at acidic pH were compared with those obtained under neutral pH conditions. Some new correlations between the properties of the carbon surface and the constants characterising the process of paracetamol adsorption suggested recently were extended from data measured initially for six carbons. The mechanism of adsorption at both pH values was elaborated with the importance of surface carbonyls and basic groups being emphasised. The adsorption of the polymerisation product of paracetamol at acidic pH was determined using FT-IR and UV–vis spectroscopic measurements.

Plant poisonings in children in the Czech Republic, 1996-2001

Ingestion of or exposure to potentially poisonous plants is a relatively common presenting complaint in hospital paediatric departments, especially amongst toddlers. We present a retrospective study conducted to review the hospital admissions following acute childhood poisoning with plants in the Czech Republic over a 6-year period from 1996 to 2001. Six university hospital paediatric departments and two local hospital paediatric departments were involved in the study. Information and complete data on the cases were collected on the basis of all hospital medical records and internal hospital database outcomes. A total of 174 plant exposures were analysed to tabulate the list of top species involved in plant poisonings. The aims were to provide classification according to agent frequency, clinical presentations, severity of symptoms expressed, affected age groups and gender of patients and to evaluate the treatment according to patient outcome. The most frequent ingestions were of thorn apple seeds (14.9%), followed by dumb cane exposures (11.5%) and common yew (9.8%). Thorn apple, dumb cane, golden chain and raw beans caused the most serious symptoms. There were no fatalities reported out of the reviewed medical records. Complete data on plant poisoning in children from all over the territory of the Czech Republic are not available; however, we believe that the frequency of causes and the rank of plant species commonly involved are properly reflected in our study.

Gastrointestinal decontamination

Why has ipecac syrup become less popular in emergency management of poisoning and overdose? When should gastric lavage, activated charcoal, cathartics, or a combination of methods be used? Which patients are candidates for whole-bowel irrigation with polyethylene glycol-electrolyte solution? Drs Harris and Kingston answer these questions and present their recommendations for each of the available management options.

EJCP and clinical toxicology: the first 40 years

INTRODUCTION

The European Journal of Clinical Pharmacology is now 40 years old and its history and development parallel developments in the related discipline of clinical (medical) toxicology. The journal has published many papers over its history that have informed its readers of scientific advances that link clinical pharmacology and clinical toxicology.

DISCUSSION

This review will provide an overview of the developments in treatment of poisoning and how effects of poisoning may provide information for drug regulation and suggests ways in which developments in pharmacogenetics and metabolomics may stimulate future research in this area.

Interventions for paracetamol (acetaminophen) overdose

BACKGROUND

Poisoning with paracetamol (acetaminophen) is a common cause of hepatotoxicity in the Western World. Inhibition of absorption, removal from the vascular system, antidotes, and liver transplantation are interventions for paracetamol poisoning.

OBJECTIVES

To assess the benefits and harms of interventions for paracetamol overdose.

SEARCH STRATEGY

We identified trials through electronic databases, manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies until December 2005.

SELECTION CRITERIA

Randomised clinical trials and observational studies were included.

DATA COLLECTION AND ANALYSIS

The primary outcome measure was all-cause mortality plus liver transplantation. Secondary outcome measures were clinical symptoms, (eg, hepatic encephalopathy, fulminant hepatic failure), hepatotoxicity, adverse events, and plasma paracetamol concentration. We used Peto odds ratios and odds ratios with 95% confidence intervals (CI) for analysis of outcomes. Random- and fixed-effects meta-analyses were performed.

MAIN RESULTS

Ten small and low-methodological quality randomised trials, one quasi-randomised study, and 48 observational studies were identified. It was not possible to perform relevant meta-analyses of randomised trials that have addressed our outcome measures. Activated charcoal, gastric lavage, and ipecacuanha are able to reduce the absorption of paracetamol, but the clinical benefit is unclear. Of these, activated charcoal seems to have the best risk-benefit ratio. N-acetylcysteine seems preferable to placebo/supportive treatment, dimercaprol, and cysteamine, but N-acetylcysteine's superiority to methionine is unproven. It is not clear which N-acetylcysteine treatment protocol offers the best efficacy. No strong evidence supports other interventions for paracetamol overdose. N-acetylcysteine may reduce mortality in patients with fulminant hepatic failure (Peto OR 0.26, 95% CI 0.09 to 0.94, one trial). Liver transplantation has the potential to be life saving in fulminant hepatic failure, but refinement of selection criteria for transplantation and long-term outcome reporting are required.

AUTHORS' CONCLUSIONS

Our results highlight a paucity of randomised trials on interventions for paracetamol overdose. Activated charcoal seems the best choice to reduce absorption. N-acetylcysteine should be given to patients with overdose but the selection criteria are not clear. No N-acetylcysteine regime has been shown to be more effective than any other. It is a delicate balance when to proceed to liver transplantation, which may be life-saving for patients with poor prognosis.

Diagnosis and management of the poisoned child

Pediatric toxic ingestions are treated commonly by pediatricians and emergency physicians. Significant injury after these ingestions is infrequent, but identifying the dangerous ingestion is sometimes a difficult task. By performing a detailed history, focused physical examination, and directed laboratory evaluation, an estimation of risk can be developed. This article introduced the term "toxic triage" to describe this process. The toxic triage estimation allows the clinician to make thoughtful decontamination and treatment decisions. Familiarity with the literature supporting or refuting each decontamination method allows educated decisions to be made. Supportive care is an integral part of treatment for all poisonings, from asymptomatic to life-threatening. Most antidotes are used rarely in clinical practice, but familiarity with common antidotes benefits those patients with specific hazardous ingestions. Prevention efforts have the potential to decrease the incidence of pediatric poisonings. The universal poison control center number provided should be distributed and posted in homes, clinics, and emergency departments.

Guideline on the use of ipecac syrup in the out-of-hospital management of ingested poisons

The use of gastric emptying techniques, including ipecac-induced emesis, in the management of poisoned patients has declined significantly in recent years. Historically, poison centers used ipecac syrup in two ways. Ipecac syrup was administered to patients prior to referral to the emergency department in attempts to start the gastric emptying process as early as possible. Additionally, poison centers used ipecac syrup in attempts to keep patients from requiring referral to medical facilities. In these situations, ipecac syrup was administered in the home and poison center staff performed follow-up telephone calls to gauge progress and outcome. Studies to determine the effectiveness of ipecac syrup demonstrate that it induces vomiting in a high percentage of people to whom it is administered and that it decreases the gastrointestinal absorption of ingested substances in a time-dependent fashion. However, the effectiveness of ipecac syrup in affecting patient outcome has not been studied in adequate clinical trials. Its effectiveness in preventing drug absorption has only been documented for a limited number of substances and is substantially reduced if it is given more than 30-90 minutes following ingestion of the toxic material. There are potentially significant contraindications, adverse effects and related problems associated with the use of ipecac syrup. It is the consensus of the panel that the circumstances in which ipecac-induced emesis is the appropriate or desired method of gastric decontamination are rare. The panel concluded that the use of ipecac syrup might have an acceptable benefit-to-risk ratio in rare situations in which: there is no contraindication to the use of ipecac syrup; and there is substantial risk of serious toxicity to the victim; and there is no alternative therapy available or effective to decrease gastrointestinal absorption (e.g., activated charcoal); and there will be a delay of greater than 1 hour before the patient will arrive at an emergency medical facility and ipecac syrup can be administered within 30-90 minutes of the ingestion; and ipecac syrup administration will not adversely affect more definitive treatment that might be provided at a hospital. In such circumstances, the administration of ipecac syrup should occur only in response to a specific recommendation from a poison center, emergency department physician, or other qualified medical personnel. The panel decided not to address the issue of whether ipecac should remain a nonprescription, over-the-counter product. The panel does not support the routine stocking of ipecac in all households with young children but was unable to reach consensus on which households with young children might benefit from stocking ipecac. Instead, the panel concluded that individual practitioners and poison control centers are best able to determine the particular patient population, geographic and other variables that might influence the decision to recommend having ipecac on hand.

Prolonged gastric emptying half-time and gastric hypomotility after drug overdose

A prospective study was undertaken to determine if gastric motility and emptying are altered by the ingestion of overdoses of tricyclic antidepressants, acetaminophen, opioid-acetaminophen mixtures, carbamazepine or phenytoin. Gastric scintigraphy was used to measure gastric emptying half-time and assess gastric motility in 104 patients at initial presentation and again at follow-up (n = 85). Patients were imaged for 5 hours after being given 20 MBq of 99mTc tin colloid to drink. Drug serum levels were measured on all patients at initial presentation and at follow-up. We observed markedly prolonged gastric emptying half-times and severe hypomotility at initial presentation compared with follow-up in the vast majority of patients, except for a small group of patients with phenytoin poisoning. Twelve patients had gastric emptying half-times of over 300 minutes, a further 14 had half-times of over 200 minutes and 21 others had half-times of over 120 minutes. Poisoning is associated with hypomotility and a marked delay in gastric emptying that could influence the clinical course and patient management. These abnormalities may not be due to a direct effect of the ingested drug and factors such as stress may play a role.

Position paper: Ipecac syrup

Syrup of ipecac should not be administered routinely in the management of poisoned patients. In experimental studies the amount of marker removed by ipecac was highly variable and diminished with time. There is no evidence from clinical studies that ipecac improves the outcome of poisoned patients and its routine administration in the emergency department should be abandoned. There are insufficient data to support or exclude ipecac administration soon after poison ingestion. Ipecac may delay the administration or reduce the effectiveness of activated charcoal, oral antidotes, and whole bowel irrigation. Ipecac should not be administered to a patient who has a decreased level or impending loss of consciousness or who has ingested a corrosive substance or hydrocarbon with high aspiration potential. A review of the literature since the preparation of the 1997 Ipecac Syrup Position Statement revealed no new evidence that would require a revision of the conclusions of that Statement.

Poison treatment in the home. American Academy of Pediatrics Committee on Injury, Violence, and Poison Prevention

The ingestion of a potentially poisonous substance by a young child is a common event, with the American Association of Poison Control Centers reporting approximately 1.2 million such events in the United States in 2001. The American Academy of Pediatrics (AAP) has long concerned itself with this issue and has made poison prevention an integral component of its injury prevention initiatives. A key AAP recommendation has been to keep a 1-oz bottle of syrup of ipecac in the home to be used only on the advice of a physician or poison control center. Recently, there has been interest regarding activated charcoal in the home as a poison treatment strategy. After reviewing the evidence, the AAP believes that ipecac should no longer be used routinely as a home treatment strategy, that existing ipecac in the home should be disposed of safely, and that it is premature to recommend the administration of activated charcoal in the home. The first action for a caregiver of a child who may have ingested a toxic substance is to consult with the local poison control center.

Single-dose oral activated charcoal in the treatment of the self-poisoned patient: a prospective, randomized, controlled trial

Oral activated charcoal (OAC) is a universally accepted treatment of the overdose patient. Although the benefits of OAC have been suggested, there are no conclusive clinical data indicating that OAC affects outcome in overdose patients. This study was a prospective, randomized, controlled trial to determine the effects of OAC treatment in the self-poisoned adult patient. Adult patients presenting to the emergency department (ED) with a history of oral overdose were assigned to treatment with OAC (50 g) or supportive care only on an even-odd day protocol. Patients did not undergo gastric evacuation procedures in the ED. The outcome measures were clinical deterioration, length of stay in the ED or hospital, and complication rate. Over a 24-month period, 1479 patients were entered into the study. There were no significant differences in outcome parameters between the OAC treatment group and controls when comparing the length of intubation time, length of hospital stay, and the complication rates associated with the overdose. There was a higher incidence of vomiting and longer length of ED stay associated with OAC treatment. The results of this study indicated that oral drug overdose patients do not require gastric evacuation or charcoal administration. OAC provided no additional benefit to supportive care alone, was associated with a higher incidence of vomiting and a longer length of ED stay, and did not improve clinical outcome.

Effect of ethanol and pH on the adsorption of acetaminophen (paracetamol) to high surface activated charcoal, in vitro studies

BACKGROUND

Paracetamol (acetaminophen) intoxication often in combination with ethanol, is seen commonly in overdose cases. Doses of several grams might be close to the maximum adsorption capacity of the standard treatment dose (50g) of activated charcoal. The aim of this study was to determine the maximum adsorption capacity for paracetamol for two types of high surface-activated charcoal [Carbomix and Norit Ready-To-Use (not yet registered trademark in Denmark) both from Norit Cosmara, Amersfoort, The Netherlands] in simulated in vivo environments: At pH 1.2 (gastric environment), at pH 7.2 (intestinal environment), and with and without 10% ethanol.

METHODS

Activated charcoal, at both gastric or intestinal pHs, and paracetamol were mixed, resulting in activated charcoal-paracetamol ratios from 10:] to 1:1. In trials with ethanol, some of the gastric or intestinal fluid was replaced with an equivalent volume of ethanol, resulting in an ethanol concentration of 10% v/v. After incubation, the concentration of unabsorbed paracetamol was analyzed by high-performance liquid chromatography. The maximum adsorption capacity of paracetamol to activated charcoal was calculated as mg paracetamol adsorbed/g activated charcoal, using Langmuir's isotherm.

RESULTS

Carbomix [95% confidence limits are shown in square brackets]: 623.7 [612.8;634.5] mg paracetamol adsorbed/g activated charcoal (pH 1.2), 626.2 [611.6;640.9] mg paracetamol adsorbed/g activated charcoal (pH 7.2); Norit Ready-To-Use: 693.6 [676.8;710.5] mg paracetamol adsorbed/g activated charcoal (pH 1.2), 722.6 [687.4;757.9] mg paracetamol adsorbed/g activated charcoal (pH 7.2). For experiments with ethanol (10% v/v) the results with Carbomix were 465.7 [449.2;482.2] mg paracetamol adsorbed/g activated charcoal (pH 1.2), 498.6 [481.8;515.6] mg paracetamol adsorbed/g activated charcoal (pH 7.2); with Norit Ready-To-Use: 617.2 [606.6;627.7] mg paracetamol adsorbed/g activated charcoal (pH 1.2), 640.6 [624.9;656.4] mg paracetamol adsorbed/g activated charcoal (pH 7.2).

CONCLUSION

Under conditions simulating immediate treatment with charcoal, a standard dose of 50 g of either of the two tested activated charcoals adsorbed a sufficient amount of paracetamol to be beneficial in the treatment of the majority of overdoses of this drug. For both types of activated charcoal, with or without ethanol, there was no significant difference in the adsorption of paracetamol at pH 1.2 and 7.2. Norit Ready-To-Use had a larger maximum adsorption capacity than Carbomix, and was not as sensitive as Carbomix to environmental changes (pH and ethanol). The presence of 10% ethanol lowered the adsorption capacity of the two tested activated charcoal preparations by an amount that might be clinically relevant in cases of intoxications by high-gram doses.

Extracorporeal therapies for acute intoxications

Intoxications frequently perturb acid-base and electrolyte status, intravascular volume, and renal function. In selected cases, extracorporeal techniques effectively restore homeostasis and augment intoxicant removal. The use of 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, is a new and effective treatment for patients exposed to toxic alcohols. In this section, practical approaches to commonly encountered intoxicants and the use of extracorporeal techniques are critically reviewed.

Describing Adsorption of Paracetamol from Aqueous Solution on Carbons While Utilizing the Most Widespread Isotherm Models—The Impact of Surface Carbonyl and Basic Groups

The 15 most widespread adsorption isotherm equations are applied for describing recently published paracetamol adsorption data from aqueous solutions (pH 7). Twelve adsorption isotherms, measured at 300, 310, and 320 K, on the series of chemically modified carbons D43/1 (Carbo-Tech, Essen, Germany) differing in surface properties (from basic to strongly acidic) but possessing almost the same porosity, are analyzed. The results of fitting theoretical models to experimental data are arranged according to a decrease in the average value of the determination coefficient. From the models studied the best fit is obtained for Weber-Vliet, Dubinin-Astakhov, and the model published by Jossens. The most important conclusion is that at the lowest temperature studied, where the effect of carbon surface composition on adsorption properties is the most strongly marked, the value of paracetamol maximal adsorption decreases as the amount of surface basic groups and carbonyls increases.

The role of activated charcoal and gastric emptying in gastrointestinal decontamination: a state-of-the-art review

Gastrointestinal decontamination has been practiced for hundreds of years; however, only in the past few years have data emerged that demonstrate a clinical benefit in some patients. Because most potentially toxic ingestions involve agents that are not toxic in the quantity consumed, the exact circumstances in which decontamination is beneficial and which methods are most beneficial in those circumstances remain important topics of research. Maximum benefit from decontamination is expected in patients who present soon after the ingestion. Unfortunately, many overdose patients present at least 2 hours after taking a medication, when most of the toxin has been absorbed or has moved well into the intestine, beyond the expected reach of gastrointestinal decontamination. Decontamination probably does not contribute to the outcome of many such patients, especially those without symptoms. However, if absorption has been delayed or gastrointestinal motility has been slowed, activated charcoal may reduce the final amount absorbed. The use of activated charcoal in these cases may be beneficial and is associated with few complications. Therefore, administration of activated charcoal is recommended as soon as possible after emergency department presentation, unless the agent and quantity are known to be nontoxic, the agent is known not to adsorb to activated charcoal, or the delay has been so long that absorption is probably complete. The use of gastric emptying in addition to activated charcoal has generated intense debate. Several large comparative studies have failed to demonstrate a benefit of gastric emptying before activated charcoal. Because complications of such 2-step decontamination include a higher rate of intubation, aspiration, and ICU admission, gastric emptying in addition to activated charcoal cannot be considered the routine approach to patients. However, there are several infrequent circumstances in which the data are inadequate to accurately assess the potential benefit of gastric emptying in addition to activated charcoal: symptomatic patients presenting in the first hour after ingestion, symptomatic patients who have ingested agents that slow gastrointestinal motility, patients taking sustained release medications, and those taking massive or life-threatening amounts of medication. These circumstances represent only a small subset of ingestions. In the absence of convincing data about benefit or lack of benefit of gastric emptying for these patients, individual physicians must act on a personal valuation: Is it better to use a treatment that might have some benefit but definitely has some risk or not to use a treatment that has any risk unless there is proven benefit?

Interventions for paracetamol (acetaminophen) overdoses

BACKGROUND

Self-poisoning with paracetamol (acetaminophen) is a common cause of hepatotoxicity in the Western World. Interventions for paracetamol poisoning encompass inhibition of absorption, removal from the vascular system, antidotes, and liver transplantation.

OBJECTIVES

The objective was to assess the beneficial and harmful effects of interventions or combination of interventions for paracetamol overdose.

SEARCH STRATEGY

The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Library, MEDLINE, EMBASE, and text searches were combined (until July 2001).

SELECTION CRITERIA

Randomised clinical trials (RCTs) and observational studies as well as human volunteer randomised trials were included. The studies could be unpublished or published as an article, an abstract, or a letter and no language limitations were applied.

DATA COLLECTION AND ANALYSIS

All the analyses were performed according to the intention to treat. The methodological quality of the included trials was evaluated by components of methodological quality.

MAIN RESULTS

Nine RCTs (all small and of low methodological quality), one quasi-randomised trials, 37 observational studies, and nine randomised trials including human volunteers were identified. It was impossible to perform meta-analyses including more than two RCTs. Activated charcoal, gastric lavage, and ipecacuanha are able to reduce the absorption of paracetamol but the clinical benefit is unclear. Of these, activated charcoal seems to have the best risk-benefit ratio. N-acetylcysteine seems preferable to placebo/supportive treatment (relative risk of mortality in patients with fulminant hepatic failure = 0.65; 95% confidence interval 0.43 to 0.99), dimercaprol, and cysteamine, but N-acetylcysteine's superiority to methionine is unproven. It is not clear which N-acetylcysteine treatment protocol offers the best efficacy. No evidence supports haemoperfusion or cimetidine for paracetamol overdose. Liver transplantation has the potential to be life saving in fulminant hepatic failure, but further refinement of selection criteria for liver transplantation and evaluation of the long-term outcome are required.

REVIEWER'S CONCLUSIONS

This systematic Review has highlighted a paucity of RCTs on interventions for paracetamol overdose. Activated charcoal seems the best choice to reduce paracetamol absorption. N-acetylcysteine should be given to patients with paracetamol overdose. No N-acetylcysteine regime has been shown to be more effective than any other. It is a delicate balance when to proceed to liver transplantation, which may be life saving in patients with a poor prognosis. Interventions for paracetamol overdose need assessment in high-quality, multi-centre RCTs.

Past, present, and future role of ipecac syrup

Historically, ipecac syrup has played a principal role in the management of acute poisonings and overdoses. Presently, its role largely has been relegated to prompt decontamination of acute childhood poisonings for which emesis is not contraindicated. However, even this specific and limited role has undergone rigorous re-evaluation, and many toxicologists have discouraged against its use in any circumstance. This article reviews the history, scientific literature, and public health implications of ipecac syrup that support its present clinical application.

The first line of response for people who self-poison: exploring the options for gut decontamination

The trend for increasing numbers of self-poisoning incidents has been noted and a variety of policy initiatives have been launched. Nurses, particularly in emergency room environments occupy a pivotal place in the chain of response to such acts. Any such response needs to be firmly rooted in evidence-based practice yet the initial management of self-poisoning often involves a consideration of procedures, the application of which can vary enormously. This paper offers some contextual information prior to a critical perspective of management modes, namely emesis, lavage, the use of activated charcoal and whole bowel irrigation. A comparison of the relative advantages and disadvantages of each mode precedes suggestions for nursing practice.

Effect of activated charcoal alone or given after gastric lavage in reducing the absorption of diazepam, ibuprofen and citalopram

AIMS

The efficacy of activated charcoal alone, and gastric lavage followed by charcoal in reducing the absorption of diazepam, ibuprofen and citalopram was studied in healthy volunteers.

METHODS

In a randomized cross-over study with three phases, nine healthy volunteers were administered single oral doses of 5 mg diazepam, 400 mg ibuprofen and 20 mg citalopram, taken simultaneously after an overnight fast. Thirty minutes later, the subjects were assigned to one of the following treatments: 200 ml water (control), 25 g activated charcoal as a suspension in 200 ml water or gastric lavage followed by 25 g charcoal in suspension given through the lavage tube. Plasma concentrations of diazepam, ibuprofen and citalopram were determined up to 10 h.

RESULTS

The AUC(0,10 h) of diazepam was reduced by 27% (P<0.05) by both charcoal alone and charcoal combined with lavage. The increase in plasma diazepam concentration from 0.5 h onwards was prevented by both interventions (P</=0.05), whereas the Cmax of diazepam was not significantly affected by either treatment. The AUC(0, 10 h) of ibuprofen was reduced by 49% (P<0.05) after the combination treatment and by 30% (P<0.05) after charcoal alone, but there was no significant difference between these two treatments. Both charcoal alone and the combination treatment were equally effective in preventing the increase in plasma ibuprofen from 0.5 h onwards (P<0.01). The Cmax of ibuprofen was reduced by 45% (P<0.05) and by 21% (P=NS), respectively. The AUC(0,10 h) of citalopram was reduced by 51% (P<0.05) after both charcoal alone and charcoal combined with lavage, and the Cmax by 52% (P<0.05) and 54% (P<0.05), respectively. The increase in plasma citalopram concentration from 0.5 h onwards was reduced by about 50% (P<0.01) by both interventions.

CONCLUSIONS

Activated charcoal alone and charcoal combined with lavage showed similar efficacy in preventing the absorption of diazepam, ibuprofen and citalopram. These results suggest that gastric lavage needs not be routinely performed before administration of charcoal.

Prospective single blinded randomised controlled trial of two orally administered activated charcoal preparations

OBJECTIVES

To compare two activated charcoal preparations (Carbomix and Actidose-Aqua) in terms of amount ingested and incidence of vomiting after ingestion.

METHODS

Single blinded prospective randomised controlled trial.

RESULTS

The mean amount of charcoal ingested was Carbomix 26.5 g, Actidose-Aqua 19.5 g. The mean difference was 7 g (95% confidence interval (CI) 1.5 to 12.4 g). The incidence of vomiting was for the Carbomix 6% and the Actidose-Aqua 8%. The mean difference in vomiting was 2% (95% CI -0.8 to 4.8)

CONCLUSIONS

Carbomix administration results in an increased amount of activated charcoal ingested after oral administration. Rates of vomiting after activated charcoal administration were low when compared with previously reported rates.

A prospective study of acute poisonings in Finnish hospital patients

1. We have carried out a prospective study of all adult patients presenting with acute poisoning during one month to the Helsinki University Central Hospital (Meilahti Hospital). 2. Two hundred and twenty-six cases of acute poisoning (113 males and 113 females) presented to the emergency department. Most cases in both men (66%) and women (67%) involved alcohol. As to drugs, psychotropic agents predominated in both men and women. The frequency of patient presentation peaked between 7 p.m. and 9 p.m. and was lowest between 8 a.m. and 10 a.m. In most cases, the delay from ingestion of the poison to presentation was longer than 4 h. 3. The clinical status of the patients on arrival was generally good; more than half (55%) of them were fully awake. Serious symptoms (e.g. unconsciousness, insufficient respiration necessitating intubation, aspiration, convulsions or hypotension) occurred in 15% of the presentations. There were no fatalities. 4. One hundred and thirty-five patients (60%) received at least one 50-g dose of activated charcoal. However, charcoal was given in 86% of the cases of drug poisoning. Gastric lavage was performed in 112 cases (50%), and 106 cases (47%) involved both gastric lavage and administration of charcoal. Twenty-one patients received antidotes (flumazenil, calcium gluconate or naloxone) and three patients were hemodialysed. 5. Of the 226 cases, 142 (63%) were managed solely in the emergency department. Of the 84 cases admitted to the hospital, eight had to be managed in the intensive care unit. Almost all patients (94%) were discharged within 24 h. 6. In this survey on 226 consecutive cases of acute poisoning, about two-thirds of the cases involved alcohol, while the most common drugs taken were psychotropic agents. The poisoning was mild in the great majority of the cases. Activated charcoal was generally administered in all but trivial cases of drug poisoning.

Position statement: single-dose activated charcoal. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists

In preparing this Position Statement, all relevant scientific literature was identified and reviewed critically by acknowledged experts using agreed criteria. Well-conducted clinical and experimental studies were given precedence over anecdotal case reports and abstracts were not usually considered. A draft Position Statement was then produced and subjected to detailed peer review by an international group of clinical toxicologists chosen by the American Academy of Clinical Toxicology and the European Association of Poisons Centres and Clinical Toxicologists. The Position Statement went through multiple drafts before being approved by the boards of the two societies and being endorsed by other societies. The Position Statement includes a summary statement for ease of use and is supported by detailed documentation which describes the scientific evidence on which the Statement is based. Single-dose activated charcoal should not be administered routinely in the management of poisoned patients. Based on volunteer studies, the effectiveness of activated charcoal decreases with time; the greatest benefit is within 1 hour of ingestion. The administration of activated charcoal may be considered if a patient has ingested a potentially toxic amount of a poison (which is known to be adsorbed to charcoal) up to 1 hour previously; there are insufficient data to support or exclude its use after 1 hour of ingestion. There is no evidence that the administration of activated charcoal improves clinical outcome. Unless a patient has an intact or protected airway, the administration of charcoal is contraindicated.

Position statement: ipecac syrup. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists

In preparing this Position Statement, all relevant scientific literature was identified and reviewed critically by acknowledged experts using agreed criteria. Well-conducted clinical and experimental studies were given precedence over anecdotal case reports and abstracts were not usually considered. A draft Position Statement was then produced and subjected to detailed peer review by an international group of clinical toxicologists chosen by the American Academy of Clinical Toxicology and the European Association of Poisons Centres and Clinical Toxicologists. The Position Statement went through multiple drafts before being approved by the boards of the two societies and being endorsed by other societies. The Position Statement includes a summary statement for ease of use and is supported by detailed documentation which describes the scientific evidence on which the Statement is based. Syrup of ipecac should not be administered routinely in the management of poisoned patients. In experimental studies the amount of marker removed by ipecac was highly variable and diminished with time. There is no evidence from clinical studies that ipecac improves the outcome of poisoned patients and its routine administration in the emergency department should be abandoned. There are insufficient data to support or exclude ipecac administration soon after poison ingestion. Ipecac may delay the administration or reduce the effectiveness of activated charcoal, oral antidotes, and whole bowel irrigation. Ipecac should not be administered to a patient who has a decreased level or impending loss of consciousness or who has ingested a corrosive substance or hydrocarbon with high aspiration potential.

Efficacy of ipecac during the first hour after drug ingestion in human volunteers

OBJECTIVE

To determine the decrease of drug absorption when syrup of ipecac is administered at various times within one hour of drug ingestion.

METHODS

Ten healthy human volunteers were recruited for a four-limbed randomized crossover study. The three experimental limbs consisted of administration of 30 mL syrup of ipecac, at 5, 30, or 60 minutes after ingestion of 3900 mg acetaminophen as 12 x 325 mg tablets with 250 mL room temperature water. The fourth limb served as control. Blood samples were drawn at 0, 0.5, 1.0, 2.0, 3.0, 4.0, 6.0, and 8.0 hours after analgesic ingestion for serum acetaminophen concentration determination by high-performance liquid chromatography. Repeated measures ANOVA and Tukey's HSD tests were used for group comparisons.

RESULTS

The area under the serum concentration vs time curve was (mean +/- SD) 206 +/- 48, 67 +/- 37, 183 +/- 78, and 162 +/- 47 mg/L for control, 5, 30, and 60 minutes, respectively. This corresponds to decreases in bioavailability of 67, 11, and 21%. Only the 5-minute group differed significantly from control (p < 0.05). Sedation was observed as a significant adverse effect of ipecac administration.

CONCLUSIONS

Our data do not support benefit from ipecac administration at 30 minutes and beyond. Our data suggest that benefit is lost at some point between 5 and 30 minutes. The sedative effect of ipecac may confound the observation of patients who have ingested sedative hypnotic agents.

Prevention of amlodipine absorption by activated charcoal: effect of delay in charcoal administration

AIMS

The purpose of this study was to investigate the effect of activated charcoal on the absorption of amlodipine, with special reference to delayed charcoal administration.

METHODS

Thirty-two healthy volunteers, eight subjects in four parallel groups, ingested 10 mg of amlodipine on an empty stomach. Activated charcoal (25 g in 300 ml of water) was ingested either immediately afterwards or 2 h or 6 h after amlodipine, or amlodipine was ingested with 300 ml of water only (control). Plasma concentrations and the cumulative excretion of amlodipine into urine were measured by GC-MS for 96 h and 72 h, respectively. In addition, adsorption of amlodipine to charcoal was studied in vitro.

RESULTS

Activated charcoal administered immediately after amlodipine reduced the amlodipine AUC(0.96 h) and the 72-h urinary excretion by 99% (P < 0.0005). After a delay of 2 h in charcoal administration the AUC(0.96 h) was reduced by 49% (P = 0.001), but after a delay of 6 h the reduction was 15% only (P = NS). At a charcoal:drug ratio of 5:1, about 90% of amlodipine was adsorbed by charcoal in vitro; at ratios of 10:1 and 20:1, adsorption was practically complete.

CONCLUSIONS

Activated charcoal almost completely prevented amlodipine absorption when administered immediately after amlodipine ingestion. Charcoal also markedly reduced amlodipine absorption when given 2 h after amlodipine; in amlodipine overdose, administration of charcoal may be beneficial even later. We conclude that administration of activated charcoal is the method of choice to prevent absorption of amlodipine in amlodipine overdose.

Prehospital use of activated charcoal: a pilot study

Activated charcoal (AC) is most effective when administered soon after the ingestion of certain substances. Delays are recognized to occur at times in the administration of AC after arrival of poisoned patients in the emergency department (ED). In addition, it has been recognized that these delays may be avoided if AC administration is begun in selected patients by paramedics while en route to the ED. We present a pilot study evaluating the administration of AC to poisoned patients in the ambulance prior to arrival in the ED. We performed a retrospective review of Emergency Medical System (EMS) run sheets and ED records of poisoned patients during a 6-month period from two area hospitals. Cases were identified that met criteria for the prehospital administration of AC. Cases were divided into two groups: those who received prehospital AC, and those who did not. Groups were compared for ambulance transport time, time from first paramedic contact to AC administration, and whether AC was tolerated by the patient. A total of 14 patients received prehospital AC (group 1). This group was compared to 22 cases that would have qualified under County protocol to receive prehospital AC, but for whatever reason did not (group 2). Group 2 patients all received AC after arriving in the ED. Average ambulance transport times did not statistically differ among groups. The average time from first encounter with paramedics to administration of AC was 5.0 minutes when AC administration was given in the ambulance as compared to 51.4 minutes when delayed until arrival in the ED. Tolerance was similar among the groups. The time to initiate AC administration may be significantly shortened when begun by prehospital personnel. All EMS should consider including AC in protocols addressing the prehospital management of certain poisoned patients.