Comparison of three methods of gut decontamination in tricyclic antidepressant overdose

Fundaments of Toxicology-Approach to the Poisoned Patient

Management of the poisoned patient begins with supportive care, assessment of organ function and dysfunction, and consideration of known or suspected poisons. The possibility of multiple ingestions should be considered with intentional exposures or suicide attempts. Enteric decontamination involves treatment to prevent the absorption of toxins from the gastrointestinal system and includes the use of activated charcoal. Poisoned patients may benefit from the use if antidotes are available, or enhanced elimination as with salicylate ion trapping during urinary alkalinization. The use of intravenous lipid therapy is of clinical benefit in poisoning from bupivacaine, amitriptyline, and bupropion. Hemodialysis is the most inexpensive, widely available, and most commonly used method of extracorporeal drug removal in the treatment of poisoning. Chelators with different chemical properties can bind toxic metals, providing an essential mechanism for detoxification, and may be used in combination with extracorporeal therapies such as DFO with HD for aluminum or iron, and DMSA or DMPS with HD to treat arsenic or mercury intoxication. The use of displacers with hemodialysis can be considered to augment clearance of protein-bound toxins.

First aid interventions by laypeople for acute oral poisoning

BACKGROUND

Oral poisoning is a major cause of mortality and disability worldwide, with estimates of over 100,000 deaths due to unintentional poisoning each year and an overrepresentation of children below five years of age. Any effective intervention that laypeople can apply to limit or delay uptake or to evacuate, dilute or neutralize the poison before professional help arrives may limit toxicity and save lives.

OBJECTIVES

To assess the effects of pre-hospital interventions (alone or in combination) for treating acute oral poisoning, available to and feasible for laypeople before the arrival of professional help.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, ISI Web of Science, International Pharmaceutical Abstracts, and three clinical trials registries to 11 May 2017, and we also carried out reference checking and citation searching.

SELECTION CRITERIA

We included randomized controlled trials comparing interventions (alone or in combination) that are feasible in a pre-hospital setting for treating acute oral poisoning patients, including but potentially not limited to activated charcoal (AC), emetics, cathartics, diluents, neutralizing agents and body positioning.

DATA COLLECTION AND ANALYSIS

Two reviewers independently performed study selection, data collection and assessment. Primary outcomes of this review were incidence of mortality and adverse events, plus incidence and severity of symptoms of poisoning. Secondary outcomes were duration of symptoms of poisoning, drug absorption, and incidence of hospitalization and ICU admission.

MAIN RESULTS

We included 24 trials involving 7099 participants. Using the Cochrane 'Risk of bias' tool, we assessed no study as being at low risk of bias for all domains. Many studies were poorly reported, so the risk of selection and detection biases were often unclear. Most studies reported important outcomes incompletely, and we judged them to be at high risk of reporting bias.All but one study enrolled oral poisoning patients in an emergency department; the remaining study was conducted in a pre-hospital setting. Fourteen studies included multiple toxic syndromes or did not specify, while the other studies specifically investigated paracetamol (2 studies), carbamazepine (2 studies), tricyclic antidepressant (2 studies), yellow oleander (2 studies), benzodiazepine (1 study), or toxic berry intoxication (1 study). Eighteen trials investigated the effects of activated charcoal (AC), administered as a single dose (SDAC) or in multiple doses (MDAC), alone or in combination with other first aid interventions (a cathartic) and/or hospital treatments. Six studies investigated syrup of ipecac plus other first aid interventions (SDAC + cathartic) versus ipecac alone. The collected evidence was mostly of low to very low certainty, often downgraded for indirectness, risk of bias or imprecision due to low numbers of events.First aid interventions that limit or delay the absorption of the poison in the bodyWe are uncertain about the effect of SDAC compared to no intervention on the incidence of adverse events in general (zero events in both treatment groups; 1 study, 451 participants) or vomiting specifically (Peto odds ratio (OR) 4.17, 95% confidence interval (CI) 0.30 to 57.26, 1 study, 25 participants), ICU admission (Peto OR 7.77, 95% CI 0.15 to 391.93, 1 study, 451 participants) and clinical deterioration (zero events in both treatment groups; 1 study, 451 participants) in participants with mixed types or paracetamol poisoning, as all evidence for these outcomes was of very low certainty. No studies assessed SDAC for mortality, duration of symptoms, drug absorption or hospitalization.Only one study compared SDAC to syrup of ipecac in participants with mixed types of poisoning, providing very low-certainty evidence. Therefore we are uncertain about the effects on Glasgow Coma Scale scores (mean difference (MD) -0.15, 95% CI -0.43 to 0.13, 1 study, 34 participants) or incidence of adverse events (risk ratio (RR) 1.24, 95% CI 0.26 to 5.83, 1 study, 34 participants). No information was available concerning mortality, duration of symptoms, drug absorption, hospitalization or ICU admission.This review also considered the added value of SDAC or MDAC to hospital interventions, which mostly included gastric lavage. No included studies investigated the use of body positioning in oral poisoning patients.First aid interventions that evacuate the poison from the gastrointestinal tractWe found one study comparing ipecac versus no intervention in toxic berry ingestion in a pre-hospital setting. Low-certainty evidence suggests there may be an increase in the incidence of adverse events, but the study did not report incidence of mortality, incidence or duration of symptoms of poisoning, drug absorption, hospitalization or ICU admission (103 participants).In addition, we also considered the added value of syrup of ipecac to SDAC plus a cathartic and the added value of a cathartic to SDAC.No studies used cathartics as an individual intervention.First aid interventions that neutralize or dilute the poison No included studies investigated the neutralization or dilution of the poison in oral poisoning patients.The review also considered combinations of different first aid interventions.

AUTHORS' CONCLUSIONS

The studies included in this review provided mostly low- or very low-certainty evidence about the use of first aid interventions for acute oral poisoning. A key limitation was the fact that only one included study actually took place in a pre-hospital setting, which undermines our confidence in the applicability of these results to this setting. Thus, the amount of evidence collected was insufficient to draw any conclusions.

Lethal Tricyclic Antidepressant Overdose

Tricyclic antidepressant remains widely prescribed despite its dangerous cardiovascular and neurological effects in overdosed patients. We present a case of lethal dothiepin overdose and discuss the major complications and its management strategies.

Analysis of Gastric Lavage Reported to a Statewide Poison Control System

BACKGROUND

As decontamination trends have evolved, gastric lavage (GL) has become a rare procedure. The current information regarding use, outcomes, and complications of GL could help refine indications for this invasive procedure.

OBJECTIVES

We sought to determine case type, location, and complications of GL cases reported to a statewide poison control system.

METHODS

This is a retrospective review of the California Poison Control System (CPCS) records from 2009 to 2012. Specific substances ingested, results and complications of GL, referring hospital ZIP codes, and outcomes were examined.

RESULTS

Nine hundred twenty-three patients who underwent GL were included in the final analysis, ranging in age from 9 months to 88 years. There were 381 single and 540 multiple substance ingestions, with pill fragment return in 27%. Five hundred thirty-six GLs were performed with CPCS recommendation, while 387 were performed without. Complications were reported for 20 cases. There were 5 deaths, all after multiple ingestions. Among survivors, 37% were released from the emergency department, 13% were admitted to hospital wards, and 48% were admitted to intensive care units. The most commonly ingested substances were nontricyclic antidepressant psychotropics (n = 313), benzodiazepines (n = 233), acetaminophen (n = 191), nonsteroidal anti-inflammatory drugs (n = 107), diphenhydramine (n = 70), tricyclic antidepressants (n = 45), aspirin (n = 45), lithium (n = 36), and antifreeze (n = 10). The geographic distribution was clustered near regions of high population density, with a few exceptions.

CONCLUSIONS

Toxic agents for which GL was performed reflected a broad spectrum of potential hazards, some of which are not life-threatening or have effective treatments. Continuing emergency physician and poison center staff education is required to assist in patient selection.

Extracorporeal treatment for tricyclic antidepressant poisoning: recommendations from the EXTRIP Workgroup

The Extracorporeal Treatments In Poisoning (EXTRIP) workgroup was formed to provide recommendations on the use of extracorporeal treatments (ECTR) in poisoning. Here, the workgroup presents its results for tricyclic antidepressants (TCAs). After an extensive literature search, using a predefined methodology, the subgroup responsible for this poison reviewed the articles, extracted the data, summarized findings, and proposed structured voting statements following a predetermined format. A two-round modified Delphi method was chosen to reach a consensus on voting statements and RAND/UCLA Appropriateness Method to quantify disagreement. Blinded votes were compiled, returned, and discussed in person at a meeting. A second vote determined the final recommendations. Seventy-seven articles met inclusion criteria. Only case reports, case series, and one poor-quality observational study were identified yielding a very low quality of evidence for all recommendations. Data on 108 patients, including 12 fatalities, were abstracted. The workgroup concluded that TCAs are not dialyzable and made the following recommendation: ECTR is not recommended in severe TCA poisoning (1D). The workgroup considers that poisoned patients with TCAs are not likely to have a clinical benefit from extracorporeal removal and recommends it NOT to be used in TCA poisoning.

Amitriptyline, clomipramine, and doxepin adsorption onto sodium polystyrene sulfonate

Purpose of the study

Comparative in vitro studies were carried out to determine the adsorption characteristics of 3 drugs on activated charcoal (AC) and sodium polystyrene sulfonate (SPS). Activated charcoal (AC) has been long used as gastric decontamination agent for tricyclic antidepressants (TCA).

Methods

Solutions containing drugs (amitriptyline, clomipramine, or doxepin) and variable amount of AC or SPS were incubated for 30 minutes.

Results

At pH 1.2 the adsorbent: drug mass ratio varied from 2 : 1 to 40 : 1 for AC, and from 0.4 : 1 to 8 : 1 for SPS. UV–VIS spectrophotometer was used for the determination of free drug concentrations. The qmax of amitriptyline was 0.055 mg/mg AC and 0.574 mg/mg SPS, qmax of clomipramine was 0.053 mg/mg AC and 0.572 mg/mg SPS, and qmax of doxepin was 0.045 mg/mg AC and 0.556 mg/mg SPS. The results of adsorption experiments with SPS revealed higher values for the qmax parameters in comparison with AC.

Conclusion

In vitro gastric decontamination experiments for antidepressant amitriptyline, clomipramine, and doxepin showed that SPS has higher qmax values than the corresponding experiments with AC. Therefore, we suggest SPS is a better gastric decontaminating agent for the management of acute TCA intoxication.

Hemodiafiltration: a novel approach for treating severe amitriptyline intoxication

Tricyclic antidepressant overdose is one of the most common cause of serious drug poisonings. Sometimes amitriptyline intoxication can be difficult to treat with standard treatments. At that case hemodiafiltration (HD) can be an eligible choice. We report a successful treatment of severe case using hemodiafiltration in addition to the supportive measures. Management with gastric lavage, activated charcoal, alkalinization and supportive care is the common approach and not enough for patients in deep coma. We satisfied that HD may have a beneficial role in lethal doses of amitriptyline as an additional therapy.

Rhabdomyolysis as a manifestation of clomipramine poisoning

CONTEXT

Tricyclic antidepressive agents are widely used in suicide attempts and present a variety of deleterious effects. Rhabdomyolysis is a rare complication of such poisoning.

CASE REPORT

A 55-year-old woman ingested 120 pills of 25 mg clomipramine in a suicide attempt two days before admission. After gastric lavage in another emergency department on the day of intake, 80 pills were removed. On admission to our department, she was disoriented, complaining of a dry mouth and tremors at the extremities. An electrocardiogram showed a sinus rhythm with narrow QRS complexes. Laboratory results showed high creatine phosphokinase (CK = 15,094 U/l on admission; normal range = 26 to 140 U/l), hypocalcemia, slightly increased serum transaminases and mild metabolic acidosis. The patient's medical history included depression with previous suicide attempts, obsessive-compulsive disorder, hypothyroidism and osteoporosis. She presented cardiac arrest with pulseless electric activity for seven minutes and afterwards, without sedation, showed continuous side-to-side eye movement. She developed refractory hypotension, with need for vasopressors. Ceftriaxone and clindamycin administration was started because of a hypothesis of bronchoaspiration. The patient remained unresponsive even without sedation, with continuous side-to-side eye movement and a decerebrate posture. She died two months later. Rhabdomyolysis is a very rare complication of poisoning due to tricyclic drugs. It had only previously been described after an overdose of cyclobenzaprine, which has a toxicity profile similar to tricyclic drugs.

CONCLUSIONS

Although arrhythmia is the most important complication, rhabdomyolysis should be investigated in cases of clomipramine poisoning.

Indications for single-dose activated charcoal administration in acute overdose

PURPOSE OF REVIEW

Gastrointestinal decontamination in overdose patients remains a controversial problem in emergency medicine. There has been a significant decrease in the use of single-dose activated charcoal (SDAC) in recent years based on little new evidence and possibly because the overall mortality in overdose patients is low.

RECENT FINDINGS

Human volunteer studies suggest SDAC is effective and this effect occurs for up to 4 h after ingestion, but the magnitude of the reduction in area under the curve (AUC) decreases over time. Two randomized controlled trials including one recent large study did not find SDAC to be beneficial. Pharmacokinetic and pharmacodynamic studies of specific drugs in overdose suggest that for most drugs SDAC decreases drug exposure, but this does not translate to clinical benefit in all cases. The administration of SDAC is a low-risk intervention.

SUMMARY

Although SDAC is unlikely to be beneficial in many overdose patients, for some subgroups with severe poisoning, the benefits will outweigh the low risk of administration. The use of SDAC should be based on the potential toxicity of the drug ingested and the potential benefit of SDAC balanced against the willingness of the patient to take SDAC and the low risk of administration.

Gastrointestinal decontamination in the acutely poisoned patient

Objective

To define the role of gastrointestinal (GI) decontamination of the poisoned patient.

Data Sources

A computer-based PubMed/MEDLINE search of the literature on GI decontamination in the poisoned patient with cross referencing of sources.

Study Selection and Data Extraction

Clinical, animal and in vitro studies were reviewed for clinical relevance to GI decontamination of the poisoned patient.

Data Synthesis

The literature suggests that previously, widely used, aggressive approaches including the use of ipecac syrup, gastric lavage, and cathartics are now rarely recommended. Whole bowel irrigation is still often recommended for slow-release drugs, metals, and patients who "pack" or "stuff" foreign bodies filled with drugs of abuse, but with little quality data to support it. Activated charcoal (AC), single or multiple doses, was also a previous mainstay of GI decontamination, but the utility of AC is now recognized to be limited and more time dependent than previously practiced. These recommendations have resulted in several treatment guidelines that are mostly based on retrospective analysis, animal studies or small case series, and rarely based on randomized clinical trials.

Conclusions

The current literature supports limited use of GI decontamination of the poisoned patient.

Brugada-like ECG pattern induced by tricyclic antidepressants

We present the case report of a 57-year-old woman with severe monointoxication with dosulepine (Prothiaden) who developed a Brugada-like electrocardiographic pattern. In tricyclic antidepressants (TCAs) poisoning the Brugada-like pattern on electrocardiogram is a characteristic albeit rare manifestation of the frequently occurring conduction abnormalities in the myocardium and its recognition is imperative as it is associated with a higher degree of morbidity and mortality. An overview of the literature is given and recommendations concerning treatment of TCA-induced arrhythmias are provided. After successful treatment, the electrocardiogram in the patient normalized. However, 4 days after intoxication, the ajmaline test was positive (pharmacological induction of a type I Brugada-like pattern), but a subsequent one, repeated after 11 days, was reportedly normal, probably because of the slow clearance of dosulepine. This raises questions about the specificity of ajmaline testing for Brugada syndrome in patients taking dosulepine and perhaps other TCAs and neuroleptic agents.

Drugs and pharmaceuticals: management of intoxication and antidotes

The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of decontamination and enhanced elimination, and the use of specific antidotes where warranted. Data supporting antidotes effectiveness vary considerably. Clinicians are encouraged to utilize consultation with regional poison centers or those with toxicology training to assist with diagnosis, management, and administration of antidotes, particularly in unfamiliar cases.

Clinical cases in acute intoxication

Over 2.5 million accidental and intentional drug-related poisonings are reported annually in the United States. Early diagnosis and management of patients who present with acute intoxication can significantly reduce both morbidity and mortality. The initial evaluation of patients with suspected or proven intoxications should focus on hemodynamic stability, mental status, and respiratory function. However, early recognition of toxic ingestion is paramount to implementing life-saving treatments. Important historical clues are often found in a social history that considers intravenous drug use, alcohol use, and any access or exposure to illicit substances. A patient's medication list should also be scrutinized for psychoactive or sedative medications, such as tricyclic antidepressants or opioids. In this article we present case-based discussions of the specific diagnosis and management of 5 commonly occurring acute intoxication syndromes.

Tricyclic antidepressant poisoning: an evidence-based consensus guideline for out-of-hospital management

A review of U.S. poison center data for 2004 showed over 12,000 exposures to tricyclic antidepressants (TCAs). A guideline that determines the conditions for emergency department referral and prehospital care could potentially optimize patient outcome, avoid unnecessary emergency department visits, reduce healthcare costs, and reduce life disruption for patients and caregivers. An evidence-based expert consensus process was used to create the guideline. Relevant articles were abstracted by a trained physician researcher. The first draft of the guideline was created by the lead author. The entire panel discussed and refined the guideline before distribution to secondary reviewers for comment. The panel then made changes based on the secondary review comments. The objective of this guideline is to assist poison center personnel in the appropriate prehospital triage and management of patients with suspected ingestions of TCAs by 1) describing the manner in which an ingestion of a TCA might be managed, 2) identifying the key decision elements in managing cases of TCA ingestion, 3) providing clear and practical recommendations that reflect the current state of knowledge, and 4) identifying needs for research. This guideline applies to ingestion of TCAs alone. Co-ingestion of additional substances could require different referral and management recommendations depending on their combined toxicities. This guideline is based on the assessment of current scientific and clinical information. The panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and the health professionals providing care, considering all the circumstances involved. This guideline does not substitute for clinical judgment. Recommendations are in chronological order of likely clinical use. The grade of recommendation is in parentheses. 1) Patients with suspected self-harm or who are the victims of malicious administration of a TCA should be referred to an emergency department immediately (Grade D). 2) Patients with acute TCA ingestions who are less than 6 years of age and other patients without evidence of self-harm should have further evaluation including standard history taking and determination of the presence of co-ingestants (especially other psychopharmaceutical agents) and underlying exacerbating conditions, such as convulsions or cardiac arrhythmias. Ingestion of a TCA in combination with other drugs might warrant referral to an emergency department. The ingestion of a TCA by a patient with significant underlying cardiovascular or neurological disease should cause referral to an emergency department at a lower dose than for other individuals. Because of the potential severity of TCA poisoning, transportation by EMS, with close monitoring of clinical status and vital signs en route, should be considered (Grade D). 3) Patients who are symptomatic (e.g., weak, drowsy, dizzy, tremulous, palpitations) after a TCA ingestion should be referred to an emergency department (Grade B). 4) Ingestion of either of the following amounts (whichever is lower) would warrant consideration of referral to an emergency department: an amount that exceeds the usual maximum single therapeutic dose or an amount equal to or greater than the lowest reported toxic dose. For all TCAs except desipramine, nortriptyline, trimipramine, and protriptyline, this dose is >5 mg/kg. For despiramine it is >2.5 mg/kg; for nortriptyline it is >2.5 mg/kg; for trimipramine it is >2.5 mg/kg; and for protriptyline it is >1 mg/kg. This recommendation applies to both patients who are naïve to the specific TCA and to patients currently taking cyclic antidepressants who take extra doses, in which case the extra doses should be added to the daily dose taken and then compared to the threshold dose for referral to an emergency department (Grades B/C). 5) Do not induce emesis (Grade D). 6) The risk-to-benefit ratio of prehospital activated charcoal for gastrointestinal decontamination in TCA poisoning is unknown. Prehospital activated charcoal administration, if available, should only be carried out by health professionals and only if no contraindications are present. Do not delay transportation in order to administer activated charcoal (Grades B/D). 7) For unintentional poisonings, asymptomatic patients are unlikely to develop symptoms if the interval between the ingestion and the initial call to a poison center is greater than 6 hours. These patients do not need referral to an emergency department facility (Grade C). 8) Follow-up calls to determine the outcome for a TCA ingestions ideally should be made within 4 hours of the initial call to a poison center and then at appropriate intervals thereafter based on the clinical judgment of the poison center staff (Grade D). 9) An ECG or rhythm strip, if available, should be checked during the prehospital assessment of a TCA overdose patient. A wide-complex arrhythmia with a QRS duration longer than 100 msec is an indicator that the patient should be immediately stabilized, given sodium bicarbonate if there is a protocol for its use, and transported to an emergency department (Grade B). 10) Symptomatic patients with TCA poisoning might require prehospital interventions, such as intravenous fluids, cardiovascular agents, and respiratory support, in accordance with standard ACLS guidelines (Grade D). 11) Administration of sodium bicarbonate might be beneficial for patients with severe or life-threatening TCA toxicity if there is a prehospital protocol for its use (Grades B/D). 12) For TCA-associated convulsions, benzodiazepines are recommended (Grade D). 13) Flumazenil is not recommended for patients with TCA poisoning (Grade D).

The approach to the patient with an unknown overdose

Toxic overdose can present with various clinical signs and symptoms. These may be the only clues to diagnosis when the cause of toxicity is unknown at the time of initial assessment. The prognosis and clinical course of recovery of a patient poisoned by a specific agent depends largely on the quality of care delivered within the first few hours in the emergency setting. Usually the drug or toxin can be quickly identified by a careful history, a directed physical examination, and commonly available laboratory tests. Once the patient has been stabilized, the physician must consider how to minimize the bioavailability of toxin not yet absorbed, which antidotes (if any) to administer, and if other measures to enhance elimination are necessary.

A randomized clinical trial of activated charcoal for the routine management of oral drug overdose

BACKGROUND

Activated charcoal (AC) is commonly used for the routine management of oral drug overdose.

AIM

To determine whether the routine use of activated charcoal has an effect on patient outcomes.

DESIGN

Randomized controlled unblinded trial.

METHODS

We recruited all adult patients presenting with an oral overdose at The Canberra Hospital, excluding only transfers, late presenters, those who had ingested drugs not adsorbed by activated charcoal or where administration was contraindicated, and very serious ingestions (at the discretion of the admitting physician). Patients were randomized to either activated charcoal or no decontamination.

RESULTS

The trial recruited 327 patients over 16 months. Of 411 presentations, four refused consent, 27 were protocol violations and 53 were excluded from the trial. Only seven were excluded due to the severity of their ingestion. The most common substances ingested were benzodiazepines, paracetamol and selective serotonin reuptake inhibitor antidepressants. More than 80% of patients presented within 4 h following ingestion. There were no differences between AC and no decontamination in terms of length of stay (AC 6.75 h, IQR 4-14 vs. controls 5.5 h, IQR 3-12; p=0.11) or secondary outcomes including vomiting, mortality and intensive care admission.

DISCUSSION

Routine administration of charcoal following oral overdose did not significantly influence length of stay or other patient outcomes following oral drug overdose. There were few adverse events. This does not exclude a role in patients who present shortly after ingestion of highly lethal drugs.

The Management of Tricyclic Antidepressant Poisoning

Although there have been descriptive, uncontrolled clinical reports of removal of tablet debris by gastric lavage, there have been no clinical studies that have demonstrated that this has any impact on outcome in patients with tricyclic antidepressant (TCA) poisoning. There is also the possibility that lavage may increase drug absorption by pushing tablets into the small intestine. Furthermore, gastric lavage in patients with TCA poisoning may induce hypoxia and a tachycardia potentially increasing the risk of severe complications such as arrhythmias and convulsions. In view of the paucity of evidence that gastric lavage removes a significant amount of drug and the risk of complications associated with the procedure, the routine use of gastric lavage in the management of patients with TCA poisoning is not appropriate. Volunteer studies have shown generally that activated charcoal is more likely to reduce drug absorption if it is administered within 1 hour of drug ingestion. In the one volunteer study that looked at later administration of activated charcoal, there was a 37% decrease in plasma concentration associated with administration of activated charcoal at 2 hours post-ingestion. There have been no clinical studies that enable an estimate of the effect of activated charcoal administration on outcome in the management of patients with TCA poisoning. Volunteer studies have shown that multiple-dose activated charcoal increases the elimination of therapeutic doses of amitriptyline and nortriptyline, but not of doxepin or imipramine; however, these studies cannot be directly extrapolated to the management of patients with TCA poisoning. There have been no well designed controlled studies that have assessed the impact of multiple-dose activated charcoal in the management of patients with TCA poisoning. Because of the large volume of distribution of TCAs, it would not be expected that their elimination would be significantly increased by multiple-dose activated charcoal.Haemoperfusion, haemodialysis and the combination of these procedures do not result in significant removal of TCAs and are not recommended in the management of patients with TCA poisoning.

Toxicology in the critically ill patient

Intoxications present in many forms including: known drug overdose or toxic exposure, illicit drug use, suicide attempt, accidental exposure, and chemical or biological terrorism. A high index of suspicion and familiarity with toxidromes can lead to early diagnosis and intervention in critically ill, poisoned patients. Despite a paucity of evidence-based information on the management of intoxicated patients, a rational and systematic approach can be life saving.

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.

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.

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?

The potential role of prehospital administration of activated charcoal

OBJECTIVES

Activated charcoal is now the mainstay of non-specific treatment for self poisoning in accident and emergency (A&E) departments and should be administered within one hour of ingestion of an overdose. This study aimed to investigate if compliance with treatment guidelines may be improved by the prehospital administration of activated charcoal.

METHOD

Ambulance report forms and case notes were reviewed in all patients presenting to A&E by ambulance after self poisoning. Information was gathered using a standardised abstraction form. The times collected were: time of ingestion, time of call to ambulance control, time picked up, time of arrival in A&E and time seen by doctor.

RESULTS

201 patient records were reviewed. Twenty six were excluded because of incomplete data on report forms or case notes. The median time between ingestion and pick up by an ambulance crew was 77 minutes. This compares with a median of 140 minutes for the time to assessment by medical staff. Seventy three patients were picked up by an ambulance within one hour of overdose, only 11 (15%) of these were seen by medical staff within an hour of ingestion. Forty nine of these 73 patients would have been suitable candidates to receive activated charcoal.

CONCLUSIONS

The prehospital administration of charcoal provides an opportunity to comply with international guidelines on reducing the absorption of a potentially fatal overdose. The administration of charcoal results in few side effects provided the patient can adequately protect their airway and ambulance staff could be trained in its use. Further studies would be necessary to investigate if this would effect clinical outcome.

Tricyclic antidepressant overdose: a review

Overdoses of tricyclic antidepressants are among the commonest causes of drug poisoning seen in accident and emergency departments. This review discusses the pharmacokinetics, clinical presentation and treatment of tricyclic overdose.

Antidepressants, old and new. A review of their adverse effects and toxicity in overdose

The newer antidepressants are as efficacious as the older agents in the treatment of depression. They have a side effect profile that is different from the older drugs and are generally better tolerated. Drug-drug interactions do exist with some of these agents and can usually be predicted from knowledge of their metabolism. When taken in overdose as the sole agents they are rarely fatal; seizures, nausea, vomiting, decreased level of consciousness, and tachycardia are common. In combination with other drugs, toxicity can be more severe. The serotonin syndrome can occur with many of these drugs, and the emergency physician must be vigilant in the evaluation of the overdose patient. CAs and older MAOIs are still in use and remain dangerous when taken in overdose. Patients asymptomatic after a period of observation in the ED usually can be discharged after psychiatric evaluation, when it is required.

Activated charcoal as the sole intervention for treatment after childhood poisoning

Childhood poisonings account for approximately two thirds of all human toxic exposures reported annually to the American Association of Poison Control Centers. Activated charcoal (AC) is the mainstay of decontamination in the emergency department setting. This review focuses on six concepts: 1) description of AC and its method of action, 2) evolution of AC in the gastrointestinal decontamination process, 3) prehospital use of AC, 4) superactivated charcoal, 5) multiple-dose AC, and 6) complications of AC administration. The most recent evolving trends in decontamination of the pediatric patient include trends toward earlier decontamination, either in the home or by paramedics in the field. The newer, "super" activated charcoals, with their greater surface area, may improve compliance of oral administration of AC. Finally, guidelines have been set to limit use of multiple-dose activated charcoal regimens to certain pharmaceuticals only, as well as discouraging cathartic use with charcoal dosing.

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.

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.

Potential time savings by prehospital administration of activated charcoal

OBJECTIVE

Activated charcoal (AC) has been proven useful in many toxic ingestions. Theoretically, administration of AC in the prehospital environment could save valuable time in the treatment of patients who have sustained potentially toxic oral ingestions. The purpose of this study was to determine the frequency of prehospital AC administration and to identify time savings that could potentially result from field AC administration.

METHODS

Adult patients with a chief complaint of toxic ingestion who had complete emergency medical services (EMS) and emergency department (ED) records and no medical treatment (gastric emptying, AC administration) prior to EMS arrival were eligible for inclusion. Data obtained from EMS and ED records included time of EMS departure from the scene, time of EMS arrival at the ED, and time of administration of AC in the ED. Since most EMS agencies in this system do not insert gastric tubes, patients requiring gastric tube placement for administration of AC were excluded.

RESULTS

Twenty-nine of 117 (24.8%) adult patients received oral AC with no other intervention. None of the 117 patients received AC in the prehospital setting. The EMS transport time for these patients ranged from 5 to 43 minutes (mean 16.2 +/- 9.7 minutes). The delay from ED arrival to AC administration ranged from 5 to 94 minutes (mean 48.8 +/- 24.1 minutes), and was more than 60 minutes for 14 (48.2%) of the patients. The total time interval from scene departure to ED AC administration ranged from 17 to 111 minutes (mean 65.0 +/- 25.9 minutes).

CONCLUSIONS

In a selected subset of patients who tolerate oral AC, prehospital administration of AC could result in earlier and potentially more efficacious AC therapy. Prospective study of the benefits and feasibility of prehospital AC administration is indicated.