The clinical toxicology of metamfetamine

INTRODUCTION

Metamfetamine is a highly addictive amfetamine analog that acts primarily as a central nervous system (CNS) stimulant. The escalating abuse of this drug in recent years has lead to an increasing burden upon health care providers. An understanding of the drug's toxic effects and their medical treatment is therefore essential for the successful management of patients suffering this form of intoxication.

AIM

The aim of this review is to summarize all main aspects of metamfetamine poisoning including epidemiology, mechanisms of toxicity, toxicokinetics, clinical features, diagnosis, and management.

METHODS

A summary of the literature on metamfetamine was compiled by systematically searching OVID MEDLINE and ISI Web of Science. Further information was obtained from book chapters, relevant news reports, and web material. Epidemiology. Following its use in the Second World War, metamfetamine gained popularity as an illicit drug in Japan and later the United States. Its manufacture and use has now spread to include East and South-East Asia, North America, Mexico, and Australasia, and its world-wide usage, when combined with amfetamine, exceeds that of all other drugs of abuse except cannabis. Mechanisms of toxicity. Metamfetamine acts principally by stimulating the enhanced release of catecholamines from sympathetic nerve terminals, particularly of dopamine in the mesolimbic, mesocortical, and nigrostriatal pathways. The consequent elevation of intra-synaptic monoamines results in an increased activation of central and peripheral α±- and β-adrenergic postsynaptic receptors. This can cause detrimental neuropsychological, cardiovascular, and other systemic effects, and, following long-term abuse, neuronal apoptosis and nerve terminal degeneration. Toxicokinetics. Metamfetamine is rapidly absorbed and well distributed throughout the body, with extensive distribution across high lipid content tissues such as the blood-brain barrier. In humans the major metabolic pathways are aromatic hydroxylation producing 4-hydroxymetamfetamine and N-demethylation to form amfetamine. Metamfetamine is excreted predominantly in the urine and to a lesser extent by sweating and fecal excretion, with reported terminal half-lives ranging from ∼5 to 30 h. Clinical features. The clinical effects of metamfetamine poisoning can vary widely, depending on dose, route, duration, and frequency of use. They are predominantly characteristic of an acute sympathomimetic toxidrome. Common features reported include tachycardia, hypertension, chest pain, various cardiac dysrhythmias, vasculitis, headache, cerebral hemorrhage, hyperthermia, tachypnea, and violent and aggressive behaviour. Management. Emergency stabilization of vital functions and supportive care is essential. Benzodiazepines alone may adequately relieve agitation, hypertension, tachycardia, psychosis, and seizure, though other specific therapies can also be required for sympathomimetic effects and their associated complications.

CONCLUSION

Metamfetamine may cause severe sympathomimetic effects in the intoxicated patient. However, with appropriate, symptom-directed supportive care, patients can be expected to make a full recovery.

Activated charcoal: to give or not to give?

There has been much debate about the use of activated charcoal in patients who have taken overdoses and then present to Emergency Departments. There are clinical trials, research and position statements that have examined the effectiveness of activated charcoal in a number of overdoses of different medications, but there is still a debate surrounding the evidence based practice of administering activated charcoal in patients who have taken a drug overdose due to lack of evidence. This article will examine on the two main guidelines on activated charcoal, one produced by the National Institute for Clinical Excellence and the second produced by American Academy of Clinical Toxicology. It will discuss the methods of administration on activated charcoal, contraindications and the difficulties or challenges in adhering to these guidelines in the clinical setting.

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.

Nicotinic plant poisoning

INTRODUCTION

A wide range of plants contain nicotinic and nicotinic-like alkaloids. Of this diverse group, those that have been reported to cause human poisoning appear to have similar mechanisms of toxicity and presenting patients therefore have comparable toxidromes. This review describes the taxonomy and principal alkaloids of plants that contain nicotinic and nicotinic-like alkaloids, with particular focus on those that are toxic to humans. The toxicokinetics and mechanisms of toxicity of these alkaloids are reviewed and the clinical features and management of poisoning due to these plants are described.

METHODS

This review was compiled by systematically searching OVID MEDLINE and ISI Web of Science. This identified 9,456 papers, excluding duplicates, all of which were screened. Reviewed plants and their principal alkaloids. Plants containing nicotine and nicotine-like alkaloids that have been reported to be poisonous to humans include Conium maculatum, Nicotiana glauca and Nicotiana tabacum, Laburnum anagyroides, and Caulophyllum thalictroides. They contain the toxic alkaloids nicotine, anabasine, cytisine, n-methylcytisine, coniine, n-methylconiine, and gamma-coniceine.

MECHANISMS OF TOXICITY

These alkaloids act agonistically at nicotinic-type acetylcholine (cholinergic) receptors (nAChRs). The nicotinic-type acetylcholine receptor can vary both in its subunit composition and in its distribution within the body (the central and autonomic nervous systems, the neuromuscular junctions, and the adrenal medulla). Agonistic interaction at these variable sites may explain why the alkaloids have diverse effects depending on the administered dose and duration of exposure.

TOXICOKINETICS

Nicotine and nicotine-like alkaloids are absorbed readily across all routes of exposure and are rapidly and widely distributed, readily traversing the blood-brain barrier and the placenta, and are freely distributed in breast milk. Metabolism occurs predominantly in the liver followed by rapid renal elimination.

CLINICAL FEATURES

Following acute exposure, symptoms typically follow a biphasic pattern. The early phase consists of nicotinic cholinergic stimulation resulting in symptoms such as abdominal pain, hypertension, tachycardia, and tremors. The second inhibitory phase is delayed and often heralded by hypotension, bradycardia, and dyspnea, finally leading to coma and respiratory failure.

MANAGEMENT

Supportive care is the mainstay of management with primary emphasis on cardiovascular and respiratory support to ensure recovery.

CONCLUSIONS

Exposure to plants containing nicotine and nicotine-like alkaloids can lead to severe poisoning but, with prompt supportive care, patients should make a full recovery.

The outcome of North American pediatric unintentional mushroom ingestions with various decontamination treatments: an analysis of 14 years of TESS data

The optimum empiric decontamination therapy for unintentional pediatric mushroom ingestion is not known. We sought to determine case outcomes for unintentional mushroom ingestions in children by decontamination therapies utilized. The 1992-2005 American Association of Poison Control Centers Toxic Exposure Surveillance System was queried for cases of unintentional acute mushroom ingestions in children age <6 years. Cases were excluded if outcome was unknown, if exposure was coded as unrelated to the symptoms, or if there was co-ingestion of a non-mycoid substance. The treatment subgroups analyzed were ipecac, single-dose activated charcoal, and no gastric decontamination. 82,330 cases met the inclusion criteria with 22,454 cases excluded. There were 16 cases with major effects and no deaths. There were 57,531 cases in the three treatment subgroups. There was a significantly smaller percentage of cases with moderate or major outcomes in the ipecac subgroup compared to the no decontamination subgroup. There was a significantly greater percentage of cases with moderate or major outcomes in the activated charcoal compared to the no decontamination subgroup. If decontamination therapy is being performed, and this data suggests it may not be necessary, syrup of ipecac could still be considered an effective option.

Salicylate intoxication: a clinical review

Salicylates are widely used and are easily available as over-the-counter medications; thus, they can be readily abused. Although acute toxicity can be readily diagnosed if an ingestion history is provided, both acute and chronic salicylate toxicity often goes unrecognized, with high mortality when the patient is not treated properly. Salicylates should be considered in the differential diagnosis of an adult patient with acid-base abnormalities of uncertain cause, especially when there are concurrent neurologic symptoms. Patients with salicylate toxicity are treated with alkaline diuresis and sometimes dialysis. The prognosis depends on prompt recognition and treatment. Delayed diagnosis results in increased morbidity and mortality, particularly in the elderly.

Management of the critically poisoned patient

BACKGROUND

Clinicians are often challenged to manage critically ill poison patients. The clinical effects encountered in poisoned patients are dependent on numerous variables, such as the dose, the length of exposure time, and the pre-existing health of the patient. The goal of this article is to introduce the basic concepts for evaluation of poisoned patients and review the appropriate management of such patients based on the currently available literature.

METHODS

An unsystematic review of the medical literature was performed and articles pertaining to human poisoning were obtained. The literature selected was based on the preference and clinical expertise of authors.

DISCUSSION

If a poisoning is recognized early and appropriate testing and supportive care is initiated rapidly, the majority of patient outcomes will be good. Judicious use of antidotes should be practiced and clinicians should clearly understand the indications and contraindications of antidotes prior to administration.

Amlodipine toxicity in children less than 6 years of age: a dose-response analysis using national poison data system data

BACKGROUND

Amlodipine is a long-acting calcium channel blocker capable of producing hypotension and dysrhythmia in overdose. The toxic doses of amlodipine in children are unclear.

OBJECTIVES

The purposes of this study were to describe amlodipine poisoning in children and to determine whether a dose-response relationship could be detected in this population using standardized call data from United States (US) poison centers.

PATIENTS AND METHODS

1251 amlodipine-only ingestions in children < 6 years of age were reviewed. Cases with doses coded as "Exact" or "Estimated" and with dose, age, and medical outcome were analyzed (n = 678). Ingestions reported as a "taste or lick" (n = 53) were included as a dose of 1/10 of the dosage form involved. A clinically important response was defined as bradycardia, hypotension, dysrhythmia, conduction disturbance, or hyperglycemia. The risk of such responses was examined over four dosage intervals (< 2.5 mg, 2.5-5 mg, 5.1-10 mg, and > 10 mg).

RESULTS

The median estimated dose ingested was 5 mg (range 0.25-200 mg). Clinically important responses developed in 27 patients (3.98%), and the prevalence of such response significantly increased from 0% for the lowest to 11.1% for the highest dose interval (p = 0.001). The smallest dose to produce a clinically important response was 2.5 mg (0.15 mg/kg). Children who ingested > 10 mg were 4.4 times more likely to develop clinically important responses than those ingesting < or = 5 mg.

CONCLUSION

Hypotension may occur in children with amlodipine doses as low as 2.5 mg. The National Poison Data System might provide useful insights regarding dose-response.

Effect of delayed activated charcoal on acetaminophen concentration after simulated overdose of oxycodone and acetaminophen

OBJECTIVE

To determine the effect of activated charcoal (AC) on acetaminophen (APAP) absorption kinetics when administered at 1, 2, or 3 h after combined oral overdose with oxycodone.

METHODS

IRB-approved, prospective cross-over study of nine healthy human volunteers ingesting 5 g of APAP + 0.5 mg/kg of oxycodone on each of four study days. On the control day, subjects received no AC. On the remaining study days, subjects ingested 50 g of AC at 1, 2, or 3 h after drug ingestion. We measured serum APAP concentration hourly from 0 through 8 h and compared basic non-compartmental pharmacokinetic parameters.

RESULTS

Compared to the control, AC reduced area under the curve by 43% when given at 1 h (p < 0.0001), 22% when given at 2 h (p = 0.02), and 15% when given at 3 h (p = 0.26). AC at 1 h resulted in a 25% reduction in peak APAP concentration from 48.6 to 36.3 mcg/mL (p = 0.012) with no significant difference when given at 2 or 3 h. There was no significant difference in elimination half-life among the four study days.

CONCLUSION

The effect of AC rapidly declines between 1 and 3 h after combined oral overdose of APAP and oxycodone. AC is unlikely to be beneficial at or beyond 2 h after an overdose of acetaminophen and oxycodone.

Review article: amphetamines and related drugs of abuse

Acute amphetamine toxicity is a relatively common clinical scenario facing the Australasian emergency medicine physician. Rates of use in Australasia are amongst the highest in the world. Clinical effects are a consequence of peripheral and central adrenergic stimulation producing a sympathomimetic toxidrome and a spectrum of central nervous system effects. Assessment aims to detect the myriad of possible complications related to acute amphetamine exposure and to institute interventions to limit associated morbidity and mortality. Meticulous supportive care aided by judicial use of benzodiazepines forms the cornerstone of management. Beta blockers are contraindicated in managing cardiovascular complications. Agitation and hyperthermia must be treated aggressively. Discharge of non-admitted patients from the emergency department should only occur once physiological parameters and mental state have returned to normal. All patients should receive education regarding the dangers of amphetamine use.

Variability in the quality of overdose advice in Summary of Product Characteristics (SPC) documents: gut decontamination recommendations for CNS drugs

AIMS

Deliberate self-poisoning is a major cause of morbidity and mortality. The Summary of Product Characteristics (SPC) document is a legal requirement for all drugs, and Section 4.9 addresses the features of toxicity and clinical advice on management of overdose. The quality and appropriateness of this advice have received comparatively little attention.

METHODS

Section 4.9 of the SPC was examined for all drugs in the central nervous system (CNS) category of the British National Formulary. Advice concerning gut decontamination was examined with respect to specific interventions: induced vomiting, oral activated charcoal, gastric lavage, and other interventions. Data were compared with standard reference sources for clinical management advice in poisoning. These were graded 'A' if no important differences existed, 'B' if differences were noted but not thought clinically important, and 'C' if differences were thought to be clinically significant.

RESULTS

SPC documents were examined for 258 medications from 67 manufacturers. The overall agreement was 'A' in 23 (8.9%), 'B' in 28 (10.9%) and 'C' in 207 (80.2%). Discrepancies were due to inappropriate recommendation of induced emesis in 21.7% (95% confidence interval 17.1, 27.1), gastric lavage in 38.4% (32.7, 44.4), other gut decontamination in 5.8% (3.6, 9.4) and failure to recommend oral activated charcoal in 57.4% (51.1, 63.4).

CONCLUSIONS

Gut decontamination advice in SPC documents with respect to CNS drugs was inadequate. Possible reasons for the observed discrepancies and ways of improving the consistency of advice are proposed.

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).

Dextromethorphan poisoning: An evidence-based consensus guideline for out-of-hospital management

The objective of this guideline is to assist poison center personnel in the appropriate out-of-hospital triage and initial out-of-hospital management of patients with a suspected ingestion of dextromethorphan by 1) describing the process by which an ingestion of dextromethorphan might be managed, 2) identifying the key decision elements in managing cases of dextromethorphan ingestion, 3) providing clear and practical recommendations that reflect the current state of knowledge, and 4) identifying needs for research. This guideline applies to the ingestion of dextromethorphan alone. Co-ingestion of additional substances could require different referral and management recommendations depending on the combined toxicities of the substances. This guideline is based on an assessment of current scientific and clinical information. The expert consensus panel recognizes that specific patient care decisions might be at variance with this guideline and are the prerogative of the patient and the health professionals providing care, considering all of the circumstances involved. This guideline does not substitute for clinical judgment. The grade of recommendation is in parentheses. 1) All patients with suicidal intent, intentional abuse, or in cases in which a malicious intent is suspected (e.g., child abuse or neglect) should be referred to an emergency department (Grade D). 2) Patients who exhibit more than mild effects (e.g., infrequent vomiting or somnolence [lightly sedated and arousable with speaking voice or light touch]) after an acute dextromethorphan ingestion should be referred to an emergency department (Grade C). 3) Patients who have ingested 5-7.5 mg/kg should receive poison center-initiated follow-up approximately every 2 hours for up to 4 hours after ingestion. Refer to an emergency department if more than mild symptoms develop (Grade D). 4) Patients who have ingested more than 7.5 mg/kg should be referred to an emergency department for evaluation (Grade C). 5) If the patient is taking other medications likely to interact with dextromethorphan and cause serotonin syndrome, such as monoamine oxidase inhibitors or selective serotonin reuptake inhibitors, poison center-initiated follow-up every 2 hours for 8 hours is recommended (Grade D). 6) Patients who are asymptomatic and more than 4 hours have elapsed since the time of ingestion can be observed at home (Grade C). 7) Do not induce emesis (Grade D). 8) Do not use activated charcoal at home. Activated charcoal can be administered to asymptomatic patients who have ingested overdoses of dextromethorphan within the preceding hour. Its 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 (Grade D). 9) For patients who have ingested dextromethorphan and are sedated or comatose, naloxone, in the usual doses for treatment of opioid overdose, can be considered for prehospital administration, particularly if the patient has respiratory depression (Grade C). 10) Use intravenous benzodiazepines for seizures and benzodiazepines and external cooling measures for hyperthermia (>104 degrees F, >40 degrees C) for serotonin syndrome. This should be done in consultation with and authorized by EMS medical direction, by a written treatment protocol or policy, or with direct medical oversight (Grade C). 11) Carefully ascertain by history whether other drugs, such as acetaminophen, were involved in the incident and assess the risk for toxicity or for a drug interaction.

Differences in treatment advice for common poisons by poisons centres – An international comparison

OBJECTIVE

To investigate how poisons centres advise on management of common drug poisonings and compare advice on gut decontamination with the EAPCCT/AACT Position Statements.

METHODS

An interactive questionnaire was sent to 14 poisons centres asking about working practices, "top 20" enquiries in 2002, and management of 4 specific drug poisonings.

RESULTS

Replies were received from centres in 11 countries. Annual telephone enquiry numbers varied from 620 (Sri Lanka) to over 50,000 (Germany for 2000). Recommendations for gut decontamination for acetaminophen poisoning were: activated charcoal (AC) alone (5 centres); gastric lavage (GL) alone (1); AC and/or GL (3); AC, GL and/or ipecac (2). Only 40% (4/10) recommended AC and 50% (3/6) GL within 1 hour. Intervention doses for gut decontamination ranged from 100-200 mg/kg (nine centres) and for "high-risk" groups 75-100 mg/kg (3). Plasma concentration for N-acetylcysteine (NAC) treatment ranged from 150 mg/L (four centres) to 200 mg/L (6) at 4 hours. Results were similarly varied for three other common drug poisons (benzodiazepines, amitriptyline, and paroxetine).

CONCLUSIONS

Most poisons centres have protocols that differ in terms of gut decontamination, timing, and intervention doses. Many centres recommend charcoal or gastric lavage after the 1-hour limit proposed in the Position Statements. There is scope for rationalization of approaches to the management of common poisons.

Acute respiratory failure after aspiration of activated charcoal with recurrent deposition and release from an intrapulmonary cavern

OBJECTIVE

To report on the recurrent release of charcoal from an intrapulmonary cavern in a case of acute respiratory failure after charcoal aspiration.

DESIGN

Case report.

SETTING

Anaesthesiological ICU, university hospital.

PATIENT

An 18-year-old ethanol intoxicated comatose patient regurgitated and aspirated activated charcoal during orotracheal intubation.

TREATMENT

After 2 days of mechanical ventilation, the patient was transferred to a tertiary care university hospital. On admission, acute respiratory distress syndrome with bilateral pulmonary infiltrations was diagnosed. The patient's recovery was hampered by recurrent release of charcoal from an intrapulmonary cavern. Sophisticated ventilatory support, prone positioning, secretolytics, repetitive bronchoscopy, and antibiotic therapy may have facilitated bronchoalveolar clearance and weaning after 18 days.

CONCLUSION

Aspiration may be a dramatic complication if charcoal is administered in comatose patients without airway protection. In this case report, advanced intensive care measures were necessary to tackle the special feature of charcoal release from an intrapulmonary cavern.

Toxicology in the critical care unit

Toxicologic conditions are encountered in critically ill patients due to intentional or unintentional misuse of or exposure to therapeutic or illicit drugs. Additionally, toxicities related to medical interventions may develop in hospitalized patients. This review focuses on recent developments in the field of critical care toxicology. Early interventions to decrease absorption or enhance elimination of toxins have limited value. Specific interventions to manage toxicities due to analgesics, sedative-hypnotics, antidepressants, antipsychotics, cardiovascular agents, alcohols, carbon monoxide, and cholinergic agents are reviewed. Hospital-acquired toxicities due to methemoglobinemia, propylene glycol, and propofol should be recognized and treated. The clinician is continually required to incorporate clinical judgment along with available scientific data and clinical evidence to determine the best therapy for toxicologic conditions.

Gastrointestinal decontamination of the poisoned patient

Gastrointestinal decontamination has been a historically accepted modality in the emergency management of oral intoxicants. Theoretically, gastric and whole-bowel emptying procedures hinder absorption, remove toxic substances, prevent clinical deterioration, and hasten recovery. This article presents a current overview of gastrointestinal decontamination. It challenges the accepted precepts of gut decontamination and assesses the utility of syrup of ipecac-induced emesis, orogastric lavage, single-dose-activated charcoal, cathartics, and whole-bowel irrigation.

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.

A retrospective evaluation of analgesic exposures from Izmir, Turkey

The objective of this study is to analyze exposures concerning analgesics that were reported to Dokuz Eylul University Drug and Poison Information Center (DPIC) and admitted to the Department of Emergency Medicine in Dokuz Eylul University Hospital (EMDEU) between 1993 and 2004. Demographics of the patients, characteristics of analgesic exposures, performed treatment attempts and outcome of the poisoned patients were recorded on standard data forms and were then entered into a computerized database program. Statistical analysis was performed by using the chi-square test. The DPIC recorded 55 962 poisoning calls, 48 654 (86.9%) of them related to medicines. Analgesics accounted for 16.3% (7 939 cases) of all medicine-related exposures; among them 446 exposures were admitted to EMDEU. More than half of the analgesic exposure calls and admitted cases involved adults (55.9%, 4 440). Females dominated in all age groups (70.3%, 5 578). Mean age was 20.2 +/- 11.8. The most involved analgesics were paracetamol (47.9%), propionic acid derivatives (16.1%) and salicylates (13.7%). Most of the poisonings were intentional (75.1%), especially in 19-29 years age group of adults and 13-18 years age group of children. Most of the patients reported to DPIC and admitted to EMDEU were asymptomatic (84.4% and 54.7%, respectively). Gastrointestinal decontamination methods were performed more frequently for admitted poisoning cases before hospital admission than reported poisoning cases (61% vs. 23%). Paracetamol ingestion was the most common cause of analgesic exposures reported to our DPIC. Most of the analgesic exposures reported to DPIC were asymptomatic or mild. DPICs have an important role for the referral of analgesic exposures without unnecessary gastrointestinal decontamination procedures.

Activated Charcoal Decreases the Risk of QT Prolongation After Citalopram Overdose

STUDY OBJECTIVE

We determine whether single-dose activated charcoal (SDAC) administration after citalopram overdose reduces the proportion of patients developing abnormal QT prolongation.

METHODS

Data were collected retrospectively for citalopram overdose patients presenting to 8 emergency departments. Demographics, dose, coingested drugs, SDAC administration, and serial ECGs were extracted from medical records. The primary outcome was the proportion of patients who had an observed QT,RR combination at any time above an abnormal threshold, established as a predictor of torsade de pointes. We compared the proportion of patients with QT prolongation who received or did not receive SDAC. These data were analyzed within a Bayesian framework, using probabilities of abnormal QT,RR combinations with and without derived from a previous single-center study. WinBUGS was used to generate posterior estimates and credible intervals of the relative risk by combining the prior probabilities and the study data.

RESULTS

SDAC was administered on average 2.1 hours (range, 0.5 to 6.25 hours) after ingestion in 48 of 254 admissions, and abnormal QT,RR combinations occurred in 2 cases (4.2%), compared with 23 of 206 (11.2%) cases not receiving SDAC. There did not appear to be any clinically important difference in age, sex, dose, and cardiotoxic coingestants between the 2 groups. No cases of torsade de pointes occurred. The estimated relative risk of having an abnormal QT,RR combination for SDAC compared to no SDAC was 0.28 (0.06 to 0.70) (median with 2.5% and 97.5% credible limits). The probability that the relative risk was less than 1.0 was 0.99, which can be interpreted as very strong evidence in favor of a beneficial effect of SDAC. The absolute risk difference was estimated as 7.5% and the median number needed to treat as 13.3.

CONCLUSION

SDAC may be effective in reducing the risk of a prolonged QT in patients after citalopram overdose. Current trends toward nonuse of activated charcoal should be evaluated to determine whether patients poisoned by specific agents may benefit from activated charcoal administration.

Acute child poisonings in Oslo: a 2-year prospective study

AIM

To study the current epidemiology, clinical course and outcome of poisonings among children in Oslo and compare findings to a similar study from 1980.

METHODS

Observational study with prospective inclusion of all children (<15 years of age) with a main diagnosis of acute poisoning treated in hospital or outpatient clinic in Oslo for 2 years.

RESULTS

One hundred seventy-five episodes of acute poisoning were included at the outpatient clinic only (n = 65), the paediatric department only (n = 82) or both (n = 28 referrals). Annual incidence was 97 per 100 000, significantly lower than in 1980 (230 per 100 000). Highest incidence was in 1-year-old males (576 per 100 000). In children <8 years of age, the most common toxic agents were pharmaceuticals (39%) and household products (32%); children > or = 8 years ingested mainly ethanol (46%) or pharmaceuticals (36%). Five percent of all children were comatose, and complications were seen in 13%. All children survived without sequelae. Half of the admissions needed treatment; most commonly used treatments were activated charcoal (33%), gastric lavage (9%) and emetics (9%).

CONCLUSION

The incidence of child poisonings in Oslo has significantly reduced since 1980. Only half of the poisonings needed treatment, most of the poisonings were mild and the clinical outcome was good.

Hyperinsulinemic Euglycemia Therapy for Verapamil Poisoning: A Review

Treatment of patients with verapamil overdose remains challenging. Traditional decontamination and supportive measures with intravenous calcium and vasopressors are the mainstays in initial care. Recently, the successful use of rescue hyperinsulinemic euglycemia therapy has been described in multiple cases. Treatment resulted in improved hemodynamic parameters and increased metabolic efficiency in patients with a low-output, myocardial shock state. Information on clinical use of hyperinsulinemic euglycemia therapy in humans is limited to case reports and small case series; no controlled clinical trials have been done. Hyperinsulinemic euglycemia therapy should be considered for patients with calcium channel blocker overdose who do not respond to initial supportive therapy.

Are One or Two Dangerous? Calcium Channel Blocker Exposure in Toddlers

Unintentional pediatric ingestions of calcium channel blockers are increasing in frequency due to increased use of this antihypertensive class. Potential toxic effects include severe refractory hypotension and death; however, the true toxicity of unintentional pediatric ingestions of 1-2 pills is poorly defined. A literature review was conducted to more closely determine toxic and lethal dosages of calcium channel blockers in the pediatric population under 6 years of age. Results indicate that, although most accidental pediatric ingestions are asymptomatic, a small number do result in cardiovascular instability or even death. The dihydropyridines, particularly nifedipine, and the phenylalkylamine verapamil are most often implicated in symptomatic ingestions. There are no adequate data to identify which children are predisposed to illness, or to determine cutoffs for toxic dosages. However, ingestions of only one pill have been documented to cause severe symptoms, including death. Thus, emergency evaluation to assess potential toxicity is necessary, and gastrointestinal decontamination and in-hospital observation of at least 6 h after toxic ingestion for regular release medications, and 12-24 h after toxic ingestion for sustained release medications is recommended for all cases of unintentional calcium channel blocker ingestion in children younger than 6 years of age.

Backyard mushroom ingestions: no gastrointestinal decontamination--no effect

Treating the unintentional "backyard" mushroom ingestion continues to be controversial. A review of pediatric "backyard" mushroom ingestions was conducted. A Regional Poison Information Center (RPIC) conducted a retrospective review of all mushroom ingestions in children younger than 6 years of age. Data were extracted from the RPIC electronic record system for the years 2000-2003. All exposures that involved "backyard" mushroom ingestions with no gastrointestinal decontamination were included. There were 322 mushroom exposures in children younger than 6 years of age reviewed. The mean age reported was 2.1 years (SD +/- 1.18). All exposures with a definitive outcome had a 24-h follow-up post-exposure to make this determination. There was no effect in 256 cases (79.5%); minor effect in 6 (1.9%); judged as nontoxic, expect no effect in 20 (6.2%); minimal clinical effects possible in 31 (9.6%); and unrelated effect in 9 (2.8%). It was concluded that "backyard" mushrooms do not present a toxicity hazard in unintentional pediatric exposures and require no gastrointestinal decontamination.

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.