Should a benzodiazepine antagonist be used in unconscious patients presenting to the emergency department?

Patients in coma with suspected drug poisoning are commonly encountered in the emergency department. Benzodiazepines are one of the most commonly used drugs in self-poisoning. Flumazenil, a benzodiazepine antagonist has been suggested as a diagnostic and treatment tool in suspected poisoning of unclear cause, but caution is required due to potential side effects. No systemic review of this literature has been done on this topic.

OBJECTIVES

The aim of this study is to examine if flumazenil should be used in patients with coma from suspected drug poisoning.

SEARCH STRATEGY

Randomised controlled trials were identified from the Cochrane Library, Pubmed and EMBASE. Bibliographies from included studies, known reviews and texts were searched. Content experts were contacted.

SELECTION CRITERIA

Randomised controlled trials were eligible for inclusion. Studies were included if patients who presented with altered mental state from suspected drug poisoning were treated with intravenous flumazenil as compared to placebo.

DATA COLLECTION AND ANALYSIS

Data were extracted and methodological quality was assessed independently by two reviewers.

MAIN RESULTS

Seven randomised controlled trials were included. A total of 466 patients were involved. Flumazenil was found to reverse coma from suspected drug poisoning with a relative benefit of 4.45 (95% CI 2.65, 7.45). In terms of major side effects, there was no statistical difference between flumazenil and placebo (RR 2.86, 95% CI 0.12-69.32). However, in terms of minor side effects, flumazenil was associated with a higher incidence of anxiety (RR 2.84, 95% CI 1.28-6.30) and other side effects (RR 3.73, 95% CI 2.078-6.73). There was no difference in the incidence of vomiting (RR 4.28, 95% CI 0.95-19.35).

CONCLUSION

Current evidence shows that flumazenil may be effective in the reversal of coma in patients presenting to the emergency department with coma from suspected drug poisoning.

[A study of 355 consecutive acute poisoning cases admitted to an emergency ward at Copenhagen University Hospital, Bispebjerg in 2001]

INTRODUCTION

Epidemiology describing poisoned patients treated at Copenhagen University Hospital, Bispebjerg has not been published since 1993. We wanted to describe the pattern of intoxications.

MATERIALS AND METHODS

A retrospective study of poisoned patients admitted to the emergency ward during 2001. A computer search of patients discharged with codes T36.0-T65.9 was supplemented by a hand search of the daily admittance lists.

RESULTS

355 patients with confirmed poisonings were found. 97% were poisoned by medications, alcohol (ethanol) or drugs of abuse. Only 3% were poisoned by other agents such as CO. 55% of poisonings were intentional, where paracetamol and benzodiazepines were the preferred agents. Sedative-hypnotics, alcohol, opioids, and drugs of abuse dominated the unintentional overdoses. Patients poisoned by paracetamol were younger and female, with an overrepresentation of young women of foreign origin. Activated charcoal was the preferred method of gastric decontamination. In 52% of the cases various discrepancies between discharge codes and actual poisonings were found. There were 5 deaths, 2 of which were from mixed overdoses with benzodiazepines involving the administration of flumazenil. The 355 cases represented 6% of all patients admitted to the department.

CONCLUSION

Paracetamol, sedative-hypnotics and alcohol were the most common poisoning agents. Mortality was 1%. A general problem of discharge coding was found, which might implicate unreliability in statistics in this field.

Olanzapine overdose: a series of analytically confirmed cases

To describe the spectrum of clinical effects in olanzapine overdose and investigate the factors that predict severe outcomes. We analysed olanzapine-overdose events confirmed by drug analysis. Demographic, clinical and outcome data were recorded for each presentation. The relationship between dose and therapeutic olanzapine use, and outcomes (length of hospital stay, intensive care unit admission, mechanical ventilation, Glasgow coma score <9 and delirium) were investigated. Thirty-seven olanzapine overdose admissions were included. Median age was 30 years (interquartile range: 24-40 years), 24 women and 27 taking olanzapine therapeutically. Median ingested dose was 150 mg (range: 10-1600 mg). Olanzapine overdose was characterized by tachycardia (73%), central nervous system depression (43%), miosis (39%) and delirium (54%), which were either present on admission or developed within 6 h. There was no relationship between the dose and length of hospital stay, intensive care unit admission, Glasgow coma score <9 or delirium, but there was a trend towards more severe outcomes in patients not taking olanzapine therapeutically. Patients with delirium had an increased length of hospital stay and intensive care unit admission rate (50%) and 70% of them required physical or chemical restraint. Olanzapine overdose causes a high rate of delirium and central nervous system sedation that requires significant inpatient resources. Olanzapine overdoses should be initially observed for 6 h and patients not taking olanzapine regularly may have more severe effects.

Coma cocktail: a role for flumazenil?

A common clinical scenario in the emergency department is a patient with a presumed drug overdose. Patients are often unresponsive with respiratory depression and hence unable to give a clear history. When the culprit toxin is known, rapid reversal with administration of the relevant antidote may be life saving. The empirical administration of a ‘coma cocktail’ consisting of naloxone, glucose and thiamine is common in many emergency departments. It is tempting to add flumazenil to this cocktail if there is a suspicion of benzodiazepine misuse; however, the possibility of mixed overdose or any suggestion of long-term benzodiazepine use should influence management choices.

Serum Levels of Olanzapine in a Non-Fatal Overdose

Olanzapine is a widely used second generation antipsychotic drug. Case reports of intoxications have been published, but reports in the literature of non-fatal intoxications of olanzapine containing repeated measurements of serum levels are scarce. Therefore, this case of non-fatal olanzapine intoxication is presented, in which 19 blood samples were drawn during 2 weeks. The highest (initial) measured value was estimated at 800 pg/L. This patient ingested 550 mg of olanzapine resulting in clinical signs of intoxication, including seizures. Because the patient was found the day after the intoxication, the initial concentration had probably been higher. The pharmacokinetics of olanzapine has been described as linear and dose-proportional throughout the therapeutic dosing range. Large overdoses, however, have been described to show non-linear pharmacokinetics. In this study's series of serum concentrations, a two-phase elimination was seen, with an initial elimination half-life of about 24 h during the first 3 days, followed by a second phase with a half-life of about 2.5 days. The patient in this case recovered completely. Because the elimination time after intoxication can be considerably longer than expected, it is recommended that the patient's serum concentrations after intoxication be monitored.

[Carbohydrate metabolism in acute poisoning with xenobiotics]

The aim of the study was to evaluate carbohydrate metabolism in patients hospitalised because of acute intoxication with xenobiotics.

MATERIAL AND METHODS

An analysis of 3628 patients (1553 females and 2075 males; age: 40.6 +/- 15.9 y) hospitalized at the Ward of Toxicology and Environmental Diseases because of acute poisoning in 2004-2006 was done. The patients with diabetes mellitus diagnosed prior to hospitalisation were excluded from the analysis. The blood ethanol concentration was measured, medication drugs and/or psychoactive substance screening test were performed in all patients on admission. Fasting glucose level on admission and control level on second or third day of hospitalisation were determined. Risk ratio of hyperglycaemia according to toxic agent was assessed using multiple regression model considering age, gender, and the patient education.

RESULTS

In 18.2% (398 males and 254 females) of the patients the blood glucose level on admission was > or = 7.8 mmol/l; in u 3.6% (78 males and 50 females) > or = 11.1 mmol/l. In 24 (0.6%) of the patients glycaemia on admission was < or = 3.5 mmol/l. Control fasting glucose level of > or = 7.0 mmol/l was determined in 115 males and 76 female patients. 42% elevation in risk of hyperglycaemia was noted in acute carbon monoxide poisoning (OR = 1.42; 95% PU: 1.11-1.82). In ethanol intoxicated patients 12% drop in risk of hyperglycaemia was noted (OR = 0.88; 95% PU: 0.72-1.07). Benzodiazepine poisoning diminished risk of hyperglycaemia in 36% (OR=0.64; 95%PU: 0.48-0.84). Risk of hyperglycaemia in poisoning by medicines co-ingested with ethanol was always lower compared to poisoning with the single agent.

CONCLUSION

A higher risk of hyperglycaemia was related to acute carbon monoxide poisoning whereas lower risk of hyperglycaemia was attributed to benzodiazepines and alcohol. A frequency of hypoglycaemia in the group of poisoned patients was much more lower compared to hyperglycaemia.

Toxicologic findings in suicide: a 10-year retrospective review of Kentucky medical examiner cases

Toxicologic analysis is an integral component in the investigation of suicide and requires correlation with a detailed scene inspection, with an extensive exploration into the decedent's medical and social background to uncover suicidal ideation or intent and a postmortem examination of the body. In this review, the authors analyzed 2864 cases classified as suicide upon autopsy and toxicologic examinations between 1993 and 2002 in the Kentucky Division of Medical Examiner's Services. Blood and urine were collected in 95.0% and 72.3% of cases, respectively. A total of 32.5% of the victims had negative blood toxicologic results, and 52.7% of urine toxicology screens yielded no drugs. Analysis of the data indicated that 3 times as many women had taken antidepressants and more than twice as many had consumed opioids. Drug toxicity ("overdose") ranked as the third (9.9%) leading cause of suicide after firearm injury (67.5%) and hanging (13.7%). Women succumbed to drug toxicity more than men (27.5% versus 5.9%). Of the overdose deaths, 66.5% had a negative blood alcohol concentration (BAC), while antidepressants, opioids, and benzodiazepines were detected in blood in 54.4%, 37.4%, and 29.2% of the subjects, respectively. The collection of these data serves the goals of public health and clinicians in devising strategies for suicide prevention.

A Clinical Tool for Assessing Risk After Self-Harm

STUDY OBJECTIVE

Our aim is to develop a risk-stratification model for use by emergency department (ED) clinical staff in the assessment of patients attending with self-harm.

METHODS

Participants were patients who attended 5 EDs in Manchester and Salford, England, after self-harm between September 1, 1997, and February 28, 2001. Social, demographic, and clinical information was collected for each patient at each attendance. With data from the Manchester and Salford Self-Harm Project, a clinical decision rule was derived by using recursive partitioning to discriminate between patients at higher and lower risk of repetition or subsequent suicide occurring within 6 months. Data from 3 EDs were used for the derivation set. The model was validated with data from the remaining 2 EDs.

RESULTS

Data for 9,086 patients who presented with self-harm were collected during this study period, including 17% that reattended within 6 months and 22 patients who died by suicide within 6 months. A 4-question rule, with a sensitivity of 94% (92.1-95.0% [95% confidence interval]) and specificity of 25% (24.2-26.5% [95% confidence interval]), was derived to identify patients at higher risk of repetition or suicide.

CONCLUSION

Application of this simple, highly sensitive rule may facilitate assessment in the ED and help to focus psychiatric resources on patients at higher risk.

Fatal poisoning in Nordic drug addicts in 2002

The present study from 2002 includes medicolegally examined fatal poisonings among drug addicts in the five Nordic countries: Denmark, Finland, Iceland, Norway and Sweden. A common definition "drug addict" is applied by the participating countries. The number of deaths, age, sex, place of death, main intoxicant and other drugs present in the blood are recorded in order to obtain national data, as well as comparable Nordic data and data comparable to earlier studies from 1997 and 1991. The Icelandic results are commented on separately due to the low number of cases. The most fatal overdoses are seen in Norway, in both the death rate (number per 100,000 inhabitants=8.44) and in absolute number (n=232). The comparable figures for the other four countries are Denmark 5.43 (n=175), Iceland 3.6 (n=6), Finland 2.93 (n=94) and Sweden 2.56 (n=136). In earlier studies from 1991 and 1997, the highest death rate is seen in Denmark, with Norway as number two. Denmark is the only country where the death rate decreases from 1997 to 2002. A relatively large increase in deaths in the younger age groups (<30 years) is noted from 1997 to 2002, except in Denmark, where only a small increase in overdose deaths in very young people (15-19 years) is observed. Females account for 12-20% of the overdoses (three out of six deaths in Iceland). Relatively fewer deaths are recorded in the capital areas in 2002 than in 1997 and 1991, suggesting more geographically widespread drug use in the Nordic countries. Heroin/morphine is the single most frequently encountered main intoxicant, varying from 10% of the cases in Finland to 72% of the cases in Norway. Finland differs from the other countries in that a high percentage of the fatal overdoses in Finland are not caused by an illicit drug; buprenorphine overdoses are seen, and relatively few deaths resulting from heroin are seen. Methadone is the main intoxicant in 41% of the Danish overdose cases, 15% of the Norwegian cases, 4% of the Swedish cases and none of the Finnish overdose cases, an observation probably linked to different national prescription rules for methadone. The analytical screening reveals extended polydrug use. Frequently seen substances, in addition to the main intoxicant are amphetamine, tetrahydrocannabinol (THC), benzodiazepines and ethanol.

Nonfatal Suicidal Olanzapine Overdose

There is an increase in the usage of olanzapine because of its relatively benign adverse effect profile. We report a case of suicidal overdose who survived after ingestion of 1600 mg of olanzapine requiring minimal intervention. Fluctuation in mental status suggestive of toxic delirium was noted during recovery from overdose. There was minimal alteration in the clinical and biochemical parameters. Olanzapine is safe in monointoxication as evident from this case study.

Testing positive for methadone and either a tricyclic antidepressant or a benzodiazepine is associated with an accidental overdose death: analysis of medical examiner data

OBJECTIVES

Patients in emergency departments who use methadone frequently use tricyclic antidepressants (TCAs) and/or benzodiazepines (BZDs). This is a potentially dangerous drug combination. The authors hypothesized that the presence of methadone and a TCA, a BZD, or both is associated with an "accidental" overdose (AOD) death more often than a death from any other cause.

METHODS

A retrospective chart review of New York City Office of Chief Medical Examiner data for 2003 was performed. Decedents who tested positive for methadone that were classified as an AOD death, as determined by the medical examiner, were compared with deaths from all other causes for the presence of a TCA, a BZD, or both. A logistical regression was performed to develop a multivariate model identifying additional variables associated with a methadone-positive AOD death. A p-value of <0.05 was considered significant, and 95% confidence intervals (CIs) were calculated.

RESULTS

In 2003, there were 5,817 medical examiner cases, of which 500 (8.6%) were methadone positive. Of the methadone-positive cases, 493 were available for analysis; 95 (19.3%) were TCA positive and 158 (32.0%) were BZD positive. The odds of having an AOD death in methadone-positive decedents testing TCA positive, BZD positive, or both were 2.11 (95% CI = 1.32 to 3.37; p < 0.01) for TCAs, 1.66 (95% CI = 1.12 to 2.45; p < 0.02) for BZDs, and 4.34 (95% CI = 1.97 to 9.56; p < 0.001) for both. The multivariate logistic regression of analytes revealed the following covariates associated with an AOD death as well: amitriptyline, cocaine, morphine, or opiates.

CONCLUSIONS

Among the methadone-positive cases, testing positive for a TCA, a BZD, or both was associated with an AOD death.

Pontine haemorrhage mimicked by an olanzapine overdose

Olanzapine, an atypical antipsychotic of the thienobenzodiazepine class, has been on the market since 1996. Its popularity has increased over recent years because of excellent clinical results as well as a favourable side effect profile. Mirroring this increased olanzapine use has been a rise in the number of non-accidental overdoses. The clinical picture of olanzapine overdose can be surprisingly variable. In the case presented, the patient's low Glasgow Coma Score prevented an accurate history being taken. Examination revealed bilateral upgoing plantars, pinpoint pupils, increased tone, and brisk reflexes; however initial investigations, including an urgent CT head, were normal. The patient required 24 hours of intensive care before he regained consciousness and admitted to the overdose. Although there are several reports of olanzapine mimicking opiate intoxication in overdose, this is one of the first cases where overdose has mimicked an intracerebral event. The authors highlight some of the literature regarding clinical presentation and treatment options, and discuss the relation between olanzapine therapy and diabetes.

Deaths From Drug Overdose and Toxicity in Turkey

Turkey is located on the main overland connection between Asia and Europe, making the country potentially vulnerable to drug trafficking and its associated harms. The aim of the present study is to explore the frequency of all deaths from drug overdose and toxicity in Turkey and to describe some of the characteristics of these deaths. We collected data on all deaths from drugs in Turkey between 1997 and 2001 using records from the Council of Forensic Medicine. Data obtained from autopsy reports were retrospectively analyzed. In the present study, 374 deaths from drugs were reported in Turkey, with a mortality rate of 0.17 per 100,000 population. Highest mortality rates were found in Istanbul (0.83) and Gaziantep (0.71). The mean age was 34.0, and most cases (71.7%) were below the age of 40. The proportion of female cases was 13.6%. Opiates were implicated in 91.5% of deaths and benzodiazepines in 25.9%. Two fifths (38.8%) of the cases involved use of more than 1 drug. In 36.6% of cases, the route of final drug administration was by injection. The most common location of death was at a home (33.7%). Interventions to reduce drug use nationally are urgently required. International cooperation in social-educational activities, scientific research, and security measures is essential for this war.

Antipsychotic poisoning in young children: a systematic review

The aim of this review was to determine the spectrum and severity of effects of unintentional antipsychotic poisoning in children. A computerised literature search of MEDLINE (1966 to February 2005) and EMBASE (1980 to February 2005) was undertaken. The Internet was searched using URL: www.google.com. The proceedings of the North American Congress of Clinical Toxicology (NACCT) and the European Association of Poisons Centres and Clinical Toxicologists (EAPCCT) were hand searched. All cases of unintentional antipsychotic (all classes) poisoning in children aged 0-6 years were included. The data extracted included the age, weight, antipsychotic, dose, clinical effects, treatment and outcomes. The toxic dose was estimated as the lowest dose causing objective adverse effects.Sixty-eight reports were identified. Few contained all of the required information. Most of the case series included multiple antipsychotics with limited information on individual drugs or all ages with limited paediatric information. For most antipsychotics the ingestion of one tablet caused symptoms that were sometimes severe and usually lasted from 1 to 3 days. Extrapyramidal symptoms (EPS) were often delayed for up to 12-24 hours. Chlorpromazine caused CNS depression, hypotension and miosis; EPS and cardiac effects were rare, and the toxic dose was estimated to be 15 mg/kg. Haloperidol caused drowsiness (rarely coma) and over one-half of patients had neuromuscular effects (mainly EPS), with a toxic dose estimated at 0.15 mg/kg. Thioridazine caused CNS depression and potentially cardiac effects, with a toxic dose of 1.4 mg/kg. Atypical antipsychotics caused significant CNS depression (except risperidone); EPS were less common. Toxic doses were clozapine 2.5 mg/kg, olanzapine 0.5 mg/kg and aripiprazole 3 mg/kg. EPS responded to anticholinergic drug treatment. In summary, unintentional antipsychotic ingestion in children can cause severe effects that last 1-3 days, often with one tablet. Children potentially ingesting a toxic dose or who are symptomatic should be considered for assessment in hospital. Most cases resolve with good supportive care. Toxic doses are only estimates that are based on limited data and should be used with caution until prospective studies are undertaken.

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.

Pharmacokinetics of the active metabolites of ethyl loflazepate in elderly patients who died of asphyxia associated with benzodiazepine-related toxicity

We determined the pharmacokinetics of ethyl loflazepate (Lof) in elderly patients who died of benzodiazepine-related toxicity. Three elderly patients with body mass indexes of less than 17 kg/m2 died of asphyxia after having taken maintenance doses of Lof for 2 to 3 weeks. We measured serum concentrations of the active metabolites of Lof using gas chromatography-mass spectrometry and a benzodiazepine receptor assay to determine the pharmacokinetics of each. On admission, the serum concentrations of the active metabolites of Lof ([Lofl) were 256 ng/mL, 425 ng/mL, and 177 ng/mL in cases 1, 2, and 3, respectively. Serum benzodiazepine-receptor binding activities, expressed as diazepam equivalent concentrations ([Bz]), were 1800 ng/mL, 2200 ng/mL, and 1500 ng/mL. The T1/2(beta) of [Lof] were 124 and 121 h in cases 1 and 2 and the T1/2(beta) of [Bz] were 75 and 87 h. The distribution volume in the elderly was reduced due to a small lipid compartment, and total drug clearance was decreased due to the decline in liver and kidney function. These changes did not prolong T1/2(beta) but did increase plasma concentrations of active metabolites, especially in case 2, and a slight decrease in protein binding increased the amount of free active metabolites greatly.

Acute poisoning: understanding 90% of cases in a nutshell

The acutely poisoned patient remains a common problem facing doctors working in acute medicine in the United Kingdom and worldwide. This review examines the initial management of the acutely poisoned patient. Aspects of general management are reviewed including immediate interventions, investigations, gastrointestinal decontamination techniques, use of antidotes, methods to increase poison elimination, and psychological assessment. More common and serious poisonings caused by paracetamol, salicylates, opioids, tricyclic antidepressants, selective serotonin reuptake inhibitors, benzodiazepines, non-steroidal anti-inflammatory drugs, and cocaine are discussed in detail. Specific aspects of common paediatric poisonings are reviewed.