Fatal poisonings attributed to benzodiazepines in Britain during the 1980s

Relative toxicity of benzodiazepines and hypnotics commonly used for self-poisoning: An epidemiological study of fatal toxicity and case fatality

The relative toxicity of anxiolytic and hypnotic drugs commonly used for self-poisoning was assessed using data on suicides, prescriptions and non-fatal self-poisonings in England, 2005-2012. Data on suicide by self-poisoning were obtained from the Office for National Statistics, information on intentional non-fatal self-poisoning was derived from the Multicentre Study of Self-harm in England and data on prescriptions in general practice from the Clinical Practice Research Datalink. We used two indices of relative toxicity: fatal toxicity (the number of fatal self-poisonings relative to the number of individuals prescribed each drug) and case fatality (the number of fatal relative to non-fatal self-poisonings). Diazepam was the reference drug in all analyses. Temazepam was 10 times (95% confidence interval 5.48-18.99) and zopiclone/zolpidem nine times (95% confidence interval 5.01-16.65) more toxic in overdose than diazepam (fatal-toxicity index). Temazepam and zopiclone/zolpidem were 13 (95% confidence interval 6.97-24.41) and 12 (95% confidence interval 6.62-22.17) times more toxic than diazepam, respectively (case-fatality index). Differences in alcohol involvement between the drugs were unlikely to account for the findings. Overdoses of temazepam and zopiclone/zolpidem are considerably more likely to result in death than overdoses of diazepam. Practitioners need to exercise caution when prescribing these drugs, especially for individuals who may be at risk of self-harm, and also consider non-pharmacological options.

The Large Role of Prescription Drugs in Accidental Drug Deaths

Drug abuse may involve illicit drugs, prescription drugs, or the combination of illicit and prescription drugs, with or without the use of alcohol. Historically, illicit drugs have been responsible for many of the drug-related deaths investigated by medical examiner and coroner offices. However, in more recent years, deaths resulting from prescription drugs have become increasingly more common. This study reviewed all accidental (unintentional) drug deaths that were investigated at a medical examiner's office over a one-year time frame. The study revealed that prescription drugs made up the largest category of drug deaths, followed by prescription drug/illicit drug combinations, followed by illicit drugs. Drugs capable of causing or contributing to significant respiratory insufficiency such as opioids, benzodiazepines, relaxants (defined as muscle relaxants or sleep medications), and alcohol, or some combination thereof, were detected in 197 out of 256 (77%) of all accidental drug deaths, and were detected in 132 out of 138 (95%) of all prescription drug deaths (cases without any illicit drugs detected). These prescription drugs were most often found in combination, and their similar respiratory depressant effects can be cumulative and deadly.

Concentrations of alprazolam in blood from impaired drivers and forensic autopsies were not much different but showed a high prevalence of co-ingested illicit drugs

Alprazolam is a benzodiazepine anxiolytic widely prescribed for treatment of panic-disorder and social phobias, although this medication is also subject to abuse. In this paper, the concentrations of alprazolam in venous blood samples from impaired drivers were compared with femoral blood samples from forensic autopsies classified as intoxication or other causes of death (e.g. natural, trauma). After liquid-liquid extraction (n-butyl acetate) alprazolam was determined in blood by capillary gas chromatography with a nitrogen-phosphorous detector. The mean (median) and range of alprazolam concentrations in blood from impaired drivers (n = 773) were 0.08 mg/L (0.05 mg/L) and 0.02-3.9 mg/L, respectively. Many traffic offenders had co-ingested ethanol (13%), amphetamine (46%), cannabis (32%), or heroin (14%), as well as other drugs. In deaths attributed to drug intoxication, the mean (median) and range of alprazolam concentrations in blood (n = 438) were 0.10 mg/L (0.06 mg/L) and 0.02-1.6 mg/L, respectively, which were not much different from other causes of death (n = 278); 0.08 mg/L (0.05 mg/L) and 0.02-0.9 mg/L. Median concentrations of alprazolam in blood from living and deceased persons did not seem to depend on the number of co-ingested substances. The result of this pharmacoepidemiological study suggests that alprazolam is a fairly innocent drug when used as monotherapy, but toxicity problems arise when co-ingested with illicit drugs and/or psychoactive medication.

Alcohol and drugs in epilepsy: pathophysiology, presentation, possibilities, and prevention

The potentially serious outcomes from ingestion of and dependence on toxins make this an important topic for epileptologists. We must be aware of the potential for harm from compounds that may be freely available, yet patients may try to conceal their use. Problematic compounds may cause seizures either acutely or on withdrawal: Their use may reduce effectiveness of antiepileptic drugs, or may simply promote and enhance chaotic lifestyles. Any or all of these factors may worsen seizure control or even directly cause seizures. This article highlights the pathophysiology behind provoked seizures, provides clues to diagnosis, and then outlines the steps that clinicians should take to reduce the deleterious effects of toxic compounds.

The discovery of chlordiazepoxide and the clinical introduction of benzodiazepines: half a century of anxiolytic drugs

The clinical introduction of chlordiazepoxide half a century ago was one of the major breakthroughs in the history of psychopharmacology, as it opened the door for the benzodiazepine saga, the pharmacological family par excellence in the treatment of anxiety disorders. This review analyses the discovery of this drug, which was filled with chance events, and numerous chemical and clinical errors of approach. Chlordiazepoxide, initially called methaminodiazepoxide, was patented in 1958 and introduced in clinical treatment in 1960 under the brand name Librium®. The benzodiazepines became the most widely prescribed drugs worldwide, provided truly effective treatment for "minor forms" (neuroses) of mental disorders for the first time, increased the quality of scientific methodology in clinical research, and enabled the development of new etiopathogenic theories for anxiety disorders, especially after the discovery in 1977 of their high-affinity receptor complex.

Self-poisoning by the older person: a review

Suicide is a major health issue worldwide and is among the top ten causes of death in many countries. Much research, media attention and public health initiatives are focused on reducing the suicide rate among adolescents and young adults. In many countries, however, it is the elderly population with the greatest number of suicides, the majority of which die by drug overdose. This is commonly explained by an increased suicidal intent among older people due to co-morbidity and social isolation. The physical vulnerability of elderly people to potential toxins however is also likely to play an important role. This review examines the epidemiology of elderly suicide, considers commonly implicated drugs, and discusses associated risk factors in this complex and multifactorial problem.

Suicide by Multidrug Ingestion

A fatal suicidal ingestion of drugs, together with activated charcoal, is reported. The death occurred 31 hours after the self-administration. The autopsy revealed a large amount of gastric content that appeared to be a compact mass of black color. Toxicologic analyses showed the presence of toxic levels of desalkylflurazepam and trazodone; metamizole and pridinol were also detected. The obtained results supported the hypothesis of a death due to acute intoxication delayed by the self-administration of activated charcoal, which elimination was probably hindered by the action of pridinol.

Does high-dose buprenorphine cause respiratory depression?: possible mechanisms and therapeutic consequences

Buprenorphine is an opioid agonist-antagonist with a 'ceiling effect' for respiratory depression. Compared with methadone, its unique pharmacology offers practical advantages and enhanced safety when prescribed as recommended and supervised by a physician. Buprenorphine has been approved in several countries as an efficient and safe maintenance therapy for heroin addiction. Its use resulted in a salutary effect with a reduction in heroin overdose-related deaths in countries that implemented office-based buprenorphine maintenance. In France, however, where high-dose buprenorphine has been marketed since 1996, several cases of asphyxic deaths were reported among addicts treated with buprenorphine. Death resulted from buprenorphine intravenous misuse or concomitant sedative drug ingestion, such as benzodiazepines. In these situations of abuse, misuse, or in association with elevated doses of psychotropic drugs, buprenorphine may cause severe respiratory depression. Unlike other opiates, the respiratory effects from buprenorphine are not responsive to naloxone. However, the exact mechanism of buprenorphine-induced effects on ventilation is still unknown. The role of norbuprenorphine, the main N-dealkylated buprenorphine metabolite with potent respiratory depressor activity, also remains unclear. Experimental studies investigating the respiratory effects of combinations of high doses of buprenorphine and benzodiazepines suggested that this drug-drug interaction may result from a pharmacodynamic interaction. A pharmacokinetic interaction between buprenorphine and flunitrazepam is also considered. As there are many questions regarding the possible dangers of death or respiratory depression associated with buprenorphine use, we aimed to present a comprehensive critical review of the published clinical and experimental studies on buprenorphine respiratory effects.

Gas-phase fragmentation of protonated benzodiazepines

Protonated 1,4-benzodiazepines dissociate in the gas phase by the common pathway of CO elimination and by unique pathways dictated by the substituents; the latter typically differentiate one benzodiazepine from another. Protonated 3-dihydro-5-phenyl-1,4-benzodiazepin-2-one, the base diazepam devoid of substituents, dissociates by eliminating CO, HNCO, benzene, and benzonitrile. Mechanisms of these reactions are proposed with ionic products being resonance stabilized. The abundant [MH-CO]+ ion dissociates to secondary products via elimination of benzene, benzonitrile, the NH2 radical, and ammonia, yielding again ionic products that are stabilized by resonance.

Acute flurazepam intoxication: a case report

A fatality due to ingestion of flurazepam is reported. Flurazepam is a benzodiazepine, a widely prescribed hypnotic drug for use in sleep disorders. There are only few documented reports of the disposition of flurazepam in deaths due to overdose. A 68-year-old woman was found deceased at home with no evidence of trauma or asphyxia. Toxicologic analyses were performed and drug levels measured by means of gas chromatography coupled to mass spectrometry. The flurazepam concentration in each specimen was as follows: heart blood 2.8 microg/mL, bile 323 microg/mL, and urine 172 microg/mL. Presence of flurazepam into gastric content was observed too. Based on the autopsy findings, patient history, and toxicologic results, the cause of death was determined to be acute intoxication of flurazepam and the manner, suicide.

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.

Flumazenil—Treatment or Toxin

Flumazenil is frequently administered to the poisoned patient. Seizures may be precipitated and resedation may occur in patients who awakened following flumazenil administration. Seizures may increase morbidity and mortality of the overdose. Benefit:Risk ratio of administering flumazenil should be determined in each overdose patient. Indications for flumazenil are limited.

Alprazolam is relatively more toxic than other benzodiazepines in overdose

AIMS

To describe alprazolam poisoning and the relative toxicity of alprazolam compared with other benzodiazepines.

METHODS

A database of consecutive poisoning admissions to a regional toxicology service was searched to identify consecutive benzodiazepine deliberate self poisonings, which were coded as alprazolam, diazepam or other benzodiazepine. Major outcomes used were length of stay (LOS), intensive care (ICU) admission, coma (GCS < 9), flumazenil administration and requirement for mechanical ventilation. Prescription data were obtained for benzodiazepines for the study period.

RESULTS

There were 2063 single benzodiazepine overdose admissions: 131 alprazolam overdoses, 823 diazepam overdoses and 1109 other benzodiazepine overdoses. The median LOS for alprazolam overdoses was 19 h which was 1.27 (95% CI 1.04, 1.54) times longer compared with other benzodiazepines by multiple linear regression. For patients with alprazolam overdoses, 22% were admitted to ICU which was 2.06 (95% CI 1.27, 3.33) times more likely compared with other benzodiazepines after multivariate analysis adjusting for age, dose, gender, time to ingestion and co-ingested drugs. Flumazenil was administered to 14% of alprazolam patients and 16% were ventilated, which was significantly more than for other benzodiazepine overdoses (8% and 11%, respectively). Twelve percent of alprazolam overdoses had a GCS < 9 compared with 10% for other benzodiazepines. From benzodiazepine prescription data, total alprazolam prescriptions in Australia increased from 0.13 million in 1992 to 0.41 million in 2001. Eighty five percent of prescriptions were for panic disorder, anxiety, depression or mixed anxiety/depression.

CONCLUSIONS

Alprazolam was significantly more toxic than other benzodiazepines. The increased prescription of alprazolam to groups with an increased risk of deliberate self poisoning is concerning and needs review.

Évaluation de la prescription et de l’utilisation des benzodiazépines dans la commune de Saint-Louis du Sénégal : enquête auprès des patients

Prescription and use of benzodiazepins were evaluated with a patients survey. Direct interview were conducted with 150 patients in ten pharmacies in the city of Saint-Louis, Senegal from January to June 2002. Ten of the 15 retail pharmacies in this city agreed to participate in the survey. All patients gave their agreement to participate to the study; the questionnaire contained essentially closed questions. Writers of prescriptions were general practitioners (38.67%), specialists (34.67%), nurses (18%) and midwifes (8.66%). The most prescribed benzodiazepins were prazepam, dipotassic clorazepate, lorazepam and diazepam. Use of these drugs during night is most recommended. Nevertheless, 26.67% of the prescriptions indicated the drug should be use during the day. The period of use was between one and three Months for 33.99% of patients and three Months or more in 42%. Benzodiazepins were used by 66.67% for insomnia, alone or associated with another condition, for anxiety by 14.6% and for epilepsy by 10%. Prescriptions were for benzodiazepins alone in 47.37% of the patients and in combination with other psychotropic drugs for 19.33%. Somnolence and dependence were the most reported side effects.

Comparison of the fatal toxicity index of zopiclone with benzodiazepines

BACKGROUND

Zopiclone is a hypnosedative structurally unrelated to the benzodiazepines but operating at the same receptor complex. Although zopiclone has been used in clinical practice for many years, relatively little is known of its relative toxicity in comparison with other hypnosedatives.

METHOD

Deaths, where hypnosedatives were implicated, in New Zealand (NZ) in 2001 were identified from a chemical injury database. Prescription and aggregate defined daily dose (DDD) data forNZ in 2001 were obtained from a national prescribing database. Rates of death per prescription and DDD, and relative rates between individual hypnosedatives and benzodiazepines, and their respective 95% CI were calculated.

RESULTS

Of the 200 poisoning deaths in NZ for 2001, 39 involved hypnosedatives, and zopiclone was involved in 12. Hypnosedatives were the sole agents in only one death and were the primary agents in eight deaths. Zopiclone was the sixth most commonly involved agent in poisoning deaths in NZ in 2001. The relative rate of death per prescription (95% CI) and DDD (95% CI) of zopiclone compared with benzodiazepines were 1.04 (0.49-2.05) and 0.59 (0.28-1.16), respectively. The relative rates of death per DDD (95% CI) for alprazolam and chlormethiazole compared with the other sedatives/anxiolytics were 6.2 (1.6-17.0) and 20.9 (2.5-79.8) respectively.

CONCLUSIONS

The fatal toxicity for zopiclone was not significantly different from that for benzodiazepines as a group when adjusted for usage, whereas alprazolam and chlormethiazole had greater toxicity. Hypnosedatives are contributory factors rather than primary substances in poisoning deaths.

Changes in Fatalities Due to Overdose of Anxiolytic and Sedative Drugs in the UK (1983???1999)

OBJECTIVE

To establish the frequency with which anxiolytic and sedative drugs result in fatal poisonings and to examine longitudinal changes in poisoning deaths.

METHOD

The number of fatal poisonings between 1983 and 1999 in England, Scotland and Wales due to a single anxiolytic or sedative drug was obtained from the Department of Health in the UK. This was divided by the number of prescriptions for these drugs in England and Scotland to derive a fatal toxicity index (FTI) of deaths per million prescriptions.

RESULTS

Chloral hydrate, clomethiazole, barbiturates, and related sedatives had much higher FTIs than benzodiazepines, buspirone, zolpidem and zopiclone. There has been a substantial reduction in the annual number of deaths from sedative drug poisoning between 1983 and 1999. This has been due to a sustained reduction in prescriptions for high toxicity drugs and more recently a major reduction in temazepam deaths that coincided with the withdrawal of gelatin capsule formulations.

CONCLUSION

Deaths would be expected to be further reduced if there were reduced prescriptions of high toxicity drugs--and the continuing need for short-acting barbiturates, clomethiazole and chloral hydrate should be questioned.

The role of benzodiazepines in elderly suicides

AIMS

In Sweden, suicides by drug poisoning have decreased in the population at large during the past two decades. However, drug poisoning suicides increased among the elderly during this period. Suicides by benzodiazepine poisoning increased in this age group despite a reduction in prescription sales of these drugs. This study aims therefore to determine the role of benzodiazepines in suicide late in life.

METHODS

Information concerning all definite suicides and deaths due to "undetermined" causes recorded among Swedish citizens aged 65 and above during 1992 - 96 was obtained from the Cause-of-Death Register. Death certificates were scrutinized to determine the type of drug employed in drug-related suicides. Results of the post mortem screening for drugs and alcohol were then examined.

RESULTS

A benzodiazepine was implicated in 216/548 (39%) of the drug poisoning suicides recorded among the elderly. Death certificates revealed that a benzodiazepine was the sole agent in 72% of these cases. Flunitrazepam or nitrazepam were implicated in 90% of the single benzodiazepine suicides. In addition to the suicides classified as drug poisonings, 82 cases were found in which a drug may have contributed to the cause of death. Benzodiazepines predominated. The terminal cause of death was drowning, often in the victim's own bathtub, in three-quarters of these cases. The annual fatality ratios for the newer benzodiazepine-like hypnotics zopiclone and zolpidem appear to be on the rise.

CONCLUSION

Benzodiazepines, especially the hypnotics flunitrazepam and nitrazepam, are common in drug poisoning suicides in the elderly and should be prescribed with caution for this age group.

Fatal methadone toxicity: signs and circumstances, and the role of benzodiazepines

OBJECTIVE

To describe the signs and symptoms and circumstances of fatal methadone toxicity and investigate the role of benzodiazepines in these deaths.

METHODS

Data were extracted from 1994 New South Wales (NSW) coronial files and cause of death established independently. Cases were grouped according to the likely source of methadone. Data describing the clinical history and circumstances of death were extracted from witnesses' and police statements.

RESULTS

Methadone contributed to the deaths of 57 of the 87 adult coronial cases in which it was detected in NSW in 1994. The most commonly reported early signs of severe methadone toxicity were ataxia, slurred speech and evident euphoria. The late signs were unconsciousness, loud snoring and brown pulmonary oedema fluid coming from the mouth or nose. Death occurred an average 5.1 and 6.0 hours after oral ingestion and intravenous injection of methadone, respectively. Benzodiazepines were significantly more likely to have contributed to deaths from methadone toxicity among maintenance patients and people taking methadone tablets for pain relief than deaths involving diverted methadone syrup and deaths to which methadone did not contribute (OR 4.8, 95% 1.7 to 14.4).

CONCLUSIONS AND IMPLICATIONS

Benzodiazepines may contribute to deaths from methadone toxicity by increasing upper airways obstruction. Victims would have had a greater chance of survival if they had either been placed in the coma position or given mouth-to-mouth ventilation and an ambulance had been called. Benzodiazepines are more likely to contribute to fatal methadone toxicity in newly admitted maintenance patients and those taking methadone tablets for pain relief.

Parasuicidal poisoning treated in a Greek medical ward: epidemiology and clinical experience

OBJECTIVE

To study the epidemiology of acute poisoning patients presenting to an acute medical service ward in a Greek hospital between January 1998 and December 2000.

DESIGN

Prospective case series.

RESULTS

A total of 273 patients with self-poisoning were included in the study. This represented 3.8% of the overall admissions to the unit. The mean age of patients was 33, the most frequent age group being that aged 20-30 years (36.2% of total) with a male-to-female ratio of 1:1.97. Sixty per cent of patients was admitted within 4 h. Those from urban areas comprised 76.2% and 23.8% from rural areas. The most frequently ingested agents were psychopharmaceuticals (37.4%) and analgesics/anti-rheumatics (32.6%). Pesticides (7.7% of total) were most frequently used by patients coming from rural areas (32.3% of patients from rural areas). Alcohol was included in the overdose in 8.4%. Of the patients, 16.2% had a previous history of overdose. In this case series, psychiatric assessment suggested that 52% of the patients had a formal psychotic diagnosis, 21% had personality disorder and 27% had taken an overdose in response to stress. The most frequently documented precipitating factors were family problems and disputes (37%). Unusually, the seasonal distribution in these patients suggested a peak in summer (37.5% of presentations) with lower numbers in spring (30.2%), autumn (17.7%) and winter (14.6%). Of the patients, 23.7% presented in July. A total of 73.5% of patients was conscious, 16.4% was somnolent, 4.5% was in precoma and 5.6% was in coma (GCS <8). Patients who received antidotal therapy comprised 17.9%. Evidence of hepatic dysfunction was observed in 8.9% of patients and renal dysfunction in 3.6%. Extracorporeal techniques for drug removal (hemodialysis and hemoperfusion) were used in 2.2% of patients. Intensive care therapy was required in 11.4% of patients. The mean overall hospitalization time was 3.3 days. The mortality rate was 2.9%.

CONCLUSIONS

This study shows that the epidemiology of self-harm by overdose in Greece is significantly different in terms of the seasonal presentation from other parts of Europe. The agents ingested and other features are similar to northern Europe. Psychiatric diagnoses are more common in our group than in those reported from northern Europe.

Psychoactive substances in suicides. Comparison of toxicologic findings in two samples

The goal in this study was to assess if there is any constancy in detections of psychoactive substances in consecutive suicides. Toxicologic findings in 179 suicides in San Diego County, California, between 1981 and 1982, and 333 suicides in Mobile County, Alabama, between 1990 and 1998, were compared. Alcohol was detected in about 30% of suicides in both samples. Abusable prescription psychoactive substances, i.e., benzodiazepines and opiates, were detected in one fifth of cases in both locations. Nonabusable prescription psychoactive substances, mainly antidepressants, were found in more suicides in Mobile than in San Diego. Detection rates of different classes of psychoactive substances have not changed much in the past decade. Detection of alcohol, cocaine, or cannabis in about 40% of suicides supports the clinical practice of discouraging consumption of these substances in depressed patients. Another challenge is the low rate of detection of antidepressants in suicide, which suggests undertreatment of depression in suicides. Continued reporting of routine, comprehensive, toxicologic findings in suicides is useful to monitor patterns of use of psychoactive substances in this group and to guide suicide prevention in clinical practice and public health policy.

Flumazenil use in an emergency department: a survey

OBJECTIVE

To evaluate the efficacy of flumazenil use by a one-year survey of practice in tan emergency department.

DESIGN

During a one-year period, an observational prospective study in the emergency department of an urban community hospital enrolled every patient admitted with a history of pure or mixed benzodiazepine acute poisoning. Case records were secondarily reviewed by an expert group. Actual flumazenil use during hospitalization was compared to currently recommended indications. In order to evaluate the efficacy of flumazenil use, patients who received flumazenil were matched with those who did not and effects on mortality, morbidity, number of costly procedures (CT scan, diagnostic toxicology, etc.) and duration of hospital stay were determined.

RESULTS

Of the 1529 patients admitted in 1 year for acute poisoning, 478 reportedly ingested at least one benzodiazepine. Twenty-nine patients (6%) received flumazenil in the emergency department whereas the expert reviewers recommended flumazenil use in only 18 (3.7%). In 11/29 (38%) cases, the use of fumazenil was considered inappropriate. The expert group considered flumazenil to be contraindicated in 93 of 478 patients. Nonetheless, flumazenil was used in 11 patients (rate of potentially harmful flumazenil use: 11/93; 12%), and a severe complication occurred in one of these patients after flumazenil. No significant difference could be shown in outcome, complication rate, number of complex procedures or duration of hospital stay between patients who received flumazenil and matched patients who did not.

CONCLUSION

The use of flumazenil in the clinical practice of an emergency department fails to show any beneficial effect in adult patients. Moreover, contraindications are frequently overlooked and this may expose patients to substantial risk of complications.

Different fatal toxicity of neuroleptics identified by autopsy

Autopsies and toxicological analyses at the Institute of Forensic Medicine revealed 85 fatal intoxications with neuroleptics in Vienna from 1991 to 1997. A total of 17 cases were linked to a single neuroleptic (NL) alone, while 68 deaths were attributed to a combination of NLs with other drugs. The most frequently detected agent was prothipendyl (n=41). During the study period the number of defined daily doses of high-potency NLs prescribed increased significantly (P< or =0.001) due to increased prescribing of new atypical antipsychotics. The quantity of intermediate- and low-potency NLs dispensed remained stable. The most frequently prescribed NL was haloperidol. The relative toxicities of different NLs were calculated by dividing the number of deaths caused by this NL into the number of defined daily doses prescribed in the observation period (f-value). Single-substance intoxications and multiple-substance intoxications were distinguished. The highest f-values were associated with low-potency NLs, especially with prothipendyl, chlorprothixene and levomepromazine. Low f-values were found for the group of high-potency NLs, including flupentixol, fluphenazine, haloperidol and pimozide, as well as olanzapine. Compared to the f-values for all NLs prescribed, f-values for low-potency NLs were shown to be significantly higher concerning single-substance intoxications (P< or = 0.05) and multiple-substance intoxications (P < or = 0.001), while f-values for high-potency NLs were significantly lower (P< or = 0.05 and P< or = 0.001). We are not aware of the psychiatric diagnoses in our post-mortem sample. However, the present results indicate that careless use of low-potent NLs should be avoided in patients with a potential risk of accidental or suicidal overdose.

Limitations on the use of benzodiazepines in anxiety and insomnia: are they justified?

The benzodiazepines are still extensively used in psychiatry, neurology and medicine in general. Anxiety disorder and severe insomnia are important syndromal indications, but these drugs are widely prescribed at the symptomatic level, resulting in potential overuse. The official data sheets recommend short durations of usage and conservative dosage. Although short-term efficacy is established, long-term efficacy remains controversial, as relevant data are scanty and relapse, rebound and dependence on withdrawal not clearly distinguished. The risks of the benzodiazepines are well-documented and comprise psychological and physical effects. Among the former are subjective sedation, paradoxical release of anxiety and/or hostility, psychomotor impairment, memory disruption, and risks of accidents. Physical effects include vertigo, dysarthria, ataxia with falls, especially in the elderly. Dependence can supervene on long-term use, occasionally with dose escalation. The benzodiazepines are now recognised as major drugs of abuse and addiction. Other drug and non-drug therapies are available and have a superior risk benefit ratio in long-term use. It is concluded that benzodiazepines should be reserved for short-term use--up to 4 weeks--and in conservative dosage.

Diazepam reduces action potential duration in guinea-pig papillary muscle by a cAMP-dependent mechanism

In this study, we have analyzed the role of cyclic AMP (cAMP) as the mediator of the decrease in action potential duration induced by diazepam. Diazepam (1-100 microM) reduced, in a dose-dependent manner, the duration of intracellular action potential recorded in the papillary muscle obtained from the right ventricle of the guinea pig heart. This effect was mimicked by the analog of cyclic AMP, 8-Br-cAMP (100 microM), but not by gamma-amino-butyric acid (GABA). Also, the selective antagonist of the benzodiazepine receptors, flumazenil did not modify the effect of diazepam. The diazepam-induced shortening of action potential duration was partially antagonized by the inhibitor of cAMP synthesis carbachol (1 microM) or the blocker of the cAMP-dependent protein kinase A, Rp-cAMP[S] (1 microM). These results indicate that cyclic AMP is involved in the diazepam-induced shortening of the action potential duration of the guinea pig papillary muscle.

Flumazenil in drug overdose: randomized, placebo-controlled study to assess cost effectiveness

OBJECTIVE

To investigate cost effectiveness of administration of flumazenil to patients presenting with suspected acute drug overdose.

DESIGN

Double-blind, prospective, placebo-controlled randomized study.

SETTING

University teaching hospital.

PATIENTS

Forty-three adults presenting with suspected drug overdose and having a Glasgow Coma Scale (GCS) score of <13. Patients with known benzodiazepine/tricyclic ingestion were excluded.

INTERVENTIONS

Intravenous administration of flumazenil (up to 2 mg) or placebo.

MEASUREMENTS AND MAIN RESULTS

Individual patient costs were assessed and data aggregated for each treatment group. Major diagnostic and therapeutic interventions were recorded and between group comparisons performed. Clinical response to study drug administration was assessed by obtaining pre- and post-drug GCS scores and observation of the patient for at least 180 mins for signs of resedation. Aggregate cost or number of major diagnostic and therapeutic interventions were not different between groups. Patients randomized to the flumazenil group showed a marked increase in GCS score (7.4 to 11.8) compared with those in the placebo group (8.2 to 8.6).

CONCLUSION

Use of flumazenil in intentional drug overdose of unknown etiology is not cost effective.

Use and abuse of the benzodiazepines

Since chlordiazepoxide was introduced in 1961, the benzodiazepines have had many important roles in the pharmacotherapy of various disorders. This drug class for the central nervous system has been considered one of the safest in use for 35 years, especially when the benzodiazepines are compared with the barbiturates they often replaced. The objective of this article is to provide an update on the availability and distribution of benzodiazepines around the world and to discuss their most common clinical applications. Adverse effects of benzodiazepines, observed after long-term therapeutic use and after overdoses, are also presented. Triazolam is discussed because this benzodiazepine was removed from the market by regulatory authorities in the United Kingdom in 1991. Benzodiazepines will continue to have an important role in clinical medicine. Their clinical use, however, should be monitored more closely because of the greater awareness of their adverse effects after long-term use and because of the potential for misuse and abuse.

Poisoning and epidemiology: 'toxicoepidemiology'

1. There is little hypothesis-testing clinical research performed in toxicology. Randomized clinical trials are rare and most observational studies are performed on highly selected patients and are subject to marked bias. Thus, for many poisonings, our approach has been based almost entirely on deduction from known pharmacological/toxicological effects, generalizations from drugs within the same therapeutic class, animal data and case reports. This is also far from satisfactory, as many toxicological mechanisms are poorly understood and not related to the therapeutic class. 2. Although we need much better data to address the clinical and public health aspects of poisoning, there are many practical and ethical reasons why randomized clinical trials are difficult in this field. However, the scope for observational research, in particular population-based clinical epidemiology, is almost unlimited. The collection of data on human poisoning is facilitated because most non-fatal overdoses are admitted to hospital and by legal requirements to report to the coroner deaths that are due to poisoning. In the present article I argue that 'toxicoepidemiology', meaning the application of epidemiological methods to the problem of acute poisoning, is the best means we have of addressing deficiencies in our knowledge of poisoning. 3. Examples are given of a variety of observational research strategies, ranging from audit to meta-analysis, that may be applied to clinical toxicology. From coronial and clinical data obtained from reasonably well-defined populations, it has been possible to identify a number of previously unrecognized differences in the severity and spectrum of toxicity between and within drug classes. Also, the demographic risk factors for poisoning and the reproducibility, validity and optimal use of diagnostic and therapeutic interventions can be assessed. 4. The major limitations to the range of associations and interventions that may be studied are the need to achieve adequate power to study uncommon outcomes or poisonings and the ability to replicate findings at other centres using similar methodology. The expansion of data collection to other centres has the potential largely to overcome these obstacles.

Recreational drug users in the ICU: a review

The purpose of this paper is to examine why patients who use recreational drugs which depress the central nervous system might experience such severe difficulties that they require an admission to an Intensive Care Unit (ICU). The specific problems each substance may cause will be examined, as will the problems common to all. In conclusion, there is a brief discussion of some of the social, educational and management issues that drug victims present.

Screening for drugs of abuse (II): Cannabinoids, lysergic acid diethylamide, buprenorphine, methadone, barbiturates, benzodiazepines and other drugs

Requirements for the provision of an efficient and reliable service for drugs of abuse screening in urine have been summarized in Part I of this review. The requirements included rapid turn-around times, good communications between requesting clinicians and the laboratory, and participation in quality assessment schemes. In addition, the need for checking/confirmation of positive results obtained for preliminary screening methods was stressed. This aspect of the service has assumed even greater importance with widespread use of dip-stick technology and the increasing number of reasons for which drug screening is performed. Many of these additional uses of drug screening have possible serious legal implications, for example, screening school pupils, professional footballers, parents involved in child custody cases, persons applying for renewal of a driving licence after disqualification for a drug-related offence, doctors seeking re-registration after removal for drug abuse, and checking for compliance with terms of probation orders; as well as pre-employment screening and work-place testing. In many cases these requests will be received from a general practitioner or drug clinic with no indication of the reason for which testing has been requested. This also raises the serious problems of a chain of custody, provision of two samples, stability of samples, and secure and lengthy storage of samples in the laboratory-samples may be requested by legal authorities several months after the initial testing. The need for confirmation of positive results is now widely accepted but it may be equally important to confirm unexpected negative results. Failure to detect the presence of maintenance drugs may lead to the patient being discharged from a drug treatment clinic and, if attendance at the clinic is one of the terms of continued employment, to dismissal. It seems likely that increasing abuse of drugs and the efforts of regulatory authorities to control this, will lead to the manufacture of more designer drugs. Production of substituted phenethylamines was facilitated by the drug makers' cook book, 'PIHKAL' (Phenethylamines I Have Known And Loved) by Dr Alexander Shulgin and Ann Shulgin, and production of substituted tryptamines is promised in their next book, TIHKAL. Looking to the future, laboratories will need to ensure that they can detect and quantitate an ever-increasing number of drugs and related substances. The question of confidence in results of drugs of abuse testing raised in 1993 by Watson has assumed even greater importance as a result of attention focused on the OJ Simpson trial in Los Angeles. Toxicological investigations are likely to be challenged more frequently in the future. Even if analyses have been performed by GC-MS, there is a need to establish the level of match between the spectrum of the unknown substance and a library spectrum which is considered acceptable for legal purposes. It will also be essential to ensure that computer libraries contain spectra for all substances likely to be encountered in drugs of abuse screening.

Abuse liability of flunitrazepam

Flunitrazepam is among the most frequently prescribed hypnotics in many countries. Although it was never marketed in the United States, flunitrazepam, in recent years, has been smuggled into the country, and reports of abuse--including alleged use of the drug to facilitate "date rape"--have attracted a great deal of scrutiny. It has been suggested that flunitrazepam may have greater liability for abuse than other benzodiazepines; such suggestions are supported by surveys of opioid abusers, many of whom report a distinct preference for flunitrazepam over other benzodiazepines. Experimental studies of animals and normal human subjects indicate that, although flunitrazepam has high efficacy and is very potent, it is pharmacologically similar to most other benzodiazepines. Although the studies are limited in number and scope, the data show no apparent differences between flunitrazepam and other benzodiazepines in ability to produce drug-taking or drug-seeking behavior, in capacity to produce physiologic dependence, nor in the characteristics of withdrawal after administration of an antagonist or discontinuation of treatment. Similar to other benzodiazepines, flunitrazepam produces dose-dependent effects on psychomotor performance and recall. Flunitrazepam does not seem to be involved in medical emergencies more often than other benzodiazepines, and there is no indication that flunitrazepam is more toxic than other benzodiazepines when taken in overdose by drug abusers or other individuals. Survey research among typical patient populations suggests that flunitrazepam is characteristic of benzodiazepines in that it is used appropriately and conservatively, with low liability for abuse. Thus the reported preference for flunitrazepam among opioid abusers seems to be the only way in which flunitrazepam is distinguished from other benzodiazepines; it is unclear what characteristics of the drug may be responsible for this reported preference. The evidence considered in this review indicates that abuse of flunitrazepam in this special population is not associated with any distinctive threats to the health of the general public.

Drugs taken in fatal and non-fatal self-poisoning: a study in south London

This study compared the number and type of substances taken in deliberate self-poisoning with fatal (n = 127) and non-fatal (n = 521) outcome. The aims were (i) to describe substances typically involved in self-poisoning in England and Wales, (ii) to examine the role of drug "cocktails' and (iii) to examine whether toxic substances are over-represented in cases with fatal outcome. Over-the-counter (OTC) analgesics, minor tranquillizers and antidepressants accounted for about 70% of substances taken, irrespective of outcome. Compared with survivors, cases who died had taken a higher mean number of substances. Among self-poisonings with a single substance, antidepressants and paracetamol-opiate combinations were over-represented in fatal-outcome cases. This report emphasizes the role of OTC analgesics and antidepressants in overdose-related mortality in England and Wales.

Sudden death and benzodiazepines

A study of 16 deaths associated with toxic concentrations of benzodiazepines during the period of 5 years leading up to July 1994 is presented. Cases where other drugs, including ethanol, had contributed to the death were excluded. All cases were subject to a full macroscopic and microscopic examination by pathologists, and all cases were subject to a full toxicological work-up. Preexisting natural disease was a feature of 11 cases. In the remaining five cases, death was caused solely by benzodiazepines. There were 14 suicides. Nitrazepam and temazepam were the most prevalent drugs detected, followed by oxazepam and flunitrazepam. Minimum toxic femoral blood concentrations of 7-aminonitrazepam, 7-aminoflunitrazepam, and oxazepam were estimated as 0.5, 0.2, and 2 mg/L, respectively. Relating these deaths to prescription rates in Victoria suggest that flunitrazepam may be inherently more toxic if misused than other benzodiazepines currently available on the Australian market.

Parasuicide in Pakistan: experience at a university hospital

There have been few reports of parasuicide from Pakistan, where the act is considered to be a criminal offence and the Islamic religion strongly disapproves of it. In order to address the problem, a retrospective case report analysis of all index cases of parasuicide presenting over a period of 3.5 years to a university hospital in Karachi, Pakistan, was undertaken. Our results showed that most of the subjects were young adults, with married women representing the single largest group. Self-poisoning with medication was the most common method, and benzodiazepines the most frequently used drug. Interpersonal conflict with the opposite sex was the most common precipitating cause. In Pakistani culture, marriage appears to be a significant source of stress for women. Reports based on official police records do not reflect the true picture of the problem in Pakistan.

An analysis of age and gender influences on the relative risk for suicide and psychotropic drug self-poisoning

Psychiatric illness is a significant risk factor for both attempted and completed suicide and psychotropic medications account for 80% of all drug overdoses involving prescription medications. One challenge facing clinicians is to balance the benefit of treatment against the risk of drug overdose. The aim of the present study was to compare the age and gender distribution of patients prescribed psychotropic drugs with patients attempting and completing suicide with these drugs. Data were obtained from the Australian census and studies of general practitioner prescribing, patients who committed suicide or presented with self-poisoning within a defined geographic area. The characteristics of these populations were compared to calculate odds ratios for attempting or completing suicide with psychotropic drugs, before and after correction for rates of prescription, in different age and gender groups. The odds ratios (ORs) for self-poisoning were higher for those aged less than 45 years and yet this group was least likely to be prescribed psychotropic drugs. Men had a much higher rate of completed suicide using more lethal methods. The ORs for self-poisoning and suicide with psychotropic drugs, after correction for prescription rates, for those aged 15 to 24 years were 11.1 and 1.7, respectively. Those aged 25 to 44 years had ORs of 4.9 and 4.3, and, by contrast, those over 75 years had ORs of 0.03 and 0. Women were slightly more likely to poison themselves with psychotropic drugs (OR 1.2). However, the situation reversed after correction for prescription rates (OR 0.69). It is concluded that greater caution should be exercised in prescribing for those under 45 years of age, given their relatively higher risk of drug overdose, and that the least toxic compounds should be used. The risk (of self-poisoning) among the elderly may have been overstated, so that some patients may have been denied the benefit of adequate treatment.

Relative toxicity of benzodiazepines in overdose

OBJECTIVE

To assess the sedative effects in overdose of temazepam and oxazepam compared with other benzodiazepines to determine if this explains reported differences in fatal toxicity.

DESIGN

Cohort study of patients admitted with benzodiazepine poisoning.

SETTING

Newcastle, Australia.

SUBJECTS

303 patients who had ingested benzodiazepine alone or in combination with alcohol and presented to a general hospital which served a well defined geographical area.

MAIN OUTCOME MEASURES

Degree of sedation: Glasgow coma score, McCarron Score, and whether patients were stuporose or comatose.

RESULTS

Oxazepam produced less and temazepam more sedation than other benzodiazepines. Unadjusted odds ratios for coma with oxazepam and temazepam compared with other benzodiazepines were 0.0 (95% confidence interval 0.0 to 0.85) and 1.86 (0.68 to 4.77) respectively, chi 2 = 7.08, 2df, P = 0.03. After adjustment for potentially confounding effects of age, dose ingested, and coingestion of alcohol, the odds ratios were 0.22 (0.0 to 1.43) for oxazepam and 1.94 (0.57 to 6.23) for temazepam. Similar results were obtained for other measures of sedation.

CONCLUSIONS

These results were in accordance with fatal toxicity indices derived from coroners' data on mortality and rates of prescription. The relative safety of benzodiazepines in overdose should be a consideration when they are prescribed.

Cardiotoxicity more common in thioridazine overdose than with other neuroleptics

On the basis of case reports and small non-comparative series it has been suggested that thioridazine has greater cardiotoxicity in overdose. Limited evidence also suggests an increased association with sudden death in therapeutic doses. The aim of our study is to examine the clinical and electrocardiographic features associated with neuroleptic poisoning and compare thioridazine with other neuroleptics. Consecutive adult patients with neuroleptic poisoning presenting to metropolitan hospitals in Newcastle between 1987 and 1993 were studied. The main outcome measures examined were ECG changes (QRS, QT and QTc intervals), arrhythmias, seizures, degree of sedation, heart rate and blood pressure. Two-hundred ninety-nine patients had ingested thioridazine (104), chlorpromazine (69), trifluoperazine (36), pericyazine (35), haloperidol (33), prochlorperazine (18), fluphenazine (8), or other neuroleptics (7). Sixteen patients had ingested more than one neuroleptic and were excluded from comparative analysis. Thioridazine was more likely to cause tachycardia (odds ratio 1.7, 95% CI 1.1-2.9, p = 0.03), a prolonged QT interval (odds ratio 5.2, 95% CI 1.6-17.1, p = 0.006), prolonged QTc > 450 ms1/2 (odds ratio 4.7, 95% CI 2.7-7.9, p = 0.001), a widened QRS (> 100 ms) (odds ratio 3.1, 95% CI 1.5-6.3, p = 0.001) and arrhythmias (odds ratio infinity, 95% CI 2.4- infinity, p = 0.004). There were no significant differences in the odds of coma (odds ratio 0.5 (0.2-1.5)), hypotension (odds ratio 0.9 (0.4-1.9)) or seizures (odds ratio 3.9 (0.3-43.5)). Adjustment for age, sex, dose ingested and co-ingestion of tricyclic antidepressants or lithium had no major effect on the odds ratios observed.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of the drugs taken in fatal and nonfatal self-poisoning

The objective of this study was a) to compare patterns of drug use in fatal and nonfatal overdoses and b) to find out if toxic drugs are overrepresented in overdoses with fatal outcome. A total of 179 cases of fatal overdoses in Switzerland (population 6.6 million) were compared with 269 medically treated self-poisoners from the agglomeration of Berne (population 301,630). Because of frequent multiple drug use, all the different compounds taken singly or in combination with other drugs were recorded and grouped according to drug types. The patterns of the frequencies of drugs used were remarkably similar in both groups. The majority of the drugs were psychotropics (81% in fatal and 68% in nonfatal overdose). Twenty-nine completed suicides were the result of drug combinations specifically recommended by EXIT. In the remaining cases benzodiazepines were used most frequently in both attempted and completed suicide, often in combination with other drugs or alcohol. Barbiturates were the only drugs recorded significantly more often in fatal overdoses (9% vs 3%). No significant difference was found for tricyclic antidepressants (13% vs 10%), or other types of drugs. The results are consistent with our assumption that drugs with higher toxicity would be overrepresented in overdoses with fatal outcome. Barbiturates, which are well known to be dangerous in overdose, were clearly associated with fatal overdoses, but not tricyclic antidepressants. This, in our view, suggests that the risk of prescribing tricyclic antidepressants should not be overestimated. The frequent use of benzodiazepines in completed suicide, however, indicates that there are no truly safe drugs in overdose.