Relative toxicity of benzodiazepines in overdose

Benzodiazepine analysis by an improved LC-MS/MS method illustrates usage patterns in Washington State

BACKGROUND

The standard approach for benzodiazepine detection often includes immunoassay followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The illicit use of non-prescribed benzodiazepines has been trending up nationally.

METHODS

We developed and validated an improved LC-MS/MS assay for benzodiazepine detection in urine. We expanded the testing panel by adding five drugs to the previous panel of ten. We determined the prevalence of individual benzodiazepines in our patient population. Immunoassay results were compared with LC-MS/MS to evaluate assay performance.

RESULTS

Clonazepam and alprazolam were the most common benzodiazepines present. Etizolam and flualprazolam were also prevalent in Washington State. Compared with the LC-MS/MS assay, the immunoassay had variable cross-reactivity, which explained false negative and false positive immunoassay results. The inclusion of new drugs in the LC-MS/MS panel significantly reduced the incidence of immunoassay results interpreted as falsely positive.

CONCLUSION

New illicit benzodiazepines have emerged regionally and nationally. The inclusion of novel drugs in LC-MS/MS assay was helpful in properly characterizing the epidemiology of benzodiazepine use in our patient population. This information will lead to better assay result interpretations and patient care, and our experiences provide a roadmap for other clinical laboratories looking to expand their testing menu or transition to new instrumentation.

Relationship between clock gene expression and CYP2C19 and CYP3A4 with benzodiazepines

The present study aimed to clarify the expressions and roles of clock genes involved in drug metabolism in patients taking benzodiazepines (BZDs), as well as the drug metabolism regulators controlled by clock genes for each BZD type. The relationships between the expressions of the clock genes BMAL1, PER2, and DBP and the drug-metabolizing enzymes CYP3A4 and CYP2C19 were investigated using livers from BZD-detected autopsy cases. In addition, the effect of BZD exposure on various genes was examined in HepG2 human hepatocellular carcinoma cells. The expressions of DBP, CYP3A4, and CYP2C19 in the liver were lower in the diazepam-detected group than in the non-detected group. Furthermore, BMAL1 expression correlated with CYP2C19 expression. Cell culture experiments showed that the expressions of DBP and CYP3A4 decreased, whereas those of BMAL1 and CYP2C19 increased after diazepam and midazolam exposure. The results of the analyses of autopsy samples and cultured cells suggested that DBP regulates CYP3A4 when exposed to BZD. Understanding the relationship between these clock genes and CYPs may help achieve individualized drug therapy.

Strategies for the treatment of acute benzodiazepine toxicity in a clinical setting: the role of antidotes

INTRODUCTION

Although not a potentially life-threatening poisoning, benzodiazepine (BZD) intoxication may be life-threatening in special situations/populations or those with background diseases.

AREAS COVERED

The aim of this review is to evaluate all possible treatment options available in the literature for the management of benzodiazepine poisoning with special attention to antidote administration. We conducted a literature search using PubMed, Google Scholar, EMBASE, and Cochrane central register from 1 January 1980 to 10 November 2021 using keywords 'benzodiazepine,' 'poisoning,' 'toxicity,' 'intoxication,' and 'treatment.'

EXPERT OPINION

Careful patient selection, ideally by a clinical toxicologist, may decrease the complications of flumazenil and add to its efficacy. The cost-to-benefit ratio should be considered in every single patient who is a candidate for flumazenil administration. In case a decision has been made to administer flumazenil, careful consideration of the possible contraindications is essential. We recommend slow administration of low doses of flumazenil (0.1 mg/minute) to avoid complications or withhold the administration with development of first signs of adverse effects. The main treatment of benzodiazepine toxicity is conservative with administration of activated charcoal, monitoring of the vital signs, prevention of aspiration and development of deep vein thrombosis due to prolonged immobilization, and respiratory support.

Influence of Internal Structure of the Sorbents on Diazepam Sorption from Simulated Intestinal Fluid

The capacity of natural Na-montmorillonite and activated charcoal for sorption of diazepam from simulated intestinal fluid (SIF) was studied. The main characteristics of the sorbents were determined. In order to characterize the sorption process of diazepam the influence of the pH, contact time and ethanol presence in SIF was analyzed. Adsorption isotherms for the diazepam-activated charcoal and diazepam-natural Na-montmorillonite systems were determined. The Langmuir isotherm model provided a very good description of diazepam sorption. Furthermore, the pH-drift method was used to determine the specific pH at zero point of charge (pHzpc) of the sorbents. The obtained results show that the internal structure of the sorbents and pH of the SIF solutions are very important for diazepam sorption. Both the surface of the activated charcoal and natural Na-montmorillonite are positively charged below the pHzpc so the sorption of diazepam is higher below this point and occur by van der Waals forces. The presence of ethanol in simulated intestinal fluid lowers the adsorption of diazepam on both sorbents.

Toxicological Analysis Unveiling the Low Rate of Self-Reporting of Addictive/Recreative Substances in Acute Severe Drug Overdose Cases

OBJECTIVE

Toxicological analysis (TA) is advised when assessing the prognosis and the treatment of drug overdose patients. Apart from this use, the value of TA has remained unclear. This study aimed at defining the value of TA regarding the toxicological diagnosis in severe overdose cases that involved addictive or recreational drugs (ARDs) that were used either alone or in combination with medicinal drugs.

METHODS

The patients who were enrolled in the study had been admitted to our intensive care unit for the treatment of poisoning. TA was performed using advanced technologies such as mass spectrometry of blood/urine on admission. An occurrence indicated the supposed ingestion of a defined substance. Patients were included in a group depending on the combination of the occurrences of supposed ingested drugs (SID) and the results of the 1) TA: SID+, TA+; 2) SID+, not searched by TA; 3) SID-, TA+.

RESULTS

There were 224 occurrences of 90 substances in 70 patients. ARDs were present in 30 patients (43%). ARD accounted for 24 occurrences in the SID+, TA+ group, 10 occurrences in the SID+, not searched group and 196 occurrences in the SID-, TA+ group. In the SID+, TA+ group, 9 occurrences (69%) of ethanol were confirmed by TA. Ingestion of ethanol was invalidated in 4 occurrences (31%). In the patients who denied ethanol ingestion, TA confirmed the non-ingestion of ethanol using 30 blood measures (81%). Ethanol was involved in 57% of the patients, being the lone substance in only 1 case.

CONCLUSION

In drug overdose instances that result in organ failure(s) and involve ARDs, self-reporting is of limited value in assessing the patients' exposure to ARD. Multiple consumptions expose patients to unexpected drug interactions.

Association between suicide death and concordance with benzodiazepine treatment guidelines for anxiety and sleep disorders

OBJECTIVE

Guidelines for management of anxiety and sleep disorders emphasize antidepressant medications and/or psychotherapy as first/second-line and benzodiazepines as third-line treatments. We evaluated the association between suicide death and concordance with benzodiazepine guidelines.

METHODS

Retrospective case-control study of patients with anxiety and/or sleep disorders from health systems across 8 U.S. states within the Mental Health Research Network. Suicide death cases were matched to controls on year and health system. Appropriate benzodiazepine prescribing defined as: no monotherapy, no long duration, and/or age < 65 years. The association between guideline concordance and suicide death was evaluated, adjusting for diagnostic and treatment covariates.

RESULTS

Sample included 6960 patients with anxiety disorders (2363 filled benzodiazepine) and 6215 with sleep disorders (1237 filled benzodiazepine). Benzodiazepine guideline concordance was associated with reduced odds for suicide in patients with anxiety disorders (OR = 0.611, 95% CI = 0.392-0.953, p = 0.03) and was driven by shorter duration of benzodiazepine use with concomitant psychotherapy or antidepressant medication. The association of benzodiazepine guideline concordance with suicide death did not meet statistical significance in the sleep disorder group (OR = 0.413, 95% CI = 0.154-1.11, p = 0.08).

CONCLUSIONS

We found reduced odds for suicide in those with anxiety disorders who filled benzodiazepines in short-moderate duration with concomitant psychotherapy or antidepressant treatment.

The Effect of Methylphenidate on Reed Scaling in Benzodiazepine Poisoning: A Prospective Trial

BACKGROUND

Benzodiazepine is one of the most important causes of substance abuse and intoxication throughout the world and Iran.

OBJECTIVE

The aim of our study is to determine the role of stimulants in reversing CNS level in acute Benzodiazepine poisoning patients who were hospitalized at referral poison center.

METHOD

This was a randomized double-blind placebo-controlled trial study on 32 cases with pure acute Benzodiazepine poisoning from March 2016 to February 2017. Diagnosis of pure acute poisoning was based on history, and laboratory confirmation. We gathered the demographics, clinical data, laboratory data, hospitalization and outcome. Participants were randomized into two groups: Methylphenidate Group (MPH) and Placebo Group (PBO).

RESULTS

The randomized sample consisted of 32 participants who were predominately female (83%). The majority of the PBO group and the MPH group reported improvement in their consciousness with a significant difference between the two groups (p = .005). Paired sample t-test analyses on Reed Scale data revealed an increase in the probability of improvement during the trial for the MPH group compared to the PBO group. Furthermore, the HCo3 (bicarbonate) level has a significant p-value with respect to age groups (p = .02). None of our cases required either the ICU facility or intubation.

CONCLUSION

Our study provided the MPH superiority over PBO in reversing CNS symptoms in loss of consciousness in acute BZD poisoned patients. Thus, this trial provides concrete evidence that improvement in consciousness levels (Reed Scale rated) among those patients receiving MPH was associated with a methylphenidate use.

The relative lethal toxicity of pharmaceutical and illicit substances: A 16-year study of the Greater Newcastle Hunter Area, Australia

AIMS

We aim to calculate 2 metrics of relative lethal toxicity; the fatal toxicity index (FTI; number of deaths per year of a daily dose) and the case fatality (CF; number of deaths per overdose) with a focus on opioids, antidepressants, antipsychotics, benzodiazepines and illicit drugs.

METHODS

This descriptive cohort study used the Australian National Coronial Information System (NCIS) to identify a population of individuals with drug-associated deaths in the Greater Newcastle Hunter Area between January 2002 and December 2016. This was combined with Australian medicine dispensing data and corresponding data from the Hunter Area Toxicology Service to calculate FTI and CF.

RESULTS

There were 444 drug-related deaths and 21,296 overdoses during the study period. FTI and CF were well correlated (Spearman's rho 0.64, P < .001). Of the classes of interest, opioids had the highest FTI (40.3 95% confidence interval [CI] 35.2-45.4 deaths per 100 years of use at the defined daily dose or deaths/DDD/100 years) and CF (12.4% 95%CI 11.0-13.9). Fentanyl, methadone and morphine had the highest relative fatal toxicity within this class. Tricyclic antidepressants had the highest relative fatal toxicity of all antidepressants (FTI 14.5 95%CI 9.7-19.3 deaths/DDD/100 years and CF 7.1% [95%CI 4.8-9.3]) and benzodiazepines appeared to be more associated with multiple agent deaths than single. Of the illicit drugs, heroin had the highest CF (26.4%, 95%CI 19.1-33.7).

CONCLUSION

Knowledge of relative lethal toxicity is useful to prescribers and medicines and public health policy makers in restricting access to more toxic drugs and may also assist coroners in determining cause of death.

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.

Investigating the Interaction Between Sleep Symptoms of Arousal and Acquired Capability in Predicting Suicidality

Heightened arousal significantly interacts with acquired capability to predict suicidality. We explore this interaction with insomnia and nightmares independently of waking state arousal symptoms, and test predictions of the Interpersonal Theory of Suicide (IPTS) and Escape Theory in relation to these sleep arousal symptoms. Findings from our e-survey (n = 540) supported the IPTS over models of Suicide as Escape. Sleep-specific measurements of arousal (insomnia and nightmares) showed no main effect, yet interacted with acquired capability to predict increased suicidality. The explained variance in suicidality by the interaction (1%-2%) using sleep-specific measures was comparable to variance explained by interactions previously reported in the literature using measurements composed of a mix of waking and sleep state arousal symptoms. Similarly, when entrapment (inability to escape) was included in models, main effects of sleep symptoms arousal were not detected yet interacted with entrapment to predict suicidality. We discuss findings in relation to treatment options suggesting that sleep-specific interventions be considered for the long-term management of at-risk individuals.

Toxicodynetics: A new discipline in clinical toxicology

OBJECTIVES

Regarding the different disciplines that encompass the pharmacology and the toxicology, none is specifically dedicated to the description and analysis of the time-course of relevant toxic effects both in experimental and clinical studies. The lack of a discipline devoted to this major field in toxicology results in misconception and even in errors by clinicians.

MATERIAL AND METHODS

Review of the basic different disciplines that encompass pharmacology toxicology and comparing with the description of the time-course of effects in conditions in which toxicological analysis was not performed or with limited analytical evidence.

RESULTS

Review of the literature clearly shows how misleading is the current extrapolation of toxicokinetic data to the description of the time-course of toxic effects.

CONCLUSION

A new discipline entitled toxicodynetics should be developed aiming at a more systematic description of the time-course of effects in acute human and experimental poisonings. Toxicodynetics might help emergency physicians in risk assessment when facing a poisoning and contribute to a better assessment of quality control of data collected by poison control centres. Toxicodynetics would also allow a quantitative approach to the clinical effects resulting from drug-drug interaction.

A Longitudinal Study of Multiple Drug Use and Overdose Among Young People Who Inject Drugs

OBJECTIVES

To determine the association between multiple drug use and nonfatal overdose among young people (younger than 30 years) who inject drugs.

METHODS

We completed a longitudinal study of 173 injection drug users younger than 30 years living in San Francisco, California, between April 2012 and February 2014.

RESULTS

The odds of nonfatal overdose increased significantly as heroin and benzodiazepine pill-taking days increased and when alcohol consumption exceeded 10 drinks per day compared with 0 drinks per day.

CONCLUSIONS

Heroin, benzodiazepine, and alcohol use were independently associated with nonfatal overdose over time among young people who inject drugs. Efforts to address multiple central nervous system depressant use remain an important component of a comprehensive approach to overdose, particularly among young people.

A prospective cohort study of trends in self-poisoning, Newcastle, Australia, 1987-2012: plus ça change, plus c'est la même chose

OBJECTIVE

To examine inhospital mortality and morbidity associated with self-poisoning with different drug classes over an extended period.

DESIGN, SETTING AND PARTICIPANTS

A prospective cohort study over 26 years (1987-2012) with limited follow-up of patients presenting consecutively to a primary and tertiary referral toxicology centre covering Newcastle, Lake Macquarie and Port Stephens, Australia.

MAIN OUTCOME MEASURES

Hospital length of stay, types of drugs ingested, intensive care unit (ICU) admission, requirement for ventilation, inhospital deaths and rates of antidepressant drug use in Australia.

RESULTS

Over the study period, there were 17 266 admissions of patients poisoned by 34 342 substances (16 723 drugs available only on prescription). The median length of stay was 16 hours, 12.2% of patients (2101/17 266) were admitted to an ICU, 7.4% (1281/17 266) were ventilated and 78 (0.45%) died in hospital. Patient demographics, social and psychiatric factors remained stable over the 26-year period, but case fatality decreased (from 0.77% [15/1955] to 0.17% [7/4060]) as did ICU admissions (19.2% [376/1955] to 6.9% [280/4060]), ventilation (13.7% [268/1955] to 4.8% [193/4060]) and LOS. The most frequently ingested substances were alcohol, benzodiazepines, paracetamol, antidepressants and antipsychotics. There was a substantial fall in some highly toxic drugs (tricyclic antidepressants, barbiturates, conventional antipsychotics and theophylline), but increases in less toxic selective serotonin reuptake inhibitors, serotonin-noradrenaline reuptake inhibitors and paracetamol. A greater than sixfold increase in community antidepressant use was accompanied by only minor changes in overall and antidepressant self-poisoning rates.

CONCLUSION

Over two decades, there were decreases in poisonings by many highly toxic drugs which were associated with substantial reductions in morbidity and inhospital deaths. Despite massive increases in the number of antidepressant prescriptions, neither rates of self-harm nor the proportion of antidepressant poisonings increased markedly.

Benzodiazepine prescribing patterns and deaths from drug overdose among US veterans receiving opioid analgesics: case-cohort study

OBJECTIVE

To study the association between benzodiazepine prescribing patterns including dose, type, and dosing schedule and the risk of death from drug overdose among US veterans receiving opioid analgesics.

DESIGN

Case-cohort study.

SETTING

Veterans Health Administration (VHA), 2004-09.

PARTICIPANTS

US veterans, primarily male, who received opioid analgesics in 2004-09. All veterans who died from a drug overdose (n=2400) while receiving opioid analgesics and a random sample of veterans (n=420,386) who received VHA medical services and opioid analgesics.

MAIN OUTCOME MEASURE

Death from drug overdose, defined as any intentional, unintentional, or indeterminate death from poisoning caused by any drug, determined by information on cause of death from the National Death Index.

RESULTS

During the study period 27% (n=112,069) of veterans who received opioid analgesics also received benzodiazepines. About half of the deaths from drug overdose (n=1185) occurred when veterans were concurrently prescribed benzodiazepines and opioids. Risk of death from drug overdose increased with history of benzodiazepine prescription: adjusted hazard ratios were 2.33 (95% confidence interval 2.05 to 2.64) for former prescriptions versus no prescription and 3.86 (3.49 to 4.26) for current prescriptions versus no prescription. Risk of death from drug overdose increased as daily benzodiazepine dose increased. Compared with clonazepam, temazepam was associated with a decreased risk of death from drug overdose (0.63, 0.48 to 0.82). Benzodiazepine dosing schedule was not associated with risk of death from drug overdose.

CONCLUSIONS

Among veterans receiving opioid analgesics, receipt of benzodiazepines was associated with an increased risk of death from drug overdose in a dose-response fashion.

Benzodiazepines

The misuse and abuse of prescription medications in the United States continues to increase despite interventions by health care professionals, regulatory, and law enforcement agencies. Opioid analgesics are the leading class of prescription drugs that have caused unintentional overdose deaths. Benzodiazepines when taken alone are relatively safe agents in overdose. However, a 5-fold increase in deaths attributed to benzodiazepines occurred from 1999 to 2009. Emergency department visits related to opioid analgesics increased by 111% followed by benzodiazepines 89%. During 2003 to 2009, the 2 prescriptions drugs with the highest increase in death rates were oxycodone 264.6% and alprazolam 233.8%. Therefore, benzodiazepines have a significant impact on prescription drug unintentional overdoses second only to the opioid analgesics. The combination prescribing of benzodiazepines and opioid analgesics commonly takes place. The pharmacokinetic drug interactions between benzodiazepines and opioid analgesics are complex. The pharmacodynamic actions of these agents differ as their combined effects produce significant respiratory depression. Physician and pharmacy shopping by patients occurs, and prescription drug-monitoring programs can provide important information on benzodiazepine and opioid analgesic prescribing patterns and patient usage. Health care professionals need to inform patients and work closely with regulatory agencies and legislatures to stem the increasing fatalities from prescription drug unintentional overdoses.

Understanding the pharmacokinetics of anxiolytic drugs

INTRODUCTION

Anxiety disorders are considered the most common mental disorders and they can increase the risk for comorbid mood and substance use disorders, significantly contributing to the global burden of disease. For this reason, anxiolytics are the most prescribed psychoactive drugs, particularly in the Western world.

AREAS COVERED

This review aims to analyze pharmacokinetic profile, plasma level variations so as the metabolism, interactions and possible relation to clinical effect of several drugs which are used primarily as anxiolytics. The drugs analyzed include benzodiazepines, anticonvulsants (pregabalin, gabapentin), buspirone, β-blockers and antihistamines (hydroxyzine). Regarding the most frequently used anxiolytic benzodiazepines, data on alprazolam, bromazepam, chlordesmethyldiazepam, chlordiazepoxide, clotiazepam, diazepam, etizolam, lorazepam, oxazepam, prazepam and clonazepam have been detailed.

EXPERT OPINION

There is a need for a more balanced assessment of the benefits and risks associated with benzodiazepine use, particularly considering pharmacokinetic profile of the drugs to ensure that patients, who would truly benefit from these agents, are not denied appropriate treatment. An optimal pharmacological approach involving an integrative pharmacokinetic and pharmacodynamic optimization strategy would ensure better treatment and personalization of anxiety disorders. So it would be desirable for the development of new anxiolytic drug(s) that are more selective, fast acting and free from the unwanted effects associated with the traditional benzodiazepines as tolerance or dependence.

Reactivity of commercial benzodiazepine immunoassays to phenazepam

Phenazepam is a long acting benzodiazepine that is not controlled in Canada, the United States or many European countries. The abuse of phenazepam has gained recent attention due to the number of hospitalizations and fatalities resulting from overdose. The compound is relatively potent with recommended doses of 0.5-1.0 mg, or 1/10th the recommended dose of diazepam, and is easy to obtain locally or from international suppliers via the internet. Increased risk of phenazepam overdose is attributed to its potency and the forms in which it is supplied. Individuals without scales or balances are prone to estimate dose amounts of powder visually, which can result in significant errors. The detection of phenazepam has been described using various methods including GC, GC/MS and LC/MS, but no data regarding the sensitivity of commercially available immunoassays exist. In this study, phenazepam-spiked urine samples were analyzed using five commercial instruments and two point of care devices. The concentrations of phenazepam required for detection ranged from 140-462 ng/mL, which is comparable to those of other benzodiazepines. Laboratorians and clinicians should be confident that phenazepam will be detected via most commercial drugs of abuse screens in patients after significant ingestion.

Phenazepam abuse in Finland: findings from apprehended drivers, post-mortem cases and police confiscations

Phenazepam is a long-acting benzodiazepine that, unlike other benzodiazepines, is currently not scheduled as a narcotic in Finland, most other European countries or the USA. It is used as an anxiolytic, sedative-hypnotic and anti-epileptic, mainly in Russia. In Finland, as well as in some other countries, an increase in the unauthorized use of phenazepam has been observed in recent years. In the one year period between July 1, 2010 and June 30, 2011 the prevalence of phenazepam in Finland was assessed among drivers apprehended for driving under the influence of drugs (DUID), in medico-legal autopsy cases and in police confiscations of illicit drugs. In DUID cases an LC-MS/MS method preceded by solid phase extraction was used for the determination of phenazepam. In the post-mortem investigations the sample preparation consisted of liquid-liquid extraction followed by derivatization and the determination was carried out by GC-MS. The police confiscations were analysed by GC-MS. There were 141 positive phenazepam cases among apprehended drivers, representing approximately 3.5% of all confirmed drug cases (n=4007) in this time period. The median (range) phenazepam blood concentration in DUID cases was 0.061 mg/L (0.004-3.600 mg/L). The median phenazepam concentration in cases with no concomitant stimulant use was significantly higher than the overall median concentration. Phenazepam was found in 17 medico-legal autopsy cases and the median (range) blood concentration was 0.048 mg/L (0.007-1.600 mg/L). Phenazepam was not considered by the medico-legal team to be the sole cause of death in any of the cases, the majority of them being accidental opiod overdoses. There were 26 seizures of phenazepam by the Police in the time period studied, some of the batches consisted of a mixture of phenazepam and stimulant designer drugs. The data show that phenazepam abuse is a widespread phenomenon in Finland. A typical user was a male multi-drug user in his 30s. The concentration range of phenazepam among apprehended drivers and medico-legal autopsy cases was wide and the drug was usually found along with other psychoactive drugs. Therefore, although it seems likely that phenazepam contributed to impairment of driving in some DUID cases, the extent of its effect remains unclear and further studies are needed to define the concentrations causing impairment and toxicity.

Toxicologists in public health--Following the path of Louis Roche (based on the Louis Roche lecture "An accidental toxicologist in public health", Bordeaux, 2010)

BACKGROUND

The global burden of clinical toxicology suggests a natural partnership with public health. This article reflects the content of a Louis Roche lecture given in 2010. HISTORICAL CONTEXT: Our practice and research in clinical toxicology has evolved from clinical cases to toxico-epidemiology to public health. This evolution in practice was initially unplanned but gained momentum and impact as we placed it more formally in a public health framework. This perspective is implicit in Louis Roche's call to "examine all aspects of the poisoning problem" and still provides a valuable starting point for any clinical toxicologist.

DISCUSSION

Clinical toxicology has always had a patient centered focus but its greatest successes have been related to public health interventions. Our early failures and later success in pubic health toxicology correlated with our understanding of the importance of partnerships outside our field. The most rapid dissemination and implementation of information derived from research occur through apriori partnerships with other agencies and international partners.

CONCLUSION

Addressing both local and global need has a number of bilateral synergies. Repositioning clinical toxicology into a public health framework increases access to strategic partnerships, research funds, and policy implementation while still addressing questions that are important to clinical practice.

Toxin-related seizures

Toxin-related seizures result from an imbalance in the brain's equilibrium of excitation-inhibition. Fortunately, most toxin-related seizures respond to standard therapy using benzodiazepines. However, a few alterations in the standard approach are recommended to ensure optimal care and expedient termination of seizure activity. If 2 doses of a benzodiazepine do not terminate the seizure activity, a therapeutic dose of pyridoxine (5 g intravenously in an adult and 70 mg/kg intravenously in a child) should be considered. Phenytoin should be avoided because it is ineffective for many toxin-induced seizures and is potentially harmful when used to treat seizures induced by theophylline or cyclic antidepressants.

A case of torsades de pointes induced by severe QT prolongation after an overdose of eperisone and triazolam in a patient receiving nifedipine

INTRODUCTION

Eperisone hydrochloride is a centrally acting muscle relaxant, and triazolam is a short-acting benzodiazepine. Although commonly prescribed, cardiotoxicity induced by a single overdose of either drug is comparatively rare. A patient receiving nifedipine developed torsades de pointes (TdP) because of prolongation of the corrected QT (QTc) interval after an overdose of eperisone hydrochloride and triazolam.

CASE REPORT

A 60-year-old man receiving nifedipine was admitted in a comatose condition 3 h after ingesting 5,000 mg of eperisone and 2.5 mg of triazolam. Electrocardiogram showed sinus rhythm with prolongation of the QTc interval (820 ms). The serum electrolyte levels were as follows: potassium, 3.8 mEq/L; magnesium, 2.4 mg/dL. The serum drug concentrations were high: eperisone, 15,360 ng/mL; triazolam, 110.8 ng/mL. A temporary cardiac pacemaker was implanted immediately after the development of TdP, 11 h after the ingestion. The serum triazolam concentration normalized on day 2. The QTc interval and eperisone concentration normalized on day 6.

CONCLUSION

Eperisone and triazolam overdose can cause life-threatening cardiotoxicity. Electrocardiographic monitoring and serial determination of QTc interval are likely the best way to observe these patients and evaluate the risk of cardiotoxicity.

[Prescription of benzodiazepines by general practitioners in the private sector of Dakar: survey on knowledge and attitudes]

OBJECTIVE

The objective of this study was to evaluate knowledge and attitudes of general practitioners of the private sector, in Dakar, concerning prescription of benzodiazepines, in order to make, possibly, recommendations for their rational use.

METHOD

A survey was done in 2005 with a representative sample of 55 medical doctors. Medical doctors filled in the questionnaire which focused on the main benzodiazepines' indications, those prescribed and their rules of prescription.

RESULTS

The main indications were anxiety, convulsions, epilepsy and insomnia and the benzodiazepines prescribed in first intention were prazepam against anxiety and insomnia and diazepam against convulsions and epilepsy. Practically 17% of medical doctors ignored the existence of limited period of benzodiazepine use and 70.9% of medical doctors considered their training on benzodiazepines insufficient.

CONCLUSION

These results show the necessity to base continuous training for these general practitioners on the pharmacology of benzodiazepines.

Alprazolam induced conformational change in hemoglobin

Alprazolam (ALP) is a widely prescribed sedative and antidepressant benzodiazepine group of drugs. The wide uses of this drug lead us to investigate its possible interaction with hemoglobin (Hb). Spectrophotometric and spectofluorimetric studies showed strong binding of ALP with Hb. Circular dichroic spectra showed that alpha-helical structure of Hb-subunits has been largely changed. On ALP treatment partial pressure of O(2) is increased in the blood indicating release of O(2) from erythrocytes. Further, the binding of ALP-induced conformational changes in Hb resulting in larger Hb particle size was demonstrated by dynamic light scattering experiment. Thus, the present study unambiguously raises question of danger of random usage of ALP, which binds with and changes the function of Hb.

Benzodiazepines prescription in Dakar: a study about prescribing habits and knowledge in general practitioners, neurologists and psychiatrists

Benzodiazepines are relatively well-tolerated medicines but can induce serious problems of addiction and that is why their use is regulated. However, in developing countries like Senegal, these products are used without clear indications on their prescription, their dispensation or their use. This work focuses on the prescription of these medicines with a view to make recommendations for their rational use. Benzodiazepine prescription was studied with psychiatrists or neurologists and generalists in 2003. Specialist doctors work in two Dakar university hospitals and generalists in the 11 health centres in Dakar. We did a survey by direct interview with 29 of 35 specialists and 23 of 25 generalists. All doctors were interviewed in their office. The questionnaire focused on benzodiazepine indications, their pharmacological properties, benzodiazepines prescribed in first intention against a given disease and the level of training in benzodiazepines by doctors. Comparisons between specialists and generalists were made by chi-square test. Benzodiazepines were essentially used for anxiety, insomnia and epilepsy. With these diseases, the most benzodiazepines prescribed are prazepam against anxiety and insomnia and diazepam against epilepsy. About 10% of doctors do not know that there is a limitation for the period of benzodiazepine use. The principal reasons of drugs choice are knowledge of the drugs, habit and low side effects of drugs. All generalists (100%) said that their training on benzodiazepines is poor vs. 62.1% of specialists, and doctors suggest seminars, journals adhesions and conferences to complete their training in this field. There are not many differences between specialists and generalists except the fact that specialists prefer prazepam in first intention in the insomnia treatment where generalists choose bromazepam. In addition, our survey showed that specialists' training in benzodiazepines is better than that of generalists. Overall, benzodiazepine prescription poses problems particularly in training, and national authorities must take urgent measures for rational use of these drugs.

Pharmacotherapy of anxiety

The pharmacological treatment of anxiety has a long and chequered history, and recent years have seen a rich development in the options available to prescribers. Most of the currently used anxiolytic agents act via monoaminergic (chiefly serotonin) or amino acid (GABA or glutamate) neurotransmitters, and this chapter describes the pharmacology of the major drug groups. Clinical applications are discussed with respect to the five major anxiety disorders, as well as simple phobia and depression with concomitant anxiety. Prospective future developments in the field are considered.

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.

High concentrations of diazepam and nordiazepam in blood of impaired drivers: association with age, gender and spectrum of other drugs present

A zero-concentration limit for controlled scheduled drugs in the blood of motorists was introduced in Sweden in 1999 and the annual number of arrests for driving under the influence of drugs (DUID) has since increased eight-fold. However, for prescription drugs that might cause impairment (e.g. benzodiazepines) additional proof is needed to justify prosecution, such as whether the medication was being misused. Over a 2-year period, we found 94 cases of DUID in which the concentrations of diazepam in blood was 1.1 microg/g or more. Diazepam (D) and nordiazepam (ND) were determined in whole blood by capillary gas chromatography with a limit of quantitation of 0.05 microg/g for each compound. The mean (median) and maximum concentrations of D were 2.0 microg/g (1.7 microg/g) and 7.8 microg/g and the corresponding ND concentrations were 1.5 microg/g (1.0 microg/g) and 7.6 microg/g, respectively. The concentration of D in blood exceeded 2 microg/g in 21% of cases and was over 3.0 microg/g in 11% of cases. D and ND were the only drugs present in eight cases (seven men and one women) and in another five cases ethanol was present at concentrations ranging from 0.81 to 1.98 mg/g. Polydrug use was very common in these DUID suspects and D and ND coexisted with amphetamine in 20% of cases, tetrahydrocannabinol in 18% of cases and with both these illicit drugs in 12% of cases. The next most prevalent drug combination was D, ND and morphine (mostly derived from heroin), seen in 13% of cases. Other psychoactive prescription drugs were identified in blood including alprazolam, flunitrazepam, oxazepam, zolpidem and zopiclone. This case series of DUID suspects demonstrate the high frequency of polydrug use showing preference for illicit drugs like amphetamine, cannabis and heroin, in that order. Furthermore, Swedish traffic delinquents frequently overdose with prescription drugs as exemplified here by unusually high concentrations of D and its active metabolite ND.

Australian and New Zealand clinical practice guidelines for the management of adult deliberate self-harm

BACKGROUND

The Royal Australian and New Zealand College of Psychiatrists is co-ordinating the development of clinical practice guidelines (CPGs) in psychiatry, funded under the National Mental Health Strategy (Australia) and the New Zealand Health Funding Authority.

METHOD

For these guidelines, the CPG Team for Deliberate Self-harm reviewed the treatment outcome literature (including meta-analyses) and consulted with practitioners and patients.

TREATMENT RECOMMENDATIONS

(i) Organization of general hospital services to provide: emergency department admission; a safe environment; integrated medical and psychiatric management; risk assessment; identification of psychiatric morbidity, and adequate follow-up. (ii) Detection and treatment of any psychiatric disorder. (iii) Dialectical behaviour therapy, psychoanalytically orientated partial hospitalization or home-based interpersonal therapy (for certain patients) to reduce repetition of deliberate self-harm (DSH).

CONCLUSION

Deliberate self-harm is common and is costly in terms of both individual distress and service provision. General hospitals are often the first point of clinical contact, but may not be appropriately organized to care for these patients. Evidence for the effectiveness of psychological treatments is based on single RCTs without replication. The three recommended psychological treatments are not widely available in Australia and New Zealand, and the interventions that are, such as cognitive behaviour therapy, problem solving and 'green cards' (an agreement guaranteeing access to services), do not reduce repetition of DSH. The effect of follow-up in psychiatric hospitals or in the community is poorly understood. We need to develop and evaluate interventions that will reduce repetition of both fatal and non-fatal deliberate self-harm and improve the person's functioning and quality of life.

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.

Comparison of acute lethal toxicity of commonly abused psychoactive substances

AIMS

To determine the acute lethal toxicity of a range of psychoactive substances in terms of the dose customarily used as a single substance for non-medical purposes.

DESIGN AND METHOD

A structured English-language literature search was conducted to identify experimental studies and clinical reports that documented human and non-human lethal doses of 20 abused substances that are distributed widely in Europe and North America. Four inclusion criteria were specified for the reports, and approximately 3000 relevant records were retrieved from search engines at Biosis, Science Citation Index, Google and the National Library of Medicine's Gateway. In order to account for different drug potencies, a 'safety ratio' was computed for each substance by comparing its reported acute lethal dose with the dose most commonly used for non-medical purposes.

FINDINGS

The majority of published reports of acute lethal toxicity indicate that the decedent used a co-intoxicant (most often alcohol). The calculated safety ratios varied between substances by more than a factor of 100. Intravenous heroin appeared to have the greatest direct physiological toxicity; several hallucinogens appeared to have the least direct physiological toxicity.

CONCLUSIONS

Despite residual uncertainties, the substantial difference in safety ratios suggests that abused substances can be rank-ordered on the basis of their potential acute lethality.

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.

Feasibility of prehospital treatment with activated charcoal: Who could we treat, who should we treat?

OBJECTIVES

To investigate the feasibility and potential risk benefit of prehospital administration of activated charcoal.

METHODS

Review of deliberate self poisoning presentations to the emergency department (ED) of a toxicology unit by ambulance over six years. Data were extracted from a standardised prospective database of poisonings. Outcomes included: number of patients attended by ambulance and number arriving in emergency within one hour. Cases were stratified by ingestion type, based on toxicity and sedative activity.

RESULTS

2041 poisoning admissions were included. The median time to ambulance attendance was 1 h 23 min (IQR 37 min-3 h) and to hospital attendance was 2 h 15 min (IQR 1 h 25 min-4 h). In 774 cases (38%) ambulance attendance occurred within one hour, but in only 161 (8%) did ED attendance occur within one hour. Non-sedating, highly toxic substances were ingested in 55 cases, 24 (23 with GCS>14) with ambulance attendance, and five with ED attendance, within one hour. Conversely 439 patients ingested a less toxic, sedative agent, 160 with ambulance attendance, and 32 with ED attendance, within one hour. Limiting decontamination to patients ingesting highly toxic, non-sedating compounds (GCS<14) reduces the proportion requiring treatment to 23 of the 774 (3.0%), an additional 18 patients.

CONCLUSION

More patients could potentially be decontaminated if all patients attended by ambulance within one hour received charcoal. However, this would expose 128 patients with sedative, low risk poisonings to the risk of aspiration, and only treat 18 extra high risk poisonings. This small potential benefit of prehospital charcoal is unlikely to justify the expense in training and protocols required to implement it

Data collection in clinical toxicology: are there too many variables?

The evidence base of clinical toxicology suffers in comparison to other clinical disciplines. There is an excess of case reports and case series with little in the way of case control or cohort studies, and very few randomized controlled trials. While randomized controlled trials are rightly regarded as the gold standard for interventional studies, they have limitations that are particularly evident in the practice of clinical toxicology. Properly conducted observational studies using quantitative, epidemiological methods [nonrandomized trials, cohort studies (prospective and retrospective), case control methods] can provide answers that may be impossible to obtain from randomized controlled trials. Development of a strong evidence base is essential for progress in clinical toxicology. Whether that evidence base is derived from randomized controlled trials or observational studies, it is essential to collect data. Important observations can be made from basic clinical data and systematic collection of those data into some form of electronic database has siginificant advantages. A clinical database provides accurate information in the areas of clinical practice, quality assurance (audit), and research. In the area of research, an appropriately designed database can be both a source of hypotheses as well as a vehicle to test them. It can also serve as a repository of research data in subsequent randomized controlled trials.

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.

Risk of suicide attempts after benzodiazepine and/or antidepressant use

PURPOSE

Recent publications imply the existence of associations between psychotropic drugs use and risk of suicide. Some studies have measured the tissue level of these drugs in suicide deaths, while others compared toxicity indices, defined as number of suicide deaths per million prescriptions for individual antidepressants. Few of these studies used unexposed controls. The objective of this cohort study was to evaluate suicide attempts in subjects recently exposed to benzodiazepines and/or antidepressants, as compared to unexposed controls.

METHODS

A population of 225,796 persons with prescriptions for benzodiazepines were selected from the Saskatchewan Health Data Bases. Controls consisted of 97,862 individuals who did not receive benzodiazepines.

RESULTS

Stratifying the populations into antidepressant users and non-antidepressant users indicated that nonantidepressant users had statistically significant associations between suicide attempts and benzodiazepine use (odds ratio (OR) = 6.2), antipsychotic use, (OR = 2.6), and a history of past treatment for drug/alcohol abuse (OR = 13.4). Antidepressant users showed a statistically significant relation only with past treatment for drug/alcohol use (OR = 5.8). It is argued that the large OR for antidepressant use is due to confounding by indication. If so, the concept of toxicity index is misleading and should not be used.

CONCLUSIONS

The association between benzodiazepine use and attempted suicide is especially high for nonantidepressant users, for the young, and for males. Whether this relationship is causal or not, physicians should be aware of the high potential for suicide attempts when prescribing benzodiazepines for patients in these high risk groups.

Health care. A model for the management of self-poisoning

OBJECTIVE

To describe the development and activity of a multidisciplinary service to manage self-poisoning.

DESIGN

Descriptive, comparative study with prospective data collection.

SETTING

Regional toxicology treatment centre in the Hunter area of New South Wales (NSW) with primary and secondary referral service to 385,000 people and tertiary referral service to a further 100,000.

PATIENTS

All patients (1987-1995) with poisoning or envenomation presenting to the Hunter Area Toxicology Service (HATS).

MAIN OUTCOME MEASURES

Average length of stay for HATS compared with national and NSW hospitals; mortality data for HATS compared with NSW.

RESULTS

Average length of stay for HATS was 0.53-1.22 days shorter than for all Australian hospitals, potentially saving 518 bed-days, valued at $468,000 per year. Average length of stay was 0.94-3.39 days shorter than for all NSW hospitals, saving 1470 bed-days at $1.4 million per year. Inpatient mortality (0.2%; 95% confidence interval, 0.0-1.1) was not significantly different from NSW (0.5%; 95% CI, 0.2-0.8). Standardised mortality ratios showed no greater all-cause suicide mortality.

CONCLUSIONS

In our centralised model for managing self-poisoning, all toxicology patients in an area health service are diverted to one hospital, where all patients with deliberate self-poisoning are admitted under the one multidisciplinary team, and all receive psychiatric assessment. This model has substantially reduced bed stay, with considerable savings to the Hunter Area Health Service manifested as an increase in beds available for other purposes.

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.

Optimal management of anxiety in older patients

Although the incidence of anxiety disorders diminishes with age, the prevalence of anxiety symptoms among older patients is substantial. These symptoms, which include cognitive and somatic manifestations, are a source of diminished quality of life. The many potential sources of illness- and medication-induced anxiety must be excluded before instituting treatment. The general principles of antianxiety medication treatment in older patients include: (i) symptom relief with minimum sedation; (ii) improvement in sleep; (iii) freedom from autonomic and cognitive toxicities; and (iv) freedom from physical dependence and drug interactions. Older compounds such as the tricyclic antidepressants should be avoided, since more modern agents (e.g. benzodiazepines and buspirone) are well tolerated and effective. Modern antidepressants have also been used to reduce anxiety symptoms, although there is a potential for the opposite effect to occur. The selective serotonin reuptake inhibitors appear to be better suited to treating syndromes such as panic and obsessive-compulsive disorder, whereas nefazodone would be a better choice for generalised anxiety complicated by depression.