Association of road-traffic accidents with benzodiazepine use

Utilização de benzodiazepínicos no Serviço Municipal de Saúde de Coronel Fabriciano, Minas Gerais

Neste estudo foram avaliadas as indicações de benzodiazepínicos no Serviço Municipal de Saúde de Coronel FabricianoMG, verificando sua conformidade com o preconizado pela literatura. O estudo avaliou todas as receitas desses medicamentos provenientes das Unidades Municipais de Saúde no período de Setembro a Outubro de 2006, os formulários de indicação clínica preenchidos pelo prescritor e cadastros informatizados do serviço. Analisaram-se 1.866 receitas, sendo 59,7% do Diazepam e o restante do Clonazepam. A Dose Diária Definida por mil habitantes por dia foi de 24,69 para o Diazepam e de 3,58 para o Clonazepam. Cerca de 50% das indicações relatadas pelos médicos foram como hipnótico ou ansiolítico, 21,9% para "uso crônico/dependência" e o restante para outras indicações. Das receitas que atenderam aos critérios de inclusão para análise da adequação da indicação (1618), cerca de 70% foram consideradas não adequadas, tendo em vista a indicação e o tempo de tratamento. Houve um alto percentual de inadequação na utilização de benzodiazepínicos, principalmente pelo uso prolongado e para atender a casos considerados pelos prescritores como uso crônico/dependência. Assim, há responsabilidade do serviço de saúde na manutenção da dependência.

Within-person study designs had lower precision and greater susceptibility to bias because of trends in exposure than cohort and nested case-control designs

OBJECTIVE

To compare precision and apparent bias between cohort, nested case-control, self-controlled case series, case-crossover, and case-time-control study designs.

STUDY DESIGN AND SETTING

Study designs were implemented to evaluate the association between thiazolidinediones (TZDs) and heart failure, TZDs and fracture, and liver enzyme-inducing anticonvulsants and fracture.

RESULTS

Effect estimates were similar for the cohort and case-control study; for the association between TZDs and fracture in women, the hazard ratio was 1.36 (1.18, 1.56) and odds ratio (OR) was 1.44 (1.21, 1.70). For this clinical example, the self-controlled case series gave upward bias when follow-up was censored at the outcome (incidence rate ratio [IRR], 7.08; 4.96, 10.09) but was otherwise unbiased (IRR, 1.41; 1.14, 1.75). The retrospective case-crossover OR was 3.24 (2.18, 4.80), which was reduced by either bidirectional sampling (OR, 1.20; 0.98, 1.46) or with the case-time-control design (OR, 1.40; 1.09, 1.81). Findings on apparent bias were similar for the other two clinical examples. In each clinical example, within-person designs had considerably lower precision than the cohort or case-control study designs.

CONCLUSION

When long-term exposures are analyzed, within-person study designs may have lower precision and greater susceptibility to bias. Bias may be reduced by sampling follow-up both before and after the outcome or with the case-time-control study design.

At-fault motor vehicle crash risk in elderly patients treated with antidepressants

OBJECTIVE

To assess whether antidepressant treatment is associated with a temporary increase in the risk of a motor vehicle crash among older adults.

DESIGN

Population-based case-only time-to-event analysis.

SETTING AND SUBJECTS

Data from transportation and healthcare databases for adults age 65 and older in Ontario, Canada, between January 1, 2000, and October 31, 2007. Consecutive adults who had a motor vehicle crash anytime following their 66th birthday.

MEASUREMENTS

The primary exposure variable was treatment with antidepressant medication, and the primary outcome measure was a motor vehicle crash.

RESULTS

A total of 159,678 individuals had a crash during the study, of whom 7,393 (5%) received an antidepressant in the month prior to the crash. The hazard ratio (HR) of crash associated with second-generation antidepressants was 1.10 (95% confidence interval [CI]: 1.07-1.13, χ² = 41.77, df = 1, p <0.0001), adjusted for gender, license suspensions, and other medications, but the risk for first-generation antidepressants was not significant. The increased risk was restricted to those who were also concurrently prescribed a benzodiazepine (adjusted HR: 1.23, 95% CI: 1.17-1.28, χ² = 85.28, df = 1, p <0.0001) or a strong anticholinergic medication (adjusted HR: 1.63, 95% CI: 1.57-1.69, χ² = 627.31, df = 1, p <0.0001), and was confined to crashes where the patient was at fault. The increased risk was apparent for the first 3-4 months following initiation of an antidepressant and returned to baseline thereafter.

CONCLUSIONS

Prescriptions for second-generation antidepressants in older adults are associated with a modest increased risk of motor vehicle crashes, when combined with other medications that can impair cognition.

Benzodiazepines revisited--will we ever learn?

AIMS

To re-examine various aspects of the benzodiazepines (BZDs), widely prescribed for 50 years, mainly to treat anxiety and insomnia. It is a descriptive review based on the Okey Lecture delivered at the Institute of Psychiatry, King's College London, in November 2010.

METHODS

A search of the literature was carried out in the Medline, Embase and Cochrane Collaboration databases, using the codeword 'benzodiazepine(s)', alone and in conjunction with various terms such as 'dependence', 'abuse', etc. Further hand-searches were made based on the reference lists of key papers. As 60,000 references were found, this review is not exhaustive. It concentrates on the adverse effects, dependence and abuse.

RESULTS

Almost from their introduction the BZDs have been controversial, with polarized opinions, advocates pointing out their efficacy, tolerability and patient acceptability, opponents deprecating their adverse effects, dependence and abuse liability. More recently, the advent of alternative and usually safer medications has opened up the debate. The review noted a series of adverse effects that continued to cause concern, such as cognitive and psychomotor impairment. In addition, dependence and abuse remain as serious problems. Despite warnings and guidelines, usage of these drugs remains at a high level. The limitations in their use both as choice of therapy and with respect to conservative dosage and duration of use are highlighted. The distinction between low-dose 'iatrogenic' dependence and high-dose abuse/misuse is emphasized.

CONCLUSIONS

The practical problems with the benzodiazepines have persisted for 50 years, but have been ignored by many practitioners and almost all official bodies. The risk-benefit ratio of the benzodiazepines remains positive in most patients in the short term (2-4 weeks) but is unestablished beyond that time, due mainly to the difficulty in preventing short-term use from extending indefinitely with the risk of dependence. Other research issues include the possibility of long-term brain changes and evaluating the role of the benzodiazepine antagonist, flumazenil, in aiding withdrawal.

Psychotropic medications and crash risk in older drivers: a review of the literature

OBJECTIVE

. An extensive review of Australian and international literature was undertaken, examining the association between psychotropic medications and crash risk involving older drivers.

METHODS

. The review summarizes the findings in experimental and epidemiological studies related to (a) prevalence of psychotropic medication use among older drivers; (b) side effects of driving under the influence of psychotropic medications; and (c) association between psychotropic medications and crash risk for older drivers.

RESULTS

. Current evidence indicates that several types of psychotropic medications have the potential to impair driving ability and increase the risk of crash involvement. A major limitation is that few studies have specifically examined the effects on older drivers, despite the fact that the majority of the population using psychotropic medications are older. Discussion. More knowledge about the safety of therapeutic use of psychotropic medications is needed. Large-scale, whole-population, epidemiological studies, such as data linkage studies, may be the optimal study design.

Road traffic accidents and psychotropic medication use in The Netherlands: a case-control study

AIM

To examine the association between the use of commonly prescribed psychotropic medications and road traffic accident risk.

METHODS

A record-linkage database was used to perform a case-control study in The Netherlands. The data came from three sources: pharmacy prescription data, police traffic accident data and driving licence data. Cases were defined as drivers, who had a traffic accident that required medical assistance between 2000 and 2007. Controls were defined as adults, who had a driving licence and had no traffic accident during the study period. Four controls were matched for each case. The following psychotropic medicine groups were examined: antipsychotics, anxiolytics, hypnotics and sedatives, and antidepressants stratified in the two groups, SSRIs and other antidepressants. Various variables, such as age, gender, medicine half-life and alcohol use, were considered for the analysis.

RESULTS

Three thousand nine hundred and sixty-three cases and 18,828 controls were included in the case-control analysis. A significant association was found between traffic accident risk and exposure to anxiolytics (OR = 1.54, 95% CI 1.11, 2.15), and SSRIs (OR = 2.03, 95% CI 1.31, 3.14). A statistically significant increased risk was also seen in chronic anxiolytic users, females and young users (18 to 29 years old), chronic SSRI users, females and middle-aged users (30 to 59 years old), and intermediate half-life hypnotic users.

CONCLUSIONS

The results of this study support previous findings and confirm that psychoactive medications can constitute a problem in traffic safety. Both health care providers and patients should be properly informed of the potential risks associated with the use of these medicines.

Next-day effects of ramelteon (8 mg), zopiclone (7.5 mg), and placebo on highway driving performance, memory functioning, psychomotor performance, and mood in healthy adult subjects

STUDY OBJECTIVES

To evaluate the next-morning residual effects of ramelteon (8 mg), zopiclone (7.5 mg), and placebo on driving performance, memory functioning, psychomotor performance, and mood in healthy adult subjects following bedtime dosing and a middle of the night awakening.

DESIGN

Single-center, randomized, double-blind, double-dummy, placebo-controlled, crossover study.

SETTING

Utrecht University, The Netherlands.

PARTICIPANTS

30 healthy volunteers (15 males and 15 females).

INTERVENTIONS

a single dose of ramelteon (8 mg), zopiclone (7.5 mg), and placebo, administered at bedtime.

MEASUREMENTS

A balance test was performed at night. Other tests were performed the following morning, 8.5 h after administration. Subjects performed a 100-km highway driving test in normal traffic. Primary outcome measure was the standard deviation of the lateral position (SDLP), i.e., the weaving of the car. After driving, cognitive, memory, and psychomotor tests were performed and mood was assessed.

RESULTS

SDLP was significantly increased after the intake of ramelteon (+2.2 cm) and zopiclone (+2.9 cm). Ramelteon and zopiclone produced significant impairment on reaction time (P<0.024) in the Sternberg Memory Scanning Test, slow (P<0.007) and fast (P<0.010) tracking, reaction speed (P<0.015) and tracking (P<0.001) in the Divided Attention Test, and delayed recall (P<0.032) in the Word Learning Test. In contrast to ramelteon, zopiclone additionally impaired performance on the Digit Symbol Substitution Test (P<0.001) and the balance test (P<0.001).

CONCLUSIONS

Ramelteon (8 mg) and zopiclone (7.5 mg) significantly impaired driving performance, cognitive, memory, and psychomotor performance the morning following bedtime administration. In contrast to zopiclone, ramelteon produced no balance impairments. CLINICAL TRIAL IDENTIFIER: NCT00319215 (www.clinicaltrials.gov).

Psychoactive medications and crash involvement requiring hospitalization for older drivers: a population-based study

OBJECTIVES

To determine the association between psychoactive medications and crash risk in drivers aged 60 and older.

DESIGN

Retrospective population-based case-crossover study.

SETTING

A database study that linked the Western Australian Hospital Morbidity Data System and the Pharmaceutical Benefits Scheme.

PARTICIPANTS

Six hundred sixteen individuals aged 60 and older who were hospitalized as the result of a motor vehicle crash between 2002 and 2008 in Western Australia.

MEASUREMENTS

Hospitalization after a motor vehicle crash.

RESULTS

Greater risk for a hospitalization crash was found for older drivers prescribed benzodiazepines (odds ratio (OR)=5.3, 95% confidence interval (CI)=3.6-7.8, P<.001), antidepressants (OR=1.8, 95% CI=1.0-3.3, P=.04), and opioid analgesics (OR=1.5, 95% CI=1.0-2.3, P=.05). Crash risk was significantly greater in men prescribed a benzodiazepine (OR=6.2, 95% CI=3.2-12.2, P<.001) or an antidepressant (OR=2.7, 95% CI=1.1-6.9, P=.03). Women prescribed benzodiazepines (OR=4.9, 95% CI=3.1-7.8, P<.001) or opioid analgesics (OR=1.8, 95% CI=1.1-3.0, P=.03) also had a significantly greater crash risk. Subgroup analyses further suggested that drivers with (OR=4.0, 95% CI=2.9-8.1, P<.001) and without (OR=6.0, 95% CI=3.8-9.5, P<.001) a chronic condition who were prescribed benzodiazepines were at greater crash risk. Drivers with a chronic condition taking antidepressants (OR=3.4, 95% CI=1.3-8.5, P=.01) also had a greater crash risk.

CONCLUSION

Psychoactive medication usage was associated with greater risk of a motor vehicle crash requiring hospitalization in older drivers.

Psychoactive substance use and the risk of motor vehicle crash injuries in southern Taiwan

The purpose of this study was to examine the association between psychoactive drug use and motor vehicle crash (MVC) injuries requiring hospitalization in southern Taiwan. A case-control study was conducted in southern Taiwan from January 2009 to December 2009. The cases included car or van drivers who were involved in MVCs and required hospitalization. Demographic and trauma-related data were collected from questionnaires and hospital and ambulance records. Urine and/or blood samples were collected on admission. The controls consisted of drivers who were randomly recruited while driving on public roads. Study subjects were interviewed and asked to provide urine samples. All blood and urine samples were tested for alcohol and a number of other legal and illegal drugs. Only those subjects who provided urine and/or blood specimens were included in the study. During the study period, 254 case patients and 254 control drivers were enrolled. The analysis showed an odds ratio (OR) of 3.41 (95% confidence intervals (95% CI), 1.76-6.70; p < 0.001) for persons taking benzodiazepines, and an OR of 3.50 (95% CI, 1.81-6.85; p < 0.001) for those taking alcohol (blood alcohol concentrations (BAC) ≥ 0.8 g/l) with regard to hospitalizations due to MVCs. For persons taking combinations of benzodiazepines and alcohol, the OR increased to 5.12 (95% CI: 1.77-15.91, p < 0.001). This study concluded that drug use among motor vehicle drivers increases the risk of MVCs that require hospitalization. From a public health perspective, the high risk ratios are concerning, and preventive measures are warranted.

Psychomotor performance after intake of zopiclone compared with intake of ethanol: a randomized, controlled, double-blinded trial

The sleep medicine zopiclone (eszopiclone) is commonly used in most Western countries. The focus on legislation for possible traffic-impairing nonalcohol drugs have caused a need for comparing traffic relevant behavior after intake of commonly used psychoactive drugs to blood alcohol concentrations (BACs). We aimed to compare psychomotor effects at 3 levels of behavior at different blood zopiclone concentrations to effects seen at different BACs. We performed a randomized double-blinded trial on 16 healthy volunteers who received either 10 or 5 mg zopiclone, 50 g ethanol or placebo in a crossover design. The volunteers performed computerized tests at baseline, 1, 3.5, and 6.5 hours after intake, accompanied by blood sampling. Impairment was found at all 3 behavior levels. For zopiclone, impairment was most pronounced at behavior level 1 (automotive behavior); a mean blood zopiclone concentration at 39 μg/L achieved 1 hour after intake of 10 mg zopiclone was accompanied by more impairment than BAC 0.074 %. At behavior levels 2 (control behavior) and 3 (executive planning), the psychomotor impairment accompanying approximately 39 μg/L zopiclone seemed comparable to a BAC of approximately 0.074%. No test components were impaired at 6.5 hours after intake.

Antidepressant prescriptions: an acute window for falls in the nursing home

BACKGROUND

Although many studies have implicated antidepressants as a risk factor for falls, it is not clear if risk accrues with duration of use or if there are acute risks associated with initiation of the prescription. We conducted a case-crossover study of nursing home residents with a fall to determine the effect of an antidepressant change (defined as the new prescription of an antidepressant or increasing the dose of a previously used antidepressant) on fall risk.

METHODS

Among 1,181 nursing home fallers, we compared the frequency of antidepressant changes during the hazard period (1-7 days before the fall) with the frequency of antidepressant changes during the control period (8-14 days before the fall). Odds ratios were estimated using conditional logistic regression models. Results were estimated for non-selective serotonin reuptake inhibitors (SSRI) and SSRI prescriptions, separately.

RESULTS

Mean age was 88 years, and 71% were females. Seventy participants experienced an antidepressant change during the hazard and/or control periods. The maximum effect of falling occurred within 2 days of a non-SSRI change (odds ratio: 4.7, 95% confidence interval, 1.3-16.2). The effect on falling was no longer significant at 5 days (odds ratio: 1.9, 95% confidence interval, 0.9-4.0). No association was found between SSRI changes and falls.

CONCLUSIONS

Nursing home residents are at high risk of falls during the days following a new prescription or increased dose of a non-SSRI antidepressant. Increased surveillance should occur, particularly during the first 48 hours, in an effort to decrease falls.

Income and the midlife peak in common mental disorder prevalence

BACKGROUND

The prevalence of psychological distress and common mental disorders has been shown to peak in midlife but analyses have ignored the association of poor material circumstances with prevalence. This study aimed to test the hypothesis that the midlife prevalence peak occurs only in lower-income households.

METHOD

Pooled data were used from the annual Health Survey for England, a nationally representative cross-sectional study, on community-dwelling individuals aged ≥ 16 years from years 1997 to 2006 (n=100 457). 12-item General Health Questionnaire scores, reported mental illness diagnoses and receipt of relevant medication were assessed in relation to household income and age. Analyses were separated by gender and adjusted for age, ethnicity, smoking, social class, education and co-morbidities.

RESULTS

Prevalence of psychological distress, diagnoses and treatments rose with age until early middle age and declined subsequently. In analyses conducted separately by income categories, this pattern was marked in low-income groups but absent in high-income groups. Income-related inequalities in the prevalence of psychological distress were greatest in midlife; for example, in men aged 45-54 years the odds ratio of receiving psychiatric medication in the lowest income group compared with the highest was 7.50 [95% confidence interval (CI) 4.24-13.27] and in women aged 45-54 years the odds ratio of reporting mental illness was 10.25 (95% CI 6.16-17.05).

CONCLUSIONS

An increased prevalence of psychological distress, common mental disorder diagnoses and treatment in midlife is not a universal phenomenon but is found only in those in low-income households. This implies the phenomenon is not inevitable but is potentially manageable or preventable.

Sedative medication use: prevalence, risk factors, and associations with body mass index using population-level data

STUDY OBJECTIVES

To estimate the prevalence of and identify sociodemographic risk factors for sedative medication use in the general Canadian population, and to examine the association between sedative medication use and body mass index (BMI).

DESIGN

Cross-sectional study

SETTING

Canadian population

PARTICIPANTS

Participants from the 1994-2003 Canadian national health surveys, the National Population Health Survey (NPHS) and the Canadian Community Health Survey (CCHS). For the 2003 CCHS, n = 134,072, ages 12-80+ years.

INTERVENTIONS

Not applicable

MEASUREMENTS AND RESULTS

The overall prevalence of sedative medication use in Canada in 2003 was 5.5%, having more than doubled since 1994. Notable rises in sedative medication use have occurred among men, non-elderly, and obese individuals. After adjusting for potential sociodemographic and health status confounders, including psychiatric comorbidities, the odds of sedative use were significantly greater among morbidly obese (BMI ≥ 35 kg/m(2)) men (OR = 1.89, 95%CI = 1.02-3.53) and underweight (BMI < 18.5 kg/m(2)) women (OR = 2.11, 95%CI = 1.26-3.53).

CONCLUSIONS

The use of sedative medications has substantially risen among the general Canadian population, and among particular population subgroups. The greater odds of sedative medication use found among morbidly obese men may reflect the presence of underlying obstructive sleep apnea, which may in turn serve to explain in part the known relationship between sedative medications and mortality. The increase in sedative medications coupled with their known adverse health associations raises potential public health concerns.

Potential for bias in case-crossover studies with shared exposures analyzed using SAS

The case-crossover method is an efficient study design for evaluating associations between transient exposures and the onset of acute events. In one common implementation of this design, odds ratios are estimated using conditional logistic or stratified Cox proportional hazards models, with data stratified on each individual event. In environmental epidemiology, where aggregate time-series data are often used, combining strata with identical exposure histories may be computationally convenient. However, when the SAS software package (SAS Institute Inc., Cary, North Carolina) is used for analysis, users can obtain biased results if care is not taken to properly account for multiple cases observed at the same time. The authors show that fitting a stratified Cox model with the "Breslow" option for handling tied failure times (i.e., ties = Breslow) provides unbiased health-effects estimates in case-crossover studies with shared exposures. The authors' simulations showed that using conditional logistic regression-or equivalently a stratified Cox model with the "ties = discrete" option-in this setting leads to health-effect estimates which can be biased away from the null hypothesis of no association by 22%-39%, even for small simulated relative risks. All methods tested by the authors yielded unbiased results under a simulated scenario with a relative risk of 1.0. This potential bias does not arise in R (R Foundation for Statistical Computing, Vienna, Austria) or Stata (Stata Corporation, College Station, Texas).

Zolpidem and zopiclone impair similarly monotonous driving performance after a single nighttime intake in aged subjects

RATIONALE

Although hypnotics are primarily used by older people, the residual effects the morning after a single nighttime intake of the two most commonly prescribed hypnotics, zolpidem (Zp) and zopiclone (Zc), on older middle-aged drivers have not been evaluated and compared.

METHODS

Sixteen healthy subjects, 55 to 65 years of age, participated in this double-blind, balanced, cross-over study. Zc (7.5 mg), Zp (10 mg) and flunitrazepam (Fln) (1 mg) or a placebo was administered at each subject's home at 11.00 pm. The next morning, at 9.00 am, the subjects had to drive in a simulated monotonous driving environment for 1 h. During each morning session, two blood samples were collected, and subjective feelings of alertness were completed three times.

RESULTS

In comparison to placebo, Zp and Zc equivalently and significantly impaired the standard deviation of lateral position, the standard deviation of speed and the number of road exits. Detectable blood concentrations were found with Zp in 11 subjects at 8.30 am and at 1.30 pm. The subjective alertness factor was significantly impaired with Zp.

CONCLUSIONS

This is the first study revealing residual effects of Zp on driving performance in ageing drivers which are similar to that of Zc. Studying the effects of medication in different age ranges appears useful to complete the studies on behavioural-pharmacological effects of medication. To reduce the incidence of driving accidents due to prescription drugs, patients should be warned at the time of treatment initiation that they should avoid driving.

Benzodiazepines: sample preparation and HPLC methods for their determination in biological samples

Benzodiazepines (BDZs) belong to a group of substances known for their sedative, antidepressive, muscle relaxant, tranquilizer, hypnotic and anticonvulsant properties. Their determination in biological fluids is essential in clinical assays as well as in forensics and toxicological studies. Researchers focus on the development of rapid, accurate, precise and sensitive methods for the determination of BDZs and their metabolites. A large number of analytical methods using different techniques have been reported, but none can be considered as the method of choice. BDZs are usually present at trace levels (microgram or nanogram per milliliter) in a complex biological matrix and the potentially interfering compounds must be isolated by various extraction techniques before analysis. An extended and comprehensive review is presented herein, focusing on sample preparation (pretreatment and extraction) and HPLC conditions applied by different authors. These methods enable bioanalysts to achieve detection limits down to 1-2 ng/ml using UV/diode array detection, readily available in most laboratories, and better than 1 ng/ml using electron capture detection, which is lower than that obtained using a nitrogen phosphorus detector. MS interfaced with electrospray ionization offered a similar sensitivity, while negative chemical ionization MS or sonic spray ionization MS provided sensitivity down to 0.1 ng/ml.

Sleep disorders, medical conditions, and road accident risk

Sleep disorders and various common acute and chronic medical conditions directly or indirectly affect the quality and quantity of one's sleep or otherwise cause excessive daytime fatigue. This article reviews the potential contribution of several prevalent medical conditions - allergic rhinitis, asthma, chronic obstructive pulmonary disease, rheumatoid arthritis/osteoarthritis - and chronic fatigue syndrome and clinical sleep disorders - insomnia, obstructive sleep apnea, narcolepsy, periodic limb movement of sleep, and restless legs syndrome - to the risk for drowsy-driving road crashes. It also explores the literature on the cost-benefit of preventive interventions, using obstructive sleep apnea as an example. Although numerous investigations have addressed the impact of sleep and medical disorders on quality of life, few have specifically addressed their potential deleterious effect on driving performance and road incidents. Moreover, since past studies have focused on the survivors of driver crashes, they may be biased. Representative population-based prospective multidisciplinary studies are urgently required to clarify the role of the fatigue associated with common ailments and medications on traffic crash risk of both commercial and non-commercial drivers and to comprehensively assess the cost-effectiveness of intervention strategies.

The additive effects of alcohol and benzodiazepines on driving

OBJECTIVES

To examine the relationship between the combination of alcohol and benzodiazepines and the risk of committing an unsafe driver action.

METHODS

We used data from the Fatality Analysis Reporting System (1993-2006) on drivers aged 20 or older who were tested for both alcohol and drugs. Using a case-control design, we compared drivers who had at least one unsafe driver action (UDA; e.g., weaving) recorded in relation to the crash (cases) to drivers who did not (controls).

RESULTS

Drivers who tested positive for intermediate- and long-acting benzodiazepines in combination with alcohol had significantly greater odds of a UDA compared to those under the influence of alcohol alone, up to blood alcohol concentrations (BACs) of 0.08 and 0.05 g/100 ml, respectively. The odds of a UDA with short-acting benzodiazepines combined with alcohol were no different than for alcohol alone.

CONCLUSIONS

This study demonstrates that the combination of alcohol and benzodiazepines can have detrimental effects on driving beyond those of alcohol alone. By describing these combined effects in terms of BAC equivalencies, this study also allows for the extrapolation of simple, concrete concepts that communicate risk to the average benzodiazepine user.

Effects of the use of hypnotics on cognition

Hypnotic drugs are intended to induce sedation and promote sleep. As a result, they have deteriorating effects on cognitive performance following intake. Most hypnotics are benzodiazepine receptor agonists which can have effects on memory in addition to their sedative effects. Other sedating drugs, such as histamine H1 antagonists or melatonin agonists, may have less effect on memory and learning. Hypnotics with other mechanisms of action are currently being investigated for efficacy and safety. For patients using hypnotic drugs, the effects on cognition are relevant to the extent that a drug dose affects daytime performance. Use of benzodiazepine hypnotics is associated with increased risk of car accidents and falling. Therefore, most hypnotics are studied to determine whether they produce residual sedation and impairing effects on performance the morning after bedtime use. Experimental studies using a standardized driving test clearly show that some drugs and doses produce severe residual effects, whereas others seem to have no or only minor impairing effects on next-day performance. No hypnotic has been found yet to improve daytime performance. Studies on long-term use of benzodiazepine hypnotics suggest that effects on daytime performance may diminish over time due to tolerance. However, there are also studies showing that performance may improve after discontinuation of chronic benzodiazepine use, which suggests that tolerance may not be complete.

Pharmacoepidemiology of benzodiazepine and sedative-hypnotic use in a Canadian general population cohort during 12 years of follow-up

OBJECTIVE

benzodiazepines (BDZs) and similar sedative-hypnotics (SSHs) can have both beneficial and adverse effects. Clinical practice guidelines indicate that the course of treatment should usually be brief (a few weeks), but patients often take these medications for longer periods of time. We hypothesized that treatment with antidepressants (ADs) would be associated with a shorter duration of SSHs use as mood and anxiety disorders may underlie the symptoms usually targeted by BDZ treatment.

METHOD

our study used data from a Canadian longitudinal general health study, the National Population Health Survey, which has collected data since 1994. Data are currently available to 2006. At each interview, all medications taken in the preceding 2 days are recorded. In our study, we used proportional hazard models to describe patterns of initiation and discontinuation of these medications in the general population.

RESULTS

at each interview, the frequency of BDZ-SSH use was 2% to 3%. About 1% of the population initiated use in each 2-year follow-up period. Contrary to expectation, taking ADs predicted initiation of BDZ-SSHs, but not discontinuation.

CONCLUSIONS

unexpectedly, respondents taking ADs had a higher frequency of new BDZ-SSH use. AD use may be a marker for depression severity or comorbidity, such that the observed results may be an artifact of confounding by these factors. Irrespective of etiology, initiation of AD treatment does not appear to negate the risk of long-term BDZ-SSH use.

Prescription medicines and the risk of road traffic crashes: a French registry-based study

BACKGROUND

In recent decades, increased attention has been focused on the impact of disabilities and medicinal drug use on road safety. The aim of our study was to investigate the association between prescription medicines and the risk of road traffic crashes, and estimate the attributable fraction.

METHODS AND FINDINGS

We extracted and matched data from three French nationwide databases: the national health care insurance database, police reports, and the national police database of injurious crashes. Drivers identified by their national health care number involved in an injurious crash in France, between July 2005 and May 2008, were included in the study. Medicines were grouped according to the four risk levels of the French classification system (from 0 [no risk] to 3 [high risk]). We included 72,685 drivers involved in injurious crashes. Users of level 2 (odds ratio [OR]  = 1.31 [1.24-1.40]) and level 3 (OR  = 1.25 [1.12-1.40]) prescription medicines were at higher risk of being responsible for a crash. The association remained after adjustment for the presence of a long-term chronic disease. The fraction of road traffic crashes attributable to levels 2 and 3 medications was 3.3% [2.7%-3.9%]. A within-person case-crossover analysis showed that drivers were more likely to be exposed to level 3 medications on the crash day than on a control day, 30 days earlier (OR  = 1.15 [1.05-1.27]).

CONCLUSION

The use of prescription medicines is associated with a substantial number of road traffic crashes in France. In light of the results, warning messages appear to be relevant for level 2 and 3 medications and questionable for level 1 medications. A follow-up study is needed to evaluate the impact of the warning labeling system on road traffic crash prevention.

British Association for Psychopharmacology consensus statement on evidence-based treatment of insomnia, parasomnias and circadian rhythm disorders

Sleep disorders are common in the general population and even more so in clinical practice, yet are relatively poorly understood by doctors and other health care practitioners. These British Association for Psychopharmacology guidelines are designed to address this problem by providing an accessible up-to-date and evidence-based outline of the major issues, especially those relating to reliable diagnosis and appropriate treatment. A consensus meeting was held in London in May 2009. Those invited to attend included BAP members, representative clinicians with a strong interest in sleep disorders and recognized experts and advocates in the field, including a representative from mainland Europe and the USA. Presenters were asked to provide a review of the literature and identification of the standard of evidence in their area, with an emphasis on meta-analyses, systematic reviews and randomized controlled trials where available, plus updates on current clinical practice. Each presentation was followed by discussion, aimed to reach consensus where the evidence and/or clinical experience was considered adequate or otherwise to flag the area as a direction for future research. A draft of the proceedings was then circulated to all participants for comment. Key subsequent publications were added by the writer and speakers at draft stage. All comments were incorporated as far as possible in the final document, which represents the views of all participants although the authors take final responsibility for the document.

Increased risk of hospitalization related to motor vehicle accidents among people taking zolpidem: a case-crossover study

BACKGROUND

Several epidemiological and experimental studies have found a positive association between the risk of motor vehicle accidents (MVAs) and use of zopiclone and benzodiazepines. There is, however, little evidence of any risk of MVA attributable to the use of zolpidem 1 day before such accidents. We attempted to determine whether the use of zolpidem 1 day before is associated with an increased risk of an MVA.

METHODS

Using a 1-million-person randomly sampled cohort from the Taiwan National Health Insurance reimbursement database, 12 929 subjects were identified as having been hospitalized between 1998 and 2004 due to an MVA. Using a case-crossover design, we selected the day before an MVA as the case period for each subject, and the 91st, 182nd, and 273rd days before the case period as 3 retrospective control periods. Conditional logistical regression models were constructed to calculate the odds ratio (OR) of having an MVA and the exposure of zolpidem 1 day before. We calculated doses of benzodiazepines, zopiclone, and zolpidem based on their defined daily dose.

RESULTS

The adjusted OR for involvement in an MVA after taking 1 defined daily dose of zolpidem was 1.74 (95% confidence interval: 1.25-2.43). There were also positive effects for different washout periods and cumulative doses at 7, 14, 21, and 28 days before the occurrence of an MVA.

CONCLUSIONS

Use of zolpidem 1 day before might be associated with an increased risk of MVA. Thus, precautionary warnings should be provided when prescribing zolpidem.

Sleep disturbances and adverse driving events in a predominantly male cohort of active older drivers

OBJECTIVES

To evaluate the association between sleep disturbances and adverse driving events in active older drivers.

DESIGN

Longitudinal.

SETTING

Clinic and community sites in greater New Haven, Connecticut.

PARTICIPANTS

Four hundred thirty older persons (mean age 78.5, 84.9% male) who drove at least once a week.

MEASUREMENTS

Baseline measures included self-reported driving patterns and sleep questionnaires (Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), and Sleep Apnea Clinical Score (SACS)). The primary outcome was an adverse driving event based on self-report and driving records and categorized as a crash or traffic infraction (composite I) or as a crash, traffic infraction, near crash, or getting lost (composite II).

RESULTS

Participants reported driving a median of 17.0 miles per day, with 96.7% (416/430) driving daily or every other day. Although 26.0% (112/430) had insomnia (ISI≥8), 19.3% (83/430) had daytime drowsiness (ESS≥10), and 19.9% (84/422) had high sleep apnea risk (SACS>15), the median scores for the ISI, ESS, and SACS were normal at 3.0, 6.0, and 8.0, respectively, and only 5.1% reported drowsy driving. Over a period of up to 2 years, 24.9% (104/418) and 51.4% (215/418) of participants had a composite I and II driving event, respectively. In unadjusted and adjusted multivariable models, insomnia, daytime drowsiness, and high sleep apnea risk were not associated with a composite I or II driving event.

CONCLUSION

In a predominantly male cohort of active older drivers, sleep disturbances were mild and not associated with adverse driving events. Accordingly, and because older persons are known to self-regulate driving practices, future studies should evaluate whether sleep disturbances are more important as a mechanism that underlies driving cessation rather than compromising driving safety.

The relationship between benzodiazepine use and traffic accidents: A systematic literature review

In many countries, benzodiazepines are the most commonly used and misused psychoactive medicinal drugs. Results of epidemiological studies investigating the association between benzodiazepine use and traffic accidents seem to be inconclusive or inconsistent at first sight. However, the outcome of epidemiological studies may be influenced by several methodological factors like study design, study population, exposure measurement, outcome definitions and possible confounders. Our objective was to conduct a systematic literature review of epidemiological studies that investigated the association between benzodiazepine use and traffic accidents, including related outcomes like culpability and injury or accident severity. We searched EMBASE, PubMed and Forensic Science Abstracts 3/0 (FORS) for references included in these databases at 1 June 2009 using the term 'benzodiazepines' in combination with 'driving performance' or 'accident risk' or 'traffic accident'. For inclusion in this review, the study design had to be comparative, include road users involved in accidents and provide specific data about benzodiazepines. Sixty-six studies were included in the review. The study populations varied from the general (driving) population, accident-involved road users with or without injury and persons admitted to a hospital to fatally injured accident-involved drivers. Exposure assessment was performed by using toxicological results, prescription data or questionnaires. The divergent study populations and comparison groups and the variety of methods used to express the outcome of interest hampered comparison between results. Evidence is growing that exposure to benzodiazepines is related to increased accident risk. The literature indicates that the greatest accident risk is associated with the use of long half-life benzodiazepines, increasing dosage and the first few weeks of use of benzodiazepines. Clear evidence of increased culpability associated with benzodiazepine use is scarce. More research has to be done to elucidate the relationship between benzodiazepine use and injury severity.

Use of benzodiazepines, hypnotics, and anxiolytics in major depressive disorder: association with chronic pain diseases

We examined the use of benzodiazepines (BZD), hypnotics, and anxiolytics and their associations with chronic pain diseases (CPD) in patients with major depressive disorder (MDD). A retrospective analysis of 153,913 MDD patients (18-64 years) in a large administrative insured claims database during the year 2006 was performed. Results showed that during the study year, 33.1% of the patients had been prescribed BZD; 16.9%, hypnotics; and 6.1%, anxiolytics. The use of BZD and hypnotics increased with age. Patients with CPD were more likely than those without CPD to use BZD (41.2% vs. 27.0%, p < 0.001), hypnotics (21.7% vs. 13.3%, p < 0.001), and anxiolytics (7.8% vs. 4.8%, p < 0.01). After adjustment for demographics and comorbidities, CPD was still significantly associated with increased use of BZD (OR = 1.62), hypnotics (OR = 1.49), and anxiolytics (OR = 1.51). Further research is needed to examine the long-term benefits and risks of BZD and hypnotics in the treatment of MDD and CPD.

Effectively detect dependence on benzodiazepines among community-dwelling seniors by asking only two questions

Consumption of benzodiazepines (BZDs) is common among seniors. When used over a long period of time, BZDs can induce dependence. The present study aimed to equip nurses with valid screening questions for detecting BZD dependence among seniors, applicable to clinical practice and based on the DSM-IV-TR version. A random sample of 707 BZD users aged 65 years and over was screened for BZD dependence using the DSM-IV-TR criteria for substance dependence. To predict a diagnosis of BZDs dependence, sensitivity and specificity were computed for each pair of items. Results showed that an affirmative answer to 'Have you try to stop taking this medication?' and 'Over the past 12 months, have you noticed any decrease in the effect of this medication?' led to a sensitivity of 97.1% and a specificity of 94.9% to detect BZD dependence. Asking these two simple questions can be easily integrated into clinical practice and have considerable potential for identifying cases of BZD dependence.

The prevalence of benzodiazepine dependence among community-dwelling older adult users in Quebec according to typical and atypical criteria

BACKGROUND

Use of benzodiazepines, common among older people, may lead to substance dependence. DSM-IV-TR criteria for this iatrogenic problem may apply poorly to older persons following a physician-prescribed regimen. This study, first of its kind, aimed to determine the prevalence rate of benzodiazepine dependence in older persons according to DSM-IV-TR and other atypical criteria.

METHODS

Descriptive study based on face-to-face interviews conducted in the homes of 2,785 persons aged 65 years or older who were randomly selected from across the province of Quebec, Canada.

RESULTS

Use of benzodiazepines was reported by 25.4% of respondents. Among them, 9.5% met DSM-IV-TR criteria for substance dependence. However, 43% of users reported being dependent, and one third agreed that it would be a good thing to stop taking benzodiazepines.

INTERPRETATION

Benzodiazepine substance dependence is established at one tenth of community-dwelling older persons taking these medications, although a much larger proportion self-labels as dependent.

A case-crossover study of sleep and work hours and the risk of road traffic accidents

STUDY OBJECTIVES

Sleepiness, prolonged wakefulness, and extended work hours have been associated with increased risk of injuries and road accidents. The authors' objective was to study the relation between those factors and road accidents using a case-crossover design, effective in estimating the risk of acute events associated with transient, short effect exposures.

DESIGN

Five hundred seventy-four injured drivers presenting for care after road accidents to the Emergency Room of Udine, Italy, were enrolled in the study from March 2007 to March 2008. Sleep, work, and driving patterns in the 48 h before the accident were assessed through an interview.

MEASUREMENTS AND RESULTS

The relative risk (RR) of accident associated with each exposure was estimated using the case-crossover matched pair interval approach. Sleeping > or = 11 h daily was associated with a decrease of the RR, as was sleeping less than usual. Being awake > or = 16 h and, possibly, working > 12 h daily were associated with increases in the RR.

CONCLUSIONS

Extended work hours and prolonged wakefulness increase the risk of road accidents and suggest that awareness should be raised among drivers. The findings regarding acute sleep amount are less clear, possibly due to an effect of chronic sleep loss.

The effects of acute treatment with tandospirone, diazepam, and placebo on driving performance and cognitive function in healthy volunteers

OBJECTIVE

To assess the effects of two anxiolytics, diazepam and tandospirone, on driving performance from methodological viewpoints taking frequent rear-end collisions into account.

METHODS

In this double-blinded, three-way crossover trial, 18 healthy males received acute doses of 20 mg tandospirone (TSP), 5 mg diazepam (DZP), and placebo (PCB). The subjects were administered three driving tasks-road tracking, car following, and harsh braking-performed using a driving simulator and three cognitive tasks-Wisconsin Card Sorting Test, Continuous Performance Test, and N-back test-at baseline and at 1 and 4 h post-dosing. The Stanford Sleepiness Scale scores were also assessed.

RESULTS

DZP nonsignificantly increased the percent change of brake reaction time (BRT) as compared to PCB at 4 h post-dosing. TSP nonsignificantly decreased the percent change of BRT as compared to PCB. Consequently, there was a significant difference in the percent change of BRT between DZP and TSP at 4 h post-dosing. For the remaining tasks, no statistically significant effects of treatment were observed.

CONCLUSIONS

Acute doses of DZP significantly impaired the harsh-braking performance as compared to acute doses of TSP. These findings suggest that TSP may be used more safely in patients' driving activities.

Ethanol inhibits in-vitro metabolism of nifedipine, triazolam and testosterone in human liver microsomes

Although extended exposure to ethanol induces CYP3A metabolism in-vivo, the acute effects of ethanol on CYP3A metabolism have not been fully evaluated in-vitro. We assessed the effect of ethanol on CYP3A-mediated biotransformation using human liver microsomes in-vitro with three prototypic CYP3A-mediated reactions: nifedipine to oxidized nifedipine, triazolam to its 1-hydroxy (1-OH TRZ) and 4-hydroxy (4-OH TRZ) metabolites, and testosterone to 6β-hydroxytestosterone (6β-OH TST). Ethanol inhibited metabolism of nifedipine (oxidized nifedipine IC50 3 mg dL−1, where the IC50 value is the inhibitor concentration corresponding to a 50% reduction in metabolite formation velocity), triazolam (1-OH TRZ IC50 1.1 mg dL−1, 4-OH TRZ IC50 2.7 mg dL−1) and testosterone (6β-OH TST IC50 2.4 mg dL−1). The inhibitory potency of ethanol was similar for the three substrates representing the three hypothetical CYP3A substrate categories. The IC50 values obtained were lower than clinically relevant blood alcohol concentrations. In conclusion, ethanol is an inhibitor of human CYP3A metabolism and may contribute to clinically important interactions.

Tolerance, sensitization and dependence to diazepam in Balb/c mice exposed to a novel open space anxiety test

Balb/c mice were exposed to an elevated platform that is extended on two opposite sides with lowered steep slopes. They were tested for 12min per session in 6 successive days. They received i.p. administration of either saline or one dose of diazepam (DZP 0.5, 1, 3mg/kg) in sessions 1-3, and saline in sessions 4 and 5. All groups of mice received a single dose of DZP (1mg/kg) in session 6. DZP produced inverted U-shaped dose-responses on the number of entries into different areas of the apparatus, with a peak in mean response at 1mg/kg whereas its effect on the duration of entries was mostly comparable between the 3 doses. It increased the number of crossings on the surface of the platform and facilitated entries onto the slopes. DZP-treated mice crossed frequently onto and spent longer time on the slopes in sessions 1-3 whereas saline-treated mice remained on the platform in sessions 1-6. Withdrawal of DZP in sessions 4-5 increased the latency of first entry and decreased the number and duration of entries onto the slopes which was reversed with the administration of 1mg/kg of DZP in the next session. This ON-OFF the drug may be due to the half-life of DZP which is very short in mice and rats ( approximately 0.88h). It also indicates that DZP-treated mice did not benefit from previous experience of entries onto the slopes which suggests a possible "state-dependent" effect. Administration of DZP after repeated exposures to the test did not facilitate entries onto the slopes but instead increased significantly the number of crossings on the surface of the platform; this increase was much higher than that observed in mice initially treated with DZP and exposed to the test. There is no evidence of habituation in saline-treated mice: the number of crossings on the platform was comparable between the first 5 sessions of the test. These results demonstrate that repeated exposures to the same anxiogenic environment resulted in avoidance responses developing tolerance and approach responses developing sensitization. They suggest that tolerance and sensitization are two opposite sides of the habituation process to the same stimulus and may account for the maintained state of anxiety.

Medication changes prior to hospitalization for obstructive lung disease: a case-crossover study

BACKGROUND

Hospitalizations have always been seen as a solid outcome parameter in pharmacoepidemiology. However, the period leading to hospitalization and prehospital management of the patient are equally important.

OBJECTIVE

To evaluate medication changes in the period prior to hospitalization for obstructive lung disease and to quantify the association between medication use and the risk of hospitalization.

METHODS

We conducted a case-crossover study using the PHARMO record linkage system, which contains drug dispensing data from community pharmacies and hospital admission data. Patients included in the study were adults hospitalized for obstructive lung disease between 2005 and 2007. The index date of the case period was the date of hospitalization, and control moments were set at 3, 6, 9, and 12 months before admission. For each patient, all prescriptions prior to the date of hospitalization were identified. Medication use was ascertained in a 90-day time window prior to each case or control moment.

RESULTS

We identified 1481 patients who were hospitalized for obstructive lung disease. It appeared that respiratory medication use increased in the 90 days prior to hospitalization. Hospitalization was associated with the use of 3 or more respiratory drugs (OR 2.2; 95% CI 1.8 to 2.8), systemic glucocorticoids (OR 4.5; 95% CI 3.8 to 5.4), and antibiotics (OR 3.1; 95% CI 2.7 to 3.6).

CONCLUSIONS

The use of systemic glucocorticoids, antibiotics, and other respiratory drugs increased prior to hospitalization for obstructive lung disease. These results could be indicative of the development and/or treatment of an exacerbation. There is a need for markers to detect exacerbations in an early phase in order to start treatment as early as possible and possibly prevent hospitalizations for obstructive lung disease.

The use of electronic pharmacy data to investigate prescribed medications and fatal motor vehicle crashes in a military population, 2002-2006

The authors examined the association between prescribed medications and fatal motor vehicle crashes (MVCs) in an active duty military population between 2002 and 2006. Using a case-control design, MVC deaths were ascertained using a military mortality registry, and an integrated health system database provided information on health system eligibility, pharmacy transactions, and medical encounters. Cases and controls were matched on comparable observation time outside periods of deployment. Among selected categories, only one, antidepressant medications, was an independent predictor of fatal MVC (odds ratio, 3.19; 95% confidence interval, 1.01-10.07). Male gender, Black race, enlisted rank, service branch (Navy and Marine Corps), and selected co-morbidities were also independent predictors. Unexpectedly, the odds of younger age quartiles (< 27 years) and history of deployment were reduced for MVC cases. Although results need to be considered in the context of data limitations, the association between prescribed antidepressants and fatal MVC may reflect unmeasured co-morbidities, such as combined effects of prescribed and over-the-counter medications and/or alcohol or other substance abuse. Younger individuals, representing new military accessions in training or returning from deployment with serious injuries, may have fewer opportunities to operate vehicles, or targeted efforts to reduce MVC following deployment may be showing a positive effect.

Residual effects of hypnotic drugs in aging drivers submitted to simulated accident scenarios: an exploratory study

RATIONALE

The effects of hypnotic drugs on driving performance are most often evaluated on young healthy subjects by using a monotonous motorway driving test. The effects of drugs in urban driving situations have not yet been evaluated in any age group. Our objectives were to assess residual effects of the most prescribed hypnotics, zolpidem and zopiclone, on older middle-age drivers' capacities in an urban situation.

MATERIALS AND METHODS

Sixteen healthy subjects aged 55 to 65 years underwent this double-blind, balanced, cross-over study. Zopiclone (7.5 mg), zolpidem (10 mg), and flunitrazepam (1 mg; used as positive control) or a placebo were administered at each subject's home at 11:00 PM: under the supervision of an investigator. The next morning, the subjects had to drive in a simulated urban environment where accident scenarios were introduced. Accident scenarios were implemented using data from real accident cases.

RESULTS

Hypnotics did not significantly increase the number of collisions. However, significantly higher speeds were found with zopiclone and flunitrazepam; moreover, zolpidem and zopiclone induced modifications of the lateral position of the car on the road.

CONCLUSIONS

This study did not reveal any major residual effects of the hypnotics studied on driving performance in aging drivers. However, the urban driving situations used here for the first time in the evaluation of drugs revealed some modifications in driving habits which could lead to risky behavior. It thus appears that urban driving simulations are useful for gaining knowledge about the effects of drugs on driving behavior.

Factors associated with benzodiazepine dependence among community-dwelling seniors

BACKGROUND

Benzodiazepine (BZD) dependence among seniors is an understudied problem.

OBJECTIVE

Identify the factors associated with BZD dependence.

METHOD

Face-to-face computer-assisted interviews were conducted in the homes of 2,785 persons aged 65 years or older, randomly selected.

RESULTS

Nine-and-a-half percent of BZD users met DSM-IV-TR criteria for BZD dependence. Factors associated with BZD dependence are being a woman, and having cognitive impairment, panic disorders, suicidal ideations, and a degree of embarrassment in obtaining help for emotional problem.

DISCUSSION

Nurses should be better positioned to identify those elderly users of BZDs who are more likely to be dependent and to address the problem through BZD withdrawal program.

Problems associated with long-term treatment with selective serotonin reuptake inhibitors

Although the selective serotonin reuptake inhibitors (SSRIs), which are now widely used as a first-line treatment for depression and many other psychiatric conditions, are generally well tolerated, they are not devoid of side effects. Most short-term treatment-related side effects of SSRIs are transient and disappear after a few days or weeks. However, following long-term treatment with the SSRIs, some serious adverse events may occur. Some of them can be difficult to recognise because they can resemble residual symptoms of depression. The most serious can be life threatening. They all have a negative influence on the patient's quality of life and are frequently a prime reason for a lack of long-term compliance with the associated increased risk of recurrence of a depressive episode. This article is an overview of the more common adverse events, which are seen with non-acute treatment with the SSRIs.

The impact of medicinal drugs on traffic safety: a systematic review of epidemiological studies

PURPOSE

To evaluate the quality of epidemiological research into effects of medicinal drugs on traffic safety and the current knowledge in this area.

DATA SOURCES

The bibliographic search was done in Medline electronic database using the keywords: ((accident* or crash*) and traffic and drug*) leading to 1141 references. Additional references were retrieved from the Safetylit website and the reference lists of selected studies. Original articles published in English or French, between 1 April 1979 and 31 July 2008, were considered for inclusion. We excluded descriptive studies, studies limited to alcohol or illicit drug involvement and investigations of injuries other than from traffic crashes. Studies based on laboratory tests, driving simulators or on-the-road driving tests were also excluded. Eligible studies had to evaluate the causal relationship between the use of medicinal drugs and the risk of traffic crashes. Study quality was assessed by two independent experts, according to a grid adapted from the strengthening the reporting of observational studies in epidemiology (STROBE) statement.

RESULTS

Twenty two studies of variable methodological quality were included. Definition of drug exposure varied across studies and depended on the data sources. Potential confounding due to the interaction between the effects of the medicinal drug and disease-related symptoms was often not controlled. The risk of motor-vehicle crashes related to benzodiazepines has been amply studied and demonstrated. Results for other medicinal drugs remain controversial.

CONCLUSION

There is a need for large studies, investigating the role of individual substances in the risk of road traffic crashes.

A case-crossover study of alcohol consumption, meals and the risk of road traffic crashes

Background

The case-crossover (CC) design has proved effective to investigate the association between alcohol use and injuries in general, but has never been applied to study alcohol use and road traffic crashes (RTCs) specifically. This study aims at investigating the association between alcohol and meal consumption and the risk of RTCs using intrapersonal comparisons of subjects while driving.

Methods

Drivers admitted to an Italian emergency room (ER) after RTCs in 2007 were interviewed about personal, vehicle, and crash characteristics as well as hourly patterns of driving, and alcohol and food intake in the 24 hours before the crash. The odds ratio (OR) of a RTC was estimated through a CC, matched pair interval approach. Alcohol and meal consumption 6 and 2 hours before the RTC (case exposure window) were compared with exposures in earlier control windows of analogous length.

Results

Of 574 patients enrolled, 326 (56.8%) reported previous driving from 6 to 18 hours before the RTC and were eligible for analysis. The ORs (mutually adjusted) were 2.25 (95%CI 1.11-4.57) for alcohol and 0.94 (0.47-1.88) for meals. OR for alcohol was already increased at low (1-2 units) doses - 2.17 (1.03-4.57) and the trend of increase for each unit was significant - 1.64 (95%CI 1.05-2.57). In drivers at fault the OR for alcohol was 21.22 (2.31-194.79). The OR estimate for meal consumption seemed to increase in case of previous sleep deprivation, 2.06 (0.25-17.00).

Conclusion

Each single unit of acute alcohol consumption increases the risk of RTCs, in contrast with the 'legal' threshold allowed in some countries. Meal consumption is not associated with RTCs, but its combined effects with sleepiness need further elucidation.