Prevalence of medicinal drugs in suspected impaired drivers and a comparison with the use in the general Dutch population

Driving Under the Influence of Cannabis: A Framework for Future Policy

Marijuana is the most widely consumed illicit substance in the United States, and an increasing number of states have legalized it for both medicinal and recreational purposes. As it becomes more readily available, there will be a concurrent rise in the number of users and, consequently, the number of motor vehicle operators driving under the influence. This article examines the cognitive and psychomotor effects of cannabis, as well as current policy concerning driving under the influence of drugs. The authors performed a MEDLINE search on the epidemiology of cannabis use, its cognitive and psychomotor effects, and policies regarding driving under the influence of drugs. Twenty-eight epidemiological studies, 16 acute cognitive and psychomotor studies, 8 chronic cognitive and psychomotor studies, and pertinent state and federal laws and policies were reviewed. These search results revealed that marijuana use is associated with significant cognitive and psychomotor effects. In addition, the legalization of marijuana varies from state to state, as do the laws pertaining to driving under the influence of drugs. Marijuana is a commonly found illicit substance in motor vehicle operators driving under the influence of drugs. Current evidence shows that blood levels of tetrahydrocannabinol do not correlate well with the level of impairment. In addition, although acute infrequent use of cannabis typically leads to cognitive and psychomotor impairment, this is not consistently the case for chronic heavy use. To establish the framework for driving under the influence of cannabis policy, we must review the current published evidence and examine existing policy at state and federal levels.

Trends and correlates of driving under the influence of alcohol among different types of adult substance users in the United States: a national survey study

Background

Despite a decrease in driving under the influence of alcohol (DUIA) prevalence over the past decades, DUIA prevalence still remains high in the United States. To date, there is limited research examining whether different types of substance users have different trends in DUIA. This study sought to assess trends and variables associated with DUIA by substance use type.

Methods

National Survey on Drug Use and Health (NSDUH) is a cross-sectional, nationally representative population-based survey. By using the NSDUH 2008–2014, we performed the Joinpoint analysis to identify time trends of DUIA in each group of substance users (aged ≥18 years). Logistic regression analysis was used to explore association between substance use type and DUIA and to identify variables associated with DUIA.

Results

Adults who reported alcohol or drug use in the past year were classified into different groups based on past-year substance use status: alcohol use only (n = 141,521) and drug use regardless alcohol use. Drug users included prescription opioids only (n = 5337), marijuana only (n = 32,206), other single drug (n = 3789), prescription opioids-marijuana (n = 3921), multiple prescription drugs (n = 1267), and other multiple drugs (n = 18,432). The Joinpoint analysis showed that DUIA prevalence decreased significantly from 2008 to 2014 among alcohol only users (Average Annual Percent Change [AAPC] = − 2.8), prescription opioids only users (AAPC = -5.4), marijuana only users (AAPC = -5.0), prescription opioids-marijuana users (AAPC = -6.5), multiple prescription drug users (AAPC = -7.4), and other multiple drug users (AAPC = -3.2). Although the estimate was not statistically significant, other single drug users showed a decreasing trend (AAPC = -0.9). Substance use type was significantly associated with DUIA in the adjusted logistic regression. All drug use groups, relative to the alcohol only group, had elevated odds of DUIA, and the odds were especially elevated for the multiple drug use groups (prescription opioids-marijuana, adjusted odds ratio [AOR] = 2.71; multiple prescription drugs, AOR = 2.83; and other multiple drugs, AOR = 3.68). Additionally, younger age, male sex, being white, higher income, and alcohol abuse/dependence were positively associated with DUIA.

Conclusions

DUIA prevalence decreased over time and the magnitude of this reduction differed by substance use type. DUIA interventions need to be tailored to substance use type and individual characteristics.

The Problem of Benzodiazepine Use and Its Extent in the Driver Population: A Population-Based Registry Study

Background: Benzodiazepines are driving-impairing medicines (DIM). This study presents current consumption of dispensed benzodiazepines in the Spanish general population, with a focus in pattern of use and concomitant medicines consumed with. Methods: A population-based registry study was carried out to assess the year-2016 granted benzodiazepines dispensation in Castile and León. Weighting was performed to obtain the adjusted benzodiazepine consumption for licensed drivers according to age and gender using our national drivers' license census data. Results: Benzodiazepines were used by 15.38% of the general population and 10.97% of drivers. Nearly 2% of the population and more than 1% of drivers took these medicines every day. The amount consumed (until 3 or more benzodiazepines per day) and concomitant use of other DIM were also higher. Women were the most frequent consumers, and anxiolytic use was usual. Consumption increases with age, but there were differences between men and women drivers from 60 years old. Conclusions: The current use of benzodiazepines must serve to awareness of the healthcare personnel, patients, and authorities on their risks, above all on the road safety.

Comparing the effects of oxazepam and diazepam in actual highway driving and neurocognitive test performance: a validation study

OBJECTIVE

Screening of drug-induced performance impairment is needed to provide meaningful information for users and prescribers regarding the impact of drugs on driving. The main objective was to assess the effects of oxazepam 10 mg (OXA10), oxazepam 30 mg (OXA30), and diazepam 10 mg (DIA10) on standard deviation of lateral position (SDLP) in a highway driving test in actual traffic and to determine the ability of eight neurocognitive tests to detect comparable effects.

METHODS

Twenty-three healthy volunteers participated in a four-way double-blind, placebo-controlled, crossover study. The highway driving test was conducted between 4 and 5 h after drug intake. A range of neurocognitive tests was conducted before and after driving, 2 and 6 h post-treatment, respectively.

RESULTS

Mean SDLP increased by 1.83, 3.03, and 7.57 cm after OXA10, DIA10, and OXA30, respectively. At 2 h post-treatment, all neurocognitive tests, except the useful field of view, showed performance impairment in all active treatments. Effect sizes (ES) were moderate for OXA10, large ES for DIA10, and largest ES for OXA30. Modest correlations were found between changes in SDLP and performance in the attention network test (ANT), the divided attention test (DAT), and the psychomotor vigilance test (PVT).

CONCLUSION

OXA10 caused minor, DIA10 moderate, and OXA30 severe driving impairment. No neurocognitive test was both dose dependently sensitive and able to be associated with driving impairment. No neurocognitive test can replace the on-the-road highway driving test.

Use of driving-impairing medicines by a Spanish population: a population-based registry study

OBJECTIVE

To assess the use of driving-impairing medicines (DIM) in the general population with special reference to length of use and concomitant use.

DESIGN

Population-based registry study.

SETTING

The year 2015 granted medicines consumption data recorded in the Castile and León (Spain) medicine dispensation registry was consulted.

PARTICIPANTS

Medicines and DIM consumers from a Spanish population (Castile and León: 2.4 million inhabitants).

EXPOSURE

Medicines and DIM consumption. Patterns of use by age and gender based on the length of use (acute: 1-7 days, subacute: 8-29 days and chronic use: ≥30 days) were of interest. Estimations regarding the distribution of licensed drivers by age and gender were employed to determine the patterns of use of DIM.

RESULTS

DIM were consumed by 34.4% (95% CI 34.3% to 34.5%) of the general population in 2015, more commonly with regularity (chronic use: 22.5% vs acute use: 5.3%) and more frequently by the elderly. On average, 2.3 DIM per person were dispensed, particularly to chronic users (2.8 DIM per person). Age and gender distribution differences were observed between the Castile and León medicine dispensation registry data and the drivers' license census data. Of all DIM dispensed, 83.8% were in the Anatomical Therapeutic Chemical code group nervous system medicines (N), which were prescribed to 29.2% of the population.

CONCLUSIONS

The use of DIM was frequent in the general population. Chronic use was common, but acute and subacute use should also be considered. This finding highlights the need to make patients, health professionals, health providers, medicine regulatory agencies and policy-makers at large aware of the role DIM play in traffic safety.

Drugged Drivers Blood Concentrations in England and Wales Prior to the Introduction of Per Se Limits

This report details the blood concentration of drugs found in motorists suspected of driving under the influence of drugs from 2010 to 2012 in England and Wales. This study was carried out as new legislation has come into place, setting fixed blood concentration limits for drugs in motorists. These include a cannabis (Δ9-THC) blood concentration of 2 µg/L, amphetamine 250 µg/L, benzoylecgonine (BZE) 50 µg/L, cocaine 10 µg/L, 6-monoacetylmorphine 5 µg/L, morphine 80 µg/L, diazepam 550 µg/L and methadone 500 µg/L. Samples were screened for opiates, methadone, benzodiazepines, cannabinoids, cocaine, amphetamines and methamphetamine. Cannabinoids were the most prevalent drug group (29.7%) followed by benzodiazepines (22.7%), opiates (18.8%), cocaine (16.3%), amphetamine (7%) and methadone (5.6%). The analytical results are compared with the new per se limits to give a reference of drug concentrations prior to this legislation coming into effect. Our studies show that 64.9% of the cannabis samples, 59.1% of the cocaine samples and 94.6% of the BZE samples would be above the new per se limits set under Section 5a of the Road Traffic Act. In contrast, the medicinal drugs such as benzodiazepines and opiates (morphine) were predominantly detected at concentrations below the new per se limit. Given its medical applications, amphetamines appear to have been grouped with the medicinal type drugs, with our data showing that 25.2% of the amphetamine positive samples would exceed the new specified limit. These data show that samples containing medicinal and prescription drugs are likely to be detected below the new legal limits, while illicit drugs were typically found at concentrations above the new specified limits.

Non-prescribed use of psychoactive prescription drugs among drug-impaired drivers in Sweden

AIMS

To determine the prevalence of non-prescribed drug use among subjects suspected of drug-impaired driving with a psychoactive prescription drug, and to identify associated factors.

METHODS

Subjects investigated for drug-impaired driving in Sweden during 2006-2009 with a confirmed intake of diazepam, flunitrazepam, tramadol, zolpidem or zopiclone were identified using the Swedish Forensic Toxicology Database. Information on dispensed prescription drugs was retrieved from the Swedish Prescribed Drug Register. Non-prescribed use was our outcome, defined as a psychoactive prescription drug intake confirmed by toxicological analysis in a subject by whom it was not dispensed in the 12 months preceding the sampling. Prevalence proportions were calculated for each drug and logistic regression was used to identify associated factors.

RESULTS

In total, 2225 subjects were included. The median age (range) was 34 (15-80) years and 1864 (83.8%) subjects were male. Non-prescribed use was found in 1513 subjects (58.7%); for flunitrazepam 103 (76.3%), diazepam 1098 (74.1%), tramadol 192 (40.3%), zopiclone 60 (29.7%), and zolpidem 60 (21.2%) subjects, respectively. Younger age and multiple-substance use were associated with non-prescribed use, whereas ongoing treatment with other psychoactive drugs was negatively associated with non-prescribed use.

CONCLUSIONS

Non-prescribed use of psychoactive prescription drugs was common in subjects suspected of drug-impaired driving and was more frequent for benzodiazepines and tramadol compared to zolpidem and zopiclone. The young and multi-substance users were more likely, whereas subjects with ongoing prescribed treatment with other psychoactive drugs were less likely, to use non-prescribed drugs.

The use of psychoactive prescription drugs among DUI suspects

BACKGROUND

The study seeks to increase understanding of the use of psychoactive prescription drugs among persons suspected of driving under the influence (DUI). We studied whether the use of prescribed psychoactive medication was associated with DUI, and examined the difference in the use of prescription drugs between DUI recidivists and those arrested only once.

METHODS

In this register-based study, persons suspected of DUI (n=29470) were drawn from the Register of DUI suspects, and an age- and gender-matched reference population (n=30043) was drawn from the Finnish general population. Data on prescription drug use was obtained by linkage to the National Prescription Register. The associations of DUI arrest and use of psychoactive prescription drugs in different DUI groups (findings for alcohol only, prescription drugs, prescription drugs and alcohol, illicit drugs) were estimated by using mixed-effect logistic regression.

RESULTS

The use of psychoactive prescription drugs and DUI appeared to be strongly associated, with DUI suspects significantly more likely to use psychoactive prescription drugs compared to the reference population. Gender differences existed, with the use of benzodiazepines being more common among female DUI suspects. Moreover, DUI recidivists were more likely to use psychoactive prescription drugs compared to those arrested only once.

CONCLUSIONS

In addition to alcohol and/or illicit drug use, a significant proportion of DUI suspects were using psychoactive prescription drugs. When prescribing psychoactive medication, especially benzodiazepines, physicians are challenged to screen for possible substance use problems and also to monitor for patients' alcohol or illicit drug use while being medicated.

Sedative Hypnotic Medication Use and the Risk of Motor Vehicle Crash

OBJECTIVES

We sought to estimate the association between sedative hypnotic use and motor vehicle crash risk.

METHODS

We conducted a new user cohort study of 409 171 adults in an integrated health care system. Health plan data were linked to driver license and collision records. Participants were aged 21 years or older, licensed to drive in Washington State, had at least 1 year of continuous enrollment between 2003 and 2008, and were followed until death, disenrollment, or study end. We used proportional hazards regression to estimate the risk of crash associated with 3 sedatives.

RESULTS

We found 5.8% of patients received new sedative prescriptions, with 11 197 person-years of exposure. New users of sedatives were associated with an increased risk of crash relative to nonuse: temazepam hazard ratio (HR) = 1.27 (95% confidence interval [CI] = 0.85, 1.91), trazodone HR = 1.91 (95% CI = 1.62, 2.25), and zolpidem HR = 2.20 (95% CI = 1.64, 2.95). These risk estimates are equivalent to blood alcohol concentration levels between 0.06% and 0.11%.

CONCLUSIONS

New use of sedative hypnotics is associated with increased motor vehicle crash risk. Clinicians initiating sedative hypnotic treatment should consider length of treatment and counseling on driving risk.