Impairment based legislative limits for driving under the influence of non-alcohol drugs in Norway

Detection of cocaine 24 h after administration before nasotracheal intubation

BACKGROUND

Cocaine may be applied to decongest the nasal mucosa before nasotracheal intubation, but patients risk a criminal offence if cocaine is detected when patients drive a car shortly after surgery. We aimed to evaluate whether benzoylecgonine levels in saliva exceeded the cut-off point 24 h after administration in patients undergoing nasotracheal intubation and whether cocaine would be detectable above the Danish legal fixed limit in blood samples 1 and 24 h after surgery.

METHODS

We conducted a prospective study following approval from the local research ethics committee and the national medicine agency. Written informed consent was obtained from all patients. We included patients scheduled for surgery under general anaesthesia with nasotracheal intubation. They received 80 mg cocaine as a nasal spray 5 min before induction and nasotracheal intubation. The primary outcome was a dichotomous assessment of benzoylecgonine levels in saliva samples measured 24 h after administration of nasal cocaine with a cut-off limit of 200 ng/mL. Secondary outcomes were dichotomous assessments of cocaine in whole blood samples measured 1 and 24 h after administration of nasal cocaine with a cut-off limit of 0.01 mg/kg.

RESULTS

Overall, 70 patients had valid saliva samples and 75 had valid blood samples 24 h after cocaine administration. Benzoylecgonine in saliva was traceable above the cut-off in 9/70 patients (13%; CI95%: 6% to 23%), and cocaine in blood was detected above the cut-off in 2/75 patients (3%; CI95%: 0.3% to 9%).

CONCLUSION

We found benzoylecgonine traceable in saliva in 13% of patients and cocaine traceable in blood in 3% of patients 24 h after administration of 80 mg nasal cocaine. Patients should be informed when receiving cocaine and advised not to drive for at least 24 h.

All-cause and cause-specific mortality among individuals imprisoned for driving under the influence of alcohol and drugs in Norway (2000-2016): a retrospective cohort study

AIMS

To describe all-cause and cause-specific mortality and to investigate factors associated with mortality among individuals imprisoned for driving under the influence (DUI) of alcohol and psychoactive drugs in the Norwegian prison population.

DESIGN

Retrospective cohort study. The Norwegian prison registry was linked to the Norwegian Cause of Death Registry (2000-2016).

SETTING

Norway.

PARTICIPANTS/CASES

The cohort consisted of 96 856 individuals imprisoned in Norway over a 17-year period obtained from the Norwegian prison registry.

PRIMARY AND SECONDARY OUTCOME MEASURES

Adjusted ORs (aOR) with 95% CI were calculated for death due to any, natural and unnatural causes of death. Analyses were stratified according to DUI convictions: no DUI convictions, only DUI convictions (DUI only), DUI and at least one other drug and alcohol conviction (DUI drug), and DUI and at least one conviction other than drug and alcohol conviction (DUI other).

RESULTS

In total, 29.3% individuals had one or more imprisonments for DUI. The risk of all-cause mortality was elevated for those convicted for DUI, but only in combination with other types of crimes (DUI drug: aOR=1.5, 95% CI 1.4 to 1.6, DUI other: aOR=1.2, 95% CI 1.1 to 1.4). The risk of death from natural causes was significantly elevated for DUI drug (aOR: 1.8, 95% CI 1.6 to 2.0) and for DUI other (aOR=1.3, 95% CI 1.1 to 1.6). The risk of death from unnatural causes was lower for DUI only (aOR=0.8, 95% CI 0.7 to 0.9) and elevated for DUI drug (aOR=1.5, 95% CI 1.3 to 1.6).

CONCLUSIONS

The risk of all-cause mortality was significantly elevated for those convicted of DUI, but only in combination with other types of crimes.

Prevalence of use and impairment from drugs and alcohol among trauma patients: A national prospective observational study

BACKGROUND

Being under the influence of psychoactive substances increases the risk of involvement in and dying from a traumatic event. The study is a prospective population-based observational study that aims to determine the prevalence of use and likely impairment from psychoactive substances among patients with suspected severe traumatic injury.

METHOD

This study was conducted at 35 of 38 Norwegian trauma hospitals from 1 March 2019 to 29 February 2020. All trauma admissions for patients aged ≥ 16 years admitted via trauma team activation during the study period were eligible for inclusion. Blood samples collected on admission were analysed for alcohol, benzodiazepines, benzodiazepine-like hypnotics (Z-drugs), opioids, stimulants, and cannabis (tetrahydrocannabinol).

RESULTS

Of the 4878 trauma admissions included, psychoactive substances were detected in 1714 (35 %) and in 771 (45 %) of these, a combination of two or more psychoactive substances was detected. Regarding the level of impairment, 1373 (28 %) admissions revealed a concentration of one or more psychoactive substances indicating likely impairment, and 1052 (22 %) highly impairment. Alcohol was found in 1009 (21 %) admissions, benzodiazepines and Z-drugs in 613 (13 %), opioids in 467 (10 %), cannabis in 352 (7 %), and stimulants in 371 (8 %). Men aged 27-43 years and patients with violence-related trauma had the highest prevalence of psychoactive substance use with respectively 424 (50 %) and 275 (80 %) testing positive for one or more compounds.

CONCLUSION

The results revealed psychoactive substances in 35 % of trauma admissions, 80 % of which were likely impaired at the time of traumatic injury. A combination of several psychoactive substances was common, and younger males and patients with violence-related injuries were most often impaired. Injury prevention strategies should focus on high-risk groups and involve the prescription of controlled substances. We should consider toxicological screening in trauma admissions and incorporation of toxicological data into trauma registries.

A two-sample approach to retrograde extrapolation of blood THC concentrations - Is it feasible?

BACKGROUND

Retrograde extrapolation of drug concentrations in blood can be relevant in cases of drug-impaired driving and is regularly used in forensic toxicology in Norway. Δ9-tetrahydrocannabinol (THC) has complex, multi-compartmental pharmacokinetics, which makes retrograde extrapolation of blood THC concentrations problematic. In the present study, we evaluated an approach to retrograde extrapolation in which momentary rates of decrease of THC were estimated from two consecutive blood samples in apprehended drivers.

MATERIAL AND METHODS

Data were collected from apprehended drivers in Norway 2000-2020. We included 548 cases in which THC was detected in two consecutive blood samples collected ≥ 20 min apart. THC concentrations were measured by GC-MS and UHPLC-MS/MS. In each case, THC concentrations and the time between the two sampling points (Δt) were used to estimate the rate constant k. The relationship between THC concentration and k was modelled by linear regression.

RESULTS

The median Δt was 31 min (interquartile range, IQR = 9). The median blood THC concentration was 2.4 μg/L (IQR = 3.4) at the first sampling point and 2.3 μg/L (IQR =3.1) at the second. The concentration decreased in 62% and increased in 38% of all cases. However, considering measurement uncertainty, the changes were not statistically significant in 87% of cases. The mean of k was 0.12 h-1, corresponding to an apparent t1/2 of 6.0 h. The t1/2 predicted from linear regression of k against THC concentration ranged from 0.93 to 13 h for the highest and lowest concentrations observed (36 and 0.63 μg/L, respectively). The time from driving to blood collection had a median of 1.7 h (IQR = 1.5), and did not correlate with k.

CONCLUSIONS

The apparent t1/2 of THC calculated from the mean of k was 6.0 h, which is shorter than the terminal elimination t1/2 suggested in previous population studies. This indicates that blood samples were often taken during the late distribution phase of THC. Because Δt was short relative to the rates of decrease expected in the late distribution and elimination phases, the underlying true concentration changes related to in vivo pharmacokinetics were small and masked by the relatively larger "false" changes introduced by random analytical and pre-analytical error. Therefore, individual values of k calculated from only two blood samples taken a short time apart are unreliable, and a two-sample approach to retrograde extrapolation of THC cannot be recommended.

Crash-involved THC-positive drivers in Norway have a high frequency of polysubstance use

BACKGROUND

Tetrahydrocannabinol (THC) is the most frequently detected drug in blood samples from apprehended drug driving suspects in Norway. This investigation aimed to study the extent of polysubstance use among apprehended crash-involved drivers with THC concentrations above the legal limit and explore the importance of THC in polysubstance cases.

METHODS

We selected all drug driving cases where blood samples had been submitted for forensic toxicology testing after involvement in road traffic crashes during 2013-2020, except drivers who were fatally injured.

RESULTS

Twenty percent (n = 2133) of the 10,520 apprehended crash-involved drivers had concentrations of THC in their blood above the legal limit of 1.3 ng/mL, and 84 % of those also had concentrations of alcohol or other drugs above the legal limits; 61 % for sedatives, 38 % for stimulants, 33 % for alcohol, and 10 % for opioids. The most frequent substance combination was cannabis together with sedatives and stimulants (22.9 %; n = 488). Polysubstance use was least common among drivers under 24 years. The proportion of drivers with THC > 5 ng/mL was highest if the blood sample was collected within 90 min after the crash, and when only THC was detected. There was a statistically significant inverse association between THC > 5 ng/mL and concentrations of alcohol or amphetamines at the highest sanction level.

CONCLUSIONS

Most apprehended crash-involved THC-positive drivers also tested positive for other psychoactive substances. Drivers with high blood THC concentrations had less often high concentrations of other substances; cannabis might then have been a more important contributor to impairment.

An electrochemical aptasensor for Δ9-tetrahydrocannabinol detection in saliva on a microfluidic platform

We present a novel "on-off", cost-effective, rapid electrochemical aptasensor combined with a microfluidics cartridge system for the detection of Δ⁹-THC (Δ⁹-tetrahydrocannabinol) in human saliva via differential pulse voltammetry. The assay relied on the competitive binding between the Δ⁹-THC and a soluble redox indicator methylene blue, using an aptamer selected via FRELEX. We found that the aptasensor can detected 1 nM of Δ⁹-THC in PBS in a three-electrode cell system, while the sensitivity and both the dissociation constant (K_d) and association constant (K_b) were dependent on the aptamer density. The aptamer also showed great affinity towards Δ⁹-THC when tested against cannabinol and cannabidiol. The same limit of detection of 1 nM in PBS was achieved in small volume samples (∼60 μL) using the aptamer-modified gold screen-printed electrodes combined with the microfluidic cartridge setup, however, the presence of 10% raw human saliva had a negative effect which manifested in a 10-fold increase in the LOD due to interfering elements. Filtering the saliva, improved the tested volume to 50% and the LOD to 5 nM of Δ⁹-THC which is lower than the concentrations associated with impairment (6.5-32 nM). The aptasensor showed a good storage capability up to 3 days, however, the reusability significantly dropped from 10 cycles (freshly prepared) to 5 cycles. The results clearly demonstrate the feasibility of the aptasensor platform with the microfluidics chamber towards a point-of-care testing application for the detection of Δ⁹-THC in saliva.

Prevalence of alcohol and drugs among drivers killed in road traffic crashes in Norway during 2011-2020

OBJECTIVE

Driving under the influence of alcohol or drugs is one of the main contributing causes of serious road traffic crashes (RTCs). This study aimed to investigate the involvement of alcohol and drugs in driver fatalities in Norway during 2011-2020 and compare the findings with data from the previous decade.

METHODS

We linked the results of forensic toxicology testing for alcohol and the 17 most commonly used drugs assigned with legal limits with data on fatal road traffic crashes obtained from Statistics Norway and the Norwegian Public Roads Administration.

RESULTS

The number of fatalities had decreased significantly since the previous decade, while the proportion of drivers and riders tested for alcohol and drug use increased. Blood alcohol concentrations at the legal limit or higher were found in 14.4% and psychoactive drugs were detected in 15.8% of the cases; 10.7% tested positive for illicit drugs, and 10.1% for medicinal drugs. The most prevalent illicit drugs were tetrahydrocannabinol (7.9%) and amphetamine/methamphetamine (4.7%), whereas the most prevalent medicinal drugs were clonazepam (3.7%) and diazepam (2.2%).

CONCLUSIONS

There was a marked reduction in the number of motor vehicle drivers killed in RTCs compared with the previous decade, and also a reduction in the prevalence of alcohol. For other substances, there were no marked changes in the prevalence.

Characteristics of crash-involved drink and drug car drivers and motorcyclists

OBJECTIVE

Drug driving is an issue of growing concern among Australian jurisdictions, including South Australia. In order to have an appropriate response to drug driving in regard to policy and enforcement, it is important to have sound knowledge about the patterns of drug use among motorists and the associated risks of this behavior.

METHOD

To this end, this study examined the characteristics of 1,277 hospitalized road users in South Australia in the years 2014 to 2017, with reference to whether or not they tested positive for alcohol or other drugs (the three drugs tested for according to the South Australian Road Traffic Act (1961): THC, methamphetamine, MDMA). This examination used a database combining hospital data, police-reported crash data, licensing information, and the result of alcohol and drug tests conducted by Forensic Science SA.

RESULTS

It was found that more motorists were positive for one or more of the three illicit drugs than for alcohol, reversing long established trends. Comparisons were made between alcohol and drug free motorists, alcohol positive motorists, drug positive motorists, and motorists positive for both drugs and alcohol, with drivers of cars and motorcyclists analyzed separately where possible. Findings include: that those combining drugs and alcohol only comprise a small proportion of hospitalized motorists; that drug drivers tend to be younger than other hospitalized motorists; that drivers are more likely to test positive to alcohol or methamphetamine, while motorcyclists are more likely to test positive to THC; motorists testing positive to drugs and/or alcohol tend to exhibit a range of other risky behaviors; and motorists testing positive to drugs and/or alcohol tend to sustain more severe injuries in the event of a crash.

CONCLUSIONS

Preventing drink and drug driving is important not only for reducing crash numbers but also injury severity in the event of a crash. Substance use differs by road user type and age, which has potential implications for enforcement practices.

High-sensitivity method for the determination of LSD and 2-oxo-3-hydroxy-LSD in oral fluid by liquid chromatography‒tandem mass spectrometry

PURPOSE

We have developed and validated a high-sensitivity method to quantify lysergic acid diethylamide (LSD) and 2-oxo-3-hydroxy-LSD (OH-LSD) in oral fluid samples using liquid-liquid extraction and liquid chromatography-tandem mass spectrometry (LC‒MS/MS). The method was applied to the quantification of both substances in 42 authentic oral fluid samples.

METHODS

A liquid-liquid extraction was performed using 500 µL each of samples (oral fluid samples collected using Quantisal™ device) and dichloromethane/isopropanol mixture (1:1, v/v). Enzymatic hydrolysis was evaluated to cleave glucuronide metabolites.

RESULTS

The limit of quantification was 0.01 ng/mL for both LSD and OH-LSD. The linearity was assessed between 0.01 and 5 ng/mL. Imprecision and bias were not higher than 10.2% for both analytes. Extraction recovery was higher than 69%. The analytes were stable in the autosampler at 10 °C for 24 h, and up to 30 days at 4 and -20 °C. The method was applied to the analysis of 42 oral fluid samples. LSD was detected in all samples (concentrations between 0.02 and 175 ng/mL), and OH-LSD was detected in 20 samples (concentrations between 0.01 and 1.53 ng/mL).

CONCLUSIONS

A high-sensitive method was fully validated and applied to authentic samples. To our knowledge, this is the first work to report concentrations of LSD and OH-LSD in authentic oral fluid samples.

Development of a plant-produced recombinant monoclonal antibody against Δ-9-tetrahydrocannabinol (Δ9-THC) for immunoassay application

•

This is the first report of the production of anti- Δ9-THC mAb in N. benthamiana which are the cost-effective and rapidly production platform.

•

Moreover, plant-produced mAb provide the efficiency against Δ9-THC and it can be applied for the further immunoassay application.

Δ-9-tetrahydrocannabinol (Δ9-THC) is mainly a psychoactive compound in the cannabis plant. The immunoassay, an alternative method to HPLC and GC, can be used to analyze and measure Δ9-THC. This method provides high sensitivity and specificity by using antibodies specific to the desired substances. Currently, plants provide several benefits over traditional expression platforms to produce recombinant antibodies, such as lower production costs and scalability. Therefore, this study aims to produce a recombinant anti-Δ9-THC monoclonal antibody (mAb) with transient expression using N. benthamiana. The highest expression level of the plant-produced mAb was estimated to be 0.33 ug/g leaf fresh weight. Our results demonstrate that the antibody provided in vitro affinity binding related to Δ9-THC and the metabolites of Δ9-THC, such as cannabinol (CBN). Moreover, the antibody also showed binding efficiency with Δ9-THC in cannabis extract. Moreover, plant-produced mAbs provide efficiency against Δ9-THC and can be applied for further immunoassay applications.

Young adults in motor vehicle collisions in Norway: user safety errors observed in majority of cases with severe or fatal injuries

PURPOSE

We performed a multidisciplinary investigation of young adults involved in motor vehicle collisions (MVCs) to elucidate injury mechanisms and the role of passive safety equipment such as seat belts and airbags.

METHODS

MVCs resulting in death or serious injuries to the driver or passengers aged 16-24 years in southeastern Norway during 2013-2016 were investigated upon informed consent. We assessed the crash scene, the motor vehicle (MV) interior and exterior, and analyzed data from medical records, forensic autopsies and reports from police and civil road authorities.

RESULTS

This study included 229 young adult occupants involved in 212 MVCs. The Maximum Abbreviated Injury Scale (MAIS) score was ≥2 in 111 occupants, of which 22 were fatalities. In 59% (65/111) of the cases with MAIS score ≥2 injuries, safety errors and occupant protection inadequacies were considered to have contributed to the injury outcome. Common errors were seatbelt non-use and misuse, carrying insecure luggage, and the seat back being too reclined. MAIS score ≥2 head/neck injuries were observed in side impacts despite correct seatbelt use, related to older MVs lacking side airbag curtains. The independent risk factors for MAIS score ≥2 injuries included not using a seatbelt, driving under the influence of alcohol or drugs, nighttime driving, side impacts, heavy collision partner, and MV deformation.

CONCLUSION

User safety errors (not using a seatbelt, seatbelt misuse, excessive seat-back reclining, and insecure cargo) and a lack of occupant protection in older MVs resulted in young adults sustaining severe or fatal injuries in MVCs.

Prevalence and concentrations of sedative-hypnotic drugs in blood of drivers involved in road traffic crashes in the Padova region of Italy - not so easy to interpret

BACKGROUND & OBJECTIVES

This study reports the prevalence and concentrations of sedative-hypnotic drugs as exemplified by benzodiazepines (BZD) and zolpidem (Z-hypnotic) in blood samples from drivers involved in road traffic accidents (RTA) in the Padova region of Italy. Another aim of the study was to estimate the prevalence of these drugs with concentrations in blood above the therapeutic intervals and above specific per se limits.

METHODS

A total of 4066 blood samples collected from drivers involved in RTA were analysed for the presence of alcohol, drugs of abuse and medicinal drugs with sedative-hypnotic properties. Prevalence of drivers positive for BZDs and zolpidem were reported according to the reporting limit of our laboratory (1 ng/mL) in a sort of zero tolerance approach and compared with the prevalence according to analytical cut-offs used in the "European Union's research project on Driving Under the Influence of Drugs, Alcohol and Medicines" (DRUID). The impairment-based, per se limits adopted in Norway and in England and Wales and the values used to define "therapeutic ranges" in blood and in plasma/serum were also applied to the case study.

RESULTS

175 blood samples were positive for sedative-hypnotics above 1 ng/mL, with the following prevalence: diazepam 44%, nordazepam 41.8%, lorazepam 32.6%, zolpidem 28%, oxazepam 25.6%, alprazolam 16%, delorazepam 11,6%, lormetazepam 11,6%, temazepam 11.6%, clonazepam 11.6%, triazolam 6.9%, N-desalkylflurazepam 4.6%, bromazepam 2.3%. When applying DRUID analytical cut-offs, the prevalence of BZDs and zolpidem sharply decreases. Applying the impairing cut-offs used in Norway, 56% of positive samples were above the limits equivalent to a BAC of 0.2 g/L, 39% above the limits corresponding to 0.5 g/L, and 23% above the cut-off corresponding to 1.2 g/L. Only 1% of the drivers had drug concentrations above the per se concentration limits adopted in England and Wales [26]. When comparing blood levels with therapeutic ranges in plasma, bromazepam, lormetazepam and delorazepam were often found above the highest limits. The adjustment of the concentrations with the plasma-to-blood ratios causes a significant increase of cases above the therapeutic ranges in plasma.

CONCLUSIONS

Sedative-hypnotic drugs are medicinal substances frequently identified in drivers involved in RTA, commonly in concentrations associated with driving impairment. Besides the concentrations of drugs in blood, several factors have to be considered to conclude that a driver was impaired. The frequent association with alcohol, cocaine and other BZDs, confirms the abuse potential of these medications.

Severe Neurological Sequelae after a Recreational Dose of LSD

A young man with an unremarkable medical history suffered a seizure with subsequent cardiorespiratory arrest and severe neurological sequelae after ingesting a blotter. Analysis of a similar blotter and a serum sample obtained 3 h after the event detected lysergic acid diethylamide (LSD) at an amount of 300 µg in the blotter and at a concentration of 4.0 ng/mL (12.4 nmol/L) in the serum. No other drugs were present in concentrations which may confer significant effects. In addition, no individual traits which would make the patient particularly susceptible to adverse LSD effects have subsequently been identified. This suggests that LSD may confer toxic effects in previously healthy individuals.

Alcohol and drug consumption among motor vehicle drivers in the Brittany region of France: A 9-year cross-sectional population study

The primary objective of the present study was to evaluate the frequency of positive tests for alcohol and drugs during roadside testing or after road accidents among drivers in the Brittany region of France. The study’s secondary objective was to describe the blood concentrations of the substances found during these tests, in order to provide a scientific basis for the establishment or modification of legislative threshold values for road injuries prevention. We performed a cross-sectional study of a database compiled by Rennes University Hospital’s toxicology laboratory in the Brittany region of France between 2010 and 2018. Driver’s age, sex, and test status (positive or negative), and blood levels of ethanol, 9-tetrahydrocannabinol (THC), methylene dioxymethamphetamine (MDMA), amphetamine, benzoylecgonine and 6-monoacetylmorphine (6-MAM) were collected. Twelve thousand four hundred and ninety-seven drivers (males: 86.1%; median (range) age: 29 (15–94)) have provided roadside blood samples, giving a total of 25,998 test results. Among the 10,996 drivers with at least one positive test, the median blood concentrations of ethanol, THC, MDMA, amphetamine, benzoylecgonine, and 6-MAM were respectively 1.82 g/L, 2.41 ng/mL, 138.4 ng/mL, 67.7 ng/mL, 173.3 ng/mL, and 0.97 ng/mL. 1159 (10.54%) of the 10,996 drivers tested positive for two or more substances, and 151 (1.4%) tested positive for three or more substances. With the exception of heroin, the currently recommended threshold values appear to be appropriate for road injuries prevention with regard to the concentrations observed in offenders.

Alcohol and drug use among road users involved in fatal crashes in Norway

OBJECTIVE

To study the prevalence of alcohol and drugs in biological samples from drivers, motorcycle riders, bicyclists, and pedestrians involved in fatal road traffic crashes (RTCs) during 2016-2018 in Norway, both among fatally injured victims and those who survived fatal RTCs.

METHODS

Anonymous information was extracted from police data. No personal data were recorded.

RESULTS

There were 330 fatal RTCs with 349 killed road users and 384 survivors during the study period; this included 179 passengers who were excluded from the study. In total, 90% of the studied killed road users and 67% of the survivors were investigated for alcohol or drug use by analyzing biological samples. Alcohol or drugs in concentrations above the legal limits were detected in 21% of the analyzed samples. The proportion impaired by alcohol or drugs (blood alcohol concentrations equal to or greater than 0.05%, or drug concentrations above equivalent limits) was highest among killed bicyclists (43%), higher than among killed pedestrians (24%), car and van drivers (28%) and motorcyclists (20%), and significantly higher than among drivers who survived fatal crashes (4%).

CONCLUSIONS

Impairment due to use of alcohol or drugs was often a contributing factor among bicyclists, pedestrians and motor vehicle drivers who died in RTCs. Driving under the influence of alcohol or drugs was more often a contributing factor in cases where the motor vehicle driver was killed than in cases where the driver survived.

Cannabis, Impaired Driving, and Road Safety: An Overview of Key Questions and Issues

The road safety impact of cannabis has been a topic of much discussion and debate over the years. These discussions have been revitalized in recent years by initiatives in several jurisdictions to legalize non-medical cannabis. Canada became the second country to legalize non-medical cannabis use in October, 2018, preceded by Uruguay in December 2013. Road safety concerns were key issues in the Canadian government's deliberations on the issue. In this paper, we identify several key questions related to the impact of cannabis on road safety, and provide a consideration of the relevant literature on these questions. These questions cover several perspectives. From an epidemiological perspective, perhaps the central question is whether cannabis use contributes to the chances of being involved in a collision. The answer to this question has evolved in recent years as the ability to conduct the relevant studies has evolved. A related question is the extent to which cannabis plays an important role in road safety, and recent research has made progress in estimating the collisions, injuries, and deaths that may be attributed to cannabis use. Several questions relate to the behavioral and pharmacological effects of cannabis. One central question is whether cannabis affects driving skills in ways that can increase the chances of being involved in a collision. Another important question is whether the effects of the drug on the driving behavior of medical users is similar to, or different from, the effects on non-medical users and whether there are sex differences in the pharmacological and behavioral effects of cannabis. Other important questions are the impact of tolerance to the effects of cannabis on road safety as well as different routes of administration (e.g., edibles, vaped). It remains unclear if there is a dose-response relationship of cannabis to changes in driving. These and other key questions and issues are identified and discussed in this paper.

"Residual blood THC levels in frequent cannabis users after over four hours of abstinence: A systematic review."

BACKGROUND

Tetrahydrocannabinol (THC), the primary psychoactive component of cannabis, causes psychomotor impairment and puts drivers at increased risk of motor vehicle collisions. Many jurisdictions have per se limits for THC, often 2 or 5 ng/mL, that make it illegal to drive with THC above the "legal limit". People who use cannabis regularly develop partial tolerance to some of its impairing effects. Regular cannabis users may also have persistent elevation of THC even after a period of abstinence. Some stakeholders worry that current per se limits may criminalize unimpaired drivers simply because they use cannabis. We conducted a systematic review of published literature to investigate residual blood THC concentrations in frequent cannabis users after a period of abstinence.

METHODS

We identified relevant articles by combining terms for "cannabis" and "blood" and "concentration" and "abstinence" and searching MEDLINE, EMBASE, PsycINFO, and Web of Science. We included studies that reported THC levels in frequent cannabis users after more than 4 h of abstinence.

RESULTS

Our search identified 1612 articles of which 8 met our inclusion criteria. After accounting for duplicate publications, we had identified 6 independent studies. These studies show that blood THC over 2 ng/mL does do not necessarily indicate recent cannabis use in frequent cannabis users. Five studies reported blood THC >2 ng/mL (or plasma THC >3 ng/mL) in some participants after six days of abstinence and two reported participants with blood THC >5 ng/mL (or plasma THC > 7.5 ng/mL) after a day of abstinence.

CONCLUSIONS

Blood THC >2 ng/mL, and possibly even THC >5 ng/mL, does not necessarily represent recent use of cannabis in frequent cannabis users.

Determination of the alcohol biomarker phosphatidylethanol 16:0/18:1 and 33 compounds from eight different drug classes in whole blood by LC-MS/MS

INTRODUCTION

Most bioanalytical LC-MS/MS methods are developed for determination of single drugs or classes of drugs, but a multi-compound LC-MS/MS method that can replace several methods could reduce both analysis time and costs. The aim of this study was to develop a high-throughput LC-MS/MS method for determination of the alcohol biomarker phosphatidylethanol 16:0/18:1 (PEth 16:0/18:1) and 33 other compounds from eight different drug classes in whole blood.

METHODS

Whole-blood samples were prepared by 96-well supported liquid extraction (SLE). Chromatographic separations were performed on a biphenyl core shell column with a mobile phase consisting of 10 mM ammonium formate, pH 3.1 and methanol. Each extract was analyzed twice by LC-MS/MS, injecting 0.4 μL and 2 μL, in order to obtain narrow and symmetrical peaks and good sensitivity for all compounds. Stable isotope-labeled internal standards were used for 31 of the 34 compounds.

RESULTS

A 96-well SLE reversed phase LC-MS/MS method for determination of PEth 16:0/18:1 and 33 other compounds from eight different drug classes was developed and validated. By using an organic solvent mixture of isopropanol/ methyl tert-butyl ether (1:5, v:v), all compounds, including the polar and ampholytic compounds pregabalin, gabapentin and benzoylecgonine, was extracted by 96-well SLE.

DISCUSSION/CONCLUSION

For the first time an LC-MS/MS method for the determination of alcohol biomarker PEth 16:0/18:1 and drugs and metabolites from several different drug classes was developed and validated. The developed LC-MS/MS method can be used for high-throughput analyses and sensitive determinations of the 34 compounds in whole blood.

Rate of elimination of γ-hydroxybutyrate from blood determined by analysis of two consecutive samples from apprehended drivers in Norway

AIM

Gamma-hydroxybutyrate (GHB) is a common drug of abuse with an elimination half-life of 20-45 min. However, there is some evidence that GHB might exhibit saturation kinetics after ingesting high recreational doses. The aim of this study was to investigate the elimination kinetics of GHB from blood in people apprehended by the police for impaired driving and secondary to describe concentrations in all GHB-positive drivers.

METHODS

Two consecutive blood samples were taken about 30-40 min apart from N = 16 apprehended drivers in Norway. GHB was determined in blood by an Ultra High-Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS) method. The changes in GHB between the two consecutive blood samples allowed estimating GHB's elimination half-life, assuming first-order and zero-order elimination kinetics. GHB concentrations are also reported for N = 1276 apprehended drivers with GHB in blood.

RESULTS

The median time interval between collecting the two blood samples was 36 min (range 20-56 min). The median concentration of GHB in the first blood sample was 56.5 mg/L (range 14.1-142 mg/L) compared with 47.8 mg/L in the second sample (range 9.75-113 mg/L). The median elimination half-life was 103 min (range 21-187 min), and GHB's median zero-order elimination rate constant was 21.0 mg/L/h (range 6.71-45.4 mg/L/h). Back-calculation to the time of driving resulted in GHB concentrations up to 820 mg/L assuming first-order kinetics and up to 242 mg/L assuming zero-order kinetics. In all drivers (N = 1276), the median GHB concentration was 73.7 mg/L and highest was 484 mg/L.

CONCLUSION

The elimination half-life of GHB in blood samples from apprehended drivers was longer than expected compared with results of controlled dosing studies. Zero-order kinetics seems a more appropriate model for GHB when concentrations are back-calculated, and the median elimination rate was 21 mg/L/h.

Do dried blood spots (DBS) have the potential to support result management processes in routine sports drug testing?

Dried blood spots (DBS) have been considered as complementary matrix in sports drug testing for many years. Especially concerning substances prohibited in-competition only, the added value of DBS collected concomitantly with routine doping control urine samples has been debated, and an increasing potential of DBS has been discussed in the scientific literature. To which extent and under which prerequisites DBS can contribute to enhanced anti-doping efforts is currently evaluated. As a proof-of-principle, two analytical applications, one targeting cocaine/benzoyl ecgonine and the other prednisone/prednisolone, are presented in this perspective to indicate potential added value but also presently existing limitations of the DBS approach.

The implementation of per-se limits for driving under the influence of benzodiazepines and related drugs: No increased risk for arrest during therapeutic use in Norway

Objective: To investigate whether the use of recommended therapeutic doses of medicinal drugs has led to suspicion of driving under the influence of drugs (DUID) after implementation of legislative limits for illicit and medicinal drugs in 2012.Methods: Data from suspected drug-impaired drivers apprehended by the police from 2013 to 2015 were selected from the Norwegian Forensic Toxicology Database. The blood samples had been analyzed for benzodiazepines (BZDs), z-hypnotics, opioids, stimulants, certain hallucinogens, and alcohol. Drivers who tested positive for one BZD or a z-hypnotic only, were included in the study. Drug concentrations measured in their blood samples were compared to the maximal obtainable steady state concentrations if the drug had been used in accordance with the recommendations set by the Norwegian Directorate of Health.Results: BZDs or z-hypnotics were found in 10 248 samples, representing 59.6% of the total number of drivers arrested for suspected DUID (n = 17 201). Only one BZD or z-hypnotic with a blood drug concentration above the legislative limit was detected in 390 (2.3%) of the total number of samples. Clonazepam was the most frequently detected BZD (n = 4656), while as a single drug above the legislative limit, it was detected in only 3.6% (n = 168) of the clonazepam-positive blood samples. For drivers testing positive for only one z-hypnotic, drug concentrations above the legislative limit were found in 27% (n = 55) of the blood samples that tested positive for zolpidem and 12.4% (n = 53) of the samples that tested positive for zopiclone. In total, 155 subjects out of 10 248 testing positive for BZDs or z-hypnotics displayed concentrations above the legislative limit but within the concentration ranges that are expected when taking recommended therapeutic drug doses, and 77 below the legislativel limit.Conclusions: The results show that the implementation of legislative limits for BZDs and z-hypnotics may have contributed to DUID suspicion for a small group of patients using therapeutic drug doses; only 1.3% of the suspected DUID offenders had concentrations of only one of those drugs in-line with recommended therapeutic dosing.

THC-influenced drivers in the new Danish 3-level offense system

Objective: The objectives of the study were to describe the distribution of tetrahydrocannabinol (THC)-influenced drivers in a new Danish 3-level offense system and discuss the consequences of the changed legislation.Methods: By request of the police, blood of individuals suspected of driving under the influence of drugs (DUID) in Funen and Southern Jutland was sampled by medical staff and shipped to the Section of Forensic Toxicology of the University of Southern Denmark in Odense. Samples from individuals suspected for driving under the influence of cannabis (DUIC) were stored at 5 °C prior to immediate analysis, and THC content in whole-blood samples was established by gas chromatography-mass spectrometry analysis. Quantitative results for blood THC levels were available from 2017 and 2018, resulting in 2,206 eligible cases. Data before and after the legal change on December 15, 2017, were extracted from the department's laboratory information management system.Results: With the new graduated sanctions introduced in December 2017, 70% of the DUIC suspects faced milder sanctions. The number of DUIC cases has been increasing and has almost doubled in the last 4 years, from 648 cases in 2015 to 1,206 in 2018. Correspondingly, the total number of DUID cases increased by 80% from 898 cases in 2015 to 1,614 cases in 2018. The concentration of THC in blood was above the legal limit of 0.001 mg/kg in 73% of the cases; 18% had concentrations categorized as low, 32% as medium, and 22% as high.Conclusion: We found that more than two-thirds of the THC offenders faced milder sanctions compared to before the new legislation, suggesting that the new graduated legislation has had a significant impact. The current trend is a steadily increasing number of DUID cases. We believe that the continual increase is caused by a combination of factors, including increased police awareness and training of police personnel along with improved roadside screening abilities.

Driver-related risk factors of fatal road traffic crashes associated with alcohol or drug impairment

Fatal road traffic crashes are often related to speeding, non-use of a seatbelt, and alcohol/drug-impaired driving. The aim of this study was to examine associations between driving under the influence of drugs and/or alcohol and driver-related risk factors that have been reported as significantly contributing causes of fatal road traffic crashes. The data were extracted from Norwegian road traffic crash registries and forensic toxicology databases. Drug/alcohol investigated car and van drivers and motorcycle riders fatally injured in road traffic crashes in Norway during 2005-2015 were included in this study (n = 772). Drug and alcohol concentrations corresponding to 0.5 g/kg alcohol in blood were used as the lower limits for categorising drivers/riders as impaired; 0.2 g/kg was the upper limit for being categorised as sober. Associations between driver-related risk factors and impairment from specific substance groups were calculated using multivariable logistic regression, adjusted for other substance groups, age, and sex, and were reported when the confidence intervals did not contain the value 1 or lower. Substances found in concentrations above the impairment limits were mainly alcohol (20%), medicinal drugs (10%: benzodiazepines, opioids, z-hypnotics), stimulants (5%: amphetamines, methylphenidate, and cocaine), and cannabis (4%: THC). The drug/alcohol-impaired drivers had compared to the sober drivers more often been speeding (68% versus 32%), not used a seatbelt (69% versus 30%), and been driving without a valid driver license (26% versus 1%). Logistic regression analysis showed that impairment from alcohol or stimulants (mainly amphetamines) was associated with all three risk factors, medicinal drugs with all except speeding, and impairment from cannabis (THC) with not having a valid driver license. Among motorcycle riders, drug/alcohol impairment was associated with not having a valid driver license and non-use of a helmet. At least one of the risk factors speeding, non-use of a seatbelt/helmet, and driving without a valid license were present among the vast majority of the drug/alcohol-impaired fatally injured drivers and riders, and also among more than half of the fatally injured sober drivers.

Cannabis use as a risk factor for causing motor vehicle crashes: a prospective study

AIM

We conducted a responsibility analysis to determine whether drivers injured in motor vehicle collisions who test positive for Δ-9-tetrahydrocannabinol (THC) or other drugs are more likely to have contributed to the crash than those who test negative.

DESIGN

Prospective case-control study.

SETTING

Trauma centres in British Columbia, Canada.

PARTICIPANTS

Injured drivers who required blood tests for clinical purposes following a motor vehicle collision.

MEASUREMENTS

Excess whole blood remaining after clinical use was obtained and broad-spectrum toxicology testing performed. The analysis quantified alcohol and THC and gave semiquantitative levels of other impairing drugs and medications. Police crash reports were analysed to determine which drivers contributed to the crash (responsible) and which were 'innocently involved' (non-responsible). We used unconditional logistic regression to determine the likelihood (odds ratio: OR) of crash responsibility in drivers with 0 < THC < 2 ng/ml, 2 ng/ml ≤ THC < 5 ng/ml and THC ≥ 5 ng/ml (all versus THC = 0 ng/ml). Risk estimates were adjusted for age, sex and presence of other impairing substances.

FINDINGS

We obtained toxicology results on 3005 injured drivers and police reports on 2318. Alcohol was detected in 14.4% of drivers, THC in 8.3%, other drugs in 8.9% and sedating medications in 19.8%. There was no increased risk of crash responsibility in drivers with THC < 2 ng/ml or 2 ≤ THC < 5 ng/ml. In drivers with THC ≥ 5 ng/ml, the adjusted OR was 1.74 [95% confidence interval (CI) = 0.59-6.36; P = 0.35]. There was significantly increased risk of crash responsibility in drivers with blood alcohol concentration (BAC) ≥ 0.08% (OR = 6.00;95% CI = 3.87-9.75; P < 0.01), other recreational drugs detected (OR = 1.82;95% CI = 1.21-2.80; P < 0.01) or sedating medications detected (OR = 1.45; 95%CI = 1.11-1.91; P < 0.01).

CONCLUSIONS

In this sample of non-fatally injured motor vehicle drivers in British Columbia, Canada, there was no evidence of increased crash risk in drivers with Δ-9-tetrahydrocannabinol < 5 ng/ml and a statistically non-significant increased risk of crash responsibility (odds ratio = 1.74) in drivers with Δ-9-tetrahydrocannabinol ≥ 5 ng/ml.

Prevalence of therapeutic drugs in blood of drivers involved in traffic crashes in the area of Bologna, Italy

INTRODUCTION

Psychoactive medicines, such as benzodiazepines and Z-drugs (BdZ), antidepressants and antipsychotics (AA) and medical opioids (MO), have an impairing effect on driving ability. In previous epidemiological studies performed on impaired and/or injured drivers, not all relevant psychoactive substances were included in the toxicological assessment, and their prevalence may be underestimated. This study aims to assess the prevalence of a large set of psychoactive substances (n=53) in Italian drivers involved in a road traffic crash and in predefined population subgroups.

MATERIALS AND METHODS

The toxicological analyses were performed on the whole blood of 1026 drivers involved in a road traffic crash in the area of Bologna, Italy, from January 2017 to March 2018. Analyses were performed using GC-FID (alcohol), GCMS (illicit drugs) and LC/HRMS (psychoactive drugs). The population was divided into subgroups according to gender, age and crash time. Descriptive statistics were used in order to assess differences among sub-groups.

RESULTS

The highest prevalence was found for alcohol (17.3%), followed by medicinal drugs (13.6%) and illicit drugs (5.5%). The prevalence of BdZ, AA and MO were 7.3%, 7.2% and 3.1%, respectively. The frequency of BDZ and AA was significantly higher in female drivers and showed higher prevalence at increasing age. The presence of medicinal drugs was significantly higher during the week and in crashes occurring during the day.

CONCLUSION

Results for alcohol and illicit drugs partially overlap with those reported in previous European and Italian studies, but the prevalence of BdZ was much higher. We also found a high prevalence of AA, which are rarely investigated in epidemiological studies performed on drivers, but may cause impairment of the ability to drive, especially when taken in combination with alcohol or other drugs. The pattern of medication use differs from that involving drugs of abuse, since it is mainly observed in female subjects and older drivers and does not follow the same weekly trend observed for alcohol and other illicit drugs.

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.

Association between speeding and use of alcohol and medicinal and illegal drugs and involvement in road traffic crashes among motor vehicle drivers

OBJECTIVE

The objective of this study was to study the association between self-reported road traffic crashes (RTCs) and recent use of alcohol and medicinal and illicit drug use and self-reported speeding in the previous 2 years.

METHODS

During the period from April 2016 to April 2017, drivers of cars, vans, motorcycles, and mopeds were stopped in a Norwegian roadside survey performed in collaboration with the police. Participation was voluntary and anonymous. The drivers were asked to deliver an oral fluid sample (mixed saliva), which was analyzed for alcohol and 39 illicit and medicinal drugs and metabolites. In addition, data on age, sex, and self-reported speeding tickets and RTCs during the previous 2 years were collected.

RESULTS

A total of 5,031 participants were included in the study, and 4.9% tested positive for the use of one or more illicit or medicinal drugs or alcohol. We found a significant, positive association between the use of cannabis and RTC involvement (odds ratio [OR] = 1.93; 95% confidence interval [CI], 1.05-3.57; P = 0.035) and also between previous speeding tickets and RTC involvement (OR = 1.39; 95% CI, 1.08-1.80; P = 0.012). In addition, older age groups were found to have a significant, negative association with RTC involvement, with ORs equal to or less than 0.49, when using the age group 16-24 as reference.

CONCLUSION

Speeding, as an indicator of risk behavior, and the use of cannabis were associated with previous RTC involvement, whereas increasing age was significantly associated with lower risk. This is consistent with previous studies on RTCs.

Driving under the influence of drugs: Prevalence in road traffic accidents in Italy and considerations on per se limits legislation

OBJECTIVE

The objective of this study was to present the prevalence and concentrations of drugs in blood samples of drivers involved in road traffic accidents (RTAs) and to discuss the effects of adopting different concentration cutoff values proposed or applied in other European countries on the number of driving under the influence of drugs (DUID) offenses.

METHODS

Blood samples from drivers involved in RTAs in Padova province from 2014 to 2017 were analyzed for the presence of alcohol and drugs. The prevalence of positive subjects was reported for each substance adopting the limits of quantification (LOQs) of our laboratory and the concentration cutoff values proposed and/or used in other European countries. The reduction of cases of driving under the influence of illicit drugs in applying different cutoffs was calculated.

RESULTS

Four thousand four hundred forty-three blood samples were analyzed: 23.7% were positive for alcohol and 19.9% for psychoactive drugs, with prevalences of polydrug and alcohol-drug abuse of 4.5 and 6%, respectively. The most frequently detected drugs were cannabinoids (9.7%) and cocaine (7.2%), followed by benzodiazepines (4.1%), opiates (1.9%), and other opioids (1.7%). Barbiturates, amphetamines, and ketamine were identified in a much smaller number of cases. The overall decrease in DUID cases when adopting different cutoffs with respect to cases above the LOQs was between 8 and 84%. The adoption of high LOQs such as those used in the European Union's research project on Driving Under the Influence of Drugs, Alcohol and Medicines (DRUID) decreases the hypothetical number of DUID offenses by a quarter, and per se limits proposed as broadly equivalent to a blood alcohol concentration (BAC) between 0.2 and 0.8 g/L dramatically reduce the cases of DUID (cocaine -81%, cannabis -79%, opioids -97%, opiates -96%, and amphetamines -77%); no ketamine-positive samples were above the cutoff.

CONCLUSIONS

The implementation of high analytical limits or per se limits based on impairing concentrations in the Italian legislation could result in the prosecution of a much lower number of drugged drivers involved in RTAs, with a decrease from 25% to more than 80% depending on the limits.

Association between alcohol and drug use and arrest for driving under the influence after crash involvement in a rural area of Norway: a case-control study

OBJECTIVES

The rate of deaths caused by road traffic crashes is particularly high in rural areas. It has been hypothesised that one factor that may contribute is differences in patterns of alcohol use. The aim was to compare the prevalence of psychoactive substances among crash-involved drivers arrested for suspicion of driving under the influence (DUI) who are tested for alcohol and drugs and recent random drivers in a rural area. Furthermore, we investigated the association between traffic crashes and driving after using alcohol, illicit or medicinal drugs either alone or in combination.

METHODS

A case-control study was carried out in which the case group consisted of crash-involved drivers arrested for suspicion of DUI from 2000 to 2015. This group was compared with a control group of randomly selected drivers recruited to a roadside survey in normal traffic from 2014 to 2015. The case group consisted of 612 individuals (542 men and 70 women) and the control group of 3027 individuals (2099 men and 927 women). Drug and alcohol screening was performed on blood samples from the cases and samples of oral fluid from the controls.

RESULTS

The proportion of psychoactive substances was 81.7% among cases and 1.6% among the controls. The prevalence of combinations of psychoactive substances was 18% among the cases and 0.3% among the controls. The multivariate regression model analysis identified significant drug interactions.

CONCLUSION

The prevalence of alcohol and drugs was high among the crash-involved drivers arrested for suspicion of DUI by the police. In contrast to earlier published research combinations of different psychoactive substances did not increase the OR for traffic crash involvement more than the single drug with highest OR. The statistical methodology presented in this study should be allied in future studies with greater statistical power to confirm these findings.

Roadside survey of alcohol and drug use among Norwegian drivers in 2016-2017: A follow-up of the 2008-2009 survey

OBJECTIVE

The objective of this study was to study the use of alcohol and drugs among the general driving population in the southeastern part of Norway and to compare the findings with the results from a similar roadside survey in 2008-2009.

METHODS

A roadside survey of drivers of cars, vans, motorcycles, and mopeds was performed from April 2016 to April 2017 in collaboration with the Mobile Police Service. Oral fluid was collected using the Quantisal device and analyzed for alcohol, illicit drugs, and psychoactive medicinal drugs. Age, sex, time, and geographical region were recorded.

RESULTS

Of the 5,556 drivers who were asked to participate in the study, 518 drivers (9.3%) declined to participate, and 4 samples contained insufficient volume of oral fluid to be analyzed; thus, 5,034 drivers were included. Fifteen drivers (0.3%) suspected by the police for driving under the influence of alcohol or drugs refused to participate in the study, so the alcohol and drug findings represent minimum values. The weighted prevalence of alcohol concentrations above the legal limit of 0.2 g/L was 0.2%, which is similar to the finding in the 2008-2009 survey. The weighted prevalences of medicinal drugs and illicit drugs were 3.0 and 1.7%, respectively; those numbers included more drugs than the 2008-2009 survey and are therefore not comparable. The most prevalent illicit and medicinal drugs were tetrahydrocannabinol (1.3%) and zopiclone (1.4%). The prevalences of benzodiazepines and amphetamines were significantly lower than detected in the 2008-2009 survey. Only one sample tested positive for a new psychoactive substance.

CONCLUSIONS

The proportion of samples that tested positive for alcohol had not changed since 2008-2009, and the proportions that tested positive for benzodiazepines and amphetamines were lower. There are several possible reasons for the reduction: Implementation of legal limits for 28 drugs in 2012-2016, increased use of drug recognition tests, implementation of drug screening instruments, and automatic number plate recognition by the police since 2010; more focused enforcement of the driving under the influence (DUI) law; better information provided to drivers; and changes in drug prescriptions.

Police documentation of drug use in injured drivers: Implications for monitoring and preventing drug-impaired driving

INTRODUCTION

Most countries have laws against driving while impaired by drugs. However, in many countries, including Canada and the United States, police must have individualized suspicion that the driver has recently used an impairing substance before they can gather the evidence required for laying a criminal charge. This report studies police documentation of drug involvement among drivers who had a motor-vehicle crash after using an impairing substance.

METHODS

We obtained blood samples and police reports on injured drivers treated in participating British Columbia trauma centres following a crash. Blood was analyzed for alcohol, cannabinoids, other recreational drugs, and impairing medications. Corresponding police reports were examined to determine whether police recorded that the driver's ability was impaired by alcohol, drug or medication, or that one of these substances was a possible contributory factor in the crash.

RESULTS

We obtained blood samples and corresponding police reports on 1816 injured drivers. Mean driver age was 44 years, 63.2% were male, and 25.8% were admitted to hospital. Alcohol was detected in 272 drivers (15.0%), THC (tetrahydrocannabinol - the principal psychoactive ingredient in cannabis) in 136 (7.5%), other recreational drugs in 166 (9.1%), and potentially impairing medications in 363 (20.0%). Police reported that the driver's ability was impaired by alcohol or that alcohol was a possible contributory factor in 64.1% of the crashes involving alcohol-positive drivers. Drug impairment or drugs as a possible contributory factor was reported in 5.9% of the crashes involving THC-positive drivers, and in 16.9% of the crashes involving drivers who tested positive for other recreational drugs. Medication impairment was reported in only 2.2% of the crashes involving medication-positive drivers.

CONCLUSION

Police seldom document drug involvement in drivers who were in a crash after using cannabis, other recreational drugs or potentially impairing medications. This finding raises serious concerns about the ability of the police to effectively enforce current drug-impaired driving laws and public health officials' continued reliance on police crash reports to monitor the prevalence of drug-impaired driving.

The acute and residual effects of escalating, analgesic-range doses of ketamine on driving performance: A simulator study

Ketamine hydrochloride elicits potent psychotomimetic and neurobehavioural effects which make it incompatible with driving; however, the direct effect on driving performance is yet to be assessed. Using an open label, within-subjects protocol, 15 males and 5 females (mean age = 30.8 years) were administered three fixed, stepwise increasing sub-anaesthetic doses of intravenous (IV) ketamine solution [(i) 8 mg/h IV infusion plus 30 mg bolus, (ii) 12 mg/h IV infusion and (iii) 20 mg/h infusion]. Whole blood ketamine and norketamine concentrations were determined at each treatment step and at 2 h post-infusion. Driving performance was assessed at baseline, at each treatment step and at 2 h post-treatment using a validated computerised driving simulator. Standard Deviation of Lateral Position (SDLP) and Steering Variability (SV) were assessed. Linear Fixed Effect Modelling indicated a main effect for time (dose) for SDLP (F_[4,72] = 33.22, p < 0.0001) and SV (F_[4,72] = 4.65, p < 0.002). Post-hoc analyses revealed significant differences from baseline at each treatment step for SDLP (all p < 0.001), and for 12 mg/h treatment step for SV (p = 0.049). Post-treatment driving performance returned to baseline levels. Weak positive linear associations were observed between SDLP and whole blood ketamine concentrations (R² = 0.11, β = 29.96, p = 0.001) and norketamine (R² = 0.09, β = 28.87, p = 0.003). These findings suggest that even under highly controlled conditions, ketamine intoxication significantly alters simulated driving performance. At the highest dose, ketamine produced changes to SDLP considered incompatible with safe driving, highlighting how ketamine consumption may translate to an increased risk of road trauma.

Driving under the influence of alcohol and drugs in the eastern part of Denmark in 2015 and 2016: Abuse patterns and trends

OBJECTIVES

The objective of this study was to examine the frequency of psychoactive drugs and alcohol in drivers under suspicion of driving under the influence of drugs and alcohol in 2015 and 2016 in the eastern part of Denmark. The trends in the number of traffic cases sent for drug analysis since 2000 and alcohol analysis since 2011 are also discussed.

METHODS

Blood samples from drivers suspected of being under the influence of alcohol and/or medication and/or illicit drugs in 2015 and 2016 were investigated as requested by the police. The blood samples were screened for alcohol and/or tetrahydrocannabinol (THC) alone, for other drugs (covering all drugs, except THC, listed in the Danish list of narcotic drugs), or for THC and other drugs. Age and gender were also recorded. The number of drug traffic cases since 2000 and the number of alcohol cases since 2011 were extracted from our Laboratory Information Management System (LIMS).

RESULTS

In total, 11,493 traffic cases were investigated. Alcohol and/or drugs exceeded the legal limit in 9,657 (84%) cases. Men constituted 95% of the drivers investigated for drugs and 88% of the alcohol cases. The drivers investigated for drugs consisted primarily of young men, whereas drivers investigated for alcohol were older. The frequency was higher for positive alcohol cases above the legal limit (87%) than for drug cases (76%) above the fixed concentration limit. THC (67-69%) was the most frequently detected drug above the legal limit, followed by cocaine (27-28.5%), amphetamine (17%), and clonazepam (6-7%) in both years. Morphine (5.4%), included among the 5 most frequent drugs in 2015, was replaced by methadone (4.6%) in 2016. Few new psychoactive drugs (NPS) were detected. The number of traffic cases sent for drug analysis has increased more than 30-fold since 2000-2006, and the number of traffic cases submitted in 2016 for drug analysis was higher than the number for alcohol analysis; the latter has decreased since 2011.

CONCLUSION

Overall, alcohol was the most frequent compound detected above the legal limit in both years, followed by the well-known illicit drugs THC, cocaine, and amphetamine. NPS were seldom seen. One consequence of the increased focus on drugs in traffic has been an immense increase in drug traffic cases sent for analysis since 2006 in the eastern part of Denmark. Although this survey revealed only minimal changes compared to earlier investigations, surveys like this are invaluable for monitoring abuse patterns and trends in drugged and drunken driving.

In silico (computed) modelling of doses and dosing regimens associated with morphine levels above international legal driving limits

BACKGROUND

Morphine can cause central nervous system side effects which impair driving skills. The legal blood morphine concentration limit for driving is 20 µg/L in France/Poland/Netherlands and 80 µg/L in England/Wales. There is no guidance as to the morphine dose leading to this concentration.

AIM

The in silico (computed) relationship of oral morphine dose and plasma concentration was modelled to provide dose estimates for a morphine plasma concentration above 20 and 80 µg/L in different patient groups.

DESIGN

A dose-concentration model for different genders, ages and oral morphine formulations, validated against clinical pharmacokinetic data, was generated using Simcyp^®, a population-based pharmacokinetic simulator.

SETTING/PARTICIPANTS

Healthy Northern European population parameters were used with age, gender and renal function being varied in the different simulation groups. In total, 36,000 simulated human subjects (100 per modelled group of different ages and gender) received repeated simulated morphine dosing with modified-release or immediate-release formulations.

RESULTS

Older age, women, modified-release formulation and worse renal function were associated with higher plasma concentrations. Across all groups, morphine doses below 20 mg/day were unlikely to result in a morphine plasma concentration above 20 µg/L; this was 80 mg/day with the 80 µg/L limit.

CONCLUSION

This novel study provides predictions of the in silico (computed) dose-concentration relationship for international application. Individualised morphine prescribing decisions by clinicians must be informed by clinical judgement considering the individual patient's level of impairment and insight irrespective of the blood morphine concentration as people who have impaired driving will be breaking the law. Taking into account expected morphine concentrations enables improved individualised decision making.

Determination of 12 commonly found compounds in DUID cases in whole blood using fully automated supported liquid extraction and UHPLC-MS/MS

A high-throughput UHPLC-MS/MS method for the most frequently found compounds; tetrahydrocannabinol (THC), amphetamine, methamphetamine, MDMA, clonazepam, diazepam, nordiazepam, oxazepam, alprazolam, nitrazepam, morphine, and codeine, in driving under the influence of drugs (DUID) cases in whole blood, is presented. Automated sample preparation by 96-well supported liquid extraction (SLE) plates with ethyl acetate + heptane (80 + 20, v/v) as organic solvent was carried out on a Freedom Evo 200 platform from Tecan. An aliquot of 100 μL whole blood was used. Sample preparation time for 96 samples was 1.5 h. Compounds were separated with gradient elution on a C₁₈ column (50 × 2.1 mm, 1.7 μm) with a mobile phase consisting of 5 mM pH 10.2 ammonium formate and methanol. The run time was 4.5 min and 1 μL was injected on an Acquity UPLC I-Class system with a Xevo TQS tandem-quadrupole mass spectrometer in multiple-reaction monitoring mode (MRM) from Waters. Isotope labelled, ¹³C, internal standards (ISs) were used for all compounds except for alprazolam and morphine, which had deuterated analogs. Quantification was carried out with calibrators without whole blood matrix. Full validation was carried out according to international guidelines, and a new approach for evaluation of process efficiency (PE) has been presented. Linear or quadratic weighted (1/x) calibration curves were used with R² ≥ 0.999. The method showed satisfactory deviations ±16% when compared to the existing methods, and satisfactory agreement with proficiency testing control samples (z-score -1.6 to 1.8, n = 16 samples). The precision, estimated as the relative standard deviation (RSD) of the concentration difference between results from two independent analyses of authentic whole blood samples, was ≤7.2% in antemortem and ≤9.3% in postmortem samples. Recovery was ≥85% for all the compounds, except morphine ≥62% and THC ≥ 50%. PE was satisfactory for all the compounds with low variation in IS response, RSD ≤ 16% (THC 27%) in antemortem samples and ≤34% (THC 66%) in postmortem samples. To the best of our knowledge, this is the first automated 96-well SLE UHPLC-MS/MS method developed for the simultaneous determination of these 12 compounds in whole blood covering the concentration ranges found in forensic samples. The method has been used in routine work during the last ten months, analysing about 9900 antemortem and 1000 postmortem whole blood samples, and has proven to be robust and reliable.

The significance of preexisting medical conditions, alcohol/drug use and suicidal behavior for drivers in fatal motor vehicle crashes: a retrospective autopsy study

Driver fatalities in motor vehicle collisions (MVCs) encompass accidents, suicides, and natural deaths when driving. The objective of this study was to determine the significance of pathology and other autopsy findings for drivers in fatal MVCs. Forensic autopsy records of driver fatalities in southeast Norway between 2000 and 2014 were studied retrospectively. Data from individual police and collision investigation reports were also collected and analyzed. In 406 driver fatalities, the male/female ratio was 340/66; 9% died from natural causes, 9% were suicides, 65% were culpable accidental deaths, 14% were nonculpable deaths, and 3% were undetermined deaths. Head injuries and thoracic injuries were the most common causes of death. A seatbelt had been worn in 50% of the fatalities, and its prevalence did not differ between accidental deaths and suicides. Blood levels of alcohol and/or drugs that indicated impairment at the time of the collision were found in 40% (105/262) of all culpable accidental deaths but in 50% (64/127) of drivers aged up to 35 years. Pathology (most often cardiovascular disease) suggestive of sudden incapacitation before the collision was present in 24% (62/264) of drivers who were culpable in the accident and in 70% (46/66) of culpable drivers older than 55 years. A substantial proportion of drivers are killed in accidental collisions that may have occurred as a result of either alcohol/drug impairment or preexisting disease. Suicides and natural deaths both constitute significant proportions of MVC fatalities and may be misclassified unless a full inquest including an autopsy is performed.

Increasing use of cannabis among arrested drivers in Norway

OBJECTIVE

The availability of cannabis in Norway seems to have increased according to seizures by customs and police. On the other hand, national population surveys have not found any increase in self-reported use of cannabis. This investigation aimed at studying trends in cannabis use among suspected drug-impaired drivers apprehended by the police in Norway.

METHODS

A time series observational study of cannabis use among all drivers tested for drugs during 2000-2015 was performed. Descriptive analyses of trends in frequencies and combined use of cannabis with other drugs or alcohol for different age groups and gender were conducted.

RESULTS

Tetrahydrocannabinol (THC) is the main psychoactive substance in cannabis and was detected in blood samples from 18,767 suspected drug-impaired drivers. The annual number of THC findings increased during the years 2000-2015 for all age groups. For cannabis-only users, young drivers aged 20-29 years dominated during the whole period, whereas for multidrug-cannabis users the median age increased steadily during 2000-2015. After 2009, the annual increase in THC findings escalated; THC-only findings increased the most.

CONCLUSIONS

Increasing numbers of THC-positive drivers were found among all age groups and genders; the strongest trend was observed between 2009-2015 for young drivers testing positive only for THC.

Conversion factors for assessment of driving impairment after exposure to multiple benzodiazepines/z-hypnotics or opioids

AIMS

Norway has introduced legal concentration limits in blood for 28 non-alcohol drugs in driving under the influence cases. As of 2016 this legislation also regulates the assessment of combined effects of multiple benzodiazepines and opioids. We herein describe the employed methodology for the equivalence tables for concentrations of benzodiazepines/z-hypnotics and opioids implemented in the Norwegian Road Traffic Act.

METHODS

Legislative limits corresponding to impairment at blood alcohol concentrations (BAC) of 0.02%, 0.05% and 0.12% were established for 15 different benzodiazepines and opioids. This was based on a concept of a linear relationship between blood drug concentration and impairment in drug naïve users. Concentration ratios between these drugs were used to establish conversion factors and calculate net impairment using diazepam and morphine equivalents.

RESULTS

Conversion factors were established for 14 benzodiazepines/z-hypnotics (alprazolam, bromazepam, clobazam, clonazepam, etizolam, flunitrazepam, lorazepam, nitrazepam, nordiazepam, oxazepam, phenazepam, temazepam, zolpidem and zopiclone) and two opioids (methadone and oxycodone).

CONCLUSIONS

Conversion factors to calculate diazepam and morphine equivalents for benzodiazepines/z-hypnotics and selected opioids, respectively, have been operative in the Norwegian Road Traffic Act as of February 2016. Calculated equivalents can be applied by the courts to meter out sanctions.

Driving under the influence of drugs: Perceptions and attitudes of New Zealand drivers

This study explored the patterns of drug driving in New Zealand by investigating 1) drivers' perceptions about impairment caused by legal and illegal drugs 2) countermeasures employed by drivers when under the influence of drugs (e.g., decisions not to drive) 3) drivers' attitudes about police enforcement of drug driving and 4) the factors that predict the likelihood of engaging in drug driving. Participants (n=434) were licensed drivers who completed an online questionnaire. Results of the questionnaire indicated that drivers rated hallucinogens and opiates as being the illegal drugs producing the highest level of driving impairment and cannabis the lowest. For legal drugs, sedatives were rated as having the highest driving impairment and anti-nausea and anti-depressants the lowest. Respondents' drug use history had an effect on their ratings of impairment for anti-anxiety drugs, anti-depressants, kava, sedatives, cannabis and hallucinogens such that drug users reported higher impairment ratings than Non-user. Making a decision not to drive after taking drugs was reported by users of alcohol (73.6%), cannabis (57.0%), strong painkillers (42.5%), and anti-depressants (10.0%). Respondents who reported drink driving were 3.26 times more likely to report drug driving than those reporting no drink driving. Respondents also showed greater acceptance towards driving under the influence of legal drugs (43.5%) compared to illegal drugs (10.3%). Those who did not have favourable attitudes about drug driving were less likely to report having driven under the influence of drugs. Drivers in this sample were less aware of the potential negative effects of legal drugs on driving compared to illegal drugs. More than half the respondents from this study acknowledged drug driving as a road safety issue which needs more resources dedicated to it.

The Effects of Acute Cannabis Use on Nontraffic Injury Risk: Reviewing the Available Literature and Identifying Ways Forward

Recent evidence has indicated that cannabis use before driving is associated with a modest but increased risk for traffic-related injuries. However, the question of whether recent cannabis use is associated with a greater risk for other types of injuries remains unanswered. Aiming to understand better how acute cannabis use might affect the risk for all causes of injury, we have summarized the limited data available in the literature on the risk of non-traffic injuries associated with recent cannabis use. Very few studies were able to provide estimate risks for all injuries or injuries other than those related to road traffic injuries, with the limited evidence available showing mixed findings. The only significant risk found (in only one study) suggests an inverse association between all injuries and cannabis use. Study designs are limited, and the majority of studies have neither data on acute cannabis use among injured individuals nor a valid control group for estimating injury risk attributable to cannabis. In conclusion, studies of the association between cannabis and non-traffic injuries present several limitations, particularly regarding sampling strategies, injury risk assessment for different causes of injury, and a dose-response risk relationship with injury. Further studies, incorporating better design for different causes of injury and drug testing, are required to reach firmer conclusions on the association between cannabis use and non-traffic injury risk.

Lower-Risk Cannabis Use Guidelines: A Comprehensive Update of Evidence and Recommendations

BACKGROUND

Cannabis use is common in North America, especially among young people, and is associated with a risk of various acute and chronic adverse health outcomes. Cannabis control regimes are evolving, for example toward a national legalization policy in Canada, with the aim to improve public health, and thus require evidence-based interventions. As cannabis-related health outcomes may be influenced by behaviors that are modifiable by the user, evidence-based Lower-Risk Cannabis Use Guidelines (LRCUG)-akin to similar guidelines in other health fields-offer a valuable, targeted prevention tool to improve public health outcomes.

OBJECTIVES

To systematically review, update, and quality-grade evidence on behavioral factors determining adverse health outcomes from cannabis that may be modifiable by the user, and translate this evidence into revised LRCUG as a public health intervention tool based on an expert consensus process.

SEARCH METHODS

We used pertinent medical search terms and structured search strategies, to search MEDLINE, EMBASE, PsycINFO, Cochrane Library databases, and reference lists primarily for systematic reviews and meta-analyses, and additional evidence on modifiable risk factors for adverse health outcomes from cannabis use.

SELECTION CRITERIA

We included studies if they focused on potentially modifiable behavior-based factors for risks or harms for health from cannabis use, and excluded studies if cannabis use was assessed for therapeutic purposes.

DATA COLLECTION AND ANALYSIS

We screened the titles and abstracts of all studies identified by the search strategy and assessed the full texts of all potentially eligible studies for inclusion; 2 of the authors independently extracted the data of all studies included in this review. We created Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow-charts for each of the topical searches. Subsequently, we summarized the evidence by behavioral factor topic, quality-graded it by following standard (Grading of Recommendations Assessment, Development, and Evaluation; GRADE) criteria, and translated it into the LRCUG recommendations by the author expert collective on the basis of an iterative consensus process.

MAIN RESULTS

For most recommendations, there was at least "substantial" (i.e., good-quality) evidence. We developed 10 major recommendations for lower-risk use: (1) the most effective way to avoid cannabis use-related health risks is abstinence, (2) avoid early age initiation of cannabis use (i.e., definitively before the age of 16 years), (3) choose low-potency tetrahydrocannabinol (THC) or balanced THC-to-cannabidiol (CBD)-ratio cannabis products, (4) abstain from using synthetic cannabinoids, (5) avoid combusted cannabis inhalation and give preference to nonsmoking use methods, (6) avoid deep or other risky inhalation practices, (7) avoid high-frequency (e.g., daily or near-daily) cannabis use, (8) abstain from cannabis-impaired driving, (9) populations at higher risk for cannabis use-related health problems should avoid use altogether, and (10) avoid combining previously mentioned risk behaviors (e.g., early initiation and high-frequency use).

AUTHORS' CONCLUSIONS

Evidence indicates that a substantial extent of the risk of adverse health outcomes from cannabis use may be reduced by informed behavioral choices among users. The evidence-based LRCUG serve as a population-level education and intervention tool to inform such user choices toward improved public health outcomes. However, the LRCUG ought to be systematically communicated and supported by key regulation measures (e.g., cannabis product labeling, content regulation) to be effective. All of these measures are concretely possible under emerging legalization regimes, and should be actively implemented by regulatory authorities. The population-level impact of the LRCUG toward reducing cannabis use-related health risks should be evaluated. Public health implications. Cannabis control regimes are evolving, including legalization in North America, with uncertain impacts on public health. Evidence-based LRCUG offer a potentially valuable population-level tool to reduce the risk of adverse health outcomes from cannabis use among (especially young) users in legalization contexts, and hence to contribute to improved public health outcomes.

Impairment due to alcohol, tetrahydrocannabinol, and benzodiazepines in impaired drivers compared to experimental studies

OBJECTIVE

In some countries, per se laws for other drugs than alcohol are used to judge drunk and drugged drivers. These blood concentration limits are often derived from experimental studies on traffic relevant behavior of healthy volunteers. Knowledge about how results from experimental studies could be transferred to a real-life setting is missing. The aim of this study was to compare impairment seen in experimental studies to the impairment seen at equivalent concentrations in apprehended drunk and drugged drivers.

METHODS

Results from previously performed meta-analyses of experimental studies regarding impairment from alcohol, tetrahydrocannabinol (THC), and benzodiazepines were compared to impairment in apprehended drunk and drugged drivers as judged by a clinical test of impairment. Both experimental studies and real-life cases were divided into 4 groups according to increasing blood drug concentration intervals. The percentage of impaired test results in experimental studies was compared to the percentage of impaired subjects among drivers within the same blood drug concentration window.

RESULTS

For ethanol, the percentage of impaired drivers (n = 1,223) increased from 59% in the lowest drug concentration group to 95% in the highest drug concentration group, compared to 7 and 72% in the respective groups in experimental studies. For THC, the percentage of impaired drivers (n = 950) increased from 42 to 58%, the corresponding numbers being 11 and 42% for experimental studies. For benzodiazepines, the percentage of impaired drivers (n = 245) increased from 46 to 76%, the corresponding numbers being 16 and 60% for experimental studies. The increased odds ratio for impairment between 2 concentration groups was comparable for experimental studies and impaired drivers.

CONCLUSIONS

Fewer test results indicated impairment in experimental studies compared to impaired drivers in real life when influenced by similar blood concentrations of either ethanol, THC, or benzodiazepines. In addition, a comparable relationship between drug concentration and impairment was seen for both experimental studies and real-life cases. We believe that the present study strengthens the background for using experimental studies to establish fixed concentration limits for drunk and drugged drivers, but experimental studies in an impaired driver population could further expand our knowledge.

Prevalence and concentrations of drugs in older suspected drugged drivers

OBJECTIVE

Older drivers are somewhat more likely to be involved in car crashes than middle-aged drivers but less likely to be involved than younger drivers. This study aimed to assess the extent of drug use in older suspected drunk and drugged drivers, with respect to which drugs were detected and at which concentrations.

METHODS

Blood samples from older suspected drunk and drugged drivers taken between February 1, 2012, and May 22, 2013, were identified from the database at the Norwegian Institute of Public Health and were retrospectively analyzed for a broad repertoire of drugs relevant for impairment. The prevalence of different drugs among the suspected drunk and drugged drivers was studied. Regarding drug concentrations, the findings in older drivers (>65 years) were compared to a reference group of apprehended drivers aged 20-40 years.

RESULTS

Four hundred and ten older suspected drunk and drugged drivers were included. Any drug (including ethanol) was detected in 92% of blood samples, and ethanol was detected in 81%. Benzodiazepines were found in 15% of the older drivers and z-hypnotics (zopiclone or zolpidem) were detected in 13%. The most frequent single legal drugs found in blood samples taken from older impaired drivers were zopiclone (9.8%) and diazepam (9.3%). Regarding drug combinations, older drivers used a mean number of 1.4 drugs, and 20% of ethanol-positive cases showed at least one other drug. High drug concentrations of clonazepam and diazepam were more frequently seen in the younger group.

CONCLUSIONS

This study showed that drugs were detected in the vast majority of older drivers suspected for drunk or drugged driving. Ethanol was the most frequent drug detected, followed by zopiclone and diazepam. Older drivers combine drugs to a lesser degree than younger drivers, but their combination of ethanol and other drugs represents a considerable traffic risk. Lower concentrations of benzodiazepines are seen in older compared to younger drivers.