Toxicological findings in suspected drug-impaired drivers in Norway — Trends during 1990–2015

Do crashed drivers need more drug testing? A retrospective analysis of blood samples from hospitalised post-crash drivers in New Zealand

Driving under the influence of alcohol and other drugs is a prominent safety concern in New Zealand and across the world. While alcohol testing is routinely performed for drivers involved in hospitalisation crashes, testing for other drugs is often not undertaken. The present study refers to 530 traffic crashes that occurred from October 2019 to January 2020 on New Zealand roads. The blood samples from 550 drivers who were injured in a crash and were admitted to a hospital (66% of all drivers involved in these crashes), previously tested for drugs and/or alcohol, were retested for a wider range of drugs. Alcohol above the applicable limit was found to be present in 38% of hospitalised drivers, while other drugs of interest were found in 47% of hospitalised drivers. Binary logistic regression was used to predict the presence of drugs of interest for a crashed driver using previous offence data. A driver having at least one prior drink and drug driving offence is 61% more likely to be positive for a drug of interest when involved in a crash. Similarly, a driver having at least one prior non-traffic drug offence is 4.7 times more likely to be positive for at least a drug of interest when involved in a crash. While the presence of a drug or drugs cannot be presumed to have played a role in the occurrence of the crash, this study has provided a unique and comprehensive picture of the presence of various drugs present in New Zealand drivers' blood. It is recommended to consider standardising drug testing on all blood specimens taken in relation to a serious injury or fatal crash. This procedure is not only of interest for information purposes but may importantly inform appropriate charging decisions.

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.

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.

Comparative Study of Postmortem Concentrations of Benzodiazepines and Z-Hypnotics in Several Different Matrices

Benzodiazepines and z-hypnotics are detected in the majority of fatal overdose cases in Norway, often in combination with other drugs of abuse, and their concentrations in peripheral blood (PB) might be important to elucidate the cause of death. In some forensic autopsies, PB is however not available. The aim of the present study was to compare concentrations of benzodiazepines and z-hypnotics in five alternative matrices to assess whether these concentrations are comparable to concentrations in PB. A total of 109 forensic autopsy cases were included. PB, cardiac blood (CB), pericardial fluid (PF), psoas muscle (PM), lateral vastus muscle (LVM) and vitreous humor (VH) from each case were analyzed using ultra high performance liquid chromatography--tandem mass spectrometry. We were able to detect clonazepam, 7-aminoclonazepam, flunitrazepam, 7-aminoflunitrazepam, nitrazepam, 7-aminonitrazepam, diazepam, nordiazepam, oxazepam, alprazolam, midazolam, zopiclone and zolpidem in all the analyzed matrices. Concentrations measured in VH were generally much lower than those of PB for all compounds except zopiclone. 7-Amino metabolite concentrations were high compared to the parent compounds, although less so for the muscle samples. Concentrations of the parent nitrobenzodiazepines in muscles were higher than those in PB, but for the other compounds, concentrations in muscle showed good correspondence with PB. Both CB and PF were viable alternative matrices for PB, although a larger variation and a tendency for higher concentrations in PF were observed. This study shows that CB, PM, LVM and PF can give comparable concentrations to PB for benzodiazepines and z-hypnotics, while VH was less suitable. The concentrations in alternative matrices must, however, be interpreted carefully.

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.

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.

A New Strategy for Efficient Retrospective Data Analyses for Designer Benzodiazepines in Large LC-HRMS Datasets

The expanding and dynamic market of new psychoactive substances (NPSs) poses challenges for laboratories worldwide. The retrospective data analysis (RDA) of previously analyzed samples for new targets can be used to investigate analytes missed in the first data analysis. However, RDA has historically been unsuitable for routine evaluation because reprocessing and reevaluating large numbers of forensic samples are highly work- and time-consuming. In this project, we developed an efficient and scalable retrospective data analysis workflow that can easily be tailored and optimized for groups of NPSs. The objectives of the study were to establish a retrospective data analysis workflow for benzodiazepines in whole blood samples and apply it on previously analyzed driving-under-the-influence-of-drugs (DUID) cases. The RDA workflow was based on a training set of hits in ultrahigh-performance liquid chromatography–quadrupole time-of-flight–mass spectrometry (UHPLC-QTOF-MS) data files, corresponding to common benzodiazepines that also had been analyzed with a complementary UHPLC–tandem mass spectrometry (MS/MS) method. Quantitative results in the training set were used as the true condition to evaluate whether a hit in the UHPLC-QTOF-MS data file was true or false positive. The training set was used to evaluate and set filters. The RDA was used to extract information from 47 DBZDs in 13,514 UHPLC-QTOF-MS data files from DUID cases analyzed from 2014 to 2020, with filters on the retention time window, count level, and mass error. Sixteen designer and uncommon benzodiazepines (DBZDs) were detected, where 47 identifications had been confirmed by using complementary methods when the case was open (confirmed positive finding), and 43 targets were not reported when the case was open (tentative positive finding). The most common tentative and confirmed findings were etizolam (n = 26), phenazepam (n = 13), lorazepam (n = 9), and flualprazolam (n = 8). This method efficiently found DBZDs in previously acquired UHPLC-QTOF-MS data files, with only nine false-positive hits. When the standard of an emerging DBZD becomes available, all previously acquired DUID data files can be screened in less than 1 min. Being able to perform a fast and accurate retrospective data analysis across previously acquired data files is a major technological advancement in monitoring NPS abuse.

A systematic review of factors associated with illegal drug driving

Drug driving is a serious problem worldwide that can increase the risk of road crashes. This systematic review seeks to identify factors associated with drug driving (i.e., driving after consuming drugs other than alcohol) to highlight gaps in existing knowledge and inform the design of more effective countermeasures. A search of the literature was conducted for the period January 1, 2005 to July 31, 2021 using six different databases. The search protocol followed PRISMA guidelines and was registered in PROSPERO (#CRD42021234616). Studies that met inclusion criteria compared drug drivers with either non-drug drivers, alcohol-only drivers or drug drivers from an earlier time period, to identify factors specifically associated with drug driving, rather than common to all drivers. Two hundred and nineteen publications met the inclusion criteria and were included within the review. Based on the findings, a logic model was developed that presents the factors associated with drug driving. Various sociodemographic, psychosocial and legal factors emerged as the main factors associated with illegal drug driving. At the sociodemographic and psychological levels, drug drivers were more likely to be single, young males who often drive after using cannabis and who score high on sensation-seeking and impulsivity scales. The key social factor found to be associated with drug driving was peer acceptance/disapproval of the behaviour. At the legal level, the review suggested that the effectiveness of current enforcement approaches to drug driving vary among jurisdictions around the world due to differences in the level of perceived certainty of apprehension and the chances of punishment avoidance. Future research into the anticipated and actual rewards for drug driving is needed to inform the development of more effective countermeasures.

Differences in the risk profiles of drunk and drug drivers: Evidence from a mandatory roadside survey

BACKGROUND

The study assesses the prevalence rates of alcohol- and drug-involved driving in Catalonia (Spain).

METHOD

Drivers were randomly selected for roadside testing using a stratified random sampling procedure representative of all vehicles circulating on non-urban roads. Mandatory alcohol and drug tests were performed during autumn 2017. A sample of 6860 drivers were tested for alcohol use, of these 671 were also tested for drugs. Standard procedures were employed by traffic officers to detect alcohol and drug use. Alcohol breath tests were performed with breathalyser devices and on-site drug screening systems were used to test for drugs.

RESULTS

The prevalence of alcohol use above the legal limit and drug use were 1.2 % (95 % CI: 0.9-1.5 %) and 8.3 % (95 % CI: 5.8-11.2 %), respectively. The most frequent drugs detected were THC (5.6 %, 95 % CI: 3.7-8.0 %), cocaine (3.5 %, 95 % CI: 2.0-5.5 %) and amphetamines (1.6 %, 95 % CI: 0.6-3.4 %). Alcohol use was detected more frequently on conventional roads, at weekends and during night-time hours. Drug use was detected more frequently in young males during daytime hours.

CONCLUSIONS

Driver risk profiles associated with alcohol use and drug use differ. Positive alcohol use is not a predictor of drug use when controlling for all other factors.

Interpol review of toxicology 2016-2019

This review paper covers the forensic-relevant literature in toxicology from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20.Papers%202019.pdf.

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.

Alcohol and illicit drugs in drivers involved in road traffic crashes in Italy. An 8-year retrospective study

This study aims to investigate the prevalence of alcohol and drugs of abuse in Italian drivers involved in road traffic crashes between 2011 and 2018. Toxicological analyses were performed on the whole blood of 7593 injured drivers. Alcohol and illicit drugs, namely tetrahydrocannabinol (THC; cut-off 2ng/ml), cocaine (cut-off 10ng/ml), illicit opiates (cut-off 10ng/ml) and amphetamines (amphetamine, methamphetamine, MDMA, MDA; cut-off 20ng/ml) were investigated. The age and gender of the driver, the time of the crash (weekend/weekday and day/night), the road crash year and Blood Alcohol Concentration (BAC) were also considered. The 16.2% of samples tested positive for alcohol, 2.5% for cocaine, followed by opiates (2.0%), cannabinoids (1.5%), and amphetamines (0.5%). The overall prevalence of alcohol and drugs was lower than those reported in previous epidemiological studies of the DRUID project. The year 2011 showed the highest prevalence of drug-positive cases (24.1%), while the lowest prevalence was found in 2016 (16.8%), after the update of the Road Traffic Law (RTL) that increased punishments for driving under the influence. A progressive increase in the number of alcohol-positive female drivers was observed from 2011 to 2018, and the highest prevalence was found in the 26-35-year-old age range. Illicit drugs showed the highest overall prevalence in drivers <26 years of age but, if considering single drugs, cocaine and opiates were mostly found in subjects older than 36 years of age. A higher percentage of drug-positive drivers was found on weekend nights for alcohol and on both weekend and weekday nights for drugs. The types of drugs used by drivers did not change during the studied period.

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.

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.

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.

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.

Prevalence of drug use among drivers based on mandatory, random tests in a roadside survey

Background

In the context of road safety, this study aims to examine the prevalence of drug use in a random sample of drivers.

Methods

A stratified probabilistic sample was designed to represent vehicles circulating on non-urban roads. Random drug tests were performed during autumn 2014 on 521 drivers in Catalonia (Spain). Participation was mandatory. The prevalence of drug driving for cannabis, methamphetamines, amphetamines, cocaine, opiates and benzodiazepines was assessed.

Results

The overall prevalence of drug use is 16.4% (95% CI: 13.9; 18.9) and affects primarily younger male drivers. Drug use is similarly prevalent during weekdays and on weekends, but increases with the number of occupants. The likelihood of being positive for methamphetamines is significantly higher for drivers of vans and lorries.

Conclusions

Different patterns of use are detected depending on the drug considered. Preventive drug tests should not only be conducted on weekends and at night-time, and need to be reinforced for drivers of commercial vehicles. Active educational campaigns should focus on the youngest age-group of male drivers.