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

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.

International approaches to driving under the influence of cannabis: A review of evidence on impact

BACKGROUND

There are knowledge gaps regarding the effectiveness of different approaches designed to prevent and deter driving under the influence of cannabis (DUIC). Policymakers are increasingly interested in evidence-based responses to DUIC as numerous jurisdictions worldwide have legally regulated cannabis or are debating such regulation. We contribute a comprehensive review of international literature on countermeasures that address DUIC, and identify where and how such measures have been evaluated.

METHODS

The following databases were systematically searched from 1995 to present: Medline, Embase, PsycINFO, CINAHL, Sociological Abstracts, and Criminal Justice Abstracts. Hand searching of relevant documents, internet searches for grey literature, and review of ongoing email alerts were conducted to capture any emerging literature and relevant trends.

RESULTS

Numerous international jurisdictions have introduced a variety of measures designed to deter DUIC. Much interest has been generated regarding non-zero per se laws that set fixed legal limits for tetrahydrocannabinol and/or its metabolites detected in drivers. Other approaches include behavioural impairment laws, zero-tolerance per se laws, roadside drug testing, graduated licensing system restrictions, and remedial programs. However, very few evaluations have appeared in the literature.

CONCLUSIONS

Although some promising results have been reported (e.g., roadside testing), it is premature to draw firm conclusions regarding the broader impacts of general deterrent approaches to DUIC. This review points to the need for a long-term commitment to rigorously evaluate, using multiple methods, the impact of general and specific deterrent DUIC countermeasures.

Influence of alcohol and other substances of abuse at the time of injury among patients in a Norwegian emergency department

BACKGROUND

The presence of alcohol or other substances of abuse in blood or urine from injured patients is often used as a proxy for substance influence at the time of injury. The aim of this study was to obtain an estimate of substance influence at the time of injury based on blood concentrations of alcohol and other substances of abuse, and to explore the relationship between the substance prevalence at the time of admittance to the hospital and the actual influence at the time of the injury.

METHODS

The study included all adult patients admitted to the emergency department of a university hospital during 1 year (n = 996). Quantification in blood was done by an enzymatic method for alcohol, and by liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry for 28 other substances of abuse. Concentrations of alcohol and other substances in blood at the time of injury were calculated. The degree of influence was assessed on the basis of the calculated blood concentrations, with a threshold of influence set at a blood alcohol concentration (BAC) of 0.05 %, or a substance concentration leading to an influence similar to that of a BAC of 0.05 %.

RESULTS

A total of 324 patients (32.5 %) were determined to be under the influence at the time of injury. In comparison, 394 patients (39.6 %) had one or more substances above the cut-off limit in blood at the time of admittance to the hospital. Alcohol was the most prevalent substance causing influence at 25.9 %. Among patients with violence-related injuries, almost 75 % were under the influence of alcohol and/or substances. Patients under the influence were younger, and men were more often under the influence than women. More patients were under the influence at nighttime and during weekends than at daytime and on weekdays.

CONCLUSIONS

About one third of the injured patients were determined to be under the influence at the time of injury, with alcohol being the most prevalent substance causing influence. Approximately 98 % of the patients with alcohol detected in blood at the time of admittance to the hospital were under the influence of alcohol at the time of injury.

Prevalence of alcohol and drug use in injured British Columbia drivers

OBJECTIVES

Determine the prevalence of drug use in injured drivers and identify associated demographic factors and crash characteristics.

DESIGN

Prospective cross-sectional study.

SETTING

Seven trauma centres in British Columbia, Canada (2010-2012).

PARTICIPANTS

Automobile drivers who had blood obtained within 6 h of a crash.

MAIN OUTCOME MEASURES

We analysed blood for cannabis, alcohol and other impairing drugs using liquid chromatography/mass spectrometry (LCMS).

RESULTS

1097 drivers met inclusion criteria. 60% were aged 20-50 years, 63.2% were male and 29.0% were admitted to hospital. We found alcohol in 17.8% (15.6% to 20.1%) of drivers. Cannabis was the second most common recreational drug: cannabis metabolites were present in 12.6% (10.7% to 14.7%) of drivers and we detected Δ-9-tetrahydrocannabinol (Δ-9-THC) in 7.3% (5.9% to 9.0%), indicating recent use. Males and drivers aged under 30 years were most likely to use cannabis. We detected cocaine in 2.8% (2.0% to 4.0%) of drivers and amphetamines in 1.2% (0.7% to 2.0%). We also found medications including benzodiazepines (4.0% (2.9% to 5.3%)), antidepressants (6.5% (5.2% to 8.1%)) and diphenhydramine (4.7% (3.5% to 6.2%)). Drivers aged over 50 years and those requiring hospital admission were most likely to have used medications. Overall, 40.1% (37.2% to 43.0%) of drivers tested positive for alcohol or at least one impairing drug and 12.7% (10.7% to 14.7%) tested positive for more than one substance.

CONCLUSIONS

Alcohol, cannabis and a broad range of other impairing drugs are commonly detected in injured drivers. Alcohol is well known to cause crashes, but further research is needed to determine the impact of other drug use, including drug-alcohol and drug-drug combinations, on crash risk. In particular, more work is needed to understand the role of medications in causing crashes to guide driver education programmes and improve public safety.

Is toxicity of PMMA (paramethoxymethamphetamine) associated with cytochrome P450 pharmacogenetics?

In 2010-2013, 29 fatal intoxications related to the designer drug paramethoxymethamphetamine (PMMA, 4-methoxymethamphetamine) occurred in Norway. The current knowledge about metabolism and toxicity of PMMA in humans is limited. Metabolism by the polymorphic cytochrome P450 (CYP) 2D6 enzyme to the psychoactive metabolite 4-hydroxymethamphetamine (OH-MA), and possibly by additional enzymes, is suggested to be involved in its toxicity. The aim of this work was to study the association between CYP genetics, PMMA metabolism and risk of fatal PMMA toxicity in humans. The frequency distribution of clinically relevant gene variants of CYP2D6, CYP2C9, CYP2C19 and CYP3A5, and the phenotypic blood CYP2D6 metabolic ratio (OH-MA/PMMA) in particular, were compared in fatal PMMA intoxications (n=17) and nonfatal PMMA abuse controls (n=30), using non-abusers (n=305) as references for the expected genotype frequencies in the Norwegian population. Our study demonstrated that the CYP2D6 enzyme and genotype are important in the metabolism of PMMA to OH-MA in humans, but that other enzymes are also involved in this biotransformation. In the fatal PMMA intoxications, the blood concentrations of PMMA were higher and the CYP2D6 metabolic ratios were lower, than in the nonfatal PMMA abuse controls (median (range) 2.1 (0.03-5.0) vs 0.3 (0.1-0.9) mg/L, and ratio 0.6 (0.0-4.6) vs 2.1 (0.2-7.4) p=0.021, respectively). Overall, our findings indicated that, in most cases, PMMA death occurred rapidly and at an early stage of PMMA metabolism, following the ingestion of large and toxic PMMA doses. We could not identify any genetic CYP2D6, CYP2C9, CYP2C19 or CYP3A5 predictive marker on fatal toxicity of PMMA in humans. The overrepresentation of the CYP2D6 poor metabolizer (PM) genotype found in the nonfatal PMMA abuse controls warrants further investigations.

Determination of safety margins for whole blood concentrations of alcohol and nineteen drugs in driving under the influence cases

Legislative limits for driving under the influence of 20 non-alcohol drugs were introduced in Norway in February 2012. Per se limits corresponding to blood alcohol concentrations (BAC) of 0.2g/kg were established for 20 psychoactive drugs, and limits for graded sanctions corresponding to BACs of 0.5 and 1.2g/kg were determined for 13 of these drugs. This new legislation made it possible for the courts to make sentences based on the analytical results, similar to the situation for alcohol. To ensure that the reported concentration is as least as high as the true concentration, with a 99% safety level, safety margins had to be calculated for each of the substances. Diazepam, tetrahydrocannabinol (THC) and alcohol were used as model substances to establish a new model for estimating the safety margins. The model was compared with a previous used model established several years ago, by a similar yet much simpler model, and they were found to be in agreement. The measurement uncertainties depend on the standard batch used, the work list and the measurements' replicate. A Bayesian modelling approach was used to determine the parameters in the model, using a dataset of 4700 diazepam positive specimens and 5400 THC positive specimens. Different safety margins were considered for low and high concentration levels of diazepam (≤2μM (0.6mg/L) and >2μM) and THC (≤0.01μM (0.003mg/L) and >0.01μM). The safety margins were for diazepam 19.5% (≤2μM) and 34% (>2μM), for THC 19.5% (≤0.01μM) and 24.9% (>0.01μM). Concentration dependent safety margins for BAC were based on a dataset of 29500 alcohol positive specimens, and were in the range 10.4% (0.1g/kg) to 4.0% (4.0g/kg) at a 99% safety level. A simplified approach was used to establish safety margins for the compounds amphetamine, MDMA, methamphetamine, alprazolam, phenazepam, flunitrazepam, clonazepam, nitrazepam, oxazepam, buprenorphine, GHB, methadone, ketamine, cocaine, morphine, zolpidem and zopiclone. The safety margins for these drugs were in the range 34-41%.

Pharmacodynamic interactions of a solid formulation of sodium oxybate and ethanol in healthy volunteers

AIM

The pharmacologic effects of sodium oxybate (SO) have a number of similarities with those of alcohol. This study evaluated the pharmacodynamic interaction of SMO.IR (a solid immediate release formulation of SO) and alcohol (0.7 (males) or 0.57 (females) g kg(-1) alcohol using 40% vodka).

METHODS

In a randomized, double-blind, double-dummy, crossover trial, 24 healthy volunteers received randomly a) 2.25 g SMO.IR and placebo alcohol preparation, b) 2.25 g f SMO.IR and alcohol, c) 2.25 g SMO.IR matching placebo and alcohol and d) 2.25 g of SMO.IR matching placebo and placebo alcohol preparation. Objective and subjective cognitive parameters, adverse events and vital signs were assessed before, 15 and 165 min after treatment administration.

RESULTS

Alcohol produced the expected cognitive impairment and the expected subjective sedation rapidly after intake (from 15 min). The objective effects of SMO.IR were much less pronounced than those of alcohol. The reverse was observed for subjective complaints, which were related to lesser stimulation and greater sedation. Nevertheless, 165 min after administration this sedation feeling was less with SMO.IR than with alcohol. There was a significant interaction between SMO.IR and alcohol at 15 min (i.e. increase in alertness and stimulation and decrease in sedation). In addition, an isolated mild decrease in digit vigilance accuracy occurred at 165 min post-dose after the combination. The co-administration of SMO.IR and alcohol was safe and well-tolerated.

CONCLUSION

SMO.IR and alcohol have distinct adverse effect profiles. The objective effects of SMO.IR are much less marked than those of alcohol. No deleterious interaction was observed.

Prevalence of alcohol and drugs among motorcycle riders killed in road crashes in Norway during 2001-2010

The aim of the study was to examine the prevalence of alcohol and drugs in blood samples from motorcycle riders who died in road crashes in Norway from 2001 to 2010. An additional aim was to compare the prevalence of alcohol and drugs in blood samples from fatally injured motorcycle riders and car drivers who died during the same time period. Blood samples from motorcycle riders who died within 24h after the accident (n=207, 63% of all killed riders), were analysed for alcohol, psychoactive drugs (medicinal and illicit drugs). The cut-off concentrations for alcohol and drugs findings in blood samples (i.e., the drug concentrations above which a finding was regarded as positive) were set according to the legislative limits under the Norwegian Road Traffic Act. Results were assessed in relation to age, sex, time of the day and week, and single versus multiple-vehicle accidents. Alcohol or drugs were found in 27.1 percent of all investigated riders. For riders killed in single or multiple-vehicle accidents, alcohol or drugs were found in 44.6 and 15.3 percent, respectively. Alcohol was the most frequently found substance for all age groups and most prevalent in samples from riders below 25 years who died in single-vehicle accidents (45.8 percent). Drugs were most often found among riders between 25 and 34 years (19.6 percent in total and 25.9% for those killed in single-vehicle crashes). The prevalence of alcohol or drugs was highest among riders killed in single-vehicle accidents during weekend days and nights (60.9 and 65.2 percent). Alcohol and drugs were less often found in samples from killed motorcycles riders than in samples from car and van drivers (40.2 percent). For single-vehicle accidents, the total prevalence of alcohol or drugs among killed motorcycles riders and car drivers was 44.6 percent and 63.8 percent, respectively. The same pattern of alcohol and drugs was found among the two groups, except that the prevalence among motorcycle riders was lower compared to car drivers in all age groups and time periods, which may be related to the fact that they are more vulnerable for fatal injury compared to car drivers in similar accidents.

Associations between driving under the influence of alcohol or drugs, speeding and seatbelt use among fatally injured car drivers in Norway

Since 2005, all fatal road traffic crashes in Norway have been analyzed in-depth by multidisciplinary investigation teams organized by the Norwegian Public Roads Administration (NPRA). During the period 2005-2010, 608 drivers of cars or vans were killed in road traffic crashes. Blood samples were collected from 372 (61%) of the drivers and analyzed for alcohol and a large number of psychoactive drugs at the Norwegian Institute of Public Health (NIPH). After coupling the analytical results with the NPRA crash database, 369 drivers with a fatal outcome were identified and included. Alcohol or drug concentrations in blood above the legal limits were found in 39.8% of the drivers who were investigated for alcohol or drug impairment; 33.9% had blood alcohol concentrations above 0.5g/L or concentrations of drugs above the equivalent Norwegian legal impairment limits or concentrations of amphetamines above 200μg/L. Among drivers with a fatal outcome who had been impaired by alcohol or drugs, 64.6% were unbelted and 71.7% were speeding when the crash occurred; whereas 24.2% and 33.2% of the sober drivers were unbelted or speeding, respectively. Statistically significant associations were found between impairment by alcohol or amphetamines and driving unbelted or speeding. Excessive speeding is one of the main reasons for road traffic crashes and together with being unbelted the main reasons for a fatal outcome. This behavior might in many cases be due to increased risk-taking or negligence of safety measures as a result of alcohol or drug use.

Has Previous Abuse of Flunitrazepam Been Replaced by Clonazepam?

BACKGROUND AND AIMS

For many years, flunitrazepam was the benzodiazepine of choice among users of illegal drugs. The aim of this study was to investigate to which extent clonazepam use has increased in this population, and whether this was related to increased prescription or because of illegal availability.

METHODS

We used data from three sources to study the changes in the use of clonazepam: (1) Presence and concentrations of clonazepam and flunitrazepam in blood samples collected from Norwegian drugged drivers; (2) Sales numbers (legal market) for clonazepam, extracted from the Norwegian prescription database (NorPD), and (3) Specific seizures (illegal market) for clonazepam in Norway.

RESULTS

In 2004, 13.0% of the analysed blood samples from drugged drivers contained clonazepam, whereas this proportion had increased to 27.7% in 2013. In the same period, the frequency of flunitrazepam in drugged drivers decreased from 16.6% in 2004 to 3.2% in 2013. The number of clonazepam prescriptions decreased, while the number of seized tablets containing clonazepam increased considerably from 2004 to 2013.

CONCLUSIONS

For the last 10 years, a significant increase in the illegal use of clonazepam has been seen, now replacing flunitrazepam as the most used illegal benzodiazepine in Norway.

Impairment due to amphetamines and benzodiazepines, alone and in combination

INTRODUCTION

The impairing effects of combined use of amphetamines and benzodiazepines among recreational drug users are not well described, but knowledge about this is important in the risk assessment of such combined drug use. The aim of this study was to compare the impairment, among apprehended drivers, as judged by a clinical test of impairment (CTI), in cases where a combination of amphetamines and benzodiazepines was detected, in blood, with cases where only one of the two drug groups was detected.

METHODS

The results of CTI judgments were compared to toxicological drug tests of blood samples that were obtained at the time of CTI screening in cases containing amphetamines only, cases containing different benzodiazepines only, and cases containing a combination of amphetamines and benzodiazepines.

RESULTS

There were significantly more drivers being judged as impaired in the combined group (n = 777), compared both with amphetamines alone (n = 267, χ(2) = 47.8, p < 0.001) and benzodiazepines alone (n = 153, χ(2) = 7.0, p = 0.008). This was also seen when only including the lowest concentrations of benzodiazepines (χ(2) = 4.3, p = 0.038). The concentrations of the drugs were higher in the single drug groups, compared with the combined group.

CONCLUSION

This study indicates that during real-life driving, those influenced by both amphetamines and benzodiazepines are more impaired, as judged by the CTI, compared with those influenced by either drug alone, although the combined group showed lower drug concentrations.

The culpability of drivers killed in New Zealand road crashes and their use of alcohol and other drugs

Over a period of five years, blood samples were taken from 1046 drivers killed as a result of a motor vehicle crash on New Zealand roads. These were analysed for the presence of alcohol and a range of both illicit drugs and psychoactive medicinal drugs. Driver culpability was determined for all crashes. The control group of drug- and alcohol-free drivers comprised 52.2% of the study population. Drivers positive for psychoactive drugs were more likely to be culpable (odds ratio (OR) 3.5, confidence interval (CI) 95% 2.4-5.2) than the control group. Driver culpability exhibited the expected positive association with alcohol use (OR 13.7, 95% CI 4.3-44) and with combined alcohol and cannabis use (OR 6.9, 95% CI 3.0-16). There was only a weak positive association between cannabis use (with no other drug) and culpability (OR 1.3, CI 95% 0.8-2.3). Furthermore, the OR for drivers with blood tetrahydrocannabinol (THC) concentrations greater than 5 ng/mL was lower (OR 1.0, CI 95% 0.4-2.4) than drivers with blood THC concentrations less than 2 ng/mL (OR 3.1, CI 95% 0.9-10). This is inconsistent with results reported by other studies where a significant increase in crash risk was found with blood THC levels greater than 5 ng/mL. In this study, there were very few drivers who had used a single drug, other than cannabis or alcohol. Therefore, from this study, it is not possible to comment on any relationship between opioid, stimulant or sedative drug use and an increased risk of being killed in a crash for the drivers using these drugs. The results from a multivariate analysis indicate that driver gender, age group and licence status, (P=0.022, P=0.016, P=0.026, respectively), the type of vehicle being driven (P=0.013), the number of vehicles in the crash (P<0.001), the blood alcohol concentration of the driver (P<0.001) and the use of any drug other than alcohol and cannabis (P=0.044), are all independently associated with culpability.

Evaluation of ¹³C- and ²H-labeled internal standards for the determination of amphetamines in biological samples, by reversed-phase ultra-high performance liquid chromatography-tandem mass spectrometry

Stable isotope-labeled internal standards (SIL-ISs) are often used when applying liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze for legal and illegal drugs. ISs labeled with (13)C, (15)N, and (18)O are expected to behave more closely to their corresponding unlabeled analytes, compared with that of the more classically used (2)H-labeled ISs. This study has investigated the behavior of amphetamine, (2)H3-, (2)H5, (2)H6-, (2)H8-, (2)H11-, and (13)C6-labeled amphetamine, during sample preparation by liquid-liquid extraction and LC-MS/MS analyses. None or only minor differences in liquid-liquid extraction recoveries of amphetamine and the SIL-ISs were observed. The chromatographic resolution between amphetamine and the (2)H-labeled amphetamines increased with the number of (2)H-substitutes. For chromatographic studies we also included seven additional (13)C6-amphetamines and their analytes. All the (13)C6-labeled ISs were co-eluting with their analytes, both when a basic and when an acidic mobile phase were used. MS/MS analyses of amphetamine and its SIL-ISs showed that the ISs with the highest number of (2)H-substitutes required more energy for fragmentation in the collision cell compared with that of the ISs with a lower number. The findings, in this study, support those of previous studies, showing that (13)C-labeled ISs are superior to (2)H-labeled ISs, for analytical purposes.

Which drugs are associated with highest risk for being arrested for driving under the influence? A case-control study

The aim of this study was to determine the association between drug type and arrest for driving under the influence of drugs (DUID) by calculating odds ratios (ORs) using a case-control design. A DUID arrest is in most cases related to aberrant or risky driving and might therefore be regarded as a proxy for a drug related traffic crash. The 'cases' were 2738 drivers arrested on suspicion of drugged driving from April 2008 to March 2009 with blood alcohol concentrations below the legal limit of 0.2g/L; 794 were arrested due to involvement in road traffic crashes, whereas 1944 were arrested for other reasons, mainly dangerous driving, suspected impairment when stopped in traffic controls, or because of phone calls to the police from other road users or observers. The 'controls' were 9375 random drivers in normal traffic, also with alcohol concentrations below this limit. Blood samples from 'cases' and oral fluid samples from 'controls' were analyzed for 15 drugs that have legislative concentration limits in Norway, in addition to two other commonly detected psychoactive drugs. The most prevalent illicit drug in the control group was tetrahydrocannabinol (THC; 0.58%), which was also commonly found in samples from drivers arrested due to road crash (15.6%) or arrested for other reasons (21.8%). Amphetamine/methamphetamine was most prevalent among arrested drivers involved in crashes (30.6%) and drivers arrested for other reasons (56.9%), whereas only 0.18% of the control group was positive for amphetamine/methamphetamine. The single-use substances which gave highest OR for police arrest were amphetamine/methamphetamine, alprazolam, clonazepam and oxazepam. The majority of the alprazolam and clonazepam findings were probably due to non-therapeutic use of medicinal drugs purchased on the illegal market. Combinations of two or more drugs yielded higher ORs than the use of single substances; combinations of amphetamine/methamphetamine and benzodiazepines gave the highest risk.

Estimation of equivalent cutoff thresholds in blood and oral fluid for drug prevalence studies

Oral fluid is an easily available specimen for studying drug use in a cohort or population. The prevalence of drugs in samples of oral fluid is the same as the prevalence in blood if using equivalent cutoff concentrations. The cutoffs in oral fluid may be higher or lower than that in blood in accordance with the median oral fluid-to-blood (OF/B) concentration ratio, but it is also influenced by the skewness of the distribution of OF/B ratios. The aim of this study was to determine formulae for the estimation of equivalent cutoff concentrations in oral fluid and blood for 12 commonly used illegal and medicinal psychoactive drugs when oral fluid was collected with Statsure Saliva·Sampler™. Paired samples from 4,080 persons were collected and analyzed with chromatographic methods and mass spectroscopic detection. Regression formulae for the concentrations corresponding to selected percentiles in oral fluid versus the same concentration percentiles in blood were determined. The accuracy when multiplying the cutoff thresholds in blood with the average and median OF/B ratios to estimate equivalent cutoffs in oral fluid was also investigated. Prevalence regression gave the most accurate results. The regression formulae can be used to estimate equivalent cutoff concentrations in oral fluid and blood.

Prevalence of synthetic cannabinoids in blood samples from Norwegian drivers suspected of impaired driving during a seven weeks period

From early year 2000 different herbal products containing synthetic cannabinoids (SC) have appeared on the drug market all over the world, and new substances are frequently introduced. The prevalence of SC use in different populations is however still mainly unknown, also in Norway. This information is difficult to obtain, but studies of drivers suspected of driving under the influence of drugs (DUID), might provide important information. The aim of this study was to assess the prevalence of SC in drivers suspected of being under the influence of drugs in Norway, and investigate if SCs impair driving performance. For two periods of three and four weeks all blood samples from drivers suspected of DUID in Norway were analyzed for the presence of 12 and 18 different SCs, respectively. A new ultra performance liquid chromatography tandem mass spectrometry method was developed. A total of 726 cases were analyzed during our study period, and SCs were detected in 16 cases (2.2%) in total. The mean age of these drivers was 29.6 years. High concentrations of other psychoactive drugs were detected in all the blood samples where a SC was found. AM-2201 and JWH-018 were the most frequently detected SCs, each found in five cases. In addition RSC-4, JWH-122, JWH-081 and JWH-250 were detected. None of the drivers had reported using SCs prior to driving. Despite the limited number of SCs investigated in this 7 week study period, a considerable percent of the cases were positive. Other psychoactive drugs of abuse were always found concomitant with the SCs, and the age of these drivers indicates that experienced drug users also ingest SCs. Since other drugs were found in all the samples, the psychomotor impairment caused by the SCs is difficult to estimate. Our study shows the importance of screening analyses of biological samples from different populations to assess the prevalence of drug use, since self-reporting might be encumbered with significant under-reporting.

Prevalence of alcohol and drugs among car and van drivers killed in road accidents in Norway: an overview from 2001 to 2010

OBJECTIVES

To examine the prevalence of alcohol and drugs in blood samples collected from car and van drivers killed in traffic accidents in Norway during the time period from 2001 to 2010.

METHODS

Blood samples (n = 676, 63% of all killed drivers) were analyzed for alcohol, psychoactive medications, and illicit drugs. The cutoff limits for positive results were set according to the new legislative limits under the Norwegian Road Traffic Act. The results were assessed in relation to sex and age, time of day and day of week, and single- versus multiple-vehicle and all investigated vehicle accidents.

RESULTS

Alcohol or one or more drugs was detected in samples from 40.2 percent of all investigated drivers, with 28.7 percent showing blood concentrations of at least 5 times the legislative limits. For the investigated female drivers, the total prevalence was 24.0 percent. Among the single-vehicle accidents, alcohol or drugs was found in 63.8 percent of the cases, with 49.1 percent showing blood concentrations of at least 5 times the legislative limits. Alcohol was detected in 25.3 and 49.1 percent of samples from all investigated drivers and among drivers killed in single-vehicle accidents, respectively. Psychoactive medications were found in 14.4 and 17.7 percent and illicit drugs in 14.1 and 19.2 percent, respectively. The most commonly detected group of medications was benzodiazepines, and amphetamines and tetrahydrocannabinol were the most commonly detected illicit drugs. The prevalence of alcohol alone was highest among drivers under the age of 25, and the combination of alcohol with other drugs was highest among drivers under the age of 35. Drivers between the ages of 25 and 54 showed the highest prevalence of medications and/or illicit drugs without the presence of alcohol. The highest prevalence of alcohol or drugs was found among drivers killed in single-vehicle accidents on weeknights (83.8%) and on weekend nights (89.3%).

CONCLUSIONS

The findings confirm that a large number of fatally injured drivers, in particular among drivers involved in single-vehicle accidents, had concentrations of alcohol or drugs above the new legislative limits introduced in 2012. In many cases, concentrations of at least 5 times the limits were found. The proportion of drivers killed who tested positive for alcohol or other drugs did not change during the study period; however, the total number of drivers killed per year decreased by about 20 percent. Some changes were also observed with regard to the types of benzodiazepines and amphetamines detected during the 10-year period.

In the Zzz zone: the effects of Z-drugs on human performance and driving

Despite their improved pharmacokinetic profile, the Z-drugs, zolpidem, zopiclone, and zaleplon, have a spectrum of adverse effects comparable to benzodiazepines. This review focuses on the impairment from Z-drugs on cognition, behavior, psychomotor performance, and driving ability. Z-drugs are short-acting GABA agonists that reduce sleep latency without disturbing sleep architecture. Bizarre behavioral effects have prompted warnings on the prescription, dispensation, and use of Z-drugs. Psychomotor impairment, falls, and hip fractures are more likely to occur with Z-drugs that have longer half-lives, that are taken at higher-than-recommended doses and when mixed with other psychoactive substances including alcohol. Zopiclone and higher doses of zolpidem are more likely to cause anterograde amnesia than zaleplon. Z-drugs, especially zolpidem, are associated with complex behaviors such as sleepwalking, sleep-driving, and hallucinations. Patients taking zopiclone and zolpidem have an increased risk of motor vehicle collisions, over double that of unexposed drivers. Driving impairment occurs with zopiclone and higher doses of zolpidem but is unlikely to occur after 4 h post-zaleplon administration. The residual effect of Z-drugs on next-day cognitive and psychomotor performance has significant impact on lifestyle, safety, and occupational considerations, including motor vehicle and machine operation. The risk-benefit analysis of Z-drugs in the treatment of insomnia, particularly in the elderly, may not favor treatment due to the increased risks of falls and motor vehicle collisions. Prescribers should warn patients taking Z-drugs of minimum time thresholds before they operate machinery or drive motor vehicles.

Exercise increases plasma THC concentrations in regular cannabis users

BACKGROUND

The major psychoactive ingredient of cannabis, Δ(9)-tetrahydrocannabinol (THC) accumulates in fat tissue from where it slowly diffuses back into blood. THC pre-treated rats can show elevated plasma cannabinoid levels when subjected to conditions that promote fat utilization, such as fasting. Here we examine whether fasting and exercise increase plasma THC concentrations in regular cannabis users.

METHODS

Fourteen regular cannabis users completed 35 min of exercise on a stationary bicycle in either a fed or overnight fasted state. Plasma cannabinoid levels were assessed prior to exercise, immediately post-exercise and 2h post-exercise. Plasma samples were also analyzed for indices of lipolysis (free fatty acids (FFA) and glycerol).

RESULTS

Exercise induced a small, statistically significant increase in plasma THC levels accompanied by increased plasma FFA and glycerol levels. Exercise-induced increases in plasma THC concentrations were positively correlated with body mass index. Fasting induced a significant increase in plasma FFA levels, and a lowering of blood glucose, but did not significantly alter plasma cannabinoid levels.

CONCLUSIONS

Here we demonstrate that exercise enhances plasma THC levels in regular cannabis users. The lack of a fasting effect may reflect the modest duration of fasting used which was associated with only a modest increase in fat utilization relative to exercise. Overall, these results suggest that exercise may elevate blood THC levels by releasing dormant THC from fat stores. These data suggest the interpretation of blood THC levels in roadside and workplace tests might be complicated by recent exercise.

Concentrations of alprazolam in blood from impaired drivers and forensic autopsies were not much different but showed a high prevalence of co-ingested illicit drugs

Alprazolam is a benzodiazepine anxiolytic widely prescribed for treatment of panic-disorder and social phobias, although this medication is also subject to abuse. In this paper, the concentrations of alprazolam in venous blood samples from impaired drivers were compared with femoral blood samples from forensic autopsies classified as intoxication or other causes of death (e.g. natural, trauma). After liquid-liquid extraction (n-butyl acetate) alprazolam was determined in blood by capillary gas chromatography with a nitrogen-phosphorous detector. The mean (median) and range of alprazolam concentrations in blood from impaired drivers (n = 773) were 0.08 mg/L (0.05 mg/L) and 0.02-3.9 mg/L, respectively. Many traffic offenders had co-ingested ethanol (13%), amphetamine (46%), cannabis (32%), or heroin (14%), as well as other drugs. In deaths attributed to drug intoxication, the mean (median) and range of alprazolam concentrations in blood (n = 438) were 0.10 mg/L (0.06 mg/L) and 0.02-1.6 mg/L, respectively, which were not much different from other causes of death (n = 278); 0.08 mg/L (0.05 mg/L) and 0.02-0.9 mg/L. Median concentrations of alprazolam in blood from living and deceased persons did not seem to depend on the number of co-ingested substances. The result of this pharmacoepidemiological study suggests that alprazolam is a fairly innocent drug when used as monotherapy, but toxicity problems arise when co-ingested with illicit drugs and/or psychoactive medication.

Determination of buprenorphine, fentanyl and LSD in whole blood by UPLC-MS-MS

A sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method has been developed and validated for the quantification of buprenorphine, fentanyl and lysergic acid diethylamide (LSD) in whole blood. Sample preparation was performed by liquid-liquid extraction (LLE) with methyl tert-butyl ether. UPLC-MS-MS analysis was performed with a mobile phase consisting of ammonium formate (pH 10.2) and methanol. Positive electrospray ionization MS-MS detection was performed with two multiple reaction monitoring transitions for each of the analytes and the deuterium labeled internal standards. Limit of detection values of buprenorphine, fentanyl and LSD were 0.28, 0.044 and 0.0097 ng/mL and limit of quantification values were 0.94, 0.14 and 0.036 ng/mL, respectively. Most phospholipids were removed during LLE. No or only minor matrix effects were observed. The method has been routinely used at the Norwegian Institute of Public Health since September 2011 for qualitative and quantitative detections of buprenorphine, fentanyl and/or LSD in more than 400 whole blood samples with two replicates per sample.

Norwegian roadside survey of alcohol and drug use by drivers (2008-2009)

OBJECTIVE

To examine alcohol and drug use among random drivers in different regions of Norway by analyzing oral fluid, compare drivers in urban and rural areas, compare with results from the roadside survey in southeastern Norway in 2005-2006, and roughly estimate the prevalence of driving with blood drug concentrations above the new Norwegian legislative limits among random drivers. This roadside survey was part of the European DRUID (Driving Under the Influence of Drugs, Alcohol and Medicines) Project.

METHODS

Drivers were selected for a voluntary and anonymous study using a stratified multistage cluster sampling procedure in collaboration with the Mobile Police Service. Samples of oral fluid were taken using the Statsure Saliva Sample (Statsure Diagnostic Systems, Framingham, MA), and the drivers' gender, age, and nationality were recorded. Samples of oral fluid were analyzed for alcohol or drugs, for a total 28 psychoactive substances.

RESULTS

One hundred eighty-four roadside survey sessions were conducted and 10,004 drivers were asked to participate. The refusal rate was 5.8 percent. Psychoactive substances were found in 4.8 percent of the 9410 oral fluid samples analyzed. Alcohol was detected in 0.3 percent, medicinal drugs in 3.2 percent, and illegal drugs in 1.5 percent of the samples. Illegal drugs were significantly more frequently detected in samples from southeastern Norway including the capital Oslo, whereas medicinal drugs were more frequently detected in samples from southeastern Norway excluding Oslo. Illegal drugs were significantly more frequently detected in samples from drivers in urban areas than in rural areas, though there were no significant differences for alcohol and medicinal drugs. Medicinal drugs were most commonly found in samples collected during the daytime on weekdays (3.8%), and illegal drugs were most commonly found in samples collected during late night on weekdays or weekends (2.8%-3.2%). The most commonly found substances were the sleeping agent zopiclone (1.4%), the main active substance in cannabis tetrahydrocannabinol (1.1%), and the sedative drug diazepam (0.7%). The prevalence of driving with drug concentrations above the Norwegian legislative limits for blood was estimated to be about 0.2 percent for alcohol, 0.6 percent for illegal drugs, and about 1.3 percent for medicinal drugs.

CONCLUSIONS

The incidence of drink driving was very low, though driving after using psychoactive illegal or medicinal drugs was more frequent.

Alcohol, psychoactive substances and non-fatal road traffic accidents--a case-control study

Background

The prevalence of alcohol and other psychoactive substances is high in biological specimens from injured drivers, while the prevalence of these psychoactive substances in samples from drivers in normal traffic is low. The aim of this study was to compare the prevalence of alcohol and psychoactive substances in drivers admitted to hospital for treatment of injuries after road traffic accidents with that in drivers in normal traffic, and calculate risk estimates for the substances, and combinations of substances found in both groups.

Methods

Injured drivers were recruited in the hospital emergency department and drivers in normal conditions were taken from the hospital catchment area in roadside tests of moving traffic. Substances found in blood samples from injured drivers and oral fluid samples from drivers in moving traffic were compared using equivalent cut off concentrations, and risk estimates were calculated using logistic regression analyses.

Results

In 21.9% of the injured drivers, substances were found: most commonly alcohol (11.5%) and stimulants eg. cocaine or amphetamines (9.4%). This compares to 3.2% of drivers in normal traffic where the most commonly found substances were z-hypnotics (0.9%) and benzodiazepines (0.8%). The greatest increase in risk of being injured was for alcohol combined with any other substance (OR: 231.9, 95% CI: 33.3- 1615.4, p < 0.001), for more than three psychoactive substances (OR: 38.9, 95% CI: 8.2- 185.0, p < 0.001) and for alcohol alone (OR: 36.1, 95% CI: 13.2- 98.6, p < 0.001). Single use of non-alcohol substances was not associated with increased accident risk.

Conclusion

The prevalence of psychoactive substances was higher among injured drivers than drivers in normal moving traffic. The risk of accident is greatly increased among drivers who tested positive for alcohol, in particular, those who had also ingested one or more psychoactive substances. Various preventive measures should be considered to curb the prevalence of driving under the influence of psychoactive substances as these drivers constitute a significant risk for other road users as well as themselves.

Concentrations of diazepam and nordiazepam in 1,000 blood samples from apprehended drivers--therapeutic use or abuse of anxiolytics?

Using an in-house forensic toxicology database, we selected 1000 cases of driving under the influence of drugs (DUIDs) over a 12-month period if diazepam (D) and nordiazepam (ND) were both present in the blood samples. Quantitative analysis of D and ND in blood was done by solvent extraction (butyl acetate) and capillary column gas chromatography (GC) with a nitrogen-phosphorous (N-P) detector. The limits of quantitation of this analytical method for D and ND in blood were 0.05 mg/L. The correlation between D and ND concentrations in blood was statistically significant (r = .58, P < .001), as expected for a parent drug and its primary metabolite. However, the frequency distributions were markedly skewed to the right with mean (median) and highest concentrations of 0.37 (0.20) and 6.1 mg/L for D and 0.39 (0.20) and 5.6 mg/L for ND. The mean (median) total concentration (D + ND) was 0.76 mg/L (0.50 mg/L), and the concentration ratios D/ND and ND/D were 1.29 (median 0.95) and 1.41 (median 1.06), respectively. In 90 cases (9%), the concentration of D in blood exceeded 0.83 mg/L, which corresponds to an upper therapeutic limit in plasma (∼1.5 mg/L), assuming a plasma/blood distribution ratio of 1.8:1.