Testing for benzodiazepine inebriation--relationship between benzodiazepine concentration and simple clinical tests for impairment in a sample of drugged drivers

Driving under the influence of cocaine and MDMA: Relationship between blood concentrations and results from clinical test of impairment

The general use of cocaine is increasing in recent years, while the trend for 3,4-methylenedioxymethamphetamine (MDMA) is less clear. The relationship between blood concentrations and impairment is poorly understood, which complicates interpretation. The aims of this study were to report prevalence and blood concentrations of cocaine and MDMA in drugged drivers, and to investigate the relationship between blood concentrations and impairment. Samples of whole blood were collected from apprehended drivers in the period 2000-2022, and a clinical test of impairment (CTI) was simultaneously performed. The samples were initially analyzed for cocaine and MDMA using gas chromatography-mass spectrometry (until 2009 and 2012, respectively), and later using ultra-high-performance liquid chromatography-tandem mass spectrometry. Overall, cocaine was detected in 2,331 cases and MDMA in 2,569 cases. There were 377 and 85 mono cases of cocaine and MDMA, respectively. In the mono cases, the median cocaine concentration was 0.09 mg/L (range: 0.02-1.15 mg/L), and 54% of the drivers were clinically impaired. The median MDMA concentration was 0.19 mg/L (range: 0.04-1.36 mg/L), and 38% were clinically impaired. There was a statistically significant difference in the median cocaine concentration between drivers assessed as not impaired (0.07 mg/L) and drivers assessed as impaired (0.10 mg/L) (P = 0.009). There was also a significant effect of the blood concentration of cocaine (adjusted odds ratio [aOR] = 6.42, 95% confidence interval [CI] = 1.13-36.53, P = 0.036) and driving during the evening/night-time (aOR = 2.17, 95% CI = 1.34-3.51, P = 0.002) on the probability of being assessed as impaired on the CTI. No significant differences were found for MDMA. Many drivers are not assessed as impaired on a CTI following cocaine or especially MDMA use. For cocaine, a relationship between blood concentrations and impairment was demonstrated, but this could not be shown for MDMA.

Recommendations for effective collaboration and capacity building in epidemiological studies on the effect of alcohol and drug use on traffic safety in low- and middle-income countries

OBJECTIVE

Alcohol or drug impairment is a major risk factor for road traffic crashes, and studies on this issue are essential to provide evidence-based data for policymakers. In low- and middle-income countries (LMICs), such studies are often conducted in partnership with one or more organizations in high-income countries (HICs). The aim of this article is to provide recommendations for improving project planning and decision-making processes in epidemiological studies on alcohol, drug and traffic safety in LMICs involving HICs.

METHODS

We searched Pubmed, Google Scholar, and Google Search for articles and reports in English about lessons learned when conducting collaborative research in LMIC as well as papers presenting recommendations for effective research collaboration with partners in LMICs.

RESULTS

Based on the search results, we selected 200 papers for full text examination. Few were related to studies on the effect of alcohol or drug use on road traffic safety. However, several conclusions and recommendations from other studies were found to be relevant. We combined the findings with our own experience in a narrative review. We also present a checklist for risk and quality assessment.

CONCLUSIONS

Many papers presented similar recommendations, which included the importance of addressing local needs, ensuring adequate resources, local project ownership and leadership, establishing strong partnerships among all involved stakeholders, promoting shared decision-making and planning, and implementing strategies to translate research findings into policy, practice, and publications. It is also important to avoid HIC bias, which prioritizes the interests or perspectives of HICs over those of LMICs.

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.

Development of a New LC-MS/MS Screening Method for Detection of 120 NPS and 43 Drugs in Blood

In the last few years, liquid chromatography coupled with mass spectrometry (LC/MS) has been increasingly used for screening purposes in forensic toxicology. These techniques have the advantages of low time/resource-consuming and high versatility and have been applied in numerous new multi-analytes methods. The new psychoactive substance (NPS) phenomenon provided a great impulse to this wide-range approach, but it is also important to keep the attention on “classical” psychoactive substances, such as benzodiazepines (BDZ). In this paper, a fully validated screening method in blood for the simultaneous detection of 163 substances (120 NPS and 43 other drugs) by a dynamic multiple reaction monitoring analysis through LC-MS/MS is described. The method consists of a deproteinization of 200 µL of blood with acetonitrile. The LC separation is achieved with a 100 mm long C18 column in 35 min. The method was very sensitive, with limits of quantification from 0.02 to 1.5 ng/mL. Matrix effects did not negatively affect the analytical sensitivity. This method proved to be reliable and was successfully applied to our routinary analytical activity in several forensic caseworks, allowing the identification and quantification of many BDZs and 3,4-methylenedioxypyrovalerone (MDPV).

Blood Concentrations of Designer Benzodiazepines: Relation to Impairment and Findings in Forensic Cases

The use of designer benzodiazepines appears to be increasing in many countries, but data concerning blood concentrations are scarce, making interpretation of concentrations difficult. The aim of this study was to report blood concentrations of clonazolam, diclazepam, etizolam, flualprazolam, flubromazepam, flubromazolam and phenazepam and to investigate the relationship between blood concentrations and impairment. The concentration data are from blood samples collected from living cases (apprehended drivers and other drug offences) and medico-legal autopsies. The blood samples were analysed for the seven designer benzodiazepines mentioned above by ultra high performance liquid chromatography–tandem mass spectrometry. Positive cases from between 1 June 2016 and 30 September 2019 were included. Blood concentrations and the conclusion from a clinical test of impairment (when available) are reported. The presented seven benzodiazepines were detected in a total of 575 cases, where 554 of these cases concerned apprehended drivers or other criminal offenders. The number of findings and the median (range) concentrations were as follows: clonazolam, n = 22, 0.0041 mg/L (0.0017–0.053 mg/L); diclazepam, n = 334, 0.0096 mg/L (0.0016–0.25 mg/L); etizolam, n = 40, 0.054 mg/L (0.015–0.30 mg/L); flualprazolam, n = 10, 0.0080 mg/L (0.0033–0.056 mg/L); flubromazepam, n = 5, 0.037 mg/L (0.0070–0.70 mg/L); flubromazolam, n = 20, 0.0056 mg/L (0.0004–0.036 mg/L); and phenazepam, n = 138, 0.022 mg/L (0.0018–0.85 mg/L). A designer benzodiazepine was the only drug detected with relevance for impairment in 25 of the 554 living cases. The physician concluded with impairment in 19 of the 25 cases. Most of the concentrations in these cases were relatively similar to or higher than the median reported concentrations. The most frequent other drugs detected were amphetamine, tetrahydrocannabinol, clonazepam and methamphetamine. The presented blood concentrations can be helpful with the interpretation of cases involving one or more of these seven benzodiazepines. The results indicate that concentrations commonly observed in forensic cases are associated with impairment.

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.

The Transcriptional Signature of a Runner's High

INTRODUCTION

Endorphins, endocannabinoids, monoamines, and neurotrophins have all been implicated in the euphoric response to endurance running, known as a runner's high (RH). The epitranscriptional mechanisms regulating this effect have not been defined. Here, we investigate peripheral micro-ribonucleic acid (miRNA) changes unique to athletes experiencing postrun euphoria, yielding insights into gene networks that control an RH.

METHODS

A cohort study involving 25 collegiate runners (48% females, age = 20 ± 1 yr) examined salivary RNA levels before and after a long-distance run. Participants were divided into RH and nonrunner's high (NRH) groups based on surveys of four criteria (mood, lost sense of time, run quality, and euphoria). Physiological measures were also recorded (temperature, heart rate, blood pressure, pupillary dilatation, and salivary serotonin). Levels of miRNAs and their messenger RNA targets were compared across pre- and postrun samples from RH and NRH groups with two-way ANOVA. Representation of opioid, gamma-aminobutyic acid (GABA), endocannabinoid, neurotrophin, serotonergic, and dopaminergic pathways was assessed in DIANA miRPath. Pearson's correlation analyses examined relationships between miRNAs and RH indices.

RESULTS

RH participants (n = 13) demonstrated postrun mydriasis (P = 0.046) and hypothermia (P = 0.043) relative to NRH participants (n = 12) but had no difference in serotonin dynamics (P = 0.88). Six miRNAs (miR-194-5p, miR-4676-3p, miR-4254, miR-4425, miR-1273-3p, miR-6743-5p) exhibited significant effects (false discovery rate P value < 0.05) across pre- or postrun and RH/NRH groups. These miRNAs displayed target enrichment for opioid (P = 2.74E-06) and GABA (P = 0.00016) pathways. miR-1237-3p levels were related with lost sense of time (R = 0.40). Mitogen-activated protein kinase (MAPK11), an endocannabinoid target of miR-1273-3p, was nominally elevated in RH participants (false discovery rate P value = 0.11).

CONCLUSIONS

Unique dynamics in miRNA concentration occur in athletes with subjective/objective evidence of RH, targeting genes implicated endorphin, endocannabinoid, and GABAergic signaling.

THC and CBD in blood samples and seizures in Norway: Does CBD affect THC-induced impairment in apprehended subjects?

BACKGROUND AND AIMS

Several publications have suggested increasing cannabis potency over the last decade, which, together with lower amounts of cannabidiol (CBD), could contribute to an increase in adverse effects after cannabis smoking. Naturalistic studies on tetrahydrocannabinol (THC) and CBD in blood samples are, however, missing. This study aimed to investigate the relationship between THC- and CBD concentrations in blood samples among cannabis users, and to compare cannabinoid concentrations with the outcome of a clinical test of impairment (CTI) and between traffic accidents and non-accident driving under the influence of drugs (DUID)-cases. Assessment of THC- and CBD contents in cannabis seizures was also included.

METHODS

THC- and CBD concentrations in blood samples from subjects apprehended in Norway from April 2013-April 2015 were included (n=6134). A CTI result was compared with analytical findings in cases where only THC and/or CBD were detected (n=705). THC- and CBD content was measured in 41 cannabis seizures.

RESULTS

Among THC-positive blood samples, 76% also tested positive for CBD. There was a strong correlation between THC- and CBD concentrations in blood samples (Pearson's r=0.714, p<0.0005). Subjects judged as impaired by a CTI had significantly higher THC- (p<0.001) and CBD (p=0.008) concentrations compared with not impaired subjects, but after multivariate analyses, impairment could only be related to THC concentration (p=0.004). Analyzing seizures revealed THC/CBD ratios of 2:1 for hashish and 200:1 for marijuana.

CONCLUSIONS

More than ¾ of the blood samples testing positive for THC, among subjects apprehended in Norway, also tested positive for CBD, suggesting frequent consumption of high CBD cannabis products. The simultaneous presence of CBD in blood does, however, not appear to affect THC-induced impairment on a CTI. Seizure sample analysis did not reveal high potency cannabis products, and while CBD content appeared high in hashish, it was almost absent in marijuana.

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.

Blood concentrations of new designer benzodiazepines in forensic cases

INTRODUCTION

A number of new designer benzodiazepines have reached the illegal drug market over the past years. Toxicological interpretation of concentrations of these drugs in blood is quite challenging as very limited human data have previously been published. The aim of this study was to report blood concentrations of new designer benzodiazepines in a population of drugged drivers as well as some other criminal offenders, and to relate this to clinical impairment.

METHODS

The present material represents cases involving new designer benzodiazepines (clonazolam, diclazepam, flubromazepam, flubromazolam and pyrazolam) and etizolam, submitted for analyses during the period July 1, 2013-May 31, 2016. Analyses were performed using an ultra-performance liquid chromatography-tandem mass spectrometry method. Blood concentrations and results from the clinical test of impairment are reported.

RESULTS

New designer benzodiazepines were detected in 77 cases during the study period. The median (range) concentrations were 0.012mg/L (0.00048-0.10) for flubromazolam (n=25), 0.055mg/L (0.0047-1.2) for flubromazepam (n=24), 0.013mg/L (0.0021-0.057) for diclazepam (n=15), 0.050mg/L (0.019-0.17) for etizolam (n=14), 0.0053mg/L (0.0019-0.011) for clonazolam (n=7) and 0.074mg/L for pyrazolam (n=1). In six cases, designer benzodiazepines were the only drugs detected in blood, and in two of those cases, the physician had given the conclusion of "considerably impaired" upon performing the clinical test for impairment.

CONCLUSION

Given the lack of previously published data on human concentrations, results presented in this study could be helpful in interpretation of blood concentrations of new designer benzodiazepines. This is crucial for the assessment of the importance of toxicological results in suspected drugged drivers, rape victims, etc.

Methiopropamine in blood samples from drivers suspected of being under the influence of drugs

OBJECTIVES

Methiopropamine (MPA; 1-(thiophen-2-yl)-2-methylaminopropane) belongs to the new psychoactive substances (NPS) that have emerged on the drug market in recent years. MPA appeared in 2011 and is an analogue of methamphetamine, sold as, for example, "Slush Eric" and "Blow." It is reported to have effects similar to those of methamphetamine, but the toxicity in humans is not known. Three fatal cases involving MPA have been reported. One analytical confirmed intoxication case has been published, and this supports the symptoms described by the users. The prevalence of recreational use of MPA is unknown, and no studies have reported the prevalence in driving under the influence of drug (DUID) cases.

METHODS

We investigated the frequency of MPA in DUID cases received at our institute during a 12-week period and report the analytical method using an ultraperformance liquid chromatography.tandem mass spectrometry for quantification of MPA in whole blood. The analytical findings were compared to the results from a clinical test of impairment performed by a physician shortly after the driving episode. The samples were analyzed for 42 different psychoactive substances.

RESULTS

MPA was detected in 10 DUID cases (0.8% of the cases), only from male drivers. Other drugs were detected concomitantly in all the cases. Two of the cases were traffic accidents.

CONCLUSIONS

Our study shows that MPA is found in DUID cases and reveals that NPS are used among drivers and also proven in blood from drivers involved in traffic accidents. More studies are requested regarding the pharmacological and toxicological effects of MPA and other NPS. This is the first article that describes a method for analyzing and quantifying MPA in whole blood samples.

Alcohol hangover as a cause of impairment in apprehended drivers

OBJECTIVE

Previous studies have already shown the possibility of impairment during a hangover phase, after alcohol ingestion, when the blood alcohol concentration has returned to zero. The prevalence of drivers being in a hangover phase, in the driving population, and the relation to impairment relevant for traffic safety has, however, not been previously studied. The aim of this study was to investigate the prevalence and the concentrations of the 2 ethanol metabolites, ethyl glucuronide (EtG) and ethyl sulfate (EtS), in blood, indicating very recent alcohol intake, among apprehended drivers, in which no psychoactive substances, including alcohol, were detected. The aim was also to study these findings in relation to the impairment observed in these drivers.

METHODS

Blood samples, drawn from suspected drunk or drugged drivers, were analyzed for a broad repertoire of psychoactive substances, with a clinical test for impairment (CTI) being performed at the same time. One hundred and forty-six cases, in which no psychoactive substances were detected and where a valid CTI was performed, were analyzed for EtG and EtS in blood. The prevalence and concentrations were related to the conclusions of the CTIs.

RESULTS

EtS and EtG were detected in a total of 19 of the 146 cases (13%). Among the "impaired" drivers, EtG and EtS were detected in 16 cases (18%), whereas among "not impaired" drivers they were detected in 3 cases (5%). There were significantly more detections of EtS (and EtG) among the impaired group of drivers compared to the nonimpaired drivers (P =.030), and the concentrations of both EtG (P =.027) and EtS (P =.026) were significantly higher in the group of impaired drivers compared to the nonimpaired drivers. There was a statistically significant positive correlation between the concentrations of EtG (Spearman's rho = 0.170, P =.041) and EtS (Spearman's rho = 0.189, P =.022) and the degree of impairment.

CONCLUSIONS

EtG and EtS were prevalent findings in blood collected from the apprehended drivers, testing negative for all psychoactive substances. The higher rates of detections of EtG and EtS in impaired compared to nonimpaired drivers, and also the positive correlation between concentrations of EtG and EtS and the degree of impairment, indicate that hangover symptoms may be relevant for traffic safety.

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.

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.

The methodological quality of three foundational law enforcement Drug Influence Evaluation validation studies

BACKGROUND

A Drug Influence Evaluation (DIE) is a formal assessment of an impaired driving suspect, performed by a trained law enforcement officer who uses circumstantial facts, questioning, searching, and a physical exam to form an unstandardized opinion as to whether a suspect's driving was impaired by drugs. This paper first identifies the scientific studies commonly cited in American criminal trials as evidence of DIE accuracy, and second, uses the QUADAS tool to investigate whether the methodologies used by these studies allow them to correctly quantify the diagnostic accuracy of the DIEs currently administered by US law enforcement.

RESULTS

Three studies were selected for analysis. For each study, the QUADAS tool identified biases that distorted reported accuracies. The studies were subject to spectrum bias, selection bias, misclassification bias, verification bias, differential verification bias, incorporation bias, and review bias. The studies quantified DIE performance with prevalence-dependent accuracy statistics that are internally but not externally valid.

CONCLUSION

The accuracies reported by these studies do not quantify the accuracy of the DIE process now used by US law enforcement. These studies do not validate current DIE practice.

Influence of drugs of abuse and alcohol upon patients admitted to acute psychiatric wards: physician's assessment compared to blood drug concentrations

In acute psychiatric services, rapid and accurate detection of psychoactive substance intake may be required for appropriate diagnosis and intervention. The aim of this study was to investigate the relationship between (a) drug influence as assessed by physicians and (b) blood drug concentrations among patients admitted to acute psychiatric wards. We also explored the possible effects of age, sex, and psychotic symptoms on physician's assessment of drug influence. In a cross-sectional study, the sample comprised 271 consecutive admissions from 2 acute psychiatric wards. At admission, the physician on call performed an overall judgment of drug influence. Psychotic symptoms were assessed with the positive subscale of the Positive and Negative Syndrome Scale. Blood samples were screened for a wide range of psychoactive substances, and quantitative results were used to calculate blood drug concentration scores. Patients were judged as being under the influence of drugs and/or alcohol in 28% of the 271 admissions. Psychoactive substances were detected in 56% of the blood samples. Altogether, 15 different substances were found; up to 8 substances were found in samples from 1 patient. Markedly elevated blood drug concentration scores were estimated for 15% of the patients. Physician's assessment was positively related to the blood drug concentration scores (r = 0.52; P < 0.001), to symptoms of excitement, and to the detection of alcohol, cannabis, and amphetamines. The study demonstrates the major impact of alcohol and drugs in acute psychiatric settings and illustrates the challenging nature of the initial clinical assessment.

The effect of trazodone on standardized field sobriety tests

STUDY OBJECTIVE

To evaluate the effects of a single dose of trazodone on the standardized field sobriety test (SFST).

DESIGN

A randomized, double-blinded, repeated-measures study.

PARTICIPANTS

Forty-five healthy adult subjects.

SETTING

University campus.

MEASUREMENTS AND MAIN RESULTS

The SFST consists of the horizontal gaze nystagmus, walk-and-turn, and one-leg stand tests. Subjects were administered a baseline SFST and at 2 hours after the administration of either trazodone 100 mg (30 subjects) or acetaminophen 650 mg (15 subjects). At 2 hours post drug administration, there were no statistical differences in failure rates between the trazodone and acetaminophen groups (53.3% vs 20.0%, p=0.054). However, the trazodone group exhibited more impairment clues within the individual tests of the SFST than the acetaminophen group.

CONCLUSIONS

A one-time dose of trazodone 100 mg does not result in an increased SFST failure rate at 2 hours postdosing compared to acetaminophen 650 mg. However, the number of individual impairment clues detected is increased with trazodone. Trazodone 100 mg may cause cognitive driving impairment.

Concentrations of drugs determined in blood samples collected from suspected drugged drivers in England and Wales

This communication reports the blood concentrations of alcohol and drugs from 376 cases of alleged driving under the influence of drugs analysed at the Forensic Science Service Chorley and London laboratories between February 2010 and March 2011. The samples were analysed for alcohol, amphetamine, benzodiazepines, cocaine, MDMA, opiates, γ-hydroxybutyrate (GHB), ketamine, methadone and methylmethcathinone (the 4-isomer of which is known as mephedrone). The results were interpreted with respect to the number and type of drugs of abuse detected and the concentrations measured. Alcohol was quantified in 113 cases (30%), and of these a level in excess of the prescribed UK limit for driving of 80 mg% was present in 90 cases. In 80 cases, only the concentration of alcohol was measured, the concentrations of both drugs and alcohol were measured in 33 cases. In the remaining 263 cases, only the concentrations of relevant drugs of abuse were measured. The most common drug of abuse quantified was cocaine which was detected in 92 cases, either as the active drug or as its major metabolite benzoylecgonine, followed by diazepam which was quantified in 76 cases. Concentrations of some new drugs, and drugs rarely reported in driving under the influence cases are also presented.

Judging intoxication

Judgments of whether a person is intoxicated by alcohol are important in a number of civil and law enforcement settings. This paper reviews how well people are able to make such judgments, the evidence for individual signs of intoxication, several structured rating techniques, and the use of sobriety tests. It is concluded that observers relying on common-sense clues of intoxication have limited ability to assess the blood alcohol concentration (BAC) levels of strangers, particularly below .10%. This generalization holds across professions that might be expected to show greater accuracy. Structured assessment instruments based on observable signs have shown promise but are confounded by the wide variations between casual social drinkers and those that have obtained a high level of tolerance. Among sobriety tests, only NHTSA's Standardized Field Sobriety Tests (SFSTs) have substantial, but seriously flawed, research support. Assessing the sobriety of strangers in the low to moderate BAC ranges without resort to chemical tests remains a daunting task.

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

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

Drug poisoning deaths in Sweden show a predominance of ethanol in mono-intoxications, adverse drug-alcohol interactions and poly-drug use

Over a 10-year period (1998-2007) all deaths in Sweden classified by forensic pathologists as fatal drug poisonings (N = 6894) were retrieved from a toxicology database (TOXBASE) belonging to the National Board of Forensic Medicine. The deaths were further classified as suicides N = 2288 (33%), undetermined N = 2260 (33%) and accidental N = 2346 (34%). The average age (± SD) of all victims was 49.1 ± 15.9 years and men 47.4 ± 15.6 years were 5-year younger than women 52.2 ± 15.8 years (p < 0.01). Most of the deceased (78%) were poly-drug users although a single drug (mono-intoxications) was found in 22% of all poisoning deaths (p < 0.001). The number of drugs in blood samples varied from 1 to 12 with a median of 3-4 per case. Mono-intoxication deaths were mostly ethanol-related (N = 976) and the mean and median blood-alcohol concentration (BAC) was 3.06 g/L and 3.10 g/L, respectively. The BAC decreased as the number of additional drugs in blood increased from 2.15 g/L with one drug to 1.25 g/L with 6 or more drugs. The mean (median) concentrations of non-alcohol drugs in mono-intoxication deaths were morphine (N = 93) 0.5mg/L (0.2mg/L), amphetamine (N = 39) 2.0mg/L (1.2mg/L), dextropropoxyphene (N = 33) 3.9 mg/L (2.9 mg/L), dihydro-propiomazine (N = 32) 1.6 mg/L (1.0mg/L) and 7-amino-flunitrazepam (N = 28), 0.4 mg/L (0.3mg/L). Elevated blood morphine in these poisoning deaths mostly reflected abuse of heroin as verified by finding 6-monoacetyl morphine (6-MAM) in the blood samples. When investigating drug poisoning deaths a comprehensive toxicological analysis is essential although the results do not reveal the extent of prior exposure to drugs or the development of pharmacological tolerance. The concentrations of drugs determined in post-mortem blood are one element in the case. The autopsy report, the police investigation, the findings at the scene and eye-witness statements should all be carefully considered when the cause and manner of death are determined.

Impairment due to cannabis and ethanol: clinical signs and additive effects

AIMS

Studies have shown that the impairing effects of Delta-9-tetrahydrocannabinol (THC) are dose-related. Cannabis intake increases the risk of traffic accidents. The purpose of this study was to see how different clinical tests and observations were related to blood THC concentrations and to determine whether the combined influence of THC and ethanol was different from either drug alone.

DESIGN

A retrospective cross-sectional forensic database study.

SETTING

Drivers apprehended by the police suspected of driving under the influence of alcohol and other drugs.

PARTICIPANTS

We investigated 589 cases positive for THC only. In addition, 894 cases with THC and ethanol were included. A comparison was made with 3480 drivers with only ethanol in their blood and 79 drivers who tested negative.

MEASUREMENTS

Data were analytical results of blood samples and the 27 clinical tests and observations included in the Norwegian clinical test for impairment (CTI).

FINDINGS

No relationship was found between blood THC concentration and most of the CTI tests. Blood THC concentration was, however, related to conjunctival injection, pupil dilation and reaction to light and to the overall risk of being judged impaired. When THC and ethanol were detected together the risk of being judged impaired was increased markedly.

CONCLUSIONS

This study demonstrates that cannabis impairs driving ability in a concentration-related manner. The effect is smaller than for ethanol. The effect of ethanol and cannabis taken simultaneously is additive. Conjunctival injection, dilated pupils and slow pupil reaction are among the few signs to reveal THC influence.

Impairment related to blood drug concentrations of zopiclone and zolpidem compared to alcohol in apprehended drivers

BACKGROUND

About 3-7% of the adult population receives prescribed hypnotics. The benzodiazepine-like hypnotics, zopiclone and zolpidem, are the most commonly prescribed and may cause traffic-relevant impairment similar to that found for benzodiazepines. We investigated the relationship between blood zopiclone and zolpidem concentrations and driving impairment, as assessed by the clinical test for impairment. We compared these groups of drivers to a group suspected of alcohol-related impairment.

METHODS

Blood samples from suspected impaired drivers during 2000-2007, screened for approximately 25 possible impairing drugs with only one single drug detected, were studied in relation to the assessment of impairment. The 79 zopiclone positive drivers, the 43 zolpidem positive drivers, and the 3480 alcohol positive drivers were divided into groups depending on blood drug concentrations.

RESULTS/DISCUSSION

The proportion of drivers judged as impaired tended to increase the higher the blood zopiclone concentrations. Such a positive relationship was not found for zolpidem. For alcohol the proportion of impaired drivers was significantly related to blood alcohol concentrations (BACs). There were few drivers with low zopiclone or zolpidem concentrations included, which may have obscured any positive significant relationship. The percentage of impaired drivers among drivers with blood zopiclone concentrations above 130 microg/l roughly corresponded to the percentage of impaired drivers among drivers with BACs higher than 0.1%.

Frequency and irregularity of heart rate in drivers suspected of driving under the influence of cannabis

BACKGROUND

Delta 9-tetrahydrocannabinol (THC) is the major active component of cannabis. Cardiovascular effects of THC have previously been reported: tachycardia after intake, but also bradycardia at higher doses. The purpose of this study was, firstly, to investigate the frequency and irregularity of heart rate in a group of cannabis users in their natural surroundings. We also compared THC-positive drivers with a regular pulse with THC-positive drivers with an irregular pulse.

METHODS

The division of Forensic Toxicology and Drug Abuse (DFTDA) at the Norwegian Institute of Public Heath analyzes blood samples from all drivers suspected of driving under the influence of drugs. We studied pulse rate and regularity in 502 THC-positive drivers who tested negative for other substances. As a control group, we randomly selected 125 drug-negative cases from the database of the DFTDA; no alcohol, narcotics, or medicinal drugs of abuse were detected.

RESULTS

The Delta9-THC-positive drivers had a higher mean pulse rate than the control group [82.8 beats/min (SD 16.3) versus 75.6 beats/min (SD 9.2)] and more cases with tachycardia were detected in the Delta9-THC-positive group (19.4% versus 1.6%). There was only one driver with an irregular heart beat in the control group, while there were nine among the Delta9-THC-positive drivers. The drivers with an irregular pulse were over-represented amongst those with the lowest blood Delta9-THC concentrations.

CONCLUSION

This report represents a large study of subjects in a real-life situation and includes observations on pulse frequency, regularity, and blood Delta9-THC concentration. A substantial fraction of Delta9-THC-positive drivers had tachycardia, but there was no correlation between blood Delta9-THC concentration and pulse rate in the present study. We had no further diagnostic information on the cause of the pulse irregularities, but our results indicate that occasional users of cannabis tend to have irregular heart rates at low THC concentrations and at low pulse rates.

[Illicit drugs, medications and traffic accidents]

The European Union (EU) has 25 member-states and 455 million inhabitants. Statistics on traffic accidents in the EU show that more than 45,000 people are killed annually, including 5200 in France. At the same time, nearly two million persons in the EU require medical treatment for traffic-accident-related injuries, including 109,000 in France. In addition, traffic accidents are the major cause of death of those individuals aged 15 to 24 years. One third of the EU inhabitants will be hospitalized during their life due to a traffic accident with a cost over 160 billion euro (2-3% of the Gross Domestic Product). An important contributing factor to crashes is the use of alcohol and/or illicit drugs or medication when driving, as they exert negative effects on cognition and psychomotor functions. For illicit drugs, abuse of cannabis with or without alcohol is a major concern for the EU. In fact, three million Europeans use cannabis daily and 80% of them drive after use. A number of French studies since 1999 have underlined the high prevalence of cannabis found in the blood of injured or killed drivers. From medical or judicial observations, it is clear that cannabis use increases the risk of traffic accidents. Many groups outside Europe have also shown the association between drug abuse and crashes. The number of casualties related to certain medicines, especially benzodiazepines remains at a high level, particularly in the elderly. In many countries the prevalence of medicinal drugs associated with car accidents is higher than with cannabis. Annex III of the European Union Council Directive of July the 29th 1991 in fact states that a driving license should not be issued to or renewed for applicants or drivers who are dependent on psychotropic substances or use them regularly. Recently, France has categorized the medicinal drugs available in the country by using three pictograms: level one yellow, "be careful"; level two orange, "be very careful"; level three red, "don't drive". It is an important campaign that increases awareness among the public and the medical professionals about the potential dangerous effects of medicinal drugs when driving. The EU objective of reducing the number of fatalities to 25,000 by 2010 will require strengthening measures against the use of alcohol, illicit and medicinal drugs by not well-informed drivers. It is not only a really great challenge, but also a significant investment towards improving public health in France as well as in Europe.

The Standardized Field Sobriety Tests: a review of scientific and legal issues

This article details the history and development of the National Highway and Safety Administration's Standardized Field Sobriety Tests. They are reviewed in terms of relevant scientific, psychometric, and legal issues. It is concluded that the research that supports their use is limited, important confounding variables have not been thoroughly studied, reliability is mediocre, and that their developers and prosecution-oriented publications have oversold the tests. Further, case law since their development has severed the tests from their validation data, so that they are not admissible on the criterion for which they were validated (blood alcohol concentration), and admissible for a criterion for which they were not (mental, physical, or driving impairment). Directions for further research are presented.

The relation between the blood benzodiazepine concentration and performance in suspected impaired drivers

Several experimental studies have shown a negative influence of benzodiazepines on driving skills. The objective of this study is to study the relationship between the blood concentration of benzodiazepines and the influence on performance in field sobriety tests. A retrospective case file evaluation was conducted to select cases of drivers, tested positive for benzodiazepines only in the period from January 1999 to December 2004. Drivers were grouped into the categories sub therapeutic, therapeutic or elevated concentrations. The outcome of the tests (walking, walking after turn, nystagmus, Romberg's test, behavior, pupils and orientation) was binomial. A Chi square test was used to assess differences in proportions of the categorized cases. In total 171 cases were included. Observations of behavior (n=137; p<0.01), walking (n=109; p<0.01), walking after turn (n=89; p=0.02) and Romberg's test (n=88; p<0.05) were significantly related to the benzodiazepine concentration. There was no significant relation between benzodiazepine concentration and effect on pupil size, nystagmus or orientation. The results of our study indicate a relation between the concentration of benzodiazepines and the results of some performance tests. More effort is needed to standardize the tests and to determine the sensitivity and selectivity of the tests for benzodiazepines.

The risk of traffic accidents after prescriptions of carisoprodol

OBJECTIVE

Carisoprodol, a drug used for acute lower back pain, may cause psychomotor impairment. We wanted to investigate if patients using carisoprodol had increased risk of being involved in a traffic accident.

METHODS

Data were retrieved from three population-based registries for the period April 2004-September 2005. The Norwegian Prescription Database contained individual information on all dispensed drugs at all pharmacies outside hospitals. The Norwegian Road Accident Registry contained information on all drivers involved in motor vehicle accidents with person injury. The Norwegian Central Population Registry was used to control for emigration or death. The accident incidence among carisoprodol exposed and unexposed subjects was compared by standardized incidence ratio.

RESULTS

Having a prescription for carisoprodol dispensed increased the standardized incidence ratio for being involved in an accident with person injury to 3.7 (95% CI 2.9-4.8) the first week after the date of dispensing. This was similar to diazepam (2.8; 2.2-3.6), but higher than for salbutamol (1.1; 0.6-1.8).

CONCLUSIONS

Patients receiving carisoprodol seem to have an increased risk of being involved in traffic accidents involving person injury. The study gives support to earlier work published on the impairing effects of carisoprodol.

Age- and gender-related differences in blood amphetamine concentrations in apprehended drivers: lack of association with clinical evidence of impairment

BACKGROUND

New legislation aimed at combating driving under the influence of drugs (DUID) in Sweden stipulated zero-concentrations in blood for scheduled substances. DUID suspects (n = 300), with amphetamine as the only psychoactive drug identified in blood, were investigated in relation to age and gender. In a smaller retrospective sample (n = 70) the relationship between clinical tests of impairment were compared with the concentration of amphetamine in blood.

MEASUREMENTS

All forensic blood samples were subjected to a broad toxicological screening analysis by immunoassay methods [enzyme multiplied immunoassay technique/cloned enzyme donor immunoassay (EMIT/CEDIA)] and positive results were verified by gas chromatography-mass spectrometry (GC-MS). The limit of quantitation (LOQ) for determination of amphetamine in blood was 0.03 mg/l. People suspected of being under the influence of drugs were examined by a physician who asked various questions about state of health and use of drugs and also administered simple psychomotor and cognitive tests of impairment. After conducting these tests the physician concluded whether the suspects were not impaired, slightly, moderately or highly impaired by drugs other than alcohol.

FINDINGS

Among 300 DUID suspects with amphetamine in blood there were 246 men (82%) and 54 women (18%). Mean age (+/- SD) of the men was 37.1 +/- 8.7 years compared with 35.5 +/- 7.1 years for the women (P > 0.05). The frequency distribution of blood amphetamine concentration was positively skewed with mean, median and highest values of 1.0 mg/l, 0.9 mg/l and 7.1 mg/l, respectively. The mean concentrations were slightly higher in the women 1.11 mg/l (median 1.0 mg/l) compared with 0.97 mg/l (median 0.8 mg/l) in the men (P > 0.05). There was a weak but statistically significant correlation between the person's age and the concentration of amphetamine in blood (r = 0.18, P < 0.05). The results of clinical tests of impairment showed no relationship with the concentration of amphetamine in blood according to analysis of variance (P > 0.05).

CONCLUSIONS

The lack of association between degree of drug influence and the concentration of amphetamine in blood speaks against the notion of introducing concentration per se limits or graded penalties depending on the blood-concentration of this stimulant. Zero-concentration limits or LOQ-limits are a much more pragmatic way to enforce DUID legislation.

Heroin-using drivers: importance of morphine and morphine-6-glucuronide on late clinical impairment

OBJECTIVE

To evaluate the relationship between major heroin metabolites (morphine, morphine-6-glucoronide), pattern of drug use, and late impairment of psychomotor functions.

METHODS

From the database of the Norwegian Institute of Public Health, Oslo, blood morphine concentration in samples from heroin users (n=70) containing only morphine were correlated with results of the clinical test for impairment (CTI). For comparison, test results were explored in individuals without any positive analytical finding in blood samples (n=79) selected from the same database.

RESULTS

In the "no drug" cases, 86% were judged as not impaired and 14% as impaired. In the morphine only cases, 20% were judged as not impaired, and 80% as impaired. Both daily users and non-daily users had the same proportion of impaired cases. Median blood morphine concentration (M) was 0.09 micromol/l in the "not impaired" group and 0.15 micromol/l in the "impaired" group (P=0.067). For morphine-6-glucuronide (M6G), the median blood concentration was 0.09 micromol/l in the "not impaired" group and 0.14 micromol/l in the "impaired" group (P=0.030). A significant correlation between concentration quartiles and number of cases determined as "impaired" was found for M6G (P=0.018) and for the sum M+M6G (P=0.013).

CONCLUSION

In our population of heroin-drugged drivers, blood concentrations of M6G and the sum M+M6G appeared to have concentration-dependent effects on the CNS that may lead to impairment as judged from a CTI. Variations in pattern of use did not seem to have any bearing on the judgement of impairment.

Impairment related to blood amphetamine and/or methamphetamine concentrations in suspected drugged drivers

Experimental studies have investigated effects of low oral doses of amphetamine and methamphetamine on psychomotor functions, while less work has been done on effects of high doses taken by abusers in real-life settings. There are indications that intake of high doses may impair traffic related skills, and that abuse of amphetamines may cause hypersomnolence at the end-of-binge. The present study aimed at investigating the concentration-effect relationship between blood amphetamines concentrations and impairment in a population of real-life users. Eight hundred and seventy-eight cases with amphetamine or methamphetamine as the only drugs present in the blood samples were selected from the impaired driver registry at The Norwegian Institute of Public Health. In each case the police physician had concluded on whether the driver was impaired or not. 27% of the drivers were judged as not impaired, while 73% were judged as impaired. There was a positive relationship between blood amphetamines concentrations and impairment. The relationship reached a ceiling at blood amphetamines concentrations of 0.27-0.53 mg/l. Younger drivers were more often judged impaired than older drivers at similar concentrations. Despite the performance enhancing qualities of amphetamines demonstrated in some low dose laboratory experiments; this study revealed a positive relationship between blood amphetamines concentration and traffic related impairment.

Driving under the influence of drugs in Sweden with zero concentration limits in blood for controlled substances

OBJECTIVE

This article describes the background and implementation in Sweden of zero-concentration limits for controlled drugs in the blood of drivers. Eliminating the need to prove that a person's ability to drive safely was impaired by drugs has greatly simplified the prosecution case, which now rests primarily on the forensic toxicology report. Driving under the influence of a prescription drug listed as a controlled substance is exempt from the zero-limit law provided the medication was being used in accordance with a physician's direction and the person was not considered unfit to drive.

METHODS

The prevalence of driving under the influence of drugs (DUID) in Sweden was evaluated from police reports with the main focus on the toxicological findings. A large case series of DUID suspects was compared before and after introducing zero concentration limits in blood for controlled substances on July 1, 1999. The spectrum of drugs used by typical offenders and the concentrations of various licit and illicit substances in blood were evaluated and compared.

RESULTS

Immediately after the zero-limit law came into force, the number of cases of DUID submitted by the police for toxicological analysis increased sharply and is currently ten-fold higher than before the new legislation. Statistics show that about 85% of all blood samples sent for toxicological analysis have one or more banned substances present. Amphetamine is by far the leading drug of abuse in Sweden and was identified in about 50-60% of all DUID suspects either alone or together with other controlled substances. The next most frequently encountered illicit drug was tetrahydrocannabinol (THC), with positive findings in about 20-25% of cases. Various prescription drugs, mainly sedative-hypnotics like diazepam and flunitrazepam, were also highly prevalent and these occurred mostly together with illicit substances. Opiates, such as 6-acetyl morphine and morphine, the metabolites of heroin, were high on the list of substances identified. Most DUID suspects in Sweden were men (85%) who were poly-drug users combining illicit substances, like amphetamine and/or cannabis, with a prescription medication such as various benzodiazepines.

CONCLUSIONS

Sweden's zero-concentration limit has done nothing to reduce DUID or deter the typical offender because recidivism is high in this population of individuals (40-50%). Indeed, many traffic delinquents in Sweden are criminal elements in society with previous convictions for drunk and/or drugged driving as well as other offenses. The spectrum of drugs identified in blood samples from DUID suspects has not changed much since the zero-limit law was introduced.

Flunitrazepam: psychomotor impairment, agitation and paradoxical reactions

Benzodiazepines are sedatives used for anxiolysis, hypnosis, muscle relaxation and the treatment of epilepsy. Paradoxical reactions including agitation, talkativeness, confusion, disinhibition, aggression, violent behavior and loss of impulse control may, however, occur in some subjects. It has been claimed that high doses of flunitrazepam may cause aggression on a more regular basis in all individuals. The present study makes use of a Norwegian forensic toxicological database containing analytical results from drivers suspected of driving under the influence and suspects of violent crime to analyze the relationship between behavior and blood flunitrazepam concentration. Four-hundred and fifteen cases of drivers suspected of driving under the influence and seven cases of suspects of violent crime were studied. These selected cases had flunitrazepam as the only drug in blood samples and had been evaluated by a clinical test for impairment (CTI) performed by a police physician at the time of blood sampling. The impaired drivers had higher blood flunitrazepam concentrations than the not impaired drivers. Multivariate analysis revealed that both blood flunitrazepam concentration and age of the suspected drivers had independent impact on impairment, indicating tolerance with age. Most of the effects measured were sedative effects of flunitrazepam and these effects were related to flunitrazepam level. Possible paradoxical reactions were observed in a subgroup of 23 individuals (6%), but these reactions did not relate to blood flunitrazepam concentration. The suspects of violent crime showed similar degree impairment and had not more paradoxical reactions than the suspected drugged drivers. The findings were in agreement with other research that claims paradoxical reactions should be viewed as a reaction in certain individuals, and does not support the notion that flunitrazepam in high concentration produces aggression in all individuals taking the drug.

The CYP2C19 genotype and the use of oral contraceptives influence the pharmacokinetics of carisoprodol in healthy human subjects

AIMS

The aim of the present study was to investigate if subjects with one normal and one non-functional CYP2C19 allele (intermediate metabolizers; IMs) metabolized carisoprodol differently than individuals with two normal CYP2C19 alleles (extensive metabolizers; EMs) We also wanted to investigate whether the use of oral contraceptives influences the metabolism of carisoprodol in EMs and IMs. Impairing effects on psychomotor coordination and feelings of sedation were studied by comparing IMs with EMs following their ingestion of a single dose of 700 mg carisoprodol.

METHODS

Thirty-seven healthy Caucasian volunteers participated in the study, of whom 25 were not using any drugs known to interact with CYP2C19, including two poor metabolizers (PMs) (CYP2C19 *2/*2 or CYP2C19 *2 /*4), 11 IMs (CYP2C19 *1/*2 or CYP2C19 *1/*4) and 12 EMs (CYP2C19 *1/*1); the remaining 12 participants were six EMs and six IMs using oral contraceptives. A single oral dose of 700 mg of carisoprodol was given, and blood drug concentrations were followed for 11 h and 45 min. During this time period, different pharmacodynamic measurements were made.

RESULTS

IMs had a longer elimination half life (T(1/2)) (127 min; 95% confidence interval (CI) 95, 159) than EMs (96 min; 95% CI 84, 107) and a larger area under the concentration-time curve from 0 to infinity (AUC(0-infinity)) for carisoprodol (16.3 microg h ml(-1) ; 95% CI 11.9, 20.7) than EMs (11.3 microg h ml(-1) ; 95% CI 7.8, 14.8). The use of oral contraceptives was accompanied by larger AUC(0-infinity) for carisoprodol in both EMs (18.5 microg h ml(-1); 95% CI 10.7, 26.3) and IMs (26.0 microg h ml(-1) ; 95% CI 18.8, 33.2). EMs using oral contraceptives also had a longer T(1/2) (117 min; 95% CI 92, 143) and higher maximum carisoprodol concentration than EMs not using oral contraceptives. No significant differences in pharmacodynamic parameters were found between subjects in the different genotype groups or between users and non-users of oral contraceptives.

CONCLUSIONS

Subsequent to a single-dose administration of carisoprodol, the carisoprodol AUC was approximately 45% larger in CYP2C19 IMs than in EMs. The use of oral contraceptives increased the AUC by approximately 60% in both EMs and IMs. Despite these pharmacokinetic effects, no significant differences with respect to the CYP2C19 IM and EM genotypes were observed in the acute impairing effects of a single dose of carisoprodol.

High concentrations of diazepam and nordiazepam in blood of impaired drivers: association with age, gender and spectrum of other drugs present

A zero-concentration limit for controlled scheduled drugs in the blood of motorists was introduced in Sweden in 1999 and the annual number of arrests for driving under the influence of drugs (DUID) has since increased eight-fold. However, for prescription drugs that might cause impairment (e.g. benzodiazepines) additional proof is needed to justify prosecution, such as whether the medication was being misused. Over a 2-year period, we found 94 cases of DUID in which the concentrations of diazepam in blood was 1.1 microg/g or more. Diazepam (D) and nordiazepam (ND) were determined in whole blood by capillary gas chromatography with a limit of quantitation of 0.05 microg/g for each compound. The mean (median) and maximum concentrations of D were 2.0 microg/g (1.7 microg/g) and 7.8 microg/g and the corresponding ND concentrations were 1.5 microg/g (1.0 microg/g) and 7.6 microg/g, respectively. The concentration of D in blood exceeded 2 microg/g in 21% of cases and was over 3.0 microg/g in 11% of cases. D and ND were the only drugs present in eight cases (seven men and one women) and in another five cases ethanol was present at concentrations ranging from 0.81 to 1.98 mg/g. Polydrug use was very common in these DUID suspects and D and ND coexisted with amphetamine in 20% of cases, tetrahydrocannabinol in 18% of cases and with both these illicit drugs in 12% of cases. The next most prevalent drug combination was D, ND and morphine (mostly derived from heroin), seen in 13% of cases. Other psychoactive prescription drugs were identified in blood including alprazolam, flunitrazepam, oxazepam, zolpidem and zopiclone. This case series of DUID suspects demonstrate the high frequency of polydrug use showing preference for illicit drugs like amphetamine, cannabis and heroin, in that order. Furthermore, Swedish traffic delinquents frequently overdose with prescription drugs as exemplified here by unusually high concentrations of D and its active metabolite ND.

Distribution of Diazepam and Nordiazepam Between Plasma and Whole Blood and the Influence of Hematocrit

The binding of drugs to plasma proteins is important to consider when concentrations in whole blood (eg, in forensic toxicology) are compared with therapeutic and toxic concentrations based on the analysis of plasma or serum. The plasma to whole blood distribution of diazepam (D) and its major metabolite nordiazepam (ND) was investigated under in vitro and ex vivo conditions. Studies in vitro were done by spiking whole blood with D and ND to give concentrations ranging from 0.1 to 1.0 microg/g. Venous blood was also obtained from hospital blood donors (n = 66) after informed consent. The hematocrit, hemoglobin, and water content of blood specimens were determined by routine procedures before D and ND were added to produce target concentrations of approximately 0.5 microg/g for each substance. The ex vivo work was done with blood specimens from hospital outpatients who were being medicated with D. Concentrations of D and ND were determined in body fluids by capillary column gas chromatography after adding prazepam as internal standard and solvent extraction with butyl acetate. The method limit of quantitation was 0.03 microg/g for both D and ND. The concentrations of D and ND were highest in plasma and lowest in erythrocytes. The plasma/blood (P/B) distribution ratios did not depend on drug concentration between 0.1 and 1.0 microg/g. The mean P/B ratios were 1.79:1 for D and 1.69:1 for ND when hematocrit was 45%. Furthermore, the P/B ratio for D (y) was positively correlated with blood hematocrit (x) and the regression equation was y = 0.636 + 0.025x (r = 0.86, P < 0.001). A similar strong association was found between the P/B ratio and hematocrit for ND (r = 0.79). P/B ratios of D and ND, blood hematocrit, hemoglobin, and the water content differed between sexes (P < 0.001). The overall mean P/B ratios for D and ND were 1.69 +/- 0.097 (+/- SD) and 1.62 +/- 0.08 (P < 0.001, n = 66) respectively when the mean hematocrit was 42.9 +/- 3.4 (+/- SD). For forensic purposes, it would be better to forgo making any conversion of a drug concentration measured in whole blood to that expected in plasma or serum; instead, therapeutic and toxic concentrations should be established for the actual specimens received.

Impairment due to intake of carisoprodol

BACKGROUND

Carisoprodol is a centrally acting muscle relaxant commonly used for lower back pain. It is a drug of abuse and has been detected among impaired drivers. Carisoprodol's active metabolite meprobamate is thought to act through the GABA(A) receptor complex and produces a well-known impairing effect. It is unclear whether therapeutic intake of carisoprodol leads to impairment, and the effect of supratherapeutic doses has not been investigated. Possible impairment could further be a product of the parent drug and/or the metabolite meprobamate. The present study aimed to investigate if carisoprodol had an impairing effect by it self.

METHODS

From the database at the Norwegian Institute of Public Health, Division for Forensic Toxicology and Drug Abuse 62 cases containing carisoprodol and meprobamate as only drugs were identified. These cases constituted our material.

RESULTS

Impaired drivers (73%) had higher blood carisoprodol concentration than not impaired drivers (27%), but no difference in blood meprobamate concentration was found for all the drivers viewed together. Amongst occasional users of carisoprodol, however, there was difference in blood meprobamate concentration between not impaired and impaired drivers. The risk of being judged impaired rose with increasing blood carisoprodol concentration, but not with increasing blood meprobamate concentration. The clinical effects of carisoprodol as measured by the clinical test for impairment (CTI) resembled those of benzodiazepines with some important differences such as tachycardia, involuntary movements, hand tremor and horizontal gaze nystagmus, which may be specific carisoprodol effects.

CONCLUSION

Carisoprodol probably has an impairing effect by itself, at least at blood concentration levels above which can be seen after therapeutic intake of the drug.