Concentrations of scheduled prescription drugs in blood of impaired drivers: considerations for interpreting the results

The Appearance, Taste, and Concentrations of Zolpidem Dissolved in Still Water and Carbonated Beverages

Zolpidem is a sedative that could be used to drug victims, but its suitability to dissolve in drinks is unknown. In this small study, we added either crushed or whole tablets of zolpidem hemitartrate to carbonated beverages or still water to observe how this affected the taste and appearance. Also, concentrations were measured by ultra-high performance liquid chromatography tandem mass spectrometry at different time intervals. Two crushed tablets (20 mg) in cider (250 mL) lead to a maximum concentration of 84 mg/L zolpidem base after 30 min, while the corresponding concentration after adding fifteen tablets (150 mg) was 467 mg/L. There was little change in taste, but froth and turbidity were observed when adding high doses to carbonated beverages. Carbonated beverages spiked with 20 mg of crushed zolpidem hemitartrate tablets reached concentrations that could cause impairment. Spiking with 150 mg could possibly be lethal if several mouthfuls were ingested.

First derivative spectrofluorimetric determination of zopiclone and its degradation product, 2-amino-5-chloropyridine, in pharmaceutical formulations with preliminary tool in biological fluids for clinical evidence of zopiclone intake

A simple, fast, sensitive and stability-indicating derivative spectrofluorimetric method is presented for the assay of zopiclone (ZOP), a drug with hypnotic effect, and its main degradation product and major contaminant, 2-amino-5-chloropyridine (ACP). The method is based on measuring the inherent fluorescence intensity of both drugs at λex=300nm in methanol, then differentiation using D1 (first derivative technique). The developed method was found to be rectilinear over a range of 0.2-4μg/mL of ZOP and 4-100ng/mL of ACP. The limits of detection were 0.05μg/mL of ZOP and 0.2ng/mL of ACP with the limit of quantitation of 0.17μg/mL of ZOP and 0.7ng/mL of ACP. The outcoming results of the proposed method were compared to those obtained by a reference method showing no significant statistical difference between them concerning precision and accuracy. Additionally, the developed method was applied for detecting ACP in spiked human urine and plasma specimens as a tool of clinical evidence of zopiclone intake that can be easily implemented in forensic laboratories. The proposed method was validated as per ICH guidelines.

Detection of 4 benzodiazepines in oral fluid as biomarker for presence in blood

BACKGROUND

Analysis of samples of oral fluid (mixed saliva) is increasingly being used to detect recent drug use. The aim of this investigation was to assess the suitability of testing oral fluid as a biomarker for the presence of 4 benzodiazepines in blood and its possible application in clinical settings and in research on drug use.

METHODS

Paired samples of oral fluid and blood from 4080 individuals in 4 European countries were collected and analyzed for benzodiazepines using gas or liquid chromatography with mass spectroscopic detection.

RESULTS

Concentration data for the 4 most commonly detected benzodiazepines were studied: alprazolam, clonazepam, diazepam, and nordiazepam. Large variations in oral fluid to blood concentration ratios were observed for the studied benzodiazepines. The interquartile ranges for the oral fluid to blood concentrations ratios corresponded to 88%-197% of the median values. Selecting cutoff concentrations in oral fluid that gave the best accuracy in identifying individuals with benzodiazepine concentrations in blood above chosen thresholds produced accuracies of 74%-85% and the fraction of false negatives was 9%-23%.

CONCLUSIONS

The concentration of the 4 studied benzodiazepines in oral fluid can neither be used to accurately estimate the concentrations in blood nor to correctly identify patients with blood drug concentrations below or above recommended therapeutic levels. When using analytical methods with limits of quantitation corresponding to concentrations less than 0.5 ng/mL in undiluted oral fluid, it may be used to confirm a recent intake of benzodiazepines. However, it is likely that some false negatives may occur.

Comparing drug detection in oral fluid and blood: data from a national sample of nighttime drivers

OBJECTIVE

The National Roadside Survey is a study undertaken in the United States to determine the prevalence of alcohol and drugs in randomly selected drivers. Following the success of a 2006 pilot study, the 2007 survey incorporated, for the first time, the collection of biological specimens for drug analysis. This article compares the results obtained from blinded analyses of pairs of oral fluid and blood samples obtained from the same subject.

METHODS

During the 2007 survey, more than 7000 nighttime drivers were randomly stopped and surveyed for their self-reported drug use and were requested to donate an oral fluid specimen using the Quantisal (Immunalysis Corporation, Pomona, CA) device and a blood sample. Overall, 5869 oral fluid specimens were collected from nighttime drivers with 3236 corresponding blood samples.

RESULTS

Biological specimens were analyzed for a wide range of drugs. At nighttime, 14.4 percent of the drivers were positive for drugs in oral fluid, with just over half of those having marijuana present (7.6%). Of the 3236 pairs of specimens, 2676 were negative for all drugs, and 326 matched pairs of samples were both positive, out of which 247 (75.8%) were an exact match for all drug classes and 70 (21.5%) were positive for at least one common drug class.

CONCLUSIONS

Oral fluid and blood samples provided very similar information regarding recent drug intake by randomly tested drivers and oral fluid yielded a higher detection rate for one drug (cocaine) than blood. Oral fluid can be considered a reliable alternative to blood as a matrix for drug testing.

Mechanisms of zolpidem-induced long QT syndrome: acute inhibition of recombinant hERG K(+) channels and action potential prolongation in human cardiomyocytes derived from induced pluripotent stem cells

BACKGROUND AND PURPOSE

Zolpidem, a short-acting hypnotic drug prescribed to treat insomnia, has been clinically associated with acquired long QT syndrome (LQTS) and torsade de pointes (TdP) tachyarrhythmia. LQTS is primarily attributed to reduction of cardiac human ether-a-go-go-related gene (hERG)/I(Kr) currents. We hypothesized that zolpidem prolongs the cardiac action potential through inhibition of hERG K(+) channels.

EXPERIMENTAL APPROACH

Two-electrode voltage clamp and whole-cell patch clamp electrophysiology was used to record hERG currents from Xenopus oocytes and from HEK 293 cells. In addition, hERG protein trafficking was evaluated in HEK 293 cells by Western blot analysis, and action potential duration (APD) was assessed in human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes.

KEY RESULTS

Zolpidem caused acute hERG channel blockade in oocytes (IC(50) = 61.5 μM) and in HEK 293 cells (IC(50) = 65.5 μM). Mutation of residues Y652 and F656 attenuated hERG inhibition, suggesting drug binding to a receptor site inside the channel pore. Channels were blocked in open and inactivated states in a voltage- and frequency-independent manner. Zolpidem accelerated hERG channel inactivation but did not affect I-V relationships of steady-state activation and inactivation. In contrast to the majority of hERG inhibitors, hERG cell surface trafficking was not impaired by zolpidem. Finally, acute zolpidem exposure resulted in APD prolongation in hiPSC-derived cardiomyocytes.

CONCLUSIONS AND IMPLICATIONS

Zolpidem inhibits cardiac hERG K(+) channels. Despite a relatively low affinity of zolpidem to hERG channels, APD prolongation may lead to acquired LQTS and TdP in cases of reduced repolarization reserve or zolpidem overdose.

Middle-of-the-night hypnotic use in a large national health plan

STUDY OBJECTIVES

Although difficulty maintaining sleep (DMS) is the most common nighttime insomnia symptom among US adults, many FDA-approved hypnotics have indications only for sleep onset, stipulating bedtime administration to offset residual sedation. Given the well-known self-medication tendencies of insomniacs, concern arises that maintenance insomniacs might be prone to self-administer their prescribed hypnotics middle-of-the-night (MOTN) after nocturnal awakenings, despite little efficacy-safety data supporting such use. However, no US data characterize the actual population prevalence or correlates of MOTN hypnotic use.

METHODS

Telephone interviews assessed patterns of prescription hypnotic use in a national sample of 1,927 commercial health plan members (ages 18-64) receiving prescription hypnotics within 12 months of study. The Brief Insomnia Questionnaire assessed insomnia symptoms.

RESULTS

20.2% of respondents reported MOTN hypnotic use, including 9.0% who sometimes used twice-per-night (once at bedtime plus once MOTN) and another 11.2% who sometimes used MOTN, but never twice-per-night. The remaining 79.8% used exclusively at bedtime. Among exclusive MOTN users, only 14.0% used MOTN on the advice of their physician (52.6% of those seen by sleep medicine specialists and 42.6% by psychiatrists vs. 5.2% to 13.6% seen by other physicians). MOTN use predictors included DMS being the most bothersome sleep problem, long duration of hypnotic use, and low frequency of DMS.

CONCLUSIONS

One-fifth of patients with prescription hypnotics used MOTN, only a minority on advice from their physicians. Since significant next-day cognitive and psychomotor impairment is documented with off-label MOTN hypnotic use, prescribing physicians should question patients about unsupervised MOTN dosing.

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.

Comparison of drug concentrations measured in roadside surveys and in seriously injured drivers in Belgium

The objective of this paper is to compare concentrations of alcohol, illicit, and medicinal drugs in seriously injured drivers and drivers selected randomly at the roadside. Blood samples were analyzed for alcohol, 17 medicinal drugs and 8 illicit psychoactive substances and/or their metabolites by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography mass spectrometry (GC-MS) in injured drivers admitted to the emergency departments of five hospitals in Belgium between January 2008 and May 2010 and in drivers randomly selected between January 2008 and September 2009. Three hundred and seventy-seven seriously injured drivers and 2750 roadside respondents were selected. In the roadside survey, out of the 203 concentrations above DRUID (Driving Under the Influence of Drugs, Alcohol and Medicines) cut-offs for medicinal drugs, 51% were in the therapeutic range, 46% infratherapeutic, and 2.5% supratherapeutic. In the seriously injured drivers, out of the 78 concentrations above DRUID cut-offs for medicinal drugs, these percentages were respectively 63%, 33%, and 4%. Significant differences were found in the distribution of concentrations for opioids, benzodiazepines, and Z-drugs. For the latter, while in the seriously injured drivers study most concentrations were therapeutic, in the roadside survey most were infratherapeutic. The opposite was observed for the opioids. Eight and 41% of the roadside respondents and injured drivers, respectively, had an alcohol concentration above 0.1 g/L, with higher concentrations found in the injured drivers. For illicit drugs, significant differences were found for amphetamine and cocaine, for which respectively lower and higher concentrations were observed in the blood samples taken in the roadside survey.

Toxicogenetics--cytochrome P450 microarray analysis in forensic cases focusing on morphine/codeine and diazepam

Genetic polymorphisms in cytochrome P 450 (CYP) enzymes could lead to a phenotype with altered enzyme activity. In pharmacotherapy, genotype-based dose recommendations achieved great importance for several drugs. In our pilot study, we ask if these genetic tests should be applied to forensic problems as a matter of routine. Starting from 2004 through 2008, we screened routine cases for samples where the relation of parent compound to metabolite(s) (P/M ratio), particularly morphine to codeine ratios and diazepam to its metabolites, was noticeable or not consistent with the information provided by the defendants. We found 11 samples with conspicuous results. These were analyzed for polymorphisms of the CYP 2D6 and 2C19 genes using the Roche AmpliChip Cytochrome P450 Genotyping test. If not previously conducted, a general unknown analysis by gas chromatography/mass spectrometry (GC/MS) was additionally carried out. For CYP 2D6, we found two cases with the genotype poor metabolizer (PM), three cases with heterozygote extensive metabolizer genotype classified as an intermediate metabolizer (IM) with probably reduced enzyme activities, but no ultrarapid metabolizer genotype. For CYP 2C19, two cases were characterized as IM phenotypes, with no PM found. Once we achieved no appropriate amounts of DNA, one case was excluded after GC/MS analysis. Only in one case could the polymorphism clearly explain the changes in drug metabolism. More frequently, a drug-drug interaction was thought to have a stronger impact. Additionally, our results suggest that IM genotypes may be more relevant than previously suspected. With respect to the small number of cases in which we thought a genotyping would be helpful, we conclude that the overall relevance of toxicogenetics in forensic problems is moderate. However, in some individual cases, a genotyping may provide new insight.

Effects of d-amphetamine on simulated driving performance before and after sleep deprivation

RATIONALE

Stimulant drugs are commonly abused and also used to promote wakefulness, yet their effects on driving performance during sleep deprivation have not been thoroughly researched in experimental studies.

OBJECTIVES

The aims were to assess the effects on fundamental driving parameters during simulated driving of two doses of d-amphetamine and further to assess the interaction between d-amphetamine and sleep deprivation.

METHODS

A double-blind, placebo-controlled experiment including 18 healthy male volunteers was conducted.

RESULTS

The participants felt more alert when taking a dose of d-amphetamine than when taking placebo, and the effect was stronger for the higher dose. However, the data did not show any evidence that taking d-amphetamine prevented the subjects from becoming successively sleepier during the night. A significant main effect of the dose was found for three out of the five primary indicators where the lower dose led to improved driving. These indicators were crossing-car reaction time, and coherence and delay from a car-following event. Regarding sleep deprivation, a main effect was found for four of the primary indicators and three of the secondary indicators. The results showed overall impaired driving with respect to standard deviation of lateral position and delay in reaction time when the sleep-deprived conditions were compared to the alert condition. We found no interactions between dose and sleep deprivation for any of the performance indicators.

CONCLUSIONS

Our results suggest that administration of d-amphetamine does not compensate for impairment of driving due to fatigue. The positive effects of 10 mg were not further improved or even sustained when increasing the dose to 40 mg.

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.

What non-alcohol drugs are used by drinking drivers in Sweden? Toxicological results from ten years of forensic blood samples

INTRODUCTION AND METHOD

Using a forensic toxicology database (TOXBASE), the toxicological results from 10 years of forensic blood samples from people arrested for driving under the influence of alcohol and/or other drugs were reviewed.

RESULTS

Alcohol was the only drug identified in blood in N=35,704 cases at a median blood-alcohol concentration (BAC) of 1.63 mg/g. The mean age (±SD) of these offenders was 40±15years and 89% were male. The median BAC was lower (1.30 mg/g) in drivers who had consumed alcohol and used a prescription drug before driving (N=1,251). The mean age of this group of traffic offenders was 38±13years and 85% were male. Both the median BAC (0.97 mg/g) and the mean age were lowest (36±11years, 92% male) in N=3,153 drivers who had consumed alcohol and used illicit drugs before driving. Cannabis, amphetamine, cocaine and morphine (metabolite of heroin) were the commonest illicit drugs identified in blood samples. Sedative-hypnotics (benzodiazepines) were the major prescription drugs co-ingested with alcohol. Poly-drug use was a common finding in these traffic delinquents, although individuals who only drank alcohol had a higher median BAC and were also several years older than drinking drivers combining alcohol with other drugs before driving.

IMPACT ON INDUSTRY

Zero-tolerance legislation did not deter hard-core offenders. In future there should be more focus on treatment for alcohol and substance abuse disorder rather than conventional punishments for this type of traffic crime.

Zolpidem ingestion, automatisms, and sleep driving: a clinical and legal case series

STUDY OBJECTIVES

To describe zolpidem-associated complex behaviors, including both daytime automatisms and sleep-related parasomnias.

METHODS

A case series of eight clinical patients and six legal defendants is presented. Patients presented to the author after an episode of confusion, amnesia, or somnambulism. Legal defendants were being prosecuted for driving under the influence, and the author reviewed the cases as expert witness for the defense. Potential predisposing factors including comorbidities, social situation, physician instruction, concomitant medications, and patterns of medication management were considered.

RESULTS

Patients and defendants exhibited abnormal behavior characterized by poor motor control and confusion. Although remaining apparently interactive with the environment, all reported amnesia for 3 to 5 hours. In some cases, the episodes began during daytime wakefulness because of accidental or purposeful ingestion of the zolpidem and are considered automatisms. Other cases began after ingestion of zolpidem at the time of going to bed and are considered parasomnias. Risk factors for both wake and sleep-related automatic complex behaviors include the concomitant ingestion of other sedating drugs, a higher dose of zolpidem, a history of parasomnia, ingestion at times other than bedtime or when sleep is unlikely, poor management of pill bottles, and living alone. In addition, similar size and shape of two medications contributed to accidental ingestion in at least one case.

CONCLUSIONS

Sleep driving and other complex behaviors can occur after zolpidem ingestion. Physicians should assess patients for potential risk factors and inquire about parasomnias. Serious legal and medical complications can occur as a result of these forms of automatic complex behaviors.

Zolpidem for insomnia

INTRODUCTION

The imidazopyridine derivative zolpidem , which acts as a benzodiazepine (BZ) receptor agonist, is the most widely prescribed hypnotic drug in the US.

AREAS COVERED

This review addresses the neuroreceptor properties of zolpidem; clinical pharmacokinetics, pharmacodynamics and drug interactions; efficacy as a hypnotic; adverse effects; tolerance, dependence and withdrawal; relation to motor vehicle accidents and complex sleep behaviors; and new dosage forms.

EXPERT OPINION

Approved doses of zolpidem (10 mg for adults, 5 mg for the elderly) are consistently effective in reducing sleep latency and consequently increasing sleep duration in patients with insomnia. However, favorable effects on sleep maintenance are observed less consistently. Residual daytime effects are unlikely with recommended doses, and provided that at least 8 h elapse prior to arising. Hypnotic efficacy is maintained with repeated nightly use, and the risk of rebound insomnia is low. Dependence and abuse of zolpidem are no more likely to occur than with typical benzodiazepines. Newly available novel dosage forms of zolpidem have increased therapeutic options for patients with insomnia variants such as sleep maintenance insomnia and middle-of-the-night awakening.

Phenazepam abuse in Finland: findings from apprehended drivers, post-mortem cases and police confiscations

Phenazepam is a long-acting benzodiazepine that, unlike other benzodiazepines, is currently not scheduled as a narcotic in Finland, most other European countries or the USA. It is used as an anxiolytic, sedative-hypnotic and anti-epileptic, mainly in Russia. In Finland, as well as in some other countries, an increase in the unauthorized use of phenazepam has been observed in recent years. In the one year period between July 1, 2010 and June 30, 2011 the prevalence of phenazepam in Finland was assessed among drivers apprehended for driving under the influence of drugs (DUID), in medico-legal autopsy cases and in police confiscations of illicit drugs. In DUID cases an LC-MS/MS method preceded by solid phase extraction was used for the determination of phenazepam. In the post-mortem investigations the sample preparation consisted of liquid-liquid extraction followed by derivatization and the determination was carried out by GC-MS. The police confiscations were analysed by GC-MS. There were 141 positive phenazepam cases among apprehended drivers, representing approximately 3.5% of all confirmed drug cases (n=4007) in this time period. The median (range) phenazepam blood concentration in DUID cases was 0.061 mg/L (0.004-3.600 mg/L). The median phenazepam concentration in cases with no concomitant stimulant use was significantly higher than the overall median concentration. Phenazepam was found in 17 medico-legal autopsy cases and the median (range) blood concentration was 0.048 mg/L (0.007-1.600 mg/L). Phenazepam was not considered by the medico-legal team to be the sole cause of death in any of the cases, the majority of them being accidental opiod overdoses. There were 26 seizures of phenazepam by the Police in the time period studied, some of the batches consisted of a mixture of phenazepam and stimulant designer drugs. The data show that phenazepam abuse is a widespread phenomenon in Finland. A typical user was a male multi-drug user in his 30s. The concentration range of phenazepam among apprehended drivers and medico-legal autopsy cases was wide and the drug was usually found along with other psychoactive drugs. Therefore, although it seems likely that phenazepam contributed to impairment of driving in some DUID cases, the extent of its effect remains unclear and further studies are needed to define the concentrations causing impairment and toxicity.

The need for drugged driving per se laws: a commentary

OBJECTIVE

Triggered by the new federal commitment announced by the Office of National Drug Control Policy (ONCDP) to encourage states to enact drugged driving per se laws, this article reviews the reasons to establish such laws and the issues that may arise when trying to enforce them.

METHODS

A review of the state of drunk driving per se laws and their implications for drugged driving is presented, with a review of impaired driving enforcement procedures and drug testing technology.

RESULTS

Currently, enforcement of drugged driving laws is an adjunct to the enforcement of laws regarding alcohol impairment. Drivers are apprehended when showing signs of alcohol intoxication and only in the relatively few cases where the blood alcohol concentration of the arrested driver does not account for the observed behavior is the possibility of drug impairment pursued. In most states, the term impaired driving covers both alcohol and drug impairment; thus, driver conviction records may not distinguish between the two different sources of impairment. As a result, enforcement statistics do not reflect the prevalence of drugged driving.

CONCLUSIONS

Based on the analysis presented, this article recommends a number of steps that can be taken to evaluate current drugged driving enforcement procedures and to move toward the enactment of drug per se laws.

The frequency of drugs among Danish drivers before and after the introduction of fixed concentration limits

OBJECTIVE

Until July 2007, the driving under the influence of drugs (DUID) legislation in Denmark was based on impairment, evaluated on the basis of a clinical investigation and toxicological analyses, but in 2007 fixed concentration limits were introduced into the Danish traffic legislation. The objective for this study was to investigate the prevalence of medication and illicit drugs among Danish drivers before and after 2007.

METHODS

Blood samples from drivers suspected of being under the influence of medication and/or illicit drugs were investigated as requested by the police. The results for a 10-year period before and for one year after the introduction of fixed concentration limits are presented.

RESULTS

A total of 2340 blood samples were analyzed for the presence of medications and/or illicit drugs for the period 1997-2006. The average number of cases per year was 234 (213-283), and on average 87 percent of the investigated cases were positive for one or more drugs. For 2008 the number of investigated traffic cases was increased to 1176. Seventy-three percent of the cases from 2008 were positive for one or more drugs. Benzodiazepines, cannabis (THC), amphetamine, heroin/morphine, methadone, cocaine, and ecstasy were the most frequently detected drugs for the period 1997-2006 and also in 2008. The number of these cases in which an ethanol level was detected above 0.5 mg/g (the Danish legal limit) was on average 18 percent (9-26%) for the period 1997-2006 and 19 percent for 2008. The average age of the drivers ranged from 31 to 34 years for the period 1997-2006 and was 31 years for 2008. The percentage of females per year ranged from 3 to 20 percent.

CONCLUSION

The number of traffic cases investigated for substances other than ethanol were consistently low, in the range of 200 to 300 per year during the period from 1997 to 2006, but after the introduction of fixed concentration limits in 2007 a 5-fold increase was seen already in 2008.

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.

First nationwide study on driving under the influence of drugs in Switzerland

In Switzerland, a two-tier system based on impairment by any psychoactive substances which affect the capacity to drive safely and zero tolerance for certain illicit drugs came into force on 1 January 2005. According to the new legislation, the offender is sanctioned if Delta(9)-tetrahydrocannabinol THC is >or=1.5ng/ml or amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), cocaine, free morphine are >or=15ng/ml in whole blood (confidence interval+/-30%). For all other psychoactive substances, impairment must be proven in applying the so-called "three pillars expertise". At the same time the legal blood alcohol concentration (BAC) limit for driving was lowered from 0.80 to 0.50g/kg. The purpose of this study was to analyze the prevalence of drugs in the first year after the introduction of the revision of the Swiss Traffic Law in the population of drivers suspected of driving under the influence of drugs (DUID). A database was developed to collect the data from all DUID cases submitted by the police or the Justice to the eight Swiss authorized laboratories between January and December 2005. Data collected were anonymous and included the age, gender, date and time of the event, the type of vehicle, the circumstances, the sampling time and the results of all the performed toxicological analyses. The focus was explicitly on DUID; cases of drivers who were suspected to be under the influence of ethanol only were not considered. The final study population included 4794 DUID offenders (4243 males, 543 females). The mean age of all drivers was 31+/-12 years (range 14-92 years). One or more psychoactive drugs were detected in 89% of all analyzed blood samples. In 11% (N=530) of the samples, neither alcohol nor drugs were present. The most frequently encountered drugs in whole blood were cannabinoids (48% of total number of cases), ethanol (35%), cocaine (25%), opiates (10%), amphetamines (7%), benzodiazepines (6%) and methadone (5%). Other medicinal drugs such as antidepressants and benzodiazepine-like were detected less frequently. Poly-drug use was prevalent but it may be underestimated because the laboratories do not always analyze all drugs in a blood sample. This first Swiss study points out that DUID is a serious problem on the roads in Switzerland. Further investigations will show if this situation has changed in the following years.

Concentrations of cocaine and its major metabolite benzoylecgonine in blood samples from apprehended drivers in Sweden

Cocaine and its major metabolite benzoylecgonine (BZE) were determined in blood samples from people arrested in Sweden for driving under the influence of drugs (DUID) over a 5-year period (2000-2004). Venous blood or urine if available, was subjected to a broad toxicological screening analysis for cannabis, cocaine metabolite, amphetamines, opiates and the major benzodiazepines. Verification and quantitative analysis of cocaine and BZE in blood was done by gas chromatography-mass spectrometry (GC-MS) at limits of quantitation (LOQ) of 0.02mg/L for both substances. Over the study period 26,567 blood samples were analyzed and cocaine and/or BZE were verified in 795 cases (3%). The motorists using cocaine were predominantly men (>96%) with an average age of 28.3+/-7.1 years (+/-standard deviation, S.D.). The concentration of cocaine was below LOQ in 574 cases although BZE was determined at mean, median and highest concentrations of 0.19mg/L, 0.12mg/L and 1.3mg/L, respectively. In 221 cases, cocaine and BZE were together in the blood samples at mean and (median) concentrations of 0.076mg/L (0.05mg/L) and 0.859mg/L (0.70mg/L), respectively. The concentrations of BZE were always higher than the parent drug; mean BZE/cocaine ratio 14.2 (median 10.9) range 1-55. Cocaine and BZE were the only psychoactive substances reported in N=61 cases at mean (median) and highest concentrations of 0.095 (0.07) and 0.5mg/L for cocaine and 1.01 (0.70) and 3.1mg/L for BZE. Typical signs of drug influence noted by the arresting police officers included bloodshot and glossy eyes, agitation, difficulty in sitting still and incoherent speech.