Prevalence of driving with blood drug concentrations above proposed new legal limits in Norway: Estimations based on drug concentrations in oral fluid

Establishing legal limits for driving under the influence of marijuana

Marijuana has become the most commonly detected non-alcohol substance among drivers in the United States and Europe. Use of marijuana has been shown to impair driving performance and increase crash risk. Due to the lack of standardization in assessing marijuana-induced impairment and limitations of zero tolerance legislation, more jurisdictions are adopting per se laws by specifying a legal limit of Δ9-tetrahydrocannabinol (THC) at or above which drivers are prosecuted for driving under the influence of marijuana. This review examines major considerations when developing these threshold THC concentrations and specifics of legal THC limits for drivers adopted by different jurisdictions in the United States and other countries.

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

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

Prevalence of alcohol and other drugs and the concentrations in blood of drivers killed in road traffic crashes in Sweden

BACKGROUND

Drunk or drug-impaired drivers represent a major public health and societal problem worldwide. Because over 95% of drivers killed on the roads in Sweden are autopsied, reliable information is available about the use of alcohol and/or other drug before the crash.

METHODS

This retrospective 4-year study (2008-2011) used a forensic toxicology database (TOXBASE) to evaluate the concentrations of alcohol and other drugs in blood samples from drivers killed in road-traffic crashes.

RESULTS

The mean age of all victims (N = 895) was 48 ± 20 years, and the majority were male (86%). In 504 drivers (56%), the results of toxicological analysis were negative and these victims were older; mean age (± SD) 47 ± 20 years, than alcohol positive cases (35 ± 14 years) and illicit drug users (34 ± 15 years). In 21% of fatalities, blood-alcohol concentration (BAC) was above the statutory limit for driving (0.2 g/L), although the median BAC was appreciably higher (1.72 g/L). Illicit drugs (mainly amphetamine and cannabis) were identified in ~7% of victims, either alone (2.5%), together with alcohol (1.8%) or a prescription drug (2%). The psychoactive prescription drugs identified were mainly benzodiazepines, z-hypnotics and tramadol, which were found in the blood of 7.6% of crash victims.

CONCLUSIONS

The high median BAC in fatally-injured drivers speaks strongly towards alcohol-induced impairment as being responsible for the crash. Compared with alcohol, the prevalence of illicit and psychoactive prescription drugs was fairly low despite a dramatic increase in the number of drug-impaired drivers arrested by the police after a zero-tolerance law was introduced in 1999.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Phenazepam abuse in the UK: an emerging problem causing serious adverse health problems, including death

OBJECTIVE

Phenazepam (fenazepam; 7-bromo-5-(2-chlorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one; PNZ, 'Bonsai') is a benzodiazepine developed in the former Soviet Union during the 1970s to treat neurological disorders, epilepsy, and alcohol withdrawal syndrome. Its recreational use appears to have increased over recent years. Because of the lack of accessible data on this substance, it is important that information is made available to health professionals.

METHODS

A literature search was conducted in relevant databases (Medline, Toxbase, PsychInfo, etc.), grey literature (using Google Scholar) and Internet sites to identify key data on phenazepam, including epidemiology such as availability, price, supply sources, confiscations, and health-related problems.

RESULTS

Information from these sources indicates the potential for serious adverse health consequences for this drug when taken recreationally and that its use is spreading in the USA and Europe. Although first use was reported in the UK in October 2009, major concerns in the UK arose in summer 2010 when individuals across Britain were admitted to hospital following overdose. Nine UK fatalities were reported in which phenazepam was detected in post mortem toxicology but not implicated in death. The first UK death directly involving phenazepam was notified in July and the second in November 2011.

CONCLUSIONS

This paper summarises the key information about phenazepam abuse and health problems of which health professionals, especially those in Emergency Departments, should be aware and presents new information in respect of fatalities caused by the drug.