Psychoactive substances in seriously injured drivers in Denmark.

This study assesses the presence of a number of psychoactive substances, including alcohol, based on blood samples from 840 seriously injured drivers admitted to five selected hospitals located in five different regions of Denmark. The study was a part of the EU 6th framework program DRUID (Driving Under the Influence of Drugs, Alcohol and Medicines). Blood samples were screened for 30 illegal and legal psychoactive substances and metabolites as well as ethanol. Danish legal limits were used to evaluate the frequency of drivers violating the Danish legislation while limit of quantification (LOQ) was used for monitoring positive drivers. Tramadol is not included in the Danish legislation therefore the general cut off, as decided in the DRUID project was used. Overall, ethanol (18%) was the most frequently identified compound (alone or in combination with other drugs) exceeding the legal limit, which is 0.53g/l in Denmark. The percentage of seriously injured drivers testing positive for medicinal drugs at levels above the Danish legal limit was 6.8%. Benzodiazepines and Z-drugs (6.4%) comprised the majority of this group. One or more illegal drugs (primarily amphetamines and cannabis) were found to be above the Danish legal limit in 4.9% of injured drivers. Young men (median age 31 years) were over-represented among injured drivers who violated Danish law for alcohol and drugs. Diazepam (4.4%), tramadol (3.2%), and clonazepam (3.0%) were the medicinal drugs most frequently detected at levels above LOQ, whereas amphetamines (5.4%) (amphetamine [5.2%] and methamphetamine [1.5%]), tetrahydrocannabinol (3.7%), and cocaine (3.3%), including the metabolite benzoylecgonine, were the most frequently detected illegal drugs. A driver could be positive for more than one substance; therefore, percentages are not mutually exclusive. Poly-drug use was observed in 112 (13%) seriously injured drivers. Tramadol was detected above DRUID cutoffs in 2.1% of seriously injured drivers. This is 3.5 times that observed in a Danish survey of randomly selected drivers. Moreover, illegal and medicinal drug levels above the Danish legal limit were present more than 10 times as frequently as in injured drivers, whereas ethanol was present more than 30 times as frequently than in randomly selected drivers. The results indicate that there is an increased risk in traffic when driving under the influence of psychoactive drugs, especially alcohol in young male drivers.

Presence of psychoactive substances in oral fluid from randomly selected drivers in Denmark.

This roadside study is the Danish part of the EU-project DRUID (Driving under the Influence of Drugs, Alcohol, and Medicines) and included three representative regions in Denmark. Oral fluid samples (n=3002) were collected randomly from drivers using a sampling scheme stratified by time, season, and road type. The oral fluid samples were screened for 29 illegal and legal psychoactive substances and metabolites as well as ethanol. Fourteen (0.5%) drivers were positive for ethanol (alone or in combination with drugs) at concentrations above 0.53g/l, which is the Danish legal limit. The percentage of drivers positive for medicinal drugs above the Danish legal concentration limit was 0.4%; while, 0.3% of the drivers tested positive for one or more illicit drug at concentrations exceeding the Danish legal limit. Tetrahydrocannabinol, cocaine, and amphetamine were the most frequent illicit drugs detected above the limit of quantitation (LOQ); while, codeine, tramadol, zopiclone, and benzodiazepines were the most frequent legal drugs. Middle aged men (median age 47.5 years) dominated the drunk driving group, while the drivers positive for illegal drugs consisted mainly of young men (median age 26 years). Middle aged women (median age 44.5 years) often tested positive for benzodiazepines at concentrations exceeding the legal limits. Interestingly, 0.6% of drivers tested positive for tramadol, at concentrations above the DRUID cut off; although, tramadol is not included in the Danish list of narcotic drugs. It can be concluded that driving under the influence of drugs is as serious a road safety problem as drunk driving.

Drugs in injured drivers in Denmark.

As part of the project Impaired Motorists, Methods of Roadside Testing and Assessment for Licensing (IMMORTAL) under the European Commission's Transport RTD Programme of the 5th Framework Programme [I.M. Bernhoft, Drugs in accidents involved drivers in Denmark, D-R4.3 of the project Impaired Motorists, Methods Of Roadside Testing and Assessment for Licensing (IMMORTAL), , 2005], a study regarding drugs in accident-involved drivers was carried out in Denmark. The main objectives of this study were: (1) to collect and analyse samples from injured drivers for the presence of drugs; (2) to give an indication whether drugs may have contributed to traffic accidents; and (3) to get information on the drug-positive drivers and their drug use. This paper focuses on objective 1. Injured drivers who were treated in hospital were asked to give a saliva sample, a blood sample or both. The samples were screened for the following substances: opiates, amphetamines, methamphetamines, incl. MDMA (ecstasy), cannabinoids and metabolites, cocaine and metabolites and benzodiazepines. Screenings were carried out by means of Cozart Microplate EIA kit. Positive screenings were confirmation analysed by gas chromatography-mass spectrometry (GC-MS) or liquid chromatography/tandem mass spectrometry (LC/MS/MS). In total, 26 out of 330 patients were confirmed positive for one or more of the six drug groups. However, three patients were excluded from the survey for various reasons. Of the remaining 23 drug-positive patients 15 were found positive for one drug group, and in five of these cases alcohol was present in a concentration over the legal limit in Denmark (0.05%). The other eight patients were found positive for two drug groups, and in four of these cases, alcohol was also present in a concentration over the legal limit. Alcohol was found both in combinations with medicinal drugs, with illegal drugs and with both. Based on the saliva or blood concentrations, we estimate that there is a strong suspicion of impairment in 9 out of 23 cases, and in another six cases it was likely that the drivers were impaired.

Effect of lowering the alcohol limit in Denmark.

On 1 March 1998, the Danish per se limit was lowered from 0.08 to 0.05% blood alcohol concentration (BAC) for motor vehicle drivers. Based on accident data and drivers' drinking habits before and after the amendment, the effect of the new limit has been evaluated. Interviews revealed a significant decrease in the number of drinks that drivers allow themselves to drink within a 2-h period before driving. The proportion of drivers, who would not drink at all or only have one drink, increased from 71% before the amendment to 80% after the amendment. Drivers with changed drinking habits most often stated the lower limit as the main reason for having less alcohol. However, based on accident data from the first year after the amendment, this has not resulted in a marked decrease in the proportion of injury accidents with impaired motor vehicle drivers (BAC>/=0.05%) compared to all injury accidents. On the contrary, the proportion of fatal accidents with drink-drivers compared to all fatal accidents has increased in the after-period. The total number of drink-driving sentences were a little larger in 1999 than in 1997 because of the lower limit, but a significant change from higher towards lower alcohol levels can be seen.