Biomarkører i rusmiddelfeltet

Biomarkørene som brukes i rusmiddelfeltet kan deles i tre hovedtyper: . Virkningsmarkører, 2. Inntaksmarkører og 3. Disposisjonsmarkører. Den siste gruppen omtales også som ”trait-markers” og har så langt funnet liten anvendelse i Norge. Virkningsmarkører benyttes så langt for alkohol og uttrykker en biologisk virkning av alkoholkonsumet. De tre viktigste er MCV, GGT og CDT. Ingen av disse er spesifikke for alkoholinntak. MCV er minst sensitiv for alkoholinntak, mens CDT er mest sensistiv, men alle tre markørene fremviser betydelig individuell variasjon mht. respons på konsum. En endret verdi vil vedvare lengst for MCV, kortest for CDT etter totalavhold. Inntaksmarkører utgjøres av påvisningen av et rusmiddel eller dets metabolitter i en biofase, særlig blod, saliva, urin eller hår. Uomdannet alkohol måles lett i de tre første av disse biofasene, med kort tidsvindu etter inntak. Alkoholmetabolitter som acetaldehyd-konjugat, FAEE og etylglucuronid kan måles i flere biofaser, med lengre, til dels betydelig lengre tidsvindu enn alkohol. Målingene er spesifikke, ofte sensitive, men det kvantitative aspekt er lite utredet. Andre rusmidler enn alkohol kan måles særlig i blod og saliva med relativt kort tidsvindu etter inntak. Rusmiddelmetabolitter påvises lettest i urin, men vil også finnes i blod, saliva og hår. Tidsvinduene for påvisning i urin og særlig hår kan ha betydelig lengde. Påvisningen er spesifikk så sant spesifikk analysemetode benyttes, sensitiviteten vil også være metodeavhengig. Resultatene av samtlige biomarkøranalyser krever høy faglig kompetanse for korrekt tolkning

Veitrafikkulykker knyttet til forskrivning av legemidler:En registerbasert kohortstudie,

Purpose: The aim of this study was to examine the risk of being involved in road traffic accidents as drivers among persons using prescribed medicines by utilizing data from population-based registries. The aim of the present paper was to focus on the methodology used in the study. Methods: All Norwegians aged 18-69 in April 2004 to September 2006 (3.1 million), were included in the study. Information on prescriptions, road accidents and emigrations/deaths was obtained from three different population-based registries. A total of 22,000 accidents were observed. The incidence of accidents in exposed and unexposed person-time was compared, by the standardized incidence ratio (SIR). Results: The risk of being involved in an accident was increased in persons exposed for prescribed medicines. The risk was markedly increased in persons exposed for natural opium alkaloids, benzodiazepine tranquillizers, benzodiazepine hypnotics and carisoprodol. A marginal increase or unchanged SIRs were found for NSAIDs, selective beta-2-adrenoreceptor agonists (anti-asthmatics), calcium receptor antagonists and penicillin. Conclusions: We have tested a method using different reference groups and different exposure periods to explore the association between drug use and involvement in traffic accidents. Using these methods, we have shown that exposure for prescribed opiates, benzodiazepines and carisoprodol increased the risk of being involved in an accident as driver. The findings confirm results from other studies. Further steps should be taken to reduce car driving under the influence of these drugs.

An increased risk of road traffic accidents after prescriptions of lithium or valproate?

OBJECTIVES

Studies have shown that lithium may cause psychomotor and cognitive impairment and impose an increased risk of traffic accidents. The antiepileptic drug valproate is also used as a mood stabilizer, but the impact on traffic safety has not been studied. The objective of the present study was to examine whether the use of lithium or valproate increased the risk of being involved in traffic accidents.

METHODS

Between April 2004 and September 2006, information on prescriptions, road accidents and emigrations/deaths was obtained from three Norwegian population-based registries. Data on people between the ages 18-70 (3.1 million) were linked. Exposure consisted of receiving prescriptions for either lithium or valproate. Standardized incidence ratios (SIRs) were calculated by comparing the incidence of motor vehicle accidents during time exposed with the incidence over the time not exposed. Lithium was studied separately from valproate.

RESULTS

During the study period, 20,494 road accidents occurred including 36 while exposed to lithium and 31 while exposed to valproate. The overall accident risk was neither increased after having received prescriptions for lithium (SIR 1.3; 95%CI: 0.9-1.8), nor after having received a prescription for valproate (SIR 0.9; 0.6-1.3). The exception was a three-fold increase in risk for younger female drivers exposed to lithium.

CONCLUSIONS

We found no increase in the traffic accident risk after being exposed to lithium or valproate, except for young female drivers on lithium. This may be because these drugs carry no increased risk or because patients exposed to these drugs refrain from driving.

Determination of ethylglucuronide in oral fluid by ultra-performance liquid chromatography- tandem mass spectrometry

An ultra-performance liquid chromatography-tandem mass spectrometry method has been developed and validated for the determination of ethylglucuronide (EtG) in oral fluid. Sample clean-up was achieved by solid-phase extraction with a Hyper-SEP SAX column. Negative ionization was performed in the multiple reaction monitoring mode. Two transitions were monitored for the analyte and one for the internal standard EtG-d(5). The calibration range was 4.4-222 ng/mL. The recovery of the analyte ranged from 86 to 99%, and the between-assay precisions ranged from 5 to 9% RSD. The limit of quantification was found to be 4.4 ng/mL. The concentration of EtG in oral fluid collected 2-14 h after a moderate alcohol intake varied from 13.3 to 57.7 ng/mL.

Increased locomotor activity induced by heroin in mice: pharmacokinetic demonstration of heroin acting as a prodrug for the mediator 6-monoacetylmorphine in vivo

We investigated the relative importance of heroin and its metabolites in eliciting a behavioral response in mice by studying the relationship between concentrations of heroin, 6-monoacetylmorphine (6MAM), and morphine in brain tissue and the effects on locomotor activity. Low doses (subcutaneous) of heroin (< or =5 micromol/kg) or 6MAM (< or =15 micromol/kg) made the mice run significantly more than mice given equimolar doses of morphine. There were no differences in the response between heroin and 6MAM, although we observed a shift to the left of the dose-response curve for the maximal response of heroin. The behavioral responses were abolished by pretreatment with 1 mg/kg naltrexone. Heroin was detected in brain tissue after injection, but the levels were low and its presence too short-lived to be responsible for the behavioral response observed. The concentration of 6MAM in brain tissue increased shortly after administration of both heroin and 6MAM and the concentration changes during the first hour roughly reflected the changes in locomotor activity. Both the maximal and the total concentration of 6MAM were higher after administration of heroin than after administration of 6MAM itself. The morphine concentration increased slowly after injection and could not explain the immediate behavioral response. In summary, the locomotor activity response after injection of heroin was mediated by 6MAM, which increased shortly after administration. Heroin acted as an effective prodrug. The concentration of morphine was too low to stimulate the immediate response observed but might have an effect on the later part of the heroin-induced behavioral response curve.

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%.

Blood kinetics of ethyl glucuronide and ethyl sulphate in heavy drinkers during alcohol detoxification

Studies of ethyl glucuronide (EtG) blood kinetics have so far been performed on healthy volunteers with ingestion of low to moderate doses of ethanol. These data are not necessarily transferable to heavy drinkers where the consumed doses of ethanol are much higher. The aim of this study was to investigate the pharmacokinetics of EtG and ethyl sulphate (EtS) in blood in heavy drinkers after termination of alcohol ingestion. Sixteen patients from an alcohol withdrawal clinic were included directly after admission. Time of end of drinking, estimated daily intake of ethanol (EDI) and medical history were recorded. Three to five blood samples over 20-43 h were collected from each patient subsequent to admission. The median EDI was 172 g (range 60-564). The first sample was collected median 2.5 h after end of drinking (range 0.5-23.5). Two patients had levels of EtG and EtS below LOQ in all samples, the first collected 19.25 and 23.5 h after cessation of drinking, respectively. Of the remaining 14 patients, one subject, suffering from both renal and hepatic disease, showed concentrations of EtG and EtS substantially higher than the rest of the material. This patient's initial value of EtG was 17.9 mg/L and of EtS 5.9 mg/L, with terminal elimination half lives of 11.9 h for EtG and 12.5 h for EtS. Among the remaining 13 patients, the initial median values were 0.7 g/L (range 0-3.7) for ethanol, 1.7 mg/L (range 0.1-5.9) for EtG and 0.9 mg/L (range 0.1-1.9) for EtS. Elimination occurred with a median half-life of 3.3 h for EtG (range 2.6-4.3) and 3.6 h for EtS (range 2.7-5.4). In conclusion, elimination of EtG in heavy drinkers did not significantly differ from healthy volunteers, and EtS appeared to have similar elimination rate. In the present work, there was one exception to this, and we propose that this could be explained by the patient's renal disease, which would delay excretion of these conjugated metabolites.

Road traffic accident risk in patients with diabetes mellitus receiving blood glucose-lowering drugs. Prospective follow-up study

AIM

To investigate, at a national level, whether patients using insulin or oral glucose-lowering agents had an increased risk of road traffic accidents compared with non-users.

METHODS

All Norwegians aged 18-69 years (3.1 million) were followed from April 2004 until September 2006. Information on drug prescriptions, road traffic accidents and emigration/death was obtained from the following population-based registries: the Prescription Database, the Road Accident Registry and the Central Population Registry. The exposure period was the time from the first prescription of insulin or oral glucose-lowering agent during the study period. The incidence of accidents in the exposed person-time was compared with the incidence of accidents in the unexposed person-time by standardized incidence ratio (SIR).

RESULTS

During the study period, 20 494 road traffic accidents with personal injuries were registered in Norway. One hundred and eighty-three accidents were registered for insulin users not taking oral glucose-lowering agents and 219 for users of oral blood glucose-lowering drugs without insulin. The SIR (95% confidence interval) for all ages and both genders combined were: insulin 1.4 (1.2-1.6), oral glucose-lowering agents 1.2 (1.0-1.3) and users of drugs for peptic ulcer and gastro-oesophageal reflux disease (negative comparators) 1.3 (1.2-1.4). The highest SIRs were found among the youngest insulin users (18-34 years old).

CONCLUSIONS

A slightly increased risk of being involved in a road traffic accident was observed for drivers prescribed insulin, while no increased risk was observed for drivers prescribed oral glucose-lowering agents. The increased risk observed for insulin users was similar to that observed for users of drugs for peptic ulcer and gastro-oesophageal reflux disease.

Methadone and impairment in apprehended drivers

AIMS

According to Norwegian guidelines, patients who are in opioid-assisted rehabilitation programmes are permitted to drive a motor vehicle provided that certain requirements are met. The purpose of this study was to investigate apprehended drivers who had methadone in their blood at the time of apprehension and, further, the relationship between blood methadone concentration and impairment as measured by the clinical test of impairment (CTI).

METHODS

The division of Forensic Toxicology and Drug Abuse (DFTDA) at the Norwegian Institute of Public Heath analyses blood samples from all drivers suspected of driving under the influence of drugs nation-wide. Cases with positive results for methadone in blood were collected over the period 2001-2006.

RESULTS

A total of 635 drivers with methadone found in their blood samples were identified. The majority of drivers were men (>80%), aged between 30 and 40 years. Methadone was the only psychoactive drug detected in blood in only 10 cases. Benzodiazepines were a frequent finding (in approximately 90% of cases). A significant difference in blood methadone concentration was found between cases where only methadone was detected [median 0.46 mg/l (range 0.19-0.65)] and cases where methadone was detected in combination with other psychoactive drugs [median 0.28 mg/l (range 0.06-1.24)]. A CTI had been carried out, in conjunction with blood sampling, in 577 of the cases. A concentration-impairment relationship was not seen for methadone in these cases.

CONCLUSIONS

Cases of driving impairment involving methadone alone were very rare, with combination use most frequent. No correlation between methadone concentration and impairment as judged by the CTI was seen either for these cases or for the material as a whole.

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.

Prevalence of alcohol and drugs among Norwegian motor vehicle drivers: a roadside survey

The objective of the study was to determine the prevalence of alcohol, psychoactive medicinal drugs and illegal drugs among drivers in Norwegian road traffic. Drivers of motor vehicles were selected from April 2005 to April 2006 in the south-eastern part of Norway, surrounding, but not including the capital, Oslo. A stratified two-stage cluster sampling procedure was used. In the first stage, random road sites and time intervals were selected, and in the second stage, drivers were stopped by random at those sites and time intervals. Altogether about 12,000 drivers were asked to provide a sample of oral fluid (saliva) and answer a few questions. Samples of oral fluid were obtained from 88% of the drivers, of whom 30% were females and 70% males. The prevalence of each drug was estimated by a weighted average using weights adjusted for under- or over-sampling compared to traffic statistics. Alcohol or drugs were found in oral fluid samples of 4.5% of the drivers; alcohol in 0.4%, psychoactive medicinal drugs in 3.4%, and illegal drugs in 1.0%. Illegal drugs were found more frequently in samples from younger drivers, while psychoactive medicinal drugs were more frequently found in samples from older drivers. Psychoactive medicinal drugs were more prevalent among females than males, among drivers stopped on working days rather than weekends, and among those who reported annual driving distances less than 16,000 km. The drugs found most frequently were zopiclone (1.4%), benzodiazepines (1.4%), codeine (0.8%), tetrahydrocannabinol (0.6%) and amphetamines (0.3%). Two or more drugs were found in 0.6% of the samples, corresponding to 15% of the drug-positive drivers.

Guidelines for research on drugged driving

AIMS

A major problem in assessing the true public health impact of drug-use on driving and overall traffic safety is that the variables being measured across studies vary significantly. In studies reported in a growing global literature, basic parameters assessed, analytical techniques and drugs tested are simply not comparable due to lack of standardization in the field. These shortcomings severely limit the value of this research to add knowledge to the field. A set of standards to harmonize research findings is sorely needed. This project was initiated by several international organizations to develop guidelines for research on drugged driving.

METHODS

A September 2006 meeting of international experts discussed the harmonization of protocols for future research on drugged driving. The principal objective of the meeting was to develop a consensus report setting guidelines, standards, core data variables and other controls that would form the basis for future international research. A modified Delphi method was utilized to develop draft guidelines. Subsequently, these draft guidelines were posted on the internet for global review, and comments received were integrated into the final document.

RESULTS

The Guidelines Document is divided into three major sections, each focusing upon different aspects of drugged driving research (e.g. roadside surveys, prevalence studies, hospital studies, fatality and crash investigations, etc.) within the critical issue areas of 'behavior', 'epidemiology' and 'toxicology'. The behavioral section contains 32 specific recommendations; (2) epidemiology 40 recommendations; and (3) toxicology 64 recommendations.

CONCLUSIONS

It is anticipated that these guidelines will improve significantly the overall quality of drugged driving research and facilitate future cross-study comparisons nationally and globally.

Minor increase in risk of road traffic accidents after prescriptions of antidepressants: a study of population registry data in Norway

OBJECTIVES

Experimental studies have shown that both depression and the use of antidepressants may impair the ability to drive a motor vehicle. Population-based studies have been inconclusive. Differences in results have been shown for cyclic, sedating antidepressants and newer, nonsedating antidepressants. The objective of the present study was to examine whether the use of antidepressants by drivers increased the risk of being involved in traffic accidents.

METHOD

From April 2004 to September 2006, information on prescriptions, road accidents, and emigrations/deaths was obtained from 3 Norwegian population-based registries. Data on people between the ages 18-69 (N = 3.1 million) were linked. Exposure consisted of receiving prescriptions for any antidepressants. Standardized incidence ratios (SIRs) were calculated by comparing the incidence of accidents during time exposed with the incidence over the time not exposed. Sedating antidepressants (tricyclic antidepressants, mianserin, and mirtazapine) were studied together as one group, and newer, nonsedating antidepressants (selective serotonin reuptake inhibitors, moclobemide, venlafaxine, and reboxetine) as another.

RESULTS

During the study period, 20,494 road accidents with personal injuries occurred, including 204 and 884 in which the driver was exposed to sedating antidepressants or newer, nonsedating antidepressants, respectively. The traffic accident risk increased slightly for drivers who had received prescriptions for sedating antidepressants (SIR = 1.4, 95% CI = 1.2 to 1.6) or nonsedating antidepressants (SIR = 1.6, 95% CI = 1.5 to 1.7). The SIR estimates were similar for male and female drivers and slightly higher for young drivers (18-34 years of age) using older sedative antidepressants. SIR estimates did not change substantially for different time periods after dispensing of the prescription, for concomitant use of other impairing drugs, or for new users.

CONCLUSION

There was a slightly increased risk of being involved in a traffic accident after having received a prescription for any antidepressants. In the present study, it was not possible to determine whether this increase was due to the antidepressant, the effect of the depression, or characteristics of the patients being prescribed these drugs.

Frequent detection of benzodiazepines in drugged drivers in Norway

OBJECTIVE

To describe the Norwegian system for handling suspected drugged driving cases according to an impairment-based law, with primary focus on benzodiazepines (BZDs), blood concentrations and combination with other psychoactive compounds.

METHODS

Routines for handling suspected driving under the influence of drugs other than alcohol are described. These include primary police investigation, blood sampling, and clinical tests of impairment performed by a police physician, a standard analytical program covering the most relevant illegal drugs and medicines relevant to traffic safety (approximately 25 compounds), and expert witness statements prepared for the court. The drug use patterns, blood drug concentrations, and frequency of multi-drug use have been recorded, with primary focus on benzodiazepines (BZDs). Use of BZDs among apprehended drivers has been compared with patient prescriptions recorded for the same BZDs.

RESULTS

One or more drugs have been detected in approximately 80% of the cases received for analysis every year. BZDs have been the most prevalent drugs and have been detected in 38-57% of the cases, which is more frequent than other common illegal drugs; e.g., tetrahydrocannabinol (THC; 30-43%) and amphetamine (33-39%). The majority of the BZDs have been detected at supratherapeutic blood concentrations and frequently in combination with illegal drugs, other psychoactive medicines, or alcohol. Less than 5% of the BZDs (except for nitrazepam - 7.6%) have been found to be the only drug present at therapeutic blood levels. The majority of the drivers were 20-39 years old (median age 29-33), while the majority of BZDs prescribed were to users over 50 years of age.

CONCLUSIONS

Drivers with BZD detected are probably not representative of ordinary patients with BZD prescriptions, as shown by the age disparity of drivers and patients. The frequent detection of BZDs suggests that these compounds should be included in the analytical program used for blood samples from apprehended drivers and for studies on drug involvement in road traffic accidents and risk calculations.

Disappearance of ethyl glucuronide during heavy putrefaction

INTRODUCTION

There are previous publications showing the use of ethyl glucuronide (EtG), a non-oxidative metabolite of ethanol, as a marker of ante-mortem ingestion of alcohol in forensic autopsy cases. The problem of possible degradation or formation of EtG during putrefaction is however not well studied and the aim of this study was to investigate the possibility of false negative and false positive EtG results by an in vitro study. Further, we used the information from the in vitro study on real cases, to get an impression of the practical problem of degradation or formation of EtG.

METHODS

An in vitro study was carried out to study the concentrations of EtG in blood samples under controlled conditions during putrefaction. In addition, to illustrate the practical problem of degradation or formation of EtG, we used routine samples analysed for EtG in blood. Blood samples from forensic autopsies with ethanol detected but EtG not detected in blood, and therefore suspected post-mortem ethanol formation, were identified. Fifteen such cases had urine samples available, and these were analysed for EtG. We hypothesised that since concentrations are often higher in urine, there would still be traces of EtG left in this medium if post-mortem degradation was the reason for the negative result in blood.

RESULTS

In this in vitro experiment, EtG was very unstable in blood samples at 30/40 degrees C without preservatives. On the other hand, EtG was stable with potassium fluoride at room temperature, and there was no formation of EtG either at 30 degrees C without preservatives, or at room temperature with potassium fluoride. Of the 15 routine cases where EtG in blood was negative, and the ethanol detected was assumed endogenous, six were positive for EtG in urine. In these cases, ethanol was probably ingested, and the negative EtG in blood may be a false negative result due to degradation during putrefaction.

CONCLUSION

Analysis of EtG in blood is a helpful tool to determine in vivo ingestion of ethanol in post-mortem cases. A negative result, however, especially in heavily putrefied cases, must be interpreted with caution. Analysis of an additional medium would be valuable in these cases.