Δ9-tetrahydrocannabinol (THC) is present in the body between smoking sessions in occasional non-daily cannabis users.

BACKGROUND: THC can be measured in blood up to a month after last intake in heavy cannabis users. The cognitive deficits during abstinence have been hypothesized to be at least in part due to residual THC in brain. To which extent THC accumulation will occur after occasional cannabis use has gained limited attention. We aimed to predict THC-levels between smoking sessions in non-daily as well as daily cannabis users and to compare these predictions with published THC levels. METHODS: Predictions were based on pharmacokinetic principles on drug accumulation after repeated dosing, applied to different cannabis smoking patterns, using data from a three-compartment model for THC pharmacokinetics and results on the terminal elimination half-life of THC in humans. We searched the literature for THC measurements which could be compared with these predictions. We found no such results from controlled studies of long-term repeated cannabis consumption of known THC amounts. Thirteen published studies contained, however, enough information on cannabis use and results from THC-measurements to make tentative comparisons with the predictions. RESULTS: The predictions of THC-plasma levels present after different cannabis smoking patterns assuming terminal elimination half-lives of THC of 21.5 h or longer, had some support in published THC levels measured in individuals self-reporting their cannabis consumption. We found no consistent discrepancies between the predictions and reported THC plasma levels after non-daily or daily cannabis use. The predictions indicate that THC might be present in plasma between smoking sessions above usual analytical limits when smoking every third and second day, and at lower levels after once weekly smoking. CONCLUSIONS: The study indicates that THC might be present continuously even in non-daily smokers at low levels, even if the smoking occasions are separated by a week. This is different from alcohol, where ethanol has disappeared after a day. From a toxicological point of view the persistance of THC in the brain, raises questions whether this should be given more attention as with other toxicological thinking where long-term presence of bioactive substances gives rise to concern. There are some uncertainties in this analysis, and controlled studies on THC-accumulation accompanying different use patterns seem warranted.

Methodologies for establishing the relationship between alcohol/drug use and driving impairment - Differences between epidemiological, experimental, and real-case studies.

Experimental, epidemiological, and real-case studies have different advantages and limitations when used to study the effect of substance use on the risk for involvement in a road traffic crash. It is easier to perform well-controlled experimental studies than well-controlled epidemiological studies due to difficulties related to selection bias, information bias, and confounding. On the other hand, it is difficult or impossible to perform experimental studies using single and repeated substance doses similar to those used by drivers and problematic drugs users. Real-case studies indicate which substances may cause observed impairment and involvement in road traffic crashes and at which concentrations; however, those studies cannot be used to quantify crash risks or determine causality. All three types of studies are needed to obtain a broad and complete picture as they may complement each other when assessing the effects of substance use on road traffic safety.

Driving under the influence of psychoactive substances - A historical review.

Important events in the history of driving under the influence of alcohol (DUI) and/or other drugs (DUID) are reviewed covering a period of approximately 100 years. This coincides with major developments in the pharmaceutical industry and the exponential growth in motor transportation worldwide. DUID constitutes an interaction between the driver, the motor-driven vehicle, and one or more psychoactive (mind-altering) substances. In this connection, it is important to differentiate between drugs intended and used for medical purposes (prescription or licit drugs) and recreational drugs of abuse (illicit drugs). All chemicals with a mechanism of action in the central nervous system (brain and spinal cord) are potentially dangerous to use when skilled tasks, such as driving, are performed. The evidence necessary to charge a person with drug-impaired driving has evolved over many years and initially rested on a driver's own admissions and observations made about the driving by police officers or eyewitnesses. Somewhat later, all suspects were examined by a physician, whose task was to ask questions about any recent ingestion of alcohol and/or other drugs and to administer various clinical tests of impairment. By the 1940s-1950s, the driver was asked to provide samples of blood, breath, or urine for toxicological analysis, although the test results served only to verify the type of drug causing impairment of the driver. The current trend in DUID legislation is toward zero-tolerance or concentration per se statutes, which are much more pragmatic, because behavioral evidence of impairment is no longer a lynchpin in the prosecution case. This legal framework puts considerable emphasis on the results of toxicological analysis; therefore, the methods used must be accurate, precise, and fit for forensic purposes. Many traffic delinquents charged with DUI or DUID suffer from a substance use and/or personality disorder, with high recidivism rates. In addition to conventional penalties and sanctions for drug-related traffic crimes, many offenders would probably benefit from a medical intervention, such as counseling, rehabilitation, and treatment for substance use disorder, which often coexists with a mental health problem.

The interplay between cognitive ability, alcohol consumption, and health characteristics.

BACKGROUND: Higher cognitive ability is associated with favourable health characteristics. The relation between ability and alcohol consumption, and their interplay with other health characteristics, is unclear. We aimed to assess the relationship between cognitive ability and alcohol consumption and to assess whether alcohol consumption relates differently to health characteristics across strata of ability. METHODS: For 63 120 Norwegian males, data on cognitive ability in early adulthood were linked to midlife data on alcohol consumption frequency (times per month, 0-30) and other health characteristics, including cardiovascular risk factors and mental distress. Relations were assessed using linear regression and reported as unstandardised beta coefficients [95% confidence interval (CI)]. RESULTS: The mean ± s.d. frequency of total alcohol consumption in the sample was 4.0 ± 3.8 times per month. In the low, medium, and high group of ability, the frequencies were 3.0 ± 3.3, 3.7 ± 3.5, and 4.7 ± 4.1, respectively. In the full sample, alcohol consumption was associated with physical activity, heart rate, fat mass, smoking, and mental distress. Most notably, each additional day of consumption was associated with a 0.54% (0.44-0.64) and 0.14% (0.09-0.18) increase in the probability of current smoking and mental distress, respectively. In each strata of ability (low, medium, high), estimates were 0.87% (0.57-1.17), 0.48% (0.31-0.66) and 0.49% (0.36-0.62) for current smoking, and 0.44% (0.28-0.60), 0.10% (0.02-0.18), and 0.09% (0.03-0.15) for mental distress, respectively. CONCLUSIONS: Participants with low cognitive ability drink less frequently, but in this group, more frequent alcohol consumption is more strongly associated with adverse health characteristics.

Driving under the influence of non-alcohol drugs--An update. Part II: Experimental studies.

Experimental studies on the impairing effects of drugs of relevance to driving-related performance published between 1998 and 2015 were reviewed. Studies with on-the-road driving, driving simulators, and performance tests were included for benzodiazepines and related drugs, cannabis, opioids, stimulants, GHB, ketamine, antihistamines, and antidepressants. The findings in these experimental studies were briefly discussed in relation to a review of epidemiological studies published recently. The studies mainly concluded that there may be a significant psychomotor impairment after using benzodiazepines or related drugs, cannabis, opioids, GHB, or ketamine. Low doses of central stimulants did not seem to cause impairment of driving behavior.

International trends in alcohol and drug use among vehicle drivers.

Trends in the use of alcohol and drugs among motor vehicle drivers in Australia, Brazil, Norway, Spain, and the United States have been reviewed. Laws, regulations, enforcement, and studies on alcohol and drugs in biological samples from motor vehicle drivers in general road traffic and fatal road traffic crashes (RTCs) are discussed. Roadside surveys showed a reduction of drunk driving over time in the studied countries; however, the pattern varied within and between different countries. The reduction of alcohol use may be related to changes in road traffic laws, public information campaigns, and enforcement, including implementation of random breath testing or sobriety checkpoints. For non-alcohol drugs, the trend in general road traffic is an increase in use. However, drugs were not included in older studies; it is therefore impossible to assess the trends over longer time periods. Data from the studied countries, except Brazil, have shown a significant decrease in fatal RTCs per 100,000 inhabitants over the last decades; from 18.6 to 4.9 in Australia, 14.5 to 2.9 in Norway, 11.1 to 3.6 in Spain, and 19.3 to 10.3 in the United States. The number of alcohol-related fatal RTCs also decreased during the same time period. The proportion of fatal RTCs related to non-alcohol drugs increased, particularly for cannabis and stimulants. A general challenge when comparing alcohol and drug findings in biological samples from several countries is connected to differences in study design, particularly the time period for performing roadside surveys, biological matrix types, drugs included in the analytical program, and the cutoff limits used for evaluation of results. For RTC fatalities, the cases included are based on the police requests for legal autopsy or drug testing, which may introduce a significant selection bias. General comparisons between high-income countries and low- and middle-income countries as well as a discussion of possible future trends are included.

Driving Under the Influence of Non-Alcohol Drugs--An Update Part I: Epidemiological Studies.

Epidemiological studies of the association between drug use and involvement in road traffic crashes (RTCs) published from January 1998 to February 2015 have been reviewed. Cohort andpopulation studies compared RTC involvement among drug users and non-drug users, case-control studies compared drug use among RTC-involved and non-RTC-involved drivers, and responsibility studies and case-crossover studies were performed for RTC-involved drivers. Difficulties associated with the types of studies are discussed with a special focus on case-control studies. Statistically significant associations between drug use and RTC involvement were found for benzodiazepines and z-hypnotics in 25 out of 28 studies, for cannabis in 23 out of 36 studies, for opioids in 17 out of 25 studies, for amphetamines in 8 out of 10 studies, for cocaine in 5 out of 9 studies, and for antidepressants in 9 out of 13 studies. It was a general trend among studies that did not report significant associations between the use of these drugs and increased RTC risk that they often had either poor statistical power or poor study design compared to studies that found an association. Simultaneous use of two or more psychoactive drugs was associated with higher RTC risk. Studies on the combination of alcohol and drugs have not been reviewed in this article even though this combination is known to be associated with the highest RTC risk.

Determination of dopamine concentrations in brain extracellular fluid using microdialysis with short sampling intervals, analyzed by ultra high performance liquid chromatography tandem mass spectrometry.

INTRODUCTION: An increase in striatal dopamine is considered essential for the rewarding and reinforcing effects of drugs of abuse. We have developed and validated an ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the analysis of dopamine in rat brain extracellular fluid (ECF) sampled with microdialysis. The method was applied to monitor changes in dopamine concentrations over time after an intravenous bolus injection of heroin. METHODS: Dopamine and dopamine-d3 were analyzed using a 2.1×100mm Aquity T3 column, 1.7µm particle size, with a formic acid and methanol gradient. The run time of the method was 2.5min including equilibration time. RESULTS: The method had an LOQ of 0.15ng/mL, which equals 0.55pg on column. The calibration curves were linear in the tested area of 0.15 to 16ng/mL. Inter-assay coefficients of variation varied between 5-17%, with an accuracy expressed as bias of -10 to 5%. The intra-assay coefficients of variation varied between 9-15%, with an accuracy of -3-7%. DISCUSSION: Heroin metabolism is very rapid. Sampling intervals of only 2min were thus required to obtain an adequate number of samples of dopamine analysis accompanying the concentration-time profile of opioids in the brain. Applying a flow of 2µL/min, 4µL of dialysate were sampled at 2min intervals, in 7µL internal standard. The injection volume onto the UPLC column was 10µL. Analyses of microdialysate samples from a rat given heroin i.v. showed that it was possible to measure baseline levels and rapid changes in dopamine concentrations with very short sampling periods.

Pharmacokinetic interactions between ethanol and heroin: a study on post-mortem cases.

INTRODUCTION: Ethanol and heroin are both depressant drugs on the central nervous system, and combined use is known to be dangerous due to pharmacodynamic interactions, leading to an even higher risk of respiratory depression and death. In addition, previous studies have suggested a pharmacokinetic interaction between ethanol and the metabolism of heroin. The aim of the present study was to investigate if there was a pharmacokinetic interaction between heroin and ethanol, by comparing concentrations of heroin metabolites in cases with and without ethanol, as detected in blood samples collected from a large material of forensic autopsy cases. METHODS: The material consisted of 1583 forensic autopsy cases, all containing 6-monoacetylmorphine (6-MAM), as evidence of heroin intake, in either blood or urine samples, from the time period between the 1st of January 2000 and the 31st of December 2012. Due to the high risk of post-mortem ethanol formation in cases revealing blood ethanol concentrations between 0.1 and 0.3‰, these cases were excluded from the study, along with cases where the analysis for ethanol was missing. After this exclusion of cases, the material (n=1474) was divided into two groups; one group where ethanol was not detected in blood (n=1160), and another group where ethanol was detected in blood at or above the concentration of 0.4‰ (n=314). Furthermore, the material was also divided into two other subgroups; one group where 6-MAM was detected in blood samples, indicating a very recent intake of heroin, and another group where 6-MAM was detected in the urine, but not in blood, indicating a less recent heroin intake. RESULTS: The concentration ratios of morphine/6-MAM, morphine-3-glucuronide (M3G)/morphine, and morphine-6-glucuronide (M6G)/morphine in blood samples, were all significantly lower in the ethanol positive cases compared with that of the ethanol negative cases. For the subgroup of cases revealing a very recent intake of heroin (n=645), only the morphine/6-MAM ratio was significantly lower in the ethanol positive cases than in the ethanol negative cases. For the subgroup of cases with a less recent heroin intake (n=817), lower M3G/morphine and M6G/morphine ratios were found among the ethanol positive cases. CONCLUSIONS: The results indicate that ethanol inhibits two steps in the heroin metabolism; the hydrolysis of 6-MAM to morphine, and the glucuronidation of morphine to M3G and M6G. This pharmacokinetic interaction could further complicate the outcome after combined use of heroin and ethanol, in addition to the already well-known pharmacodynamic interactions.

Role of 6-monoacetylmorphine in the acute release of striatal dopamine induced by intravenous heroin.

After injection, heroin is rapidly metabolized to 6-monoacetylmorphine (6-MAM) and further to morphine. As morphine has been shown to increase striatal dopamine, whereas 6-MAM has not been studied in this respect, we gave i.v. injections of 3 µmol 6-MAM, morphine or heroin to rats. Opioids were measured in blood, and dopamine and opioids in microdialysate from brain striatal extracellular fluid (ECF), by UPLC-MS/MS. After 6-MAM injection, 6-MAM ECF concentrations increased rapidly, and reached Cmax of 4.4 µM after 8 min. After heroin injection, 6-MAM increased rapidly in blood and reached Cmax of 6.4 µM in ECF after 8 min, while ECF Cmax for heroin was 1.2 µM after 2 min. T max for morphine in ECF was 29 and 24 min following 6-MAM and heroin administration, respectively, with corresponding Cmax levels of 1 and 2 µM. Dopamine levels peaked after 8 and 14 min following 6-MAM and heroin administration, respectively. The dopamine responses were equal, indicating no dopamine release by heroin per se. Furthermore, 6-MAM, and not morphine, appeared to mediate the early dopamine response, whereas morphine administration, giving rise to morphine ECF concentrations similar to those observed shortly after 6-MAM injection, did not increase ECF dopamine. 6-MAM appeared accordingly to be the substance responsible for the early increase in dopamine observed after heroin injection. As 6-MAM was formed rapidly from heroin in blood, and was the major substance reaching the brain after heroin administration, this also indicates that factors influencing blood 6-MAM concentrations might change the behavioural effects of heroin.

Levels of heroin and its metabolites in blood and brain extracellular fluid after i.v. heroin administration to freely moving rats.

BACKGROUND AND PURPOSE: Heroin, with low affinity for µ-opioid receptors, has been considered to act as a prodrug. In order to study the pharmacokinetics of heroin and its active metabolites after i.v. administration, we gave a bolus injection of heroin to rats and measured the concentration of heroin and its metabolites in blood and brain extracellular fluid (ECF). EXPERIMENTAL APPROACH: After an i.v. bolus injection of heroin to freely moving Sprague-Dawley rats, the concentrations of heroin and metabolites in blood samples from the vena jugularis and in microdialysis samples from striatal brain ECF were measured by ultraperformance LC-MS/MS. KEY RESULTS: Heroin levels decreased very fast, both in blood and brain ECF, and could not be detected after 18 and 10 min respectively. 6-Monoacetylmorphine (6-MAM) increased very rapidly, reaching its maximal concentrations after 2.0 and 4.3 min, respectively, and falling thereafter. Morphine increased very slowly, reaching its maximal levels, which were six times lower than the highest 6-MAM concentrations, after 12.6 and 21.3 min, with a very slow decline during the rest of the experiment and only surpassing 6-MAM levels at least 30 min after injection. CONCLUSIONS AND IMPLICATIONS: After an i.v. heroin injection, 6-MAM was the predominant opioid present shortly after injection and during the first 30 min, not only in the blood but also in rat brain ECF. 6-MAM might therefore mediate most of the effects observed shortly after heroin intake, and this finding questions the general assumption that morphine is the main and most important metabolite of heroin.

Simultaneous measurement of heroin and its metabolites in brain extracellular fluid by microdialysis and ultra performance liquid chromatography tandem mass spectrometry.

INTRODUCTION: The pharmacokinetic profile and systemic bioavailability of a substance is often described by blood or total tissue concentrations. For centrally acting drugs, like opioids, the free fraction of active compound in brain extracellular fluid (ECF) is more likely to be correlated to the pharmacodynamic effects than the blood concentrations. Drugs of abuse, like heroin, are often administered intravenously as bolus injections, and the blood concentrations might change rapidly due to metabolism and distribution. The aim of our study was to establish a method to measure the free fraction of heroin and its metabolites in brain ECF, and follow their fast changes in concentration. METHODS: Sprague-Dawley rats were injected intravenously with a bolus of heroin. Heroin and its main metabolites 6-monoacetylmorphine, morphine and morphine-3-glucuronide were measured simultaneously. Brain microdialysis was used for sampling and a method for quantification using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed. Deuterated analogues for each analyte were included in the microdialysis perfusion solution as calibrators for recovery estimation. RESULTS: A highly sensitive UPLC-MS/MS method allowed short sampling intervals, down to one minute, and the simultaneous detection of each analyte and its specific deuterated analogues, making possible the individual recovery calculation for each compound of interest. This method allowed us to determine the pharmacokinetic profiles of heroin and its metabolites in brain-ECF in the same animal after an intravenous injection of heroin. DISCUSSION: Our method makes detecting concurrently the rapid changes in concentrations of heroin and its metabolites in brain ECF possible, despite the rapid metabolism of heroin. Recovery was measured specifically for each analyte in the same sample by carefully combining different deuterated analogues. This technique can be applied to pharmacokinetic studies where more than one compound of interest has to be monitored, and to study distribution of prodrugs or drugs with active metabolites.

Oral fluid is a viable alternative for monitoring drug abuse: detection of drugs in oral fluid by liquid chromatography-tandem mass spectrometry and comparison to the results from urine samples from patients treated with Methadone or Buprenorphine.

Oral fluid is an alternative biological matrix that might have advantages over urine for drug analysis in treatment programs. A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method has been used for screening 32 of the most commonly abused drugs and their metabolites in 0.5 mL preserved oral fluid, and the results were compared to results obtained from urine samples taken at the same time. In all, 164 pairs of oral fluid and urine were obtained from 45 patients stabilized on either methadone or buprenorphine. The total number of detections of drugs other than buprenorphine or methadone was 535 in oral fluid and 629 in urine. Morphine was found more often in urine (n = 66) than in oral fluid (n = 48), whereas the opposite was the case for 6-monoacetylmorphine (n = 20 in urine and n = 48 in oral fluid). Methadone showed the same detection frequency in urine and oral fluid (n = 75), whereas amphetamine (n = 45 in urine and n = 51 in oral fluid), methamphetamine (n = 39 in urine and n = 45 in oral fluid), and N-desmethyldiazepam (n = 37 in urine and n = 51 in oral fluid) were detected slightly more often in oral fluid. The other benzodiazepines, cannabis and cocaine were found more frequently in urine samples. If using a sensitive LC-MS-MS technique, oral fluid might be a good alternative to urine for detection of relatively recent use of drugs.

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.

Determination of cotinine in pericardial fluid and whole blood by liquid chromatography-tandem mass spectrometry.

Cotinine is the main metabolite of nicotine and is used as an indicator of exposure to tobacco smoke. A method has been developed for quantification of cotinine in pericardial fluid and whole blood collected from autopsy casework involving cases of infant death. Sample clean-up was achieved by solid-phase extraction with a mixed-mode column. Cotinine was quantified by liquid chromatography-tandem mass spectrometry. Positive ionization was performed in the multiple reaction monitoring mode. Two transitions were monitored for the analyte and one for the internal standard, cotinine-d(3). The calibration range was 0.9-176 ng/mL for cotinine in both matrixes. The recovery of the analyte ranged from 86 to 92%, and the between-assay precisions ranged from 4 to 6% relative standard deviation. Whole blood and pericardial fluid samples from 95 infant deaths obtained during autopsy were analyzed. A strong correlation (R(2) = 0.97) was found between the cotinine concentrations in pericardial fluid and blood. The correlation was not affected by the postmortem time interval. This study demonstrates that pericardial fluid may be an alternative specimen to blood for quantification of cotinine in forensic autopsies.

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.

Rearrest rates among Norwegian drugged drivers compared with drunken drivers.

The rearrest rates among Norwegian drugged (n=1102) and a group of drunken drivers (n=850) (BAC: 0.16-0.19%) apprehended during 1992, were 57% (n=629) and 28% (n=238), respectively, when followed prospectively for 7 years. The most important risk factors for recidivism among drugged drivers were previous arrests for drugged or drunken driving (rearrest rate among previous arrests: 73%, no previous arrest: 42%), multi-drug detection at selection (multi-drug: 62%, single drug: 41%), sex (male: 61%, female: 35%) and age (below 36 years: 60%, 36 years and older: 44%). Most of the recidivist drugged drivers were rearrested during the year of selection (21%), followed by 13, 7 and 6%, retrospectively, during the following years. When followed both retrospectively and prospectively for a period extending from 1984 to 1998, 71% (n=779) and 40% (n=344) of the selected drugged and drunken drivers, respectively, were arrested two or more times.

Urinary excretion of diazepam metabolites in healthy volunteers and drug users.

Urinary excretion profiles of diazepam metabolites were investigated. The subjects were healthy volunteers receiving one single 10-mg dose of diazepam or drug abusers starting a prison sentence. Urinary excretion of metabolites was analysed by immunological screening, liquid chromatography and gas chromatography-mass spectrometry. Relating the metabolite concentration to creatinine concentration in the specimens decreased sample-to-sample variations. In some cases such correction could protect a subject from erroneous accusations of a new intake.