Psychomotor performance after intake of zopiclone compared with intake of ethanol: a randomized, controlled, double-blinded trial

Driving under the influence of zopiclone: Elimination between two consecutive blood samples

AIM

Zopiclone is a widely used hypnotic drug which is frequently detected in apprehended drivers. For assessments in forensic cases, the elimination half-life (t1/2) of a drug is sometimes important. A t1/2 of 3.5-6.5 h for zopiclone is previously reported in healthy individuals, but different factors like age and drug-interactions can affect the t1/2 of zopiclone. The aim of this study was to describe concentrations of zopiclone and co-ingestion of additional drugs in apprehended drivers, and to investigate the t1/2 of zopiclone based on two consecutive blood samples.

METHODS

Data was collected from apprehended drivers in Norway between 2003 and 2021. All cases where zopiclone was detected were included. In a subset of the material, two consecutive whole blood samples were collected ≥ 20 and < 60 min apart. Concentrations of zopiclone in blood were determined by LC-MS or UHPLC-MS/MS. The elimination and t1/2 of zopiclone was estimated from the concentration change of zopiclone and the time interval between the two consecutive blood samples, under the assumption of first order kinetics.

RESULTS

The median concentration among all zopiclone positive cases was 0.044 mg/L (IQR 0.070 mg/L) (n = 2401). The most frequent additional drugs detected were ethanol (36%), diazepam (22%), amphetamine (14%) and THC (14%). In zopiclone-only cases (n = 364), the median concentration of zopiclone was 0.066 mg/L (IQR 0.115 mg/L). In 112 cases, two consecutive blood samples were collected. Of these, 28 cases showed increasing concentrations of zopiclone between the two sampling time points. Among the cases in which the concentration decreased (n = 84), the median C1 was 0.048 mg/L (IQR 0.062 mg/L) and the median C2 was 0.043 mg/L (IQR 0.056 mg/L). A Bayesian statistical model was used to obtain the posterior distribution of t1/2. The posterior median of t1/2 was estimated to 3.1 h (IQR=0.39 h) when including only the cases showing decreasing concentrations, and this increased to 3.8 h (IQR=0.52 h) when also including samples showing non outlying increase in concentrations. There was no statistically significant gender difference in the calculated half-lives (two-sided Mann-Whitney U test, p = .525).

CONCLUSIONS

This study showed that zopiclone is frequently detected in apprehended drivers in supra therapeutic concentrations and poly drug cases. The elimination of zopiclone in blood from two consecutive blood samples indicated an apparent t1/2 of between 3.1 and 3.8 h, which is within the lower range of what previous experimental studies on healthy individuals have reported.

A comparison of driving related skills impaired by ethanol and zopiclone

Objective: Ethanol and zopiclone are both sedating drugs that impair traffic relevant skills, but that show vast differences in epidemiological traffic risk. One explanation for this could be that they impair various kinds of skills differently, but this is less previously studied. The aim of this study was to compare effects of zopiclone and ethanol on a large battery of computerized psychomotor and cognitive tests according to different test classifications. Methods: Ethanol (50 grams), zopiclone 5 mg, zopiclone 10 mg or placebo was administered in a randomized trial with a cross-over design. Blood was sampled nine times after administration and analyzed for zopiclone and ethanol using fully validated methods. The computerized tests Connors Continuous Performance Test (CPT), Stockings of Cambridge (SOC) and choice reaction time (CRT) was performed at baseline and after administration. The three tests yielded fifteen different test components, which were categorized according to the three well-known behavior levels (automative behavior, control behavior and executive planning). Secondly, they were categorized into tests measuring "reaction time", "impulsivity" and "attention/cognition". Results: On all tests belonging to behavior level 1 and on all tests measuring "reaction time", more subjects were impaired by zopiclone than ethanol. On all tests measuring "impulsivity", more subjects were impaired by ethanol than zopiclone. Conclusion: Zopiclone and ethanol both lead to impairment, but have a different profile on what kind of tests and neurocognitive functions they mostly impair. This could be important in the understanding of the differences in traffic risk connected to these two drugs.

Conversion factors for assessment of driving impairment after exposure to multiple benzodiazepines/z-hypnotics or opioids

AIMS

Norway has introduced legal concentration limits in blood for 28 non-alcohol drugs in driving under the influence cases. As of 2016 this legislation also regulates the assessment of combined effects of multiple benzodiazepines and opioids. We herein describe the employed methodology for the equivalence tables for concentrations of benzodiazepines/z-hypnotics and opioids implemented in the Norwegian Road Traffic Act.

METHODS

Legislative limits corresponding to impairment at blood alcohol concentrations (BAC) of 0.02%, 0.05% and 0.12% were established for 15 different benzodiazepines and opioids. This was based on a concept of a linear relationship between blood drug concentration and impairment in drug naïve users. Concentration ratios between these drugs were used to establish conversion factors and calculate net impairment using diazepam and morphine equivalents.

RESULTS

Conversion factors were established for 14 benzodiazepines/z-hypnotics (alprazolam, bromazepam, clobazam, clonazepam, etizolam, flunitrazepam, lorazepam, nitrazepam, nordiazepam, oxazepam, phenazepam, temazepam, zolpidem and zopiclone) and two opioids (methadone and oxycodone).

CONCLUSIONS

Conversion factors to calculate diazepam and morphine equivalents for benzodiazepines/z-hypnotics and selected opioids, respectively, have been operative in the Norwegian Road Traffic Act as of February 2016. Calculated equivalents can be applied by the courts to meter out sanctions.

Zopiclone concentrations in oral fluid and blood after, administration of therapeutic doses of zopiclone

PURPOSE

Little is known about the relationship between concentrations in oral fluid (OF) and blood for the widely prescribed hypnotic drug zopiclone. The purpose of this study was to investigate the usefulness of OF zopiclone concentrations to predict blood zopiclone concentrations in order to introduce OF testing as an alternative to more cumbersome blood testing.

METHODS

16 healthy young male volunteers received capsules of either 5 or 10mg zopiclone on two different study days separated by at least one week. Blood and OF were collected simultaneously at baseline and 9 times after intake of zopiclone on each study day. In addition an OF sample was collected 24-81h after intake. Lunch was served between samples taken 2.5 and 3.5h after intake. All samples were analysed for zopiclone, and the cut-off was 10ng/ml in blood and 0.2ng/ml in OF-buffer mixture.

RESULTS

Zopiclone was detected in all OF samples during the study day. After 24-81h, all subjects were also positive for zopiclone in OF, except from three subjects ingesting the 5mg dose. In a single case zopiclone was detected in a baseline OF sample 14days after intake on an earlier study day. Zopiclone was detected in both OF and blood in 231 OF/blood pairs, and a significant but weak correlation between OF and blood concentration was seen (R² of 0.30). The median (range) zopiclone OF/blood concentration ratio (ZOBCR) for all samples were 3.3 (0.8-18). The ZOBCR decreased when the OF volume increased. After 30 of 31 given doses of zopiclone, the ZOBCR was higher in samples collected before lunch than samples collected after lunch.

DISCUSSION

Vast intra- and interindividual differences in ZOBCR were found, and the correlation between OF and blood concentration was less pronounced than reported in former studies. In accordance with earlier studies we found a negative correlation between ZOBCR and OF volume. The ZOBCR decreases in relation to recent intake of a meal, probably because stimulated saliva production causes "dilution" of saliva. OF zopiclone concentration appeared unsuitable for estimation of blood zopiclone concentration. Due to long detection time, analysis of zopiclone in OF might be useful to detect non-recent, previous intake.

Acute Alcohol Use and Injury Patterns in Young Adult Prehospital Patients

The objective was to determine if acute alcohol consumption is associated with differences in injury pattern among young adult patients with traumatic injuries presenting to emergency medical services (EMS). A cross-sectional, retrospective review of prehospital patient care reports (PCRs) was conducted evaluating injured patients who presented to a collegiate EMS agency from January 1, 2011 to December 31, 2012. Included patients were age 18-24 y and sustained an injury within the previous 24 h. PCRs were reviewed independently by two abstractors to determine if the patient was documented to have acutely consumed alcohol proximate to his/her injury. Primary and secondary sites of regional body injury were recorded. Injury severity was recorded using the Revised Trauma Score (RTS). The association between primary injury site and acute alcohol use was assessed using a chi-square test. Multiple logistic regression was used to control for sex in predicting injury type. Of 440 injured patients, 135 (30.6%) had documented alcohol use prior to injury. Acute alcohol consumption altered the overall pattern of regional injury (p < 0.001). Alcohol users were more likely to present with injury secondary to assault, fall/trip, and unknown mechanism of injury (p < 0.001, all comparisons). RTS scores were statistically lower in the alcohol group (p < 0.001), although the clinical significance of this is unclear. Controlling for sex, acute alcohol consumption predicted increased risk of head/neck injury 5.59-fold (p < 0.001). Acute alcohol use in collegiate EMS patients appears to alter injury patterns in young adults and increases risk of head/neck injury. EMS providers in similar agencies should consider these trends when assessing and treating injured college-aged patients.

Individual psychomotor impairment in relation to zopiclone and ethanol concentrations in blood--a randomized controlled double-blinded trial

AIMS

To investigate individual traffic-relevant impairment related to measured blood zopiclone and ethanol concentrations. Also, we aimed to study possible development of acute tolerance.

DESIGN

A randomized controlled four-way cross-over double-blind trial. Study drugs were zopiclone 5 or 10 mg, 50 g ethanol or placebo.

SETTING

Laboratory study with computerized tests: Connor's Continuous Performance test, Choice Reaction Time and Stockings of Cambridge. Altogether, the tests consisted of 15 test components, representing three levels of behaviour (automotive, control, executive planning), relevant to traffic safety.

PARTICIPANTS

Sixteen healthy male volunteers.

MEASUREMENTS

Each study day, 10 blood samples were collected from each volunteer. Fifteen psychomotor test components were registered at baseline and a further three times after intake. Impairment was defined as any individual deterioration in performance compared to individual baseline performance.

FINDINGS

Blood drug concentrations up to 74 µg/l zopiclone and 0.100% ethanol were measured. We found a clear positive concentration-effect relationship for zopiclone and ethanol for both automotive and control behaviours, and a modest relationship for executive planning behaviour. Significant impairment started to be observed at concentrations above 16 µg/l zopiclone (automotive and control behaviour) and above 0.026% ethanol (automotive behaviour). Acute tolerance was found for both drugs.

CONCLUSIONS

The hypnotic, zopiclone, can impair psychomotor performance at blood concentrations as low as 16 µg/l.