An investigation into the interaction between ethanol at low doses and the benzodiazepines nitrazepam and temazepam on psychomotor performance in normal subjects

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.

Comparative evaluation of aliskiren, ramipril, and losartan on psychomotor performance in healthy volunteers: A preliminary report

AIM

To compare the effects of aliskiren, ramipril, and losartan on the psychomotor performance in healthy volunteers.

MATERIALS AND METHODS

In this preliminary, single-dose, open-label, cross-over study conducted in 12 healthy volunteers, psychomotor assessment was carried out by four tests: Simple reaction time (SRT), multiple choice reaction time test (MCRT), critical flicker fusion frequency threshold test (CFFT), and tracking performance test (TPT). Each volunteer received a single dose of each of the three test drugs with a washout period of 10 days between different test sessions and then evaluated for post-drug scores at 2-h intervals up to 12 h and then at 24 h. The changes from the baseline scores by the test drug were statistically analyzed.

RESULTS

All the three antihypertensive drugs caused significant improvement in a similar fashion on SRT, MCRT calculated as error index, CFFT, and TPT. Aliskiren caused numerically more improvement than the other two test drugs, suggesting better cognitive profile. However, inter-drug comparisons were nonsignificant.

CONCLUSION

The results of the study highlight improvement of the cognitive functions equally by ramipril, losartan, and aliskiren. The results of the study could be of immense clinical utility in ambulatory hypertensive patients especially engaged in sensory-motor coordination tasks like driving and operating on mechanical tools.

Ethanol-diazepam interactions on delayed match-to-sample performance in baboons

Four juvenile male baboons were trained on a delayed match-to-sample (MTS) discrimination task. Single administration of 0.25, 0.5, 1.0, 2.0, 4.0, and 6.0 mg/kg diazepam (DZ) resulted in a dose-related increase in mean response time (MRT), with a maximum effect at 2.0 mg/kg. Administration of 0.25 mg/kg of DZ had no effect. Response time was increased significantly by 1.0 g/kg of ethanol (EtOH) but was not affected by 0.5 g/kg EtOH. There were no significant effects on the number of correct responses. Combined treatment of 0.5 g/kg of EtOH with 1.0 mg/kg DZ produced the same increase in MRT as the DZ alone. When 1.0 g/kg EtOH was administered with 0.25 mg/kg DZ. MRT decreased which was a significant improvement in performance as compared to the increase in MRT observed with either the EtOH or the DZ alone. Combined doses of 1.0 g/kg EtOH and 0.5 mg/kg DZ produced essentially the same increases in MRT as either dose alone. Similar results were obtained when 1.0 g/kg EtOH and 1.0 mg/kg DZ were combined and the increase in MRT was about the same for DZ alone and more than twice as great for the EtOH alone. Combined administration of the drugs had no significant effects on the number of correct choices. Since the administration of a combination of a low dose of DZ with EtOH appeared to prevent the increases in MRT observed with either drug alone and there were no observable effects on the number of correct response, these effects do not appear to involve cognitive processes but might be related to excitability changes in motor systems.

Effects of butoctamide hydrogen succinate and nitrazepam on psychomotor function and EEG in healthy volunteers

We studied the effects of butoctamide hydrogen succinate and nitrazepam on psychomotor function and EEG in eight male volunteers aged 19-32. The hypnotic effects, effects on psychomotor performance, EEG activity and standing steadiness between BAHS 1000 mg and nitrazepam 5 mg were compared at regular intervals for 10 h. The serum levels of both drugs were also assayed. The hypnotic effects of BAHS were very weak compared to those of nitrazepam. BAHS did not exert any effects on psychomotor performance and standing steadiness during the test period. In contrast, nitrazepam impaired psychomotor performance and standing steadiness as the serum drug levels increased. Nitrazepam decreased the alpha activity and increased the beta activity in a concentration-dependent manner. BAHS did not change the alpha activity but increased beta-2 activity at Fz and Cz at 10 h of the post-drug period. BAHS was eliminated more rapidly than nitrazepam. These results indicated that BAHS, at the dose used, was less potent than nitrazepam and the effects on psychomotor performance and standing steadiness were minimal.

Interactive effects of diazepam and ethanol on baboon match-to-sample performance

Four juvenile male baboons were trained to perform a match-to-sample (MTS) discrimination task. Diazepam (DZ) at doses of 0.5, 1.0, 2.0, 4.0, or 6.0 mg/kg resulted in a significant (p less than 0.05) increase in the mean response times (MRT) during the 2 hr test session in terms of percent change from baseline performance under nondrug conditions measured the day prior to drug treatment. Effects were maximal at 2.0 mg/kg diazepam and no further effects were observed at 4.0 or 6.0 mg/kg. Administration of 0.25 mg/kg of diazepam had no effect on MTS performance. Exposure to 0.5 g/kg of ethanol (EtOH) had no effect on response time, while 1.0 g/kg EtOH significantly (p less than 0.05) increased response time. Baboons receiving combined treatment with 0.5 or 1.0 g/kg EtOH plus 1.0 mg/kg diazepam displayed a significant (p less than 0.05) percent increase in mean response time compared to that observed under baseline conditions on the day prior to drug treatment. The 0.5 g/kg EtOH and 1.0 mg/kg diazepam combination increased MRT to an extent comparable to the effect observed at the same dose of diazepam alone. Effects observed with 1.0 mg/kg diazepam and 1.0 g/kg EtOH were similar to those produced by the DZ alone. Combinations of 0.5 g/kg EtOH and 0.5 mg/kg diazepam, 1.0 g/kg EtOH and 0.25 mg/kg diazepam, and 1.0 g/kg EtOH and 0.5 mg/kg diazepam had no significant effect on response times.(ABSTRACT TRUNCATED AT 250 WORDS)

Factors affecting the drinking driver

Although the relationship between alcohol and traffic safety has been the subject of numerous studies, much remains unknown about the mechanisms by which alcohol contributes to traffic accidents. A number of other factors, which are reviewed in this paper, also can contribute to car accidents. They may also interact with alcohol, perhaps in a complex manner. Therefore, multiple factors rather than one single factor may contribute to automobile accidents for those who drink and drive.

Tolerance to and cross-tolerance among ethanol, pentobarbital and chlordiazepoxide

The acute administration of ethanol, pentobarbital and chlordiazepoxide impaired, in a dose-dependent manner, the performance of rats on the moving-belt and two-way shuttle-box avoidance tests. Administration of these drugs for three weeks resulted in tolerance to their motor-impairing effects. Tolerance to ethanol or pentobarbital was characterized by a parallel shift of the dose-response curve to the right. Tolerance to chlordiazepoxide, however, was of greater extent and was accompanied by an apparent flattening of the dose-response curve. Symmetrical cross-tolerance developed between ethanol and pentobarbital. On the other hand, while chlordiazepoxide treatment conferred full cross-tolerance to ethanol and pentobarbital, only partial cross-tolerance to chlordiazepoxide was observed following treatment with ethanol or pentobarbital. These results suggest that at least part of the tolerance to chlordiazepoxide depends on changes in specific benzodiazepine receptors and is independent of the tolerance associated with non-specific changes in the cell membrane.