Forensic Sci Int. 2021 Nov 06;330:111097. doi: 10.1016/j.forsciint.2021.111097. Epub 2021 Nov 06.
Prevalence and concentrations of sedative-hypnotic drugs in blood of drivers involved in road traffic crashes in the Padova region of Italy - not so easy to interpret.
Forensic science international
Donata Favretto, Sindi Visentin, Alan W Jones
Affiliations
Affiliations
- University Hospital of Padova, Legal Medicine and Toxicology, Via Falloppio 50, Padova, Italy. Electronic address: [email protected].
- Polizia di Stato, Rome, Italy. Electronic address: [email protected].
- Division of Drug Research, Department of Biomedical and Clinical Sciences, Linköping University, SE-581 85 Linköping, Sweden. Electronic address: [email protected].
PMID: 34814082
DOI: 10.1016/j.forsciint.2021.111097
Abstract
BACKGROUND & OBJECTIVES: This study reports the prevalence and concentrations of sedative-hypnotic drugs as exemplified by benzodiazepines (BZD) and zolpidem (Z-hypnotic) in blood samples from drivers involved in road traffic accidents (RTA) in the Padova region of Italy. Another aim of the study was to estimate the prevalence of these drugs with concentrations in blood above the therapeutic intervals and above specific per se limits.
METHODS: A total of 4066 blood samples collected from drivers involved in RTA were analysed for the presence of alcohol, drugs of abuse and medicinal drugs with sedative-hypnotic properties. Prevalence of drivers positive for BZDs and zolpidem were reported according to the reporting limit of our laboratory (1 ng/mL) in a sort of zero tolerance approach and compared with the prevalence according to analytical cut-offs used in the "European Union's research project on Driving Under the Influence of Drugs, Alcohol and Medicines" (DRUID). The impairment-based, per se limits adopted in Norway and in England and Wales and the values used to define "therapeutic ranges" in blood and in plasma/serum were also applied to the case study.
RESULTS: 175 blood samples were positive for sedative-hypnotics above 1 ng/mL, with the following prevalence: diazepam 44%, nordazepam 41.8%, lorazepam 32.6%, zolpidem 28%, oxazepam 25.6%, alprazolam 16%, delorazepam 11,6%, lormetazepam 11,6%, temazepam 11.6%, clonazepam 11.6%, triazolam 6.9%, N-desalkylflurazepam 4.6%, bromazepam 2.3%. When applying DRUID analytical cut-offs, the prevalence of BZDs and zolpidem sharply decreases. Applying the impairing cut-offs used in Norway, 56% of positive samples were above the limits equivalent to a BAC of 0.2 g/L, 39% above the limits corresponding to 0.5 g/L, and 23% above the cut-off corresponding to 1.2 g/L. Only 1% of the drivers had drug concentrations above the per se concentration limits adopted in England and Wales [26]. When comparing blood levels with therapeutic ranges in plasma, bromazepam, lormetazepam and delorazepam were often found above the highest limits. The adjustment of the concentrations with the plasma-to-blood ratios causes a significant increase of cases above the therapeutic ranges in plasma.
CONCLUSIONS: Sedative-hypnotic drugs are medicinal substances frequently identified in drivers involved in RTA, commonly in concentrations associated with driving impairment. Besides the concentrations of drugs in blood, several factors have to be considered to conclude that a driver was impaired. The frequent association with alcohol, cocaine and other BZDs, confirms the abuse potential of these medications.
Copyright © 2021 Elsevier B.V. All rights reserved.
Keywords: Benzodiazepines; DUID; Impaired driving; Sedative-hypnotics; Traffic safety; Z-drugs
Conflict of interest statement
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this pa
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