Conversion factors for assessment of driving impairment after exposure to multiple benzodiazepines/z-hypnotics or opioids. (December 2017)

• Record Type: Journal Article
• Authors: Strand, Maren Cecilie; Mørland, Jørg; Slørdal, Lars; Riedel, Bettina; Innerdal, Cato; Aamo, Trond; Mathisrud, Grete; Vindenes, Vigdis
• Is Part Of: Forensic science international. Volume 281(2017)
• Page Start: 29
• Page End: 36
• Publication Date: 2017-12
• Subjects: Benzodiazepines -- Conversion factor -- DUI -- Legal limits -- Opioids -- Summarization; Medical jurisprudence -- Periodicals; Chemistry, Forensic -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Chimie légale -- Périodiques; Gerechtelijke geneeskunde; Gerechtelijke chemie; Gerechtelijke psychiatrie; Chemistry, Forensic; Medical jurisprudence; Electronic journals; Periodicals; Electronic journals; 614.1
• DOI: 10.1016/j.forsciint.2017.10.022
• Languages: English
• ISSNs: 0379-0738

Abstract

Highlights: Conversion factors were established to calculate diazepam and morphine equivalents. Concentrations of benzodiazepines/z-hypnotics and opioids converts to equivalents. Diazepam and morphine equivalents are summarized to assess impairment in DUI cases. Equivalence tables have been implemented in the Norwegian Road Traffic Act. Abstract: 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.