The operation of a motor vehicle requires the integrity of sensory, motor, and intellectual faculties. Impairment of these faculties following the consumption of alcohol has been studied extensively through laboratory, closed-course and on-road driving, and epidemiological studies. The scientific literature was reviewed critically, with a focus on low-to-moderate blood alcohol concentrations (BAC ≤ 0.100%), to identify the most reliable determinants of alcohol-impaired driving. Variables such as age, gender, driving skill, and tolerance were shown to have limited impact on impairment. It was concluded the most relevant variables are BAC and complexity of the driving task. The scientific literature provides a high degree of confidence to support the conclusion that a BAC of 0.050% impairs faculties required in the operation of a motor vehicle. Whether impairment is apparent depends upon the complexity of the driving task, which applies to both study design and actual driving.

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A fatal concentration of pentobarbital found in a coroner's case where the history had not indicated use of this drug prompted a review of fatalities in Ontario from 2012 to 2015. Coroner's case files, including police and toxicology reports, were reviewed in twenty deaths, in which pentobarbital was identified as the primary cause of death. In all of the deaths (11 females, 9 males), the blood concentration of pentobarbital was greater than 10 mg/L. There were three to eight deaths per year and each was classified as suicide. In 11 cases, there was clear evidence that the drug was purchased over the internet from Mexico or China and imported into Canada. In four cases, it appears that the pentobarbital was labeled as a different, innocuous chemical to facilitate crossing the border without scrutiny. The findings underscore the value of a thorough scene investigation, including details of evidence that may be considered unrelated.

The proliferation of novel psychoactive substances (NPS) and the current opioid epidemic creates challenges for a toxicology laboratory. Methods capable of detecting and quantitating emerging compounds must be established despite limited information on toxicologically relevant concentrations. This paper will (1) describe how a publicly funded forensic laboratory reacted to the emergence of carfentanil as a public safety concern, and (2) contribute to the existing forensic literature by presenting a series of deaths involving carfentanil between July 2017 and June 2018. The Centre of Forensic Sciences is the primary provider of forensic toxicology testing in medicolegal death investigations in the province of Ontario. When carfentanil was first identified in the illicit drug supply, routine screening methods used by this laboratory were not sufficiently sensitive to detect the drug at concentrations expected in blood samples. Previously validated, multi-target LC–MS-MS quantitative methods already in use by the laboratory did show improved detectability for carfentanil. Thus, an existing LC–MS-MS method was adapted to include carfentanil; achieving improved sensitivity while also providing quantitation in suspected drug-related deaths. This approach had the added benefit that the LC–MS-MS method selected for modification was performed in all death investigations requiring toxicology analysis in Ontario, thereby providing an opportunity for surveillance. Using this method, 4953 cases were analyzed with carfentanil detected at a concentration greater than the limit of detection (0.05 ng/mL) in 160 decedents. Postmortem blood carfentanil concentrations ranged from less than 0.1 ng/mL to 9.2 ng/mL. Of the 160 carfentanil-positive cases, 156 were classified as either mixed drug toxicity or carfentanil overdose. The approach described enabled this laboratory to efficiently implement a quantitative test for carfentanil in all death investigations providing a useful template for modifying existing methods when a new psychoactive substance becomes available in the population.

The objective of this study was to investigate the correlation between CYP2D6 genotype, drug interactions, and morphine‐to‐codeine metabolic ratio (MR) in codeine‐related deaths (CRD). The records of the Office of the Chief Coroner of Ontario were examined to identify all CRD from 2006–2008. Deaths in which codeine and its metabolite, morphine, were quantified on the toxicological screen were included. From these, cases in which the manner of death was undetermined, heroin use was suspected, and/or morphine use was suspected were excluded. A total of 59 CRD were included. Postmortem blood samples were analyzed for 17 polymorphisms in CYP2D6 as well as gene duplication. The frequencies of CYP2D6 ultrarapid, extensive, intermediate, and poor metabolizer (PM) was not different in CRDs and a previously published healthy cohort taking opioids. Alcohol use prior to death was significantly associated with CRD that were deemed to be accidental by the coroner (p=0.05). The presence of a selective‐serotonin reuptake inhibitor was significantly associated with suicides (p=0.014). PM was associated with low MR. These findings suggest that CYP2D6 genotype and drug interactions should considered as part of the postmortem toxicological interpretation for CRD, especially in cases with low or high MR.