Drugs, pesticides and metabolites in forensic post-mortem blood samples

Acute, chronic, and post-mortem toxicity: a review focused on three different classes of new psychoactive substances

PURPOSE

New psychoactive substances (NPS) are not controlled under the Single Convention on Narcotic Drugs of 1961 or the 1971 Convention, but they may pose a public health threat. Knowledge of the main properties and toxicological effects of these substances is lacking. According to the current Drugs Law (Law n. 11.343/2006), the Brazilian Surveillance Agency issues directives for forbidden substances in Brazil, and structural classes of synthetic cannabinoids, cathinones, and phenylethylamines are considered illicit drugs. Considering that data on these controlled substances are scattered, the main objective of this work was to collect and organize data to generate relevant information on the toxicological properties of NPS.

METHODS

We carried out a literature review collecting information on the acute, chronic, and post-mortem toxicity of these classes of NSP. We searched info in five scientific databases considering works from 2017 to 2021 and performed a statistical evaluation of the data.

RESULTS

Results have shown a general lack of studies in this field given that many NPS have not had their toxicity evaluated. We observed a significant difference in the volume of data concerning acute and chronic/post-mortem toxicity. Moreover, studies on the adverse effects of polydrug use are scarce.

CONCLUSIONS

More in-depth information about the main threats involving NPS use are needed.

Ethanol and Medical Psychotropics Co-Consumption in European Countries: Results from a Three-Year Retrospective Study of Forensic Samples in Spain

Ethanol and medical psychotropics (MPs) are legal psychoactive substances widely consumed in Western countries that are routinely detected in standard toxicological analyses at compulsory autopsies, and toxicokinetic interactions between these drugs have been described. However, studies assessing the consequences of this co-consumption are scarce in Europe. We performed a retrospective study on toxicological results from compulsory autopsies in Spain. Thirty-five legal psychotropics, including ethanol, were measured in blood samples from 380 decedents to assess the determinants of such co-consumption. MPs were detected in 42.4% of the subjects. Polypharmacy was frequent in our series (25%), being more frequent in men than in women. More than one-third of the decedents had detectable levels of ethanol, and a significant positive association between ethanol levels and age was evident. About one-third of MPs consumers were also co-consumers of ethanol. The simultaneous consumption of ethanol and MPs was higher in men than in women. Blood alcohol concentrations (BAC) were lower in men who consumed MPs. In polypharmacy deaths, there was a significant negative association between the number of MPs consumed and BAC in men (r = -0.097; p = 0.029). Our results showed a high prevalence of co-consumption of MPs and ethanol in the European population involved in medico-legal issues and suggest that toxicokinetic interactions may be lowering BAC in men. This is a very worrying result, as it could indicate that the legal blood ethanol limits set by legislation would not be appropriate for men on MPs treatment.

Carbofuran self-poisoning: forensic and analytic investigations in twins and literature review

Carbofuran is a pesticide widely used in agricultural context to kill insects, mites, and flies by ingestion or contact. Along with literature review, we aimed to (i) present the clinical, autopsy, and toxicological findings of carbofuran self-poisonings in two 69-year-old twins, resulting in the death of one of them and (ii) assess carbofuran metabolite distribution using molecular networking. Quantitative analysis of carbofuran and its main metabolites (3-hydroxycarbofuran and 3-ketocarbofuran) was carried out using an original liquid chromatography-tandem mass spectrometry method on biological samples (cardiac or peripheral blood, urine, bile, and gastric contents). Toxicological analysis of post-mortem samples (twin 1) highlighted high concentrations of carbofuran and its metabolites in cardiac blood, bile, and gastric contents. These compounds were also quantified in blood and/or urine samples of the living brother (twin 2), confirming poisoning. Using molecular networking approach to facilitate visualization of mass spectrometry datasets and sample-to-sample comparisons, we detected two more metabolites (7-phenol-carbofuran and 3-hydroxycarbofuran glucuronide) in bile (twin 1) and urine (twin 2). These results highlight the value of (i) these compounds as carbofuran consumption markers and (ii) bile samples in post-mortem analysis to confirm poisoning. From an analytical point of view, molecular networking allowed the detection and interpretation of carbofuran metabolite ammonium adducts which helped to confirm their identification annotations, as well as their structural data. From a clinical point of view, the different outcomes between the two brothers are discussed. Overall, these cases provide novel information regarding the distribution of carbofuran and its metabolites in poisoning context.

Stimulant use in suicides: A systematic review

Suicide remains a global public health concern and the increased supply and use of synthetic stimulants globally may have implications for the burden of suicides attributable to substance use. This systematic review investigated any potential associations of stimulant use detected in post-mortem biological specimens and suicides. We conducted a systematic review and narrative synthesis (CRD42021237966). Medline, EMBASE, TOXLINE, and Scopus databases were searched for terms related to forensic toxicology, post-mortem toxicology, suicide and stimulants. The primary outcome was to estimate the prevalence of stimulant use in suicides. There were 26 studies whichcontributed to prevalence measures; in studies reporting at the individual compound level, suicides involved cocaine (0.1-23%), caffeine (3.2-22%), 3,4-methylenedioxymethamphetamine (0.1-17%), amphetamine (0.2-9.3%), methamphetamine (3.1-7%), and phentermine (0.9-1%). Overall, stimulant use in suicides was over-represented compared to estimates of stimulant use in the general population and has increased over time. Thirteen case reports used to contextualise suicides involving stimulants found no examples of cocaine or methamphetamine mono-intoxication of suicidal intent. This suggests mechanisms other than acute toxicity involved in stimulant-associated suicide. Future research by in-depth psychological autopsies of suicides involving stimulants, in combination with segmental hair analysis to determine the chronicity of stimulant exposure, may contribute to a better understanding of the burden of suicide attributable to stimulant use.

Psychoactive substances use before suicide: detailed analysis of all cases that occurred in the Brazilian Federal District in a 10-years period

BACKGROUND

Psychoactive substances (PASs) are an important risk factor for suicide. This study investigated the sociodemographic characteristics, data related to the suicidal behavior, the methods employed, the circumstances of the events, and the use of PASs before dying in all suicides that occurred between 2005-2014 in the Brazilian Federal District, comparing cases with positive and negative detection for PASs in the post-mortem analysis to identify groups at greatest risk.

METHODS

A population-based, observational, cross-sectional study with an analytical aspect was conducted with suicides cases collected from local police, which toxicological examination was performed (headspace gas chromatographic-mass spectrometry-HS-GC/MS) for detection of ethanol and methanol in blood samples; immunoassay for other substances (cocaine, marijuana, benzodiazepine).

RESULTS

The results showed that the increase in the suicide rate was 10 × greater than the population growth, and 44% of the individuals used PASs before suicide. Individuals are more likely to die by suicide at home, be male, have tried before, and change their behavior days before death; they choose to hang as the method and are influenced by alcohol.

CONCLUSION

Identifying what sociodemographic characteristics are associated with a fatal suicide attempt among individuals who use PASs and those who do not use and those who have/do not have mental disorders and what methods are employed could be employed as a path to better interventions. Thus, prevention actions could be planned and directed to individuals with greater risk.

Medical Psychotropics in Forensic Autopsies in European Countries: Results from a Three-Year Retrospective Study in Spain

Medical psychotropics are widely used and prescribed in developed countries. These medications may have an impairing effect on mood or perception and may induce harmful behaviors. Nevertheless, in Europe, studies on their importance from a medico-legal perspective are scarce. To fill this gap, we evaluate the determinants of these drugs in a retrospective study based on data obtained from forensic autopsies. Toxicological analyses were performed on 394 blood samples from compulsory autopsies at the Institute of Legal Medicine of Las Palmas. Of the samples, 41% (159) were positive for at least one psychotropic, with benzodiazepines being the most frequently detected (24.1%), followed by opiates and antidepressants. Benzodiazepines, opiates, and antidepressants were detected more frequently in men who suffered a violent death. More than 30% of the positive samples showed two or more drugs, suggesting a prevalence of polypharmacy among forensic autopsy subjects, with the most frequently combination found being benzodiazepines plus opiates (28.3% of positive samples). A combination of opiates plus antidepressants was also found in subjects involved in violent deaths. Our results suggest that more than 40% of the adult European population involved in medico-legal issues may be under the influence of legal psychotropics. The link between violent deaths and the use of medical psychotropics is particularly worrisome and indicates that these drugs should be carefully monitored in developed countries, in all forensic autopsies, in a similar way to illegal psychotropics.