Quetiapine-Related Deaths: In Search of a Surrogate Endpoint

Quetiapine is a second-generation antipsychotic drug available for two and half decades. Due to increased misuse, prescription outside the approved indications, and availability on the black market, it is being encountered in medicolegal autopsies more frequently. For instance, it has been linked to increased mortality rates, most likely due to its adverse effects on the cardiovascular system. Its pharmacokinetic features and significant postmortem redistribution challenge traditional sampling in forensic toxicology. Therefore, a systematic literature review was performed, inclusive of PubMed, the Web of Science-core collection, and the Scopus databases; articles were screened for the terms "quetiapine", "death", and "autopsy" to reevaluate each matrix used as a surrogate endpoint in the forensic toxicology of quetiapine-related deaths. Ultimately, this review considers the results of five studies that were well presented (more than two matrices, data available for all analyses, for instance). The highest quetiapine concentrations were usually measured in the liver tissue. As interpreted by their authors, the results of the considered studies showed a strong correlation between some matrices, but, unfortunately, the studies presented models with poor goodness of fit. The distribution of quetiapine in distinct body compartments/tissues showed no statistically significant relationship with the length of the postmortem interval. Furthermore, this study did not confirm the anecdotal correlation of peripheral blood concentrations with skeletal muscle concentrations. Otherwise, there was no consistency regarding selecting an endpoint for analysis.

Lethal vortioxetine poisoning? A forensic investigation

Vortioxetine is an antidepressant recently licensed in the US and EU for the treatment of major depressive disorder. No fatalities from vortioxetine overdose have been reported, yet. Two cases of attempted suicide are described in the literature, although no toxicological analyzes were conducted. Vortioxetine concentrations found in blood and organs in a case of a probable acute lethal intoxication are reported here. A 65-year-old woman was found on the floor behind her bed with no vital signs. The woman was recently on vortioxetine 10 mg/day for major depression, anxiety, and psychotic attacks. Vortioxetine was quantified in blood, brain, liver, kidney, and lung samples by LC-MS/MS. Vortioxetine concentrations were: 1.197 ng/ml in the blood, 804 ng/g in the brain, 8.992 ng/g in the lung, 1.389 ng/g in the liver, 292 in the kidney. No other substance was found. In the case reported here, the blood concentration was approximately 35-135 times higher than the antemortem therapeutic value. Histological examination showed signs of a probable sudden cardiac death following to arrhythmia, with no evidence of myocardial infarction. The present case indicate that blood concentrations close to 1,000 ng/mL could lead to death, involving probably to a cardiac toxicity.

Antipsychotic drug use complicates assessment of gene expression changes associated with schizophrenia

Recent postmortem transcriptomic studies of schizophrenia (SCZ) have shown hundreds of differentially expressed genes. However, the extent to which these gene expression changes reflect antipsychotic drug (APD) exposure remains uncertain. We compared differential gene expression in the prefrontal cortex of SCZ patients who tested positive for APDs at the time of death with SCZ patients who did not. APD exposure was associated with numerous changes in the brain transcriptome, especially among SCZ patients on atypical APDs. Brain transcriptome data from macaques chronically treated with APDs showed that APDs affect the expression of many functionally relevant genes, some of which show expression changes in the same directions as those observed in SCZ. Co-expression modules enriched for synaptic function showed convergent patterns between SCZ and some of the APD effects, while those associated with inflammation and glucose metabolism exhibited predominantly divergent patterns between SCZ and APD effects. In contrast, major cell-type shifts inferred in SCZ were primarily unaffected by APD use. These results show that APDs may confound SCZ-associated gene expression changes in postmortem brain tissue. Disentangling these effects will help identify causal genes and improve our neurobiological understanding of SCZ.

Comparison of serum and whole blood concentrations in quetiapine overdose cases

This study aimed to compare whole blood and serum concentrations of quetiapine in acute poisoning cases. Authentic whole blood and respective serum samples were routinely collected from patients diagnosed with blood poisoning at our University Hospital. Accordingly, whole blood and serum paired samples from nine patients (one male and eight female patients) were analyzed for quetiapine using liquid chromatography-mass spectrometry (LC-MS). Quetiapine concentrations in whole blood and serum samples ranged widely from 5.4 to 2780 ng/mL and 9.9 to 2500 ng/mL, respectively. The whole blood/serum concentration ratio was 0.5-1.1 and increased together with an increase in whole blood and serum quetiapine concentrations. The ratio was reversed at around 2500 ng/mL to > 1. Our findings suggest that whole blood concentrations are more useful than serum concentrations in diagnosing quetiapine poisonings.

Comparison of Comprehensive Screening Results in Postmortem Blood and Brain Tissue by UHPLC-QTOF-MS

Alternative specimens collected during autopsies can be valuable in postmortem toxicology in cases where peripheral blood is not available. The applicability of brain tissue as an alternative matrix for drug screening by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry was investigated in this study. Results of the 50 most frequently detected drugs and metabolites of toxicological interest in blood and brain tissue samples from 1,719 autopsy cases were compared. Examination of the results in paired blood and brain tissue samples revealed that the two matrices were in general comparable, as the majority of the 50 analytes were observed in a high number of the examined cases in both blood and brain tissue. This demonstrates the potential of brain tissue as an alternative matrix for drug screening in postmortem toxicology or as a secondary matrix for confirmation.

Quetiapine and other antipsychotics combined with opioids in legal autopsy cases: A random finding or cause of fatal outcome?

Opioid poisoning is a frequent cause of death in drug addicts and occurs with opioid treatment. Quetiapine is often found in forensic autopsies and may increase the risk of fatal opioid poisoning by enhancing sedation, respiratory depression, hypotension and QT prolongation. We systematically searched for studies of acute toxicity of quetiapine or other antipsychotics combined with morphine or methadone. Case reports describing toxicity of quetiapine combined with morphine or methadone were also included. We retrieved one human study that observed pharmacokinetic interaction between quetiapine and methadone, and 16 other human studies. Fourteen investigated the combination of droperidol and morphine in treatment doses, and some indicated an additive sedative effect. Five animal studies with acepromazine in combination with morphine or methadone were located and indicated an additive effect on sedation and hypotension. Six forensic case reports in which death could have been caused solely by quetiapine, the opioid, or other drugs were found. Thus, acute toxicity of quetiapine combined with morphine or methadone has not been studied. Because of quetiapine's effects on alpha-adrenoceptors, muscarinic and histamine receptors, human ether-a-go-go-channels and methadone kinetics, we suggest further research to clarify if the indicated additive effects of opioids and droperidol or acepromazine are also true for quetiapine.

The importance of sample size with regard to the robustness of postmortem reference values

Evaluating postmortem toxicological results is a challenging task due to multiple factors affecting blood concentrations after death. In order to improve the diagnostic accuracy in cases of suspected fatal intoxication different compilations of postmortem reference drug concentrations are often used. However, it is not clear what constitutes a reliable postmortem reference value. The current study presents reference concentrations for 13 substances from seven substance groups according to a standardized protocol. The reference concentrations were gathered from 3767 autopsy cases and subdivided into intoxications by one substance only (Group A, n=611), multi-substance intoxications (Group B, n=1355) and postmortem controls, in which incapacitation by drugs were excluded (Group C, n=1801). In particular, this study presents statistical information about the precision and conformity change with various sample sizes. Based on the present data >10 detections are usually needed, for the substances examined, to differentiate between intoxication cases and controls. Repeated samplings show that the median of small samples (N=≤5) has a high variation (normalized interquartile range 138-75%) and that a high number of detections (N=>20) in each group are needed to reduce the variation.

Quetiapine Poisoning and Factors Influencing Severity

PURPOSE/BACKGROUND

Quetiapine is a relatively new atypical antipsychotic with fewer adverse effects. It is increasingly prescribed to patients. The purpose of this study was to describe the cases of poisoning observed at the western France Poison Control Centre and identify potential risk factors that increase the severity of the cases.

METHODS

This was a retrospective study of self-poisoning with quetiapine as reported by the western France Poison Control Centre between 2007 and 2017.

RESULTS

There were 372 cases of quetiapine poisoning. Circumstances are known in 367 of 372 cases. There were 75 cases of null severity (grade 0), 133 cases of mild severity (grade 1), 85 cases of moderate severity (grade 2), and 79 cases of high severity (grade 3). Five deaths were listed in this series. The most commonly observed symptoms were neurological and cardiovascular in nature (drowsiness, coma, tachycardia, hypotension). Of these cases, 79.8% included voluntary ingestions. Among 302 cases with coagents, the most common coagents were benzodiazepines (56%), other psychotropic drugs (41%), and antidepressants (37%). An evaluated ingested dose 1500 mg or greater and 2 or more coagents increase the risk of severe poisoning. In particular, concomitant ingestion of benzodiazepines and antidepressants with quetiapine was associated with high severity (odds ratio, 2.478 [confidence interval, 1.3-4.723]; odds ratio, 1.820 [confidence interval, 1.010-3.316]).

CONCLUSIONS

Quetiapine may lead to severe poisoning for which there is currently no specific treatment. Patients and practitioners should be aware of this when quetiapine is prescribed, particularly when used in combination with other medications, and in order to deal with cases of poisoning.

A Validated Method for the Simultaneous Determination of Quetiapine, Clozapine and Mirtazapine in Postmortem Blood and Tissue Samples

Psychotropic drugs are regularly present in cases of sudden, unexpected death. Such drugs also tend to express significant postmortem redistribution. To facilitate further investigation of this phenomenon, reliable quantitative methods applicable to multiple biological matrices are needed. We present a validated ultra-performance liquid chromatography–tandem mass spectrometry method for the simultaneous quantification of quetiapine, clozapine and mirtazapine in postmortem whole blood, skeletal muscle, brain tissue and liver tissue using high-performance liquid chromatography–tandem mass spectrometry. Sample preparation was performed using liquid–liquid extraction. The validated ranges were 3.8–1534, 16–1960 and 13–1060 μg/L for quetiapine, clozapine and mirtazapine, respectively. Within-run and between-run accuracy (87.4–122%) and precision (CV 1.5–8.9%), matrix effects (95–101%) and recovery (35.7–92%) were validated at two concentration levels; 5.8 and 1227 μg/L for quetiapine, 25 and 1568 μg/L for clozapine and 20 and 849 μg/L for mirtazapine. Stability in a 10°C environment was assessed for treated samples of brain, liver and muscle tissue, showing deviations in analyte concentrations ranging from −8% to 9% after 3 days. The analyte concentrations in treated samples of whole blood stored at 4°C deviated by <5% after 5 days. The method was applied in three forensic autopsy cases implicating quetiapine, clozapine and mirtazapine, respectively, in supratherapeutic concentrations.

Distribution of Eight QT-Prolonging Drugs and Their Main Metabolites Between Postmortem Cardiac Tissue and Blood Reveals Potential Pitfalls in Toxicological Interpretation

Femoral blood concentrations are usually used in postmortem toxicology to assess possible toxic effects of drugs. This includes QT-prolongation and other cardiac dysrhythmia, which could have been the cause of death. However, blood concentration is only a surrogate for the active site concentration, and therefore cardiac tissue concentration may provide a more accurate toxicological interpretation. Thus, cardiac tissue and femoral and cardiac blood concentrations were examined for eight frequently used QT-prolonging drugs (QTD) and their metabolites in a mentally ill population. In total, 180 cases were included from the Danish autopsy-based forensic study SURVIVE. The concentrations were analyzed using ultra-performance liquid chromatography coupled with tandem mass spectrometry utilizing stable isotopically labeled internal standards. The results showed that the cardiac tissue concentrations were significantly higher compared to femoral and cardiac blood concentrations, with two exceptions. The median cardiac tissue-to-femoral blood concentration ratio (Kb) ranged from 2.2 (venlafaxine) to 15 (nortriptyline). The inter-individual fold difference between the minimum and maximum Kb ranged from 2.6-fold (Z-hydroxynortriptyline) to 61 (venlafaxine). For 12 compounds, postmortem redistribution appeared to be minimal, whereas four compounds displayed some degree of postmortem redistribution. Citalopram and quetiapine were selected for in-depth analysis of the relation between the toxicological interpretation and femoral blood/cardiac tissue concentrations. Within this dataset, citalopram displayed a wide overlap in cardiac tissue concentrations (~50%) between non-toxic and toxic citalopram cases, as estimated from femoral blood concentrations. In contrast, quetiapine displayed no overlap in cardiac tissue concentrations between non-toxic and toxic quetiapine cases based on femoral blood concentrations. The implication of the citalopram finding is that possible intoxications can be overlooked when only considering femoral blood concentrations. Based on the present findings, non-toxic cardiac tissue 10th-90th percentile concentration ranges were estimated for citalopram (0.93-4.4 mg/kg) and quetiapine (0.0073-0.60 mg/kg).

Reference Brain/Blood Concentrations of Citalopram, Duloxetine, Mirtazapine and Sertraline

Postmortem blood samples may not accurately reflect antemortem drug concentrations, as the levels of some drugs increase due to postmortem redistribution (PMR). The brain has been suggested as an alternative sampling site. The anatomically secluded site of the brain limits redistribution and prolongs the detection window, thereby enabling sampling from deceased individuals where blood is no longer suitable for analysis. We report concentrations in brain tissue and blood from 91 cases for the four antidepressants citalopram, duloxetine, mirtazapine and sertraline. The cases were classified according to their role in the cause of death, as follows: (A) concentrations where the drug was the sole cause of fatal intoxication; (B) concentrations where the drug contributed to a fatal outcome; and (C) concentrations where the drug was not related to the cause of death. The analytical method was successfully validated in brain tissue in terms of linearity, process efficiency, precision and accuracy. Quantification of analytes was performed by ultra-performance liquid chromatography with tandem mass spectrometry. Correlations between blood and brain concentrations were achieved with R2-values between 0.67 and 0.91. The following median brain-blood ratios were obtained: 3.71 for citalopram (range: 1.4-5.9), 11.0 for duloxetine (range: 5.0-21.6), 1.53 for mirtazapine (range: 1.02-4.71) and 7.38 for sertraline (range: 3.2-14.2). The S/R ratio of racemic citalopram was the same in brain (0.80) and blood (0.85), whereas the median citalopram/N-desmethylcitalopram ratio was higher in brain (9.1) than blood (4.1). The results of this study may serve as reference concentrations in brain for forensic cases.

Postmortem analysis of three methoxyacetylfentanyl-related deaths in Denmark and in vitro metabolite profiling in pooled human hepatocytes

Methoxyacetylfentanyl belongs to the group of fentanyl analogues and has been associated with several deaths in recent years. We present three case reports of deceased individuals that tested positive for methoxyacetylfentanyl consumption, as well as in vitro and in vivo metabolite profiles. Methoxyacetylfentanyl was quantified by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in femoral blood, as well as in urine and brain tissue when these were available. Metabolite profiling was performed by incubating methoxyacetylfentanyl with pooled human hepatocytes (pHH) in Leibovitz's L-15 medium supplemented with fetal bovine serum. Metabolites were identified in vivo and in vitro using UHPLC-high resolution (HR)-MS/MS. The measured methoxyacetylfentanyl concentration was 0.022-0.056mg/kg (N=3) in femoral blood, 0.12mg/kg (N=1) in urine, and 0.074mg/kg (N=1) in brain tissue homogenate. A total of 10 metabolites were identified. The observed metabolic pathways were: hydroxylation(s), N-dealkylation, O-demethylation, deamination, glucuronidation, and combinations thereof. Major analytical targets in vitro and across measured biological samples in vivo were methoxyacetylfentanyl, the O-demethyl- metabolite, and the deamide-metabolite. Intoxication with methoxyacetylfentanyl was judged as the cause of death or a major contributing factor in all three presented cases.

Abuse of Prescription Drugs in the Context of Novel Psychoactive Substances (NPS): A Systematic Review

Recently, a range of prescription and over-the-counter drugs have been reportedly used as Novel Psychoactive Substances (NPS), due to their potential for abuse resulting from their high dosage/idiosyncratic methods of self-administration. This paper provides a systematic review of the topic, focusing on a range of medications which have emerged as being used recreationally, either on their own or in combination with NPS. Among gabapentinoids, pregabalin may present with higher addictive liability levels than gabapentin, with pregabalin being mostly identified in the context of opioid, polydrug intake. For antidepressants, their dopaminergic, stimulant-like, bupropion activities may explain their recreational value and diversion from the therapeutic intended use. In some vulnerable clients, a high dosage of venlafaxine (‘baby ecstasy’) is ingested for recreational purposes, whilst the occurrence of a clinically-relevant withdrawal syndrome may be a significant issue for all venlafaxine-treated patients. Considering second generation antipsychotics, olanzapine appears to be ingested at very large dosages as an ‘ideal trip terminator’, whilst the immediate-release quetiapine formulation may possess proper abuse liability levels. Within the image- and performance- enhancing drugs (IPEDs) group, the beta-2 agonist clenbuterol (‘size zero pill’) is reported to be self-administered for aggressive slimming purposes. Finally, high/very high dosage ingestion of the antidiarrhoeal loperamide has shown recent increasing levels of popularity due to its central recreational, anti-withdrawal, opiatergic effects. The emerging abuse of prescription drugs within the context of a rapidly modifying drug scenario represents a challenge for psychiatry, public health and drug-control policies.

Is There a Potential of Misuse for Quetiapine?: Literature Review and Analysis of the European Medicines Agency/European Medicines Agency Adverse Drug Reactions' Database

PURPOSE/BACKGROUND

A recent years' increase in both prescribing and availability of second-generation antipsychotics (SGAs) has been observed. According to the literature, typically made up by case studies/series, quetiapine seems to be the most commonly misused SGA, with both intranasal and intravenous intake modalities having been described. Another SGA that has been anecdotally reported to be misused is olanzapine. For these molecules, both a previous history of drug misuse and being an inmate have been described as factors associated with misuse. Hence, while providing here an updated literature review of the topic, we aimed at assessing all cases of quetiapine misuse/abuse/dependence/withdrawal as reported to the European Medicines Agency's EudraVigilance (EV) database; this was carried out in comparison with the reference drug olanzapine.

METHODS

All spontaneous, European Medicines Agency database reports relating to both quetiapine (2005-2016) and olanzapine (2004-2016) misuse/abuse/dependence/withdrawal issues were retrieved, and a descriptive analysis was performed.

RESULTS

From the EV database, 18,112 (8.64% of 209,571) and 4178 (7.58% of 55,100) adverse drug reaction reports of misuse/abuse/dependence/withdrawal were associated with quetiapine and olanzapine, respectively. The resulting proportional reporting ratio values suggested that the misuse/abuse-, dependence-, and withdrawal-related adverse drug reactions were more frequently reported for quetiapine (1.07, 1.01, and 5.25, respectively) in comparison with olanzapine.

CONCLUSIONS

Despite data collection limitations, present EV data may suggest that, at least in comparison with olanzapine, quetiapine misuse may be a cause for concern.

Validation of a fully automated solid-phase extraction and ultra-high-performance liquid chromatography-tandem mass spectrometry method for quantification of 30 pharmaceuticals and metabolites in post-mortem blood and brain samples

In this study, we present the validation of an analytical method capable of quantifying 30 commonly encountered pharmaceuticals and metabolites in whole blood and brain tissue from forensic cases. Solid-phase extraction was performed by a fully automated robotic system, thereby minimising manual labour and human error while increasing sample throughput, robustness, and traceability. The method was validated in blood in terms of selectivity, linear range, matrix effect, extraction recovery, process efficiency, carry-over, stability, precision, and accuracy. Deuterated analogues of each analyte were used as internal standards, which corrected adequately for any inter-individual variability in matrix effects on analyte accuracy and precision. The lower limit of quantification (LLOQ) spanned from 0.0008 to 0.010 mg/kg, depending on the analyte, while the upper LOQ ranged between 0.40 and 2.0 mg/kg. Thus, the linear range covered both therapeutic and toxic levels. The method showed acceptable accuracy and precision, with accuracies ranging from 80 to 118% and precision below 19% for the majority of the analytes. Linear range, matrix effect, extraction recovery, process efficiency, precision, and accuracy were also tested in brain homogenate and the results agreed with those from blood. An additional finding was that the analyte concentrations in brain samples could be quantified by calibration curves obtained from spiked blood samples with acceptable precision and accuracy when using deuterated analogues of each analyte as internal standards. This method has been successfully implemented as a routine analysis procedure for quantification of pharmaceuticals in both blood and brain tissue since 2015.