Active metabolites as antidepressant drugs: the role of norquetiapine in the mechanism of action of quetiapine in the treatment of mood disorders

Effects of selective serotonin reuptake inhibitors on endocrine system (Review)

Selective serotonin reuptake inhibitors (SSRIs) are typically prescribed for treating major depressive disorder (MDD) due to their high efficacy. These drugs function by inhibiting the reuptake of serotonin [also termed 5-hydroxytryptamine (5-HT)], which raises the levels of 5-HT in the synaptic cleft, leading to prolonged activation of postsynaptic 5-HT receptors. Despite the therapeutic benefits of SSRIs, this mechanism of action also disturbs the neuroendocrine response. Hypothalamic-pituitary-adrenal (HPA) axis activity is strongly linked to both MDD and the response to antidepressants, owing to the intricate interplay within the serotonergic system, which regulates feeding, water intake, sexual drive, reproduction and circadian rhythms. The aim of the present review was to provide up-to-date evidence for the proposed effects of SSRIs, such as fluoxetine, citalopram, escitalopram, paroxetine, sertraline and fluvoxamine, on the endocrine system. For this purpose, the literature related to the effects of SSRIs on the endocrine system was searched using the PubMed database. According to the available literature, SSRIs may have an adverse effect on glucose metabolism, sexual function and fertility by dysregulating the function of the HPA axis, pancreas and gonads. Therefore, considering that SSRIs are often prescribed for extended periods, it is crucial to monitor the patient closely with particular attention to the function of the endocrine system.

Pharmacological Treatment of Fibromyalgia Syndrome: A Practice-Based Review

PURPOSE OF REVIEW

Fibromyalgia Syndrome (FMS) is a complex chronic pain condition characterized by widespread musculoskeletal pain and numerous other debilitating symptoms. The purpose of this review is to provide a comprehensive overview, based on everyday clinical practice, of the drugs presently employed in the treatment of FMS.

RECENT FINDINGS

The treatment of FMS is based on a multimodal approach, with pharmacologic treatment being an essential pillar. The drugs used include tricyclic antidepressants, serotonin and noradrenaline reuptake inhibitors, other antidepressants, anticonvulsants, myorelaxants, and analgesics. The effectiveness of these medications varies, and the choice of drug often depends on the specific symptoms presented by the patient. Many drugs tend to either address only some domains of the complex FMS symptomatology or have a limited effect on pain. Each treatment option comes with potential side effects and risks that necessitate careful consideration. It may be beneficial to divide patients into clinical subpopulations, such as FMS with comorbid depression, for more effective treatment. Despite the complexities and challenges, the pharmacological treatment remains a crucial part for the management of FMS. This review aims to guide clinicians in prescribing pharmacological treatment to individuals with FMS.

Gut microbial β-glucuronidases influence endobiotic homeostasis and are modulated by diverse therapeutics

Hormones and neurotransmitters are essential to homeostasis, and their disruptions are connected to diseases ranging from cancer to anxiety. The differential reactivation of endobiotic glucuronides by gut microbial β-glucuronidase (GUS) enzymes may influence interindividual differences in the onset and treatment of disease. Using multi-omic, in vitro, and in vivo approaches, we show that germ-free mice have reduced levels of active endobiotics and that distinct gut microbial Loop 1 and FMN GUS enzymes drive hormone and neurotransmitter reactivation. We demonstrate that a range of FDA-approved drugs prevent this reactivation by intercepting the catalytic cycle of the enzymes in a conserved fashion. Finally, we find that inhibiting GUS in conventional mice reduces free serotonin and increases its inactive glucuronide in the serum and intestines. Our results illuminate the indispensability of gut microbial enzymes in sustaining endobiotic homeostasis and indicate that therapeutic disruptions of this metabolism promote interindividual response variabilities.

Quetiapine improves sensorimotor gating deficit in a sleep deprivation-induced rat model

Background

Sleep deprivation (SD) impairs pre-stimulus inhibition, but the effect of quetiapine (QET) remains largely unknown.

Objective

This study aimed to investigate the behavioral and cognitive effects of QET in both naïve and sleep-deprived rats.

Materials and methods

Seven groups (n = 49) of male Wistar Albino rats were used in this study. SD was performed using the modified multiple platform technique in a water tank for 72 h. Our study consists of two experiments investigating the effect of QET on pre-pulse inhibition (PPI) of the acoustic startle reflex. The first experiment tested the effect of short- and long-term administration of QET on PPI response in non-sleeping (NSD) rats. The second experiment used 72 h REM sleep deprivation as a model for SD-induced impairment of the PPI response. Here, we tested the effect of QET on the % PPI of SD rats by short- and long-term intraperitoneal injection at the last 90 min of sleep SD and immediately subsequently tested for PPI.

Results

72 h SD impaired PPI, reduced startle amplitude, and attenuated the PPI% at + 4 dB, + 8 dB, and + 16 dB prepulse intensities. 10 mg/kg short and long-term QET administration completely improved sensorimotor gating deficit, increased startle amplitude, and restored the impaired PPI% at + 4 dB, + 8 dB, and + 16 dB after 72 h SD in rats.

Conclusion

Our results showed short- and long-term administration of QET improved sensorimotor gating deficit in 72 h SD. Further research is required for the etiology of insomnia and the dose-related behavioral effects of QET.

Pathogenesis and treatment of depression: Role of diet in prevention and therapy

In recent years, there has been a significant increase in depression, which is related to, among other things, the COVID-19 pandemic. Depression can be fatal if not treated or if treated inappropriately. Depression is the leading cause of suicide attempts. The disease is multifactorial, and pharmacotherapy often fails to bring satisfactory results. Therefore, increasingly more importance is attached to the natural healing substances and nutrients in food, which can significantly affect the therapy process and prevention of depressive disorders. A proper diet is vital to preventing depression and can be a valuable addition to psychological and pharmacologic treatment. An inadequate diet may reduce the effectiveness of antidepressants or increase their side effects, leading to life-threatening symptoms. This study aimed to review the literature on the pathogenesis of the development and treatment of depression, with particular emphasis on dietary supplements and the role of nutrition in the prevention and treatment of depressive disorders.

CYP3A4 and CYP3A5 Genotyping Recommendations: A Joint Consensus Recommendation of the Association for Molecular Pathology, Clinical Pharmacogenetics Implementation Consortium, College of American Pathologists, Dutch Pharmacogenetics Working Group of the Royal Dutch Pharmacists Association, European Society for Pharmacogenomics and Personalized Therapy, and Pharmacogenomics Knowledgebase

The goals of the Association for Molecular Pathology Clinical Practice Committee's Pharmacogenomics (PGx) Working Group are to define the key attributes of pharmacogenetic alleles recommended for clinical testing and a minimum set of variants that should be included in clinical PGx genotyping assays. This document series provides recommendations for a minimum panel of variant alleles (tier 1) and an extended panel of variant alleles (tier 2) that will aid clinical laboratories when designing assays for PGx testing. The Association for Molecular Pathology PGx Working Group considered functional impact of the variant alleles, allele frequencies in multiethnic populations, the availability of reference materials, and other technical considerations for PGx testing when developing these recommendations. The goal of this Working Group is to promote standardization of PGx gene/allele testing across clinical laboratories. This document will focus on clinical CYP3A4 and CYP3A5 PGx testing that may be applied to all CYP3A4- and CYP3A5-related medications. These recommendations are not to be interpreted as prescriptive but to provide a reference guide.

Quetiapine Treatment for Post-traumatic Stress Disorder: A Systematic Review of the Literature

Paroxetine and Sertraline are the only medications approved in posttraumatic stress disorder (PTSD). However, about 60% of traumatized patients fail to show an adequate clinical response. Second generation antipsychotics are recommended as second-line monotherapy or third-line augmentation strategies and quetiapine appears as one of the most used and promising agents. Up to date, no reviews assessed the efficacy of quetiapine in the treatment of PTSD. We aimed to assess the effectiveness and general safety of quetiapine on PTSD. A systematic review was conducted following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Cochrane guidelines, selecting studies that evaluated the efficacy of quetiapine on global or specific PTSD symptomatology. Ten studies (n = 894) were considered eligible for qualitative synthesis: one case report, one case series, one prospective cohort study, 3 open-label trials, 3 retrospective studies, one randomized controlled trial. Quetiapine was effective on global PTSD symptomatology assessed in 6 studies as well as on re-experiencing (4/4 studies), avoidance (4/3 studies) and hyperarousal (4/4 studies), flashbacks (2/2 studies), depressive (4/4 studies), anxiety (1/1 studies), psychotic (3/3 studies), insomnia (4/5 studies), nightmares (3/3 studies) specific symptoms and PTSD domains. Sedation was among the most frequently observed adverse effects and the main cause of drug discontinuation. Preliminary findings support the efficacy of quetiapine in ameliorating symptoms relative to PTSD and its overall safety. However, quetiapine use in PTSD cannot be recommended yet as studies mainly rely on open-label, retrospective studies or case series.

Dose-Dependent Biphasic Action of Quetiapine on AMPK Signalling via 5-HT7 Receptor: Exploring Pathophysiology of Clinical and Adverse Effects of Quetiapine

Recent pharmacological studies indicated that the modulation of tripartite-synaptic transmission plays important roles in the pathophysiology of schizophrenia, mood disorders and adverse reactions. Therefore, to explore the mechanisms underlying the clinical and adverse reactions to atypical antipsychotics, the present study determined the effects of the sub-chronic administration of quetiapine (QTP: 3~30 μM) on the protein expression of 5-HT7 receptor (5-HT7R), connexin43 (Cx43), cAMP level and intracellular signalling, Akt, Erk and adenosine monophosphate-activated protein kinase (AMPK) in cultured astrocytes and the rat hypothalamus, using ultra-high-pressure liquid chromatography with mass spectrometry and capillary immunoblotting systems. QTP biphasically increased physiological ripple-burst evoked astroglial D-serine release in a concentration-dependent manner, peaking at 10 μM. QTP enhanced the astroglial signalling of Erk concentration-dependently, whereas both Akt and AMPK signalling’s were biphasically enhanced by QTP, peaking at 10 μM and 3 μM, respectively. QTP downregulated astroglial 5-HT7R in the plasma membrane concentration-dependently. Protein expression of Cx43 in astroglial cytosol and intracellular cAMP levels were decreased and increased by QTP also biphasically, peaking at 3 μM. The dose-dependent effects of QTP on the protein expression of 5-HT7R and Cx43, AMPK signalling and intracellular cAMP levels in the hypothalamus were similar to those in astrocytes. These results suggest several complicated pharmacological features of QTP. A therapeutically relevant concentration/dose of QTP activates Akt, Erk and AMPK signalling, whereas a higher concentration/dose of QTP suppresses AMPK signalling via its low-affinity 5-HT7R inverse agonistic action. Therefore, 5-HT7R inverse agonistic action probably plays important roles in the prevention of a part of adverse reactions of QTP, such as weight gain and metabolic complications.

Antipsychotic prescription patterns and associated factors among the elderly with psychiatric illnesses

Prescribing rate of antipsychotics in elderly patients with psychiatric illnesses has been increasing all over the world. However, there is a lack of research examining the use of antipsychotics at psychiatric hospitals. We aim to find out long-term trends in antipsychotic prescriptions and factors associated with the use of antipsychotics in the elderly population. All outpatient visits with patients aged over 65 years between 2006 and 2015 in a psychiatric hospital were included in the analysis. Demographic and clinical data, including patient age, sex, National Health Insurance status, psychiatric diagnosis and antipsychotic prescription, were retrieved through the electronic medical information system. In this study, we found that prescribing rate of antipsychotics has increased around 5.07% through the study period (from 57.25% in 2006 to 60.15% in 2015, P < 0.001). Among all antipsychotics, there was an increase in the use of second-generation antipsychotics with a simultaneous decline in the use of first-generation antipsychotics. Logistic regression analysis showed advanced age, female gender and certification for catastrophic illnesses were positively associated with the use of antipsychotics. Furthermore, patients most likely to be prescribed an antipsychotic were those with psychotic disorders, followed by dementia, and then affective or neurotic disorders. The results of this study were consistent with the worldwide trend of increasing prescriptions of second-generation antipsychotics among elderly patients with psychiatric illnesses. Despite the potential benefits of these medications on certain psychiatric symptoms, clinicians need to exercise due caution as they may also cause potentially serious side effects among the elderly population.

Brexpiprazole Reduces 5-HT7 Receptor Function on Astroglial Transmission Systems

Several atypical antipsychotics exert mood-stabilising effects via the modulation of various monoamine receptors and intracellular signallings. Recent pharmacodynamic studies suggested that tripartite synaptic transmission can contribute to the pathophysiology of schizophrenia and mood disorders, their associated cognitive impairment, and several adverse reactions to atypical antipsychotics. Therefore, to explore the mechanisms underlying the antidepressive mood-stabilising and antipsychotic effects of brexpiprazole (Brex), we determined the effects of subchronic administration of therapeutically relevant concentrations/doses of Brex on the protein expression of 5-HT receptors, connexin43, cAMP levels, and intracellular signalling in cultured astrocytes and rat hypothalamus using ultra-high-pressure liquid chromatography with mass spectrometry and capillary immunoblotting systems. Subchronic administration of a therapeutically relevant concentration of Brex (300 nM) downregulated both 5-HT1A (5-HT1AR) and 5-HT7 (5-HT7R) receptors, in addition to phosphorylated Erk (pErk), without affecting phosphorylated Akt in the astroglial plasma membrane. Subchronic administration of 300 nM Brex decreased and increased phosphorylated AMPK and connexin43, respectively, in the astroglial cytosol fraction. A therapeutically relevant concentration of Brex acutely decreased the astroglial cAMP level, whereas, under the inhibition of 5-HT1AR, Brex did not affect astroglial cAMP levels. However, the 5-HT7R-agonist-induced increased astroglial cAMP level was inhibited by Brex. In contrast to the in vitro study, systemic subchronic administration of effective doses of Brex (3 and 10 mg/kg/day for 14 days) increased the cAMP level but did not affect phosphorylated AMPK in the rat hypothalamus. These results suggest several complicated pharmacological features of Brex. Partial 5-HT1AR agonistic action predominates in the low range of therapeutically relevant concentrations of Brex, whereas in the high range, 5-HT7R inverse agonist-like action is overlapped on the 5-HT1A agonistic action. These unique suppressive effects of Brex on 5-HT7R play important roles in the clinical features of Brex regarding its antidepressive mood-stabilising actions.

The Atypical Antipsychotic Quetiapine Promotes Multiple Antibiotic Resistance in Escherichia coli

Atypical antipsychotic (AAP) medication is a critical tool for treating symptoms of psychiatric disorders. While AAPs primarily target dopamine (D2) and serotonin (5HT2A and 5HT1A) receptors, they also exhibit intrinsic antimicrobial activity as an off-target effect. Because AAPs are often prescribed to patients for many years, a potential risk associated with long-term AAP use is the unintended emergence of bacteria with antimicrobial resistance (AMR). Here, we show that exposure to the AAP quetiapine at estimated gut concentrations promotes AMR in Escherichia coli after 6 weeks. Quetiapine-exposed isolates exhibited an increase in MICs for ampicillin, tetracycline, ceftriaxone, and levofloxacin. By whole-genome sequencing analysis, we identified mutations in genes that confer AMR, including the repressor for the multiple antibiotic resistance mar operon (marR), and real-time reverse transcription-quantitative PCR (RT-qPCR) analysis showed increased levels of marA, acrA, and tolC mRNAs and reduced levels of ompF mRNA in the isolates carrying marR mutations. To determine the contribution of each marR mutation to AMR, we constructed isogenic strains carrying individual mutant marR alleles in the parent background and reevaluated their resistance phenotypes using MIC and RT-qPCR assays. While marR mutations induced robust activity of the mar operon, they resulted in only modest increases in MICs. Interestingly, although these marR mutations did not fully recapitulate the AMR phenotype of the quetiapine-exposed isolates, we show that marR mutations promote growth fitness in the presence of quetiapine. Our findings revealed an important link between the use of AAPs and AMR development in E. coli. IMPORTANCE AAP medication is a cornerstone in the treatment of serious psychiatric disease. The AAPs are known to exhibit antimicrobial activity; therefore, a potential unintended risk of long-term AAP use may be the emergence of AMR, although such risk has received little attention. In this study, we describe the development of multidrug antibiotic resistance in Escherichia coli after 6 weeks of exposure to the AAP quetiapine. Investigation of mutations in the marR gene, which encodes a repressor for the multiple antibiotic resistance (mar) operon, reveals a potential mechanism that increases the fitness of E. coli in the presence of quetiapine. Our findings establish a link between the use of AAPs and AMR development in bacteria.

Dopamine D1- and D2-like receptors oppositely regulate lifespan via a dietary restriction mechanism in Caenorhabditis elegans

BACKGROUND

Despite recent progress in understanding the molecular mechanisms regulating aging and lifespan, and the pathways involved being conserved in different species, a full understanding of the aging process has not been reached. In particular, increasing evidence suggests an active role for the nervous system in lifespan regulation, with sensory neurons, as well as serotonin and GABA signaling, having been shown to regulate lifespan in Caenorhabditis elegans (C. elegans). However, the contribution of additional neural factors, and a broad understanding of the role of the nervous system in regulating aging remains to be established. Here, we examine the impact of the dopamine system in regulating aging in C. elegans.

RESULTS

We report that mutations of DOP-4, a dopamine D1-like receptor (D1R), and DOP-2, a dopamine D2-like receptor (D2R) oppositely affected lifespan, fast body movement span, reproductive lifespan, and developmental rate in C. elegans. Activation of D2R using aripiprazole, an antipsychotic drug, robustly extended both lifespan and healthspan. Conversely, inhibition of D2R using quetiapine shortened worm lifespan, further supporting the role of dopamine receptors in lifespan regulation. Mechanistically, D2R signaling regulates lifespan through a dietary restriction mechanism mediated by the AAK-2-DAF-16 pathway. The DAG-PKC/PKD pathway links signaling between dopamine receptors and the downstream AAK-2-DAF-16 pathway to transmit longevity signals.

CONCLUSIONS

These data demonstrated a novel role of dopamine receptors in lifespan and dietary restriction regulation. The clinically approved antipsychotic aripiprazole holds potential as a novel anti-aging drug.

Tools for optimising pharmacotherapy in psychiatry (therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests): focus on antidepressants

Objectives: More than 40 drugs are available to treat affective disorders. Individual selection of the optimal drug and dose is required to attain the highest possible efficacy and acceptable tolerability for every patient.Methods: This review, which includes more than 500 articles selected by 30 experts, combines relevant knowledge on studies investigating the pharmacokinetics, pharmacodynamics and pharmacogenetics of 33 antidepressant drugs and of 4 drugs approved for augmentation in cases of insufficient response to antidepressant monotherapy. Such studies typically measure drug concentrations in blood (i.e. therapeutic drug monitoring) and genotype relevant genetic polymorphisms of enzymes, transporters or receptors involved in drug metabolism or mechanism of action. Imaging studies, primarily positron emission tomography that relates drug concentrations in blood and radioligand binding, are considered to quantify target structure occupancy by the antidepressant drugs in vivo. Results: Evidence is given that in vivo imaging, therapeutic drug monitoring and genotyping and/or phenotyping of drug metabolising enzymes should be an integral part in the development of any new antidepressant drug.Conclusions: To guide antidepressant drug therapy in everyday practice, there are multiple indications such as uncertain adherence, polypharmacy, nonresponse and/or adverse reactions under therapeutically recommended doses, where therapeutic drug monitoring and cytochrome P450 genotyping and/or phenotyping should be applied as valid tools of precision medicine.

Variants in COMT, CYP3A5, CYP2B6, and ABCG2 Alter Quetiapine Pharmacokinetics

Quetiapine is an atypical antipsychotic widely used for the treatment of schizophrenia and the depressive episodes of bipolar disorder. The aim of this work was to investigate the effect of variants in relevant pharmacogenes in the pharmacokinetics of quetiapine and to exploratorily evaluate adverse drug reaction (ADR) incidence based on genetic polymorphism. Specifically, 49 healthy volunteers enrolled in two bioequivalence clinical trials were included in this study. In addition, 80 variants in 19 relevant pharmacogenes were genotyped, including cytochrome P450 (CYP) genes, catechol-O-methyl transferase (COMT), other enzymes (e.g., UGT1A1 or UGT1A4), and transporters (e.g., SLCO1B1, ABCB1, or ABCG2). The COMT rs13306278 T allele was significantly related to quetiapine-increased exposure. We demonstrated the existence of quetiapine derivatives with a catechol-like structure (7,8-dihydroxi-quetiapine and 7,8-dihydroxi-N-desalkyl-quetiapine), which would be COMT metabolites and would explain quetiapine accumulation through CYP2D6 and CYP3A4 negative feedback. Moreover, CYP3A5 and CYP2B6 phenotypes were related to quetiapine exposure variability, which confirms (for CYP3A5) and suggests (for CYP2B6) that these enzymes play an important role in quetiapine’s metabolism. Finally, the ABCG2 rs2231142 T allele was related to quetiapine accumulation. Further studies are required to confirm the clinical relevance of our findings.

Biologically active metabolites in drug discovery

Biologically active metabolites are a valuable resource for development of drug candidates and lead structures for drug design. This digest highlights a selection of biologically active metabolites that have been used as new chemical entities for development or as lead structures for drug design.

Association of the neutrophil to lymphocyte ratio and white blood cell count with response to pharmacotherapy in unipolar psychotic depression: An exploratory analysis

Background

Low-grade inflammation occurs in a subgroup of patients with Major Depressive Disorder (MDD) and may be associated with response to antidepressant medications. The Neutrophil to Lymphocyte Ratio (NLR) and total White Blood cell Count (WBC) are markers of systemic inflammation which have not been investigated as predictors for outcome to pharmacotherapy in unipolar depression yet. Moreover, the association between inflammation and treatment response has not been studied in unipolar Psychotic Depression (PD). We conducted an exploratory analysis to examine the prognostic significance of NLR and WBC in pharmacotherapy of PD.

Methods

Baseline NLR and WBC were examined in their association with response to seven weeks of treatment with antidepressants (venlafaxine or imipramine) and the combination of an antidepressant with an antipsychotic (venlafaxine plus quetiapine) in 87 patients with PD. Logistic regression models were adjusted for age, gender, Body Mass Index (BMI), depression severity, duration of the current episode and number of previous depressive episodes. Secondary outcomes were remission of depression and disappearance of psychotic symptoms.

Results

Higher NLR was associated with increased response to pharmacotherapy (Exp(B) 1.66, 95 ​% CI 1.03–2.66, p ​= ​0.036), but not with remission of depression or disappearance of psychotic symptoms. WBC was not associated with any of the outcome measures.

Conclusion

NLR may be a novel, inexpensive and widely available biomarker associated with response to pharmacotherapy in PD. The association between white blood cell measures and treatment outcome should be further investigated for different types of antidepressants in PD and in non-psychotic MDD.

Bibliometrics and Visual Analysis of the Research Status and Trends of Postpartum Depression From 2000 to 2020

The purpose of this study was to evaluate the international scientific output on postpartum depression (PPD) research during 2000–2020 through a bibliometric analysis and to explore research hotspots, frontiers, and trends in the field of postpartum depression. We searched the Web of Science Core Collection for publications on postpartum depression published between 2000 and 2020. CiteSpace, gCluto, and other software applications were used to analyze the data by year, journal, and country. A total of 2,963 publications were retrieved and 96 countries or regions published related papers. The United States had the largest number of published papers and the highest betweenness centrality, which is the dominant position in the field of postpartum depression. A total of 717 journals published papers, with the Archives of Womens Mental Health ranked first in terms of volume and betweenness centrality. In this study, 31 high-frequency main MeSH terms/subheadings were selected. The high-frequency MeSH terms were clustered into six categories: an overview of depression-related research, diagnostic and screening scales for postpartum depression, epidemiological investigation into postpartum depression, treatment and drug selection for postpartum depression, psychological research on postpartum depression, and etiology, physiopathology, complications, genetics of postpartum depression. Finally, we used strategic diagram to analyze research trends in postpartum depression. This study has identified a continuous significant increase in the publication of PPD articles. Currently, the etiology, physiological pathology, intervention and treatment of complications on PPD are immature, which provides reference for the trend of obstetric psychology.

Proposal for fluorescence-based in vitro assay using human and zebrafish monoamine transporters to detect biological activities of antidepressants in wastewater

Antidepressants are among the most commonly detected pharmaceuticals in the aquatic environment. As they modulate neurotransmission in nervous systems, behavioural abnormalities among aquatic species are of concern. It is possible to measure the concentrations of selected antidepressants by chemical analysis, but other non-target antidepressants and active metabolites might also be present. Here, we propose an "in vitro monoamine transporter inhibition assay" to measure the biological activity of antidepressants, particularly monoamine transporter inhibitors, in wastewater. We used APP, a fluorescent substrate for monoamine transporters, to measure the activity of wastewater extracts at inhibiting APP uptake through the human serotonin transporter (hSERT), norepinephrine transporter (hNET), and dopamine transporter, and the zebrafish SERT (zSERT). We confirmed that the assay could measure the biological activity of test antidepressants. Interestingly, the IC₅₀ values of antidepressants (the concentration that gave a 50% reduction of APP uptake) for the zSERT were smaller than those for the hSERT. For example, IC₅₀ value of desipramine for the zSERT was 1/200 of that for the hSERT. These results indicate that antidepressants inhibited zSERT more strongly than hSERT. Then we applied the assay to extracts of effluent from municipal wastewater treatment plants and detected biological activity of antidepressants specifically against the hSERT, hNET, and zSERT for the first time. For the hSERT, antidepressant-equivalent quantities (EQs) ranged from 2.2 × 10¹ to 2.5 × 10² ng-clomipramine-EQ/L. For the hNET, EQs ranged from below limit of detection to 8.2 × 10¹ ng-desipramine-EQ/L. For the zSERT, EQs ranged from 2.8 × 10² to 3.3 × 10² ng-duloxetine-EQ/L. The in vitro monoamine transporter inhibition assay is thus useful for measuring the biological activity of antidepressants in the aquatic environment.

Psychoactive Medication, Violence, and Variant Alleles for Cytochrome P450 Genes

From the start of the use of psychoactive prescription medications in the 1950s, physicians reported paradoxical adverse reactions, ranging from newly developing depressions to an increase in existing mood disorders, and extremely violent and bizarre acts of suicide and homicide. It is hypothesized that interactions between the drugs and the enzymes that are primarily responsible for their metabolism (cytochrome P450s) could cause these reactions. In this research, we evaluate statistical associations between CYP450 variant alleles, psychoactive medication, and acts of violence. Fifty-five persons who showed violent behavior or an altered emotional state were investigated for prescribed medication. Fifty-eight volunteers with no history of violence served as the controls. Genetic testing was performed on CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A4. Statistical analysis was applied to gender, age, number of variant alleles, number and kind of medications, and potential drug-drug, drug-gene, and drug-drug-gene interactions. Four risk factors for developing an altered emotional state and/or acts of violence were identified. There is an association between prescription drugs (most notably antidepressants and other psychoactive medication), having variant alleles for CYP450 genes, and altered emotional states or acts of violence.

β2 and α2 adrenergic receptors mediate the proneurogenic in vitro effects of norquetiapine

Positive modulation of adult hippocampal neurogenesis may contribute to the therapeutic effects of clinically relevant antidepressant drugs, including atypical antipsychotics. Quetiapine, an antipsychotic which represents a therapeutic option in patients who are resistant to classical antidepressants, promotes adult hippocampal neurogenesis in preclinical studies. Norquetiapine, the key active metabolite of quetiapine in humans, has a distinctive receptor profile than the parent compound. The drug is indeed a high affinity norepinephrine transporter inhibitor and such activity has been proposed to contribute to its antidepressant effect. At present, no information is available on the effects of norquetiapine on adult neurogenesis. We extensively investigated the activity of quetiapine and norquetiapine on adult murine neural stem/progenitor cells and their progeny. Additionally, selective antagonists for β₂/α₂ adrenergic receptors allowed us to evaluate if these receptors could mediate quetiapine and norquetiapine effects. We demonstrated that both drugs elicit in vitro proneurogenic effects but also that norquetiapine had distinctive properties which may depend on its ability to inhibit norepinephrine transporter and involve β₂/α₂ adrenergic receptors. Animal care and experimental procedures were approved by the Institutional Animal Care and Use Committees (IACUC) at University of Piemonte Orientale, Italy (approval No. 1033/2015PR) on September 29, 2015.

Current Limitations and Candidate Potential of 5-HT7 Receptor Antagonism in Psychiatric Pharmacotherapy

Several mood-stabilizing atypical antipsychotics and antidepressants weakly block serotonin (5-HT) receptor type-7 (5-HT7R); however, the contributions of 5-HT7R antagonism to clinical efficacy and pathophysiology are yet to be clarified. A novel mood-stabilizing antipsychotic agent, lurasidone exhibits predominant binding affinity to 5-HT7R when compared with other monoamine receptors. To date, we have failed to discover the superior clinical efficacy of lurasidone on schizophrenia, mood, or anxiety disorders when compared with conventional mood-stabilizing atypical antipsychotics; however, numerous preclinical findings have indicated the possible potential of 5-HT7R antagonism against several neuropsychiatric disorders, as well as the generation of novel therapeutic options that could not be expected with conventional atypical antipsychotics. Traditional experimental techniques, electrophysiology, and microdialysis have demonstrated that the effects of 5-HT receptor type-1A (5-HT1AR) and 5-HT7R on neurotransmission are in contrast, but the effect of 5-HT1AR is more predominant than that of 5-HT7R, resulting in an insufficient understanding of the 5-HT7R function in the field of psychopharmacology. Accumulating knowledge regarding the pharmacodynamic profiles of 5-HT7R suggests that 5-HT7R is one of the key players in the establishment and remodeling of neural development and cytoarchitecture during the early developmental stage to the mature brain, and dysfunction or modulation of 5-HT7R is linked to the pathogenesis/pathophysiology of neuropsychiatric and neurodevelopmental disorders. In this review, to explore candidate novel applications for the treatment of several neuropsychiatric disorders, including mood disorders, schizophrenia, and other cognitive disturbance disorders, we discuss perspectives of psychopharmacology regarding the effects of 5-HT7R antagonism on transmission and intracellular signaling systems, based on preclinical findings.

Norquetiapine blocks the human cardiac sodium channel Nav1.5 in a state-dependent manner

Quetiapine, an atypical antipsychotic drug, is used for the treatment of schizophrenia and acute mania. Although a previous report showed that quetiapine blocked hERG potassium current, quetiapine has been considered relatively safe in terms of cardiovascular side effects. In the present study, we used the whole-cell patch-clamp technique to investigate the effect that quetiapine and its major metabolite norquetiapine can exert on human cardiac sodium channels (hNa_v1.5). The half-maximal inhibitory concentrations of quetiapine and norquetiapine at a holding potential of -90 mV near the resting potential of cardiomyocytes were 30 and 6 μM, respectively. Norquetiapine as well as quetiapine was preferentially bound in the inactivated state of the hNa_v1.5 channel. Norquetiapine slowed the recovery from inactivation of hNa_v1.5 and consequently induced strong use-dependent inhibition. Our results indicate that norquetiapine blocks hNa_v1.5 current in concentration-, state- and use-dependent manners, suggesting that the blockade of hNa_v1.5 current by norquetiapine may shorten the cardiac action potential duration and reduce the risk of QT interval prolongation induced by the inhibition of hERG potassium currents.

Efficacy and Safety of Quetiapine for Pediatric Bipolar Depression: A Systematic Review of Randomized Clinical Trials

Quetiapine is a second-generation antipsychotic (SGA) approved by the Food and Drug Administration (FDA) for the treatment of schizophrenia, mania, and aggression in children and adolescents. It is also commonly used as an off-label medication to treat children and adolescents with bipolar depression, although the FDA has not approved quetiapine for this purpose. We conducted a systematic review of randomized clinical trials (RCTs) using the MEDLINE database and included two studies that met our inclusion criteria. Both RCTs were eight-week short-term studies that involved patients of 10-18 years of age with a Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) diagnosis of bipolar disorder, depressed type. The mean difference in the Children's Depression Rating Scale-Revised (CDRS-R) score and the response and remission rates in the quetiapine group were not statistically significant when compared to the placebo group. A high placebo response rate proved that quetiapine was no better than the placebo in treating pediatric bipolar depression. Quetiapine proved to be a relatively safe drug with the most common side effects being headache, somnolence, gastric upset, and weight gain. There was a significant increase in triglyceride levels, but no other metabolic effects were reported. This calls for future studies with larger sample sizes and improved methodology to explore the efficacy of quetiapine and other SGAs for the management of pediatric bipolar depression.

Immunoendocrine Peripheral Effects Induced by Atypical Antipsychotics

Atypical antipsychotics (AAP) or second-generation antipsychotics are the clinical option for schizophrenia treatment during acute psychoses, but they are also indicated for maintenance during lifetime, even though they are being used for other psychiatric conditions in clinical practice such as affective disorders and autism spectrum disorder, among others. These drugs are differentiated from typical antipsychotics based on their clinical profile and are a better choice because they cause fewer side effects regarding extrapyramidal symptoms (EPS). Even though they provide clear therapeutic benefits, AAP induce peripheral effects that trigger phenotypic, functional, and systemic changes outside the Central Nervous System (CNS). Metabolic disease is frequently associated with AAP and significantly impacts the patient's quality of life. However, other peripheral changes of clinical relevance are present during AAP treatment, such as alterations in the immune and endocrine systems as well as the intestinal microbiome. These less studied alterations also have a significant impact in the patient's health status. This manuscript aims to revise the peripheral immunological, endocrine, and intestinal microbiome changes induced by AAP consumption recommended in the clinical guidelines for schizophrenia and other psychiatric disorders.

Quetiapine Abuse Fourteen Years Later: Where Are We Now? A Systematic Review

Background: Quetiapine, an atypical antipsychotic endowed with weak dopamine antagonist, potent 5-HT_2A-blocking, partial 5-HT_1A-agonist, anti-H₁ histamine, adrenolytic, and sigma₁ receptor agonist activities, since an original 2004 report is increasingly misused. Although some of its pharmacodynamics might explain some motives for voluptuary use, most of its actions are directed at setting-off those motives. Hence, it is possible that its popularity in special populations is due to the fact that the unpleasant or unwanted effects of addiction substances are somehow soothed by quetiapine. Currently, quetiapine is tested in substance use disorders, showing some promise, but it is likely to be misused in certain contexts. Objectives: To review the evidence for the use of quetiapine as addiction substance and investigate the characteristics of populations involved in such addiction. Methods: A systematic review of literature on various databases retrieved on September 7, 2018 87 records to comment. Results. We reviewed the evidence for quetiapine's addictive potential in the light of its pharmacodynamics properties and presented two cases of recreational quetiapine use, by a 35-year old male patient with past addictive behavior and by a 50-year-old woman with major depressive disorder and conversion disorder. We found quetiapine to be abused mainly by addict populations and people with law involvement. Conclusions/Importance: There is no reason to include quetiapine among regulated substances, but monitoring of its use in selected populations is warranted. Psychiatrists and physicians working in the penitentiary system should be aware of the addictive potential of quetiapine and adopt measures restricting its use.

Delirium Induced by Quetiapine and the Potential Role of Norquetiapine

Quetiapine in an atypical antipsychotic drug that is frequently used for delirium and behavioral and psychological symptoms in dementia. However, its potential anticholinergic effects, mediated primarily through its metabolite norquetiapine, could present as counterproductive adverse effects in these situations. There is little data published discussing this potential negative impact on quetiapine’s safety and tolerability, especially in the elderly. Here, we present what is, to our knowledge, the first published case report of delirium apparently induced by low-dose quetiapine, in a 95-year-old patient with no prior history of mental illness, and the potential role of its metabolite norquetiapine.

The Discriminative Stimulus Properties of Drugs Used to Treat Depression and Anxiety

Drug discrimination is a powerful tool for evaluating the stimulus effects of psychoactive drugs and for linking these effects to pharmacological mechanisms. This chapter reviews the primary findings from drug discrimination studies of antidepressant and anxiolytic drugs, including novel pharmacological mechanisms. The stimulus properties revealed from these animal studies largely correspond to the receptor affinities of antidepressant and anxiolytic drugs, indicating that subjective effects may correspond to either therapeutic or side effects of these medications. We discuss drug discrimination findings concerning adjunctive medications and novel pharmacologic strategies in antidepressant and anxiolytic research. Future directions for drug discrimination work include an urgent need to explore the subjective effects of medications in animal models, to better understand shifts in stimulus sensitivity during prolonged treatments, and to further characterize stimulus effects in female subjects. We conclude that drug discrimination is an informative preclinical procedure that reveals the interoceptive effects of pharmacological mechanisms as they relate to behaviors that are not captured in other preclinical models.

Thyroid functions in patients with bipolar disorder and the impact of quetiapine monotherapy: a retrospective, naturalistic study

OBJECTIVE

Previous studies have demonstrated a potentially close relationship between mood disorders and thyroid abnormalities. The aims of this study are to investigate: 1) whether significant differences of thyroid profiles exist between manic and depressive episodes in patients with bipolar disorder (BD); 2) the impact of quetiapine monotherapy on thyroid functions in depressed BD patients.

METHODS

In this retrospective naturalistic study, we reviewed patients' information based on an electronic medical system from January 2015 to April 2019. Patients with a discharge diagnosis of BD, a current depressive or manic episode, were screened. All depressed BD patients were treated with quetiapine monotherapy for at least one month. For all patients enrolled, the demographic, clinical data and thyroid functions were recorded. The differences between thyroid profiles including total thyroxine (TT4), total triiodothyronine (TT3), free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) between patients with different episodes were analyzed. In addition, the change of thyroid functions before and after one-month or three-month quetiapine treatment in depressed BD patients was also analyzed.

RESULTS

Totally, 28 patients with a manic episode and 58 patients with a depressive episode were enrolled. No significant differences in thyroid profiles were found in patients with different mood episodes. After one-month quetiapine treatment, serum levels of TT4, FT4 and FT3 were significantly reduced (P<0.05), TSH was increased (P=0.015), while TT3 was not significantly changed (P=0.425). After three-month quetiapine treatment, serum levels of TT4, TT3, FT4 and FT3 were significantly reduced (P<0.05), except TSH (P=0.990).

CONCLUSION

These findings indicate that thyroid functions were not significantly fluctuated between depressive and manic episodes in BD patients. Nonetheless, quetiapine treatment may disturb the thyroid system and needs close monitoring.

Norfluoxetine Prevents Degeneration of Dopamine Neurons by Inhibiting Microglia-Derived Oxidative Stress in an MPTP Mouse Model of Parkinson's Disease

Neuroinflammation is the neuropathological feature of Parkinson's disease (PD) and causes microglial activation and activated microglia-derived oxidative stress in the PD patients and PD animal models, resulting in neurodegeneration. The present study examined whether norfluoxetine (a metabolite of fluoxetine) could regulate neuroinflammation in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine (MPTP) mouse model of PD and rescue dopamine neurons. Analysis by tyrosine hydroxylase (TH) immunohistochemistry demonstrated that norfluoxetine prevents degeneration of nigrostriatal dopamine neurons in vivo in MPTP-lesioned mice compared to vehicle-treated MPTP-lesioned control mice. MAC-1 immunostaining and hydroethidine histochemical staining showed that norfluoxetine neuroprotection is accompanied by inhibiting MPTP-induced microglial activation and activated microglia-derived reactive oxygen species production in vivo, respectively. In the separate experiments, treatment with norfluoxetine inhibited NADPH oxidase activation and nitrate production in LPS-treated cortical microglial cultures in vitro. Collectively, these in vivo and in vitro results suggest that norfluoxetine could be employed as a novel therapeutic agent for treating PD, which is associated with neuroinflammation and microglia-derived oxidative stress.

Is the History Repeated? Can (2R,6R)-Hydroxynorketamine be Another Antidepressant?

Historically, identification of active metabolites has contributed to drug discovery for psychiatric disorders. It has led to the identification of new medications such as desipramine (a metabolite of imipramine) and paliperidone (a metabolite of risperidone). (R,S)-Ketamine, which has been regarded as the greatest breakthrough in depression research, is rapidly and stereoselectively metabolized into a variety of metabolites. Therefore, identification of an active substance after administration of (R,S)-ketamine is a critical issue, not only to delineate the underlying mechanisms but also to pave the way to develop a new antidepressant. Recently, one of the metabolites of (R,S)-ketamine, namely, (2R,6R)-hydroxynorketamine (HNK) was proposed as an active metabolite formed after administration of (R,S)-ketamine, and even as being essential for (R,S)-ketamine to exert its antidepressant effects. However, this is still controversial. Indeed, we demonstrated that the antidepressant effect of (2R,6R)-HNK is not as potent as that of its parent compounds ((R)-ketamine and (R,S)-ketamine), and that (2R,6R)-HNK is not essential for (R)-ketamine to exert its antidepressant effects. From the historical point of view, however, there is potential to discover new medications by further investigations of (2R,6R)-HNK. Therefore, more careful and thorough investigation of (2R,6R)-HNK is needed for the discovery of more efficacious and safer antidepressants.

A History of the Pharmacological Treatment of Bipolar Disorder

In this paper, the authors review the history of the pharmacological treatment of bipolar disorder, from the first nonspecific sedative agents introduced in the 19th and early 20th century, such as solanaceae alkaloids, bromides and barbiturates, to John Cade's experiments with lithium and the beginning of the so-called "Psychopharmacological Revolution" in the 1950s. We also describe the clinical studies and development processes, enabling the therapeutic introduction of pharmacological agents currently available for the treatment of bipolar disorder in its different phases and manifestations. Those drugs include lithium salts, valproic acid, carbamazepine, new antiepileptic drugs, basically lamotrigine and atypical antipsychotic agents (olanzapine, risperidone, quetiapine, ziprasidone, aripiprazole, asenapine, cariprazine and lurasidone). Finally, the socio-sanitary implications derived from the clinical introduction of these drugs are also discussed.

Preparation and in vitro/in vivo evaluation of PLGA microspheres containing norquetiapine for long-acting injection

Background

Norquetiapine (N-desalkyl quetiapine, NQ) is an active metabolite of quetiapine with stable pharmacokinetic and pharmacological properties. However, its short half-life is a drawback for clinical applications, and long-acting formulations are required.

Purpose

The objectives of this study were to prepare improved entrapment efficiency NQ freebase microspheres by the solvent evaporation method with poly(d,l-lactic-co-glycolic acid) (PLGA) as a release modulator and to evaluate their physicochemical and in vitro/in vivo release properties.

Methods

NQ freebase PLGA (1:5 w/w) formulations were prepared by the oil-in-water (o/w) emulsion–solvent evaporation method. A solution of the drug and PLGA in 9:1 v/v dichloromethane:ethanol was mixed with 0.2% polyvinyl alcohol and homogenized at 2,800 rpm. The emulsion was stirred for 3 h to dilute and evaporate the solvent. After that, the resulting product was freeze-dried. Drug-loading capacity was measured by the validated RP-HPLC method. The surface morphology of the microspheres was observed by scanning electron microscopy (SEM), and the physicochemical properties were evaluated by differential scanning calorimetry, powder X-ray diffraction, and Fourier-transform infrared spectroscopy particle size distribution. The in vitro dissolution test was performed using a rotary shaking bath at 37°C, with constant shaking at 50 rpm in sink condition.

Results

The NQ freebase microspheres prepared by o/w emulsion-solvent evaporation showed over 30% efficiency. NQ was confirmed to be amorphous in the microspheres by powder X-ray diffraction and differential scanning calorimetry. Special chemical interaction in the microspheres was not observed by FT-IR. The in vitro dissolution test demonstrated that the prepared microspheres’ release properties were maintained for more than 20 days. The in vivo test also confirmed that the particles’ long acting properties were maintained. Therefore, good in vitro–in vivo correlation was established.

Conclusion

In this study, NQ freebase-PLGA microspheres showed potential for the treatment of schizophrenia for long-periods.

Characterizing the Effects of Quetiapine in Military Post-Traumatic Stress Disorder

OBJECTIVES

A previous randomized placebo-controlled trial in military veterans posttraumatic stress disorder (PTSD) found that quetiapine improved global PTSD symptoms severity, depression and anxiety as well as the re-experiencing and hypearousal clusters. However, it is not known if individual symptoms had a preferential response to this medication. The goal of this study was to analyze the individual symptom response in this group of patients.

METHODS

Data from a previous trial was re-analyzed. Each of the of the scale items was analyzed individually using Repeated Measures Analysis of Variance.

RESULTS

Compared to placebo, there was a significant decline in the Clinician-Administered PTSD Scale intrusive memories and insomnia questions. In the Davidson Trauma Scale, greater improvements were observed on irritability, difficulty concentrating, hyperstartle and a trend was observed on avoiding thoughts or feelings about the event. Greater improvements compared with placebo were noted on the Hamilton Depression (HAM-D) middle and late insomnia items. On the Hamilton Anxiety scale (HAM-A), the insomnia item was significantly improved.

CONCLUSIONS

Quetiapine demonstrated greater effect than placebo on several symptoms. The strongest response was seen on insomnia, which the highest significance level on the CAPS. The insomnia items of both the HAM-D and HAM-A also demonstrated improvement with quetiapine. These finding indicate quetiapine improved sleep measure. Insomnia can be a difficult problem to treat in PTSD patients, therefore quetiapine should be considered in difficult cases.

Divergent effects of acute and repeated quetiapine treatment on dopamine neuron activity in normal vs. chronic mild stress induced hypodopaminergic states

Clinical evidence supports the use of second-generation dopamine D2 receptor antagonists (D2RAs) as adjunctive therapy or in some cases monotherapy in patients with depression. However, the mechanism for the clinical antidepressant effect of D2RAs remains unclear. Specifically, given accumulating evidence for decreased ventral tegmental area (VTA) dopamine system function in depression, an antidepressant effect of a medication that is expected to further reduce dopamine system activity seems paradoxical. In the present paper we used electrophysiological single unit recordings of identified VTA dopamine neurons to characterize the impact of acute and repeated administration of the D2RA quetiapine at antidepressant doses in non-stressed rats and those exposed to the chronic mild stress (CMS) rodent depression model, the latter modeling the hypodopaminergic state observed in patients with depression. We found that acute quetiapine increased dopamine neuron population activity in non-stressed rats, but not in CMS-exposed rats. Conversely, repeated quetiapine increased VTA dopamine neuron population activity to normal levels in CMS-exposed rats, but had no persisting effects in non-stressed rats. These data suggest that D2RAs may exert their antidepressant actions via differential effects on the dopamine system in a normal vs. hypoactive state. This explanation is supported by prior studies showing that D2RAs differentially impact the dopamine system in animal models of schizophrenia and normal rats; the present results extend this phenomenon to an animal model of depression. These data highlight the importance of studying medications in the context of animal models of psychiatric disorders as well as normal conditions.

Effects of norquetiapine, the active metabolite of quetiapine, on cloned hERG potassium channels

Quetiapine is an atypical antipsychotic drug that is widely used for the treatment of schizophrenia. It is mainly metabolized by a cytochrome P450 system in the liver. Norquetiapine is a major active metabolite in humans with a pharmacological profile that differs distinctly from that of quetiapine. We used the whole-cell patch-clamp technique to investigate the effects of norquetiapine on hERG channels that are stably expressed in HEK cells. Quetiapine and norquetiapine inhibited the hERG tail currents at -50mV in a concentration-dependent manner with IC₅₀ values of 8.3 and 10.8μM, respectively, which suggested equal potency. The block of hERG currents by norquetiapine was voltage-dependent with a steep increase over a range of voltages for channel activation. However, at more depolarized potentials where the channels were fully activated, the block by norquetiapine was voltage-independent. The steady-state inactivation curve of the hERG currents was shifted to the hyperpolarizing direction in the presence of norquetiapine. Norquetiapine did not produce a use-dependent block. A fast application of norquetiapine inhibited the hERG current elicited by a 5s depolarizing pulse to +60mV, which fully inactivated the hERG currents, suggesting an inactivated-state block. During a repolarizing pulse wherein the hERG current was slowly deactivated, albeit remaining in an open state, a fast application of norquetiapine rapidly and reversibly inhibited the open state of the hERG current. Our results indicated that quetiapine and norquetiapine had equal potency in inhibiting hERG tail currents. Norquetiapine inhibited the hERG current by preferentially interacting with the open and/or inactivated states of the channels.

Why Prodrugs and Propesticides Succeed

What are the advantages of bioactivation in optimizing drugs and pesticides? Why are there so many prodrugs and propesticides? These questions are examined here by considering compounds selected on the basis of economic value or market success in 2015. The 100 major drugs and 90 major pesticides are divided into ones acting directly and those definitely or possibly requiring bioactivation. Established or candidate prodrugs accounted for 19% of the total drug sales, with corresponding values of 20, 37, and 17% for proinsecticides, proherbicides, and profungicides. The 19 prodrugs acting in humans generally had better pharmacodynamic/pharmacokinetic properties for target enzyme, receptor, tissue, or organ specificity due to their physical properties (lipophilicity and stabilization). Bioactivation usually involved hydrolases or cytochrome P450 oxidation or reduction. Prodrugs considered are neuroactive aripiprazole, eletriptan, desvenlafaxin, lisdexamfetamine, quetiapine, and fesoterodine; cholesterol-lowering atorvastatin, ezetimibe, and fenofibrate; various prodrugs activated by esterases or sulfatases, ciclesonide, oseltamivir, dabigatran; omega-3 fatty acid ethyl esters and esterone sulfate; and five others with various targets (sofosbuvir, fingolimod, clopidogrel, dapsone, and sildenafil). The proinsecticides are the neuroactive chlorpyrifos, thiamethoxam, and indoxacarb, two spiro enol ester inhibitors of acetyl CoA carboxylase (ACCase), and the bacterial protein delta-endotoxin. The proherbicides considered are five ACCase inhibitors including pinoxaden and clethodim, three protox inhibitors (saflufenacil, flumioxazin, and canfentrazone-ethyl), and three with various targets (fluroxypyr, isoxaflutole, and clomazone). The profungicides are prothioconazole, mancozeb, thiophanate-methyl, dazomet, and fosetyl-aluminum. The prodrug and propesticide concept is broadly applicable and has created some of the most selective pharmaceutical and pest control agents, illustrated here by major compounds that partially overcome pharmacokinetic limitations of potency and selectivity in the corresponding direct-acting compounds. The challenges of molecular design extend beyond the target site fit to the bioactivatable precursor and the fascinating chemistry and biology matched against the complexity of life processes.

Comparative Physicochemical and Pharmacokinetic Properties of Quetiapine and Its Active Metabolite Norquetiapine

Quetiapine (QTP) is an atypical antipsychotic drug commonly used to treat several psychiatric disorders and is metabolized into the active metabolite norquetiapine (NQTP). This study was designed to evaluate and compare the physicochemical properties, metabolic stability, brain distribution, and pharmacokinetics of QTP and NQTP. Compared to QTP, NQTP had a higher pK_a, solubility, and rat liver microsomal stability, optimal log D and similar log P values. For pharmacokinetic evaluation, QTP and NQTP were administered orally and intravenously to rats at various doses. The plasma QTP and NQTP concentrations in rats were determined by a fully-validated liquid-chromatography tandem mass spectrometry (LC-MS/MS). Over the investigated dosing range, both QTP and NQTP showed linear pharmacokinetics. Following oral administration of the same dose, the area under the concentration-time curve (AUC_0-∞) and maximum serum concentration (C_max) were larger after NQTP administration compared to QTP administration. In addition, NQTP had a greater absolute oral bioavailability compared to QTP (15.6% vs. 0.63%, respectively). The brain-to-plasma concentration ratio was greater after NQTP administration compared to the QTP and NQTP ratios after QTP administration. NQTP administration results in increased systemic exposure and brain distribution compared to QTP administration. Future studies are needed to evaluate the pharmacologic and toxicologic effects of increased NQTP exposures.

Simultaneous quantitation of quetiapine and its active metabolite norquetiapine in rat plasma and brain tissue by high performance liquid chromatography/electrospray ionization tandem mass spectrometry (LC-MS/MS)

A sensitive method to simultaneously quantitate quetiapine and norquetiapine in rat plasma and brain tissue was developed using a one-step liquid-liquid extraction for sample preparation and LC-MS/MS for detection. The method provided a linear range of 1.0-500.0ng/mL for each analyte in plasma and 3.0-1500.0ng/g in brain tissue. The method was validated with precision within 15% relative standard deviation (RSD), accuracy within 15% relative error (RE), matrix effects within 10% and a consistent recovery. This method has been successfully applied in a preclinical study of quetiapine and norquetiapine to simultaneously determine their concentrations in rat plasma and brain tissue.

[Abuse Liability of Quetiapine (Xeroquel®)]

OBJECTIVE

In recent years, there have been several reports in the literature concerning the misuse and abuse of quetiapine. The aim of this study was to review the data reported to the French Network of the Addictovigilance Centers as well as the published data.

METHODS

Epidemiological data from the studies of French network addictovigilance centers (spontaneous notifications, suspicious presciptions suggesting possible abuse [ ordonnances suspectes indicateur d'abus possibles, OSIAP], observatory of illegal psychotropic substances or delivered substances diverted from their medicinal use survey [observation des produits psychotropes illicites ou détournées de leur utilisation médicamenteuse, OPPIDUM], deaths related to medication and substance abuse survey [décès en relation avec l'abus de médicaments et de substances, DRAMES]) were analyzed between 2011 and 2014. All cases of abuse and dependence with quetiapine in PubMed were reviewed using the MeSH terms "quetiapine," "substances abuse," and "dependence", until October 2014.

RESULTS

The analysis of the literature has identified 21 cases of abuse related to quetiapine, mainly in men (85.7%), with a history of substance abuse (76%). The main route of administration was oral but other routes were also reported (intravenous, intranasal). The main reason for abuse was sedation and anxiolytic. Other characteristics of quetiapine abuse include amplification or even simulation of psychotic symptoms to obtain quetiapine, an increased dose and the existence of street names. The French addictovigilance network reported few cases of abuse with quetiapine.

DISCUSSION-CONCLUSION

The pharmacological mechanism of abuse of quetiapine is not fully understood. However, several arguments are in favor of the abuse liability of quetiapine. Despite the recent availability of quetiapine in France, there have been some isolated signals of abuse. Therefore, it seems important to inform prescribers on the risk of misuse of quetiapine and also of some other antipsychotics.

The effect of the antipsychotic drug quetiapine and its metabolite norquetiapine on acute inflammation, memory and anhedonia

The atypical antipsychotic drug, quetiapine, has recently been suggested to not only show efficacy in schizophrenia, bipolar, major depressive and general anxiety disorders, but to also have a possible anti-inflammatory effect, which could be important in the treatment of the inflammatory aspects of psychiatric diseases. Male C57BL/6 mice were given either quetiapine (i.p. 10mg/kg), its main active metabolite norquetiapine (i.p. 10mg/kg), or saline as a vehicle control, once a day for 14days. On the 14th day, this dose was followed by a single dose of either LPS (i.p. 1mg/kg) or saline. 24h post LPS short-term recognition memory and anhedonia behaviour were measured using the Y-maze and saccharin preference test respectively. Immediately following behavioural testing, mice were culled before serum, prefrontal cortex and hippocampal analysis of cytokine levels was conducted. It was found that LPS challenge led to increased serum and brain cytokine levels as well as anhedonia, with no significant effect on recognition memory. Quetiapine and norquetiapine both increased levels of the anti-inflammatory cytokine IL-10 and decreased levels of the pro-inflammatory cytokine IFN-γ in serum 4h post LPS. Within the brain, a similar pattern was seen in gene expression in the hippocampus at 4h for Il-10 and Ifn-γ, however norquetiapine led to an increase in Il-1β expression in the PFC at 4h, while both drugs attenuated the increased Il-10 in different regions of the brain at 24h. These effects in the serum and brain, however, had no effect on the observed LPS induced changes in behaviour. Both quetiapine and its metabolite norquetiapine appear to have a partial anti-inflammatory effect on IL-10 and IFN-γ following acute LPS challenge in serum and brain, however these effects did not translate into behavioural changes.

Pharmacotherapy of bipolar disorder with quetiapine: a recent literature review and an update

Bipolar disorder is a chronic, recurrent condition with the usual onset during adolescence or early adulthood. In the Diagnostic and Statistical Manual of Mental Disorders 5th edition, it is conceptualized as a spectrum disorder usually associated with such comorbidities as anxiety disorders and substance use disorders. It is a relatively prevalent condition often complicated by mixed episodes, rapid cycling, subsyndromal symptoms, and treatment refractoriness. In spite of carrying substantial morbidity and mortality, effective treatments are few and far between and conventional mood stabilizers are often unsuccessful in controlling the various manifestations of the disorder. In this scenario, second generation antipsychotics are emerging as treatments with valid efficacy in all phases of bipolar disorder. Quetiapine is a versatile atypical antipsychotic which was first approved for the treatment of schizophrenia, but latter on the basis of controlled studies earned United States Food and Drug Administration’s approval for acute as well as maintenance treatment of this difficult to treat condition. In this review, recently published studies in the last 10 years were examined to update the knowledge about the efficacy and safety of quetiapine in the treatment of bipolar disorder. The medication’s clinical pharmacology was first considered followed by a literature review summarizing its uses in bipolar disorder. The conclusion was that quetiapine was efficacious in manic, mixed and depressive episodes and as a maintenance agent with a good tolerability profile.

Role of quetiapine beyond its clinical efficacy in bipolar disorder: From neuroprotection to the treatment of psychiatric disorders (Review)

The aim of the present review was to discuss the following aspects of treatment with quetiapine in psychiatric disorders: i) Neurocognition and functional recovery in bipolar disorder (BD); ii) neuroprotective profile in different models; and iii) potential off-label indications. A PubMed search was conducted of articles published in English between 2000 and 2012 on quetiapine, cross-referenced with the terms ‘anxiety’, ‘attention deficit disorder’, ‘borderline personality disorder’, ‘dementia’, ‘insomnia’, ‘major depressive disorder’ (MDD), ‘obsessive-compulsive disorder’, ‘post-traumatic stress disorder’, ‘remission’, ‘cognition’, ‘neurobiology’, ‘neuroprotection’, ‘efficacy’ and ‘effectiveness’. Articles were selected from meta-analyses, randomized clinical trials and open trials, and the results were summarized. Quetiapine, when studied in off-label conditions, has shown efficacy as a monotherapy in MDD and general anxiety disorder. Quetiapine also appears to exhibit a small beneficial effect in dementia. The review of other conditions was affected by methodological limitations that precluded any definitive conclusions on the efficacy or safety of quetiapine. Overall, the present review shows evidence supporting a potential role for quetiapine in improving cognition, functional recovery and negative symptoms in a cost-effective manner in BD. These benefits of quetiapine are potentially associated with its well-described neuroprotective effects; however, further studies are clearly warranted.