Haloperidol, Olanzapine, and Risperidone Induce Morphological Changes in an In Vitro Model of Human Hippocampal Neurogenesis.

BACKGROUND: Induced pluripotent stem cell (iPSC) based neuronal differentiation is valuable for studying neuropsychiatric disorders and pharmacological mechanisms at the cellular level. We aimed to examine the effects of typical and atypical antipsychotics on human iPSC-derived neural progenitor cells (NPCs). METHODS: Proliferation and neurite outgrowth were measured by live cell imaging, and gene expression levels related to neuronal identity were analyzed by RT-QPCR and immunocytochemistry during differentiation into hippocampal dentate gyrus granule cells following treatment of low- and high-dose antipsychotics (haloperidol, olanzapine, and risperidone). RESULTS: Antipsychotics did not modify the growth properties of NPCs after 3 days of treatment. However, the characteristics of neurite outgrowth changed significantly in response to haloperidol and olanzapine. After three weeks of differentiation, mRNA expression levels of the selected neuronal markers increased (except for MAP2), while antipsychotics caused only subtle changes. Additionally, we found no changes in MAP2 or GFAP protein expression levels as a result of antipsychotic treatment. CONCLUSIONS: Altogether, antipsychotic medications promoted neurogenesis in vitro by influencing neurite outgrowth rather than changing cell survival or gene expression. This study provides insights into the effects of antipsychotics on neuronal differentiation and highlights the importance of considering neurite outgrowth as a potential target of action.

Evaluation of the pharmacodynamic interaction effect of augmentation agents with clozapine in patients with treatment-resistant schizophrenia: A simulation study of clinical data.

INTRODUCTION: The aim of the study was to evaluate interaction effect of various augmentation strategies with clozapine in patients with Treatment-resistant schizophrenia. METHODS: Data was extracted for change in positive and negative syndrome scale (PANSS) or brief psychiatric rating scale (BPRS) scores for monotherapy with various antipsychotic agents alone and their combination with clozapine. Individual patient data was generated using simulation of data (factorial trial framework) from published clinical trials for sample sizes from eight to 400 to evaluate interaction effect through linear modeling. Dose equivalents were calculated, and best fit models were determined for simulated data. RESULTS: The polynomial model was found to be the best fit for the simulated data to determine interaction effect of combination. The clozapine augmentation with risperidone and ziprasidone was found to be antagonistic, whereas it was additive for haloperidol, aripiprazole, and quetiapine. A synergistic effect was observed for ECT combined with clozapine (Interaction effect: -7.62; p <0.001). A sample size of 250-300 may be sufficient to demonstrate a clinically significant interaction in future trials. CONCLUSION: Clozapine may be augmented with electroconvulsive therapy, leading to the enhancement of antipsychotic effect. Though some antipsychotics like aripiprazole demonstrate additive effects, they may also add to the adverse effects.

Into a Deeper Understanding of CYP2D6's Role in Risperidone Monotherapy and the Potential Side Effects in Schizophrenia Spectrum Disorders.

Schizophrenia spectrum disorders (SSD) are a group of diseases characterized by one or more abnormal features in perception, thought processing and behavior. Patients suffering from SSD are at risk of developing life-threatening complications. Pharmacogenetic studies have shown promising results on personalized treatment of psychosis. In the current study, 103 patients diagnosed with SSD treated with risperidone as antipsychotic monotherapy were enrolled. Socio-demographics and clinical data were recorded, and laboratory tests and genotyping standard procedure for cytochrome P450 (CYP) 2D6*4 were performed. Patients were evaluated by the Positive and Negative Syndrome Scale (PANSS) on admission and at discharge. Based on the reduction in the PANSS total score, subjects were divided into non-responders, partial responders and full responders. Only 11 subjects had a full response to risperidone (10.67%), 53 subjects (51.45%) had a partial response, and 39 participants (37.86%) were non-responders. Patients at first episode psychosis showed significantly higher levels of blood glucose and prolactin levels, while chronic patients showed significantly higher LDL levels. Adverse drug reactions (ADR) such as tremor and stiffness significantly correlated with genetic phenotypes (p = 0.0145). While CYP2D6 showed no impact on treatment response, ADR were significantly more frequent among poor and intermediate metabolizers.

Association between voriconazole-induced visual hallucination and dopamine in an analysis of the food and drug administration (FDA) adverse event reporting system database.

Voriconazole is a second-generation azole used to treat serious fungal infections. Visual hallucinations constitute a representative adverse event caused by voriconazole. However, its mechanism of action remains unclear. In patients with schizophrenia or Parkinson's disease, the frequency of visual hallucinations is associated with brain dopamine levels. This study investigated the frequency of visual hallucinations in patients treated with voriconazole alone or in combination with dopaminergic medicines or dopamine antagonists, using data collected from the Food and Drug Administration Adverse event Reporting System (FAERS). The frequency of visual hallucinations with voriconazole alone and in combination with a dopaminergic medicine (levodopa) or dopamine antagonists (risperidone and chlorpromazine) was compared using data from the FAERS between 2004 and 2023, using the reporting odds ratio (ROR) with relevant 95% confidence intervals (CI). The reference group comprised patients who had been administered voriconazole without dopaminergic medication or dopamine antagonists. Of the patients, 22,839, 90,810, 109,757, 6,435, 20, 83, and 26, respectively were treated with voriconazole, levodopa, risperidone, chlorpromazine, voriconazole plus levodopa, voriconazole plus risperidone, and voriconazole plus chlorpromazine. The occurrence of visual hallucinations increased when used in combination with levodopa (ROR = 12.302, 95% CI = 3.587-42.183). No increase in incidence was associated with the concomitant use of dopamine antagonists (risperidone, ROR = 1.721, 95% CI = 0.421-7.030; chlorpromazine, ROR = none, 95% CI = none). Dopaminergic medicine may increase the risk of visual hallucinations in patients treated with voriconazole. Whether voriconazole positively modulates dopamine production warrants further investigation using a translational research approach.

Mortality risk and mood stabilizers in bipolar disorder: a propensity-score-weighted population-based cohort study in 2002-2018.

AIMS: Accumulating studies have assessed mortality risk associated with mood-stabilizers, the mainstay treatment for bipolar disorder (BD). However, existing data were mostly restricted to suicide risk, focused on lithium and valproate and rarely adequately adjusted for potential confounders. This study aimed to assess comparative mortality risk with all, natural and unnatural causes between lithium, valproate and three frequently prescribed second-generation antipsychotics (SGA), with adjustment for important confounders. METHODS: This population-based cohort study identified 8137 patients with first-diagnosed BD, who had exposed to lithium (n = 1028), valproate (n = 3580), olanzapine (n = 797), quetiapine (n = 1975) or risperidone (n = 757) between 2002 and 2018. Data were retrieved from territory-wide medical-record database of public healthcare services in Hong Kong. Propensity-score (PS)-weighting method was applied to optimize control for potential confounders including pre-existing chronic physical diseases, substance/alcohol use disorders and other psychotropic medications. PS-weighted Cox proportional-hazards regression was conducted to assess risk of all-, natural- and unnatural-cause mortality related to each mood-stabilizer, compared to lithium. Three sets of sensitivity analyses were conducted by restricting to patients with (i) length of cumulative exposure to specified mood-stabilizer ≥90 days and its medication possession ratio (MPR) ≥90%, (ii) MPR of specified mood-stabilizer ≥80% and MPR of other studied mood-stabilizers <20% and (iii) monotherapy. RESULTS: Incidence rates of all-cause mortality per 1000 person-years were 5.9 (95% confidence interval [CI]: 4.5-7.6), 8.4 (7.4-9.5), 11.1 (8.3-14.9), 7.4 (6.0-9.2) and 12.0 (9.3-15.6) for lithium-, valproate-, olanzapine-, quetiapine- and risperidone-treated groups, respectively. BD patients treated with olanzapine (PS-weighted hazard ratio = 2.07 [95% CI: 1.33-3.22]) and risperidone (1.66 [1.08-2.55]) had significantly higher all-cause mortality rate than lithium-treated group. Olanzapine was associated with increased risk of natural-cause mortality (3.04 [1.54-6.00]) and risperidone was related to elevated risk of unnatural-cause mortality (3.33 [1.62-6.86]), relative to lithium. The association between olanzapine and increased natural-cause mortality rate was consistently affirmed in sensitivity analyses. Relationship between risperidone and elevated unnatural-cause mortality became non-significant in sensitivity analyses restricted to low MPR in other mood-stabilizers and monotherapy. Valproate- and lithium-treated groups did not show significant differences in all-, natural- or unnatural-cause mortality risk. CONCLUSION: Our data showed that olanzapine and risperidone were associated with higher mortality risk than lithium, and further supported the clinical guidelines recommending lithium as the first-line mood-stabilizer for BD. Future research is required to further clarify comparative mortality risk associated with individual SGA agents to facilitate risk-benefit evaluation of alternative mood-stabilizers to minimize avoidable premature mortality in BD.

Atypical Antipsychotic Prescribing in Australian Children and Adolescents: A Survey of Medical Practitioners.

OBJECTIVE: Prescriptions for atypical antipsychotics in children and adolescents are increasing globally. However, a precise understanding of the clinical variables and evidence that prescribers consider before using these agents is lacking. While empirical literature on the long-term safety and efficacy of these medications is available, the literature concerning their use in these younger age groups is relatively sparse. In this study, we examined the current prescribing patterns of medical professionals employed by a public health service in Australia. METHODS: A survey examining their current practice when prescribing atypical antipsychotics to children and adolescents was completed by 103 physicians. Questions were asked about commonly prescribed atypical antipsychotics, indications, dose ranges, target symptoms, duration of treatment, and the evidence base(s) used when making treatment decisions. RESULTS: Physicians prescribed atypical antipsychotics for a wide range of indications in this age group, with the most common agents being risperidone, quetiapine, and olanzapine. Adverse effects were reported as the main reason for treatment discontinuation. More than half of the respondents indicated that the most common source of guidance/evidence they referred to when initiating prescriptions were peers or expert opinion. CONCLUSIONS: Children and adolescents were prescribed a number of atypical antipsychotics for a variety of indications, with variable perceived confidence and a relatively heavy reliance on "own or peer experience" as opposed to good quality evidence. Challenges exist for both prescribers and policymakers, and further "head-to-head" studies are needed in this age group to ensure that a balance is maintained between therapeutic benefit and safety.

Antipsychotic drug-induced behavioral abnormalities in common carp: The potential involvement of the gut microbiota-brain axis.

The effects of antipsychotic drugs on aquatic organisms have received widespread attention owing to their widespread use and continued release in aquatic environments. The toxicological effects of antipsychotics on aquatic organisms, particularly fish, are unexplored, and the underlying mechanisms remain unelucidated. This study aimed to use common carp to explore the effects of antipsychotics (olanzapine [OLA] and risperidone [RIS]) on behavior and the potential mechanisms driving these effects. The fish were exposed to OLA (0.1 and 10 µg/L) and RIS (0.03 and 3 µg/L) for 60 days. Behavioral tests and neurological indicators showed that exposure to antipsychotics could cause behavioral abnormalities and neurotoxicity in common carp. Further, 16 S rRNA sequencing revealed gut microbiota alteration and decreased relative abundance of some strains related to SCFA production after OLA and RIS exposure. Subsequently, a pseudo-sterile common carp model was successfully constructed, and transplantation of the gut microbiota from antipsychotic-exposed fish caused behavioral abnormalities and neurotoxicity in pseudo-sterile fish. Further, SCFA supplementation demonstrated that SCFAs ameliorated the behavioral abnormalities and neurological damage caused by antipsychotic exposure. To our knowledge, the present study is the first to investigate the effects of antipsychotics on various complex behaviors (swimming performance and social behavior) in common carp, highlighting the potential health risks associated with antipsychotic drug-induced neurotoxicity in fish. Although these results do not fully elucidate the mechanisms underlying the effects of antipsychotic drugs on fish behavior, they serve as a valuable initial investigation and form the basis for future research.

Hemichorea-hemiballismus due to diabetic striatopathy a serious complication of uncontrolled diabetes.

We report the case of a man in his mid-80s with diabetes mellitus who presented to the emergency department with a 1-day history of right-sided choreiform movements and falls. Laboratory tests revealed blood glucose of 597 mg/dL. Non-contrast CT imaging of his head demonstrated a faint hyperdensity involving the left lentiform nucleus and brain MRI showed a hyperintensity in the left basal ganglia on T1-weighted images. These lesions are typical of diabetic striatopathy. Symptoms of hemichorea/hemiballismus did not resolve with glycaemic control and several pharmacological agents were tried with eventual improvement with risperidone. He was discharged to a rehabilitation facility and had mild persistent arm chorea at 6-month follow-up.

Influence of CYP2C19 and CYP2D6 on side effects of aripiprazole and risperidone: A systematic review.

Variability in hepatic cytochrome P450 (CYP) enzymes such as 2C19 and 2D6 may influence side-effect and efficacy outcomes for antipsychotics. Aripiprazole and risperidone are two commonly prescribed antipsychotics, metabolized primarily through CYP2D6. Here, we aimed to provide an overview of the effect of CYP2C19 and CYP2D6 on side-effects of aripiprazole and risperidone, and expand on existing literature by critically examining methodological issues associated with pharmacogenetic studies. A PRISMA compliant search of six electronic databases (Pubmed, PsychInfo, Embase, Central, Web of Science, and Google Scholar) identified pharmacogenetic studies on aripiprazole and risperidone. 2007 publications were first identified, of which 34 were included. Quality of literature was estimated using Newcastle-Ottowa Quality Assessment Scale (NOS) and revised Cochrane Risk of Bias tool. The average NOS score was 5.8 (range: 3-8) for risperidone literature and 5 for aripiprazole (range: 4-6). All RCTs on aripiprazole were rated as high risk of bias, and four out of six for risperidone literature. Study populations ranged from healthy volunteers to inpatient individuals in psychiatric units and included adult and pediatric samples. All n = 34 studies examined CYP2D6. Only one study genotyped for CYP2C19 and found a positive association with neurological side-effects of risperidone. Most studies did not report any relationship between CYP2D6 and any side-effect outcome. Heterogeneity between and within studies limited the ability to synthesize data and draw definitive conclusions. Studies lacked statistical power due to small sample size, selective genotyping methods, and study design. Large-scale randomized trials with multiple measurements, providing robust evidence on this topic, are suggested.

Neuroleptic Malignant Syndrome Concurrent with COVID-19 Infection: A Case Report. / COVID-19 Hastasinda Nöroleptik Malin Sendrom: Bir Olgu Sunumu.

Neuroleptic malignant syndrome (NMS), which most often occurs after the use of antipsychotics, is a rare but life-threatening condition. In this article, a 56-year-old male patient with a diagnosis of bipolar affective disorder (BPD) who developed NMS after a COVID-19 infection will be presented. The patient had been brought to the emergency room with high fever, fatigue, and slowness of movements that had been going on for two days. The examination revealed tachycardia, tachypnea, lethargy and rigidity. Upon further investigation the COVID-19 test came out positive and the serum levels of creatine kinase were considerably high. He was admitted to the psychiatric ward with diagnoses of COVID-19 infection and NMS. COVID-19 infection might have been a risk factor for NMS in this patient. Especially in patients who are taking antipsychotic drugs, if COVID-19 is present, the risk of NMS should be taken into consideration. Keyword: COVID-19, Neuroleptic Malignant Syndrome, Risperidone, Antipsikotik, Enfeksiyon.

Efficacy of probiotic supplements in improving the symptoms of psychosis, anxiety, insomnia, and anorexia due to amphetamine and methamphetamine use: a randomized clinical trial.

RATIONALE: Changes in the density and diversity of gut microbiota in chronic use of methamphetamine have been mentioned as contributors to psychotic and anxiety symptoms, sleep problems, and loss of appetite. OBJECTIVE: In this placebo-controlled clinical trial, we investigated the effect of the probiotic Lactobacillus Acidophilus in improving psychiatric symptoms among hospitalized patients with chronic methamphetamine use along with psychotic symptoms. METHODS: 60 inpatients with a history of more than 3 years of methamphetamine use, were randomly assigned to one of two groups receiving either a probiotic capsule or placebo along with risperidone for 8 weeks based on a simple randomization method. In weeks 0, 4, and 8, patients were evaluated using the Brief Psychiatric Rating Scale (BPRS), Beck Anxiety Inventory (BAI), Pittsburgh Sleep Quality Index (PSQI), Simple Appetite Nutritional Questionnaire (SANQ), and Body Mass Index (BMI). RESULTS: Compared to the control group, patients receiving probiotics had better sleep quality, greater appetite, and higher body mass index (there were significant interaction effects of group and time at Week 8 in these variables (t = -3.32, B = -1.83, p = .001, d = 0.89), (t = 10.50, B = 2.65, p <.001, d = 1.25) and (t = 3.40, B = 0.76, p <.001, d = 0.30), respectively. In terms of the improvement of psychotic and anxiety symptoms, there was no statistically significant difference between the two groups. CONCLUSIONS: The use of probiotics was associated with improved sleep quality, increased appetite, and increased body mass index in patients with chronic methamphetamine use. Conducting more definitive clinical trials with larger sample sizes and longer-term follow-up of cases is recommended.

Long-acting second-generation injectable antipsychotics for the maintenance treatment of bipolar disorder: a narrative review.

INTRODUCTION: Non-adherence to medication significantly affects bipolar disorder outcomes. Long-Acting Injectable antipsychotics show promise by ensuring adherence and averting relapses. AREAS COVERED: This narrative review sought to evaluate the efficacy of second-generation injectable antipsychotics in bipolar disorder through searches in Embase, MEDLINE, and PsycInfo for randomized controlled trials and mirror-image studies.Risperidone and aripiprazole Long-Acting Injectables demonstrated effectiveness in preventing mood recurrences compared to placebos in adults with bipolar disorder. They showed superiority in preventing mania/hypomania relapses over placebos but did not appear to significantly outperform active oral controls. Notably, active controls seem to be more effective in preventing depression relapses than Long-Acting Injectables. Mirror-Image studies point toward the reduction of hospitalization rates following LAI initiation. EXPERT OPINION: The available evidence points thus toward the efficacy of LAIs, especially in managing manic episodes and reducing hospitalizations, The current evidence does not however immediately support prioritizing LAIs over oral medications in bipolar disorder treatment. More high-quality studies, especially comparing LAIs directly with active controls, are crucial to gain a comprehensive understanding of their efficacy. These findings highlight the need for further research to guide clinicians in optimizing treatment strategies for bipolar disorder.

Pregabalin Adjuventia Helped Risperidone-Induced Extrapyramidal Syndrome and Augmented Antipsychotic Response in an Adolescent with Schizophrenia.

Here, authors report on an interesting case of early-onset of schizophrenia where adjunctive pregabalin alleviated risperidone-induced pseudoparkinsonism, helped with insomnia and agitation and boosted antipsychotic response with great tolerability. We wager that gabapentenoids can be a viable option in the niche of psychopharmacotherapy of schizophrenia in CAP population.

Genotoxic and genoprotective effects of some antipsychotic drugs, methylphenidate and atomoxetine on human lymphocytes and HepG2 cells.

OBJECTIVE: Aripiprazole, risperidone, atomoxetine, and methylphenidate are drugs commonly prescribed for many psychiatric conditions and can be used alone or in combination in children and adolescents. This study aimed to investigate comparatively the possible genotoxic effects or genoprotective potentials of these drugs on human lymphocytes and HepG2 cells. MATERIALS AND METHODS: Cytotoxicity analysis was performed with the cell viability test on human lymphocytes and HepG2 cells, and half-maximal inhibitory concentration (IC50) values of the drugs were determined, and three different doses (» IC50, ½ IC50, and IC50) were applied for genetic analysis. For the determined doses, cells with and without DNA damage were examined by comet analysis. RESULTS: In lymphocytes, aripiprazole and risperidone increased DNA damage at moderate and maximum doses, whereas atomoxetine increased DNA damage only at the maximum dose. In HepG2 cells, risperidone reduced DNA damage at all doses, while atomoxetine increased DNA damage at all doses. On the other hand, in the DNA-damaged cells induced by hydrogen peroxide (H2O2), DNA damage decreased at all concentrations of all drugs in both lymphocytes and HepG2 cells. CONCLUSIONS: As a result, the genotoxicity of the drugs was found to be dose-dependent, and all drugs showed a genoprotective effect on DNA-damaged cells.

Risperidone-Induced Leukoneutropenia: Evidence from a Positive Rechallenge and Review of the Literature.

Antipsychotics can cause hematologic disorders, and they can have life-threatening consequences. Risperidone, less commonly associated with hematologic adverse effects, is an atypical antipsychotic medication used to treat conditions such as schizophrenia, bipolar disorder and irritability associated with autism. While risperidone primarily affects the central nervous system, it can have some hematologic adverse effects, although these are relatively rare. It is crucial to note that these side effects are not common, and most people taking risperidone do not experience hematologic disorders. The reporting of such disorders may be more frequent with clozapine compared to other atypical antipsychotics because clozapine treatment necessitates regular hematological monitoring 1.

Gynura procumbens and selected metabolites: Amelioration of depressive-like behaviors in mice and risperidone-induced hyperprolactinemia in rats.

Gynura procumbens (Lour.) Merr., utilized in traditional Chinese medicine, is known for its liver-protective, liver-soothing, and depression-alleviating properties. This research examines the antidepressant and anti-hyperprolactinemia potentials of an ethanol extract from G. procumbens stems (EEGS) and specific metabolites. To model depression and hyperprolactinemia, chronic unpredictable mild stress (CUMS) was induced in mice and risperidone was administered to rats, respectively. Treatments involved administering low (5 mg/kg), medium (25 mg/kg), and high (125 mg/kg) doses of EEGS and certain metabolites to both models. Behavioral assessments were conducted in the CUMS-induced mice, while the CA3 neuronal damage in mice and histopathological alterations in rat mammary glands were evaluated using Nissl and Hematoxylin & Eosin staining techniques, respectively. EEGS decreased immobility times in the forced swimming and tail suspension tests in mice, enhancing their exploration of the central zone. It elevated the serum levels of 5-hydroxytryptamine, norepinephrine, estradiol, luteinizing hormone (LH), and testosterone in mice. Moreover, EEGS restored the neuronal cell arrangement in the CA3 area, reduced interleukin-1beta mRNA production, and increased the expression of interleukin-10 and beta-catenin mRNA. In the context of risperidone-induced hyperprolactinemia, EEGS lowered blood prolactin levels, reduced the dimensions of rat nipples, and enhanced LH, progesterone, and dopamine levels, alongside mitigating mammary hyperplasia. Among the EEGS selected metabolites, the combined effect of chlorogenic acid and trans-p-coumaric acid was found to be more effective than the action of each compound in isolation. Collectively, the findings indicate that EEGS and its selected metabolites offer promising antidepressant benefits while counteracting hyperprolactinemia.

Influence of CYP2D6 Metabolizer Status on Risperidone and Paliperidone Tolerability in Children and Adolescents.

Background: Risperidone and, to a lesser extent, paliperidone are metabolized by CYP2D6; however, there are limited data related to variation in CYP2D6 phenotypes and the tolerability of these medications in children and adolescents. Furthermore, the impact of CYP2D6 on the association of risperidone and paliperidone with hyperprolactinemia in youth is not well understood. Methods: A retrospective chart review was performed in psychiatrically hospitalized children and adolescents prescribed risperidone (n = 263, age = 3-18 years, mean age = 13 ± 3 years, 49% female) or paliperidone (n = 124, age = 5-18 years, mean age = 15 ± 2 years, 44% female) who had CYP2D6 genotyping performed as part of routine care. CYP2D6 phenotypes were determined based on Clinical Pharmacogenetics Implementation Consortium guidelines and CYP2D6 inhibitors causing phenoconversion. Adverse effects were obtained from a review of the electronic health record, and patients were selected, in part, to enrich non-normal metabolizers. Results: Among risperidone-treated patients, 45% experienced an adverse effect, whereas 36% of paliperidone-treated patients experienced adverse effects. Discontinuation of risperidone due to lack of efficacy was more frequent in the CYP2D6 normal metabolizers and ultrarapid metabolizers compared with intermediate metabolizers (IMs) and phenoconverted poor metabolizers (pPMs) (54.5% vs. 32.7%, p < 0.001). Discontinuation due to weight gain was more common among risperidone- than paliperidone-treated patients (17% vs. 7%, p = 0.011). Among those taking paliperidone, CYP2D6 was associated with discontinuation due to side effects (p = 0.008), and youth with slower CYP2D6 metabolism (i.e., pPMs and IMs) were more likely to discontinue. Hyperprolactinemia was found in 10% of paliperidone-treated patients and 5% of risperidone-treated patients, and slower CYP2D6 metabolizers required higher risperidone doses to cause hyperprolactinemia (p = 0.011). Conclusions: CYP2D6 phenotype is associated with discontinuation of risperidone due to lack of efficacy and the dose of risperidone that induced hyperprolactinemia, as well as discontinuation of paliperidone due to adverse effects. Future studies should evaluate exposure-response and toxicity relationships in risperidone- and paliperidone-treated youth.

The polymorphisms of candidate pharmacokinetic and pharmacodynamic genes and their pharmacogenetic impacts on the effectiveness of risperidone maintenance therapy among Saudi children with autism.

BACKGROUND: Antipsychotics, including risperidone (RIS), are frequently indicated for various autism spectrum disorder (ASD) manifestations; however, "actionable" PGx testing in psychiatry regarding antipsychotic dosing and selection has limited applications in routine clinical practice because of the lack of standard guidelines, mostly due to the inconsistency and scarcity of genetic variant data. The current study is aimed at examining the association of RIS effectiveness, according to ABC-CV and CGI indexes, with relevant pharmacokinetics (PK) and pharmacodynamics (PD) genes. METHODS: Eighty-nine ASD children who received a consistent RIS-based regimen for at least 8 weeks were included. The Axiom PharmacoFocus Array technique was employed to generate accurate star allele-predicted phenotypes of 3 PK genes (CYP3A4, CYP3A5, and CYP2D6). Genotype calls for 5 candidate PD receptor genes (DRD1, DRD2, DRD3, HTR2C, and HTR2A) were obtained and reported as wild type, heterozygous, or homozygous for 11 variants. RESULTS: Based on the ABC total score, 42 (47.2%) children were classified as responders, while 47 (52.8%) were classified as nonresponders. Multivariate logistic regression analyses, adjusted for nongenetic factors, suggested nonsignificant impacts of the star allele-predicted phenotypes of all 3 PK genes on improvement in ASD symptoms or CGI scores. However, significant positive or negative associations of certain PD variants involved in dopaminergic and serotonergic pathways were observed with specific ASD core and noncore symptom subdomains. Our significant polymorphism findings, mainly those in DRD2 (rs1800497, rs1799978, and rs2734841), HTR2C (rs3813929), and HTR2A (rs6311), were largely consistent with earlier findings (predictors of RIS effectiveness in adult schizophrenia patients), confirming their validity for identifying ASD children with a greater likelihood of core symptom improvement compared to noncarriers/wild types. Other novel findings of this study, such as significant improvements in DRD3 rs167771 carriers, particularly in ABC total and lethargy/social withdrawal scores, and DRD1 rs1875964 homozygotes and DRD2 rs1079598 wild types in stereotypic behavior, warrant further verification in biochemical and clinical studies to confirm their feasibility for inclusion in a PGx panel. CONCLUSION: In conclusion, we provide evidence of potential genetic markers involved in clinical response variability to RIS therapy in ASD children. However, replication in prospective samples with greater ethnic diversity and sample sizes is necessary.

The Relevance of Integrating CYP2C19 Phenoconversion Effects into Clinical Pharmacogenetics.

INTRODUCTION: CYP2D6 and CYP2C19 functional status as defined by genotype is modulated by phenoconversion (PC) due to pharmacokinetic interactions. As of today, there is no data on the effect size of PC for CYP2C19 functional status. The primary aim of this study was to investigate the impact of PC on CYP2C19 functional status. METHODS: Two patient cohorts (total n=316; 44.2±15.4 years) were investigated for the functional enzyme status of CYP2C19 applying two different correction methods (PCBousman, PCHahn&Roll) as well as serum concentration and metabolite-to-parent ratio of venlafaxine, amitriptyline, mirtazapine, sertraline, escitalopram, risperidone, and quetiapine. RESULTS: There was a decrease in the number of normal metabolizers of CYP2C19 and an increase in the number of poor metabolizers. When controlled for age, sex, and, in the case of amitriptyline, venlafaxine, and risperidone, CYP2D6 functional enzyme status, an association was observed between the CYP2C19 phenotype/functional enzyme status and serum concentration of amitriptyline, sertraline, and escitalopram. DISCUSSION: PC of CYP2C19 changes phenotypes but does not improve correlations with serum concentrations. However, only a limited number of patients received perturbators of CYP2C19. Studies with large numbers of patients are still lacking, and thus, it cannot be decided if there are minor differences and which method of correction to use. For the time being, PC is relevant in individual patients treated with CYP2C19-affecting drugs, for example, esomeprazole. To ensure adequate serum concentrations in these patients, this study suggests the use of therapeutic drug monitoring.