Risperidone plasma concentrations are associated with side effects and effectiveness in children and adolescents with autism spectrum disorder

Mu-Suppression Neurofeedback Training Targeting the Mirror Neuron System: A Pilot Study

Neurofeedback training (NFT) is a promising adjuvant intervention method. The desynchronization of mu rhythm (8-13 Hz) in the electroencephalogram (EEG) over centro-parietal areas is known as a valid indicator of mirror neuron system (MNS) activation, which has been associated with social skills. Still, the effect of neurofeedback training on the MNS requires to be well investigated. The present study examined the possible impact of NFT with a mu suppression training protocol encompassing 15 NFT sessions (45 min each) on 16 healthy neurotypical participants. In separate pre- and post-training sessions, 64-channel EEG was recorded while participants (1) observed videos with various types of movements (including complex goal-directed hand movements and social interaction scenes) and (2) performed the "Reading the Mind in the Eyes Test" (RMET). EEG source reconstruction analysis revealed statistically significant mu suppression during hand movement observation across MNS-attributed fronto-parietal areas after NFT. The frequency analysis showed no significant mu suppression after NFT, despite the fact that numerical mu suppression appeared to be visible in a majority of participants during goal-directed hand movement observation. At the behavioral level, RMET accuracy scores did not suggest an effect of NFT on the ability to interpret subtle emotional expressions, although RMET response times were reduced after NFT. In conclusion, the present study exhibited preliminary and partial evidence that mu suppression NFT can induce mu suppression in MNS-attributed areas. More powerful experimental designs and longer training may be necessary to induce substantial and consistent mu suppression, particularly while observing social scenarios.

Relationship between plasma risperidone concentrations and clinical features in chronic schizophrenic patients in China

BACKGROUND

Prior studies have noted great variability in the plasma levels of risperidone (RIS). Plasma concentrations of RIS and its active moiety are highly variable and depend on absorption, metabolism, and other predictors of metabolic dysregulation; however, these factors are poorly understood and the association between metabolic change and change in psychopathology is uncertain.

AIM

To ascertain the characteristics of chronic schizophrenic patients treated with RIS, and to assess their relationship with plasma RIS levels.

METHODS

This was a descriptive cross-sectional study of 50 patients with a diagnosis of schizophrenic psychosis treated with RIS in a psychiatric service. The plasma concentrations of RIS and its metabolite 9-hydroxyrisperidone were determined by high performance liquid chromatography. The patients' demographic and clinical characteristics, and psychopathologies were assessed, and the associations between clinical variables and plasma levels of RIS were explored.

RESULTS

Male patients received higher doses of RIS than female ones, but plasma concentrations of RIS and risperidone + 9-hydroxyrisperidone (active moiety) were higher in female patients. Age and the mean scores of the general psychopathology subscale of the Positive and Negative Syndrome Scale (PANSS) were significantly positively correlated with plasma concentrations of risperidone + 9-hydroxyrisperidone adjusted for weight and dose in all 50 subjects. In male subjects, we found a statistically significant positive correlation between the concentrations of risperidone + 9-hydroxyrisperidone in plasma/(dose × kg) and age, mean PANSS negative subscale scores, mean PANSS general psychopathology subscale scores, and mean PANSS total scores.

CONCLUSION

Long-term use of RIS should be closely monitored in older patients and females to minimize the risk of high concentrations which could induce side effects.

Therapeutic Drug Monitoring to Optimize Risperidone Treatment in Children with Autism Spectrum Disorder

BACKGROUND

Risperidone is an atypical antipsychotic drug used to treat irritability and aggression in children and adolescents with autism spectrum disorder. In an earlier study, the sum trough concentration of risperidone and its metabolite (9-hydroxyrisperidone) was positively correlated with weight gain and effectiveness. The aim of this study was to determine the therapeutic window for risperidone sum trough concentrations that balances weight gain with treatment effectiveness in this population. In addition, the effect of therapeutic drug monitoring (TDM) on treatment optimization was simulated.

METHODS

In a retrospective cohort (n = 24 children), the target window for risperidone leading to the least increase in body mass index z-scores while retaining effectiveness as measured by the irritability subscale of the Aberrant Behavior Checklist was determined using receiver operating curve analysis. This target range was used to simulate the effect of TDM using a population PK model implemented in the software platform InsightRX. Dosing advice was based on plasma trough concentrations and the dose administered at 12 weeks to simulate whether more children would be on target at 24 weeks after the start of treatment.

RESULTS

A risperidone sum trough target range of 3.5-7.0 mcg/L would minimize increase in body mass index z-score and optimize effectiveness. Dosing advice using TDM and a population PK model would lead to a larger proportion of children achieving the target concentration range (62.5% versus 16.7%).

CONCLUSIONS

TDM may be a useful tool for optimizing risperidone treatment in children and adolescents with autism spectrum disorder.

Exploratory focused pharmacogenetic testing reveals novel markers associated with risperidone pharmacokinetics in Saudi children with autism

Background: Autism spectrum disorders (ASDs) encompass a broad range of phenotypes characterized by diverse neurological alterations. Genomic studies have revealed considerable overlap between the molecular mechanisms implicated in the etiology of ASD and genes involved in the pharmacokinetic (PK) and pharmacodynamic (PD) pathways of antipsychotic drugs employed in ASD management. Given the conflicting data originating from candidate PK or PD gene association studies in diverse ethnogeographic ASD populations, dosage individualization based on "actionable" pharmacogenetic (PGx) markers has limited application in clinical practice. Additionally, off-label use of different antipsychotics is an ongoing practice, which is justified given the shortage of approved cures, despite the lack of satisfactory evidence for its safety according to precision medicine. This exploratory study aimed to identify PGx markers predictive of risperidone (RIS) exposure in autistic Saudi children. Methods: This prospective cohort study enrolled 89 Saudi children with ASD treated with RIS-based antipsychotic therapy. Plasma levels of RIS and 9-OH-RIS were measured using a liquid chromatography-tandem mass spectrometry system. To enable focused exploratory testing, genotyping was performed with the Axiom PharmacoFocus Array, which included a collection of probe sets targeting PK/PD genes. A total of 720 PGx markers were included in the association analysis. Results: A total of 27 PGx variants were found to have a prominent impact on various RIS PK parameters; most were not located within the genes involved in the classical RIS PK pathway. Specifically, 8 markers in 7 genes were identified as the PGx markers with the strongest impact on RIS levels (p < 0.01). Four PGx variants in 3 genes were strongly associated with 9-OH-RIS levels, while 5 markers in 5 different genes explained the interindividual variability in the total active moiety. Notably, 6 CYP2D6 variants exhibited strong linkage disequilibrium; however, they significantly influenced only the metabolic ratio and had no considerable effects on the individual estimates of RIS, 9-OH-RIS, or the total active moiety. After correction for multiple testing, rs78998153 in UGT2B17 (which is highly expressed in the brain) remained the most significant PGx marker positively adjusting the metabolic ratio. For the first time, certain human leukocyte antigen (HLA) markers were found to enhance various RIS exposure parameters, which reinforces the gut-brain axis theory of ASD etiology and its suggested inflammatory impacts on drug bioavailability through modulation of the brain, gastrointestinal tract and/or hepatic expression of metabolizing enzymes and transporters. Conclusion: Our hypothesis-generating approach identified a broad spectrum of PGx markers that interactively influence RIS exposure in ASD children, which indicated the need for further validation in population PK modeling studies to define polygenic scores for antipsychotic efficacy and safety, which could facilitate personalized therapeutic decision-making in this complex neurodevelopmental condition.

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.

Risperidone plasma level, and its correlation with CYP2D6 gene polymorphism, clinical response and side effects in chronic schizophrenia patients

BACKGROUND

To explore the influence of CYP2D6 genetic polymorphism on risperidone metabolism, thereby affecting risperidone's effects and safeties in patients with chronic schizophrenia.

METHODS

Sixty-nine subjects with chronic schizophrenia treated with risperidone were recruited. CYP2D6 genotypes was determined using targeted sequencing and translated into phenotype using activity system. Risperidone plasma concentrations were measured using HPLC. Positive and Negative Symptom Scale (PANSS) and Brief Psychiatric Rating Scale (BPRS) were used to evaluate the existence and severity of psychiatric symptoms, Barnes Akathisia Scale (BAS) and Extrapyramidal Symptom Rating Scale (ESRS) for neurological side effects. Metabolic and endocrine status assess were also included.

RESULTS

The plasma drug concentrations varied hugely among individuals. Intermediate metabolizer (IM) group had higher plasma levels of RIP and dose corrected RIP concentration, RIP/9-OH-RIP ratio and C/D ratio than normal metabolizer (NM) group (p < 0.01). There was no statistic difference between responders and non-responders in dose-adjusted plasma concentrations and ratios of RIP/9-OH-RIP and C/D. The occurrence of EPS was related to active moiety levels in 4th week (p < 0.05). The prolactin (PRL) levels in two follow-ups were both significantly higher than baseline (p < 0.01). PRL change from baseline to week 4 and week 8 were both positively associated with active moiety concentration detected in week 4 (p < 0.05).

CONCLUSIONS

The risperidone plasma levels have great inter- and intraindividual variations, and are associated with the CYP2D6 phenotypes, as well as the changes in serum prolactin in patients diagnosed with chronic schizophrenia.

Co-occurring ASD Mediates Impact of ADHD on Atopic Dermatitis and Acne: A Retrospective Cohort Study

BACKGROUND

ADHD and ASD are associated with dermatologic manifestations, yet little research investigates co-occurring ADHD/ASD and common dermatologic conditions.

OBJECTIVE

To investigate associations between ADHD, ASD, acne vulgaris, and atopic dermatitis.

METHODS

Using de-identified patient records from the TriNetX database, we created four cohorts on ADHD diagnosis, ASD diagnosis, both, neither. Cohorts were separated into males and females. We balanced each cohort based on age, sex, race, and ethnicity to the baseline cohort with neither ASD or ADHD. Finally, we examined prevalence of acne and eczema.

RESULTS

The cohort sizes varied from 19,764 to 345,626. Compared to matched peers, males with ADHD or ADHD/ASD had increased prevalence of acne, and all neurodivergent males had increased prevalence of eczema. Females with ADHD had an increase in both. Females with ADHD/ASD had no significant differences, and females with ASD had a decreased risk of eczema.

LIMITATIONS

Due to database limitations, we are unable to: analyze symptom severity, skincare routine, or treatment adherence.

CONCLUSIONS

The decreased risk of eczema in females with ASD and lack of significant difference in incidence of acne or eczema in females with ADHD/ASD compared to matched peers suggests research into approaches to skincare in males versus females with ASD may provide clinically relevant insights.

The Frequency of CYP2D6 and CYP3A4/5 Genotypes and The Impact of Their Allele Translation and Phenoconversion-Predicted Enzyme Activity on Risperidone Pharmacokinetics in Saudi Children with Autism

Data on the role of CYP2D6 and CYP3A4/5 polymorphisms in relation to risperidone (RIS) pharmacokinetics (PK) in children are relatively limited and inconsistent. This is partially attributable to the limited coverage of CYP2D6 and CYP3A4/5 metabolizer phenotypes, particularly those of poor and ultrarapid metabolizers (PMs and UMs), which has led to calls for studies of populations with a non-European background that may carry variants that are less frequent in Europeans. Children ≤ 18 years old with at least 8 weeks of a RIS-based regimen were recruited from three autism centers in Riyadh, Saudi Arabia. The primary outcomes measured were plasma concentrations of RIS and 9-hydroxyrisperidone (9-OH-RIS) and their dose-adjusted (C/D) ratios as a function of phenotypes and activity score (AS). For accurate DNA genotyping, targeted pharmacogenomic testing with the Axiom PharmacoFocus Array was performed via examination of a broad collection of probesets targeting CYP2D6 and CYP3A4/5 variants. The frequency of genotypes/phenotypes and the impact of their allele translation and phenoconversion-predicted enzyme activity were examined. The final cohort included 83 individuals. The most common CYP2D6 phenotype in our population was normal metabolizers (NMs, 66.3%). Inconsistent with some previous studies, the three phenotypes of intermediate metabolizers (IMs), NMs, and UMs were significantly different in terms of RIS concentration, the RIS/9-OH-RIS ratio, the RIS C/D ratio and the 9-OH-RIS C/D ratio. According to AS analyses, there were statistically significant differences in the RIS concentration (P = 0.013), RIS/9-OH-RIS ratio (P < 0.001) and RIS C/D ratio (P = 0.030) when patients were categorized into AS ≤ 1 vs. AS > 1. None of the CYP3A4/5 star allele translated phenotypes revealed a significant influence on any of the RIS PK parameters. Notably, neither CYP2D6 nor CYP3A4/5 phenotyping demonstrated a significant impact on the total active moiety, suggesting that other gene variants could modulate RIS PK. The study confirmed the previously reported partial impact of the CYP2D6 gene on RIS PK. However, future studies using contemporary genotyping techniques targeting a wide range of variants in other candidate genes must be conducted to further examine their interactive effects on RIS PK and the clinical response.

Evaluation of the Effectiveness of Risperidone in Treating Breath-Holding Spells in Children

Objectives

Breath holding spells (BHS) are a type of syncope in children that is commonly seen in the first years of life. Although these attacks do not cause serious damage to the child's brain, in severe or repeated cases, they expose the brain to hypoxia and cause a lot of stress in parents. In these cases, the clinician should consider therapy. The purpose of this study is to investigate the effectiveness of Risperidone in the treatment of BHS in children visiting the neurology clinic of the Children's Medical Center Hospital.

Materials & Methods

In this randomized clinical trial, the statistical population included patients with the history of Breath Holding spells grades 2 to 3 (after ruling out of seizure disorders) over one year old, visiting the neurology clinic of Tehran Children's Medical Center in 2019. The subjects were randomly selected from patients visiting the clinic using a table of random numbers from the admit ion list. After providing the necessary explanations and obtaining informed consent from their parents, they were treated with low-dose Risperidone (maximum 1 mg) for three months. The patients were observed for three months in terms of frequency and severity of spells monthly.

Results

In this study, the median (25th and 75th percentile) age of subjects was 2.3 (2.0-2.6) years. Both the number and severity of seizures in the subjects had a statistically significant decrease in the period after treatment with Risperidone (P<0.001). The studied boys and girls experienced statistically significant decrease in terms of both the frequency of spells (P-value of 0.002 and 0.039) and intensity of seizures (P=0.016) and P=0.008), respectively after treatment with Risperidone. Also, in the studied children under 2 years old and over 2 years old, both the frequency (P=0.021 and P=0.004) and intensity of spells (P=0.008) 0.016 for subjects under and over 2 years, respectively) had a statistically significant decrease after treatment with risperidone compared to pretreatment.

Conclusion

According to the results of this study, it seems that both the frequency and the intensity of spells in children (regardless of gender and age group), experienced a statistically significant decrease after treatment with Risperidone. We suggest conducting a more comprehensive study considering a larger sample size in order to estimate this issue more correctly.

Towards precision dosing of aripiprazole in children and adolescents with autism spectrum disorder: Linking blood levels to weight gain and effectiveness

AIMS

Aripiprazole is one of the most commonly prescribed antipsychotic drugs to children and adolescents worldwide, but it is associated with serious side-effects, including weight gain. This study assessed the population pharmacokinetics of aripiprazole and its active metabolite and investigated the relationship between pharmacokinetic parameters and body mass index (BMI) in children and adolescents with autism spectrum disorder (ASD) and behavioural problems. Secondary outcomes were metabolic, endocrine, extrapyramidal and cardiac side-effects and drug effectiveness.

METHODS

Twenty-four children and adolescents (15 males, 9 females) aged 6-18 years were included in a 24-week prospective observational trial. Drug plasma concentrations, side-effects and drug effectiveness were measured at several time points during follow-up. Relevant pharmacokinetic covariates, including CYP2D6, CYP3A4, CYP3A5 and P-glycoprotein (ABCB1) genotypes, were determined. Nonlinear mixed-effects modelling (NONMEM®) was used for a population pharmacokinetic analysis with 92 aripiprazole and 91 dehydro-aripiprazole concentrations. Subsequently, model-based trough concentrations, maximum concentrations and 24-h area under the curves (AUCs) were analysed to predict outcomes using generalized and linear mixed-effects models.

RESULTS

For both aripiprazole and dehydro-aripiprazole, one-compartment models best described the measured concentrations, with albumin and BMI as significant covariates. Of all the pharmacokinetic parameters, higher sum (aripiprazole plus dehydro-aripiprazole) trough concentrations best predicted higher BMI z-scores (P < .001) and higher Hb1Ac levels (P = .03) during follow-up. No significant association was found between sum concentrations and effectiveness.

CONCLUSIONS

Our results indicate a threshold with regard to safety, which suggests that therapeutic drug monitoring of aripiprazole could potentially increase safety in children and adolescents with ASD and behavioural problems.

Individually tailored dosage regimen of full-spectrum Cannabis extracts for autistic core and comorbid symptoms: a real-life report of multi-symptomatic benefits

Autism Spectrum Disorders (ASD) may significantly impact the well-being of patients and their families. The therapeutic use of cannabis for ASD has gained interest due to its promising results and low side effects, but a consensus on treatment guidelines is lacking. In this study, we conducted a retrospective analysis of 20 patients with autistic symptoms who were treated with full-spectrum cannabis extracts (FCEs) in a response-based, individually-tailored dosage regimen. The daily dosage and relative proportions of cannabidiol (CBD) and tetrahydrocannabinol (THC) were adjusted based on treatment results following periodic clinical evaluation. Most patients (80%) were treated for a minimum of 6 months. We have used a novel, detailed online patient- or caregiver-reported outcome survey that inquired about core and comorbid symptoms, and quality of life. We also reviewed patients' clinical files, and no individual condition within the autistic spectrum was excluded. This real-life approach enabled us to gain a clearer appraisal of the ample scope of benefits that FCEs can provide for ASD patients and their families. Eighteen patients started with a CBD-rich FCE titrating protocol, and in three of them, the CBD-rich (CBD-dominant) FCE was gradually complemented with low doses of a THC-rich (THC-dominant) FCE based on observed effects. Two other patients have used throughout treatment a blend of two FCEs, one CBD-rich and the other THC-rich. The outcomes were mainly positive for most symptoms, and only one patient from each of the two above-mentioned situations displayed important side effects one who has used only CBD-rich FCE throughout the treatment, and another who has used a blend of CBD-Rich and THC-rich FCEs. Therefore, after FCE treatment, 18 out of 20 patients showed improvement in most core and comorbid symptoms of autism, and in quality of life for patients and their families. For them, side effects were mild and infrequent. Additionally, we show, for the first time, that allotriophagy (Pica) can be treated by FCEs. Other medications were reduced or completely discontinued in most cases. Based on our findings, we propose guidelines for individually tailored dosage regimens that may be adapted to locally available qualified FCEs and guide further clinical trials.

Therapeutic Impacts of Hyperbaric Oxygen Therapy and Risperidone on Children with Autism: A Clinical Trial

Introduction

In this research, we investigated any possible effect of receiving hyperbaric oxygen therapy (HBOT) or risperidone on the core symptoms of autism in children diagnosed with autism spectrum disorder (ASD).

Methods

This study was a randomized, controlled clinical trial in Minia and Assiut University hospitals in Egypt with three parallel groups. One hundred and eighty children with autism, aged 5-8 years were divided into three equal groups (n=60). Group 1 (G1) received 40 sessions of HBOT within two months, group 2 (G2) received risperidone (dose: 0.25 mg per day in children weighing less than 20 kg and 0.5 mg per day in cases weighing more) for six months, and group 3 (G3) as the control group, received a placebo for six months. The assessment was done using childhood autism rating scale (CARS) and autism treatment evaluation checklist (ATEC) at the beginning of the study (baseline) and after one year.

Results

The mean total CARS and ATEC scores significantly decreased (improved) by varying degrees in the three groups after a year of follow-up compared to the baseline scores, but the best results were found in G1, G2, and G3, respectively.

Conclusion

Using HBOT or risperidone is effective in treating the core symptoms of autism in children diagnosed with autism spectrum disorder, but using HBOT gives better results than risperidone therapy.

Highlights

Non-pharmacologic therapy can be used for the treatment of the core symptoms of autism.Both hyperbaric oxygen therapy and risperidone reduce the core symptoms of autism.Hyperbaric oxygen therapy gives better effects than risperidone in reducing the core symptoms of autism.

Plain Language Summary

Since the long-term use of drug therapy in children with autism leads to the occurrence of side effects in addition to the difficulty in complying with the drugs for long-term use, efforts have begun to use non-traditional alternative treatments, such as hyperbaric oxygen therapy. The current study assessed the therapeutic effect of hyperbaric oxygen therapy and risperidone on the core symptoms of autism. The results revealed that both hyperbaric oxygen therapy and risperidone reduced the core symptoms of autism, but hyperbaric oxygen therapy gave better therapeutic results than risperidone.

Clinical pharmacokinetics of antipsychotics in pediatric populations: a scoping review focusing on dosing regimen

INTRODUCTION

Achieving optimal clinical responses and minimizing side effects through precision dosing of antipsychotics in children and adolescents with psychiatric disorders remains a challenge. Identifying patient characteristics (covariates) that affect pharmacokinetics can inform more effective dosing strategies and ultimately improve patient outcomes. This review aims to provide greater insight into the impact of covariates on the clinical pharmacokinetics of antipsychotics in pediatric populations.

AREAS COVERED

A comprehensive literature search was conducted, and the main findings regarding the effects of the covariates on the pharmacokinetics of antipsychotics in children and adolescents are presented.

EXPERT OPINION

Our study highlights significant covariates, including age, sex, weight, CYP2D6 phenotype, co-medication, and smoking habits, which affect the pharmacokinetics of antipsychotics. However, the findings were generally limited by the small sample sizes of naturalistic, open-label, observational studies, and the homogeneous subgroups. Dosing based on weight and preemptive genotyping could prove beneficial for optimizing the dosing regimen in pediatric populations. Future research is needed to refine dosing recommendations and establish therapeutic reference ranges critical for precision dosing and Therapeutic Drug Monitoring (TDM). The integration of individual patient characteristics with TDM can further optimize the efficacy and safety of antipsychotics for each patient.

Guava-fruit based synthesis of carbon quantum dots for spectrofluorometric quantitative analysis of risperidone in spiked human plasma and pharmaceutical dosage forms

Autism is one of the most pressing issues facing the international community in recent years, particularly in Middle Eastern countries. Risperidone is a selective serotonin type 2 and dopamine type 2 receptor antagonist. It is the most administered antipsychotic medication in children with autism-related behavioral disorders. Therapeutic monitoring of risperidone may improve safety and efficacy in autistic individuals. The main objective of this work was to develop a highly sensitive green fitted method for the determination of risperidone in the plasma matrix and pharmaceutical dosage forms. Novel water-soluble N-carbon quantum dots were synthesized from guava fruit, a natural green precursor, and used for determination of risperidone based on quenching fluorescence spectroscopy phenomena. The synthesized dots were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. The synthesized N-carbon quantum dots exhibited aquantum yield of 26.12% and showed a strong emission fluorescence peak at 475 nm when excited at 380 nm. The fluorescence intensity of the N-carbon quantum dots decreased with increasing risperidone concentration, indicating that the fluorescence quenching was concentration dependent. The presented method was carefully optimized and validated according to the guidelines of ICH, and it demonstrated good linearity in a concentration range of 5-150 ng mL-1. With a LOD of 1.379 ng mL-1 and a LOQ of 4.108 ng mL-1, the technique was extremely sensitive. Due to the high sensitivity of the proposed method, it could be effectively used for the determination of risperidone in the plasma matrix. The proposed method was compared with the previously reported HPLC method in terms of sensitivity and green chemistry metrics. The proposed method proved to be more sensitive and compatible with the principles of green analytical chemistry.

Injectable In-Situ Forming Depot Based on PLGA and PLGA-PEG-PLGA for Sustained-Release of Risperidone: In Vitro Evaluation and Pharmacokinetics in Rabbits

In the current research, novel drug delivery systems based on in situ forming gel (ISFG) (PLGA-PEG-PLGA) and in situ forming implant (ISFI) (PLGA) were developed for one-month risperidone delivery. In vitro release evaluation, pharmacokinetics, and histopathology studies of ISFI, ISFG, and Risperdal CONSTA^® were compared in rabbits. Formulation containing 50% (w/w %) of PLGA-PEG-PLGA triblock revealed sustained release for about one month. Scanning electron microscopy (SEM) showed a porous structure for ISFI, while a structure with fewer pores was observed in the triblock. Cell viability in ISFG formulation in the first days was more than ISFI due to the gradual release of NMP to the release medium. Pharmacokinetic data displayed that optimal PLGA-PEG-PLGA creates a consistent serum level in vitro and in vivo through 30 days, and histopathology results revealed nearly slight to moderate pathological signs in the rabbit's organs. The shelf life of the accelerated stability test didn't affect the results of the release rate test and demonstrated stability in 24 months. This research confirms the better potential of the ISFG system compared with ISFI and Risperdal CONSTA^®, which would increase patients' compliance and avoid problems of further oral therapy.

The effect of therapeutic drug monitoring of risperidone and aripiprazole on weight gain in children and adolescents: the SPACe 2: STAR (trial) protocol of an international multicentre randomised controlled trial

BACKGROUND

Antipsychotic drugs are an important part of the treatment of irritability and aggression in children with an autism spectrum disorder (ASD). However, significant weight gain and metabolic disturbances are clinically relevant side effects of antipsychotic use in children. In the SPACe study, we showed positive correlations between both risperidone and aripiprazole plasma trough concentrations and weight gain over a 6-month period. The trial SPACe 2: STAR is designed as a follow-up study, in which we aim to research whether therapeutic drug monitoring in clinical practice can prevent severe weight gain, while retaining clinical effectiveness.

METHODS

SPACe 2: STAR is an international, multicentre, randomised controlled trial (RCT). One hundred forty children aged 6 to 18 who are about to start risperidone or aripiprazole treatment for ASD related behavioural problems will be randomised into one of two groups: a therapeutic drug monitoring (TDM) group, and a care as usual (CAU) group. Participants will be assessed at baseline and 4, 10, 24, and 52 weeks follow-up. In the TDM group, physicians will receive dosing advice based on plasma levels of risperidone and aripiprazole and its metabolites at 4 and 10 weeks. Plasma levels will be measured in dried blood spots (DBS). The primary outcome will be BMI z-score at 24 weeks after start of antipsychotic treatment. Among the secondary outcomes are effectiveness, metabolic laboratory measurements, levels of prolactin, leptin and ghrelin, extrapyramidal side effects, and quality of life.

DISCUSSION

This will be the first RCT evaluating the effect of TDM of antipsychotic drugs in children and adolescents. Thus, findings from SPACe 2: STAR will be of great value in optimising treatment in this vulnerable population.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05146245. EudraCT number: 2020-005450-18. Sponsor protocol name: SPACe2STAR. Registered 8 June 2021. Protocol Version 6, Protocol date: 18 august 2022.

Serious Adverse Drug Reactions to Antipsychotics in Minors with Multiple Disabilities: Preventability and Potential Cost Savings by Therapeutic Drug Monitoring

INTRODUCTION

Children and adolescents with multiple disabilities and mental disorders (CAMD) are frequently treated with antipsychotic drugs. However, CAMD are particularly susceptible to serious adverse drug reactions (sADRs). This retrospective study examined the frequency of sADRs to antipsychotics in CAMD. Further, the potential preventability of these sADRs through therapeutic drug monitoring (TDM) and the potential socio-economic benefits of TDM were explored.

METHODS

Routine clinical data of all patients treated at a specialized psychiatric clinic for CAMD between January 2017 and December 2018 were retrospectively examined. Data on the occurrence of sADRs (definition according to the European Medicines Agency), their causality with antipsychotics, as well as their preventability (Schumock criteria) were extracted from patient files. The prolongation of the hospital stay due to sADRs was calculated, and the cost savings were estimated if TDM had been applied. The data were based on a subsample of the KiDSafe project, supported by the Innovation Fund of the Joint Federal Committee, grant number 01NVF16021.

RESULTS

One hundred two CAMD who were administered at least one antipsychotic drug during inpatient treatment were identified. Of these patients, 22 (21.6%) sADRs with a possible causal relationship with the antipsychotic treatment were documented. Eleven sADRs (50%) could potentially have been prevented through TDM. Mitigating sADRs through TDM likely would have prevented prolonged hospital stays and thus conferred considerable savings for health insurance companies.

DISCUSSION

The routine implementation of TDM is urgently recommended for antipsychotic treatment in CAMD to increase drug therapy safety.

Core Signs and Symptoms in Children with Autism Spectrum Disorder Improved after Starting Risperidone and Aripiprazole in Combination with Standard Supportive Therapies: A Large, Single-Center, Retrospective Case Series

Background: There are a number of medications prescribed to address comorbid challenging behaviors in children with autism spectrum disorder (ASD), including risperidone and aripiprazole. This retrospective case series reports the use of these drugs in children aged 2 to 13 years. Methodology: A total of 82 children (mean age, 5 years; 79% male) with ASD treated at the Kids Neuro Clinic and Rehab Center in Dubai between January 2020 and September 2021 were included in this retrospective case series. All patients had comorbid challenging behaviors that were resistant to standard supportive therapies alone and warranted pharmacological intervention. The Childhood Autism Rating Scale—2nd Edition Standard form (CARS2-ST) and the Clinical Global Impression (CGI)—Severity (CGI-S) and CGI—Improvement (CGI-I) scales were used to assess the severity of ASD at baseline and to monitor response to treatment with risperidone or aripiprazole. Results: Besides the expected improvement in comorbid challenging behaviors, 79/82 patients (96%) attained a CGI-I score of 2 or 1 following treatment, and 35/82 patients (43%) achieved both a CGI-I score of 1 and minimal-to-no symptoms as per the CARS2-ST test, with complete resolution of their ASD signs and symptoms. The differences in the overall mean CARS2-ST and CGI-S scores pre- and post-treatment were statistically significant (Z = −7.86, p < 0.0001 for both), with pre- and post-treatment mean values of 42 and 23 for CARS2-ST, respectively, and 6 and 2 for CGI-S, respectively. The main side effects were asymptomatic elevated prolactin (n = 12) and excessive weight gain (n = 2). Conclusions: ASD core symptoms and comorbid behaviors in young children improved following chronic treatment with antipsychotic medications, either with or without medications for attention deficit hyperactivity disorder, when combined with standard supportive therapies. Double-blind, placebo-controlled clinical trials are needed to verify these findings.

Microsampling to support pharmacokinetic clinical studies in pediatrics

BACKGROUND

Conventional sampling for pharmacokinetic clinical studies requires removal of large blood volumes from patients. This can result in a physiological/emotional burden for children. Microsampling to support pharmacokinetic clinical studies in pediatrics may reduce this burden.

METHODS

Parents/guardians and bedside nurses completed a questionnaire describing their perception of the use of microsampling compared to conventional sampling to collect blood samples, based on their child's participation or their own role within a paired-sample pharmacokinetic clinical study. Responses were based on a seven-point Likert scale and were analyzed using frequency distributions.

RESULTS

Fifty-one parents/guardians and seven bedside nurses completed a questionnaire. Parents/guardians (96%) and bedside nurses (100%) indicated that microsampling was highly acceptable and recommended as a method for collecting blood samples for pediatric patients. Responding to a question about the child indicating pain during the blood sampling procedure, 61% of parent/guardians reported no pain in their children, 14% remained neutral, and 26% reported that their child indicated pain; 71% of the bedside nurses slightly agreed that the children indicated pain.

CONCLUSIONS

This study strongly suggests that parents/guardians and bedside nurses prefer microsampling to conventional sampling to conduct pediatric pharmacokinetic clinical studies. Employing microsampling may support increased participation by children in these studies.

IMPACT

Pharmacokinetic clinical studies require the withdrawal of blood samples at multiple times during a dosing interval. This can result in a physiological or emotional burden, particularly for neonates or pediatric patients. Microsampling offers an important opportunity for pharmacokinetic clinical studies in vulnerable patient populations, where smaller sample volumes can be collected. However, microsampling is not commonly used in clinical studies. Understanding the perceptions of parents/guardians and bedside nurses about microsampling may ascertain if this technique offers an improvement to conventional blood sample collection to perform pharmacokinetic clinical studies for pediatric patients.

External Evaluation of Risperidone Population Pharmacokinetic Models Using Opportunistic Pediatric Data

Risperidone is approved to treat schizophrenia in adolescents and autistic disorder and bipolar mania in children and adolescents. It is also used off-label in younger children for various psychiatric disorders. Several population pharmacokinetic models of risperidone and 9-OH-risperidone have been published. The objectives of this study were to assess whether opportunistically collected pediatric data can be used to evaluate risperidone population pharmacokinetic models externally and to identify a robust model for precision dosing in children. A total of 103 concentrations of risperidone and 112 concentrations of 9-OH-risperidone, collected from 62 pediatric patients (0.16–16.8 years of age), were used in the present study. The predictive performance of five published population pharmacokinetic models (four joint parent-metabolite models and one parent only) was assessed for accuracy and precision of the predictions using statistical criteria, goodness of fit plots, prediction-corrected visual predictive checks (pcVPCs), and normalized prediction distribution errors (NPDEs). The tested models produced similarly precise predictions (Root Mean Square Error [RMSE]) ranging from 0.021 to 0.027 nmol/ml for risperidone and 0.053–0.065 nmol/ml for 9-OH-risperidone). However, one of the models (a one-compartment mixture model with clearance estimated for three subpopulations) developed with a rich dataset presented fewer biases (Mean Percent Error [MPE, %] of 1.0% vs. 101.4, 146.9, 260.4, and 292.4%) for risperidone. In contrast, a model developed with fewer data and a more similar population to the one used for the external evaluation presented fewer biases for 9-OH-risperidone (MPE: 17% vs. 69.9, 47.8, and 82.9%). None of the models evaluated seemed to be generalizable to the population used in this analysis. All the models had a modest predictive performance, potentially suggesting that sources of inter-individual variability were not entirely captured and that opportunistic data from a highly heterogeneous population are likely not the most appropriate data to evaluate risperidone models externally.

Therapeutic drug monitoring in children and adolescents with schizophrenia and other psychotic disorders using risperidone

Risperidone is commonly used to treat different psychiatric disorders worldwide. Knowledge on dose–concentration relationships of risperidone treatment in children and adolescents with schizophrenia or other psychotic disorders is, however, scarce and no age-specific therapeutic ranges have been established yet. Multicenter data of a therapeutic drug monitoring service were analyzed to evaluate the relationship between risperidone dose and serum concentration of the active moiety (risperidone (RIS) plus its main metabolite 9-hydroxyrisperidone (9-OH-RIS)) in children and adolescents with psychotic disorders. Patient characteristics, doses, serum concentrations and therapeutic outcomes were assessed by standardized measures. The study also aimed to evaluate whether the therapeutic reference range for adults (20–60 ng/ml) is applicable for minors. In the 64 patients (aged 11–18 years) included, a positive correlation between daily dose and the active moiety (RIS_am) concentration was found (r_s = 0.49, p = 0.001) with variation in dose explaining 24% (r_s² = 0.240) of the variability in serum concentrations. While the RIS_am concentration showed no difference, RIS as well 9-OH-RIS concentrations and the parent to metabolite ratio varied significantly in patients with co-medication of a CYP2D6 inhibitor. Patients with extrapyramidal symptoms (EPS) had on average higher RISam concentrations than patients without (p = 0.05). Considering EPS, the upper threshold of the therapeutic range of RIS_am was determined to be 33 ng/ml. A rough estimation method also indicated a possibly decreased lower limit of the preliminary therapeutic range in minors compared to adults. These preliminary data may contribute to the definition of a therapeutic window in children and adolescents with schizophrenic disorders treated with risperidone. TDM is recommended in this vulnerable population to prevent concentration-related adverse drug reactions.

[Therapeutic drug monitoring to optimize psychopharmacotherapy in children and adolescents - Update and guidelines for practice]

Therapeutic drug monitoring to optimize psychopharmacotherapy in children and adolescents - Update and guidelines for practice Abstract. Despite the improved evidence base, many uncertainties remain in child and adolescent psychiatric pharmacotherapy about the efficacy and tolerability of drugs, which are often prescribed off-label or in combination therapy in this age group. Because medium- to long-term use is unavoidable in many cases, clinicians should minimize adverse drug reactions as far as possible and tailor an effective dosage to the individual characteristics of the patient. Not only are children and adolescents particularly vulnerable to certain adverse drug effects, they are also exposed to iatrogenic risks from dosing or application errors, which can lead to under- or overdosing with correspondingly negative effects on the success of the therapy. In addition to determining a strict indication, it is therefore essential to establish precise dosage and systematic monitoring of the safety of the psychopharmacotherapy. This article introduces therapeutic drug monitoring as a useful clinical tool and describes how its correct application in practice can improve the efficacy as well as the safety and tolerability of psychotropic therapy in children and adolescents for the immediate benefit of patients. Keywords: Psychopharmacotherapy, adverse drug reactions, pharmacovigilance, therapeutic drug monitoring, quality assurance.

Pharmacological and dietary-supplement treatments for autism spectrum disorder: a systematic review and network meta-analysis

Background

There is still no approved medication for the core symptoms of autism spectrum disorder (ASD). This network meta-analysis investigated pharmacological and dietary-supplement treatments for ASD.

Methods

We searched for randomized-controlled-trials (RCTs) with a minimum duration of seven days in ClinicalTrials.gov, EMBASE, MEDLINE, PsycINFO, WHO-ICTRP (from inception up to July 8, 2018), CENTRAL and PubMed (up to November 3, 2021). The co-primary outcomes were core symptoms (social-communication difficulties-SCD, repetitive behaviors-RB, overall core symptoms-OCS) measured by validated scales and standardized-mean-differences (SMDs). Associated symptoms, e.g., irritability/aggression and attention-deficit/hyperactivity disorder (ADHD) symptoms, dropouts and important side-effects, were investigated as secondary outcomes. Studies in children/adolescents and adults were analyzed separately in random-effects pairwise and network meta-analyses.

Results

We analyzed data for 41 drugs and 17 dietary-supplements, from 125 RCTs (n = 7450 participants) in children/adolescents and 18 RCTs (n = 1104) in adults. The following medications could improve at least one core symptom domain in comparison with placebo: aripiprazole (k = 6 studies in analysis, SCD: SMD = 0.27 95% CI [0.09, 0.44], RB: 0.48 [0.26, 0.70]), atomoxetine (k = 3, RB:0.49 [0.18, 0.80]), bumetanide (k = 4, RB: 0.35 [0.09, 0.62], OCS: 0.61 [0.31, 0.91]), and risperidone (k = 4, SCM: 0.31 [0.06, 0.55], RB: 0.60 [0.29, 0.90]; k = 3, OCS: 1.18 [0.75, 1.61]) in children/adolescents; fluoxetine (k = 1, RB: 1.20 [0.45, 1.96]), fluvoxamine (k = 1, RB: 1.04 [0.27, 1.81]), oxytocin (k = 6, RB:0.41 [0.16, 0.66]) and risperidone (k = 1, RB: 0.97 [0.21,1.74]) in adults. There were some indications of improvement by carnosine, haloperidol, folinic acid, guanfacine, omega-3-fatty-acids, probiotics, sulforaphane, tideglusib and valproate, yet imprecise and not robust. Confidence in these estimates was very low or low, except moderate for oxytocin. Medications differed substantially in improving associated symptoms, and in their side-effect profiles.

Limitations

Most of the studies were inadequately powered (sample sizes of 20–80 participants), with short duration (8–13 weeks), and about a third focused on associated symptoms. Networks were mainly star-shaped, and there were indications of reporting bias. There was no optimal rating scale measuring change in core symptoms.

Conclusions

Some medications could improve core symptoms, although this could be likely secondary to the improvement of associated symptoms. Evidence on their efficacy and safety is preliminary; therefore, routine prescription of medications for the core symptoms cannot be recommended.

Trial registration PROSPERO-ID CRD42019125317.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-022-00488-4.

CYP2D6 Genetic Variation and Antipsychotic-Induced Weight Gain: A Systematic Review and Meta-Analysis

BACKGROUND

Antipsychotic-induced weight gain is a contributing factor in the reduced life expectancy reported amongst people with psychotic disorders. CYP2D6 is a liver enzyme involved in the metabolism of many commonly used antipsychotic medications. We investigated if CYP2D6 genetic variation influenced weight or BMI among people taking antipsychotic treatment.

METHODS

We conducted a systematic review and a random effects meta-analysis of publications in Pubmed, Embase, PsychInfo, and CENTRAAL that had BMI and/or weight measurements of patients on long-term antipsychotics by their CYP2D6-defined metabolic groups (poor, intermediate, normal/extensive, and ultra-rapid metabolizers, UMs).

RESULTS

Twelve studies were included in the systematic review. All cohort studies suggested that the presence of reduced-function or non-functional alleles for CYP2D6 was associated with greater antipsychotic-induced weight gain, whereas most cross-sectional studies did not find any significant associations. Seventeen studies were included in the meta-analysis with clinical data of 2,041 patients, including 93 poor metabolizers (PMs), 633 intermediate metabolizers (IMs), 1,272 normal metabolizers (NMs), and 30 UMs. Overall, we did not find associations in any of the comparisons made. The estimated pooled standardized differences for the following comparisons were (i) PM versus NM; weight = -0.07 (95%CI: -0.49 to 0.35, p = 0.74), BMI = 0.40 (95%CI: -0.19 to 0.99, p = 0.19). (ii) IM versus NM; weight = 0.09 (95% CI: -0.04 to 0.22, p = 0.16) and BMI = 0.09 (95% CI: -0.24 to 0.41, p = 0.60). (iii) UM versus EM; weight = 0.01 (95% CI: -0.37 to 0.40, p = 0.94) and BMI = -0.08 (95%CI: -0.57 to 0.42, p = 0.77).

CONCLUSION

Our systematic review of cohort studies suggested that CYP2D6 poor metabolizers have higher BMI than normal metabolizers, but the data of cross-sectional studies and the meta-analysis did not show this association. Although our review and meta-analysis constitutes one of the largest studies with comprehensively genotyped samples, the literature is still limited by small numbers of participants with genetic variants resulting in poor or UMs status. We need further studies with larger numbers of extreme metabolizers to establish its clinical utility in antipsychotic treatment. CYP2D6 is a key gene for personalized prescribing in mental health.

Risperidone-associated enuresis—a case report

Background

Risperidone has been reported to be effective in treating both the positive and negative symptoms of schizophrenia, aggression, and behavioral disorders. While the metabolic side effect profile of this medication has been broadly studied, studies related to this medication’s bladder effects are relatively rare. We present a case of risperidone-induced enuresis in an adult male with schizophrenia that resolved upon discontinuation of the offending medication.

Case presentation

We describe a case of a 32-year-old man with a primary psychotic disorder who developed debilitating enuresis secondary to taking risperidone. Enuresis resolved upon switching to Seroquel.

Conclusion

Enuresis secondary to risperidone is not commonly discussed prior to initiation by the treating psychiatrist however can be debilitating. Discussing this potential side effect is critical to informed decision making on the patient’s part.

Muscle strength and executive function in children and adolescents with autism spectrum disorder

The development of effective (non‐pharmacological) treatment approaches for executive dysfunction in autism spectrum disorder (ASD) requires evidence that factors influencing this domain can be modified by behavioral interventions. The present cross‐sectional study investigated the relative associations of ASD, muscle strength and body mass index with executive function and information processing among the Healthy Brain Network cohort. Patients with ASD (N = 174) and healthy peers (N = 202) aged 5 to 18 years completed cognitive tasks of the NIH toolbox (Pattern Comparison, Flanker, List Sorting, Card Sorting) to assess core components of executive function and information processing. Additionally, anthropometrics and muscle strength were collected from selected items (push‐ups, curl‐ups, trunk lift, and grip strength) of the Fitnessgram battery. Based on structural equation modeling, ASD was related to impaired muscle strength and executive function, when confounders (age, sex, pubertal status, and socioeconomic status) were accounted for. Muscle strength further showed independent contributions to information processing and executive function. This association was moderated by ASD, so that higher muscle strength was related to higher executive function in ASD patients only. The present findings provide a first indication that the promotion of muscle strength may have the potential to generally enhance information processing and to reduce ASD‐related executive dysfunction in children and adolescents.

Psychotropic medication prescribing in people with autism spectrum disorders with and without psychiatric comorbidity

Autism spectrum disorders (ASDs) are a group of lifelong neurodevelopmental disorders characterised by difficulties in social interactions and social communication, and restricted and repetitive behaviours. Relative to the general population, individuals with ASDs are likely to be overrepresented in secure psychiatric care and custodial settings. Outcomes vary and can be problematic in the context of co-occurring intellectual disability, psychiatric disorder and challenging behaviours. To date, there is little in the way of specialised clinical guidance on the prescription of psychotropic medicines for individuals with ASDs, particularly information on any differences in efficacy and/or tolerability of specific medications. This review summarises the key research to date on the prescription of psychotropic medication in ASD with and without comorbid psychiatric or neurodevelopmental disorders, within the context of the existing clinical guidance. Some critical analysis is provided to aid clinicians in following a safe, effective and individualised approach to prescribing for people with ASDs.

CYP2D6 and Antipsychotic Treatment Outcomes in Children and Youth: A Systematic Review

Objective: To systematically review the impact of CYP2D6 genetic variation on antipsychotic pharmacokinetics, efficacy, and adverse drug reactions among children and youth. Method: The published literature was systematically searched in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations and critically evaluated using standardized tools and consensus criteria. Results: A total of 20 eligible studies comprising 1078 children and youth were evaluated. The included studies were of fair to moderate quality and included mostly males, individuals of European ancestry, and those treated with risperidone. CYP2D6 poor metabolizers (PMs) were consistently shown to have increased concentrations of risperidone relative to normal metabolizers (NMs). PMs were also consistently shown to have a greater propensity to experience antipsychotic (primarily risperidone) associated adverse drug reactions relative to NMs. However, robust evidence for an association between CYP2D6 and efficacy was less apparent. Conclusion and Clinical Significance: The current knowledge base suggests that CYP2D6 genetic variation has an appreciable impact on antipsychotic pharmacokinetics and the propensity for adverse drug reactions, particularly among children receiving risperidone treatment. However, several limitations with the current literature (e.g., sample sizes, study design, sample heterogeneity) should be addressed in future studies. Assuming that future studies support the link between CYP2D6 genetic variation and antipsychotic outcomes, we would anticipate an increase in the implementation of CYP2D6-guided antipsychotic drug selection and dose optimization in child and adolescent psychiatric services.