Meta-analysis: the effects of smoking on the disposition of two commonly used antipsychotic agents, olanzapine and clozapine

Increased antipsychotic drug concentration in hospitalized patients with mental disorders following COVID-19 infection: a call for attention

Purpose

Examine the alterations in antipsychotic concentrations following coronavirus disease-2019 (COVID-19) infection among hospitalized patients with mental disorders and conduct an analysis of the factors influencing these changes.

Methods

Data were collected from inpatients at Beijing Huilongguan Hospital between December 12, 2022, and January 11, 2023, pre- and post-COVID-19. Based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, 329 inpatients with mental disorders were included (3 with incomplete data excluded). Primary outcomes assessed changes in antipsychotic concentrations pre- and post-COVID-19, while secondary outcomes examined factors linked to concentration increases and antipsychotic dose adjustments.

Results

Clozapine (P < 0.001), aripiprazole (P < 0.001), quetiapine (P = 0.005), olanzapine (P < 0.001), risperidone (P < 0.001), and paliperidone (P < 0.001) concentrations increased post-COVID-19 in patients with mental disorders. Notably, clozapine concentration surpassing pre-infection levels was highest. Clozapine users were more likely to adjust their dose (50.4%) compared to olanzapine (17.5%) and other antipsychotics. Moreover, traditional Chinese patent medicines and antibiotics during COVID-19 infection were associated with antipsychotic reduction or withdrawal (OR = 2.06, P = 0.0247; OR = 7.53, P = 0.0024, respectively).

Conclusion

Antipsychotic concentrations in hospitalized patients with mental disorders increased after COVID-19 infection, that may be related not only to COVID-19, but also to the use of Chinese patent medicines during infection. The pre-infection concentration and types of antipsychotics, patient's gender, and combination of traditional Chinese medicine or antibiotics, were factors found to correlate with increased drug concentrations and necessitate dose adjustments.

Optimisation of pharmacotherapy in psychiatry through therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests: focus on antipsychotics

BACKGROUND

For psychotic disorders (i.e. schizophrenia), pharmacotherapy plays a key role in controlling acute and long-term symptoms. To find the optimal individual dose and dosage strategy, specialized tools are used. Three tools have been proven useful to personalize drug treatments: therapeutic drug monitoring (TDM) of drug levels, pharmacogenetic testing (PG), and molecular neuroimaging.

METHODS

In these Guidelines, we provide an in-depth review of pharmacokinetics, pharmacodynamics, and pharmacogenetics for 50 antipsychotics. Over 30 international experts in psychiatry selected studies that have measured drug concentrations in the blood (TDM), gene polymorphisms of enzymes involved in drug metabolism, or receptor/transporter occupancies in the brain (positron emission tomography (PET)).

RESULTS

Study results strongly support the use of TDM and the cytochrome P450 (CYP) genotyping and/or phenotyping to guide drug therapies. Evidence-based target ranges are available for titrating drug doses that are often supported by PET findings.

CONCLUSION

All three tools discussed in these Guidelines are essential for drug treatment. TDM goes well beyond typical indications such as unclear compliance and polypharmacy. Despite its enormous potential to optimize treatment effects, minimize side effects and ultimately reduce the global burden of diseases, personalized drug treatment has not yet become the standard of care in psychiatry.

Once-daily versus divided dosing regimens of clozapine: A cross-sectional study in Singapore

INTRODUCTION

Clozapine is recognized as the gold standard medication for treatment-resistant schizophrenia. Despite the general recommendation of administering in a divided dosing regimen, clozapine is often prescribed once daily at night in clinical practice. This study aims to compare patient characteristics, psychiatric symptoms, side effects, and plasma concentration of clozapine between once-daily dosing and divided dosing regimens.

METHODS

This cross-sectional study included 159 participants with treatment-resistant schizophrenia or schizoaffective disorder. Participant's demographic information, anthropometric data, and medical history were collected. Their psychiatric symptoms, cognition, functioning, and side effects were evaluated.

RESULTS

Once-daily dosing regimen was associated with younger age and competitive employment. Lower clinical symptom severity, better functioning and cognitive performance were observed in the once-daily dosing group. Lower daily dose of clozapine, trough plasma concentrations of clozapine and norclozapine were also significantly associated with once-daily dosing regimen.

CONCLUSION

The study results support once-daily dosing of clozapine as a viable option to selected patients in clinical practice, as no association of severe symptoms or side effects were associated with once-daily dosing regimen. More studies are needed to examine the relationship between clinical outcomes and clozapine dosing regimen.

Polygenetic risk scores and phenotypic constellations of obsessive-compulsive disorder in clozapine-treated schizophrenia

Obsessive-compulsive symptoms (OCS) are frequently observed in individuals with schizophrenia (SCZ) treated with clozapine (CLZ). This study aimed to analyze prevalence of OCS and obsessive-compulsive disorder (OCD) in this subgroup and find possible correlations with different phenotypes. Additionally, this is the first study to examine polygenetic risk scores (PRS) in individuals with SCZ and OCS. A multicenter cohort of 91 individuals with SCZ who were treated with CLZ was recruited and clinically and genetically assessed. Symptom severity was examined using the Positive and Negative Symptom Scale (PANSS), Clinical Global Impression Scale (CGI), the Calgary Depression Scale for Schizophrenia (CDSS), Global Assessment of Functioning Scale (GAF) and Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Participants were divided into subgroups based on phenotypic OCS or OCD using Y-BOCS scores. Genomic-wide data were generated, and PRS analyses were performed to evaluate the association between either phenotypic OCD or OCS severity and genotype-predicted predisposition for OCD, SCZ, cross-disorder, and CLZ/norclozapine (NorCLZ) ratio, CLZ metabolism and NorCLZ metabolism. OCS and OCD were frequent comorbidities in our sample of CLZ-treated SCZ individuals, with a prevalence of 39.6% and 27.5%, respectively. Furthermore, the Y-BOCS total score correlated positively with the duration of CLZ treatment in years (r = 0.28; p = 0.008) and the PANSS general psychopathology subscale score (r = 0.23; p = 0.028). A significant correlation was found between OCD occurrence and PRS for CLZ metabolism. We found no correlation between OCS severity and PRS for CLZ metabolism. We found no correlation for either OCD or OCS and PRS for OCD, cross-disorder, SCZ, CLZ/NorCLZ ratio or NorCLZ metabolism. Our study was able to replicate previous findings on clinical characteristics of CLZ-treated SCZ individuals. OCS is a frequent comorbidity in this cohort and is correlated with CLZ treatment duration in years and PANSS general psychopathology subscale score. We found a correlation between OCD and PRS for CLZ metabolism, which should be interpreted as incidental for now. Future research is necessary to replicate significant findings and to assess possible genetic predisposition of CLZ-treated individuals with SCZ to OCS/OCD. Limitations attributed to the small sample size or the inclusion of subjects on co-medication must be considered. If the association between OCD and PRS for CLZ metabolism can be replicated, it should be further evaluated if CYP1A2 alteration, respectively lower CLZ plasma level, is relevant for OCD development.

Evidence for Therapeutic Drug Monitoring of Atypical Antipsychotics

Second-generation antipsychotics (SGAs), also known as atypical antipsychotics, are a newer class of antipsychotic drugs used to treat schizophrenia, bipolar disorder, and related psychiatric conditions. The plasma concentration of antipsychotic drugs is a valid measure of the drug at its primary target structure in the brain, and therefore determines the efficacy and safety of these drugs. However, despite the well-known high variability in pharmacokinetics of these substances, psychiatric medication is usually administered in uniform dosage schedules. Therapeutic drug monitoring (TDM), as the specific method that can help personalised medicine in dose adjustment according to the characteristics of the individual patient, minimizing the risk of toxicity, monitoring adherence, and increasing cost-effectiveness in the treatment, thus seems to be an elegant tool to solve this problem. Non-response to therapeutic doses, uncertain adherence to medication, suboptimal tolerability, or pharmacokinetic drug-drug interactions are typical indications for TDM of SGAs. This review aims to summarize an overview of the current knowledge and evidence of the possibilities to tailor the dosage of selected SGAs using TDM, including the necessary pharmacokinetic parameters for personalised pharmacotherapy.

Association of clozapine and norclozapine levels with patient and therapy characteristics-focus on interaction with valproic acid

PURPOSE

The goal of the study was to examine clozapine (CLZ) and norclozapine (NCLZ) therapeutic drug monitoring (TDM) data and associated sources of pharmacokinetic variability, particularly the impact of valproic acid (VPA) use.

METHODS

This study included 126 patients with psychiatric disorders on mono- or co-therapy with CLZ. Patients' data during routine TDM were collected retrospectively from clinical records. The descriptive and statistical analysis was computed using IBM SPSS Statistics software (version 22, NY, USA). Multiple linear regression, based on the last observations, was used to assess correlation between demographic characteristics, life habits and co-therapy with dose-corrected serum levels (C/D) of CLZ and NCLZ, as well as CLZ/NCLZ.

RESULTS

A total of 295 CLZ concentrations were measured in 126 patients, with a mean of 275.5 ± 174.4 µg/L, while 124 NCLZ concentrations were determined in 74 patients, with a mean of 194.6 ± 149.8 µg/L. A statistically significant effect on ln-transformed CLZ C/D was confirmed for sex and smoking, whereas sex, smoking and VPA therapy were associated with ln-transformed NCLZ C/D. According to the final models, lower values of NCLZ C/D for about 45.9% can be expected in patients receiving VPA. Concomitant use of VPA was the only factor detected to contribute in CLZ/NCLZ variability.

CONCLUSION

The results of this study may help clinicians interpret TDM data and optimize CLZ dosing regimens, especially in patients concomitantly treated with VPA. Our results show that VPA primarily decreases NCLZ levels, while alteration of the parent drug is not statistically significant.

Association of smoking cigarettes, age, and sex with serum concentrations of olanzapine in patients with schizophrenia

Introduction

Olanzapine is an atypical antipsychotic drug which is effective in the treatment of schizophrenia. Cigarette smoking, age, and sex could be related to the pharmacokinetics and serum concentrations of olanzapine in patients with schizophrenia. The aim of the study was to examine whether there was a significant difference in the serum olanzapine concentrations with regard to the mentioned factors.

Materials and methods

A total of 58 outpatients with schizophrenia (37 smokers, 42 men, 35 older than 40 years) participated in the study. Blood was sampled in serum tubes just before taking the next dose of olanzapine. Olanzapine was extracted by liquid-liquid extraction and was measured by an in-house high-performance liquid chromatography method on Shimadzu Prominence HPLC System with diode array detector SPD-M20A (Shimadzu, Kyoto, Japan). The results were expressed as the ratio of concentration to the daily dose of olanzapine (C/D). Non-parametric statistical tests were used to analyse differences between variables.

Results

The median C/D of olanzapine (interquartile range) in smokers was 6.0 (3.4-10.2) nmol/L/mg and in non-smokers 10.1 (5.9-17.6) nmol/L/mg; P = 0.007. The median C/D of olanzapine in patients younger than 40 years was 5.6 (4.5-10.2) nmol/L/mg and in patients older than 40 years 8.4 (5.6-13.0) nmol/L/mg; P = 0.105. The median C/D of olanzapine in male patients was 6.6 (4.6-10.4) nmol/L/mg and in female patients 9.0 (5.9-15.3) nmol/L/mg; P = 0.064.

Conclusions

The serum olanzapine concentration was significantly lower in smoking than in non-smoking patients with schizophrenia. No significant difference was demonstrated with regard to age and sex.

Psychopharmacology of smoking cessation medications: focus on patients with mental health disorders

The adverse effects of smoking cessation in individuals with mental health disorders have been a point of concern, and progress in the development of treatment has been slow. The primary first-line treatments for smoking cessation are Nicotine Replacement Therapy, Bupropion, Varenicline, and behavioural support. Nortriptyline and Clonidine are second-line treatments used when the first-line treatments are not effective or are contraindicated. Smoking cessation medications have been shown to be effective in reducing nicotine cravings and withdrawal symptoms and promoting smoking cessation among patients living with mental disorders. However, these medications may have implications for patients' mental health and need to be monitored closely. The efficacy and side effects of these medications may vary depending on the patient's psychiatric condition, medication regimen, substance use, or medical comorbidities. The purpose of this review is to synthesise the pharmacokinetics, pharmacodynamics, therapeutic effects, adverse effects, and pharmacological interactions of first- and second-line smoking cessation drugs, with an emphasis on patients suffering from mental illnesses. Careful consideration of the risks and benefits of using smoking cessation medications is necessary, and treatment plans must be tailored to individual patients' needs. Monitoring symptoms and medication regimens is essential to ensure optimal treatment outcomes.

The potential role of por*28 and cyp1a2*f genetic variations and lifestyle factors on clozapine and n-desmethyl clozapine plasma levels in schizophrenia patients

BACKGROUND

Despite its advantages over other antipsychotics, for treatment-resistant schizophrenia, clinical use of Clozapine (CLZ) is challenging by its narrow therapeutic index and potentially life-threatening dose-related adverse effects.

RESEARCH DESIGN AND METHODS

As the potential role in CLZ metabolism is assigned to CYP1A2 enzyme and consequently Cytochrome P450 oxidoreductase (POR) their genetic variations might help to determine CLZ levels in schizophrenia patients. For this purpose, 112 schizophrenia patients receiving CLZ were included in the current study. Plasma CLZ and N-desmethylclozapine (DCLZ) levels were analyzed by using HPLC and genetic variations were identified with the PCR-RFLP method.

RESULTS

The patients' CYP1A2 and POR genotypes seemed to not affect plasma CLZ and DCLZ levels whereas in the subgroup analysis, POR × 28 genotype significantly influenced simple and adjusted plasma CLZ and DLCZ levels concerning smoking habit and caffeine consumption.

CONCLUSIONS

The findings of the present study highlight the importance of both genetic and non-genetic factors (smoking and caffeine consumption) for the individualization of the CLZ treatment. In addition to that, it suggests that the added utility of not only the CLZ metabolizing enzymes but also POR, which is crucial for proper CYP activity, to guide CLZ dosing might be useful for clinical decision-making.

Outcomes Among People With Schizophrenia Participating in General-Population Smoking Cessation Treatment: An Observational Study

OBJECTIVE

People with schizophrenia are much more likely than others to smoke tobacco, raising risks of disease and premature mortality. These individuals are also less likely to quit successfully after treatment, but the few existing clinical and observational studies have been limited by small sample sizes, and have generally considered specialized treatment approaches. In this analysis, we examine outcomes, service use, and potential explanatory variables in a large sample of people with schizophrenia treated in a general-population cessation program.

METHOD

Our sample comprised 3,011 people with schizophrenia and 77,790 controls receiving free nicotine replacement therapy through 400 clinics and health centres. We analysed self-reported 7-day abstinence or reduction at 6-month follow-up, as well as the number of visits attended and self-reported difficulties in quitting. We adjusted for demographic, socioeconomic, and health variables, and used multiple imputation to address missing data.

RESULTS

Abstinence was achieved by 16.2% (95% confidence interval [CI], 14.5% to 17.8%) of people with schizophrenia and 26.4% (95% CI, 26.0% to 26.7%) of others (absolute difference = 10.2%; 95% CI, 8.5% to 11.9%; P < 0.001). After adjustment, this difference was reduced to 7.3% (95% CI, 5.4% to 9.3%; P < 0.001). Reduction in use was reported by 11.8% (95% CI, 10.3% to 13.3%) and 12.5% (95% CI, 12.2% to 12.8%), respectively; this difference was nonsignificant after adjustment. People with schizophrenia attended more clinic visits (incidence rate ratio [IRR] = 1.15, 95% CI = 1.12% to 1.18%, P < 0.001) and reported more difficulties related to "being around other smokers" (odds ratio [OR] = 1.28; 95% CI, 1.11% to 1.47%; P = 0.001).

CONCLUSION

There is abundant demand for tobacco cessation treatment in this population. Outcomes were substantially poorer for people with schizophrenia, and this difference was not explained by covariates. Cessation remained much better than for unaided quit attempts, however, and engagement was high, demonstrating that people with schizophrenia benefit from nonspecialized pharmacological treatment programs.

Deep Learning Methods Applied to Drug Concentration Prediction of Olanzapine

Pharmacometrics and the utilization of population pharmacokinetics play an integral role in model-informed drug discovery and development (MIDD). Recently, there has been a growth in the application of deep learning approaches to aid in areas within MIDD. In this study, a deep learning model, LSTM-ANN, was developed to predict olanzapine drug concentrations from the CATIE study. A total of 1527 olanzapine drug concentrations from 523 individuals along with 11 patient-specific covariates were used in model development. The hyperparameters of the LSTM-ANN model were optimized through a Bayesian optimization algorithm. A population pharmacokinetic model using the NONMEM model was constructed as a reference to compare to the performance of the LSTM-ANN model. The RMSE of the LSTM-ANN model was 29.566 in the validation set, while the RMSE of the NONMEM model was 31.129. Permutation importance revealed that age, sex, and smoking were highly influential covariates in the LSTM-ANN model. The LSTM-ANN model showed potential in the application of drug concentration predictions as it was able to capture the relationships within a sparsely sampled pharmacokinetic dataset and perform comparably to the NONMEM model.

Smoking Habits and Attitudes toward Smoking in Patients with Severe Mental Illness in Residential Facilities in Insular Greece

Smoking may contribute to increased cardiovascular morbidity and mortality in patients with schizophrenia spectrum disorders. The objective of the present study is to explore the attitudes toward smoking in patients with severe mental illness in residential rehabilitation facilities in insular Greece. The patients (n = 103) were studied with the use of a questionnaire based on a semi-structured interview. Most of the participants (68.3%) were current regular smokers, had been smoking for 29 years and started smoking at an early age. The majority (64.8%) reported having tried to quit smoking in the past, and only half had been advised by a physician to quit. The patients agreed on the rules for smoking and believed that the staff should avoid smoking in the facility. The years of smoking were statistically significantly correlated to the educational level and the treatment with antidepressant medication. A statistical analysis showed that longer stay period in the facilities correlates with current smoking, an effort to quit and increased belief that smoking causes harm to health. Further research on the attitudes of patients in residential facilities toward smoking is needed, which could guide interventions for smoking cessation and should be assumed by all health professionals who are involved in the care of those patients.

Patients' and primary carers' views on clozapine treatment for schizophrenia: A cross-sectional study in Qatar

Subjective views of clozapine treatment among patients with schizophrenia in the Middle East and North African MENA Region have not previously been assessed. Globally, few studies have assessed the views of carers to clozapine treatment. We conducted a cross-sectional survey, using a clinician administered structured interview, of patients with schizophrenia/schizoaffective disorder prescribed clozapine in Qatar, and their primary carers. Participants were asked to rate clozapine against prior their antipsychotic treatment in terms of specific benefits and side effects. Forty-two patients and 33 carers participated in the study. Of the patients, two thirds were male, approximately half were Qatari and the mean age was 33.9 years. Patients and carers rated clozapine as superior to prior antipsychotic treatment on all 7 potential benefits inquired about. The greatest perceived benefit was improved mood. Patients rated clozapine as less likely to cause extrapyramidal side effects but more likely to cause 18 other potential side effects compared to prior antipsychotic treatment, with the greatest difference being for nocturnal salivation, increased appetite, and constipation. Nearly half of patients (48 %) and two thirds of carers (64 %) stated that they would have preferred to start clozapine earlier in their illness. Sixty percent of patients and 37 % of carers regarded the information that they had received from health professionals on clozapine as inadequate. Less than half of patients and approximately-two thirds of carers had adequate knowledge of haematological monitoring for clozapine. Generally, there were significantly positive correlation between patients and carers regarding the overall side effects of clozapine treatment. Likewise, improvement in hearing voices paranoid thoughts correlated with improved quality of life. In summary, the results show that patients and carers appreciate the benefits of clozapine despite its side effects being problematic. The results support clozapine being offered earlier in treatment and services providing more information on clozapine to patients and carers.

Smoking Addiction in Patients with Schizophrenia Spectrum Disorders and Its Perception and Intervention in Healthcare Personnel Assigned to Psycho-Rehabilitation Programs: A Qualitative Research

Patients with schizophrenia spectrum disorders have a higher prevalence and frequency of smoking rates when compared to the rest of the population; to this, it must be added that they develop a greater dependence and have some worse health consequences than the general population. This is qualitative research on the perception of smoking in healthcare professionals assigned to psycho-rehabilitation programs for patients with schizophrenia spectrum disorders. The point of view of health personnel (Psychologists, Psychiatrists, Pedagogists, and Nurses) about cigarette smoking in these patients was analyzed, focusing on their implications in disturbance and comparing them with e-cigarettes too. The methodology used to collect the data was a semi-structured interview with five questions. The research path was carried out in two assisted therapeutic communities that are clinics for the rehabilitation of serious mental illness in the period between November and July 2022. The results showed that the opinion of health professionals on smoking is very negative. Research has also shown that nearly all patients are smokers; however, their high grade of addiction is caused by periods of high stress due to various factors that lead patients to consume a greater number of cigarettes. Almost all respondents have a positive opinion of the e-cigarette, which was defined as an excellent substitute for traditional cigarettes.

Comorbidities and the right dose: antipsychotics

INTRODUCTION

The effects of antipsychotic drugs are dose-dependent, which is particularly true for their efficacy, each antipsychotic having a specific dose-response curve. This may justify individualizing doses for these agents.

AREAS COVERED

We review the pharmacokinetic profiles of seven oral antipsychotics: haloperidol, risperidone, olanzapine, clozapine, quetiapine, ziprasidone, and aripiprazole. Their main indications are psychotic and affective disorders. They are prescribed in a very large population which may have comorbidities. Hence, we analyze the impact of the latter on the pharmacokinetic profiles of these antipsychotics, focusing on renal and hepatic impairment. Reviews and clinical trials were discussed based on a systematic literature search (PubMed) ranging from 1995 to 2022.

EXPERT OPINION

Factors liable to impact antipsychotic dosage are numerous and their subsequent effects often hard to predict, due to multi-level interactions and compensatory phenomena. In clinical practice, physicians must be aware of these potential effects, but base their decisions on monitoring antipsychotic plasma levels.

Clozapine's multiple cellular mechanisms: What do we know after more than fifty years? A systematic review and critical assessment of translational mechanisms relevant for innovative strategies in treatment-resistant schizophrenia

Almost fifty years after its first introduction into clinical care, clozapine remains the only evidence-based pharmacological option for treatment-resistant schizophrenia (TRS), which affects approximately 30% of patients with schizophrenia. Despite the long-time experience with clozapine, the specific mechanism of action (MOA) responsible for its superior efficacy among antipsychotics is still elusive, both at the receptor and intracellular signaling level. This systematic review is aimed at critically assessing the role and specific relevance of clozapine's multimodal actions, dissecting those mechanisms that under a translational perspective could shed light on molecular targets worth to be considered for further innovative antipsychotic development. In vivo and in vitro preclinical findings, supported by innovative techniques and methods, together with pharmacogenomic and in vivo functional studies, point to multiple and possibly overlapping MOAs. To better explore this crucial issue, the specific affinity for 5-HT₂R, D1R, α_2c, and muscarinic receptors, the relatively low occupancy at dopamine D2R, the interaction with receptor dimers, as well as the potential confounder effects resulting in biased ligand action, and lastly, the role of the moiety responsible for lipophilic and alkaline features of clozapine are highlighted. Finally, the role of transcription and protein changes at the synaptic level, and the possibility that clozapine can directly impact synaptic architecture are addressed. Although clozapine's exact MOAs that contribute to its unique efficacy and some of its severe adverse effects have not been fully understood, relevant information can be gleaned from recent mechanistic understandings that may help design much needed additional therapeutic strategies for TRS.

Olanzapine/Samidorphan: A New Combination Treatment for Schizophrenia and Bipolar I Disorder Intended to Reduce Weight Gain

Olanzapine is a second-generation antipsychotic with established efficacy in several psychiatric disease states, but its use is limited because of weight gain and metabolic side effects. Samidorphan is a novel opioid antagonist that binds to mu-opioid, kappa-opioid, and delta-opioid receptors and is hypothesized to reduce cravings for high-calorie foods thus attenuating antipsychotic-induced weight gain. The combination product olanzapine/samidorphan was approved by the US Food and Drug Administration in June 2021 for the treatment of schizophrenia and bipolar I disorder; this article reviews the pharmacological properties of oral olanzapine/samidorphan and its clinical efficacy and tolerability with a focus on mitigation of olanzapine-induced weight gain in these patient populations. In clinical trials, the combination of olanzapine/samidorphan was associated with significantly less weight gain and smaller increases in waist circumference as compared with olanzapine monotherapy. Olanzapine/samidorphan demonstrated similar efficacy as olanzapine monotherapy and was well tolerated. Weight gain and metabolic side effects associated with olanzapine monotherapy can result in tolerability issues and potentially medication nonadherence. Olanzapine/samidorphan is an effective treatment for schizophrenia and bipolar I disorder with less weight gain than olanzapine monotherapy.

Clozapine Once-Daily Versus Divided Dosing Regimen: A Cross-sectional Study in Japan

OBJECTIVE

Clozapine is generally recommended to be prescribed in a divided dosing regimen based on its relatively short plasma half-life. However, there has been little evidence to support the superiority of divided dosing of clozapine over once-daily dosing. To our knowledge, there have been no studies examining differences in actual plasma concentrations or adverse effects between the 2 dosing strategies of clozapine. We aimed to compare actual plasma concentrations of clozapine between once-daily and divided dosing regimens, and to examine the relationships of these regimens with psychiatric symptoms and adverse effects of clozapine.

METHODS

We analyzed data from 108 participants of a previous study conducted in 2 hospitals in Japan. A population pharmacokinetic model was used to estimate the peak and trough plasma concentrations of clozapine based on actual plasma concentrations. We evaluated psychiatric symptoms with the Brief Evaluation of Psychosis Symptom Domains and adverse effects of clozapine with the Glasgow Antipsychotic Side-effects Scale for Clozapine.

RESULTS

The estimated peak and trough plasma concentrations of clozapine did not differ significantly between once-daily and divided dosing regimens. There were no significant differences in psychiatric symptoms except for depression/anxiety or subjective adverse effects of clozapine between the 2 dosing strategies.

CONCLUSIONS

Our findings tentatively support the feasibility and clinical utility of once-daily dosing of clozapine in clinical practice. Further studies are needed to replicate these findings and determine causality between dosing strategies and clinical outcomes.

Accuracy of self-reported adherence and therapeutic drug monitoring in a psychiatric emergency ward

The aims of the study were: (1) the evaluation of the agreement between therapeutic drug monitoring (TDM) and a self-assessment of adherence to psychopharmacological treatments; (2) the identification of predictors of TDM results.Adherence in patients admitted into a psychiatric emergency service (PES) for a relapse of a schizophrenia spectrum disorder (SSD) or a bipolar disorder (BD; DSM-5) was assessed both directly with TDM and indirectly with a self-reported measure (Medication Adherence Report Scale -MARS- 10 items). The agreement between TDM and MARS was evaluated. Fifty-seven patients with SSD and 76 people with BD participated in the study. TDM was in range in about 50% of the global sample. No evidence of an association between MARS total scores and TDM results was found. Sensitivity, specificity, positive and negative predictive values of almost all MARS total scores were near to 50%. Smoking was strongly associated with a reduction of TDM results within the reference range. In the BD group, female sex was a predictor of TDM in range. In this clinical setting, self-assessment of adherence is neither reliable nor predictive. Furthermore, smoking is a strong predictor of poor adherence to psychopharmacological therapy.

Clinical and genetic influencing factors on clozapine pharmacokinetics in Tunisian schizophrenic patients

Clozapine (Clz) is an atypical antipsychotic, which its pharmacokinetics can be influenced by several factors. The CYP1A2 and CYP2C19, major enzymes implicated in Clz metabolism, present an interethnic variation on their activity caused by single nucleotide polymorphisms (SNPs). The present study investigated the influence of genetic and nongenetic factors on Clz pharmacokinetics in a southern Mediterranean population. We included adult Tunisian schizophrenic patients having received Clz and undergone a therapeutic drug monitoring (TDM) of Clz by morning C0 monitoring. The genomic DNA was extracted using a salting-out procedure. CYP1A2*1F (rs762551;-163C>A), CYP1A2*1C (rs2069514;-3860 G>A) and CYP 2C19*2 (rs4244285; 681G>A) was analyzed using PCR-RFLP. Fifty-one patients were enrolled in the study. The mutant allele (CYP1A2*1F) was the most frequently detected (58.8%). For CYP1A2*1F, Clz dose-normalized (C0/D ratio) was as high as 1.28 ± 0.37 in CC versus 0.67 ± 0.32 ng mL^-1 per mg day^-1 in AA group (p < 0.001). The influence of genetic (CYP1A2*1F, CYP1A2*1C and CYP2C19*2) and nongenetic parameters (age, weight, gender, tobacco, coffee, and alcohol consumption) on the variation of the Clz C0/D ratio was investigated. Only the CYP1A2*1 F polymorphism correlates significantly with the Clz C0/D variation and could explain 24% of its variability. Our data support a critical role of the CYP1A2 -163C>A on the variation of Clz exposure in Tunisian schizophrenic patients. Considering its narrow therapeutic range, CYP1A2 genotyping combined with TDM of Clz may improve efficacy and safety of this drug. Further studies are needed to investigate this issue.

Head circumference in infants with nonopiate-induced neonatal abstinence syndrome

BACKGROUND

No relationship has been reported between nonopiate neonatal abstinence syndrome (NAS) and anthropometric indices, including head circumference (HC). The purpose of this study was to determine the relationship between maternal nonopioid drug use and HC at birth in neonates with NAS.

METHODS

This retrospective observational study included neonates born between January 1, 2010 and March 31, 2019, whose mothers had been taking antipsychotic, antidepressant, sedative, or anticonvulsant medications. The outcome measures were HCs of NAS infants and controls.

RESULTS

Of 159 infants, 33 (21%) were diagnosed with NAS. There was no maternal opioid use among mothers during pregnancy. The HCs in the NAS group were significantly smaller than those in the control group. The median z-scores for HC at birth were -0.20 and 0.29 in the NAS group and the control group, respectively (P = .011). The median HCs at birth were 33.0 and 33.5 cm in the NAS group and the control group, respectively. Multivariate analysis revealed that maternal antipsychotic drug use and selective serotonin reuptake inhibitors were independently associated with NAS (P < .001 and P = .004, respectively). Notably, benzodiazepine use and smoking were not independent risk factors.

CONCLUSIONS

The results suggest an association between maternal antipsychotic drug use and NAS, which was further associated with decreased HC. Careful monitoring of maternal drug use should be considered to improve fetal outcomes.

Factors associated with fluoxetine and norfluoxetine plasma concentrations and clinical response in Mexican patients with mental disorders

Over the last few years, fluoxetine has been one of the most prescribed medications for the treatment of diverse psychiatric conditions in Mexico. Fluoxetine therapeutic effect is consequence of the joint action of the parent drug and its active metabolite, norfluoxetine. However, the clinical efficacy of fluoxetine, can be affected due to diverse factors, such as drug-drug interactions and the large interindividual variability in the pharmacokinetics of this drug. The aim of this study was to determine the factors associated with variability in plasma concentrations of fluoxetine and norfluoxetine and its association with the therapeutic response. Fluoxetine and norfluoxetine plasma concentrations were quantified by liquid chromatography in 81 Mexican patients with mental disorders; 25% of the patients had no medication adherence and 40% were below the reference range of fluoxetine plus norfluoxetine plasma concentrations. The results showed that concentrations can be affected by fluoxetine metabolism caused by CYP2D6 phenotype and the concomitant administration of olanzapine. Furthermore, CYP3A5 and CYP2C19 phenotype were associated with lower anxiety and depression control during treatment with fluoxetine. This study can be a starting point to elucidate the causes of fluoxetine variable response in Mexican patients with mental disorders, as well as to detect and support medication adherence.

Efficacy and safety of clozapine in psychotic disorders-a systematic quantitative meta-review

A recent increase in the literature regarding the evidence base for clozapine has made it increasingly difficult for clinicians to judge "best evidence" for clozapine use. As such, we aimed at elucidating the state-of-the-art for clozapine with regard to efficacy, effectiveness, tolerability, and management of clozapine and clozapine-related adverse events in neuropsychiatric disorders. We conducted a systematic PRISMA-conforming quantitative meta-review of available meta-analytic evidence regarding clozapine use. Primary outcome effect sizes were extracted and transformed into relative risk ratios (RR) and standardized mean differences (SMD). The methodological quality of meta-analyses was assessed using the AMSTAR-2 checklist. Of the 112 meta-analyses included in our review, 61 (54.5%) had an overall high methodological quality according to AMSTAR-2. Clozapine appears to have superior effects on positive, negative, and overall symptoms and relapse rates in schizophrenia (treatment-resistant and non-treatment-resistant subpopulations) compared to first-generation antipsychotics (FGAs) and to pooled FGAs/second-generation antipsychotics (SGAs) in treatment-resistant schizophrenia (TRS). Despite an unfavorable metabolic and hematological adverse-event profile compared to other antipsychotics, hospitalization, mortality and all-cause discontinuation (ACD) rates of clozapine surprisingly show a pattern of superiority. Our meta-review outlines the superior overall efficacy of clozapine compared to FGAs and most other SGAs in schizophrenia and suggests beneficial efficacy outcomes in bipolar disorder and Parkinson's disease psychosis (PDP). More clinical studies and subsequent meta-analyses are needed beyond the application of clozapine in schizophrenia-spectrum disorders and future studies should be directed into multidimensional clozapine side-effect management to foster evidence and to inform future guidelines.

Investigating Predictors of Clozapine Response in Adolescents with Schizophrenia and Schizoaffective Disorder

Objectives: We aimed to determine the clinical predictors of clozapine response in patients with early-onset schizophrenia (EOS)/schizoaffective disorder and the effect of substance use disorder (SUD) on treatment outcomes. Methods: Medical records of patients with treatment-resistant EOS receiving clozapine were identified for data analysis dated between January 2015 and April 2020. Patients on clozapine were followed in an inpatient unit of a tertiary care mental health hospital. Using the Positive and Negative Symptom Scale (PANSS), ≥30% reduction was defined as the response criteria after clozapine treatment. Results: Of 50 subjects (age: 16.3 ± 1.3 years, 36.0% female), 22 subjects (44.0%) met the defined response criteria. Clozapine responder (CLZ-R) and clozapine nonresponder (CLZ-NR) groups were similar regarding age at illness onset, sex, and duration of untreated psychosis. The CLZ-R group had higher baseline positive PANSS scores (24.8 ± 8.1 vs. 17.1 ± 6.6, p = 0.001, d = 1.0) and total PANSS scores (94.8 ± 17.2 vs. 80.1 ± 19.8, p = 0.008, d = 0.8) compared with the CLZ-NR counterparts. The duration of hospital stay was longer in the CLZ-NR group (122.3 ± 48.2 vs. 87.3 ± 36.2 days, p = 0.007). Among 32 male patients, the presence of SUD (n = 9, 28.1%) was associated with a less reduction in total PANSS scores (F = 7.5, p = 0.010) and higher levels of positive symptoms at the end of the treatment (12.8 ± 4.1 vs. 18.8 ± 7.4, p = 0.006, d = 1.0). Synthetic cannabinoids were the most common substance type used among males with treatment-refractory EOS (25.0%). Conclusions: Our results did not support the role of sociodemographic variables in clozapine response. Positive symptoms and SUD yielded a prognostic value in patients receiving clozapine.

Therapeutic drug monitoring of clozapine in adults with schizophrenia: a review of challenges and strategies

INTRODUCTION

Clozapine (CLZ) is the superior drug in treatment of schizophrenia. Serum concentration of CLZ is associated with clinical response and dose-dependents side effects, where generalized tonic-clonic seizures are most critical. Thus, therapeutic drug monitoring (TDM) of CLZ may guide individual dosing to reach target exposure and prevent dose-dependent side effects. However, current TDM methods are not capable of predicting the risk of agranulocytosis, which is a dose-independent side effect restricting use of CLZ to treatment-resistant schizophrenia (TRS).

AREAS COVERED

The article provides an overview of clinical, pharmacological, and toxicological aspects of CLZ, and the role of TDM as a tool for dose titration and follow-up in patients with TRS. Main focus is on current challenges and strategies in CLZ TDM, including future perspectives on potential identification/analysis of CLZ metabolite biomarkers reflecting the risk of granulocyte toxicity.

EXPERT OPINION

The association between CLZ serum concentration, clinical response and risk of seizures is indisputable. TDM should therefore always guide CLZ dose titration. Development of advanced TDM methods, including biomarkers predicting the risk of granulocyte toxicity might extend TDM to be a tool for deciding which patients that can be treated safely with CLZ, potentially increasing its utility beyond TRS.

Genetic Variations Associated with Long-Term Treatment Response in Bipolar Depression

Several pharmacogenetic-based decision support tools for psychoactive medication selection are available. However, the scientific evidence of the gene-drug pairs analyzed is mainly based on pharmacogenetic studies in patients with major depression or schizophrenia, and their clinical utility is mostly assessed in major depression. This study aimed at evaluating the impact of individual genes, with pharmacogenetic relevance in other psychiatric conditions, in the response to treatment in bipolar depression. Seventy-six patients diagnosed with bipolar disorder and an index major depressive episode were included in an observational retrospective study. Sociodemographic and clinical data were collected, and all patients were genotyped using a commercial multigene pharmacogenomic-based tool (Neuropharmagen^®, AB-Biotics S.A., Barcelona, Spain). Multiple linear regression was used to identify pharmacogenetic and clinical predictors of efficacy and tolerability of medications. The pharmacogenetic variables response to serotonin-norepinephrine reuptake inhibitors (SNRIs) (ABCB1) and reduced metabolism of quetiapine (CYP3A4) predicted patient response to these medications, respectively. ABCB1 was also linked to the tolerability of SNRIs. An mTOR-related multigenic predictor was also associated with a lower number of adverse effects when including switch and autolytical ideation. Our results suggest that the predictors identified could be useful to guide the pharmacological treatment in bipolar disorder. Additional clinical studies are necessary to confirm these findings.

What to Do About Missed Doses? A Retrospective Study of Olanzapine in the Elderly

Background

Schizophrenia is characterized by a high disease burden. Olanzapine is a common drug used in antipsychotic medication. Little is known about the population pharmacokinetics of olanzapine in elderly patients. Missed doses are a common and unavoidable issue during the treatment of psychiatric diseases, especially in elderly patients. This study aimed to identify what an elderly person should do if doses are inadvertently missed.

Methods

Data were collected from 140 elderly psychiatric patients (aged ≥65 years) who received olanzapine therapy. Olanzapine concentrations were determined by high pressure liquid chromatographic tandem mass spectrometry (HPLC-MS/MS) and a population-based approach was used to quantify the characteristics of elderly patients. A non-linear mixed-effects model was used for data analysis. Simulations based on the final model were applied to predict situations involving a single missed dose or three consecutive missed doses under several remedial regimens.

Results

A total of 474 samples from 140 elderly patients were included in the therapeutic drug monitoring (TDM) data analysis. A one-compartment model, with no significant covariates, was developed to describe the population pharmacokinetics of olanzapine in elderly patients. The population predicted systematic clearance (CL/F) and volumes of distribution (V/F) were 18 L/h and 785 L, respectively. The simulation demonstrated that in a missed dose situation, elderly patients should take the regular dose immediately; the refill dose used at the second remedial time point depends on the length of the time delay.

Conclusion

Here, we used a simulation to provide a remedial regimen for missed doses of olanzapine in the elderly population. Our simulation can provide valuable suggestions for individualized therapy in elderly patients.

Genetic Polymorphisms Associated With the Pharmacokinetics, Pharmacodynamics and Adverse Effects of Olanzapine, Aripiprazole and Risperidone

Olanzapine, aripiprazole and risperidone are atypical antipsychotics or neuroleptics widely used for schizophrenia treatment. They induce various adverse drug reactions depending on their mechanisms of action: metabolic effects, such as weight gain and alterations of glucose and lipid metabolism; hyperprolactinemia and extrapyramidal effects, such as tremor, akathisia, dystonia, anxiety and distress. In this review, we listed polymorphisms associated with individual response variability to olanzapine, aripiprazole and risperidone. Olanzapine is mainly metabolized by cytochrome P450 enzymes, CYP1A2 and CYP2D6, whereas aripiprazole and risperidone metabolism is mainly mediated by CYP2D6 and CYP3A4. Polymorphisms in these genes and other enzymes and transporters, such as enzymes from the uridine 5'-diphospho-glucuronosyltransferase (UGT) family and ATP-binding cassette sub-family B member 1 (ABCB1), are associated to differences in pharmacokinetics. The three antipsychotics act on dopamine and serotonin receptors, among others, and several studies found associations between polymorphisms in these genes and variations in the incidence of adverse effects and in the response to the drug. Since olanzapine is metabolized by CYP1A2, a lower starting dose should be considered in patients treated with fluvoxamine or other CYP1A2 inhibitors. Regarding aripiprazole, a reduced dose should be administered in CYP2D6 poor metabolizers (PMs). Additionally, a reduction to a quarter of the normal dose is recommended if the patient is treated with concomitant CYP3A4 inhibitors. Risperidone dosage should be reduced for CYP2D6 PMs and titrated for CYPD6 ultrarapid metabolizers (UMs). Moreover, risperidone dose should be evaluated when a CYP2D6, CYP3A4 or ABCB1 inhibitor is administered concomitantly.

Dysregulated inflammation may predispose patients with serious mental illnesses to severe COVID‑19 (Review)

Genetic and nongenetic factors associated with an increased inflammatory response may mediate a link between severe coronavirus disease 2019 (COVID‑19) and serious mental illness (SMI). However, systematic assessment of inflammatory response‑related factors associated with SMI that could influence COVID‑19 outcomes is lacking. In the present review, dietary patterns, smoking and the use of psychotropic medications are discussed as potential extrinsic risk factors and angiotensin‑converting enzyme (ACE) insertion/deletion (I/D) gene polymorphisms are considered as potential intrinsic risk factors. A genetics‑based prediction model for SMI using ACE‑I/D genotyping is also proposed for use in patients experiencing severe COVID‑19. Furthermore, the literature suggests that ACE inhibitors may have protective effects against SMI or severe COVID‑19, which is often linked to hypertension and other cardiovascular comorbidities. For this reason, we hypothesize that using these medications to treat patients with severe COVID‑19 might yield improved outcomes, including in the context of SMI associated with COVID‑19.

Therapeutic Drug Monitoring of Second- and Third-Generation Antipsychotic Drugs-Influence of Smoking Behavior and Inflammation on Pharmacokinetics

Both inflammation and smoking can influence a drug’s pharmacokinetic properties, i.e., its liberation, absorption, distribution, metabolism, and elimination. Depending on, e.g., pharmacogenetics, these changes may alter treatment response or cause serious adverse drug reactions and are thus of clinical relevance. Antipsychotic drugs, used in the treatment of psychosis and schizophrenia, should be closely monitored due to multiple factors (e.g., the narrow therapeutic window of certain psychotropic drugs, the chronicity of most mental illnesses, and the common occurrence of polypharmacotherapy in psychiatry). Therapeutic drug monitoring (TDM) aids with drug titration by enabling the quantification of patients’ drug levels. Recommendations on the use of TDM during treatment with psychotropic drugs are presented in the Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology; however, data on antipsychotic drug levels during inflammation or after changes in smoking behavior—both clinically relevant in psychiatry—that can aid clinical decision making are sparse. The following narrative review provides an overview of relevant literature regarding TDM in psychiatry, particularly in the context of second- and third-generation antipsychotic drugs, inflammation, and smoking behavior. It aims to spread awareness regarding TDM (most pronouncedly of clozapine and olanzapine) as a tool to optimize drug safety and provide patient-tailored treatment.

Therapeutic Drug Monitoring of Second- and Third-Generation Antipsychotic Drugs—Influence of Smoking Behavior and Inflammation on Pharmacokinetics

Both inflammation and smoking can influence a drug’s pharmacokinetic properties, i.e., its liberation, absorption, distribution, metabolism, and elimination. Depending on, e.g., pharmacogenetics, these changes may alter treatment response or cause serious adverse drug reactions and are thus of clinical relevance. Antipsychotic drugs, used in the treatment of psychosis and schizophrenia, should be closely monitored due to multiple factors (e.g., the narrow therapeutic window of certain psychotropic drugs, the chronicity of most mental illnesses, and the common occurrence of polypharmacotherapy in psychiatry). Therapeutic drug monitoring (TDM) aids with drug titration by enabling the quantification of patients’ drug levels. Recommendations on the use of TDM during treatment with psychotropic drugs are presented in the Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology; however, data on antipsychotic drug levels during inflammation or after changes in smoking behavior—both clinically relevant in psychiatry—that can aid clinical decision making are sparse. The following narrative review provides an overview of relevant literature regarding TDM in psychiatry, particularly in the context of second- and third-generation antipsychotic drugs, inflammation, and smoking behavior. It aims to spread awareness regarding TDM (most pronouncedly of clozapine and olanzapine) as a tool to optimize drug safety and provide patient-tailored treatment.

Therapeutic Drug Monitoring of Second- and Third-Generation Antipsychotic Drugs-Influence of Smoking Behavior and Inflammation on Pharmacokinetics

Both inflammation and smoking can influence a drug's pharmacokinetic properties, i.e., its liberation, absorption, distribution, metabolism, and elimination. Depending on, e.g., pharmacogenetics, these changes may alter treatment response or cause serious adverse drug reactions and are thus of clinical relevance. Antipsychotic drugs, used in the treatment of psychosis and schizophrenia, should be closely monitored due to multiple factors (e.g., the narrow therapeutic window of certain psychotropic drugs, the chronicity of most mental illnesses, and the common occurrence of polypharmacotherapy in psychiatry). Therapeutic drug monitoring (TDM) aids with drug titration by enabling the quantification of patients' drug levels. Recommendations on the use of TDM during treatment with psychotropic drugs are presented in the Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology; however, data on antipsychotic drug levels during inflammation or after changes in smoking behavior-both clinically relevant in psychiatry-that can aid clinical decision making are sparse. The following narrative review provides an overview of relevant literature regarding TDM in psychiatry, particularly in the context of second- and third-generation antipsychotic drugs, inflammation, and smoking behavior. It aims to spread awareness regarding TDM (most pronouncedly of clozapine and olanzapine) as a tool to optimize drug safety and provide patient-tailored treatment.

Non-pharmacological interventions for smoking in persons with schizophrenia spectrum disorders - A systematic review

INTRODUCTION

The rates and intensity of tobacco use are higher in persons with schizophrenia spectrum disorders (PwS) compared to the general population, contributing to increased morbidity and mortality. We aimed to systematically review randomised control trials (RCTs) that used non-pharmacological interventions to reduce or cease tobacco use in PwS.

METHODS

We searched PubMed, EBSCO, ProQuest and PsycINFO for RCTs, published between January 2004 and December 2019, which included adult PwS. Studies providing self-reported or biochemically measured reduction of tobacco use and cessation after a minimum follow-up period of 6 months were included. We used the Cochrane Risk of Bias (ROB) tool for assessing the quality of selected studies.

RESULTS

Of the six included trials, two compared non-pharmacological interventions alone while four compared combinations with pharmacological interventions with routine care. The non-pharmacological interventions varied widely. Continuous abstinence and seven days point-prevalence abstinence (7 PPA) were reported in 2 and 4 studies respectively, with one study assessing both. All six trials measured reduction in the number of cigarettes smoked, but only two trials reported significant reductions in intervention groups. No worsening of psychiatric symptoms was reported.

CONCLUSIONS

Two trials were rated as "low risk", and 4 trials as "some concerns" on the ROB tool. Heterogeneity among trials precluded meta-analysis. Abstinence was significantly higher among groups who were given combination interventions, and intervention groups in studies showed significantly greater or a trend towards reduction in the number of cigarettes smoked than controls. No specific method of non-pharmacological management was conclusively favoured.

IMPLICATIONS

Reduction in cigarettes smoked seemed to significantly favour or show non-significant trends favouring intervention groups over controls, while abstinence was significantly higher among groups in studies that used specific combination interventions. Combinations of pharmacological and non-pharmacological treatment were better than non-pharmacological interventions used in isolation, for facilitating abstinence and reduction in cigarettes smoked. Specific interventions such as home visits and contingent reinforcement merit further study. Trials included in this study were conducted in high-income and upper-middle-income countries. Thus, the application of these interventions to low and middle-income countries (LAMICs) needs to be further studied.

Retrospective Review of Clozapine Use in Children and Adolescents

OBJECTIVE

Literature describing use of clozapine by children and adolescents is limited. The primary study objective was to assess the patterns of clozapine use in an inpatient child and adolescent population.

METHODS

A retrospective review of child and adolescent inpatients receiving clozapine at a Canadian children's hospital from January 2000 through December 2014 was conducted. Interdisciplinary comprehensive data collection was conducted by experienced clinicians. Baseline population characteristics and psychiatric illness risk factors were captured. Illness symptoms and severity were assessed retrospectively using validated measures including the Brief Psychiatric Rating Scale (BPRS), Children's Global Assessment Scale (CGAS) and Clinical Global Impressions (CGI) scales. Estimated clozapine dosing requirements for each patient to achieve a serum level associated with response was calculated. Clozapine-related adverse events were captured.

RESULTS

Twenty-eight inpatients (64% female) receiving clozapine during the study period were identified. Mean age at clozapine initiation was 15.8 years. Twenty-three patients (82%) were taking clozapine at discharge, and of these, 22 patients (96%) experienced at least minimal improvement in BPRS and CGAS scores. Patients took a mean of 33.1 days from clozapine start to reach their maximum clozapine dosage, a mean maximum of 57% of their estimated clozapine dose requirement. Mean length of stay following clozapine initiation was 60.7 days. We observed a high rate of benign hematological adverse events, but no episodes of severe neutropenia. The majority of patients were of ethnicity associated with high risk for metabolic adverse events.

CONCLUSION

Most hospitalized, treatment-refractory children requiring clozapine clinically improve despite experiencing high, but largely manageable, adverse event rates.

Clinical, Biochemical and Genetic Variables Associated With Metabolic Syndrome in Patients With Schizophrenia Spectrum Disorders Using Second-Generation Antipsychotics: A Systematic Review

Background: Individuals with severe mental illness experience increased morbidity and mortality compared to the general population. Adverse effects of antipsychotics, including weight gain, may contribute to the development of metabolic syndrome (MetS), which is associated with increased risks of all-cause and cardiovascular disease mortality. We aim to provide a comprehensive overview of clinical, biochemical and genetic factors associated with MetS among patients with schizophrenia spectrum disorders using second-generation antipsychotics (SGA). Methods: A literature search was performed in Pubmed and Embase to identify all cohort studies, cross-sectional studies and clinical trials investigating associations with MetS in patients with schizophrenia spectrum disorders using SGAs. We extracted and enumerated clinical, biochemical and genetic factors reported to be associated with MetS. We defined factors associated with MetS as factors being reported as associated with MetS in two or more studies. Results: 58 studies were included in this review (n = 12,123). In total, 62 factors were found to be associated with increased risk of MetS. Thirty one out of 58 studies investigated factors that were reported as associated with MetS in two or more studies. With regard to clinical factors, we found gender, higher age, concomitant use of mood stabilizers, higher baseline and current BMI, earlier SGA exposure, higher dose, longer duration of treatment, psychosis and tobacco smoking to be significantly associated with MetS. Furthermore, the biochemical factors hypo-adiponectinemia, elevated levels of C-reactive protein (CRP) and higher white blood cell (WBC) count were identified as factors associated with MetS. Among pharmacogenetic factors, the rs1414334 C-allele of the HTR2C-gene was associated with MetS in patients using SGA. Conclusion: In this systematic review investigating clinical, biochemical and genetic factors associated with MetS in patients using SGAs we found that higher age, higher baseline BMI, higher current BMI and male as well as female gender were positively associated with MetS across all antipsychotics. This study may set the stage for the application of clinical, biochemical and genetic factors to predict the risk of developing MetS in patients using SGAs. Future research is needed to determine which patients using SGAs are at risk to develop MetS in clinical practice.

Cigarette Smoking and Schizophrenia: Etiology, Clinical, Pharmacological, and Treatment Implications

Recent data suggests that the prevalence of smoking in schizophrenia remains high. While reports suggest that smoking increases the risk of developing schizophrenia, the potential causative role of smoking in this relationship needs further investigation. Smokers with schizophrenia are more likely to have more intense positive symptoms and lower cognitive function, but diminished intensity of extrapyramidal side effects than nonsmoking patients with schizophrenia. They were also more likely to exhibit aggressive behaviour compared to nonsmokers, which could suggest higher levels of baseline aggression. The significant cost associated with regular tobacco expenditure can detract from investment in key domains. Large-scale trials have shown that pharmacotherapy for smoking cessation is effective and does not worsen the risk of developing neuropsychiatric symptoms compared to placebo. Electronic cigarette use among schizophrenia patients is high, and there is emerging evidence supportive of its efficacy. Future improvements include large-scale trials assessing the utility, efficacy, and safety of electronic cigarettes in schizophrenia patients.

Absolute and Dose-Adjusted Serum Concentrations of Clozapine in Patients Switching vs. Maintaining Treatment: An Observational Study of 1979 Patients

BACKGROUND

Clozapine is an effective drug for the management of schizophrenia that has not responded to other agents, but some patients experience insufficient or adverse effects and discontinue treatment.

OBJECTIVE

We investigated a potential association between clozapine serum concentrations and switching to other antipsychotics in a large real-world patient population from a therapeutic drug monitoring service.

METHODS

Absolute and dose-adjusted serum concentrations (concentration-to-dose ratios [C/D ratios]) of clozapine during dosing between 100 and 1000 mg/day were measured in 1979 Norwegian patients during the period 2005-2019. These variables were compared in patients switching to other antipsychotic drugs versus maintaining clozapine treatment using linear mixed models. Smoking habits were known for 49% of the patients. To prevent potential nonadherence affecting clozapine switching, only patients with serum concentrations above 50% of the lower reference range were included.

RESULTS

In total, 190 patients (9.6%) switched from clozapine to another antipsychotic drug during the study period, whereas the remaining patients were not detected as switchers and were interpreted as maintaining treatment. Patients switching treatment had 23.5% lower absolute concentrations (954 vs. 1245 nmol/L; p < 0.001) and 15.7% lower daily doses (305 vs. 362 mg/day; p < 0.001) of clozapine than did nonswitchers, making the clozapine C/D ratio 9.7% lower in switchers than in nonswitchers after correcting for smoking habits (2.80 vs. 3.10 nmol/L/mg/day; p = 0.032).

CONCLUSIONS

The present study suggests that decreased absolute and dose-adjusted serum concentrations of clozapine were associated with clozapine discontinuation. The significantly reduced clozapine concentrations regardless of prescribed dose in switchers versus nonswitchers may indicate a pharmacokinetic mechanism underlying the risk of clozapine discontinuation.

How Can Drug Metabolism and Transporter Genetics Inform Psychotropic Prescribing?

Many genetic variants in drug metabolizing enzymes and transporters have been shown to be relevant for treating psychiatric disorders. Associations are strong enough to feature on drug labels and for prescribing guidelines based on such data. A range of commercial tests are available; however, there is variability in included genetic variants, methodology, and interpretation. We herein provide relevant background for understanding clinical associations with specific variants, other factors that are relevant to consider when interpreting such data (such as age, gender, drug-drug interactions), and summarize the data relevant to clinical utility of pharmacogenetic testing in psychiatry and the available prescribing guidelines. We also highlight areas for future research focus in this field.

Impact of smoking behavior on clozapine blood levels - a systematic review and meta-analysis

OBJECTIVE

Tobacco smoking significantly impacts clozapine blood levels and has substantial implications on individual efficacy and safety outcomes. By investigating differences in clozapine blood levels in smoking and non-smoking patients on clozapine, we aim to provide guidance for clinicians how to adjust clozapine levels for patients on clozapine who change their smoking habits.

METHODS

We conducted a meta-analysis on clozapine blood levels, norclozapine levels, norclozapine/clozapine ratios, and concentration to dose (C/D) ratios in smokers and non-smokers on clozapine. Data were meta-analyzed using a random-effects model with sensitivity analyses on dose, ethnic origin, and study quality.

RESULTS

Data from 23 studies were included in this meta-analysis with 21 investigating differences between clozapine blood levels of smokers and non-smokers. In total, data from 7125 samples were included for the primary outcome (clozapine blood levels in ng/ml) in this meta-analysis. A meta-analysis of all between-subject studies (N = 16) found that clozapine blood levels were significantly lower in smokers compared with non-smokers (Standard Mean Difference (SMD) -0.39, 95% confidence interval (CI) -0.55 to -0.22, P < 0.001, I²  = 80%). With regard to the secondary outcome, C/D ratios (N = 16 studies) were significantly lower in the smoker group (n = 645) compared with the non-smoker group (n = 813; SMD -0.70, 95%CI -0.84 to -0.56, P < 0.00001, I²  = 17%).

CONCLUSION

Smoking behavior and any change in smoking behavior is associated with a substantial effect on clozapine blood levels. Reductions of clozapine dose of 30% are recommended when a patient on clozapine stops smoking. Reductions should be informed by clozapine steady-state trough levels and a close clinical risk-benefit evaluation.

Effects of Smoking Status on Remission and Metabolic and Cognitive Outcomes in Schizophrenia Patients Treated with Clozapine

BACKGROUND

Even though clozapine is the recommended last-resort antipsychotic, many patients fail to respond and show treatment-refractory psychotic symptoms. Smoking has been suggested as a possible risk factor for poor clozapine response, hampering remission and negatively impacting somatic outcomes.

METHODS

Our aim was to test whether smoking status is associated with remission rates and other symptomatic and somatic outcomes. We therefore assessed remission rates according to The Remission in Schizophrenia Working Group (RSWG) criteria, and metabolic and cognitive outcomes among patients with schizophrenia-spectrum disorders treated with clozapine for at least 6 months. For analyses, we grouped our cohort into 3 groups according to clozapine treatment duration (6 months, 2 years, 5 years).

RESULTS

One hundred five patients were included in our analyses and grouped according to their clozapine treatment duration. In the 6-months analyses, patients who smoked were significantly more likely to be younger of age (p=0.002) despite on average shorter duration of clozapine treatment (p=0.041) and significantly more likely to be treated with mood-stabilizing co-medication (p=0.030) compared to nonsmokers. Remission rates (p=0.490), as well as a set of metabolic and cognitive variables did not differ between the 2 groups. A related pattern could be observed for the 2- and 5-years analyses.

CONCLUSIONS

Smoking behavior among clozapine-treated schizophrenia patients might delineate a cohort with an earlier onset of the disease. Nevertheless, most findings comparing disease-specific and clinical outcomes among smokers and nonsmokers were negative. Further research is needed to identify strategies to overcome insufficient remission rates in this patient group.

Educational needs and psychoeducation interventions in clozapine users: a narrative review

OBJECTIVE

Increasing users' knowledge about the expected benefits and risks of clozapine may contribute to the initiation and maintenance of clozapine in persons with treatment-resistant schizophrenia (TRS). The objective was to identify the educational needs of clozapine users and the interventions aimed at addressing these needs.

METHOD

We systematically searched multiple electronic databases for articles: (i) exploring educational needs of clozapine users and of their relatives; and (ii) reporting educational interventions aimed at addressing these needs. Data were synthesized narratively.

RESULTS

A total of 30 articles published from 1990 to 2019 in 8 countries fulfilled our inclusion criteria. As most studies on educational needs (n = 18) were carried out in persons already taking clozapine, educational needs of TRS patients who were candidates for clozapine treatment are not well documented. Users' level of knowledge about clozapine was often poor, especially about adverse effects or interactions with other substances, with a poor retention of information delivered at treatment initiation. Among 12 studies reporting educational interventions in clozapine users, five provided quantitative outcomes. Their findings suggest that structured educational programmes may contribute to promote clozapine initiation and to improve users' knowledge about this drug.

CONCLUSION

The literature is sparse on structured educational interventions about clozapine, and only one randomized controlled trial was identified. A promising strategy emerging from this review may be staging educational interventions according to the evolving needs of persons with TRS before clozapine use, at initiation and during maintenance treatment.

Tobacco smoking, related harm and motivation to quit smoking in people with schizophrenia spectrum disorders

This narrative review focuses on the topic of tobacco smoking amongst people with schizophrenia spectrum disorders. We searched PubMed, PsycInfo and Scopus databases for schizophrenia spectrum disorders and smoking and included articles about the epidemiology of tobacco smoking in people with schizophrenia spectrum disorders, examining the relationship between smoking and mental health. This narrative review describes that a higher prevalence, frequency and impact of both high nicotine dependence and its harmful effects in patients with schizophrenia spectrum disorders compared with those in the general population. Despite several existent theories, the reasons for high smoking rates, the high dependence on nicotine and severity of nicotine withdrawal symptoms are not fully understood. The main aim of this paper is to inform mental health personnel and particularly clinical and health psychologists about the impact and role of tobacco smoking for smokers with schizophrenia spectrum disorders.

[Informations on psychotropics and their adaptations for patients suffering from mental disorders in France during the SARS-CoV-2 epidemic]

The 2019-20 coronavirus pandemic (SARS-CoV-2; severe acute respiratory syndrome coronavirus 2) has dramatic consequences on populations in terms of morbidity and mortality and in social terms, the general confinement of almost half of the world's population being a situation unprecedented in history, which is difficult today to measure the impact at the individual and collective levels. More specifically, it affects people with various risk factors, which are more frequent in patients suffering from psychiatric disorders. Psychiatrists need to know: (i) how to identify, the risks associated with the prescription of psychotropic drugs and which can prove to be counterproductive in their association with COVID-19 (coronavirus disease 2019), (ii) how to assess in terms of benefit/risk ratio, the implication of any hasty and brutal modification on psychotropic drugs that can induce confusion for a differential diagnosis with the evolution of COVID-19. We carried out a review of the literature aimed at assessing the specific benefit/risk ratio of psychotropic treatments in patients suffering from COVID-19. Clinically, symptoms suggestive of COVID-19 (fever, cough, dyspnea, digestive signs) can be caused by various psychotropic drugs and require vigilance to avoid false negatives and false positives. In infected patients, psychotropic drugs should be used with caution, especially in the elderly, considering the pulmonary risk. Lithium and Clozapine, which are the reference drugs in bipolar disorder and resistant schizophrenia, warrant specific attention. For these two treatments the possibility of a reduction in the dosage - in case of minimal infectious signs and in a situation, which does not allow rapid control - should ideally be considered taking into account the clinical response (even biological; plasma concentrations) observed in the face of previous dose reductions. Tobacco is well identified for its effects as an inducer of CYP1A2 enzyme. In a COVID+ patient, the consequences of an abrupt cessation of smoking, particularly related with the appearance of respiratory symptoms (cough, dyspnea), must therefore be anticipated for patients receiving psychotropics metabolized by CYP1A2. Plasma concentrations of these drugs are expected to decrease and can be related to an increase risk of relapse. The symptomatic treatments used in COVID-19 have frequent interactions with the most used psychotropics. If there is no curative treatment for infection to SARS-CoV-2, the interactions of the various molecules currently tested with several classes of psychotropic drugs (antidepressants, antipsychotics) are important to consider because of the risk of changes in cardiac conduction. Specific knowledge on COVID-19 remains poor today, but we must recommend rigor in this context in the use of psychotropic drugs, to avoid adding, in patients suffering from psychiatric disorders, potentially vulnerable in the epidemic context, an iatrogenic risk or loss of efficiency.

Understanding variability in the pharmacokinetics of atypical antipsychotics - focus on clozapine, olanzapine and aripiprazole population models

Antipsychotic medicines are widely used for the management of psychotic symptoms regardless of the underlying diagnosis. Most atypical antipsychotics undergo extensive metabolism prior to excretion. Various factors may influence their pharmacokinetics, particularly elimination, leading to highly variable drug concentrations between individual patients following the same dosing regimen. Population pharmacokinetic approach, based on nonlinear mixed effects modeling, is a useful tool to identify covariates explaining pharmacokinetic variability, as well as to characterize and distinguish unexplained residual and between-subject (interindividual) variability. In addition, this approach allows the use of both sparsely and intensively sampled data. In this paper, we reviewed the pharmacokinetic characteristics of clozapine, olanzapine and aripiprazole, focusing on a population modeling approach. In particular, models based on a nonlinear mixed effects approach performed by NONMEM^® software in order to identify and quantify sources of pharmacokinetic variability are presented. Population models were identified through systematic searches of PubMed and sixteen studies were selected. Some of the factors identified that significantly contribute to variability in elimination among clozapine, olanzapine, and aripiprazole are demographic characteristics, body weight, genetic polymorphism, smoking and in some cases drug interactions. Scientific research based on pharmacometric modeling is useful to further characterize sources of variability and their combined effect.

Cigarette smoking and heavy coffee consumption affecting response to olanzapine: The role of genetic polymorphism

Objectives: To evaluate the effect of cigarette smoking and heavy coffee consumption on efficacy and safety of olanzapine treatment in schizophrenia patients, in relation to genetic polymorphism.Methods: The study involved 120 patients with schizophrenia, treated with olanzapine for 30 days. Therapy efficacy was determined using three different psychiatric scales, and safety by assessing metabolic adverse effects and extrapyramidal symptoms. Genotyping included CYP1A2*1C, CYP1A2*1F and CYP1A1/1A2 intergenic polymorphism, as well as CYP2D6*3, CYP2D6*4 and CYP2D6*6.Results: Cigarette smoking and heavy coffee consumption decreased the efficacy and increased the safety of olanzapine treatment (P < 0.001). Although the effect was detected only in carriers of CYP1A2*1F allele, covariate analysis revealed that it is independent of CYP1A2 genotype. Olanzapine dose was inversely correlated with the drug efficacy (P ≤ 0.002) and LDL level (P = 0.004). Women and older subjects responded better to therapy (P < 0.026), but had more certain adverse effects (P ≤ 0.049). When controlling for other relevant factors, CYP2D6 metabolizer status affects olanzapine efficacy (P = 0.032).Conclusions: We confirm the effect of cigarette smoking and heavy coffee consumption on olanzapine efficacy and safety. The relevance of CYP1A2 genotype for the described effect needs further investigation. Olanzapine treatment outcome is also affected by dose, sex, age and CYP2D6 metabolizer status.

Prevalence of metabolic syndrome and its associated risk factors in an African-Caribbean population with severe mental illness

This cross-sectional study aims to determine the prevalence of metabolic syndrome (MetS) in patients with severe mental illness (SMI) on a Caribbean island, Curaçao, using the modified National Cholesterol Education Program Adult Treatment Panel III criteria. Among 350 patients (240 men and 110 women) with a mean age of 51.9 years (S.D.=13.5) MetS prevalence was 37.4%, significantly higher in female patients (63.6%) compared to male patients (25.4%). Increased waist circumference was present in 51.1%, low HDL in 50.6%, hypertension in 49.4%, hyperglycemia in 28.6% and 25.7% had hypertriglyceridemia. Except for hypertriglyceridemia, all criteria were more prevalent in female patients. Binary logistic regression analysis indicated that female gender, outpatient treatment setting and the absence of substance use disorder were all significant predictors for MetS. Compared to data from the general population obtained by the 2013 National Health Survey Curaçao, this study showed significantly higher prevalence of diabetes and hypertension in patients with SMI. Moreover, female patients had the highest prevalence of diabetes (28.2%), obesity (50.0%) and increased waist circumference (88.2%). This study demonstrates that African-Caribbean patients with SMI are at high-risk for MetS, especially female patients. Our data suggest to focus on modifiable lifestyle risk factors, as promoting physical activity and healthy dietary habits.

Effect of fluvoxamine augmentation and smoking on clozapine serum concentrations

BACKGROUND

Clozapine (CLZ) is metabolized via cytochrome P450 CYP1A2 to N-desmethylclozapine (NCLZ). Smoking induces CYP1A2 thereby increasing clozapine metabolism whereas fluvoxamine inhibits CYP1A2. Studies suggest that the beneficial effect of fluvoxamine augmentation in raising serum clozapine concentrations also occurs when serum concentrations are low due to smoking. Yet, little is known about the influence of fluvoxamine augmentation on clozapine serum concentrations in smoking versus non-smoking patients.

METHODS

A TDM database was analyzed. Serum concentrations of CLZ, NCLZ, dose-adjusted serum concentrations (C/D) and metabolite-to-parent ratios (MPR) were compared using non-parametrical tests in four groups: clozapine-monotherapy in non-smokers (V_NS, n = 28) and smokers (V_S, n = 43); combined treatment with clozapine and fluvoxamine in non-smokers (V_NS+F, n = 11) and smokers (V_S+F, n = 43).

RESULTS

The CLZ monotherapy smoking group showed lower values of C/D CLZ of -38.6% (p < 0.001), C/D NCLZ -35.6% (p < 0.001) and a higher MPR (p = 0.021) than in the non-smoking group. The combination of CLZ and fluvoxamine in non-smoking patients led to higher C/D values: C/D CLZ +117.9% (p < 0.001), C/D NCLZ +60.8% (p = 0.029) while the MPR did not differ between groups (p = 0.089). Changes were comparable to fluvoxamine augmentation in the smoking group with increased C/D CLZ of +120.1% (p < 0.001), C/D NCLZ of +85.8% (p < 0.001) and lower MPR (p = 0.006).

CONCLUSIONS

Smoking in clozapine monotherapy reduced median dose-adjusted serum concentrations more than a third. Combined treatment with fluvoxamine and clozapine led to higher median C/D values in both, smokers and non-smokers. The opposing effects of CYP1A2 induction by smoking and inhibition by fluvoxamine on clozapine serum concentrations balanced out.

Clozapine Metabolism in East Asians and Caucasians: A Pilot Exploration of the Prevalence of Poor Metabolizers and a Systematic Review

PURPOSE/BACKGROUND

In clozapine therapeutic drug monitoring (TDM) studies, Chinese reached the same concentrations using half the dosage Caucasians use. Defining clozapine poor metabolizers (PMs) requires stratification by ethnicity, smoking, and sex.

METHODS/PROCEDURES

After sex and smoking stratification in 129 Chinese inpatients (mean, 8.8 TDM samples per patient), we explored the association between the total concentration-dose (C/D) ratio and CYP1A2 (*1C, *1F, and *7) and CYP2C19 alleles (*2 and *3). A systematic literature review identified 22 clozapine TDM prior studies (13 in Caucasians and 7 in East Asians).

FINDINGS/RESULTS

In our Chinese sample, the mean total clozapine C/D ratio (ng/mL per mg/d) was 1.96 for 22 male smokers, 2.07 for 5 female smokers, 2.47 for 36 male nonsmokers, and 2.95 for 66 female nonsmokers. CYP1A2 *1C had no significant effects, and CYP1A2 *1F had small effects. Five clozapine PMs (4%) needed low clozapine doses of 75 to 115 mg/d to get therapeutic concentrations. Using the same methodology in a published Italian sample, we found 5 PMs (3.3% of 152). In the systematic review, the clozapine C/D ratio (ng/mL per mg/d) was higher when comparing: (1) weighted mean values of 1.57 in 876 East Asians versus 1.07 in 1147 Caucasians and (2) ranks of 8 East Asians versus 13 Caucasian samples (P < 0.001).

IMPLICATIONS/CONCLUSIONS

Future TDM studies need to further explore the frequency of clozapine PMs after sex and smoking stratification in East Asian and Caucasian patients. Compared with Caucasians, East Asians appear to have a clinically relevant decrease in clozapine clearance.