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

Therapeutic Drug Monitoring of Olanzapine: Effects of Clinical Factors on Plasma Concentrations in Psychiatric Patients

BACKGROUND

Therapeutic drug monitoring (TDM) is strongly recommended for olanzapine due to its high pharmacokinetic variability. This study aimed to investigate the impact of various clinical factors on olanzapine plasma concentrations in patients with psychiatric disorders.

METHODS

The study used TDM data from the PsyMetab cohort, including 547 daily dose-normalized, steady-state, olanzapine plasma concentrations (C:D ratios) from 248 patients. Both intrinsic factors (eg, sex, age, body weight) and extrinsic factors (eg, smoking status, comedications, hospitalization) were examined. Univariate and multivariable, linear, mixed-effects models were employed, with a stepwise selection procedure based on Akaike information criterion to identify the relevant covariates.

RESULTS

In the multivariable model (based on 440 observations with a complete data set), several significant findings emerged. Olanzapine C:D ratios were significantly lower in smokers (β = -0.65, P < 0.001), valproate users (β = -0.53, P = 0.002), and inpatients (β = -0.20, P = 0.025). Furthermore, the C:D ratios decreased significantly as the time since the last dose increased (β = -0.040, P < 0.001). The male sex had a significant main effect on olanzapine C:D ratios (β = -2.80, P < 0.001), with significant interactions with age (β = 0.025, P < 0.001) and body weight (β = 0.017, P = 0.011). The selected covariates explained 30.3% of the variation in C:D ratios, with smoking status accounting for 7.7% and sex contributing 6.9%. The overall variation explained by both the fixed and random parts of the model was 67.4%. The model facilitated the prediction of olanzapine C:D ratios based on sex, age, and body weight.

CONCLUSIONS

The clinical factors examined in this study, including sex, age, body weight, smoking status, and valproate comedication, remarkably influence olanzapine C:D ratios. Considering these factors, in addition to TDM and the clinical situation, could be important for dose adjustment.

The Association Between Chronic Tobacco Smoking and Brain Alterations in Schizophrenia: A Systematic Review of Magnetic Resonance Imaging Studies

BACKGROUND AND HYPOTHESIS

The high co-occurrence of tobacco smoking in patients with schizophrenia spectrum disorders (SSD) poses a serious health concern, linked to increased mortality and worse clinical outcomes. The mechanisms underlying this co-occurrence are not fully understood.

STUDY DESIGN

Addressing the need for a comprehensive overview of the impact of tobacco use on SSD neurobiology, we conducted a systematic review of neuroimaging studies (including structural, functional, and neurochemical magnetic resonance imaging studies) that investigate the association between chronic tobacco smoking and brain alterations in patients with SSD.

STUDY RESULTS

Eight structural and fourteen functional studies were included. Structural studies show widespread independent and additive reductions in gray matter in relation to smoking and SSD. The majority of functional studies suggest that smoking might be associated with improvements in connectivity deficits linked to SSD. However, the limited number of and high amount of cross-sectional studies, and high between-studies sample overlap prevent a conclusive determination of the nature and extent of the impact of smoking on brain functioning in patients with SSD. Overall, functional results imply a distinct neurobiological mechanism for tobacco addiction in patients with SSD, possibly attributed to differences at the nicotinic acetylcholine receptor level.

CONCLUSIONS

Our findings highlight the need for more longitudinal and exposure-dependent studies to differentiate between inherent neurobiological differences and the (long-term) effects of smoking in SSD, and to unravel the complex interaction between smoking and schizophrenia at various disease stages. This could inform more effective strategies addressing smoking susceptibility in SSD, potentially improving clinical outcomes.

Behind the Curtain: Therapeutic Drug Monitoring of Psychotropic Drugs from a Laboratory Analytical Perspective

PURPOSE

Therapeutic drug monitoring (TDM) is a well-established tool for guiding psychopharmacotherapy and improving patient care. Despite their established roles in the prescription of psychotropic drugs, the "behind the curtain" processes of TDM requests are invariably obscure to clinicians, and literature addressing this topic is scarce.

METHODS

In the present narrative review, we provide a comprehensive overview of the various steps, starting from requesting TDM to interpreting TDM findings, in routine clinical practice. Our goal was to improve clinicians' insights into the numerous factors that may explain the variations in TDM findings due to methodological issues.

RESULTS

We discussed challenges throughout the TDM process, starting from the analyte and its major variation forms, through sampling procedures and pre-analytical conditions, time of blood sampling, sample matrices, and collection tubes, to analytical methods, their advantages and shortcomings, and the applied quality procedures. Additionally, we critically reviewed the current and future advances in the TDM of psychotropic drugs.

CONCLUSIONS

The "behind the curtain" processes enabling TDM involve a multidisciplinary team, which faces numerous challenges in clinical routine. A better understanding of these processes will allow clinicians to join the efforts for achieving higher-quality TDM findings, which will in turn improve treatment effectiveness and safety outcomes of psychotropic agents.

Evaluating Monitoring Guidelines of Clozapine-Induced Adverse Effects: a Systematic Review

BACKGROUND AND OBJECTIVES

Despite the evidence that no other antipsychotic is effective as clozapine for the treatment of resistant schizophrenia, it is associated with various metabolic, neuroendocrine, cardiovascular, and gastrointestinal adverse effects. Guidelines aiming to address the monitoring of clozapine's (serious) adverse effects can be helpful to prevent and treat these effects. However, many of these guidelines seem to lack one or more important monitoring recommendations. We aimed to systematically review the content and quality of existing monitoring guidelines/recommendations for clozapine-induced adverse effects.

METHODS

A comprehensive and systematic literature search, using the MEDLINE, Embase, Web of Science, and Cochrane databases, was conducted for guidelines/recommendations on the monitoring of clozapine-induced adverse events, published between January 2004 and April 2023 (last search 16 April 2023). Only peer-reviewed published guidelines reporting on the comprehensive monitoring of all major clozapine-induced adverse effects and including evidence-based recommendations, developed after the year 2004, were included. Studies reporting on the monitoring of adverse effects of clozapine without being a formal guideline, guidelines reporting on the monitoring of one or a limited number of adverse effects of clozapine, guidelines that were not peer reviewed or published, expert opinion papers without formal consensus guideline development, or guidelines developed before the year 2004, were excluded. The Appraisal of Guidelines for Research and Evaluation II (AGREE-II) tool was used to evaluate the guidelines/recommendations' quality.

RESULTS

Only one guideline met the inclusion criteria. This consensus statement made recommendations for hematological monitoring, and the monitoring of metabolic, cardiac, and three other adverse effects. Highest scores for the qualitative assessment were found for the domains "scope and purpose" (66.7%), "clarity of presentation" (44.4%), and "editorial independence" (66.7%). Lowest scores were found for "rigor of development" (14.6%) and "applicability" (0%).

CONCLUSIONS

Future guidelines should develop more comprehensive recommendations about specific clozapine-induced adverse effects, including constipation, myocarditis, tachycardia, and seizures, as well as include a rechallenge policy. There is an urgent need for well-developed, methodologically stringent, guidelines.

REGISTRATION

PROSPERO registration number, CRD42023402480.

Inflammation affects the pharmacokinetics of risperidone: Does the dose need to be adjusted during the acute-phase reaction?

BACKGROUND

Several studies have indicated that the plasma concentration of risperidone increases 3-5-fold during the acute-phase reaction (APR) of inflammation or infection. Psychiatric symptoms are present or deteriorate when the dose is lowered; thus, the complex effects of inflammation on the pharmacokinetics of risperidone need to be examined.

METHODS

We established a APR model in rabbits induced by lipopolysaccharide (LPS) and studied the effect of APR on pharmacokinetics, distribution and disposition of risperidone in vivo and in vitro.

RESULTS

Following intramuscular administration, the plasma exposures for risperidone and its active metabolite (9-hydroxyrisperidone) were increased approximately 6-fold on day 2 of inflammation. The exposure values did not change between day 2 and 5 of inflammation, nor did the metabolite-to-parent ratio before and during inflammation. Following oral administration, the increase of risperidone exposure was twice as high as that following intramuscular administration during APR. However, the concentration of risperidone and 9-hydroxyrisperidone in brain tissue was similar between the inflammatory and control groups. Moreover, the plasma protein binding (PPB) of risperidone and 9-hydroxyrisperidone associated with inflammation were all increased to >99 %. In addition, risperidone and 9-hydroxyrisperidone were not substrates of the key transporters, OATP1B3, OCT2, OAT3, MATE-1, or MATE-2 K. The expression of progesterone X receptor and P-glycoprotein was inhibited by LPS.

CONCLUSION

During APR, reduced expression of P-glycoprotein and increased PPB were responsible for increased exposure in plasma, while maintaining stable concentrations in the brain, and risperidone does not need to be dose-adjusted so as to achieve psychopharmacological outcomes.

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 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.

Immunological Biomarkers as Predictors of Treatment Response in Psychotic Disorders

Psychotic disorders, notably schizophrenia, impose a detrimental burden on both an individual and a societal level. The mechanisms leading to psychotic disorders are multifaceted, with genetics and environmental factors playing major roles. Increasing evidence additionally implicates neuro-inflammatory processes within at least a subgroup of patients with psychosis. While numerous studies have investigated anti-inflammatory add-on treatments to current antipsychotics, the exploration of immunological biomarkers as a predictor of treatment response remains limited. This review outlines the current evidence from trials exploring the potential of baseline inflammatory biomarkers as predictors of the treatment effect of anti-inflammatory drugs as add-ons to antipsychotics and of antipsychotics alone. Several of the studies have found correlations between baseline immunological biomarkers and treatment response; however, only a few studies incorporated baseline biomarkers as a primary endpoint, and the findings thus need to be interpreted with caution. Our review emphasizes the need for additional research on the potential of repurposing anti-inflammatory drugs while utilizing baseline inflammatory biomarkers as a predictor of treatment response and to identify subgroups of individuals with psychotic disorders where add-on treatment with immunomodulating agents would be warranted. Future studies investigating the correlation between baseline inflammatory markers and treatment responses can pave the way for personalized medicine approaches in psychiatry centred around biomarkers such as specific baseline inflammatory biomarkers in psychotic disorders.

Comparison between cytisine and Nicotine Replacement Therapy in smoking cessation among inpatient psychiatric patients

Introduction: Smoking is more common among people with mental disorders and is associated with adverse effects. Some compounds, including nicotine and cytisine, have been used in many individuals to increase success in smoking cessation. In this study, the effect of cytisine on the smoking status of patients hospitalized in the psychiatry department was investigated.Method: Forty-seven patients, hospitalized in the psychiatry ward, motivated to quit smoking, participated in this open-label randomized trial. Thirty patients used nicotine gums 2 mg (Nicolife®) for eight weeks, and the remaining took cytisine pills (Tabex®) according to the manufacturer's instructions for 25 days. All patients were followed up for six months. The primary outcome was smoking cessation, measured by the mood and physical symptoms scale (MPSS), the AUDIT alcohol consumption questions (AUDIT-C), confirmatory factor analyses, and reliability of the modified cigarette evaluation questionnaire at the end of the 1st week and at 1st, 2nd and 6th months after quit day.Findings: Only two out of 30 patients (6.66%) in the group taking Nicotine Replacement Therapy (NRT) could quit smoking entirely (no cigarettes after six months). In contrast, three out of 17 patients (17.64%) managed to do so in the cytisine group. The number of cigarettes smoked by the patients in both groups decreased, but the reduction was significant in the cytisine group.Conclusion: Cytisine is an effective and suitable agent for smoking cessation in patients with psychological problems, with fewer adverse effects and more success rate compared to NRT.

Recommendations for Reducing the Risk of Cannabis Use-Related Adverse Psychosis Outcomes: A Public Mental Health-Oriented Evidence Review

Objective: Cannabis use is increasingly normalized; psychosis is a major adverse health outcome. We reviewed evidence on cannabis use-related risk factors for psychosis outcomes at different stages toward recommendations for risk reduction by individuals involved in cannabis use. Methods: We searched primary databases for pertinent literature/data 2016 onward, principally relying on reviews and high-quality studies which were narratively summarized and quality-graded; recommendations were developed by international expert consensus. Results: Genetic risks, and mental health/substance use problem histories elevate the risks for cannabis-related psychosis. Early age-of-use-onset, frequency-of-use, product composition (i.e., THC potency), use mode and other substance co-use all influence psychosis risks; the protective effects of CBD are uncertain. Continuous cannabis use may adversely affect psychosis-related treatment and medication effects. Risk factor combinations further amplify the odds of adverse psychosis outcomes. Conclusions: Reductions in the identified cannabis-related risks factors-short of abstinence-may decrease risks of related adverse psychosis outcomes, and thereby protect cannabis users' health.

[Therapeutic drug monitoring of antipsychotic drugs in routine psychiatric practice]

OBJECTIVE

To evaluate the relationship between daily doses of antipsychotic drugs, their serum concentrations, and characteristics of patients treated for schizophrenia or schizophreniform disorder in day-to-day clinical practice.

MATERIAL AND METHODS

A total of 187 patients were included in the study, 77 (41.1%) patients were on monotherapy, and 110 (58.9%) patients received two or more antipsychotics. Patients age was 27.8±8.1 years, and their body weight was 79.8±15.6 kg. The sample was represented mainly by young men (93.0%). The proportion of smokers was 37.4%. The appropriate HPLC-MS/MS method was used for the simultaneous analysis of 8 antipsychotics and its active metabolites. Serum concentrations of the drugs aripiprazole (ARI), chlorpromazine (CPZ), haloperidol (HAL), zuclopenthixol (ZUC), clozapine (CLO), risperidone (RIS), quetiapine (QUE), olanzapine (OLA), norclozapine (N-desmethylclozapine, NOR), 9-hydroxyrisperidone (9-OH-RIS), dehydroaripiprazole (DGA) were measured. The serum concentration/dose ratio (C/D) was employed as the primary outcome measure, as doses were not kept constant during the study. The active antipsychotic fraction (drug+active metabolite, active moiety - AM) was also evaluated for RIS and ARI. In addition, the metabolite/parent ratio (MPR) was evaluated for RIS and ARI.

RESULTS

A total of 265 biological samples were obtained, 421 and 203 measurements of the concentration of drugs and their metabolites were carried out, respectively. Overall, 48% of antipsychotics levels were in the expected therapeutic ranges, 30% were below therapeutic ranges, and 22% were above them. A total of 55 patients underwent dose adjustments or drug changes due to ineffectiveness or side-effects. It has been found that smoking reduces the level of C/D for CLO (p<0.01, Mann-Whitney test). We have established that comedication with CLO significantly increases the C/D ratio of QUE (p<0.05, Mann-Whitney test). We have not revealed any influence of weight and age of the subjects on the C/D. The dose-concentration regression relationships are formalized for all AP.

CONCLUSION

Therapeutical drug monitoring (TDM) is an essential tool to personalize antipsychotic therapy. Careful analysis of TDM data can contribute significantly to the study of the impact of individual patient characteristics on systemic exposure to these drugs.

Current Status of Therapeutic Drug Monitoring in Mental Health Treatment: A Review

Therapeutic drug monitoring (TDM) receives growing interest in different psychiatric clinical settings (emergency, inpatient, and outpatient services). Despite its usefulness, TDM remains underemployed in mental health. This is partly due to the need for evidence about the relationship between drug serum concentration and efficacy and tolerability, both in the general population and even more in subpopulations with atypical pharmacokinetics. This work aims at reviewing the scientific literature published after 2017, when the most recent guidelines about the use of TDM in mental health were written. We found 164 pertinent records that we included in the review. Some promising studies highlighted the possibility of correlating early drug serum concentration and clinical efficacy and safety, especially for antipsychotics, potentially enabling clinicians to make decisions on early laboratory findings and not proceeding by trial and error. About populations with pharmacokinetic peculiarities, the latest studies confirmed very common alterations in drug blood levels in pregnant women, generally with a progressive decrease over pregnancy and a very relevant dose-adjusted concentration increase in the elderly. For adolescents also, several drugs result in having different dose-related concentration values compared to adults. These findings stress the recommendation to use TDM in these populations to ensure a safe and effective treatment. Moreover, the integration of TDM with pharmacogenetic analyses may allow clinicians to adopt precise treatments, addressing therapy on an individual pharmacometabolic basis. Mini-invasive TDM procedures that may be easily performed at home or in a point-of-care are very promising and may represent a turning point toward an extensive real-world TDM application. Although the highlighted recent evidence, research efforts have to be carried on: further studies, especially prospective and fixed-dose, are needed to replicate present findings and provide clearer knowledge on relationships between dose, serum concentration, and efficacy/safety.

Factors Influencing Adherence to Antipsychotic Medications in Women with Delusional Disorder: A Narrative Review

BACKGROUND

Adherence to medication regimens is of great importance in psychiatry because drugs sometimes need to be taken for long durations in order to maintain health and function.

OBJECTIVE

To review influences on adherence to antipsychotic medications, the treatment of choice for delusional disorder (DD), and to focus on adherence in women with DD.

METHOD

A non-systematic narrative review of papers published since 2000 using PubMed and Google Scholar and focusing on women with DD and medication adherence.

RESULTS

Several factors have been identified as exerting influence on adherence in women with persistent delusional symptoms who are treated with antipsychotics. Personality features, intensity of delusion, perception of adverse effects, and cognitive impairment are patient factors. Clinical time spent with the patient, clarity of communication and regular drug monitoring are responsibilities of the health provider. Factors that neither patient nor clinician can control are the social determinants of health such as poverty, easy access to healthcare, and cultural variables.

CONCLUSIONS

There has been little investigation into factors that influence adherence in the target population discussed here -e.g. women with DD. Preliminary results of this literature search indicate that solutions from outside the field of DD may apply to this population. Overall, a solid therapeutic alliance appears to be the best hedge against non-adherence.

An International Adult Guideline for Making Clozapine Titration Safer by Using Six Ancestry-Based Personalized Dosing Titrations, CRP, and Clozapine Levels

This international guideline proposes improving clozapine package inserts worldwide by using ancestry-based dosing and titration. Adverse drug reaction (ADR) databases suggest that clozapine is the third most toxic drug in the United States (US), and it produces four times higher worldwide pneumonia mortality than that by agranulocytosis or myocarditis. For trough steady-state clozapine serum concentrations, the therapeutic reference range is narrow, from 350 to 600 ng/mL with the potential for toxicity and ADRs as concentrations increase. Clozapine is mainly metabolized by CYP1A2 (female non-smokers, the lowest dose; male smokers, the highest dose). Poor metabolizer status through phenotypic conversion is associated with co-prescription of inhibitors (including oral contraceptives and valproate), obesity, or inflammation with C-reactive protein (CRP) elevations. The Asian population (Pakistan to Japan) or the Americas' original inhabitants have lower CYP1A2 activity and require lower clozapine doses to reach concentrations of 350 ng/mL. In the US, daily doses of 300-600 mg/day are recommended. Slow personalized titration may prevent early ADRs (including syncope, myocarditis, and pneumonia). This guideline defines six personalized titration schedules for inpatients: 1) ancestry from Asia or the original people from the Americas with lower metabolism (obesity or valproate) needing minimum therapeutic dosages of 75-150 mg/day, 2) ancestry from Asia or the original people from the Americas with average metabolism needing 175-300 mg/day, 3) European/Western Asian ancestry with lower metabolism (obesity or valproate) needing 100-200 mg/day, 4) European/Western Asian ancestry with average metabolism needing 250-400 mg/day, 5) in the US with ancestries other than from Asia or the original people from the Americas with lower clozapine metabolism (obesity or valproate) needing 150-300 mg/day, and 6) in the US with ancestries other than from Asia or the original people from the Americas with average clozapine metabolism needing 300-600 mg/day. Baseline and weekly CRP monitoring for at least four weeks is required to identify any inflammation, including inflammation secondary to clozapine rapid titration.

[Vaccination Against COVID-19 in Patients Treated with Psychotropic Drugs]

Vaccines against SARS-CoV-2 have been available in the European Union since December 2020. Persons suffering from mental illness have an increased risk of a severe or fatal course following an infection with SARS-CoV-2. Thus, the question arises to what extent interactions between the newly approved vaccines and psychotropic drugs may be expected. Data on the tolerability and efficacy of vaccines against SARS-CoV-2 under treatment with psychotropic drugs are not available to date - however, potential interactions can be derived from previous investigations on vaccines against other pathogens, such as a reduced immune response with lower clinical efficacy and an increase in drug plasma levels due to the indirect vaccine-mediated inhibition of metabolizing enzymes. On the other hand, depressed patients treated with antidepressant medication show a better immune response.