Effects of age and gender on the serum levels of clozapine, olanzapine, risperidone, and quetiapine

Smoking Is Associated With Lower Dose-Corrected Serum Concentrations of Escitalopram

BACKGROUND

Tobacco smoking rates in depressive patients are higher compared with the general population. Smoking was demonstrated to accelerate the metabolism of different drugs metabolized by CYP1A2, but possibly also by CYP2C19 and CYP3A4. The principle aim of the present investigation from 2015 to 2018 was to determine the differences in the pharmacokinetics of escitalopram between smokers and nonsmokers.

METHODS

A group of nonsmokers (n = 88) was compared with smokers (n = 36), both receiving escitalopram, using the Mann-Whitney U test. Linear regression analysis was used to account for the impact of escitalopram dose, age, and sex in addition to smoking on the steady-state serum concentration of escitalopram.

RESULTS

Smokers received by mean 17.6% higher doses of escitalopram (P = 0.026) but showed 31.9% lower serum concentrations (P = 0.031). To control for confounders, linear regression analysis showed that dose (P < 0.001), sex (P = 0.03), and smoking tobacco (P = 0.027) did significantly influence serum concentrations of escitalopram with higher levels in women and nonsmokers.

CONCLUSIONS

Notwithstanding higher daily doses, smokers had significantly lower serum concentrations of escitalopram. In concordance with previous results, besides CYP1A2, a possible induction of CYP2C19 and CYP3A4 by tobacco smoke, resulting in lower serum concentrations of escitalopram in smokers than in nonsmokers, is suggested. Therefore, to provide personalized therapy, clinicians should consider smoking status and inform patients on the interactions of smoking and escitalopram metabolism.

A Compilation of Serum Concentrations of 12 Antipsychotic Drugs in a Therapeutic Drug Monitoring Setting

BACKGROUND

No comprehensive collection of routine therapeutic drug monitoring data for antipsychotic drugs has been published.

METHODS

In this compilation, data on 12 antipsychotics are presented. The drugs included are amisulpride (n = 506), aripiprazole (n = 1610), clozapine (n = 1189), flupentixol (n = 215), haloperidol (n = 390), olanzapine (n = 10,268), perphenazine (n = 1065), quetiapine (n = 5853), risperidone (n = 3255), sertindole (n = 111), ziprasidone (n = 1235), and zuclopenthixol (n = 691). Because only one sample per patient is included, the number of patients equals the number of samples. For each drug, median serum concentrations as well as that of the 10th and 90th percentiles are given for a range of daily doses. Comparisons are made between males and females, between patients younger than 65 years and 65 years and older, and between those treated with a low and a high dose of each drug. The concentration-to-dose (C/D) ratio is the primary variable used in these comparisons. Coefficients of variation (CVs) for the serum concentrations of each drug within and between subjects are presented.

RESULTS

In general, the C/D ratios were higher in females than in males, higher in those 65 years and older than in younger subjects, and lower in those treated with higher doses than in those treated with lower doses. CVs between individuals were larger than within subjects, and the CVs were highest for the drugs with short elimination half-lives.

CONCLUSIONS

For each antipsychotic drug, the results presented can serve as a reference tool for pharmacokinetic interpretation of the individual patient's serum drug level. The compiled serum concentrations and the C/D ratios can support the physician's decision when individualizing dosing and determining treatment strategies for a specific patient.

Efficacy and safety of 5 mg olanzapine combined with aprepitant, granisetron and dexamethasone to prevent carboplatin-induced nausea and vomiting in patients with gynecologic cancer: A multi-institution phase II study

PURPOSE

The aim of this study was to investigate the efficacy and safety of prophylactic administration of 5 mg olanzapine (OLZ) combined with neurokinin 1 receptor antagonist (NK₁RA), 5-hydroxytryptamine type-3 receptor antagonist (5-HT₃RA), and dexamethasone (DEX) to prevent nausea and vomiting in carboplatin (CBDCA) combination therapy for patients with gynecological cancer.

METHODS

We conducted a single-arm, multi-institution, phase II study. Gynecological cancer patients scheduled to receive AUC ≥4 mg/mL/min CBDCA were enrolled. All patients received 5 mg OLZ (once daily after supper on days 1-4) combined with NK₁RA, 5-HT₃RA, and DEX. The primary end point was complete response (CR; no emesis and rescue therapy) during overall phase (120 h after the start of carboplatin administration).

RESULTS

Between May 2018 and June 2019, 60 patients were enrolled from 3 institutions in Japan. A total of 57 patients who met the criteria were included in the efficacy and safety analysis. The CR rate for the overall phase was 78.9%. Acute (0-24 h) and delayed phases (24-120 h) were 96.5% and 80.7%, respectively. Somnolence was observed in 73.7% patients. However, somnolence of grade 2 or higher was observed in only 3.5% of cases. There were no grade 3 or 4 toxicities associated with OLZ.

CONCLUSIONS

Preventive use of OLZ combined with standard triplet therapy had promising activity with manageable safety, suggesting that this combination could be an effective standard treatment option for patients with AUC ≥4 mg/mL/min CBDCA combination therapy.

Population Pharmacokinetics of Clozapine: A Systematic Review

BACKGROUND AND OBJECTIVE

Clozapine is a second-generation antipsychotic drug that is considered the most effective treatment for refractory schizophrenia. Several clozapine population pharmacokinetic models have been introduced in the last decades. Thus, a systematic review was performed (i) to compare published pharmacokinetics models and (ii) to summarize and explore identified covariates influencing the clozapine pharmacokinetics models.

METHODS

A search of publications for population pharmacokinetic analyses of clozapine either in healthy volunteers or patients from inception to April 2019 was conducted in PubMed and SCOPUS databases. Reviews, methodology articles, in vitro and animal studies, and noncompartmental analysis were excluded.

RESULTS

Twelve studies were included in this review. Clozapine pharmacokinetics was described as one-compartment with first-order absorption and elimination in most of the studies. Significant interindividual variations of clozapine pharmacokinetic parameters were found in most of the included studies. Age, sex, smoking status, and cytochrome P450 1A2 were found to be the most common identified covariates affecting these parameters. External validation was only performed in one study to determine the predictive performance of the models.

CONCLUSIONS

Large pharmacokinetic variability remains despite the inclusion of several covariates. This can be improved by including other potential factors such as genetic polymorphisms, metabolic factors, and significant drug-drug interactions in a well-designed population pharmacokinetic model in the future, taking into account the incorporation of larger sample size and more stringent sampling strategy. External validation should also be performed to the previously published models to compare their predictive performances.

Sex-Specific Associations Between Bipolar Disorder Pharmacological Maintenance Therapies and Inpatient Rehospitalizations: A 9-Year Swedish National Registry Study

Background: Long-term pharmacological maintenance therapy is often essential among people with bipolar disorder to reduce the need for inpatient care. Sex-specific responses to maintenance therapies are expected but remain largely unknown. Here, we examined for sex-specific associations between common maintenance therapies for bipolar disorder with inpatient rehospitalizations following patients' index discharges during 2006-2014. Methods: Population-based data on maintenance therapies and rehospitalizations were extracted from Swedish national registries. We adopted the within-individual design to compare the time on- vs. off- maintenance therapy for males and females, respectively. Extended stratified Cox proportional hazards regression models were employed to quantify the rate of rehospitalization as a function of common maintenance drugs and other important time-varying control variables. Results: Our primary analysis included 22,681 bipolar disorder rehospitalizations by 6,400 males and 9,588 (60.0%) females over an observation time of 62,813 person-years. The time spent on- vs. off- maintenance lithium, lamotrigine, quetiapine, or olanzapine was statistically significant upon adjustment among either sex for reducing the rate of bipolar rehospitalizations. Adjusted sex-specific statistically significant associations were also observed. Among females, the time on- (vs. off-) long-acting injectable risperidone reduced the rate of bipolar rehospitalizations by 73% (56-84%), carbamazepine by 44% (18-62%), aripiprazole by 29% (13-42%), and valproate by 23% (11-33%); whereas among males, ziprasidone by 65% (41-79%). Conclusion: The effectiveness of most maintenance therapies is generally comparable and uniform among both males and females. Despite some statistically significant sex-specific associations, estimates for each drug were fairly consistent between sexes.

Impact of age and CYP2D6 genetics on exposure of aripiprazole and dehydroaripiprazole in patients using long-acting injectable versus oral formulation: relevance of poor and intermediate metabolizer status

PURPOSE

Tailoring medication dosing for the individual patient is complex, and many factors can influence drug exposure. We investigated the effect of age and CYP2D6 genotype on aripiprazole and dehydroaripiprazole exposure in patients using long-acting injectable (LAI) or oral aripiprazole.

METHODS

Matched data on serum concentration of aripiprazole and CYP2D6 genotype of patients using oral or LAI aripiprazole were included retrospectively from a therapeutic drug monitoring service. The patients were divided into the following CYP2D6 genotype-defined categories: poor metabolizers (PMs), intermediate metabolizers (IMs), normal metabolizers (NMs), and ultrarapid metabolizers (UMs). Linear mixed model analyses were used to evaluate the impact of CYP2D6 genotype on dose-adjusted serum concentrations of the active moiety of aripiprazole+dehydroaripiprazole in relation to age and formulation.

RESULTS

We identified 635 patients (mean age = 40.1 years, 9.4% ≥ 65 years, 53.7% females) using LAI (n = 166) or oral formulation (n = 469). The genotype-predicted CYP2D6 phenotype subgroups were 2.4% UMs, 82.0% NMs, 8.0% IMs, and 7.2% PMs. Age did not significantly affect exposure of the active moiety of aripiprazole+dehydroaripiprazole in the LAI (p = 0.071) or oral (p = 0.14) subgroups. Compared with CYP2D6 NMs, PMs and IMs had significantly increased exposure of the active moiety of aripiprazole+dehydroaripiprazole in the LAI (1.7-fold higher, p < 0.001, and 1.5-fold higher, p < 0.001) and oral (1.7-fold higher, p < 0.001, and 1.6-fold higher, p < 0.001) subgroups.

CONCLUSIONS

In conclusion, doses should be adjusted according to CYP2D6 genotype when initiating treatment with aripiprazole LAI or tablets, while advanced age do not affect the exposure of the active moiety of aripiprazole treatment regardless of formulation.

Metabolic and endocrinal effects of N-desmethyl-olanzapine in mice with obesity: Implication for olanzapine-associated metabolic changes

Clinical use of the antipsychotic drug olanzapine (OLA) is associated with metabolic side effects to variable degrees. N-desmethyl-olanzapine (DMO) is one major metabolite of OLA, but its potential involvement in the metabolic responses remains unclear. Here we examined whether DMO can directly impact the metabolic, endocrinal and inflammatory parameters under conditions of metabolic disturbance. DMO administration (2 mg/kg, i.g.) to high-fat diet induced obesity mice for 4 weeks induced a remarkable loss of body weight and fat mass. DMO improved insulin resistance and energy expenditure in mice, but had no significant effects on dyslipidemia or hepatic steatosis. Moreover, DMO induced morphological changes in the white adipose tissue, accompanied by reduced interleukin-1β (IL-1β) production and increased UCP1 expression. These findings demonstrate that DMO is devoid of the metabolic side effects commonly observed for OLA during obesity, which suggests that the N-desmethyl metabolism may function to regulate the metabolic responses to OLA.

Analysis of smoking behavior on the pharmacokinetics of antidepressants and antipsychotics: evidence for the role of alternative pathways apart from CYP1A2

Smoking is common among psychiatric patients and has been shown to accelerate the metabolism of different drugs. We aimed to determine the effect of smoking on the serum concentrations of psychopharmacological drugs in a naturalistic clinical setting. Dose-corrected, steady-state serum concentrations of individual patients were analyzed retrospectively by linear regression including age, sex, and smoking for amitriptyline (n=503), doxepin (n=198), mirtazapine (n=572), venlafaxine (n=534), clozapine (n=106), quetiapine (n=182), and risperidone (n=136). Serum levels of amitriptyline (P=0.038), clozapine (P=0.02), and mirtazapine (P=0.002) were significantly lower in smokers compared with nonsmokers after correction for age and sex. In addition, the ratios of nortriptyline/amitriptyline (P=0.001) and nordoxepin/doxepin (P=0.014) were significantly higher in smokers compared with nonsmokers. Smoking may not only induce CYP1A2, but may possibly also affect CYP2C19. Furthermore, CYP3A4, UGT1A3, and UGT1A4 might be induced by tobacco smoke. Hence, a different dosing strategy is required among smoking and nonsmoking patients. Nevertheless, the clinical relevance of the results remained unclear.

Study protocol for an open-label, single-arm, multicentre phase II trial to evaluate the efficacy and safety of combined triplet therapy and olanzapine for prevention of carboplatin-induced nausea and vomiting in gynaecological cancer patients

INTRODUCTION

Carboplatin (CBDCA) administered at a dosage of 4 mg/mL/min or more area under the blood concentration-time curve (AUC) is considered to be ranked as the highest chemotherapy-induced nausea and vomiting (CINV) risk of the moderately emetogenic chemotherapy agents. The complete response (CR) rate for preventing overall CINV, defined as no emetic episodes and no use of rescue medication, for standard triplet antiemetic therapy (5-HT3RA, 5-hydroxytryptamine-3 receptor antagonist; NK1RA, neurokinin-1 receptor antagonist; DEX, dexamethasone) was approximately 60% in gynaecological cancer patients receiving CBDCA-based therapy. Further improvement in antiemetic treatment is needed to optimise care. This trial is to evaluate the efficacy and safety of using 5 mg olanzapine (OLZ) plus standard triplet antiemetic therapy for CINV after AUC ≥4 mg/mL/min CBDCA combination therapy in gynaecological cancer patients.

METHODS AND ANALYSIS

This trial is an open-label, single-arm, multicentre phase II trial. Patients who receive CBDCA (AUC ≥4)-based therapy and have never been administered moderate to high emetogenic chemotherapy will be enrolled. All patients will receive OLZ (5 mg oral administration on days 1-4, after supper) in combination with 5-HT3RA, NK1RA and DEX. The primary endpoint is the CR rate during the overall period (0-120 hours). Testing the hypothesis that this regimen can improve CR rate from 60% (null hypothesis) to 75% (alternative hypothesis) with a one-sided type I error of 0.1 and power of 0.8 will require 53 patients. Considering the dropout rate, the target sample size is set at 60.

ETHICS AND DISSEMINATION

The study protocol was approved by the institutional review board at each of the participating centres. Data will be presented at international conferences and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

UMIN000031646.

Age Impacts Olanzapine Exposure Differently During Use of Oral Versus Long-Acting Injectable Formulations: An Observational Study Including 8,288 Patients

PURPOSE

Olanzapine is a commonly prescribed antipsychotic available as oral and long-acting injectable (LAI) formulations. Data are lacking on the use and safety of olanzapine-LAI in older patients. The aim of this study was to investigate the effect of increasing age on olanzapine exposure during oral versus LAI administration in a real-life setting.

METHODS

This observational study was based on routine therapeutic drug monitoring data collected during 2005-2017. As a measure of exposure, absolute concentrations and concentration/dose ratios of olanzapine were defined as outcome variables. Linear mixed-model analyzes were used to allow for inclusion of multiple samples per patient and adjustment for covariate effects.

RESULTS

Olanzapine concentrations and doses from 8,288 patients (21,378 measurements) were included. The number of patients on oral treatment was 7,893 (42%, 50 years or older), while 395 were using olanzapine-LAI (27%, 50 years or older). In contrast to oral use, where the dose-adjusted concentration of olanzapine increased significantly for patients 50 years or older (P < 0.001), increasing age had no effect on olanzapine concentration following LAI administration (P = 0.550). The effects of smoking habits and gender were equal in oral and olanzapine-LAI users.

CONCLUSION

While the dose-adjusted systemic exposure of olanzapine increases by age after oral administration, these novel findings from a large patient population show that systemic exposure of olanzapine-LAI is unaffected by age, probably due to the lacking influence of age-related changes in gastrointestinal absorption and/or presystemic metabolism. From a pharmacokinetic point of view, it is therefore no reason to restrict the use of olanzapine-LAI in older patients requiring long-term treatment.

Molecular targets of atypical antipsychotics: From mechanism of action to clinical differences

The introduction of atypical antipsychotics (AAPs) since the discovery of its prototypical drug clozapine has been a revolutionary pharmacological step for treating psychotic patients as these allow a significant recovery not only in terms of hospitalization and reduction in symptoms severity, but also in terms of safety, socialization and better rehabilitation in the society. Regarding the mechanism of action, AAPs are weak D₂ receptor antagonists and they act beyond D₂ antagonism, involving other receptor targets which regulate dopamine and other neurotransmitters. Consequently, AAPs present a significant reduction of deleterious side effects like parkinsonism, hyperprolactinemia, apathy and anhedonia, which are all linked to the strong blockade of D₂ receptors. This review revisits previous and current findings within the class of AAPs and highlights the differences in terms of receptor properties and clinical activities among them. Furthermore, we propose a continuum spectrum of "atypia" that begins with risperidone (the least atypical) to clozapine (the most atypical), while all the other AAPs fall within the extremes of this spectrum. Clozapine is still considered the gold standard in refractory schizophrenia and in psychoses present in Parkinson's disease, though it has been associated with adverse effects like agranulocytosis (0.7%) and weight gain, pushing the scientific community to find new drugs as effective as clozapine, but devoid of its side effects. To achieve this, it is therefore imperative to characterize and compare in depth the very complex molecular profile of AAPs. We also introduce relatively new concepts like biased agonism, receptor dimerization and neurogenesis to identify better the old and new hallmarks of "atypia". Finally, a detailed confrontation of clinical differences among the AAPs is presented, especially in relation to their molecular targets, and new means like therapeutic drug monitoring are also proposed to improve the effectiveness of AAPs in clinical practice.

Use of psychotropic medication in women with psychotic disorders at menopause and beyond

PURPOSE OF REVIEW

Drugs have been extensively prescribed for the treatment of psychotic symptoms in schizophrenia and related disorders, as well as for the management of psychotic features in delirium, dementia and affective disorders. The aim of this narrative review is to focus on the recent literature on drug treatment in women with psychosis at the transition to menopause and subsequently.

RECENT FINDINGS

The recent literature emphasizes the following points: the efficacy of antipsychotic medication in psychosis is largely confined to the alleviation of delusions and hallucinations; menopause and ageing alter the kinetics and dynamics of drug action; drugs other than antipsychotics are currently being tested to address the cognitive, affective and negative symptoms of psychotic illnesses; menopausal symptoms add to comorbidities and require simultaneous treatment, raising the probability of deleterious drug interactions; antipsychotic drugs have many side effects and contribute to high mortality rates in the older psychosis population.

SUMMARY

A major implication for research is that antipsychotic drugs with a wider range of action and with fewer side effects are urgently needed. The clinical implications of the pharmacotherapy of psychotic illness are: older women's needs must be assessed through a comprehensive history and review of systems and physical and mental examination. To avoid adverse effects, drug dosages are best kept low and polypharmacy avoided wherever possible. It is important to frequently reassess older patients, as their pharmacotherapy requirements change with age and with comorbidity.

Pharmacotherapy for schizophrenia in postmenopausal women

INTRODUCTION

Reduced estrogen levels at menopause mean a loss of the neuroprotection that is conferred, from puberty until menopause, on women with schizophrenia. The postmenopausal stage of schizophrenia requires therapeutic attention because women with this diagnosis almost invariably experience increased symptoms and increased side effects at this time. So far, few targeted therapies have been successfully developed.

AREAS COVERED

This non-systematic, narrative review is based on the relevant published literature indexed in PubMed. A digital search was combined with a manual check of references from studies in the field of gender differences, menopause and schizophrenia. Aside from the inclusion of a few early classic papers, the review focuses on 21st century basic, psychopharmacologic, and clinical literature on the treatment of women with schizophrenia after menopause.

EXPERT OPINION

Beyond a relatively low dose threshold, all antipsychotic medications have adverse effects, which become more prominent for women at the time of menopause. Estrogen modulators may not help all symptoms of schizophrenia but are, nevertheless, relatively safe and, when used as adjuncts, help to keep antipsychotic doses low, thus reducing the side effect burden. The field is currently moving towards precision medicine and individual genetic profiles will help to determine the efficacy of available treatments in the future.