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

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, specialised tools are used. Three tools have been proven useful to personalise 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 45 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 optimise treatment effects, minimise side effects and ultimately reduce the global burden of diseases, personalised drug treatment has not yet become the standard of care in psychiatry.

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.

Impact of age, sex and cytochrome P450 genotype on quetiapine and N-desalkylquetiapine serum concentrations: A study based on real-world data from 8118 patients

AIMS

To investigate the effect of aging, sex and cytochrome P450 (CYP) genotypes on the exposure of quetiapine (QUE) and the pharmacologically active metabolite N-desalkylquetiapine (NDQ).

METHODS

Patients with serum concentrations of QUE and NDQ were included retrospectively from a therapeutic drug monitoring service. The outcome measures were concentration:dose (C:D) ratios of QUE and NDQ, and NDQ:QUE metabolic ratio. Linear mixed model analyses were used to evaluate the effects of age, sex and, subsequently, CYP2D6/3A genotypes.

RESULTS

The average age of the included population (n = 8118 patients) was 44 years (13.5% ≥65 years). The C:D ratio of QUE and NDQ gradually increased in patients aged >50 years compared to those aged 18-30 years, with 28 and 29% increase, respectively, for patients aged >70 years (P < .001). Compared to males, females had 15% lower QUE C:D ratio and 10% higher C:D ratio of NDQ (both P < .001). The NDQ:QUE metabolic ratio was 30% higher in females than in males (P < .001). For females ≥65 years, the NDQ C:D ratio was 36% higher compared to males <65 years (P < .001). A significantly higher NDQ C:D ratio was observed for CYP2D6 intermediate (+7%, P = .012) and poor (+17%, P = .001) compared to normal metabolizers. No effects of CYP3A4*22 and CYP3A5*1 allele variants were observed.

CONCLUSION

This study shows an increase of the QUE and NDQ exposures during aging. Old age, female sex and CYP2D6 allele variants encoding reduced activity are factors associated with high NDQ exposure. Therefore, females ≥65 years carrying CYP2D6 allele variants encoding reduced activity have the highest risk of dose-dependent side effects of NDQ during QUE treatment.

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.

Comparative Safety Signal Assessment of Hospitalization Associated With the Use of Atypical Antipsychotics

Background

Persons with symptoms of psychosis receiving treatment with atypical antipsychotics (AAPs) can experience serious adverse events (AEs) requiring admission to the hospital. The comparative likelihood of AE-related hospitalization following the use of all AAPs has not been fully characterized. Therefore, we evaluated the safety signals of hospitalizations associated with the use of AAPs.

Methods

We conducted a cross-sectional analysis using the FDA Adverse Event Reporting System (FAERS) database (from January 1, 2004, to December 31, 2021) to examine disproportionality in reporting hospitalizations suspected to be associated with 12 AAPs (aripiprazole, asenapine, brexpiprazole, clozapine, iloperidone, lurasidone, olanzapine, paliperidone, and pimavanserin, quetiapine, risperidone, and ziprasidone). Hospitalization in the FAERs database is an outcome that is recorded as a result of an AE occurring at any drug dose. We estimated reporting odds ratios (RORs) by comparing the odds of hospitalization occurring with a particular AAP to the odds of its occurrence with other drugs. In addition, we considered the presence of a significant safety signal when the lower limit of the 95% confidence interval (CI) of the ROR is >1.

Results

A total of 204,287 cases of hospitalizations were reported to the FDA for individuals treated with AAPs. There were significant safety signals of hospitalization associated with using clozapine (ROR, 2.88; 95% CI, 2.84-2.92), olanzapine (ROR, 2.61; 95% CI, 2.57-2.64), quetiapine (ROR, 1.87; 95% CI, 1.85-1.89), risperidone (ROR, 1.41; 95% CI, 1.39-1.43), aripiprazole (ROR, 1.34; 95% CI, 1.32-1.35), and ziprasidone (ROR, 1.14; 95% CI, 1.10-1.18). However, no hospitalization-related safety signals were observed with the use of paliperidone, pimavanserin, iloperidone, asenapine, lurasidone, and brexpiprazole. The ROR estimates were numerically higher among older adults than younger adults.

Conclusions

This cross-sectional assessment of data from FAERs (2004-2021) suggested that users of clozapine, olanzapine, quetiapine, risperidone, aripiprazole, and ziprasidone were more likely to report being hospitalized than users of other AAPs. Given that the FAERs database only contains spontaneous reports of AEs experienced by persons exposed to a drug but without information on exposed persons who did not have an event, a cohort study comparing hospitalizations among new users of individual AAPs against each other is needed to delineate these safety signals further.

Effects of body weight, smoking status, and sex on plasma concentrations of once-monthly paliperidone palmitate

OBJECTIVES

Knowledge about the impact of body composition features on pharmacokinetics of newer long-acting injectable antipsychotics is limited.

METHODS

We analyzed steady-state plasma concentrations of paliperidone in different body mass index (BMI), age, sex, and smoking status patient subgroups treated with once-monthly paliperidone palmitate (PP1M). Paliperidone plasma concentrations and dose-adjusted-plasma concentrations (C/D) from a therapeutic drug monitoring (TDM) database of PP1M-treated patients were compared among normal BMI, overweight, and obese patients as well as between females vs. males, elderly vs. non-elderly, and smokers vs. non-smokers using non-parametric tests.

RESULTS

In a total of 183 PP1M-treated patients, we found highly variable paliperidone plasma concentrations between individuals but no significant effect of PP1M dose or dosing intervals (p> 0.05). C/D ratios were similar in 54 obese, 82 overweight, and 47 normal BMI patients (p> 0.05). Females had 13.7% higher C/D ratios compared to males, yet this difference was not significant (p> 0.05). No differences were found between elderly vs. non-elderly patients or for smokers vs. non-smokers (p> 0.05).

CONCLUSION

Our findings suggest that age, sex, smoking, or body weight may not substantially affect pharmacokinetic indices of PP1M. The high interindividual variation of plasma concentrations implies that TDM may be helpful to enhance PP1M efficacy and tolerability.

Prevention of Chemotherapy-Induced Nausea and Vomiting in the Older Patient: Optimizing Outcomes

Chemotherapy-induced nausea and vomiting (CINV) are still two of the most feared side effects of cancer therapy. Although major progress in the prophylaxis of CINV has been made during the past 40 years, nausea in particular remains a significant problem. Older patients have a lower risk of CINV than younger patients, but are at a higher risk of severe consequences of dehydration and electrolyte disturbances following emesis. Age-related organ deficiencies, comorbidities, polypharmacy, risk of drug–drug interactions, and lack of compliance all need to be addressed in the older patient with cancer at risk of CINV. Guidelines provide evidence-based recommendations for the prophylaxis of CINV, but none of these guidelines offer specific recommendations for older patients with cancer. This means that the recommendations may lead to overtreatment in some older patients. This review describes the development of antiemetic prophylaxis of CINV focusing on older patients, summarizes recommendations from antiemetic guidelines, describes deficiencies in our knowledge of older patients, summarizes necessary precautions, and suggests some future perspectives for antiemetic research in older patients.

A Retrospective Analysis of Steady-State Olanzapine Concentrations in Chinese Patients Using Therapeutic Drug Monitoring: Effects of Valproate and Other Factors

BACKGROUND

The objective of this study was to investigate the serum concentrations of olanzapine in relation to age, sex, and other factors in Chinese patients aged between 10 and 90 years.

METHODS

Data for 884 olanzapine patients, deposited between 2016 and 2017, were retrieved from the therapeutic drug monitoring database of the Affiliated Brain Hospital of Guangzhou Medical University. The effects of covariates on serum olanzapine concentration, dose-normalized concentration (C/D ratio), and normalized concentration (C/D/weight) were investigated.

RESULTS

Generally, male patients had lower olanzapine concentration, C/D ratio, and C/D/weight than female patients (P < 0.001). Smoking and drinking reduced olanzapine concentration, C/D ratio, and C/D/weight (P < 0.001). Coadministration with valproate decreased olanzapine concentration, C/D ratio, and C/D/weight by about 16%, 30%, and 40%, respectively (P < 0.001). Patients younger than 60 years had higher olanzapine concentrations (P < 0.05) but lower C/D ratios and C/D/weight (P < 0.001) than patients older than 60 years. Age was correlated with olanzapine concentration (r = -0.082, P < 0.05), C/D ratio (r = 0.196, P < 0.001), and C/D/weight (r = 0.169, P < 0.001). Sample timing after dose and diagnostic factors also contributed to the olanzapine concentrations. Multiple linear regression analysis revealed significant influences of dosage, age, sex, valproate comedication, smoking, postdose interval, and schizophrenia (vs bipolar affective disorders) on serum olanzapine concentrations.

CONCLUSIONS

The metabolism of olanzapine may be altered by several factors. Patients characterized with a combination of factors may benefit from therapeutic drug monitoring for the adjustment of olanzapine dose to minimize adverse reactions.

Pharmacokinetic Correlates of Once-Monthly Paliperidone Palmitate-Related Adverse Drug Reactions

OBJECTIVE

The objective of this study was to investigate associations between pharmacokinetic correlates and once-monthly paliperidone palmitate (PP1M)-related adverse drug reactions (ADRs).

METHODS

Plasma concentrations and dose-adjusted plasma concentrations ('concentration-by-dose' [C/D]) of paliperidone from a naturalistic therapeutic drug monitoring database of PP1M-treated patients were compared between patients with ADRs, classified according to the Udvalg for Kliniske Undersogelser side-effect rating scales categories, and patients without ADRs. Analyses included non-parametric tests and a logistic regression model with a significance level set at 0.05.

RESULTS

In 172 patients, we found no differences in sex, age, smoking, body mass index, PP1M dose, paliperidone plasma concentrations, and C/D values (p > 0.05) between 44 patients with and 128 patients without PP1M-related ADRs. We did not detect differences when specifying for different types of ADRs (p > 0.05). Injection intervals were shorter in patients with vs patients without ADRs (p = 0.03). The logistic regression did not report effects for sex, plasma concentrations, or C/D values (p > 0.05). Post hoc analyses in male patients receiving PP1M every 28 weeks reported higher paliperidone concentrations and C/D values in patients with vs without ADRs (p = 0.049 and p = 0.022). Within the group of male patients, we found an odds ratio of 3.07 for PP1M-associated ADRs in patients with C/D values above 7.7 (ng/mL)/(mg/day).

CONCLUSIONS

Our findings did not reveal distinct patterns of paliperidone concentrations in patients with PP1M-related ADRs. However, male patients receiving PP1M every 28 days with C/D values higher than 7.7 (ng/mL)/(mg/day) showed a higher risk for ADRs, implying that therapeutic drug monitoring may be useful in assessing the risk of PP1M-related ADRs.

Effects of Dose, Age, Sex, Body Weight, and Smoking on Plasma Concentrations of Olanzapine and N-desmethyl Olanzapine in Inpatients With Schizophrenia

PURPOSE

This study aimed to investigate the combined effects of dose, age, sex, body weight, and smoking on plasma concentrations of olanzapine (OLA) and N-desmethyl olanzapine (DMO) in Chinese inpatients with schizophrenia.

METHODS

A retrospective study including 185 inpatients was conducted. The steady-state plasma concentrations of OLA (COLA) and DMO (CDMO) were measured using high-performance liquid chromatography-tandem mass spectrometry. The combined effects of dose, age, sex, body weight, and smoking on COLA and CDMO were evaluated.

FINDINGS

Multiple linear regression analyses revealed that dose, age, body weight, and smoking had significant effects on COLA and CDMO in inpatients with schizophrenia treated with OLA. The dose was the most important determinant of COLA and CDMO and was positively correlated with both. Furthermore, smokers exhibited a significantly lower COLA and COLA + DMO, whereas higher body weight led to the reduction of COLA, CDMO, and COLA + DMO. Advanced age was associated with lower CDMO.

IMPLICATIONS

These results suggest that dose, age, body weight, and smoking have a significant influence on the plasma concentration of OLA and its metabolite DMO. Clinicians should consider the combined effects when prescribing OLA to patients with schizophrenia.

Impact of age and gender on paliperidone exposure in patients after administration of long-acting injectable formulations-an observational study using blood samples from 1223 patients

PURPOSE

Paliperidone palmitate is an antipsychotic medication available as long-acting injectable (LAI) formulations. The aim of this study was to investigate the effect of age and gender on paliperidone exposure after administration of LAI formulations.

METHODS

Data on serum concentrations of paliperidone from patients using LAI during were included retrospectively from a therapeutic drug monitoring (TDM) service. Information about dose was obtained from the requisition forms. As a measure of exposure, daily dose-adjusted serum concentration (C/D ratio) was used. Based on initial analysis of C/D ratios versus age, a breaking point close to 50 years was observed, thus deciding the grouping of patients as older (≥50 years) or younger (15-49 years). Linear mixed model analyses, allowing multiple measurements per patients, were used.

RESULTS

In total, 1223 patients were included, whereof 1158 patients used paliperidone LAI in once-monthly intervals. In these patients (27.9% older), older patients had significantly higher paliperidone C/D ratio than younger patients (+20%, p<0.001). Compared to males, females had higher C/D ratio (+14%; p<0.001). Subsequently, older female users of once-monthly LAI intervals had 41% higher paliperidone C/D ratios compared to younger males (15.0 vs. 21.2 nM/mg; p<0.001). Compared to females aged 21-30 years, females with high age (≥70 years) had at least 105% higher paliperidone C/D ratio (p<0.001).

CONCLUSION

The present study shows that older age and female gender are associated with higher paliperidone exposure than younger age and males, respectively. Particularly, older female patients (>50 years) are likely exposed to high concentration and cautious dosing in this subgroup is required.

Therapeutic Drug Monitoring of Long-Acting Injectable Antipsychotic Drugs

BACKGROUND

The use of therapeutic drug monitoring (TDM) to guide treatment with long-acting injectable (LAI) antipsychotics, which are increasingly prescribed, remains a matter of debate. The aim of this review was to provide a practical framework for the integration of TDM when switching from an oral formulation to the LAI counterpart, and in maintenance treatment.

METHODS

The authors critically reviewed 3 types of data: (1) positron emission tomography data evaluating dopamine (D2/D3) receptor occupancy related to antipsychotic concentrations in serum or plasma; D2/D3 receptors are embraced as target sites in the brain for antipsychotic efficacy and tolerability, (2) pharmacokinetic studies evaluating the switch from oral to LAI antipsychotics, and (3) pharmacokinetic data for LAI formulations. Based on these data, indications for TDM and therapeutic reference ranges were considered for LAI antipsychotics.

RESULTS

Antipsychotic concentrations in blood exhibited interindividual variability not only under oral but also under LAI formulations because these concentrations are affected by demographic characteristics such as age and sex, genetic peculiarities, and clinical variables, including comedications and comorbidities. Reported data combined with positron emission tomography evidence indicated a trend toward lower concentrations under LAI administration than under oral medications. However, the available evidence is insufficient to recommend LAI-specific therapeutic reference ranges.

CONCLUSIONS

Although TDM evidence for newer LAI formulations is limited, this review suggests the use of TDM when switching an antipsychotic from oral to its LAI formulation. The application of TDM practice is more accurate for dose selection than the use of dose equivalents as it accounts more precisely for individual characteristics.

Impact of age and CYP2D6 genotype on exposure of zuclopenthixol in patients using long-acting injectable versus oral formulation-an observational study including 2044 patients

PURPOSE

Zuclopenthixol is an antipsychotic available as oral and long-acting injectable (LAI) formulations. The aim of this study was to investigate the effect of age on zuclopenthixol exposure during oral and LAI administrations without and with adjustment for CYP2D6 genotype.

METHODS

Data on serum concentrations of zuclopenthixol and CYP2D6 genotype (available for 28.2% of the population) from patients using oral or LAI zuclopenthixol were included retrospectively from a therapeutic drug monitoring service during the period 2005-2019. As a measure of exposure, dose-adjusted serum concentration (C/D ratio) was used. Based on age, patients were grouped to older (≥ 65 years) or younger (18-64 years). Linear mixed model analyses without and with adjustment for CYP2D6 genotype were used.

RESULTS

Serum concentrations of zuclopenthixol from 1145 (14.1% older) and 899 patients (24.6% older) in the LAI and oral groups were included, respectively. Compared with younger patients, older patients had a higher C/D ratio of zuclopenthixol for LAI (+ 25-33%, p < 0.001) and oral formulation (+ 25-29%, p ≤ 0.003) without and with adjustment for CYP2D6 genotype. The doses were lower in older versus younger patients (oral: - 30%; LAI: - 20%; p < 0.001). Compared with the younger LAI users without reduced CYP2D6 function, a higher C/D ratio was observed in the older LAI users with reduced CYP2D6 function (+ 104%, p < 0.001).

CONCLUSION

The present study showed that zuclopenthixol exposure increases in older patients and that the older LAI users with reduced CYP2D6 function are exposed to high serum concentrations. Also, the present study showed that similar dose reductions are required for oral and LAI users.

The Effect of Valproic Acid on Olanzapine Serum Concentration: A Study Including 2791 Patients Treated With Olanzapine Tablets or Long-Acting Injections

BACKGROUND

The combination of olanzapine and valproic acid (VPA) is regularly prescribed in the treatment of bipolar or schizoaffective disorders. The VPA has been shown to reduce olanzapine concentration, but the mechanism behind this interaction remains unknown. We aimed to investigate the effect of VPA on olanzapine concentration during oral versus long-acting injectable (LAI) formulation in a real-life setting.

METHODS

From a therapeutic drug monitoring service, prescribed doses and serum concentrations from 2791 olanzapine-treated patients (9433 measurements) were included.

RESULTS

The number of patients on olanzapine-LAI treatment was 328, whereas 2463 were using oral olanzapine. The frequency of patients comedicated with VPA was 9.4% for olanzapine tablets and 5.8% for olanzapine-LAI. The VPA had no effect on olanzapine dose-adjusted concentrations in LAI users (1.6 vs 1.7 [ng/mL]/[mg/d]; P = 0.38), whereas in the oral group the dose-adjusted olanzapine concentration was lower in VPA users (2.2 vs 2.7 [ng/mL]/[mg/d]; P < 0.001). For smokers in the oral olanzapine group using VPA, 8.7% of the measurements were in the subtherapeutic range (<10 ng/mL) compared with 6.0% in nonusers (P = 0.003).

IMPLICATIONS

These findings show that the VPA-olanzapine interaction involves a presystemic mechanism and is therefore restricted to oral olanzapine treatment. For oral treatment of olanzapine, comedication with VPA implies a risk of insufficient effect, which may be of clinical relevance in smokers in particular. Thus, it is important to be aware of the interaction potential with VPA during oral olanzapine use, whereas for LAI-treated patients fewer precautions are required from a pharmacokinetic point of view.

The Gut Microbiome and Treatment-Resistance in Schizophrenia

The effect of antipsychotic medication is poor in 30-40% of patients with schizophrenia; treatment resistance is usually met with shifts to new drugs or drug augmentation strategies or a trial of clozapine. The purpose of this review was to examine the potential role of intestinal bacteria in the bioavailability of antipsychotic medication and the possibility that parenterally administered antipsychotics might be able to overcome treatment resistance. Databases were searched with appropriate terms to locate relevant papers dealing with the effect of antipsychotic drugs on the gut microbiome and the effect of bacterial metabolizing enzymes on antipsychotic drugs. Also searched were papers addressing the various current parenteral formulations of antipsychotic drugs. Sixty-five recent pertinent papers were reviewed and the results are suggestive of the premise that there is a drug refractory form of psychosis for which the composition of gut bacteria is responsible, and that parenteral drug administration could overcome the problem.

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.

Smoking in schizophrenia: recent findings about an old problem

PURPOSE OF REVIEW

Recent epidemiology, biological and clinical findings correlate high cigarette consumption in patients with schizophrenia, impeding both treatment strategies and the effectiveness of antipsychotics.

RECENT FINDINGS

New data suggests that despite world-wide efforts to curb cigarette consumption, smoking in patients with schizophrenia was still high. Recent reports could not confirm earlier findings regarding smoking's beneficial effects on cognitive dysfunction, however, the association between smoking, positive symptoms and suicidal behavior was revealed. As some patients smoked in an attempt to alleviate extrapyramidal symptoms (EPS) and negative symptoms, the molecular studies shared genetic roots correlating smoking and schizophrenia, revealing that smoking may increase the risk of developing schizophrenia. Preclinical and clinical studies clarified the complex relationship between schizophrenia's pathology and nicotine's effects on the human brain.

SUMMARY

Cigarette smoking continues to adversely affect the health of individuals with schizophrenia. Both smoking and heavy nicotine dependence, given the complex biological findings, might influence symptom severity in patients with schizophrenia. Regardless, ceasing smoking activities is strongly advocated to replace 'self-medication by nicotine' with safer and more effective medications.

One-Year Treatment with Olanzapine Depot in Female Rats: Metabolic Effects

BACKGROUND

Antipsychotic drugs can negatively affect the metabolic status of patients, with olanzapine as one of the most potent drugs. While patients are often medicated for long time periods, experiments in rats typically run for 1 to 12 weeks, showing olanzapine-related weight gain and increased plasma lipid levels, with transcriptional upregulation of lipogenic genes in liver and adipose tissue. It remains unknown whether metabolic status will deteriorate with time.

METHODS

To examine long-term metabolic effects, we administered intramuscular long-acting injections of olanzapine (100 mg/kg BW) or control substance to female rats for up to 13 months.

RESULTS

Exposure to olanzapine long-acting injections led to rapid weight gain, which was sustained throughout the experiment. At 1, 6, and 13 months, plasma lipid levels were measured in separate cohorts of rats, displaying no increase. Hepatic transcription of lipid-related genes was transiently upregulated at 1 month. Glucose and insulin tolerance tests indicated insulin resistance in olanzapine-treated rats after 12 months.

CONCLUSION

Our data show that the continuous increase in body weight in response to long-term olanzapine exposure was accompanied by surprisingly few concomitant changes in plasma lipids and lipogenic gene expression, suggesting that adaptive mechanisms are involved to reduce long-term metabolic adverse effects of this antipsychotic agent in rats.