Pharmacokinetics of sertraline in relation to genetic polymorphism of CYP2C19

Impact of CYP2C19 Genotype on Sertraline and Escitalopram Exposure and Antidepressant Switching Rate: A Retrospective Cohort Study of Chinese Han Patients

Sertraline and escitalopram, commonly used antidepressants in clinical practice, are metabolized by the polymorphic CYP2C19 enzyme. In a large-scale Chinese Han cohort, this study comprehensively examines the influence of CYP2C19 genotype on sertraline and escitalopram exposure, while also evaluating genotype-associated antidepressant switching rates. A total of 525 serum concentration measurements of sertraline in 415 patients and 355 serum concentration measurements of escitalopram in 294 patients were retrospectively included from the therapeutic drug monitoring database of the First Hospital of Hebei Medical University. Patients were categorized into four subgroups based on CYP2C19 genotype: Normal metabolizers (NMs), Rapid metabolizers (RMs), Intermediate metabolizers (IMs), and Poor metabolizers (PMs). Differences in sertraline and escitalopram exposure and antidepressant switching rates were compared between the subgroups, with CYP2C19 NMs set as reference. Compared with the CYP2C19 NMs group, sertraline serum concentrations were significantly increased 2-fold and 1.3-fold in the CYP2C19 PMs and CYP2C19 IMs groups, respectively, and escitalopram serum concentrations were significantly increased 2-fold and 1.2-fold in the CYP2C19 PMs and CYP2C19 IMs groups, respectively. Compared to the CYP2C19 NMs group, the antidepressant switching rate of sertraline in the CYP2C19 PMs and CYP2C19 IMs groups was significantly increased 5.8-fold and 2.8-fold; the antidepressant switching rate of escitalopram in the CYP2C19 RMs, CYP2C19 PMs, and CYP2C19 IMs groups was increased 13.1-fold, 3.7-fold, and 2.4-fold, respectively. The CYP2C19 genotype exerts a substantial influence on the exposure and the antidepressant switching rate of sertraline and escitalopram. CYP2C19 genotyping prior to administering drugs is clinically beneficial.

A population pharmacokinetic model for sertraline in women during the perinatal period-A contribution from the ConcePTION project

AIMS

Sertraline is frequently prescribed for mental health conditions in both pregnant and breastfeeding women. According to the limited available data, only small amounts of sertraline are transferred into human milk, yet with a large amount of unexplained interindividual variability. This study aimed to develop a population pharmacokinetic (popPK) model to describe the pharmacokinetics of sertraline during the perinatal period and explain interindividual variability.

METHODS

Pregnant women treated with sertraline were enrolled in the multicenter prospective cohort SSRI-Breast Milk study. A popPK model for sertraline maternal plasma and breast milk concentrations was developed and allowed estimating the milk-to-plasma ratio (MPR). An additional fetal compartment allowed cord blood concentrations to be described. Several covariates were tested for significance. Ultimately, model-based simulations allowed infant drug exposure through placenta and breast milk under various conditions to be predicted.

RESULTS

Thirty-eight women treated with sertraline were included in the study and provided 89 maternal plasma, 29 cord blood and 107 breast milk samples. Sertraline clearance was reduced by 42% in CYP2C19 poor metabolizers compared to other phenotypes. Doubling milk fat content increased the MPR by 95%. Simulations suggested a median daily infant dosage of 6.9 μg kg-1 after a 50 mg maternal daily dose, representing 0.95% of the weight-adjusted maternal dose. Median cord blood concentrations could range from 3.29 to 33.23 ng mL-1 after maternal daily doses between 25 and 150 mg.

CONCLUSIONS

Infant exposure to sertraline, influenced by CYP2C19 phenotype and breast milk fat content, remains low, providing reassurance regarding the use of sertraline during pregnancy and breastfeeding.

Population Pharmacokinetics of Sertraline in Psychiatric and Substance Use Disorders

This study aimed to characterize the population pharmacokinetics of sertraline in Mexican patients with psychiatric and substance use disorders. Fifty-nine patients (13 to 76 years old) treated with doses of sertraline between 12.5 and 100 mg/day were included. Plasma sertraline concentrations were determined in blood samples and five of the main substances of abuse were determined by rapid tests in urine samples. Demographic, clinical, and pharmacogenetic factors were also evaluated. Population pharmacokinetic analysis was performed using NONMEM software with first-order conditional estimation method. A one-compartment model with proportional residual error adequately described the sertraline concentrations versus time. CYP2D6*2 polymorphism and CYP2C19 phenotypes significantly influenced sertraline clearance, which had a population mean value of 66 L/h in the final model. The absorption constant and volume of distribution were fixed at 0.855 1/h and 20.2 L/kg, respectively. The model explained 11.3% of the interindividual variability in sertraline clearance. The presence of the CYP2D6*2 polymorphism caused a 23.1% decrease in sertraline clearance, whereas patients with intermediate and poor phenotype of CYP2C19 showed 19.06% and 48.26% decreases in sertraline clearance, respectively. The model was internally validated by bootstrap and visual predictive check. Finally, stochastic simulations were performed to propose dosing regimens to achieve therapeutic levels that contribute to improving treatment response.

The Relevance of Integrating CYP2C19 Phenoconversion Effects into Clinical Pharmacogenetics

INTRODUCTION

CYP2D6 and CYP2C19 functional status as defined by genotype is modulated by phenoconversion (PC) due to pharmacokinetic interactions. As of today, there is no data on the effect size of PC for CYP2C19 functional status. The primary aim of this study was to investigate the impact of PC on CYP2C19 functional status.

METHODS

Two patient cohorts (total n=316; 44.2±15.4 years) were investigated for the functional enzyme status of CYP2C19 applying two different correction methods (PCBousman, PCHahn&Roll) as well as serum concentration and metabolite-to-parent ratio of venlafaxine, amitriptyline, mirtazapine, sertraline, escitalopram, risperidone, and quetiapine.

RESULTS

There was a decrease in the number of normal metabolizers of CYP2C19 and an increase in the number of poor metabolizers. When controlled for age, sex, and, in the case of amitriptyline, venlafaxine, and risperidone, CYP2D6 functional enzyme status, an association was observed between the CYP2C19 phenotype/functional enzyme status and serum concentration of amitriptyline, sertraline, and escitalopram.

DISCUSSION

PC of CYP2C19 changes phenotypes but does not improve correlations with serum concentrations. However, only a limited number of patients received perturbators of CYP2C19. Studies with large numbers of patients are still lacking, and thus, it cannot be decided if there are minor differences and which method of correction to use. For the time being, PC is relevant in individual patients treated with CYP2C19-affecting drugs, for example, esomeprazole. To ensure adequate serum concentrations in these patients, this study suggests the use of therapeutic drug monitoring.

Population pharmacokinetic approach to guide personalized sertraline treatment in Chinese patients

Object: Sertraline is a first-line SSRI for the treatment of depression and has the same effectiveness along with a superior safety profile compared to other medications. There are few population pharmacokinetic (PPK) studies of sertraline and a lack of studies in the Chinese population. Therefore, we performed a PPK analysis of Chinese patients treated with sertraline to identify factors that can influence drug exposure. In addition, the dosing and discontinuation regimen of sertraline when applied to adolescents was explored. Methods: Sertraline serum drug concentration data were collected from 140 hospitalized patients to generate a sertraline PPK dataset, and data evaluation and examination of the effects of covariates on drug exposure in the final model were performed using nonlinear mixed-effects models (NONMEM) and first-order conditional estimation with interaction (FOCE-I). Examining rational medication administration and rational withdrawal of sertraline based on significant covariates and final modeling. Results: A one-compartment model with first-order absorption and elimination of sertraline was developed for Chinese patients with psychiatric disorders. Analysis of covariates revealed that age was a covariate that significantly affected sertraline CL/F (P < 0.01) and that sertraline clearance decreased progressively with aging, whereas other factors had no effect on CL/F and V/F of sertraline. In the age range of 11-79, there were 54 adolescent patients (about 1/3) aged 13-18 years, and the safe and effective optimal daily dose for adolescent patients based on the final model simulations was 50-250 mg/d. For adolescent patients, serum concentration fluctuations were moderate for OD doses of 50 mg and 100 mg, using a fixed dose-descent regimen. For patients with OD doses of 150-200 mg and BID doses of 100-200 mg, a more gradual decrease in serum concentration was achieved with a fixed dose interval of 7 or 14 days for 25 mg as the regimen of descent. Conclusions: To our knowledge, this may be the first PPK study of sertraline in Chinese patients. We found that age was an important factor affecting clearance in Chinese patients taking sertraline. Patients taking sertraline may be exposed to increased amounts of sertraline due to decreased clearance with increasing age. The rational dosing and safe discontinuation of sertraline in adolescent patients can be appropriately referenced to the results of the model simulation, thus providing assistance for individualized dosing in adolescents.

Escitalopram and Sertraline Population Pharmacokinetic Analysis in Pediatric Patients

BACKGROUND AND OBJECTIVE

Escitalopram and sertraline are commonly prescribed for anxiety and depressive disorders in children and adolescents. The pharmacokinetics (PK) of these medications have been evaluated in adults and demonstrate extensive variability, but studies in pediatric patients are limited. Therefore, we performed a population PK analysis for escitalopram and sertraline in children and adolescents to characterize the effects of demographic, clinical, and pharmacogenetic factors on drug exposure.

METHODS

A PK dataset was generated by extracting data from the electronic health record and opportunistic sampling of escitalopram- and sertraline-treated psychiatrically hospitalized pediatric patients aged 5-18 years. A population PK analysis of escitalopram and sertraline was performed using NONMEM. Concentration-time profiles were simulated using MwPharm++ to evaluate how covariates included in the final models influence medication exposure and compared to adult therapeutic reference ranges.

RESULTS

The final escitalopram cohort consisted of 315 samples from 288 patients, and the sertraline cohort consisted of 265 samples from 255 patients. A one-compartment model with a proportional residual error model best described the data for both medications. For escitalopram, CYP2C19 phenotype and concomitant CYP2C19 inhibitors affected apparent clearance (CL/F), and normalizing CL/F and apparent volume of distribution (V/F) to body surface area (BSA) improved estimations. The final escitalopram model estimated CL/F and V/F at 14.2 L/h/1.73 m2 and 428 L/1.73 m2, respectively. For sertraline, CYP2C19 phenotype and concomitant CYP2C19 inhibitors influenced CL/F, and empirical allometric scaling of patient body weight on CL/F and V/F was significant. The final sertraline model estimated CL/F and V/F at 124 L/h/70 kg and 4320 L/70 kg, respectively. Normalized trough concentrations (Ctrough) for CYP2C19 poor metabolizers taking escitalopram were 3.98-fold higher compared to normal metabolizers (151.1 ng/mL vs 38.0 ng/mL, p < 0.0001), and normalized Ctrough for CYP2C19 poor metabolizers taking sertraline were 3.23-fold higher compared to normal, rapid, and ultrarapid metabolizers combined (121.7 ng/mL vs 37.68 ng/mL, p < 0.0001). Escitalopram- and sertraline-treated poor metabolizers may benefit from a dose reduction of 50-75% and 25-50%, respectively, to normalize exposure to other phenotypes.

CONCLUSION

To our knowledge, this is the largest population PK analysis of escitalopram and sertraline in pediatric patients. Significant PK variability for both medications was observed and was largely explained by CYP2C19 phenotype. Slower CYP2C19 metabolizers taking escitalopram or sertraline may benefit from dose reductions given increased exposure.

Unveiling behavioral and molecular neuroadaptations related to the antidepressant action of cannabidiol in the unpredictable chronic mild stress model

Introduction: This study aims to further characterize cannabidiol's pharmacological and molecular profile as an antidepressant. Methods: Effects of cannabidiol (CBD), alone or combined with sertraline (STR), were evaluated in male CD1 mice (n = 48) exposed to an unpredictable chronic mild stress (UCMS) procedure. Once the model was established (4 weeks), mice received CBD (20 mg·kg-1, i.p.), STR (10 mg·kg-1, p.o.) or its combination for 28 days. The efficacy of CBD was evaluated using the light-dark box (LDB), elevated plus maze (EPM), tail suspension (TS), sucrose consumption (SC) and novel object recognition (NOR) tests. Gene expression changes in the serotonin transporter, 5-HT1A and 5-HT2A receptors, BDNF, VGlut1 and PPARdelta, were evaluated in the dorsal raphe, hippocampus (Hipp) and amygdala by real-time PCR. Besides, BDNF, NeuN and caspase-3 immunoreactivity were assessed in the Hipp. Results: CBD exerted anxiolytic and antidepressant-like effects at 4 and 7 days of treatment in the LDB and TS tests, respectively. In contrast, STR required 14 days of treatment to show efficacy. CBD improved cognitive impairment and anhedonia more significantly than STR. CBD plus STR showed a similar effect than CBD in the LBD, TST and EPM. However, a worse outcome was observed in the NOR and SI tests. CBD modulates all molecular disturbances induced by UCMS, whereas STR and the combination could not restore 5-HT1A, BDNF and PPARdelta in the Hipp. Discussion: These results pointed out CBD as a potential new antidepressant with faster action and efficiency than STR. Particular attention should be given to the combination of CBD with current SSRI since it appears to produce a negative impact on treatment.

Pharmacogenetic Testing and Therapeutic Drug Monitoring Of Sertraline at a Residential Treatment Center for Children and Adolescents: A Pilot Study

Background: Sertraline is commonly prescribed to children for the treatment of anxiety and major depressive disorder and is metabolized in part by CYP2C19. While dosing recommendations based on CYP2C19 genotype exist, there is sparse data in children on the relationship between sertraline concentrations and CYP2C19 genotype. Additionally, although rarely utilized in the United States, therapeutic drug monitoring can also help to guide dosing. The primary objective of this pilot study was to compare sertraline concentrations with CYP2C19 genotype. Secondary objectives included exploring the feasibility of using pharmacogenetic testing and therapeutic drug monitoring in a residential treatment center for children and adolescents. Methods: This study was a prospective, open-label study of children prescribed sertraline being treated at a residential treatment center for children and adolescents. Individuals were included if they were < 18 years of age, taking sertraline for at least 2 weeks allowing them to reach steady-state concentrations, being treated through the residential treatment program, and able to understand and speak English. Results: A total of 20 participants (80% female) completed all study procedures, including pharmacogenetic testing and therapeutic drug monitoring, with an average age of 15.4 years (range: 9-17 years). Forty percent (n=8) of participants had a diagnosis of Generalized Anxiety Disorder, while 30% (n=6) had a diagnosis of Major Depressive Disorder. Overall, average sertraline and desmethylsertraline concentrations were 21.1 ng/ml (range: 1-78 ng/ml) and 52.4 ng/ml (range: 1-258 n/ml). Based on CYP2C19 genotypes, 60% (n=12) were normal metabolizers, 10% (n=2) were intermediate metabolizers, and 30% (n=6) were rapid metabolizers. Daily sertraline dose (mg/day) accounted for a significant amount of the observed variability in sertraline (p<0.0001; r2=0.62) and desmethylsertraline concentrations (p<0.001; r2=0.45). When comparing weight-based dosing by sertraline and desmethylsertraline concentrations, sertraline daily dose by weight (mg/kg/day) also accounted for a significant amount of the observed variability in sertraline (p<0.0001; r2=0.60) and desmethylsertraline (p<0.0001; r2=0.59) concentrations. Average daily and weight-based doses for CYP2C19 intermediate, normal, and rapid metabolizers were 75 mg/day, 87.5 mg/day, and 79.2 mg/day and 1.5 mg/kg/day, 1.3 mg/kg/day, and 1.1 mg/kg/day, though these were not significantly different. Conclusion: This small, pilot study showed sertraline dose to be significantly associated with sertraline and desmethylsertraline concentrations. No differences were noted between CYP2C19 metabolizer groups, likely due to the limited sample size. These results also suggest that ordering pharmacogenetic testing and therapeutic drug monitoring in the setting of a child and adolescent residential treatment center is feasible.

Pharmacogenetic Dose Modeling Based on CYP2C19 Allelic Phenotypes

Pharmacogenetic variability in drug metabolism leads to patient vulnerability to side effects and to therapeutic failure. Our purpose was to introduce a systematic statistical methodology to estimate quantitative dose adjustments based on pharmacokinetic differences in pharmacogenetic subgroups, addressing the concerns of sparse data, incomplete information on phenotypic groups, and heterogeneity of study design. Data on psychotropic drugs metabolized by the cytochrome P450 enzyme CYP2C19 were used as a case study. CYP2C19 activity scores were estimated, while statistically assessing the influence of methodological differences between studies, and used to estimate dose adjustments in genotypic groups. Modeling effects of activity scores in each substance as a population led to prudential predictions of adjustments when few data were available ('shrinkage'). The best results were obtained with the regularized horseshoe, an innovative Bayesian approach to estimate coefficients viewed as a sample from two populations. This approach was compared to modeling the population of substance as normally distributed, to a more traditional "fixed effects" approach, and to dose adjustments based on weighted means, as in current practice. Modeling strategies were able to assess the influence of study parameters and deliver adjustment levels when necessary, extrapolated to all phenotype groups, as well as their level of uncertainty. In addition, the horseshoe reacted sensitively to small study sizes, and provided conservative estimates of required adjustments.

Pediatric considerations for pharmacogenetic selective serotonin reuptake inhibitors clinical decision support

Pharmacogenetic testing for psychiatry is growing at a rapid pace, with multiple sites utilizing results to help clinical decision-making. Genotype-guided dosing and drug selection have been implemented at several sites, including Vanderbilt University Medical Center, where clinical decision support (CDS) based on pharmacogenetic results went live for selective serotonin reuptake inhibitors in 2020 for both adult and pediatric patients. Effective and appropriate implementation of CYP2D6- and CYP2C19-guided CDS for the pediatric population requires consideration of the evidence for the pharmacogenetic associations, medication indications, and appropriate alternative therapies to be used when a pharmacogenetic contraindication is identified. In this article, we review these pediatric pharmacogenetic considerations for selective serotonin reuptake inhibitor CDS. We include a case study, the current literature supporting clinical recommendations, considerations when designing pediatric CDS, future implications, and examples of sertraline, (es)citalopram, paroxetine, and fluvoxamine alerts.

Changes in Sertraline Plasma Concentrations Across Pregnancy and Postpartum

Major depressive disorder (MDD) is a common disorder in pregnancy. Although sertraline is the most frequently prescribed antidepressant for pregnant people in the United States, limited information about its pharmacokinetics in pregnancy is available. Our objectives were to characterize plasma sertraline concentration to dose (C/D) ratios across pregnancy and postpartum and investigate the effect of pharmacogenetic variability on sertraline elimination. We performed a prospective observational cohort study in people with a singleton pregnancy ≤ 18 weeks gestation and a lifetime diagnosis of MDD at the 3 Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)-funded Obstetrical-Fetal Pharmacology Research Center sites. Subjects (N = 47) were receiving maintenance sertraline therapy and chose to continue it during pregnancy. Blood samples were obtained 24-hours postdose every 4 weeks across pregnancy and twice postpartum for measurement of plasma concentrations of sertraline and desmethylsertraline. Overall mean sertraline C/D ratios were decreased at study onset and remained consistently low until after delivery. During the last 4 weeks of pregnancy the mean sertraline C/D ratio (95% confidence interval (CI)), 0.25 (95% CI, 0.19, 0.3) ng/mL/dose (mg/day), was smaller than the mean ratio at ≥ 8 weeks after delivery, 0.32 (95% CI, 0.27, 0.37) ng/mL/dose (mg/day), a 22% difference. Mean sertraline/desmethylsertraline ratios were highest after birth, which confirmed increased sertraline elimination during pregnancy. Sertraline C/D ratios in participants with functional CYP2C19 activity did not change significantly during pregnancy, whereas ratios in participants with poor or intermediate CYP2C19 activity decreased by 51%. Exploratory pharmacogenomic analysis indicated that pregnant people with poor or intermediate CYP2C19 activity are at risk for subtherapeutic sertraline concentrations during pregnancy.

The effects of antidepressants fluoxetine, sertraline, and amitriptyline on the development of antibiotic resistance in Acinetobacter baumannii

This study investigates the effects of antidepressants fluoxetine, sertraline, and amitriptyline on the development of antibiotic resistance in clinical Acinetobacter baumannii isolates. The isolates were exposed to fluoxetine, sertraline, and amitriptyline for 30 days, respectively. The bacteria that developed resistance to gentamicin, imipenem, colistin, and ciprofloxacin were isolated and expression levels of some antibiotic-resistance genes were determined by quantitative reverse-transcriptase PCR. Before and after the exposure, minimum inhibitory concentration (MIC) values of the bacteria were determined by the microdilution method. The statistical analysis was performed using Student's t test. A time-dependent increase was observed in the number of bacteria that developed resistance and increased the MIC value. After exposure to fluoxetine and sertraline, decreases were observed for efflux and outer membrane porin genes in isolates that developed colistin resistance, and increases were observed in isolates that developed ciprofloxacin resistance. These observations suggest that these antidepressants have similar effects on the development of resistance. While the exposure to fluoxetine did not result in the development of resistance to imipenem, it was observed after exposure to sertraline and amitriptyline, and a common decrease in ompA gene expression was determined in these isolates. To our knowledge, the comparative effects of selected antidepressants on the development of antibiotic resistance in A. baumannii are reported and presented in the literature here for the first time.

Sertraline dosing trends in children and adolescents stratified by CYP2C19 genotype

Aim: Sertraline is a CYP2C19 substrate commonly prescribed to children with anxiety. Materials & methods: This medical record review examined dosing trends and treatment discontinuation in children prescribed sertraline with documented CYP2C19 genotypes. Variables collected included age, weight, diagnosis, concomitant medications, initial sertraline dose, dose changes and CYP2C19 genotypes. Results: A total of 90 individuals (average age: 10.5 years; 40% female) were included. Nearly 80% were prescribed sertraline for anxiety. Initial weight-adjusted doses were similar, but mean weight-adjusted doses of sertraline were 65% higher in increased metabolizers (1.5 mg/kg/day) compared with normal metabolizers (0.91 mg/kg/day; p = 0.067) at the second dose change. Conclusion: While all children started at a similar sertraline dose, different trends in prescribed doses were observed across CYP2C19 genotypes at subsequent dose changes.

Pre-clinical drug-drug interactions (DDIs) of gefitinib with/without losartan and selective serotonin reuptake inhibitors (SSRIs): citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, and venlafaxine

Objective

Methods

Results

Conclusion

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In vitro hepatocytes assays can predict relevant drug-drug interactions (DDIs).

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Proof-of concept data testing can provide a clear insight of multidrug regimen DDIs.

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Classifying drugs as inhibitors/inducers alone cannot successfully identify DDIs.

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Regimens requiring three or more drugs may cause significant DDIs (p-value < 0.05).

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SSRI metabolism by human hepatocytes can be affected by gefitinib and losartan.

Implications of Cannabidiol in Pharmacogenomic-Based Drug Interactions with CYP2C19 Substrates

This is a patient case exploring the importance of evaluating herbal and dietary supplements and how they may impact drug-drug and drug-gene implications based on pharmacogenomics test results. Even though herbal supplements are considered natural by many patients, which is often the reason for starting them, herbal supplements may still be metabolized by the same pathways as other medications, potentially contributing to drug-drug, drug-herb, and drug-gene interactions, and therefore, potentially impacting a patient's response to medications.

Tools for optimising pharmacotherapy in psychiatry (therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests): focus on antidepressants

Objectives: More than 40 drugs are available to treat affective disorders. Individual selection of the optimal drug and dose is required to attain the highest possible efficacy and acceptable tolerability for every patient.Methods: This review, which includes more than 500 articles selected by 30 experts, combines relevant knowledge on studies investigating the pharmacokinetics, pharmacodynamics and pharmacogenetics of 33 antidepressant drugs and of 4 drugs approved for augmentation in cases of insufficient response to antidepressant monotherapy. Such studies typically measure drug concentrations in blood (i.e. therapeutic drug monitoring) and genotype relevant genetic polymorphisms of enzymes, transporters or receptors involved in drug metabolism or mechanism of action. Imaging studies, primarily positron emission tomography that relates drug concentrations in blood and radioligand binding, are considered to quantify target structure occupancy by the antidepressant drugs in vivo. Results: Evidence is given that in vivo imaging, therapeutic drug monitoring and genotyping and/or phenotyping of drug metabolising enzymes should be an integral part in the development of any new antidepressant drug.Conclusions: To guide antidepressant drug therapy in everyday practice, there are multiple indications such as uncertain adherence, polypharmacy, nonresponse and/or adverse reactions under therapeutically recommended doses, where therapeutic drug monitoring and cytochrome P450 genotyping and/or phenotyping should be applied as valid tools of precision medicine.

CYP2C19 polymorphisms are associated with severity of depression at initial evaluation and after the treatment independently of the prescribed medications: 4 weeks prospective study

BACKGROUND

The cytochrome P-450 2C19 (CYP2C19) enzyme is involved in the metabolism of numerous antidepressants. It also metabolises some endogenous substrates, which could also confer to vulnerability. We aimed to establish whether the severity of depression and treatment response are associated with the genetically predicted CYP2C19 phenotype.

METHODS

We assessed the CYP2C19 genotype-predicted metabolic phenotypes (normal, intermediate or ultrarapid, there were no poor metabolisers) in patients with moderate or severe depression. We used the self-rated Beck Depression Inventory-II (BDI-II) scale and the clinician-rated Montgomery-Åsberg Depression Rating Scale (MADRS) at baseline, after 2 and 4 weeks of an empirical treatment trial. Patients and clinicians were blind to the genetic testing results.

RESULTS

Seventy-six patients participated in the present study. At baseline, impaired CYP2C19 metabolisers, compared to normal metabolisers, had higher BDI-II (P = 0.046; ηp2 = 0.08) but not MADRS score. Intermediate metabolisers more often had a diagnosis of severe depression than normal metabolisers (P = 0.003). After 4 weeks of empirical treatment, intermediate metabolisers had significantly higher MADRS and BDI-II scores than normal metabolisers (P = 0.006; ηp2  = 0.131 and P = 0.030; ηp2 = 0.091). These differences were independent of the use of CYP2C19-metabolised medications in the treatment trial, as well as the treatment discrepancy status.

CONCLUSIONS

Intermediate CYP2C19 polymorphism-predicted activity was associated with more severe depression after an empirical treatment trial. The lack of association between the prescription of CYP2C19-metabolised drugs and treatment response calls for a further look into the role of endogenous substrates of CYP2C19.

Reversible Complete Heart Block in a Pregnant Woman Related to Sertraline Treatment

Complete heart block (CHB) is a serious condition, usually affecting older patients. We report a case of CHB in a 31-year-old pregnant woman treated with sertraline in whom atrioventricular (AV) conduction normalized after discontinuation of sertraline. Results of subsequent genetic investigations for inherited cardiomyopathy and ion-channel disease and a pharmacogenetic study of sertraline pharmacokinetics were negative. Reversible CHB in this younger pregnant patient was temporally related to sertraline. This case underlines the importance of identifying reversible causes when a young patient presents with AV block with unknown trajectory and prognosis, as well as regular recording of electrocardiograms in pregnant patients on psychotropic medications.

Citalopram and Cannabidiol: In Vitro and In Vivo Evidence of Pharmacokinetic Interactions Relevant to the Treatment of Anxiety Disorders in Young People

BACKGROUND

Cannabidiol (CBD), a major nonintoxicating constituent of cannabis, exhibits anxiolytic properties in preclinical and human studies and is of interest as a novel intervention for treating anxiety disorders. Existing first-line pharmacotherapies for these disorders include selective serotonin reuptake inhibitor and other antidepressants. Cannabidiol has well-described inhibitory action on cytochrome P450 (CYP450) drug-metabolizing enzymes and significant drug-drug interactions (DDIs) between CBD and various anticonvulsant medications (eg, clobazam) have been described in the treatment of epilepsy. Here, we examined the likelihood of DDIs when CBD is added to medications prescribed in the treatment of anxiety.

METHODS

The effect of CBD on CYP450-mediated metabolism of the commonly used antidepressants fluoxetine, sertraline, citalopram, and mirtazapine were examined in vitro. Cannabidiol-citalopram interactions were also examined in vivo in patients (n = 6) with anxiety disorders on stable treatment with citalopram or escitalopram who received ascending daily doses of adjunctive CBD (200-800 mg) over 12 weeks in a recent clinical trial.

RESULTS

Cannabidiol minimally affected the metabolism of sertraline, fluoxetine, and mirtazapine in vitro. However, CBD significantly inhibited CYP3A4 and CYP2C19-mediated metabolism of citalopram and its stereoisomer escitalopram at physiologically relevant concentrations, suggesting a possible in vivo DDI. In patients on citalopram or escitalopram, the addition of CBD significantly increased citalopram plasma concentrations, although it was uncertain whether this also increased selective serotonin reuptake inhibitor-mediated adverse events.

CONCLUSIONS

Further pharmacokinetic examination of the interaction between CBD and citalopram/escitalopram is clearly warranted, and clinicians should be vigilant around the possibility of treatment-emergent adverse effects when CBD is introduced to patients taking these antidepressants.

Pharmacogenetic/Pharmacogenomic Tests for Treatment Prediction in Depression

Genetic factors play a significant but complex role in antidepressant (AD) response and tolerability. During recent years, there is growing enthusiasm in the promise of pharmacogenetic/pharmacogenomic (PGx) tools for optimizing and personalizing treatment outcomes for patients with major depressive disorder (MDD). The influence of pharmacokinetic and pharmacodynamic genes on response and tolerability has been investigated, including those encoding the cytochrome P450 superfamily, P-glycoprotein, monoaminergic transporters and receptors, intracellular signal transduction pathways, and the stress hormone system. Genome-wide association studies are also identifying new genetic variants associated with AD response phenotypes, which, combined with methods such as polygenic risk scores (PRS), is opening up new avenues for novel personalized treatment approaches for MDD. This chapter describes the basic concepts in PGx of AD response, reviews the major pharmacokinetic and pharmacodynamic genes involved in AD outcome, discusses PRS as a promising approach for predicting AD efficacy and tolerability, and addresses key challenges to the development and application of PGx tests.

Clinical Relevance of Pharmacogenetics in Serotonin Syndrome

Serotonin syndrome is a predictable life-threatening condition that is caused by serotonergic stimulation of the central and peripheral nervous systems. A patient's genetic profile can amplify exposure risk as many serotonergic drugs are metabolized by CYP450 enzymes, and these enzymes may be altered in functionality. We report a case of an elderly man who presented with serotonin syndrome after a dose change in valproic acid 5 weeks prior. His medication list consisted of low-dose serotonergic agents, which is unusual as most cases of serotonin syndrome involve higher doses. A review of his pharmacogenetic profile is presented to retrospectively evaluate the additive risk for serotonin syndrome and implications on resuming serotonergic agents.

Escitalopram in Adolescents With Generalized Anxiety Disorder: A Double-Blind, Randomized, Placebo-Controlled Study

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) are commonly used to treat pediatric anxiety disorders, including generalized anxiety disorder (GAD); however, their efficacy and tolerability are difficult to predict. This study evaluated the efficacy and tolerability of escitalopram in adolescents with GAD (DSM-IV-TR) and the impact of variants in HTR2A and serotonin transporter (SLC6A4) genes and cytochrome P450 2C19 (CYP2C19) phenotypes on response as well as CYP2C19 phenotype on escitalopram pharmacokinetics from February 2015 through November 2018.

METHODS

Patients were treated with escitalopram (forced titration to 15 mg/d, then flexible titration to 20 mg/d) (n = 26, mean ± SD age: 14.8 ± 1.7 years) or placebo (n = 25, mean ± SD age: 14.9 ± 1.6 years) for 8 weeks. Outcomes were the change in scores on the Pediatric Anxiety Rating Scale (PARS) and Clinical Global Impressions (CGI) scales as well as vital signs and adverse events. Plasma escitalopram and desmethylcitalopram area under the curve during 24 hours (AUC0-24) and maximum concentration (Cmax) were determined and compared across CYP2C19 phenotypes.

RESULTS

Escitalopram was superior to placebo for mean ± SD baseline-to-endpoint change in PARS (-8.65 ± 1.3 vs -3.52 ± 1.1, P = .005) and CGI scores, and increasing CYP2C19 metabolism was associated with decreases in escitalopram Cmax (P = .07) and AUC0-24 (P < .05). Vital signs, corrected QT interval, and adverse events were similar in patients who received escitalopram and placebo.

CONCLUSIONS

Escitalopram reduces anxiety symptoms, and pharmacogenetics variables influence the trajectory and magnitude of improvement. Variation in CYP2C19 metabolism accounts for significant differences in escitalopram pharmacokinetics, raising the possibility that CYP2C19 phenotype should be considered when prescribing escitalopram.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02818751.

Population Pharmacokinetics of Sertraline in Healthy Subjects: a Model-Based Meta-analysis

Sertraline pharmacokinetics is poorly understood and highly variable due to large between-subject variability with inconsistent reports for oral bioavailability. The study objective was to characterize sertraline pharmacokinetics by developing and validating a sertraline population pharmacokinetic (PK) model in healthy subjects using published clinical PK data. We carried a systematic literature search in PubMed in October 2015 and identified 27 pharmacokinetic studies of sertraline conducted in healthy adult subjects and reported in the English language. Sixty mean plasma concentration-time profiles made of 748 plasma concentrations following IV, single, and multiple oral doses ranging from 5 to 400 mg were extracted and analyzed for dose proportionality by a log-linear model and fitted to a 2-compartment pharmacokinetic model in NONMEM using a model-based meta-analysis (MBMA) approach. After a single oral dose, sertraline C_max and AUC_∞ increased with dose proportionally between 50 and 200 mg, and bioavailability increased nonlinearly with dose from 5 to 50 mg and plateaued afterwards while T_max and t_1/2 did not change with dose. Following multiple oral doses, C_max and AUC_∞ increased proportionally with dose across the entire dose range (5-200 mg) while bioavailability, T_max, and t_1/2 remained constant with dose. Sertraline absorption was time-dependent and best described by a sigmoidal E_max function of time after dose. Study findings indicate that sertraline PK is linear in healthy adult subjects at doses ≥ 50 mg, and exposures were nonlinear only after single oral doses < 50 mg likely due to reduced bioavailability.

Impact of CYP2C19 genotype on sertraline exposure in 1200 Scandinavian patients

Sertraline is an (SSRI-)antidepressant metabolized by the polymorphic CYP2C19 enzyme. The aim of this study was to investigate the impact of CYP2C19 genotype on the serum concentrations of sertraline in a large patient population. Second, the proportions of patients in the various CYP2C19 genotype-defined subgroups obtaining serum concentrations outside the therapeutic range of sertraline were assessed. A total of 2190 sertraline serum concentration measurements from 1202 patients were included retrospectively from the drug monitoring database at Diakonhjemmet Hospital in Oslo. The patients were divided into CYP2C19 genotype-predicted phenotype subgroups, i.e. normal (NMs), ultra rapid (UMs), intermediate (IMs), and poor metabolisers (PMs). The differences in dose-harmonized serum concentrations of sertraline and N-desmethylsertraline-to-sertraline metabolic ratio were compared between the subgroups, with CYP2C19 NMs set as reference. The patient proportions outside the therapeutic concentration range were also compared between the subgroups with NMs defined as reference. Compared with the CYP2C19 NMs, the sertraline serum concentration was increased 1.38-fold (95% CI 1.26-1.50) and 2.68-fold (95% CI 2.16-3.31) in CYP2C19 IMs and PMs, respectively (p < 0.001), while only a marginally lower serum concentration (-10%) was observed in CYP2C19 UMs (p = 0.012). The odds ratio for having a sertraline concentration above the therapeutic reference range was 1.97 (95% CI 1.21-3.21, p = 0.064) and 8.69 (95% CI 3.88-19.19, p < 0.001) higher for IMs and PMs vs. NMs, respectively. CYP2C19 IMs and PMs obtain significantly higher serum concentrations of sertraline than NMs. Based on the relative differences in serum concentrations compared to NMs, dose reductions of 60% and 25% should be considered in PMs and IMs, respectively, to reduce the risk of sertraline overexposure in these patients.

Gene-Based Dose Optimization in Children

Pharmacogenetics is a key component of precision medicine. Genetic variation in drug metabolism enzymes can lead to variable exposure to drugs and metabolites, potentially leading to inefficacy and drug toxicity. Although the evidence for pharmacogenetic associations in children is not as extensive as for adults, there are several drugs across diverse therapeutic areas with robust pediatric data indicating important, and relatively common, drug-gene interactions. Guidelines to assist gene-based dose optimization are available for codeine, thiopurine drugs, selective serotonin reuptake inhibitors, atomoxetine, tacrolimus, and voriconazole. For each of these drugs, there is an opportunity to clinically implement precision medicine approaches with children for whom genetic test results are known or are obtained at the time of prescribing. For many more drugs that are commonly used in pediatric patients, additional investigation is needed to determine the genetic factors influencing appropriate dose.

Pharmacogenetics of Sertraline Tolerability and Response in Pediatric Anxiety and Depressive Disorders

Objective: To determine whether genetic variants in a pharmacokinetic gene (the number of CYP2C19 reduced function alleles [RFAs]), and in pharmacodynamic genes (HTR2A, SLC6A4, and GRIK4) influence sertraline tolerability and response in a cohort of pediatric patients with anxiety and depressive disorders. Methods: A retrospective analysis was performed using the electronic medical record data of 352 patients <19 years of age being treated for anxiety and/or depressive disorders with sertraline and who underwent routine clinical CYP2C19 genotyping. Additional genotyping and analysis of variants in HTR2A, SLC6A4, and GRIK4 were conducted for 249 patients. Multivariate regression models testing for associations with CYP2C19 were adjusted for concomitant use of interacting medications. Combinatorial classification and regression tree (CART) analyses containing all pharmacokinetic and pharmacodynamic genes and clinical factors were performed. Results: The maximum sertraline dose during the initial titration period of sertraline was inversely associated with the number of CYP2C19 RFAs and sertraline dose at 60 (p = 0.025) and 90 days (p = 0.025). HTR2A rs6313 was associated with sertraline dose (p = 0.011) and time to the average maximum sertraline dose (p = 0.039). Regarding efficacy, the number of CYP2C19 RFAs was not associated with the sertraline dose at the time of response (p = 0.22), whereas for the pharmacodynamic genes, only HTR2A rs6313 was associated with response dose (p = 0.022). An association was observed between predicted expression levels of SLC6A4 and the duration on sertraline (p = 0.025). Combinatorial CART and multivariate regression analyses implicated that pharmacodynamic genes and clinical factors influence the maximum sertraline dose and response dose. The total number of side effects was not associated with any of the variants tested. Conclusion: Both pharmacokinetic and pharmacodynamic factors, in addition to clinical and demographic components, influence sertraline dose, response, and tolerability, thereby necessitating further research to assess for the validity of these pharmacogenetic associations in children and adolescents.

CYP2C19-Guided Escitalopram and Sertraline Dosing in Pediatric Patients: A Pharmacokinetic Modeling Study

Objective: Cytochrome P4502C19 (CYP2C19) is a highly polymorphic gene that encodes an enzyme that metabolizes escitalopram and sertraline, two selective serotonin reuptake inhibitors (SSRIs) that are FDA approved for pediatric use and commonly used to treat anxiety and depressive disorders in youth. Using pharmacokinetic (PK) models in adolescents, we sought to (1) model SSRI dosing across CYP2C19 phenotypes to compare SSRI exposure (area under curve, AUC) and maximum concentration (Cmax), (2) evaluate the impact of b.i.d. dosing (in rapid metabolizers [RM] and ultrarapid metabolizers [UM]) on SSRI exposure and Cmax, and (3) determine pharmacogenomically-informed dosing strategies to provide similar exposure across CYP2C19 phenotypes in adolescents. Methods: Using PK parameters in CYP2C19 phenotype groups and previously reported pediatric PK data for escitalopram and sertraline, we modeled exposure (AUC0-24) and Cmax and determined CYP2C19-guided dosing strategies. Results: Compared with normal CYP2C19 metabolizers treated with either escitalopram or sertraline, Cmax and AUC0-24 were higher in slower metabolizers and lower in patients with increased CYP2C19 activity, although the magnitude of these differences was more pronounced for escitalopram than for sertraline. For escitalopram, poor metabolizers (PMs) require 10 mg/day and UMs require 30 mg/day to achieve an exposure that is equivalent to 20 mg/day in a normal metabolizer (NM). For sertraline, to achieve AUC0-24 and Cmax similar to NMs receiving 150 mg/day, PMs require 100 mg/day, whereas a dose of 200 mg/day was required in rapid and UMs. For UMs, b.i.d. escitalopram dosing was necessary to achieve comparable trough levels and exposure to NMs. Conclusions: This simulation study raises the possibility that achieving similar escitalopram and sertraline plasma concentrations could require dose adjustments in CYP2C19 poor metabolizers and UMs, although the magnitude of these differences were more pronounced for escitalopram than for sertraline. However, prospective trials of pharmacogenomically guided dosing in the pediatric population are needed to extend the findings of these modeling studies.

Pharmacokinetics of serotonergic drugs: focus on OCD

INTRODUCTION

Although the treatment of obsessive-compulsive disorder (OCD), a common, chronic, and disabling psychiatric condition, has significantly improved in the last decades, with the demonstration of the specific effectiveness of serotonin reuptake inhibitors (SRIs), a large proportion of patients still show high relapse rates. In addition, pharmacological treatments should be maintained for years, so that the clinicians should take into account the pharmacokinetic changes in the long-term, which may be responsible for dangerous side effects or interactions. Areas covered: The aim of this paper was to review the literature on the pharmacokinetics of SSRIs and clomipramine, and on their pharmacokinetic parameters in OCD patients. Expert opinion: Although the literature on the pharmacokinetics of both clomipramine and SSRIs is consistent, data on pharmacokinetic parameters in OCD patients are very few. Given the impact of OCD, its chronicity requiring long-term treatments, together with the need to increase the clinical response rate, more studies in this field are urgently required.

Evidence for cardiotoxicity associated with sertraline in rats

Sertraline is an antidepressant that is frequently prescribed to treat depression, obsessive-compulsive disorder, panic disorder, and anxiety. This drug had a safe cardiotoxicity profile, until the reporting of cases of sertraline-associated cardiotoxicities in the early 2000s. Since then, there have been conflicting results on the cardiotoxicity of this drug. In the study reported here we aimed to identify the cardiotoxic effects of sertraline by evaluating serum cardiac biomarkers, such as serum aspartate aminotransferase (AST), creatinine phosphokinase-myoglobin band (CK-MB), lactate dehydrogenase (LDH), and cardiac troponin T (cTn-T) levels as well as electrocardiographic parameters, DNA damage in cardiomyocytes, and histological findings of heart tissue in rats that were administered oral doses of 5, 10, or 20 mg kg-1 of sertraline for 28 days. Additionally, to investigate the possible mechanisms underlying cardiotoxicity, glutathione and malondialdehyde levels in cardiac tissue were determined to evaluate oxidative stress. According to our results, AST, LDH, and cTn-T levels were significantly increased in the 10 and 20 mg kg-1 sertraline groups when compared to the control group. Heart rates were increased, PR intervals prolonged, a short QTc value was observed, and T-wave amplitudes were decreased significantly in the 20 mg kg-1 sertraline group when compared to the control group. Significant DNA damage was observed in the high-dose groups. Histopathological investigations also revealed some degenerative changes in the 10 and 20 mg kg-1 sertraline groups. Glutathione levels were significantly decreased in the 10 and 20 mg kg-1 sertraline groups when compared with the control group. In conclusion, our findings support the cardiotoxic potential of sertraline and also suggest that oxidative stress may play a role in the toxicity of sertraline.

Pharmacotherapy for generalized anxiety disorder in adult and pediatric patients: an evidence-based treatment review

INTRODUCTION

Generalized anxiety disorder (GAD) often begins during adolescence or early adulthood and persists throughout the lifespan. Randomized controlled trials support the efficacy of selective serotonin and selective serotonin norepinephrine reuptake inhibitors (SSRIs and SNRIs, respectively), as well as benzodiazepines, azapirones, anti-adrenergic medications, melatonin analogs, second-generation antipsychotics, kava, and lavender oil in GAD. However, psychopharmacologic treatment selection requires clinicians to consider multiple factors, including age, co-morbidity, and prior treatment. Areas covered: The authors review the literature concerning pharmacotherapy for pediatric and adult patients with GAD with specific commentary on the efficacy and tolerability of selected agents in these age groups. The authors describe an algorithmic approach to the pediatric and adult patient with GAD and highlight considerations for the use of selected medications in these patients. Expert opinion: In adults with GAD, SSRIs and SNRIs represent the first-line psychopharmacologic treatment while second-line pharmacotherapies include buspirone, benzodiazepines, SGAs, and pregabalin. In pediatric patients with GAD, SSRIs should be considered the first line pharmacotherapy and psychotherapy enhances antidepressant response.

Value of Supportive Care Pharmacogenomics in Oncology Practice

Genomic medicine provides opportunities to personalize cancer therapy for an individual patient. Although novel targeted therapies prolong survival, most patients with cancer continue to suffer from burdensome symptoms including pain, depression, neuropathy, nausea and vomiting, and infections, which significantly impair quality of life. Suboptimal management of these symptoms can negatively affect response to cancer treatment and overall prognosis. The effect of genetic variation on drug response-otherwise known as pharmacogenomics-is well documented and directly influences an individual patient's response to antiemetics, opioids, neuromodulators, antidepressants, antifungals, and more. The growing body of pharmacogenomic data can now guide clinicians to select the safest and most effective supportive medications for an individual patient with cancer from the very first prescription. This review outlines a theoretical patient case and the implications of using pharmacogenetic test results to personalize supportive care throughout the cancer care continuum.

IMPLICATIONS FOR PRACTICE

Integration of palliative medicine into the cancer care continuum has resulted in increased quality of life and survival for patients with many cancer types. However, suboptimal management of symptoms such as pain, neuropathy, depression, and nausea and vomiting continues to place a heavy burden on patients with cancer. As demonstrated in this theoretical case, pharmacogenomics can have a major effect on clinical response to medications used to treat these conditions. Recognizing the value of supportive care pharmacogenomics in oncology and application into routine practice offers an objective choice for the safest and most effective treatment compared with the traditional trial and error method.

Effect of Polymorphisms on the Pharmacokinetics, Pharmacodynamics and Safety of Sertraline in Healthy Volunteers

Sertraline is a selective serotonin reuptake inhibitor widely metabolized in the liver by cytochrome P450 (CYP) enzymes. Besides, it is a P-glycoprotein substrate. Moreover, serotonin transporters and serotonin receptors are involved in its efficacy and safety. The aim of this study was to evaluate the role of polymorphisms of metabolizing enzymes, transporters and receptors on the pharmacokinetics, pharmacodynamics and tolerability of sertraline in healthy volunteers. Forty-six healthy volunteers (24 men and 22 women) receiving a 100-mg single oral dose of sertraline were genotyped for 17 genetic variants of CYP enzymes (CYP2B6, CYP2C9, CYP2C19, CYP2D6), ATP-binding cassette subfamily B member 1 (ABCB1), solute carrier family 6 member 4 (SLC6A4), 5-hydroxytryptamine receptor 2A (HTR2A) and 5-hydroxytryptamine receptor 2C (HTR2C) genes. Pharmacokinetic and pharmacodynamic parameters were similar in men and women. Polymorphisms in CYP2C19 and CYP2B6 genes influenced sertraline pharmacokinetics, with a greater effect of CYP2C19. Individuals carrying defective alleles for CYP2C19 and CYP2B6 showed higher area under the curve (AUC) and half-life (T_1/2 ). Moreover, CYP2C19*17 was related to a decreased AUC and T_1/2 . No significant effect was found for polymorphisms in CYP2C9, CYP2D6 and ABCB1 on sertraline pharmacokinetics. Sertraline had a small heart rate-lowering effect, directly related to maximum concentration (C_max ) and the presence of ABCB1 minor alleles. Sertraline had no significant effect on blood pressure and QTc. There was a tendency to present more adverse drug reactions in women and individuals with higher AUC of sertraline, such as CYP2C19 intermediate metabolizers and CYP2B6 G516T T/T individuals.

Clinical Pharmacogenetics of Cytochrome P450-Associated Drugs in Children

Cytochrome P450 (CYP) enzymes are commonly involved in drug metabolism, and genetic variation in the genes encoding CYPs are associated with variable drug response. While genotype-guided therapy has been clinically implemented in adults, these associations are less well established for pediatric patients. In order to understand the frequency of pediatric exposures to drugs with known CYP interactions, we compiled all actionable drug-CYP interactions with a high level of evidence using Clinical Pharmacogenomic Implementation Consortium (CPIC) data and surveyed 10 years of electronic health records (EHR) data for the number of children exposed to CYP-associated drugs. Subsequently, we performed a focused literature review for drugs commonly used in pediatrics, defined as more than 5000 pediatric patients exposed in the decade-long EHR cohort. There were 48 drug-CYP interactions with a high level of evidence in the CPIC database. Of those, only 10 drugs were commonly used in children (ondansetron, oxycodone, codeine, omeprazole, lansoprazole, sertraline, amitriptyline, citalopram, escitalopram, and risperidone). For these drugs, reports of the drug-CYP interaction in cohorts including children were sparse. There are adequate data for implementation of genotype-guided therapy for children for three of the 10 commonly used drugs (codeine, omeprazole and lansoprazole). For the majority of commonly used drugs with known CYP interactions, more data are required to support pharmacogenomic implementation in children.

Clinical significance of CYP2C19 polymorphisms on the metabolism and pharmacokinetics of 11β-hydroxysteroid dehydrogenase type-1 inhibitor BMS-823778

AIMS

BMS-823778 is an inhibitor of 11β-hydroxysteroid dehydrogenase type-1, and thus a potential candidate for Type 2 diabetes treatment. Here, we investigated the metabolism and pharmacokinetics of BMS-823778 to understand its pharmacokinetic variations in early clinical trials.

METHODS

The metabolism of BMS-823778 was characterized in multiple in vitro assays. Pharmacokinetics were evaluated in healthy volunteers, prescreened as CYP2C19 extensive metabolizers (EM) or poor metabolizers (PM), with a single oral dose of [¹⁴ C]BMS-823778 (10 mg, 80 μCi).

RESULTS

Three metabolites (<5%) were identified in human hepatocytes and liver microsomes (HLM) incubations, including two hydroxylated metabolites (M1 and M2) and one glucuronide conjugate (M3). As the most abundant metabolite, M1 was formed mainly through CYP2C19. M1 formation was also correlated with CYP2C19 activities in genotyped HLM. In humans, urinary excretion of dosed radioactivity was significantly higher in EM (68.8%; 95% confidence interval 61.3%, 76.3%) than in PM (47.0%; 43.5%, 50.6%); only small portions (<2%) were present in faeces or bile from both genotypes. In plasma, BMS-823778 exposure in PM was significantly (5.3-fold, P = 0.0097) higher than in EM. Furthermore, total radioactivity exposure was significantly higher (P < 0.01) than BMS-823778 exposure in all groups, indicating the presence of metabolites. M1 was the only metabolite observed in plasma, and much lower in PM. In urine, the amount of M1 and its oxidative metabolite in EM was 7-fold of that in PM, while more glucuronide conjugates of BMS-823778 and M1 were excreted in PM.

CONCLUSIONS

CYP2C19 polymorphisms significantly impacted systemic exposure and metabolism pathways of BMS-823778 in humans.

Quantitative Prediction of Drug-Drug Interactions Involving Inhibitory Metabolites in Drug Development: How Can Physiologically Based Pharmacokinetic Modeling Help?

This subteam under the Drug Metabolism Leadership Group (Innovation and Quality Consortium) investigated the quantitative role of circulating inhibitory metabolites in drug-drug interactions using physiologically based pharmacokinetic (PBPK) modeling. Three drugs with major circulating inhibitory metabolites (amiodarone, gemfibrozil, and sertraline) were systematically evaluated in addition to the literature review of recent examples. The application of PBPK modeling in drug interactions by inhibitory parent-metabolite pairs is described and guidance on strategic application is provided.

Sertraline reduces glutamate uptake in human platelets

Mitochondrial damage and declines in ATP levels have been recently attributed to sertraline. The effects of sertraline on different parameters were investigated in washed platelets from 18 healthy male volunteers, after 24h of drug exposure. Sertraline toxicity was observed only at the highest concentrations, 30 and 100 μM, which significantly reduced platelet viability to 76 ± 3% and 20 ± 2%, respectively. The same concentrations significantly decreased total ATP to 73 ± 3% and 13 ± 2%, respectively. Basal values of glycogen were not significantly affected by sertraline treatment. Glutamate uptake was significantly reduced after treatment with 3, 30 and 100 μM, by 28 ± 6%, 32 ± 5% and 54 ± 4%, respectively. Our data showed that sertraline at therapeutic concentrations does not compromise platelet viability and ATP levels, but they suggest that in a situation where extracellular glutamate levels are potentially increased, sertraline might aggravate an excitotoxic condition.

Evaluation of the relationship between polymorphisms in CYP2C19 and the pharmacokinetics of omeprazole, pantoprazole and rabeprazole

AIM

To evaluate the possible association between polymorphisms in CYP2C19 and the pharmacokinetics of omeprazole, rabeprazole and pantoprazole.

MATERIALS & METHODS

151 healthy volunteers were evaluated for polymorphisms in the CYP2C19 gene using real-time polymerase chain reaction. Plasma concentrations were measured using high-performance liquid chromatography coupled to mass spectrometry.

RESULTS

Carriers of the *2 allele displayed poor metabolism for all the PPIs studied (around 50% decrease in clearance). Subjects with the *17 allele showed a light increase in clearance compared with *1/*1 (not significant).

CONCLUSION

CYP2C19*2 is associated with decreased clearance of all the PPIs, that could be associated with higher drug efficacy. CYP2C19*17 could increase clearance of these drugs, although the effect seems small.

Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2D6 and CYP2C19 Genotypes and Dosing of Selective Serotonin Reuptake Inhibitors

Selective serotonin reuptake inhibitors (SSRIs) are primary treatment options for major depressive and anxiety disorders. CYP2D6 and CYP2C19 polymorphisms can influence the metabolism of SSRIs, thereby affecting drug efficacy and safety. We summarize evidence from the published literature supporting these associations and provide dosing recommendations for fluvoxamine, paroxetine, citalopram, escitalopram, and sertraline based on CYP2D6 and/or CYP2C19 genotype (updates at www.pharmgkb.org).

Effect of proton pump inhibitors on the serum concentrations of the selective serotonin reuptake inhibitors citalopram, escitalopram, and sertraline

Background:

The selective serotonin reuptake inhibitors (SSRIs) citalopram, escitalopram, and sertraline are all metabolized by the cytochrome P-450 isoenzyme CYP2C19, which is inhibited by the proton pump inhibitors (PPIs) omeprazole, esomeprazole, lansoprazole, and pantoprazole. The aim of the present study was to evaluate the effect of these PPIs on the serum concentrations of citalopram, escitalopram, and sertraline.

Methods:

Serum concentrations from patients treated with citalopram, escitalopram, or sertraline were obtained from a routine therapeutic drug monitoring database, and samples from subjects concomitantly using PPIs were identified. Dose-adjusted SSRI serum concentrations were calculated to compare data from those treated and those not treated with PPIs.

Results:

Citalopram concentrations were significantly higher in patients treated with omeprazole (+35.3%; P < 0.001), esomeprazole (+32.8%; P < 0.001), and lansoprazole (+14.7%; P = 0.043). Escitalopram concentrations were significantly higher in patients treated with omeprazole (+93.9%; P < 0.001), esomeprazole (+81.8%; P < 0.001), lansoprazole (+20.1%; P = 0.008), and pantoprazole (+21.6%; P = 0.002). Sertraline concentrations were significantly higher in patients treated with esomeprazole (+38.5%; P = 0.0014).

Conclusions:

The effect of comedication with PPIs on the serum concentration of SSRIs is more pronounced for omeprazole and esomeprazole than for lansoprazole and pantoprazole, and escitalopram is affected to a greater extent than are citalopram and sertraline. When omeprazole or esomeprazole are used in combination with escitalopram, a 50% dose reduction of the latter should be considered.

Effect of Cytochrome P450 polymorphism on the action and metabolism of selective serotonin reuptake inhibitors

INTRODUCTION

The aim of this article is to review the field of clinically relevant pharmacogenetic effects of cytochrome P450 polymorphisms on metabolism, kinetics, and action of selective serotonin reuptake inhibitors (SSRIs).

AREAS COVERED

The relevant literature in humans on the implications of genetic variation on SSRI drug exposure, drug safety, and efficacy was systematically evaluated. There is a large amount of evidence on the influences of CYP polymorphisms on the pharmacokinetics of SSRIs. Regulatory agencies have issued warnings or advice considering dose adjustments in the presence of affected metabolic phenotypes for several SSRIs. Evidence-based dose adjustments for drugs dependent on CYP genotype are available to clinicians. However, few data on the relationship between genetically determined elevated plasma concentrations of SSRIs and specific side effects or therapeutic failure are currently available.

EXPERT OPINION

Genetic polymorphisms in CYP2D6 and CYP2C19 exert large influences on the individual exposure to SSRIs, leading to the aim to achieve similar concentration time courses in different metabolizer phenotypes. The implementation of a stratified approach to medication with SSRIs in different metabolic phenotypes on a rational basis will require new studies assessing the association between clinical outcomes (such as adverse reactions) and genetically determined elevated plasma concentrations.

Evaluation of the pharmacokinetics, safety and clinical efficacy of sertraline used to treat social anxiety

INTRODUCTION

Social anxiety disorder (SAD) is an emerging, often invalidating, syndrome with deep personal, social and psychological implications. While multiple treatment strategies exist, presently none of them can be considered superior to all others.

AREAS COVERED

The aim of this review is to provide the latest information on sertraline (SRT), one of the most important selective serotonin reuptake inhibitors (SSRIs) currently used for the pharmacological therapy of SAD. A literature search was carried out with the keywords 'sertraline', 'social anxiety', 'social phobia' and 'clinical trials'. In this process, particular attention is paid to the pharmacokinetic characteristics of the drug and its safety in clinical use.

EXPERT OPINION

SRT is an effective drug in the treatment of SAD, especially when used in combination with some form of psychological support. While it does not seem to be significantly more effective than other SSRIs, SRT could offer some peculiar advantages: for example, it has a long half-life, allowing a single daily administration, and seems to be particularly indicated for the control of specific symptoms of SAD.

Influence of Azimilide on CYP2C19-Mediated Metabolism

The purpose of this study was to assess the influence of multiple-dose oral administration of azimilide dihydrochloride on CYP2C19-mediated metabolism. A two-period, randomized crossover study was conducted in 40 healthy male subjects who were phenotyped as extensive CYP2C19 metabolizers. Oral doses of placebo or 125 mg of azimilide dihydrochloride were administered every 12 hours for 3 days, followed by every 24 hours for 5 days; 20 mg omeprazole was coadministered on Day 8. Blood or plasma samples were obtained over 24 hours and analyzed for azimilide or omeprazole/5-hydroxyomeprazole using high-performance liquid chromatography with tandem mass spectrometry. Data were analyzed using "noncompartmental" analysis. Azimilide blood concentrations observed in this study were similar to those previously observed at steady state in patients. Based on AUC(m)/AUC(p) for omeprazole, azimilide does not significantly inhibit CYP2C19-mediated metabolism (90% confidence interval [CI] = 104%-111%). For 5-hydroxyomeprazole, no significant changes in pharmacokinetics were observed. For omeprazole, a statistically significant decrease ( approximately 12%) was observed for AUC. However, this change was small and is not expected to be clinically important since the CI was contained within those used to establish bioequivalence. These results indicate that azimilide does not inhibit CYP2C19-mediated metabolism. Since this isozyme had the lowest in vitro IC(50) values for the cytochrome P450s most commonly involved with the metabolism of drugs (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4), azimilide-related drug interactions mediated via these isozymes are not anticipated.

Genetic variability of drug-metabolizing enzymes: the dual impact on psychiatric therapy and regulation of brain function

Polymorphic drug-metabolizing enzymes (DMEs) are responsible for the metabolism of the majority of psychotropic drugs. By explaining a large portion of variability in individual drug metabolism, pharmacogenetics offers a diagnostic tool in the burgeoning era of personalized medicine. This review updates existing evidence on the influence of pharmacogenetic variants on drug exposure and discusses the rationale for genetic testing in the clinical context. Dose adjustments based on pharmacogenetic knowledge are the first step to translate pharmacogenetics into clinical practice. However, also clinical factors, such as the consequences on toxicity and therapeutic failure, must be considered to provide clinical recommendations and assess the cost-effectiveness of pharmacogenetic treatment strategies. DME polymorphisms are relevant not only for clinical pharmacology and practice but also for research in psychiatry and neuroscience. Several DMEs, above all the cytochrome P (CYP) enzymes, are expressed in the brain, where they may contribute to the local biochemical homeostasis. Of particular interest is the possibility of DMEs playing a physiological role through their action on endogenous substrates, which may underlie the reported associations between genetic polymorphisms and cognitive function, personality and vulnerability to mental disorders. Neuroimaging studies have recently presented evidence of an effect of the CYP2D6 polymorphism on basic brain function. This review summarizes evidence on the effect of DME polymorphisms on brain function that adds to the well-known effects of DME polymorphisms on pharmacokinetics in explaining the range of phenotypes that are relevant to psychiatric practice.

Psychotropic drug-drug interactions involving P-glycoprotein

Multidrug resistance P-glycoprotein (P-gp; also known as MDR1 and ABCB1) is expressed in the luminal membrane of the small intestine and blood-brain barrier, and the apical membranes of excretory cells such as hepatocytes and kidney proximal tubule epithelia. P-gp regulates the absorption and elimination of a wide range of compounds, such as digoxin, paclitaxel, HIV protease inhibitors and psychotropic drugs. Its substrate specificity is as broad as that of cytochrome P450 (CYP) 3A4, which encompasses up to 50 % of the currently marketed drugs. There has been considerable interest in variations in the ABCB1 gene as predictors of the pharmacokinetics and/or treatment outcomes of several drug classes, including antidepressants and antipsychotics. Moreover, P-gp-mediated transport activity is saturable, and is subject to modulation by inhibition and induction, which can affect the pharmacokinetics, efficacy or safety of P-gp substrates. In addition, many of the P-gp substrates overlap with CYP3A4 substrates, and several psychotropic drugs that are P-gp substrates are also CYP3A4 substrates. Therefore, psychotropic drugs that are P-gp substrates may cause a drug interaction when P-gp inhibitors and inducers are coadministered, or when psychotropic drugs or other medicines that are P-gp substrates are added to a prescription. Hence, it is clinically important to accumulate data about drug interactions through studies on P-gp, in addition to CYP3A4, to assist in the selection of appropriate psychotropic medications and in avoiding inappropriate combinations of therapeutic agents. There is currently insufficient information available on the psychotropic drug interactions related to P-gp, and therefore we summarize the recent clinical data in this review.