Discovering interactions in polypharmacy: Impact of metamizole on the metabolism of quetiapine.

AIMS: Metamizole is quite an old drug with analgesic, antipyretic and spasmolytic properties. Recent findings have shown that it may induce several cytochrome P450 (CYP) enzymes, especially CYP3A4 and CYP2B6. The clinical relevance of these properties is uncertain. We aimed to unravel potential pharmacokinetic interactions between metamizole and the CYP3A4 substrate quetiapine. METHODS: Plasma concentrations of quetiapine from a large therapeutic drug monitoring database were analysed. Two groups of 33 patients, either receiving quetiapine as a monotherapy (without CYP modulating comedications) or with concomitantly applied metamizole, were compared addressing a potential impact of metamizole on the metabolism of quetiapine being reflected in differences of plasma concentrations of quetiapine and dose-adjusted plasma concentrations. RESULTS: Patients comedicated with metamizole showed >50% lower plasma concentrations of quetiapine (median 45.2 ng/mL, Q1 = 15.5; Q3 = 90.5 vs. 92.0 ng/mL, Q1 = 52.3; Q3 = 203.8, P = .003). The dose-adjusted plasma concentrations were 69% lower in the comedication group (P = .001). Subgroup analyses did not suggest a dose dependency of the metamizole effect or an influence of quetiapine formulation (immediate vs. extended release). Finally, the comedication group exhibited a significantly higher proportion of patients whose quetiapine concentrations were below the therapeutic reference range (78.8% in the metamizole group vs. 54.4% in the control group, P = .037) indicating therapeutically insufficient drug concentrations. CONCLUSION: The combination of metamizole and quetiapine leads to significantly lower drug concentrations of quetiapine, probably via an induction of CYP3A4. Clinicians must consider the risk of adverse drug reactions, especially treatment failure under quetiapine when adding metamizole.

Assessing Pharmacokinetic Correlates of Escitalopram-Related Adverse Drug Reactions.

BACKGROUND: To assess the pharmacokinetic correlates of reported adverse drug reactions (ADRs) under antidepressant treatment with escitalopram (ESC) using a large therapeutic drug monitoring database. METHODS: A large naturalistic sample of inpatients and outpatients prescribed ESC was analyzed. ADRs were classified using the Udvalg for Kliniske Undersogelser side effect rating scale. We compared ESC-treated patients with (n = 35) and without ADRs (n = 273) using ESC plasma concentrations as the primary outcome. We also compared ADR rates in the 2 groups based on 2 cut-off ESC levels reflecting the recommended upper thresholds of the therapeutic reference range of 80 ng/mL, suggested by the consensus therapeutic drug monitoring guidelines, and 40 ng/mL, based on recent meta-analysis data. The effects of age, sex, smoking, daily ESC dose, plasma concentrations, and concentrations corrected for daily dose were included in a binary logistic regression model to predict ADRs. RESULTS: No differences in clinical, demographic, or pharmacokinetic parameters were observed between patients with and without ADRs ( P > 0.05). Patients with ESC-related ADRs were more frequently diagnosed with psychotic disorders than those without (25% vs. 7.1%, P = 0.004). None of the variables was associated with ADR risk. Overall, ADR rates were not significantly different in patients above versus below thresholds of ESC concentrations (ESC concentrations >40 [n = 59] vs. ≤40 ng/mL [n = 249] and >80 [n = 8] vs. ≤80 ng/mL [n = 300]; P = 0.56 and P = 1.0, respectively). CONCLUSIONS: No distinct pharmacokinetic patterns underlying ESC-associated ADRs were observed. Further studies with more specific assessments of ADRs in larger cohorts are required to better identify potential underlying patterns.

Changes in Psychotropic Drug Blood Levels After SARS-CoV-2 Vaccination: A Two-Center Cohort Study.

BACKGROUND: Limited evidence from case reports suggests that coronavirus disease 2019 (COVID-19) vaccination may interact with the treatment outcomes of psychiatric medications. Apart from clozapine, reports on the effect of COVID-19 vaccination on other psychotropic agents are scarce. This study aimed to investigate the impact of COVID-19 vaccination on the plasma levels of different psychotropic drugs using therapeutic drug monitoring. METHODS: Plasma levels of psychotropic agents, including agomelatine, amisulpride, amitriptyline, escitalopram, fluoxetine, lamotrigine, mirtazapine, olanzapine, quetiapine, sertraline, trazodone, and venlafaxine, from inpatients with a broad spectrum of psychiatric diseases receiving COVID-19 vaccinations were collected at 2 medical centers between 08/2021 and 02/2022 under steady-state conditions before and after vaccination. Postvaccination changes were estimated as a percentage of baseline. RESULTS: Data from 16 patients who received COVID-19 vaccination were included. The largest changes in plasma levels were reported for quetiapine (+101.2%) and trazodone (-38.5%) in 1 and 3 patients, respectively, 1 day postvaccination compared with baseline levels. One week postvaccination, the plasma levels of fluoxetine (active moiety) and escitalopram increased by 31% and 24.9%, respectively. CONCLUSIONS: This study provides the first evidence of major changes in the plasma levels of escitalopram, fluoxetine, trazodone, and quetiapine after COVID-19 vaccination. When planning COVID-19 vaccination for patients treated with these medications, clinicians should monitor rapid changes in bioavailability and consider short-term dose adjustments to ensure safety.

Clozapine once- versus multiple-daily dosing: a two-center cross-sectional study, systematic review and meta-analysis.

Evidence regarding effectiveness and safety of clozapine once- vs. multiple-daily dosing is limited. We compared demographic and clinical parameters between patients with once- vs. multiple-daily dosing in the Department of Psychiatry and Psychotherapy, University of Regensburg, Germany (AGATE dataset), and the Department of Psychiatry, Lausanne University Hospital, Switzerland, using non-parametric tests. Effectiveness and safety outcomes were available in the AGATE dataset. We performed a systematic review in PubMed/Embase until February 2022, meta-analyzing studies comparing clozapine once- vs. multiple-daily-dosing. We estimated a pooled odds ratio for adverse drug-induced reactions (ADRs) and meta-analyzed differences regarding clinical symptom severity, age, percentage males, smokers, clozapine dose, and co-medications between patients receiving once- vs. multiple-daily dosing. Study quality was assessed using the Newcastle-Ottawa-Scale. Of 1494 and 174 patients included in AGATE and Lausanne datasets, clozapine was prescribed multiple-daily in 74.8% and 67.8%, respectively. In the AGATE cohort, no differences were reported for the clinical symptoms severity or ADR rate (p > 0.05). Meta-analyzing eight cohorts with a total of 2810 clozapine-treated individuals, we found more severe clinical symptoms (p = 0.036), increased ADR risk (p = 0.01), higher clozapine doses (p < 0.001), more frequent co-medication with other antipsychotics (p < 0.001), benzodiazepines (p < 0.001), anticholinergics (p = 0.039), and laxatives (p < 0.001) in patients on multiple- vs. once-daily dosing. Of six studies, five were rated as good, and one as poor quality. Patients responding less well to clozapine may be prescribed higher doses multiple-daily, also treated with polypharmacy, potentially underlying worse safety outcomes. Patient preferences and adherence should be considered during regimen selection.

[Psychopharmacotherapy during pregnancy and breastfeeding-Part II: focus on breastfeeding : Support options by using therapeutic drug monitoring]. / Psychopharmakotherapie in der Schwangerschaft und Stillzeit ­ Teil II: Schwerpunkt Stillzeit : Möglichkeiten der Unterstützung durch therapeutisches Drug-Monitoring.

The drug treatment of mental disorders during lactation requires special knowledge about the possible effects on the breastfed infant. The first part of this 2­part article is devoted to the use of psychotropic drugs during pregnancy. This second part addresses the use of psychotropic drugs during breastfeeding.The uncertainty about whether maternal breastfeeding can be recommended during drug treatment is high and the clinical management of psychopharmacotherapy during breastfeeding is a major challenge. Due to sparse scientific evidence, the administration of psychotropic drugs must be evaluated individually; however, the risk of mental decompensation of the mother is a weighty factor that can have a very negative impact on the mother-child pair, in the worst case up to suicide or infanticide. Drug treatment during breastfeeding is always off-label and should therefore only be given after a careful risk assessment and comprehensive clarification. Every treatment decision is a case by case decision based on an assessment of the overall constellation. This includes the psychiatric history, the current complaints and a risk assessment for the infant, ideally with the involvement of a social support network in the environment. A multiprofessional support by psychiatrists, pediatricians, gynecologists and midwives should accompany drug treatment during breastfeeding under close monitoring.This second part of the 2­part article provides an overview of the most frequently used drug classes during the breastfeeding period. Therapeutic drug monitoring (TDM) is a valuable tool for risk and exposure assessment during the breastfeeding period.

[Psychopharmacotherapy during pregnancy and breastfeeding-Part I: focus on pregnancy : Support options by using therapeutic drug monitoring]. / Psychopharmakotherapie in Schwangerschaft und Stillzeit ­ Teil I: Schwerpunkt Schwangerschaft : Möglichkeiten der Unterstützung durch therapeutisches Drug-Monitoring.

The medicinal treatment of mental disorders during pregnancy and lactation requires special knowledge about possible effects of the psychopharmacotherapy on the intrauterine exposure of the embryo/fetus. Therefore, the first part of this 2­part article focuses on the use of psychotropic drugs during pregnancy. In the second part, the use of psychotropic drugs during breastfeeding is addressed. Possible substance-specific risks as a consequence of the administration have to be assessed compared to the natural risk of pregnancy complications, birth complications and neonatal complications associated with the appropriate (untreated) mental disease. Pharmacokinetic changes during pregnancy require a special focus on the safety of drug treatment and treatment efficacy. Currently, neither the European Medicines Agency (EMA) nor the U. S. Food and Drug Administration (FDA) has approved any psychotropic drug for use during pregnancy or breastfeeding. A more detailed consideration of the risk profiles of all psychotropic drugs, prescribed off-label during this time, is important. Antidepressants, antipsychotics, and mood stabilizers are the main drugs used, despite their lack of approval. This first part of our 2­part article provides an overview of the most frequently used substance groups during pregnancy and their special characteristics. Therapeutic drug monitoring (TDM) is presented as a clinical tool that can provide a supportive contribution to treatment safety and effectiveness during pregnancy and later also during breastfeeding, not only because of the changing pharmacokinetics. In this context, the measurement of concentrations of the active substance allows a better quantification of the intrauterine and postpartum exposure risk. Despite all clinical support possibilities, each therapeutic decision for the administration of a psychotropic drug remains an individual case decision. For those involved in the treatment, this means a careful balancing of the possible consequences of non-treatment and the possible sequelae of the use of psychopharmacotherapy.

The negative impact of vitamin D on antipsychotic drug exposure may counteract its potential benefits in schizophrenia.

AIMS: Patients with schizophrenia frequently show insufficient vitamin D levels, which are associated with somatic comorbidity and may contribute to psychopathology. For many reasons, vitamin D supplementation may be indicated for this patient cohort. However, there is growing evidence for a vitamin D-mediated increase of drug metabolism by induction of cytochrome P450 (CYP) 3A4. Hence, this study aimed to assess vitamin D's impact on both antipsychotic drug concentrations and psychopathology in a non-interventional manner. METHODS: Totals of 107 serum concentrations of different antipsychotic drugs (amisulpride, aripiprazole, clozapine, olanzapine, quetiapine and risperidone), 80 serum concentrations of vitamin D and psychopathological assessments were obtained from 80 patients with schizophrenia. The impact of Vitamin D on antipsychotic drug concentrations and symptomatology was assessed using a generalized linear model, path and correlation analyses. RESULTS: We observed a negative relationship between vitamin D and dose-adjusted antipsychotic drug concentrations, which was particularly pronounced for drugs which are predominantly metabolized via CYP3A4 (i.e., aripiprazole and quetiapine). A path analysis suggested a relieving effect of vitamin D on symptomatology which was, however, counteracted by its negative impact on antipsychotic drug levels. Finally, patients with vitamin D levels above the median exhibited a significantly higher proportion of therapeutically insufficient dose-normalized drug concentrations of aripiprazole and quetiapine. CONCLUSION: Despite vitamin D's potential benefits on physical and mental health, clinicians should be aware of its negative impact on blood concentrations of antipsychotics metabolized by CYP3A4 in patients with schizophrenia. Therefore, when considering its supplementation, therapeutic drug monitoring should be applied to guide dose adjustment.

Metamizole but not ibuprofen reduces the plasma concentration of sertraline: Implications for the concurrent treatment of pain and depression/anxiety disorders.

AIM: Comorbidity of pain and depression or anxiety is a challenging clinical phenomenon, often requiring the concurrent application of antidepressant and analgesic drugs. Growing evidence suggests that the analgesic metamizole exhibits cytochrome P450 inducing properties. In the present study, we assessed the impact of metamizole and ibuprofen on plasma concentrations of the selective serotonin reuptake inhibitor sertraline. METHODS: Out of a therapeutic drug monitoring (TDM) database, three groups of patients were compared: patients receiving sertraline and metamizole (n = 15), patients receiving sertraline and ibuprofen (n = 19), and a matched control group without one of the analgesics (n = 19). RESULTS: Metamizole was associated with 67% lower median sertraline plasma concentrations compared to the control group (14 vs 42 ng/mL, P < 0.001). In contrast, differences between the ibuprofen group and the control group did not reach statistical significance (31 vs 42 ng/mL, P = 0.128). Moreover, the metamizole group demonstrated lower dose-adjusted drug concentrations than the ibuprofen group (0.10 vs 0.26 (ng/mL)/(mg/day), P = 0.008). Finally, the metamizole group exhibited a higher proportion of patients whose sertraline concentrations were below the therapeutic reference range (40% in the metamizole group, 5% in the ibuprofen group, 0% in the control group, P = 0.005) indicating therapeutically insufficient drug concentrations. CONCLUSION: Our findings support preliminary evidence that metamizole acts as a potent inductor of cytochrome P450 isoenzymes CYP2B6 and CYP3A4. We observed a clinically meaningful pharmacokinetic interaction between metamizole and sertraline, leading to insufficiently low sertraline drug concentrations. Clinicians should therefore consider alternative drug combinations or apply TDM-guided dose adjustment of sertraline.

Clinical response in patients treated with once-monthly paliperidone palmitate: analysis of a therapeutic drug monitoring (TDM) database.

To investigate pharmacokinetic correlates of clinical response in patients treated with once-monthly paliperidone palmitate (PP1M) injections at steady state. Plasma concentrations and dose-adjusted-plasma concentrations (C/D) of paliperidone from a naturalistic therapeutic drug monitoring (TDM) database were compared between responders and non-responders using the Clinical Global Impressions-Improvement scale (CGI-I) ratings. Analyses were based on the non-parametric Mann-Whitney U test and the Pearson Chi-squared test (χ2) with a significance level of 0.05. Subgroup analyses were performed separately in patients with schizophrenia spectrum, schizoaffective disorders and bipolar disorders. Comparing 93 responders with 80 non-responders, we detected no significant differences in the proportion of females, age, and body mass index (p's ranging 0.18-0.83); there were more smokers in the group of non-responders (p = 0.04), which also included more patients with bipolar disorders (p = 0.014). Despite the lack of differences for prescribed PP1M doses and dose intervals (p = 0.42 and p = 0.11, respectively), non-responders had higher paliperidone plasma concentrations and C/D levels (p = 0.033 and p = 0.021, respectively). Subgroup analyses did not yield differences for paliperidone plasma and C/D levels between non-responders and responders with schizophrenia spectrum (p = 0.099 and p = 0.14, respectively) and bipolar disorders (p = 0.95 and p = 0.75, respectively); dose-adjusted plasma concentrations were higher in non-responders compared to responders with schizoaffective disorders (p = 0.039), while no differences were reported for plasma levels (p = 0. 15). Our results show that paliperidone plasma concentrations over injection doses may be associated with patterns of clinical response suggesting potential utility of TDM as part of PP1M-based maintenance treatment.

Treatment Goals for Patients with Schizophrenia - A Narrative Review of Physician and Patient Perspectives.

INTRODUCTION: There are many possible treatment goals for patients with schizophrenia. Two major perspectives on treatment goals are the patient's and the physician's perspective. Patient-centered treatment mandates that an individual patient's treatment goals are taken into account when treatment is planned. In this narrative review, we address the commonalities and differences of the patient's and physician's perspectives. METHODS: We searched for literature on treatment goals for patients with schizophrenia from the last 10 years. RESULTS: Fifty-two relevant records were identified, 4 of which directly compare patient's and physician's perspectives. Two further articles used the same set of goals to ask patients or physicians for their assessment. DISCUSSION: Agreement between patients and physicians regarding valuation of treatment goals was high. However, physicians tended to put more emphasis on the classical "textbook" goals of symptom resolution and functioning, while patients stressed well-being and quality of life more. Results on treatment goals from patients are difficult to generalize, since recruiting representative patient samples is challenging and patient subgroups may have differing priorities.

Lack of Smoking Effects on Pharmacokinetics of Oral Paliperidone-analysis of a Naturalistic Therapeutic Drug Monitoring Sample.

INTRODUCTION: Major smoking effects have been reported for a series of psychotropic agents, mainly including substrates of CYP450 1A2, although smoking may also affect alternative metabolic pathways. To our knowledge, smoking effects on paliperidone pharmacokinetics have not been assessed yet. METHODS: We compared plasma concentrations of paliperidone as well as dose-corrected-plasma concentrations (C/D) from a naturalistic database between smokers and nonsmokers using nonparametrical tests, such as the Mann-Whitney U-test (MWU). Additionally, we compared light and heavy smokers with nonsmokers separately. RESULTS: Comparing 55 smokers with 37 nonsmokers treated with oral paliperidone, no differences in the percentage of females, age, body weight, body mass index, and daily paliperidone dose were reported (p=0.709 for χ2, p=0.26, p=0.38, p=0.67, and p=0.8 for MWU). No differences were detected in plasma concentrations or C/D values (p=0.50 and p=0.96 for MWU). Likewise, differences in daily dose, plasma concentrations, or C/D values were not significant between light smokers (n=17) and nonsmokers (p=0.61, p=0.81, and p=0.33 for MWU) or heavy smokers (n=22) and nonsmokers (p=0.874, p=0.38, and p=0.59; MWU in all cases). DISCUSSION: Paliperidone is not affected by smoking, and paliperidone dose-adjustments in smokers may not be necessary. This may be seen as an essential difference to risperidone, whose cytochrome-mediated metabolism might be affected by smoking.

Subtherapeutic bupropion and hydroxybupropion serum concentrations in a patient with CYP2C19*1/*17 genotype suggesting a rapid metabolizer status.

Bupropion is hydroxylated to its primary active metabolite hydroxybupropion by cytochrome P450 enzyme CYP2B6. In vitro data suggest the existence of alternative hydroxylation pathways mediated by the highly polymorphic enzyme CYP2C19. However, the impact of its genetic variants on bupropion metabolism in vivo is still under investigation. We report the case of a 28-year-old male Caucasian outpatient suffering from major depressive disorder who did not respond to a treatment with bupropion. Therapeutic drug monitoring revealed very low serum concentrations of both bupropion and hydroxybupropion. Genotyping identified a heterozygous status for the gain-of-function allele with the genotype CYP2C19*1/*17 predicting enhanced enzymatic activity. The present case shows a reduced bupropion efficacy, which may be explained by a reduced active moiety of bupropion and its active metabolite hydroxybupropion, due to alternative hydroxylation pathways mediated by CYP2C19 in an individual with CYP2C19 rapid metabolizer status. The case report thus illustrates the clinical relevance of therapeutic drug monitoring in combination with pharmacogenetics diagnostics for a personalized treatment approach.

Excretion of Antipsychotics Into the Amniotic Fluid, Umbilical Cord Blood, and Breast Milk: A Systematic Critical Review and Combined Analysis.

BACKGROUND: Antipsychotics are being increasingly prescribed during pregnancy and in the postpartum period. However, knowledge regarding the ability of antipsychotics to enter the fetal, newborn, and infant circulation presents inconsistencies. Evidence for penetration ratios in an array of matrices will contribute to further studies examining the mechanistic pathway from antipsychotic use to adverse events. METHODS: A systematic literature search of PubMed and EMBASE was performed to identify studies assessing the concentrations of antipsychotics in maternal blood (serum or plasma), amniotic fluid, umbilical cord blood, and/or breast milk. The penetration ratios were estimated by dividing the antipsychotic concentrations in the target matrix (ie, amniotic fluid, umbilical cord blood or breast milk) by the maternal concentration. Data are provided in means with ranges or SD depending on data availability. RESULTS: Forty-nine eligible studies were identified. For amniotic fluid, the penetration ratios were estimated for quetiapine, clozapine, and flupentixol, with quetiapine displaying the highest ratio (mean 0.59, range 0.09-1.70 versus 0.56, range 0.31-0.82 for clozapine and 0.24, range 0.23-0.24 for flupentixol). For umbilical cord blood, olanzapine had the highest ratio (mean 0.71 ± 0.42) followed by haloperidol (mean 0.66 ± 0.40) and paliperidone (mean 0.53, range 0.50-0.58). In case of breast milk, the highest ratio was observed for amisulpride (mean 14.42, range 11.86-19.50) followed by clozapine (mean 3.19, range 2.79-4.32) and haloperidol (mean 3.11, range 0.59-6.67). CONCLUSIONS: The ability of antipsychotics to enter the fetal, newborn, and infant circulation varies considerably among antipsychotics. Given sampling constraints of other matrices, measuring antipsychotic concentrations in maternal blood may represent the least expensive, most readily available, and reliable estimate of fetal/infant exposure.

The Effects of Co-prescription of Pantoprazole on the Clozapine Metabolism.

BACKGROUND: Polypharmacy including somatic medications such as proton pump inhibitors is a common phenomenon in psychiatric care. The aim of this study was to evaluate the pantoprazole effects on clozapine metabolism. METHODS: A large therapeutic drug-monitoring database containing plasma concentrations of CLZ was analyzed. The results were stratified into four groups: a non-smoking (n=250) and a smoking group (n=326), and two groups co-medicated with pantoprazole: non-smokers (n=26) and smokers (n=29). The analysis was based on the non-parametrical Mann-Whitney U test (M-W-U) with a significance level of 0.05. RESULTS: Differences reached statistical significance for pharmacokinetic parameters between CLZ monotherapy and co-medication with pantoprazole neither in smokers nor in non-smokers (p>0.05 for M-W-U in pairwise comparisons). In patients with clozapine monotherapy, smokers had a higher daily dosage of CLZ compared to non-smokers (mean dosage 363±181 vs. 291±145 mg/day, p<0.001 for M-W-U). CONCLUSIONS: Adding pantoprazole to an ongoing treatment with clozapine does not alter the metabolism of clozapine to a significant extent.

Dopamine D2 Receptor Occupancy Estimated From Plasma Concentrations of Four Different Antipsychotics and the Subjective Experience of Physical and Mental Well-Being in Schizophrenia: Results From the Randomized NeSSy Trial.

BACKGROUND: Impaired subjective well-being in schizophrenia patients treated with antipsychotics has often been linked inter alia to the antidopaminergic effects of medication. Thus, it is important to capture the association between striatal dopamine D2 receptor occupancy (D2-RO) and global subjective well-being. We examined this association using data from our multicenter, randomized, double-blind Neuroleptic Strategy Study (NeSSy). METHODS: An innovative double randomization process was used for allocation of patients to the specific treatment groups. Plasma drug concentrations were measured after 6 and 24 weeks of treatment to obtain the estimated D2-RO (eD2-RO) relative to literature values. We made an exploratory analysis of associations between eD2-RO and subjective well-being scores. One hundred two blood samples from 69 patients were available for the analysis. Because of the lack of a satisfactory occupancy model for quetiapine, only haloperidol, flupentixol, and olanzapine treatment groups were pooled, whereas aripiprazole data were analyzed separately, because of its partial agonistic properties. RESULTS: In the pooled antagonist group, eD2-RO correlated negatively with the summarized well-being score. In a more detailed analysis, this association could be confirmed for all first-generation antipsychotic-treated patients, but not for the separate second-generation antipsychotic groups. In the aripiprazole group, higher eD2-RO was associated with impaired physical well-being, but had no association with mental well-being. CONCLUSIONS: Our results suggest that high plasma levels and consequently high occupancy at D2 receptors are disadvantageous for subjective well-being, as distinct from the objective extrapyramidal side effects. To minimize patients' malaise, which disfavors adherence, implementation of therapeutic drug monitoring in the clinical routine may be useful.

Pharmacokinetics of venlafaxine in treatment responders and non-responders: a retrospective analysis of a large naturalistic database.

PURPOSE: To assess in a large naturalistic sample, whether clinical response to a treatment with venlafaxine is associated with different patterns of plasma concentrations of active moiety, AM (sum of venlafaxine (VEN) and its active metabolite O-desmethylvenlafaxine (ODVEN)). METHODS: Applying a regression model, plasma concentrations and plasma concentrations corrected-by-dosage (C/D) for AM were included as independent variable with Clinical Global Impressions-Improvement (CGI-I) scale ratings as dependent variable. Moreover, AM, VEN, and ODVEN were compared between treatment responders and non-responders, defining response as much or very much improved on the CGI-I scale based on the non-parametric Mann-Whitney U (M-W-U) test with a significance level of 0.05. RESULTS: No correlations were found between AM and C/D AM plasma concentrations and CGI-I ratings (regression coefficient 0.0, CI 0.000, 0.001, p = 0.492 for AM and 0.047, CI - 0.065, 0.159, p = 0.408 for C/D AM). Venlafaxine daily dosage did not differ between responders and non-responders (217.7 ± 76.9 vs. 222.0 ± 72.7 mg/day, p = 0.45 for M-W-U). Responders displayed lower ODVEN (p = 0.033) and AM (p = 0.031) plasma concentrations than non-responders (p = 0.033 and 0.031, respectively for M-W-U). No other differences were detected. Using a cut-off level of 400 ng/mL for AM concentrations, a higher percentage of responders was reported in the group of patients with AM < 400 ng/mL (13.04%) compared to patients with AM > 400 ng/mL (8%) (p = 0.038). CONCLUSIONS: Higher ODVEN and AM concentrations in non-responders than in responders indicate that treatment escalation above upper thresholds of therapeutic reference ranges of venlafaxine is not promising. Hence, the therapeutic reference range for venlafaxine can help in improving outcomes in a measurement-based care model that takes advantage of therapeutic drug monitoring.

Pharmacokinetic correlates of venlafaxine: associated adverse reactions.

To address the potential correlation between plasma concentrations of venlafaxine (VEN), its active metabolite O-desmethylvenlafaxine (ODVEN) and the active moiety, AM, (ODVEN + VEN) and adverse drug reactions (ADR) in a large naturalistic sample of in- and outpatients. We compared plasma concentrations of VEN, ODVEN and AM and dose-adjusted (C/D) levels as well the ODVEN/VEN ratios between patients complaining ADRs, following the Udvalg for Kliniske Undersogelser side effect rating scales (UKU) (n = 114) and patients without ADRs (control group, n = 688) out of a naturalistic database. We also investigated potential pharmacokinetic correlates of the four UKU categories by comparing patients complaining ADRs with those who did not. Based on previous literature we applied different ODVEN/VEN ratio values as cut-offs to split our sample into two groups at a time and compare frequencies of ADRs between the groups. No differences for demographic and pharmacokinetic variables including plasma and C/D concentrations as well as ODVEN/VEN ratios were observed between study groups. Neither the comparisons between females and males nor between elderly and non-elderly patients revealed significant differences (p > 0.05 in all cases). No differences were also reported exploring the patients complaining ADRs from the 4 UKU categories separately. After applying various ODVEN/VEN cut-offs, groups did not display differences in frequencies of ADRs (p > 0.05 in all cases). Our findings do not demonstrate a direct link between venlafaxine metabolism measures and ADRs. Therefore, additional dimensions are needed to be considered in future trials aiming to disentangle the involved aspects of ADRs in patients receiving venlafaxine.

Antidepressants in breast milk; comparative analysis of excretion ratios.

Despite increasing prescription rates of antidepressants in pregnant and breastfeeding women over the past decades, evidence of drug exposure for neonates through lactation is very sparse. Concentrations of three antidepressants citalopram, sertraline, and venlafaxine were measured in maternal blood and breast milk in 17 women receiving antidepressant therapy during breastfeeding period. We also computed concentration-by-dose-ratios (C/D) and milk to serum (plasma) penetration ratios (M/P). Non-parametric tests were applied. Serum concentration of citalopram and daily dosage correlated positively while daily dosage and mother milk concentration did not (rho = 0.939, p = 0.005, and rho = 0.772, p > 0.05 respectively). A significant correlation was also found between serum and milk concentrations (rho = 0.812, p = 0.05). Venlafaxine daily dosage correlated positively with the active moiety milk concentration (rho = 0.949, p = 0.014). No significant correlations were reported for sertraline. The amount of antidepressant concentrations to which neonates may be exposed, assessed as absolute infant dose (AID), was particularly low with the highest median AID being 0.16 mg/kg/day for venlafaxine. No significant difference was detected for the M/P ratios between different drugs (p > 0.05), whereas the comparison of C/D ratios revealed lower values in the sertraline group, with the highest values reported for citalopram group (p = 0.007 for serum concentrations and p = 0.008 for mother milk). Findings suggest that breastfeeding under antidepressant treatment constantly exposes children with measurable drug concentrations. As daily dosage and serum concentration of the antidepressants did not predict drug concentrations in mother milk, measuring of drug concentrations in milk helps to quantify drug exposure during breastfeeding. More data-even data of drug concentrations in breastfed children-are needed to better assess the effects of drug exposure on children's development.

[Therapeutic drug monitoring in neuropsychopharmacology : Summary of the consensus guidelines 2017 of the TDM task force of the AGNP]. / Therapeutisches Drug-Monitoring in der Neuropsychopharmakologie : Zusammenfassung der Konsensusleitlinien 2017 der TDM-Arbeitsgruppe der AGNP.

Therapeutic drug monitoring (TDM) is the quantification and interpretation of drug concentrations in blood serum or plasma to optimize pharmacological therapy. TDM is an instrument with which the high interindividual variability of pharmacokinetics of patients can be identified and therefore enables a personalized pharmacotherapy. In September 2017 the TDM task force of the Working Group for Neuropsychopharmacology and Pharmacopsychiatry (AGNP) published an update of the consensus guidelines on TDM published in 2011. This article summarizes the essential statements for the clinical practice in psychiatry and neurology.

How to Treat Hypertension in Venlafaxine-Medicated Patients-Pharmacokinetic Considerations in Prescribing Amlodipine and Ramipril.

BACKGROUND: Amlodipine (AMLO) and ramipril (RAMI) belong to the most prescribed drugs in patients with hypertension, a condition also encountered in depression. Venlafaxine may worsen hypertension because of noradrenergic properties. Although of special clinical relevance, data on pharmacokinetic interactions between AMLO, RAMI, and venlafaxine (VEN) are lacking. METHODS: Two TDM databases consisting of plasma concentrations of VEN and its active metabolite O-desmethylvenlafaxine (ODVEN) were analyzed. We considered a group of patients comedicated with AMLO, VAMLO (n = 22); a group comedicated with RAMI, VRAMI (n = 20); and a 4:1 control group age matched to the VAMLO group receiving VEN without confounding medications, V0 (n = 88). Plasma concentrations of VEN, ODVEN, and active moiety, AM (VEN + ODVEN); metabolic ratio (ODVEN/VEN); and dose-adjusted plasma concentrations (C/D) were compared using nonparametric tests. RESULTS: Groups did not differ in daily VEN dose, age, or sex. The metabolic ratio (ODVEN/VEN) was lower in the AMLO group (P = 0.029), whereas the RAMI group showed lower values for ODVEN (P = 0.029). All other parameters showed no significant differences. CONCLUSIONS: Significantly lower values for the metabolic ratio in the AMLO group are unlikely to be explained by cytochrome P450 (CYP) 3A4 and weak CYP2D6 inhibition by AMLO. Other factors such as differences in CYP2D6 polymorphisms and metabolizer status may better explain the findings. Ramipril showed modest effects with changes in ODVEN concentrations that did not remain significant after dose-adjusted comparisons.