PET/CT study of dopamine transporter (DAT) binding with the triple reuptake inhibitor toludesvenlafaxine in rats and humans.

PURPOSE: Toludesvenlafaxine is a recently developed antidepressant that belongs to the triple reuptake inhibitor class. Despite the in vitro evidence that toludesvenlafaxine inhibits the reuptake of serotonin (5-HT), norepinephrine (NE) and dopamine (DA), there is no in vivo evidence that toludesvenlafaxine binds to DAT and increases DA level, a mechanism thought to contribute to its favorable clinical performance. METHODS: Positron emission tomography/computed tomography (PET/CT) was used to examine the DAT binding capacity in healthy rats and human subjects and microdialysis was used to examine the striatal DA level in rats. [18F]FECNT and [11C]CFT were used as PET/CT radioactive tracer for rat and human studies, respectively. RESULTS: In rats, 9 mg/kg of toludesvenlafaxine hydrochloride (i.v.) followed by an infusion of 3 mg/kg via minipump led to the binding rate to striatum DAT at 3.7 - 32.41% and to hypothalamus DAT at 5.91 - 17.52% during the 45 min scanning period. 32 mg/kg oral administration with toludesvenlafaxine hydrochloride significantly increased the striatal DA level with the AUC0 - 180 min increased by 63.9%. In healthy volunteers, 160 mg daily toludesvenlafaxine hydrochloride sustained-release tablets for 4 days led to an average occupancy rates of DAT at 8.04% ± 7.75% and 8.09% ± 7.00%, respectively, in basal ganglion 6 h and 10 h postdose. CONCLUSION: These results represent the first to confirm the binding of toludesvenlafaxine to DAT in both rats and humans using PET/CT, and its elevation of brain DA level, which may help understand the unique pharmacological and functional effects of triple reuptake inhibitors such as toludesvenlafaxine. GOV IDENTIFIERS: NCT05905120. Registered 14 June 2023. (retrospectively registered).

Antidepressants for the treatment of adults with major depressive disorder in the maintenance phase: a systematic review and network meta-analysis.

A systematic review and random-effects model network meta-analysis were conducted to compare the efficacy, acceptability, tolerability, and safety of antidepressants to treat adults with major depressive disorder (MDD) in the maintenance phase. This study searched the PubMed, Cochrane Library, and Embase databases and included only double-blind, randomized, placebo-controlled trials with an enrichment design: patients were stabilized on the antidepressant of interest during the open-label study and then randomized to receive the same antidepressant or placebo. The outcomes were the 6-month relapse rate (primary outcome, efficacy), all-cause discontinuation (acceptability), discontinuation due to adverse events (tolerability), and the incidence of individual adverse events. The risk ratio with a 95% credible interval was calculated. The meta-analysis comprised 34 studies (n = 9384, mean age = 43.80 years, and %females = 68.10%) on 20 antidepressants (agomelatine, amitriptyline, bupropion, citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, levomilnacipran, milnacipran, mirtazapine, nefazodone, paroxetine, reboxetine, sertraline, tianeptine, venlafaxine, vilazodone, and vortioxetine) and a placebo. In terms of the 6-month relapse rate, amitriptyline, citalopram, desvenlafaxine, duloxetine, fluoxetine, fluvoxamine, mirtazapine, nefazodone, paroxetine, reboxetine, sertraline, tianeptine, venlafaxine, and vortioxetine outperformed placebo. Compared to placebo, desvenlafaxine, paroxetine, sertraline, venlafaxine, and vortioxetine had lower all-cause discontinuation; however, sertraline had a higher discontinuation rate due to adverse events. Compared to placebo, venlafaxine was associated with a lower incidence of dizziness, while desvenlafaxine, sertraline, and vortioxetine were associated with a higher incidence of nausea/vomiting. In conclusion, desvenlafaxine, paroxetine, venlafaxine, and vortioxetine had reasonable efficacy, acceptability, and tolerability in the treatment of adults with stable MDD.

Physiologically Based Pharmacokinetic Modeling to Unravel the Drug-gene Interactions of Venlafaxine: Based on Activity Score-dependent Metabolism by CYP2D6 and CYP2C19 Polymorphisms.

BACKGROUND: Venlafaxine (VEN) is a commonly utilized medication for alleviating depression and anxiety disorders. The presence of genetic polymorphisms gives rise to considerable variations in plasma concentrations across different phenotypes. This divergence in phenotypic responses leads to notable differences in both the efficacy and tolerance of the drug. PURPOSE: A physiologically based pharmacokinetic (PBPK) model for VEN and its metabolite O-desmethylvenlafaxine (ODV) to predict the impact of CYP2D6 and CYP2C19 gene polymorphisms on VEN pharmacokinetics (PK). METHODS: The parent-metabolite PBPK models for VEN and ODV were developed using PK-Sim® and MoBi®. Leveraging prior research, derived and implemented CYP2D6 and CYP2C19 activity score (AS)-dependent metabolism to simulate exposure in the drug-gene interactions (DGIs) scenarios. The model's performance was evaluated by comparing predicted and observed values of plasma concentration-time (PCT) curves and PK parameters values. RESULTS: In the base models, 91.1%, 94.8%, and 94.6% of the predicted plasma concentrations for VEN, ODV, and VEN + ODV, respectively, fell within a twofold error range of the corresponding observed concentrations. For DGI scenarios, these values were 81.4% and 85% for VEN and ODV, respectively. Comparing CYP2D6 AS = 2 (normal metabolizers, NM) populations to AS = 0 (poor metabolizers, PM), 0.25, 0.5, 0.75, 1.0 (intermediate metabolizers, IM), 1.25, 1.5 (NM), and 3.0 (ultrarapid metabolizers, UM) populations in CYP2C19 AS = 2.0 group, the predicted DGI AUC0-96 h ratios for VEN were 3.65, 3.09, 2.60, 2.18, 1.84, 1.56, 1.34, 0.61, and for ODV, they were 0.17, 0.35, 0.51, 0.64, 0.75, 0.83, 0.90, 1.11, and the results were similar in other CYP2C19 groups. It should be noted that PK differences in CYP2C19 phenotypes were not similar across different CYP2D6 groups. CONCLUSIONS: In clinical practice, the impact of genotyping on the in vivo disposition process of VEN should be considered to ensure the safety and efficacy of treatment.

A Massive Venlafaxine Intoxication: Evolution of Cardiac Toxicity with Venlafaxine and O-Desmethylvenlafaxine Elimination Kinetics: A Grand Round.

BACKGROUND: This study presents the case of a 19-year-old woman who attempted suicide by ingesting 11.25 g of venlafaxine (V). She was admitted to the hospital with severe biventricular dysfunction, progressing to cardiac arrest requiring extracorporeal circulatory life support for 11 days. The pharmacokinetics of venlafaxine during impaired cardiac output and the effect of its active metabolite, the O-desmethylvenlafaxine (ODV), are currently not very well understood. METHODS AND RESULTS: Serum concentrations of V and ODV were monitored twice daily for 3 weeks. The maximum concentrations of venlafaxine and ODV were at 14 hours after ingestion, with 29,180 mcg/L for V and 5399 mcg/L for ODV. Half-lives increased, requiring 2 weeks to eliminate the drug. The left ventricular ejection fraction significantly improved when V + ODV was below 1000 mcg/L and remained altered until the ODV concentrations were lower than 400 mcg/L. CONCLUSIONS: This report, with complete elimination kinetic of V and ODV in a monodrug intoxication, provides information about the modification of pharmacokinetics in the case of an overdose managed by extracorporeal circulatory life support, the cardiac toxicity of ODV, and the value of the toxic threshold for the active moiety.

Effectiveness of Antidepressants in Combination with Psychotherapy.

BACKGROUND: Consensus-guidelines for prescribing antidepressants recommend that clinicians should be vigilant to match antidepressants to patient's medical history but provide no specific advice on which antidepressant is best for a given medical history. AIMS OF THE STUDY: For patients with major depression who are in psychotherapy, this study provides an empirically derived guideline for prescribing antidepressant medications that fit patients' medical history. METHODS: This retrospective, observational, cohort study analyzed a large insurance database of 3,678,082 patients. Data was obtained from healthcare providers in the U.S. between January 1, 2001, and December 31, 2018. These patients had 10,221,145 episodes of antidepressant treatments. This study reports the remission rates for the 14 most commonly prescribed single antidepressants (amitriptyline, bupropion, citalopram, desvenlafaxine, doxepin, duloxetine, escitalopram, fluoxetine, mirtazapine, nortriptyline, paroxetine, sertraline, trazodone, and venlafaxine) and a category named "Other" (other antidepressants/combination of antidepressants). The study used robust LASSO regressions to identify factors that affected remission rate and clinicians' selection of antidepressants. The selection bias in observational data was removed through stratification. We organized the data into 16,770 subgroups, of at least 100 cases, using the combination of the largest factors that affected remission and selection bias. This paper reports on 2,467 subgroups of patients who had received psychotherapy. RESULTS: We found large, and statistically significant, differences in remission rates within subgroups of patients. Remission rates for sertraline ranged from 4.5% to 77.86%, for fluoxetine from 2.86% to 77.78%, for venlafaxine from 5.07% to 76.44%, for bupropion from 0.5% to 64.63%, for desvenlafaxine from 1.59% to 75%, for duloxetine from 3.77% to 75%, for paroxetine from 6.48% to 68.79%, for escitalopram from 1.85% to 65%, and for citalopram from 4.67% to 76.23%. Clearly these medications are ideal for patients in some subgroups but not others. If patients are matched to the subgroups, clinicians can prescribe the medication that works best in the subgroup. Some medications (amitriptyline, doxepin, nortriptyline, and trazodone) always had remission rates below 11% and therefore were not suitable as single antidepressant therapy for any of the subgroups. DISCUSSIONS: This study provides an opportunity for clinicians to identify an optimal antidepressant for their patients, before they engage in repeated trials of antidepressants. IMPLICATIONS FOR HEALTH CARE PROVISION AND USE: To facilitate the matching of patients to the most effective antidepressants, this study provides access to a free, non-commercial, decision aid at http://MeAgainMeds.com. IMPLICATIONS FOR HEALTH POLICIES:  Policymakers should evaluate how study findings can be made available through fragmented electronic health records at point-of-care. Alternatively, policymakers can put in place an AI system that recommends antidepressants to patients online, at home, and encourages them to bring the recommendation to their clinicians at their next visit. IMPLICATIONS FOR FURTHER RESEARCH:  Future research could investigate (i) the effectiveness of our recommendations in changing clinical practice, (ii) increasing remission of depression symptoms, and (iii) reducing cost of care. These studies need to be prospective but pragmatic. It is unlikely random clinical trials can address the large number of factors that affect remission.

Novel radioiodinated desvenlafaxine-loaded lipid nanocapsule for brain delivery.

Lipid nanocapsules (LNCs) are lipid nanocarriers developed for drug delivery enhancement. The antidepressant drug desvenlafaxine (DSV) was entrapped in LNC to improve its brain delivery. Different DSV-loaded LNCs formulae using different oils and surfactants were studied to obtain the optimum formula for further studies. In vivo biodistribution studies were done using Swiss albino mice by intravenous injection of DSV-loaded LNCs by radioiodination technique. The optimum DSV-loaded LNC formula was obtained by using Labrafil® M1944CS as the oil and Solutol® HS15 as the surfactant in the ratio of 1:1, with a particle size of 34.28 ± 0.41 nm, a polydispersity index of 0.032 ± 0.05, a zeta potential of -25.77 ± 1.41, and good stability for up to 6 months. The in vivo biodistribution and pharmacokinetics data ensure the bioavailability improvement for DSV brain delivery as Cmax and AUC(1-t) increased more than double for intravenously DSV-loaded LNCs compared with the DSV solution. In conclusion, the results obtained from this study give an insight into the great potential of using DSV-loaded LNC for the enhancement of brain delivery.

Intranasal bilosomes in thermosensitive hydrogel: advancing desvenlafaxine succinate delivery for depression management.

Depression, the second biggest cause of disability worldwide, is widespread. Many antidepressant medications, including Desvenlafaxine Succinate (D.V.S.), function by elevating neurotransmitter levels at the synapse through the inhibition of reabsorption by neurons. However, the effectiveness of these treatments is often limited by their inability to reach the brain using conventional administration methods. Bilosome-stabilized nanovesicles containing bile salts have drawn much interest because of their adaptability and versatility in various applications. This study aimed to address this issue by formulating intranasal bilosomes incorporated into a mucoadhesive in situ gel to deliver D.V.S. directly to the brain for depression treatment. The desvenlafaxine-loaded bilosomes were developed using a thin film hydration method based on the l-optimal design. They were intended to provide a more convenient route of administration for antidepressants, enhancing bioavailability and brain targeting through intranasal delivery. The study assessed the optimized bilosomes for particle size (311.21 ± 0.42 nm), Zeta potential (-37.35 ± 0.43)and encapsulation efficiency (99.53 ± 0.41%) and further evaluated them in ex vivo and in vivo pharmacokinetics studies. Pharmacokinetic data reveal enhanced brain uptake compared to a free drug. A statistically optimized bilosome formulation was determined. The intranasal administration of mucoadhesive in situ gel containing desvenlafaxine succinate-loaded bilosomes facilitated direct nose-to-brain drug delivery, improving brain bioavailability.

Photocatalytic Degradation of Inherent Pharmaceutical Concentration Levels in Real Hospital WWTP Effluents Using g-C3N4 Catalyst on CPC Pilot Scale Reactor.

The objective of this work was to evaluate the efficiency of a solar photocatalytic process using g-C3N4 as photocatalyst on the degradation of pharmaceutical compounds detected in hospital wastewater treatment plant secondary effluents. A compound parabolic collector pilot plant, established in the secondary effluent stream of the Ioannina city hospital wastewater treatment plant, was used for the photocatalytic experiments. The analysis of the samples before and after the photocatalytic treatment was accomplished using solid phase extraction (SPE), followed by UHPLC-LTQ/Orbitrap HRMS. Initial effluent characterization revealed the presence of ten pharmaceutical compounds. Among these, amisulpride, O-desmethyl venlafaxine, venlafaxine and carbamazepine were detected in all experiments. Initial concentrations ranged from 73 ng L-1 for citalopram to 2924.53 ng L-1 for O-desmethyl venlafaxine. The evolution of BOD5 and COD values were determined before and after the photocatalytic treatment. All detected pharmaceuticals were removed in percentages higher than 54% at an optimum catalyst loading ranging between 200 and 300 mg L-1. The potential of the catalyst to be reused without any treatment for two consecutive cycles was studied, showing a significant efficiency decrease.

Comparison of UV and UV-LED activated sodium percarbonate for the degradation of O-desmethylvenlafaxine.

As an active metabolite of venlafaxine and emerging antidepressant, O-desmethylvenlafaxine (ODVEN) was widely detected in different water bodies, which caused potential harm to human health and environmental safety. In this study, the comparative work on the ODVEN degradation by UV (254 nm) and UV-LED (275 nm) activated sodium percarbonate (SPC) systems was systematically performed. The higher removal rate of ODVEN can be achieved under UV-LED direct photolysis (14.99%) than UV direct photolysis (4.57%) due to the higher values of photolysis coefficient at the wavelength 275 nm. Significant synergistic effects were observed in the UV/SPC (80.38%) and UV-LED/SPC (53.57%) systems and the former exhibited better performance for the elimination of ODVEN. The degradation of ODVEN all followed the pseudo-first-order kinetics well in these processes, and the pseudo-first-order rate constant (kobs) increased with increasing SPC concentration. Radicals quenching experiments demonstrated that both ·OH and CO3·- were involved in the degradation of ODVEN and the second-order rate constant of ODVEN with CO3·- (1.58 × 108 (mol/L)-1 sec-1) was reported for the first time based on competitive kinetic method. The introduction of HA, Cl-, NO3- and HCO3- inhibited the ODVEN degradation to varying degrees in the both processes. According to quantum chemical calculation, radical addition at the ortho-position of the phenolic hydroxyl group was confirmed to be the main reaction pathways for the oxidation of ODVEN by ·OH. In addition, the oxidation of ODVEN may involve the demethylation, H-abstraction, OH-addition and C-N bond cleavage. Eventually, the UV-LED/SPC process was considered to be more cost-effective compared to the UV/SPC process, although the UV/SPC process possessed a higher removal rate of ODVEN.

Impact of maternal desvenlafaxine exposure on brain development in pregnant albino rats and their fetuses.

Depression during pregnancy adversely affects fetal development. Desvenlafaxine drug is used for the treatment of gestational depression. In light of the well-established role of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in regulating neurogenesis and neural survival, the role of S100b in nerve cell energetic metabolism, differentiation of neurons and glial cells, an aberrant increase in NGF, BDNF and S100b expression in the fetal brain may contribute to desvenlafaxine cognitive disorders by altering brain development. This study is trying to determine the effect of desvenlafaxine on brain development. Thirty timed pregnant rats (from the 5th to the 20th day) were divided into three groups: control, low dose (5.14 mg/kg/day) and high dose (10.28 mg/kg/day) of desvenlafaxine where all animals received the corresponding doses by gavage. Maternal and fetal brain samples were fixed for histological, immunohistochemical (IHC) study of NGF and evaluated for BDNF and S100b genes expression. Desvenlafaxine induced some of the histopathological alterations in maternal and fetal rat brains. Moreover, IHC analysis of maternal and fetal rat brains showed that groups treated with desvenlafaxine demonstrated a significant increase of NGF protein immunoreactivity compared with that in the controls. Gene expression results revealed upregulation of messenger RNA BDNF and S100B expression. According to developmental changes in the brain, desvenlafaxine affects neonatal growth during pregnancy, which may lead to delay of brain development. So, it is essential to survey the roles of antidepressant drugs on neonatal development during pregnancy.

Using Machine Learning to Predict Remission in Patients With Major Depressive Disorder Treated With Desvenlafaxine.

BACKGROUND: Major depressive disorder (MDD) is a common and burdensome condition that has low rates of treatment success for each individual treatment. This means that many patients require several medication switches to achieve remission; selecting an effective antidepressant is typically a sequential trial-and-error process. Machine learning techniques may be able to learn models that can predict whether a specific patient will respond to a given treatment, before it is administered. This study uses baseline clinical data to create a machine-learned model that accurately predicts remission status for a patient after desvenlafaxine (DVS) treatment. METHODS: We applied machine learning algorithms to data from 3,399 MDD patients (90% of the 3,776 subjects in 11 phase-III/IV clinical trials, each described using 92 features), to produce a model that uses 26 of these features to predict symptom remission, defined as an 8-week Hamilton Depression Rating Scale score of 7 or below. We evaluated that learned model on the remaining held-out 10% of the data (n = 377). RESULTS: Our resulting classifier, a trained linear support vector machine, had a holdout set accuracy of 69.0%, significantly greater than the probability of classifying a patient correctly by chance. We demonstrate that this learning process is stable by repeatedly sampling part of the training dataset and running the learner on this sample, then evaluating the learned model on the held-out instances of the training set; these runs had an average accuracy of 67.0% ± 1.8%. CONCLUSIONS: Our model, based on 26 clinical features, proved sufficient to predict DVS remission significantly better than chance. This may allow more accurate use of DVS without waiting 8 weeks to determine treatment outcome, and may serve as a first step toward changing psychiatric care by incorporating clinical assistive technologies using machine-learned models.

Measurement of Hepatic CYP3A4 and 2D6 Activity Using Radioiodine-Labeled O-Desmethylvenlafaxine.

Drug metabolizing enzyme activity is affected by various factors such as drug-drug interactions, and a method to quantify drug metabolizing enzyme activity in real time is needed. In this study, we developed a novel radiopharmaceutical for quantitative imaging to estimate hepatic CYP3A4 and CYP2D6 activity. Iodine-123- and 125-labeled O-desmethylvenlafaxine (123/125I-ODV) was obtained with high labeling and purity, and its metabolism was found to strongly involve CYP3A4 and CYP2D6. SPECT imaging in normal mice showed that the administered 123I-ODV accumulated early in the liver and was excreted into the gallbladder, as evaluated by time activity curves. In its biological distribution, 125I-ODV administered to mice accumulated early in the liver, and only the metabolite of 125I-ODV was quickly excreted into the bile. In CYP3A4- and CYP2D6-inhibited model mice, the accumulation in bile decreased more than in normal mice, indicating inhibition of metabolite production. These results indicated that imaging and quantifying the accumulation of radioactive metabolites in excretory organs will aid in determining the dosages of various drugs metabolized by CYP3A4 and CYP2D6 for individualized medicine. Thus, 123/125I-ODV has the potential to direct, comprehensive detection and measurement of hepatic CYP3A4 and CYP2D6 activity by a simple and less invasive approach.

The network structure of core depressive symptom-domains in major depressive disorder following antidepressant treatment: a randomized clinical trial.

BACKGROUND: Network analysis (NA) conceptualizes psychiatric disorders as complex dynamic systems of mutually interacting symptoms. Major depressive disorder (MDD) is a heterogeneous clinical condition, and very few studies to date have assessed putative changes in its psychopathological network structure in response to antidepressant (AD) treatment. METHODS: In this randomized trial with adult depressed outpatients (n = 151), we estimated Gaussian graphical models among nine core MDD symptom-domains before and after 8 weeks of treatment with either escitalopram or desvenlafaxine. Networks were examined with the measures of cross-sectional and longitudinal structure and connectivity, centrality and predictability as well as stability and accuracy. RESULTS: At baseline, the most connected MDD symptom-domains were fatigue-cognitive disturbance, whereas at week 8 they were depressed mood-suicidality. Overall, the most central MDD symptom-domains at baseline and week 8 were, respectively, fatigue and depressed mood; in contrast, the most peripheral symptom-domain across both timepoints was appetite/weight disturbance. Furthermore, the psychopathological network at week 8 was significantly more interconnected than at baseline, and they were also structurally dissimilar. CONCLUSION: Our findings highlight the utility of focusing on the dynamic interaction between depressive symptoms to better understand how the treatment with ADs unfolds over time. In addition, depressed mood, fatigue, and cognitive/psychomotor disturbance seem to be central MDD symptoms that may be viable targets for novel, focused therapeutic interventions.

Trajectories of Function and Symptom Change in Desvenlafaxine Clinical Trials: Toward Personalized Treatment for Depression.

PURPOSE/BACKGROUND: Heterogeneity has been documented in trajectories of symptom change during antidepressant treatment for major depressive disorder (MDD). It is unclear whether distinct trajectories of change exist for functioning during antidepressant treatment. METHODS/PROCEDURES: This analysis explored distinct trajectories of functioning in MDD and tested whether they corresponded to trajectories of symptom change. Data were from 4317 patients and were pooled from 9 randomized placebo-controlled trials. Growth mixture modeling was used to identify trajectories of Hamilton Rating Scale for Depression (HRSD) and Sheehan Disability Scale (SDS) for placebo- and desvenlafaxine-treated patients. FINDINGS/RESULTS: Three trajectories were identified for symptoms (HRSD) in patients receiving placebo (mean reduction baseline to week 8, -18.4 [most favorable] to -2.6 points [least favorable]). Four HRSD trajectories were identified for patients receiving desvenlafaxine (mean reduction from baseline to week 8, -17.2 [most favorable] to -2.6 points [least favorable]). Four trajectories were identified for functioning (SDS) in patients receiving placebo (mean reduction baseline to week 8, -13.6 [most favorable] to -0.8 points [least favorable]), and 3 for desvenlafaxine (-12.8 to -1.4 points, respectively). Percentages of agreement between most favorable HRSD and SDS trajectories were 75% (placebo) and 85% (desvenlafaxine), and for least favorable trajectories were 88% (placebo) and 80% (desvenlafaxine). IMPLICATIONS/CONCLUSIONS: Distinct trajectories of change based on symptoms and functioning were identified among patients with MDD receiving desvenlafaxine and among patients with MDD receiving placebo. Differentiating subpopulations of patients has the potential to provide a more personalized treatment of patients with MDD.ClinicalTrials.govIdentifiers: NCT00072774; NCT00277823; NCT00300378; NCT00384033; NCT00798707; NCT00863798; NCT01121484; NCT00824291; NCT01432457.

Dose-Dependent Inhibition of CYP2D6 by Bupropion in Patients With Depression.

PURPOSE: The aim of this study was to investigate the potential dose-dependent CYP2D6 inhibition by bupropion (BUP) in patients with depression. METHODS: Patients combining BUP with venlafaxine were included from a therapeutic drug monitoring (TDM) database at the Diakonhjemmet Hospital (Oslo, Norway). The O/N-desmethylvenlafaxine metabolic ratio measured in TDM samples was used as a biomarker for CYP2D6 phenotype and was compared between patients treated with BUP 150 mg/d and 300 mg/d or greater. In addition, reference groups of venlafaxine-treated patients genotyped as CYP2D6 poor metabolizers (PMs, no CYP2D6 activity) and normal metabolizers (NMs, fully functional CYP2D6 activity) were included. FINDINGS: A total of 221 patients were included in the study. The median O/N-desmethylvenlafaxine metabolic ratio was significantly higher in patients treated with BUP 150 mg/d (n = 59) versus 300 mg/d or greater (n = 34, 1.77 vs 0.96, P < 0.001). In CYP2D6 NMs (n = 62) and PMs (n = 66), the median metabolic ratios were 40.55 and 0.48, respectively. For patients treated with BUP 150 mg/d, 11 (19%) of the 59 patients were phenoconverted to PMs, whereas this was the case for 17 (50%) of the 34 patients treated with BUP 300 mg/d or greater. CONCLUSIONS: Bupropion exhibits a clear dose-dependent CYP2D6 inhibitory effect during treatment of patients with depression. This finding is of clinical relevance when adjusting dosing of CYP2D6 substrates during comedication with BUP. Half of the patients treated with high-dose BUP are converted to CYP2D6 PM phenotype. Because of the variability in CYP2D6 inhibition, TDM of CYP2D6 substrates should be considered to provide individualized dose adjustments during comedication with BUP.

Effects of CYP2D6 Genotypes on Venlafaxine Metabolism in Japanese Psychiatric Patients With Depression.

BACKGROUND: Venlafaxine (VEN) is primarily metabolized by CYP2D6. Although several studies have reported the significant effects of CYP2D6 on VEN and O-desmethylvenlafaxine (ODV) pharmacokinetics in Whites, limited data are available regarding the effects of the Asian-specific CYP2D6 genotype on VEN metabolism. This study evaluated the effects of the CYP2D6*10 and CYP2D6*5 genotypes on the steady-state plasma concentrations of VEN and ODV in Japanese patients. METHODS: This study included 75 Japanese patients with depression who were treated with VEN. Steady-state plasma concentrations of VEN and ODV were measured using liquid chromatography. Polymerase chain reaction was used to determine CYP2D6 genotypes. A stepwise multiple regression analysis was performed to analyze the relationship between independent variables (sex, age, smoking habit, and number of mutated alleles, CYP2D6*10 and CYP2D6*5), subject-dependent variables (plasma concentrations of VEN and ODV [all corrected for dose and body weight]), and the ODV/VEN ratio. RESULTS: Significant correlations were observed between the daily dose of VEN (corrected for body weight) and plasma concentrations of VEN (r = 0.498, P < 0.001) and ODV (r = 0.380, P = 0.001); ODV plasma concentrations were approximately 3.2 times higher than VEN plasma concentrations (VEN versus ODV = 18.60 ng/mL versus 59.10 ng/mL). VEN plasma concentrations (corrected for dose and body weight) did not differ with differing numbers of CYP2D6-mutated alleles. However, the ODV/VEN ratio decreased as the number of mutated CYP2D6 alleles increased (P = 0.001). CONCLUSIONS: This is the first study to examine the effects of CYP2D6*10 in a clinical setting. Although no effects on the plasma concentrations of VEN or ODV were observed, CYP2D6 polymorphism affects the ODV/VEN ratio. Further studies are needed to confirm the clinical relevance of these findings.

New generation antidepressants for depression in children and adolescents: a network meta-analysis.

BACKGROUND: Major depressive disorders have a significant impact on children and adolescents, including on educational and vocational outcomes, interpersonal relationships, and physical and mental health and well-being. There is an association between major depressive disorder and suicidal ideation, suicide attempts, and suicide. Antidepressant medication is used in moderate to severe depression; there is now a range of newer generations of these medications. OBJECTIVES: To investigate, via network meta-analysis (NMA), the comparative effectiveness and safety of different newer generation antidepressants in children and adolescents with a diagnosed major depressive disorder (MDD) in terms of depression, functioning, suicide-related outcomes and other adverse outcomes. The impact of age, treatment duration, baseline severity, and pharmaceutical industry funding was investigated on clinician-rated depression (CDRS-R) and suicide-related outcomes. SEARCH METHODS: We searched the Cochrane Common Mental Disorders Specialised Register, the Cochrane Library (Central Register of Controlled Trials (CENTRAL) and Cochrane Database of Systematic Reviews (CDSR)), together with Ovid Embase, MEDLINE and PsycINFO till March 2020. SELECTION CRITERIA: Randomised trials of six to 18 year olds of either sex and any ethnicity with clinically diagnosed major depressive disorder were included. Trials that compared the effectiveness of newer generation antidepressants with each other or with a placebo were included. Newer generation antidepressants included: selective serotonin reuptake inhibitors; selective norepinephrine reuptake inhibitors (SNRIs); norepinephrine reuptake inhibitors; norepinephrine dopamine reuptake inhibitors; norepinephrine dopamine disinhibitors (NDDIs); and tetracyclic antidepressants (TeCAs). DATA COLLECTION AND ANALYSIS: Two reviewers independently screened titles/abstracts and full texts, extracted data, and assessed risk of bias. We analysed dichotomous data as Odds Ratios (ORs), and continuous data as Mean Difference (MD) for the following outcomes: depression symptom severity (clinician rated), response or remission of depression symptoms, depression symptom severity (self-rated), functioning, suicide related outcomes and overall adverse outcomes. Random-effects network meta-analyses were conducted in a frequentist framework using multivariate meta-analysis. Certainty of evidence was assessed using Confidence in Network Meta-analysis (CINeMA). We used "informative statements" to standardise the interpretation and description of the results. MAIN RESULTS: Twenty-six studies were included. There were no data for the two primary outcomes (depressive disorder established via clinical diagnostic interview and suicide), therefore, the results comprise only secondary outcomes. Most antidepressants may be associated with a "small and unimportant" reduction in depression symptoms on the CDRS-R scale (range 17 to 113) compared with placebo (high certainty evidence: paroxetine: MD -1.43, 95% CI -3.90, 1.04; vilazodone: MD -0.84, 95% CI -3.03, 1.35; desvenlafaxine MD -0.07, 95% CI -3.51, 3.36; moderate certainty evidence: sertraline: MD -3.51, 95% CI -6.99, -0.04; fluoxetine: MD -2.84, 95% CI -4.12, -1.56; escitalopram: MD -2.62, 95% CI -5.29, 0.04; low certainty evidence: duloxetine: MD -2.70, 95% CI -5.03, -0.37; vortioxetine: MD 0.60, 95% CI -2.52, 3.72; very low certainty evidence for comparisons between other antidepressants and placebo). There were "small and unimportant" differences between most antidepressants in reduction of depression symptoms (high- or moderate-certainty evidence). Results were similar across other outcomes of benefit. In most studies risk of self-harm or suicide was an exclusion criterion for the study. Proportions of suicide-related outcomes were low for most included studies and 95% confidence intervals were wide for all comparisons. The evidence is very uncertain about the effects of mirtazapine (OR 0.50, 95% CI 0.03, 8.04), duloxetine (OR 1.15, 95% CI 0.72, 1.82), vilazodone (OR 1.01, 95% CI 0.68, 1.48), desvenlafaxine (OR 0.94, 95% CI 0.59, 1.52), citalopram (OR 1.72, 95% CI 0.76, 3.87) or vortioxetine (OR 1.58, 95% CI 0.29, 8.60) on suicide-related outcomes compared with placebo. There is low certainty evidence that escitalopram may "at least slightly" reduce odds of suicide-related outcomes compared with placebo (OR 0.89, 95% CI 0.43, 1.84). There is low certainty evidence that fluoxetine (OR 1.27, 95% CI 0.87, 1.86), paroxetine (OR 1.81, 95% CI 0.85, 3.86), sertraline (OR 3.03, 95% CI 0.60, 15.22), and venlafaxine (OR 13.84, 95% CI 1.79, 106.90) may "at least slightly" increase odds of suicide-related outcomes compared with placebo. There is moderate certainty evidence that venlafaxine probably results in an "at least slightly" increased odds of suicide-related outcomes compared with desvenlafaxine (OR 0.07, 95% CI 0.01, 0.56) and escitalopram (OR 0.06, 95% CI 0.01, 0.56). There was very low certainty evidence regarding other comparisons between antidepressants. AUTHORS' CONCLUSIONS: Overall, methodological shortcomings of the randomised trials make it difficult to interpret the findings with regard to the efficacy and safety of newer antidepressant medications. Findings suggest that most newer antidepressants may reduce depression symptoms in a small and unimportant way compared with placebo. Furthermore, there are likely to be small and unimportant differences in the reduction of depression symptoms between the majority of antidepressants. However, our findings reflect the average effects of the antidepressants, and given depression is a heterogeneous condition, some individuals may experience a greater response. Guideline developers and others making recommendations might therefore consider whether a recommendation for the use of newer generation antidepressants is warranted for some individuals in some circumstances. Our findings suggest sertraline, escitalopram, duloxetine, as well as fluoxetine (which is currently the only treatment recommended for first-line prescribing) could be considered as a first option. Children and adolescents considered at risk of suicide were frequently excluded from trials, so that we cannot be confident about the effects of these medications for these individuals. If an antidepressant is being considered for an individual, this should be done in consultation with the child/adolescent and their family/caregivers and it remains critical to ensure close monitoring of treatment effects and suicide-related outcomes (combined suicidal ideation and suicide attempt) in those treated with newer generation antidepressants, given findings that some of these medications may be associated with greater odds of these events. Consideration of psychotherapy, particularly cognitive behavioural therapy, as per guideline recommendations, remains important.

Enantioselective analysis of venlafaxine and its active metabolites: A review on the separation methodologies.

Venlafaxine (VFX) is a serotonin and norepinephrine reuptake inhibitor chiral drug used in therapy as an antidepressant in the form of a racemate consisting of R- and S-VFX. The two enantiomers of VFX exhibit different pharmacological activities: R-VFX inhibits both norepinephrine and serotonin synaptic reuptake, whereas S-VFX inhibits only the serotonin one. R- and S-VFX are metabolized in the liver to the respective R- and S-O-desmethylvenlafaxine (ODVFX), R- and S-N-desmethylvenlafaxine (NDVFX), and R- and S-N,O-didesmethylvenlafaxine (NODVFX). The pharmacological profile of ODVFX is close to that of VFX, whereas the other two chiral metabolites (NDVFX and NODVFX) have lower affinity for the receptor sites. The pharmacokinetics of the VFX enantiomers appear stereoselective, including the metabolism process. In the past 20 years, several studies describing the enantioselective analysis of R- and S-VFX in pharmaceutical formulations and its chiral metabolites in biological matrices were published. These methods encompass liquid chromatography coupled with UV detection, mass spectrometry, or tandem mass spectrometry, and capillary electrophoresis. This paper reviews the published methods used for the determination of the individual enantiomers of VFX and its chiral metabolites in different matrices.

Role of JNK in the Regulation of Xenobiotic Metabolizing Function of Hepatocytes.

We studied the role of JNK in the regulation of the metabolism of xenobiotic venlafaxine by liver cells under in vitro conditions. The inhibitory role of this protein kinase in the biotransformation of this psychotropic agent by hepatocytes was demonstrated. JNK inhibitor added to the liver homogenate containing antidepressant enhanced and accelerated the formation of the only pharmacologically active venlafaxine metabolite O-desmethylvenlafaxine in the cell suspension. The results show the promise of studying modifiers of activity of intracellular signaling molecules (in particular, mitogen-activated protein kinases) to develop a fundamentally new approach to control the transformation of xenobiotics and to create a new class of pharmaceutical, target regulators of drugs metabolism.

The relationship between plasma serotonin and kynurenine pathway metabolite levels and the treatment response to escitalopram and desvenlafaxine.

INTRODUCTION: The response of patients with major depressive disorders (MDD) to antidepressant treatments have been shown to be affected by multiple factors, including disease severity and inflammation. Increasing evidence indicates that the kynurenine metabolic pathway is activated by inflammation in MDD patients and plays a role in the pathophysiology of depression. Antidepressant treatments have been reported to affect kynurenine pathway metabolite levels as well. This study investigates differential associations between the antidepressant treatment outcome to escitalopram versus desvenlafaxine with the pre-treatment and post-treatment-changes in serotonin and kynurenine pathway metabolite levels. METHODS: The levels of serotonin and of kynurenine pathway metabolites were measured in plasma using liquid chromatography-mass spectrometry (LC-MS) in 161 currently depressed patients with MDD at baseline and after 8 weeks of treatment with either escitalopram or desvenlafaxine. Treatment response was defined conventionally by a reduction of at least 50% in the Hamilton Depression Rating Scale 21 item (HAMD-21) total score from baseline; remission was defined by reaching a post-treatment HAMD-21 score ≤7. RESULTS: Response to escitalopram treatment was associated with higher baseline serotonin levels (p = 0.022), lower baseline kynurenine (Kyn)/tryptophan (Trp) ratio (p = 0.008) and lower baseline quinolinic acid (QuinA)/tryptophan (Trp) ratio (p = 0.047), suggesting a lower inflammation state. Greater improvement in depression symptoms as measured by percent change of HAMD-21 score from baseline was also associated with higher baseline serotonin levels (p = 0.033) in escitalopram treatment arm. Furthermore, remitters to escitalopram treatment showed significant increases in the kynurenic acid (KynA)/3-hydroxykynurenine (3HK) ratio after treatment (p = 0.015). In contrast, response to desvenlafaxine treatment was not associated with any metabolite analyzed. We also confirmed a previous report that plasma serotonin levels are lower in MDD patients compared to healthy controls (p = 0.004) and that the kynurenine plasma level is negatively associated with depression symptom severity (p = 0.047). CONCLUSIONS: In MDD patients the antidepressant response to escitalopram was positively associated with baseline serotonin levels and inversely associated with activation of the kynurenine pathway. These results appear consistent with previous literature showing that biomarker evidence of inflammation is associated with lower response to antidepressants from the selective serotonin reuptake inhibitor class. Moreover, increases in the kynurenic acid (KynA)/3-hydroxykynurenine (3HK) ratio, which previously has been characterized as a neuroprotective index, were associated with full remission under escitalopram treatment.