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Background: This study evaluated the effect of sertraline with desvenlafaxine and sertraline with mirtazapine on HAM-D score and inflammatory markers (IL-6 and TNF-α levels) in major depressive disorder., Methods: Patients (18-60 years) with MDD diagnosed by DSM-V criteria and HAM-D score 18 or more were included ( n  = 60). Group A patients ( n  = 30) received sertraline 50 mg/day and desvenlafaxine 50 mg/day. Group B patients ( n  = 30) received sertraline 50 mg/day and mirtazapine 30 mg/day. All patients were followed up for 8 weeks for the evaluation of clinical efficacy, safety, serum IL-6, and TNF-α levels., Results: Our study showed a comparatively similar and statistically significant ( p  < 0.05) reduction in HAM-D score in both groups in the 4th and 8th week of the treatment. Both drug combinations significantly ( p  < 0.05) decreased serum IL-6 and TNF-α after 8 weeks of treatment., Conclusion: The present study suggests that the combination therapy (as treatment initiation) with sertraline and desvenlafaxine, and sertraline with mirtazapine is effective and well tolerated in MDD patients with moderate to severe depression, and their therapeutic efficacy is accompanied by decreased inflammatory markers (serum IL-6 and TNF-α).

Importance: The neurokinin 3 receptor antagonist fezolinetant 45 mg/d significantly reduced frequency/severity of moderate to severe vasomotor symptoms (VMS) of menopause compared with placebo in two phase 3 randomized controlled trials. Its efficacy relative to available therapies is unknown., Objective: We conducted a systematic review and Bayesian network meta-analysis to compare efficacy with fezolinetant 45 mg and hormone therapy (HT) and non-HT for VMS in postmenopausal women., Evidence Review: Using OvidSP, we systematically searched multiple databases for phase 3 or 4 randomized controlled trials in postmenopausal women with ≥7 moderate to severe VMS per day or ≥50 VMS per week published/presented in English through June 25, 2021. Mean change in frequency and severity of moderate to severe VMS from baseline to week 12 and proportion of women with ≥75% reduction in VMS frequency at week 12 were assessed using fixed-effect models., Findings: The network meta-analysis included data from the pooled phase 3 fezolinetant trials plus 23 comparator publications across the outcomes analyzed (frequency, 19 [34 regimens]; severity, 6 [7 regimens]; ≥75% response, 9 [15 regimens]). Changes in VMS frequency did not differ significantly between fezolinetant 45 mg and any of the 27 HT regimens studied. Fezolinetant 45 mg reduced the frequency of moderate to severe VMS events per day significantly more than all non-HTs evaluated: paroxetine 7.5 mg (mean difference [95% credible interval {CrI}], 1.66 [0.63-2.71]), desvenlafaxine 50 to 200 mg (mean differences [95% CrI], 1.12 [0.10-2.13] to 2.16 [0.90-3.40]), and gabapentin ER 1800 mg (mean difference [95% CrI], 1.63 [0.48-2.81]), and significantly more than placebo (mean difference, 2.78 [95% CrI], 1.93-3.62]). Tibolone 2.5 mg (the only HT regimen evaluable for severity) significantly reduced VMS severity compared with fezolinetant 45 mg. Fezolinetant 45 mg significantly reduced VMS severity compared with desvenlafaxine 50 mg and placebo and did not differ significantly from higher desvenlafaxine doses or gabapentin ER 1800 mg. For ≥75% responder rates, fezolinetant 45 mg was less effective than tibolone 2.5 mg (not available in the United States) and conjugated estrogens 0.625 mg/bazedoxifene 20 mg (available only as 0.45 mg/20 mg in the United States), did not differ significantly from other non-HT regimens studied and was superior to desvenlafaxine 50 mg and placebo., Conclusions: The only HT regimens that showed significantly greater efficacy than fezolinetant 45 mg on any of the outcomes analyzed are not available in the United States. Fezolinetant 45 mg once daily was statistically significantly more effective than other non-HTs in reducing the frequency of moderate to severe VMS., Relevance: These findings may inform decision making with regard to the individualized management of bothersome VMS due to menopause., Competing Interests: Financial disclosure/conflicts of interest: R.K. is a consultant to Astellas Pharma, Avion Pharma, Pharmavite, Pfizer, and TherapeuticsMD. E.G. and O.P.-L. are employees of Analysis Group, Inc., which received funding from Astellas to conduct this analysis. A.Z., S.M., and M.A. are employees of Astellas Pharma, Inc. A.M. and E.S. are employees of Astellas Pharma Europe Ltd., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The Menopause Society.)

The anatomical changes that antidepressant medications induce in the brain and through which they exert their therapeutic effects remain largely unknown. We randomized 61 patients with Persistent Depressive Disorder (PDD) to receive either desvenlafaxine or placebo in a 12-week trial and acquired anatomical MRI scans in 42 of those patients at baseline before randomization and immediately at the end of the trial. We also acquired MRIs once in 39 age- and sex-matched healthy controls. We assessed whether the serotonin-norepinephrine reuptake inhibitor, desvenlafaxine, differentially changed cortical thickness during the trial compared with placebo. Patients relative to controls at baseline had thinner cortices across the brain. Although baseline thickness was not associated with symptom severity, thicker baseline cortices predicted greater reduction in symptom severity in those treated with desvenlafaxine but not placebo. We did not detect significant treatment-by-time effects on cortical thickness. These findings suggest that baseline thickness may serve as predictive biomarkers for treatment response to desvenlafaxine. The absence of treatment-by-time effects may be attributable either to use of insufficient desvenlafaxine dosing, a lack of desvenlafaxine efficacy in treating PDD, or the short trial duration., Competing Interests: Declaration of Competing Interest This study was supported by Pfizer Pharmaceuticals via investigator-initiated funding (desvenlafaxine vs. placebo clinical trial and open-label continuation treatment) received by Drs. Hellerstein and Peterson. Pfizer Pharmaceuticals or its employees did not contribute to patient enrollment, data collection, data processing, and writing of this paper. Dr. Hellerstein has received research grants (through the Research Foundation for Mental Hygiene) from: Compass Pathways, Relmada, Marinus, Intracellular Therapies, Beckley Foundation, and from Velocity Foundation (through Columbia University); he serves on a scientific advisory board for: Reset Pharmaceuticals; and has received royalties from: Johns Hopkins University Press and Columbia University Press. All other authors report no financial relationships with commercial interests., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Therapeutic Drug Monitoring (TDM) represents one of the most promising tools in clinical practice to optimise antidepressant treatment. Nevertheless, little is still known regarding the relationship between clinical efficacy and serum concentration of venlafaxine (VEN). The aim of our study was to investigate the association between serum concentration of venlafaxine + O-desmethylvenlafaxine (SCVO) and antidepressant response (AR)., Methods: 52 depressed outpatients treated with VEN were recruited and followed in a naturalistic setting for three months. Hamilton Depression Rating Scale-21 was administered at baseline, at month 1 and at month 3 to assess AR. SCVO was measured at steady state. Linear regression analysis and nonlinear least-squares regression were used to estimate association between SCVO and AR., Results: Our results showed an association between AR and SCVO that follows a bell-shaped quadratic function with a progressive increase of AR within the therapeutic reference range of SCVO (i.e. 100-400 ng/mL) and a subsequent decrease of AR at higher serum levels., Discussion: This study strongly suggests that TDM could represent a more appropriate tool than the oral dosage to optimise the treatment with VEN. Specifically, highest efficacy might be achieved by titrating patients at SCVO levels around 400 ng/mL.

Desvenlafaxine succinate (DVS) inhibits serotonin reuptake selectively and is approved for major depressive disorders. This research investigated influence of DVS on modulating brain monoamine and oxidative stress in mice. The antiepileptic potential of DVS (10, 20, or 30 mg/kg/i.p.) in pentylenetetrazole (PTZ; 85 mg/kg) with i.p. route of administration, strychnine (STR; 75 mg/kg) with i.p. route, pilocarpine (400 mg/kg) with s.c. route and maximal electroshock MES-induced convulsion in mouse models. The activities of oxidative stress, i.e. superoxide dismutase (SOD), glutathione (GSH) and lipid peroxidation (LPO) as well as gamma-aminobutyric acid (GABA) in the brains of PTZ-induced convulsive mice. Treatment with DVS increased the latency to develop siezures and declined mortalities in rodents against PTZ, STR and pilocarpine-induced convulsions. Results of MES-leaded siezures revealed that DVS reduced tonic hind limb extension duration and mortalities significantly. Brain, SOD, GSH and GABA level were significantly (P<0.01) increased and LPO reduced significantly (P<0.01) after DVS treatment. Furthermore, the DVS did not show any motor coordination signs in the rotarod test. We demonstrated that the role of DVS in convulsion genesis in mice under control condition and attenuate the PTZ-induced oxidative damage.

The US Food and Drug Administration (FDA) lists 22 medications as clinical inhibitors of cytochrome P450 2D6 isoenzyme, with classifications of strong, moderate, and weak. It is accepted that strong inhibitors result in nearly null enzymatic activity, but reduction caused by moderate and weak inhibitors is less well characterized. The objective was to identify if the classification of currently listed FDA moderate and weak inhibitors is supported by publicly available primary literature. We conducted a literature search and reviewed product labels for area under the plasma concentration-time curve (AUC) fold-changes caused by inhibitors in humans and identified 89 inhibitor-substrate pairs. Observed AUC fold-change of the substrate was used to create an observed inhibitor classification per FDA-defined AUC fold-change thresholds. We then compared the observed inhibitor classification with the classification listed in the FDA Table of Inhibitors. We found 62% of the inhibitors within the pairs matched the listed FDA classification. We explored reasons for discordance and suggest modifications to the FDA table of clinical inhibitors for cimetidine, desvenlafaxine, and fluvoxamine., (© 2020 The Authors Clinical Pharmacology & Therapeutics © 2020 American Society for Clinical Pharmacology and Therapeutics.)

Background: Antidepressant medications offer an effective treatment for depression, yet nearly 50% of patients either do not respond or have side-effects rendering them unable to continue the course of treatment. Mechanistic studies might help advance the pharmacology of depression by identifying pathways through which treatments exert their effects. Toward this goal, we aimed to identify the effects of antidepressant treatment on neural connectivity, the relationship with symptom improvement, and to test whether these effects were reproducible across two studies., Methods: We completed two double-blind, placebo-controlled trials of SNRI antidepressant medications with MRI scans obtained before and after treatment. One was a 10-week trial of duloxetine (30-120 mg daily; mean 92·1 mg/day [SD 30·00]) and the other was a 12-week trial of desvenlafaxine (50-100 mg daily; 93·6 mg/day [16·47]). Participants consisted of adults with persistent depressive disorder. Adjusting for sex and age, we examined the effect of treatment on whole-brain functional connectivity. We also examined correlations between change in functional connectivity and improvement in symptoms of depression (24-item Hamilton Depression Rating Scale) and pain symptom severity (Symptom Checklist-90-Revised)., Findings: Participants were enrolled between Jan 26, 2006, and Nov 22, 2011, for the duloxetine RCT and Aug 5, 2012, and Jan 28, 2016, for the desvenlafaxine RCT. Before and after treatment MRI scans were collected in 32 participants for the duloxetine RCT and 34 participants for the desvenlafaxine RCT. In both studies, antidepressants decreased functional connectivity compared with placebo (duloxetine study: β=-0·06; 95% CI -0·08 to -0·03; p<0·0001, η p 2 =0·44; desvenlafaxine study: -0·06, -0·09 to -0·03; p<0·0001, η p 2 =0·35) within a thalamo-cortico-periaqueductal network that has previously been associated with the experience of pain. Within the active drug groups, reductions in functional connectivity within this network correlated with improvements in depressive symptom severity in both studies (duloxetine study: r=0·38, 95% CI 0·01-0·65; p=0·0426; desvenlafaxine study: 0·44, 0·10-0·69; p=0·0138) and pain symptoms in the desvenlafaxine study (0·39, 0·04 to 0·65; p=0·0299)., Interpretation: The findings suggest the thalamo-cortico-periaqueductal network associated with the experience of pain is a new and potentially important target for novel antidepressant therapeutics., Funding: National Mental Health Institute, Eli Lilly and Company, Pfizer Pharmaceuticals, and the Edwin S Webster Foundation., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Myocardial infarction (MI) in animal models induces cognitive deficits as well as the activation of caspase in the limbic system; both can be blocked by 2 weeks of treatment following MI using tricyclic antidepressants or selective serotonin uptake blockers. Here we used three different treatment schedules to test the short- and long-term effects of the combined serotonin-norepinephrine reuptake inhibitor desvenlafaxine on post-MI-associated cognitive deficits and caspase activation. MI was induced in 39 young adult rats, and 39 rats served as sham-operated controls. Desvenlafaxine (3 mg/kg/day, i.p.) or saline was administered according to one of three schedules: (1) for 2 weeks, starting right after surgery; (2) for 16 weeks, starting 2 weeks after surgery; (3) for 16 weeks, starting right after surgery. Behavior was tested 2 weeks (social interaction, passive avoidance) and 16 weeks (forced swimming, Morris water maze) after surgery. Caspase-3 and caspase-6 activities were measured 16 weeks after surgery. At 2 and 16 weeks post-surgery, saline-treated MI rats displayed performance deficits compared to desvenlafaxine-treated rats, regardless of the treatment schedule. Caspase-3 activity was higher in the amygdala (medial and lateral) and hippocampal CA3 region in untreated MI rats, whereas caspase-6 activity was higher in the CA1 region. Caspase-6 activity correlated positively with deficits in the Morris water maze. These results indicate that, independently of treatment schedules, various treatment schedules with desvenlafaxine can prevent MI-associated cognitive deficits and decrease caspase activities in the limbic system.

SEP-227162 [R(-)-O-desmethylvenlafaxine] is an enantiomer of the venlafaxine metabolite O-desmethylvenlafaxine (ODV, Pristiq™, Wyeth). This study compared the serotonin transporter (SERT) occupancy achieved by SEP-227162 and ODV, at daily doses of 25, 50, 100, and 150 mg using [ 11 C]DASB positron emission tomography (PET). Sixteen healthy male subjects participated in one of four dose groups (N = 4 per group) during which they were administered two doses of the study drug (SEP-227162 or ODV). For each study drug, total daily doses of 25, 50, 100, and150 mg were studied. Subjects underwent three PET scans with [ 11 C]DASB. A baseline, off-medication, scan was performed prior to dosing and a [ 11 C]DASB PET scan was performed after 72 hr at each dose level. [ 11 C]DASB binding potential (BP ND ) was calculated using the simplified reference tissue method. SERT occupancy was calculated as the change in BP ND (ΔBP ND ) from baseline scan to the on-medication scan relative to the baseline BP ND value. SEP-227162 and ODV significantly reduced regional distribution volumes and region BP ND values in a dose-dependent manner. Across all doses ODV produced significantly greater SERT occupancy than SEP-227162 (ANOVA F = 21.8, df = 1,23, p < .001). The total daily dose required to provide 50% SERT occupancy was 24.8 mg for SEP-227162 and 14.4 mg for ODV. In vitro data suggests a ratio of 3.3:1 for binding at human SERT for SEP-227162 relative to ODV. Our study suggests a ratio of 1.7:1, highlighting the value of in vivo imaging in the drug development process., (© 2017 Wiley Periodicals, Inc.)

Purpose: This post hoc meta-analysis evaluated the efficacy and safety of desvenlafaxine 50 and 100 mg versus placebo across age groups and severity of depression at baseline in patients with major depressive disorder., Methods: Data from placebo and desvenlafaxine 50-mg and 100-mg dose arms were pooled from 9 short-term, placebo-controlled, major depressive disorder studies (N = 4279). Effects of age (18-40 years, >40 to <55 years, 55-<65 years, and ≥65 years) and baseline depression severity (mild, 17-item Hamilton Rating Scale for Depression total score [HAM-D17] ≤18; moderate, HAM-D17 >18 to <25; severe, HAM-D17 ≥25) on desvenlafaxine efficacy were assessed using analysis of covariance for continuous end points and logistic regression for categorical end points., Findings: Desvenlafaxine-treated (50 or 100 mg/d) patients had significantly (P < 0.05, 2-sided) greater improvement in most measures of depression and function compared with placebo for patients 18 to 40 years, older than 40 to younger than 55 years, and 55 to younger than 65 years, with no significant evidence of an effect of age. Desvenlafaxine significantly improved most measures of depression and function in moderately and severely depressed patients. There was a significant baseline severity by treatment interaction for HAM-D17 total score only (P = 0.027), with a larger treatment effect for the severely depressed group., Implications: Desvenlafaxine significantly improved depressive symptoms in patients younger than 65 years and in patients with moderate or severe baseline depression. Sample sizes were not adequate to assess desvenlafaxine efficacy in patients 65 years or older or with mild baseline depression.

Background: Major depressive disorder (MDD) is associated with staggering personal and economic costs, a major proportion of which stem from impaired psychosocial and occupational functioning. Few studies have examined the impact of depression-related cognitive dysfunction on work functioning. We examined the association between neurocognitive and work functioning in employed patients with MDD., Methods: Employed adult outpatients (n=36) with MDD of at least moderate severity (≥23 on the Montgomery Asberg Depression Rating Scale, MADRS) and subjective cognitive complaints completed neurocognitive tests (CNS Vital Signs computerized battery) and validated self-reports of their work functioning (LEAPS, HPQ) before and after 8 weeks of open-label treatment with flexibly-dosed desvenlafaxine 50-100mg/day. Relationships between neurocognitive tests and functional measures were examined using bivariate correlational and multiple regression analyses, as appropriate. An ANCOVA model examined whether significant change in neurocognitive performance, defined as improvement of ≥1SD in the Neurocognition Index (NCI) from baseline to post-treatment, was associated with improved outcomes., Results: Patients showed significant improvements in depressive symptom, neurocognitive, and work functioning measures following treatment with desvenlafaxine (e.g., MADRS response=77% and MADRS remission=49%). There were no significant correlations between changes in NCI or cognitive domain subscales and changes in MADRS, LEAPS, or HPQ scores. However, patients demonstrating significant improvement in NCI scores (n=11, 29%) had significantly greater improvement in clinical and work functioning outcomes compared to those without NCI improvement., Limitations: The limitations of this study include small sample size, lack of a placebo control group, and lack of a healthy comparison group. Our sample also had more years of education and higher premorbid intelligence than the general population., Conclusions: There were no significant correlations between changes in neurocognitive and work functioning measures in this study. However, meaningful improvement in neurocognitive functioning with desvenlafaxine was associated with greater improvement in both mood and occupational outcomes. This suggests that addressing cognitive dysfunction may improve clinical and occupational outcomes in employed patients with MDD. However, the relationship between neurocognitive and work functioning in MDD is complex and requires further study., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Oxidative stress is implicated in the neurobiology of depression. Here we investigated oxidative alterations in brain areas of animals submitted to the model of depression induced by corticosterone (CORT) and the effects of the antioxidant compound alpha-lipoic acid (ALA) alone or associated with the antidepressant desvenlafaxine (DVS) in these alterations. Female mice received vehicle or CORT (20 mg/kg) during 14 days. From the 15th to 21st days different animals received further administrations of: vehicle, DVS (10 or 20 mg/kg), ALA (100 or 200 mg/kg), or the combinations of DVS10+ALA100, DVS20+ALA100, DVS10+ALA200, or DVS20+ALA200. Twenty-four hours after the last drug administration prefrontal cortex (PFC), hippocampus (HC) and striatum (ST) were dissected for the determination of the activity of superoxide dismutase (SOD), reduced glutathione (GSH) and lipid peroxidation (LP) levels. CORT significantly increased SOD activity in the PFC and HC, decreased GSH levels in the HC and increased LP in all brain areas studied when compared to saline-treated animals. Decrements of SOD activity were observed in all groups and brain areas studied when compared to controls and CORT. The hippocampal decrease in GSH was reversed by ALA100, DVS10+ALA100, DVS20+ALA100 and DVS20+ALA200. The same DVS+ALA combination groups presented increased levels of GSH in the PFC and ST. The greater GSH levels were observed in the PFC, HC and ST of DVS20+ALA200 mice. LP was reversed in the groups ALA200 (PFC), DVS10+ALA100, DVS20+ALA100 (PFC, HC and ST), and DVS20+ALA200 (PFC, HC). Our findings contribute to the previous preclinical evidences implicating ALA as a promising agent for augmentation therapy in depression., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Potential drugdrug interactions are a concern for patients taking tamoxifen., Objective: This study was designed to determine the effect of coadministering desvenlafaxine on tamoxifen pharmacokinetics., Materials and Methods: This open-label, 2-period inpatient and outpatient study enrolled healthy, postmenopausal women. Period 1, day 1, subjects were administered tamoxifen 40 mg followed by 23 days of blood sampling for pharmacokinetic analyses. During period 2, subjects received desvenlafaxine 100 mg/d for 28 days; a single dose of tamoxifen 40 mg was administered with desvenlafaxine 100 mg on day 7, followed by 23 days of blood sampling. Pharmacokinetics of tamoxifen and its metabolites (AUC over infinite time (AUC(inf)), AUC to the last measurable concentration (AUC(last)), peak plasma concentration (C(max)) were compared for monotherapy vs. combination therapy using the ratio of adjusted mean differences. A superposition method was used in the statistical analysis of N-desmethyl-tamoxifen and endoxifen to address the carry-over observed for those metabolites. The test for interaction was considered negative if the 90% confidence intervals (CIs) for the ratios were within 80 - 125%., Results: Coadministration of tamoxifen with steady-state desvenlafaxine did not alter tamoxifen AUC(inf), AUC(last), and C(max), as reflected by the ratio of adjusted geometric means (90% CIs) of 100.7% (96.7%, 104.9%), 103.5% (100.2%, 106.9%), and 99.4% (94.0%, 105.2%), respectively. Similarly, coadministration did not alter 4-hydroxy- tamoxifen and N-desmethyl-amoxifen pharmacokinetics. The 11.8% (88.2% (82.6%, 94.2%)) and 8.0% (92.0% (84.7%, 100.0%)) decreases in endoxifen AUC(last) and C(max), respectively, were not significant (90% CIs fell wholly within the prespecified acceptance range)., Conclusions: Steady-state desvenlafaxine 100 mg did not affect tamoxifen pharmacokinetics. For women treated with tamoxifen, desvenlafaxine may represent a safe and effective treatment unlikely to alter tamoxifen efficacy.

Introduction: Early assessment of a therapeutic response is a central goal in antidepressant treatment. The present study examined the potential for therapeutic drug monitoring and symptom rating to predict venlafaxine treatment efficacy (measured by overall patient response and remission)., Methods: 88 patients were uptitrated homogenously to 225 mg/day venlafaxine. Serum concentrations of venlafaxine (VEN) and its active metabolite O-desmethylvenlafaxine (ODV) were measured at week 2. Continuous psychopathometric ratings were measured for up to 6 weeks by independent study raters., Results: An early improvement was significantly more common in venlafaxine responders than non-responders (χ(2); p=0.007). While ODV serum levels were significantly higher in responders (t test; p=0.006), VEN serum levels, sum level of VEN+ODV and the ratio of ODV/VEN levels were not. Moreover, patients who showed an early response combined with an ODV serum level above the median of 222 ng/mL were significantly more likely to achieve full response (binary logistic model; p<0.01). Sensitivity (84% for early response) and specificity (81% for combination of early response and therapeutic drug monitoring) were sufficient to qualify as a reasonable screening instrument., Conclusion: Our results indicate that early improvement and ODV serum concentration are predictive of therapeutic outcome and can thus be used to guide use of the antidepressant venlafaxine., (© Georg Thieme Verlag KG Stuttgart · New York.)

Triple reuptake inhibitors (TRIs) are currently being developed as a new class of promising antidepressants that block serotonin (5-HT), dopamine (DA) and norepinephrine (NE) transporters, thereby increasing extracellular monoamine concentrations. The purpose of this study was to investigate the effects of LPM570065, a novel TRI and a desvenlafaxine prodrug, on extracellular 5-HT, DA and NE levels in the rat striatum after acute and chronic administration relative to desvenlafaxine, using High Performance Liquid Chromatography (HPLC) and microdialysis. Acute administration was performed by providing rodents with oral solutions (0.06 mmol·kg(-1) p.o.), oral suspensions (0.06 mmol·kg(-1) p.o.) and intravenous solutions (0.04 mmol·kg(-1) i.v.) of LPM570065 and desvenlafaxine. Oral suspensions (0.06 mmol·kg(-1)·day(-1)) of the two drugs were also administered for a 14-day chronic period. HPLC analysis revealed that LPM570065 rapidly penetrated the rat striatum, converted into desvenlafaxine and exhibited larger total exposure compared with the administration of desvenlafaxine. Microdialysis revealed that acute and chronic administration of oral suspension of LPM570065 increased the 5-HT, DA and NE levels more than the relative administration of desvenlafaxine. Unlike desvenlafaxine, acute administration of an intravenous LPM570065 solution did not induce the undesirable 90% decrease in extracellular 5-HT levels. In contrast to the fully dose-dependent elevation of 5-HT induced by desvenlafaxine, the acute administration of LPM570065 showed a capped increase in extracellular 5-HT levels when combined with WAY-100635. Additionally, forced swim test demonstrated that acute and chronic administration of LPM570065 reduced the immobility time more than the relative administration of desvenlafaxine. These data suggest that LPM570065 may have greater efficacy and/or a more rapid onset of antidepressant action than desvenlafaxine and also counterbalance the harmful effects of desvenlafaxine on 5-HT neurotransmission related to 5-HT1A autoreceptors. Thus, this new class of drugs, TRIs has the potential to provide a new therapeutic mechanism for treating depression.