Neurochemical evaluation of the novel 5-HT1A receptor partial agonist/serotonin reuptake inhibitor, vilazodone

Vilazodone, a Novel SSRI Antidepressant with 5-HT1A Partial Agonist Properties: Diminished Potentiation of Chronic Oral Methylphenidate-Induced Dynorphin Expression in the Striatum in Adolescent Male Rats

Selective serotonin reuptake inhibitor (SSRI) antidepressants such as fluoxetine are used in combination with the medical psychostimulant methylphenidate (Ritalin) in a variety of treatments in children and adults. Unintended co-exposure to these psychotropic medications also occurs in patients on SSRIs who abuse methylphenidate as a "cognitive enhancer" or recreational drug. Preclinical research shows that SSRIs such as fluoxetine when given in conjunction with methylphenidate potentiate addiction-related gene regulation by methylphenidate in the striatum, consistent with the known facilitatory role for serotonin in psychostimulant-induced neuronal and behavioral changes. Moreover, fluoxetine combined with methylphenidate also facilitated subsequent acquisition of cocaine self-administration in adolescent rats, suggesting an increased addiction liability for methylphenidate. In the present study, we investigated the impact of a novel SSRI, vilazodone, on methylphenidate-induced gene regulation in adolescent male rats. In contrast to prototypical SSRIs such as fluoxetine, vilazodone also acts as a partial 5-HT1A serotonin receptor agonist and is thus proposed to temper serotonin input to the striatum. We compared the effects of chronic treatment (4 weeks) with vilazodone (10 mg/kg, twice daily) with those of fluoxetine (5 mg/kg, twice daily) on striatal dynorphin expression induced by oral methylphenidate treatment (30/60 mg/kg/day in drinking water, 8 h access daily). Our results demonstrate that, in contrast to fluoxetine, vilazodone had minimal or no potentiating effects on methylphenidate-induced dynorphin expression. This diminished impact on gene regulation was seen throughout the striatum, including the nucleus accumbens, where increased dynorphin expression has previously been associated with various aspects of addiction. Our findings suggest that vilazodone may serve as a better adjunct SSRI with reduced addiction-facilitating properties.

Discovery of a Novel Multitarget Analgesic Through an In Vivo-Guided Approach

Background: Pain is a complex condition influenced by peripheral, central, immune, and psychological factors. Multitarget approaches offer a more effective and safer alternative to single-target analgesics by enhancing efficacy, reducing side effects, and minimizing tolerance. This study aimed to identify a novel multitarget analgesic with improved pharmacological properties. Methods: An in vivo-guided screening approach was used to discover a new analgesic compound. Compound 29, derived from a novel scaffold inspired by opiranserin and vilazodone pharmacophores, was identified through analog screening in the formalin test. Its efficacy was further evaluated in the spinal nerve ligation (SNL) model of neuropathic pain. Mechanistic studies explored its interaction with neurotransmitter transporters and receptors, while pharmacokinetic and safety assessments were conducted to determine its stability, brain penetration, and potential toxicity. Results: Compound 29 demonstrated high potency in the formalin test, with an ED50 of 0.78 mg/kg in the second phase and a concentration-dependent effect in the first phase. In the SNL model, it produced dose-dependent analgesic effects, increasing withdrawal thresholds by 24% and 45% maximum possible effect (MPE) at 50 and 100 mg/kg, respectively. Mechanistic studies revealed strong triple uptake inhibition, particularly at dopamine (DAT) and serotonin (SERT) transporters, alongside high-affinity 5-HT2A receptor antagonism. Pharmacokinetic analysis indicated enhanced stability and blood-brain barrier permeability. In vitro studies confirmed its nontoxicity to HT-22 cells but revealed potential hERG inhibition and strong CYP3A4 inhibition. Conclusions: Compound 29 is a promising multitarget analgesic with potent efficacy and favorable pharmacokinetics. Ongoing optimization efforts aim to mitigate side effects and enhance its therapeutic profile for clinical application.

(-)-Syringaresinol Exerts an Antidepressant-like Activity in Mice by Noncompetitive Inhibition of the Serotonin Transporter

BACKGROUND

Albizia julibrissin Durazz. is one of the most popular herbs used for depression treatment, but the molecular basis for its mechanism of action has not been fully addressed. Previously, we isolated and identified two lignan glycoside derivatives that were shown to noncompetitively inhibit serotonin transporter (SERT) activity but with a relatively low inhibitory potency compared with those of conventional antidepressants.

METHODS

We characterized the pharmacological profile of the parental compound of these previously isolated lignan glycosides, (-)-syringaresinol (SYR), in inhibiting SERT by using biochemical, pharmacological, and behavioral approaches.

RESULTS

SYR, as a potent inhibitor, decreases SERT Vmax but with little change in Km for its fluorescent substrate. SYR was shown to block the conformational conversion essential for substrate transport by stabilizing SERT in an outward-open and inward-closed conformation. In addition, our molecular docking and biochemical validation demonstrated that SYR binds to an allosteric site in SERT and noncompetitively inhibits SERT transport and binding activity. Furthermore, administration of SYR was indicated to exert an antidepressant-like activity and to effectively attenuate chronic unpredictable mild stress (CUMS)-induced abnormalities in behaviors and synaptic protein expression in depressive animal models.

CONCLUSIONS

This study not only provides molecular insights into the mechanism of action of A. julibrissin in the treatment of depression, but also opens up the possibility of development of a novel class of allosteric site-targeted therapeutic agents with an underlying mechanism of action different from that of conventional antidepressants.

Synthesis and biological evaluation of multimodal monoaminergic arylpiperazine derivatives with potential antidepressant profile

Depression is a common psychiatric disorder with an estimated global prevalence of 4.4 %. Here, we designed a series of new multimodal monoaminergic arylpiperazine derivatives using a pharmacophore hybrid approach and synthesized them for the treatment of depression. Molecular docking was employed to elucidate the differences in activity and selectivity of the corresponding compounds on SERT, NET, and DAT. In vitro experiments demonstrated that compound A3 has a relatively balanced multi-target activity profile with SERT reuptake inhibition (IC50 = 12 nM), NET reuptake inhibition (IC50 = 78 nM), DAT reuptake inhibition (IC50 = 135 nM), and 5-HT1AR agonism (EC50 = 34 nM). Pharmacokinetic experiments revealed that A3 exhibited excellent bioavailability and low clearance in mice. Subsequent behavioral experiments further confirmed its significant antidepressant effects. These results further highlight the rationality of our design strategy.

Structural pharmacology and therapeutic potential of 5-methoxytryptamines

Psychedelic substances such as lysergic acid diethylamide (LSD) and psilocybin show potential for the treatment of various neuropsychiatric disorders1-3. These compounds are thought to mediate their hallucinogenic and therapeutic effects through the serotonin (5-hydroxytryptamine (5-HT)) receptor 5-HT2A (ref. 4). However, 5-HT1A also plays a part in the behavioural effects of tryptamine hallucinogens5, particularly 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), a psychedelic found in the toxin of Colorado River toads6. Although 5-HT1A is a validated therapeutic target7,8, little is known about how psychedelics engage 5-HT1A and which effects are mediated by this receptor. Here we map the molecular underpinnings of 5-MeO-DMT pharmacology through five cryogenic electron microscopy (cryo-EM) structures of 5-HT1A, systematic medicinal chemistry, receptor mutagenesis and mouse behaviour. Structure-activity relationship analyses of 5-methoxytryptamines at both 5-HT1A and 5-HT2A enable the characterization of molecular determinants of 5-HT1A signalling potency, efficacy and selectivity. Moreover, we contrast the structural interactions and in vitro pharmacology of 5-MeO-DMT and analogues to the pan-serotonergic agonist LSD and clinically used 5-HT1A agonists. We show that a 5-HT1A-selective 5-MeO-DMT analogue is devoid of hallucinogenic-like effects while retaining anxiolytic-like and antidepressant-like activity in socially defeated animals. Our studies uncover molecular aspects of 5-HT1A-targeted psychedelics and therapeutics, which may facilitate the future development of new medications for neuropsychiatric disorders.

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

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

The clinical utility of newer antidepressant agents: Understanding the role in management of MDD

Whereas MDD is characterized in part by changes in mood, other symptoms can also cause significant impairment, including sexual dysfunction, cognitive impairment, and fatigue. Newer antidepressants are explored with the goal of more optimally treating these non–mood-related symptoms of MDD. The 3 oral antidepressants that have been FDA-approved most recently include vortioxetine, vilazodone, and levomilnacipran. Unique features of these antidepressants are explored through 3 patient cases.

The effects of Vilazodone, YL-0919 and Vortioxetine in hemiparkinsonian rats

Parkinson's disease is a neurodegenerative disease often characterized by motor deficits and most commonly treated with dopamine replacement therapy. Despite its benefits, chronic use of L-DOPA results in abnormal involuntary movements known as L-DOPA-induced dyskinesia. Growing evidence shows that with burgeoning dopamine cell loss, neuroplasticity in the serotonin system leads to the development of L-DOPA-induced dyskinesia through the unregulated uptake, conversion, and release of L-DOPA-derived dopamine into the striatum. Previous studies have shown that coincident 5-HT_1A agonism and serotonin transporter inhibition may have anti-dyskinetic potential. Despite this, few studies have explicitly focused on targeting both 5-HT_1A and the serotonin transporter. The present study compares the 5-HT compounds Vilazodone, YL-0919, and Vortioxetine which purportedly work as simultaneous 5-HT_1A receptor agonists and SERT blockers. To do so, adult female Sprague Dawley rats were rendered hemiparkinsonian and treated daily for two weeks with L-DOPA to produce stable dyskinesia. The abnormal involuntary movements and forehand adjusting step tests were utilized as measurements for L-DOPA-induced dyskinesia and motor performance in a within-subjects design. Lesion efficacy was determined by analysis of striatal monoamines via high-performance liquid chromatography. Compounds selective for 5-HT_1A/SERT target sites including Vilazodone and Vortioxetine significantly reduced L-DOPA-induced dyskinesia without compromising L-DOPA pro-motor efficacy. In contrast, YL-0919 failed to reduce L-DOPA-induced dyskinesia, with no effects on L-DOPA-related improvements. Collectively, this work supports pharmacological targeting of 5-HT_1A/SERT to reduce L-DOPA-induced dyskinesia. Additionally, this further provides evidence for Vilazodone and Vortioxetine, FDA-approved compounds, as potential adjunct therapeutics for L-DOPA-induced dyskinesia management in Parkinson's patients.

Sexual dysfunction with major depressive disorder and antidepressant treatments: impact, assessment, and management

INTRODUCTION

Sexual dysfunction (SD) is a symptom of depression in ≈70% of patients presenting with major depressive disorder (MDD). Antidepressant medications (AD) and adjunctive treatments may further contribute to SD and complicate evaluation and management.

AREAS COVERED

A systematic literature search of PubMed, Ovid MEDLINE and Cochrane databases for MDD, SD, classes of antidepressants, etc. was performed with a focus on 2014 to June 2021. SSRIs are associated with 70% treatment-emergent sexual dysfunction (TESD), SNRIs and tricyclics have rates of TESD of 40 - 45%, and antidepressant medications without SRI effects or with additional unique mechanisms of action have rates similar to placebo (<10%). Appropriate assessment at baseline and throughout treatment, consideration of patient preferences in prescribing, addressing modifiable factors (comorbid medical/psychiatric conditions, substances, relationship difficulties), and utilizing management strategies of switching to an AD with less SD, adding an antidote/adjunctive therapy or lowering the dose are discussed.

EXPERT OPINION

MDD and antidepressant treatment contribute to SD in a high percentage of patients. Treating to remission reduces SD as a symptom of depression. Frequent assessment and targeted management strategies may be effective in preventing or addressing SD. Secondary outcomes like impact on adherence, relationships and self-image should also be considered.

Vilazodone for Major Depression in Adults: Pharmacological Profile and an Updated Review for Clinical Practice

This article provides an updated review of the pharmacological profile and available efficacy and tolerability/safety data for vilazodone, one of the most recent antidepressant drugs to be approved in the USA for the treatment of major depressive disorder (MDD) in adults. The efficacy of vilazodone for MDD in adults is supported by four positive short-term (8-10 weeks), randomized, placebo-controlled trials. Beyond these pivotal trials, we review updated research findings pertaining to the clinical effects of vilazodone for MDD including the results of switch studies, small comparative efficacy trials, key pooled and secondary data analyses focused on important depressive subtypes (anxious depression) and predictors of treatment outcome, and safety studies including direct studies of sexual side-effects. Despite these additional research efforts and use for over a decade, important gaps in the clinical evidence base remain with vilazodone. Hypothesized differences in efficacy and adverse effects between other antidepressants and vilazodone based on its multimodal mechanism of action (combining serotonin reuptake inhibition with serotonin 5-HT1A partial agonist effects) have not been comprehensively demonstrated in clinical studies and its effectiveness as a continuation- or maintenance-phase therapeutic is not yet established. Questions remain regarding its reproductive and lactational safety profiles and its efficacy as a potential next-step therapeutic for patients with MDD who do not respond to first-line antidepressants such as selective serotonin reuptake inhibitors. Suggestions for clinical use of vilazodone and discussion of its place among the broad range of pharmacotherapies for adults with MDD are provided.

Role of 5-HT1A Receptor in Vilazodone-Mediated Suppression of L-DOPA-Induced Dyskinesia and Increased Responsiveness to Cortical Input in Striatal Medium Spiny Neurons in an Animal Model of Parkinson's Disease

L-DOPA therapy in Parkinson’s disease (PD) is limited due to emerging L-DOPA-induced dyskinesia. Research has identified abnormal dopamine release from serotonergic (5-HT) terminals contributing to this dyskinesia. Selective serotonin reuptake inhibitors (SSRIs) or 5-HT receptor (5-HTr) agonists can regulate 5-HT activity and attenuate dyskinesia, but they often also produce a loss of the antiparkinsonian efficacy of L-DOPA. We investigated vilazodone, a novel multimodal 5-HT agent with SSRI and 5-HTr_1A partial agonist properties, for its potential to reduce dyskinesia without interfering with the prokinetic effects of L-DOPA, and underlying mechanisms. We assessed vilazodone effects on L-DOPA-induced dyskinesia (abnormal involuntary movements, AIMs) and aberrant responsiveness to corticostriatal drive in striatal medium spiny neurons (MSNs) measured with in vivo single-unit extracellular recordings, in the 6-OHDA rat model of PD. Vilazodone (10 mg/kg) suppressed all subtypes (axial, limb, orolingual) of AIMs induced by L-DOPA (5 mg/kg) and the increase in MSN responsiveness to cortical stimulation (shorter spike onset latency). Both the antidyskinetic effects and reversal in MSN excitability by vilazodone were inhibited by the 5-HTr_1A antagonist WAY-100635, demonstrating a critical role for 5-HTr_1A in these vilazodone actions. Our results indicate that vilazodone may serve as an adjunct therapeutic for reducing dyskinesia in patients with PD.

Use of Sertraline in Hemodialysis Patients

Depression and anxiety are the most common psychiatric disorders in end-stage renal disease (ESRD) patients treated with hemodialysis (HD) and may correlate with lower quality of life and increased mortality. Depression treatment in HD patients is still a challenge both for nephrologists and psychiatrists. The possible treatment of depressive disorders can be pharmacological and non-pharmacological. In our article, we focus on the use of sertraline, the medication which seems to be relatively safe and efficient in the abovementioned population, taking under consideration several limitations regarding the use of other selective serotonin reuptake inhibitors (SSRIs). In our paper, we discuss different aspects of sertraline use, taking into consideration possible benefits and side effects of drug administration like impact on QTc (corrected QT interval) prolongation, intradialytic hypotension (IDH), chronic kidney disease-associated pruritus (CKD-aP), bleeding, sexual functions, inflammation, or fracture risk. Before administering the medication, one should consider benefits and possible side effects, which are particularly significant in the treatment of ESRD patients; this could help to optimize clinical outcomes. Sertraline seems to be safe in the HD population when provided in proper doses. However, we still need more studies in this field since the ones performed so far were usually based on small samples and lacked placebo control.

The antidepressant drug vilazodone is an allosteric inhibitor of the serotonin transporter

Depression is a common mental disorder. The standard medical treatment is the selective serotonin reuptake inhibitors (SSRIs). All characterized SSRIs are competitive inhibitors of the serotonin transporter (SERT). A non-competitive inhibitor may produce a more favorable therapeutic profile. Vilazodone is an antidepressant with limited information on its molecular interactions with SERT. Here we use molecular pharmacology and cryo-EM structural elucidation to characterize vilazodone binding to SERT. We find that it exhibits non-competitive inhibition of serotonin uptake and impedes dissociation of [³H]imipramine at low nanomolar concentrations. Our SERT structure with bound imipramine and vilazodone reveals a unique binding pocket for vilazodone, expanding the boundaries of the extracellular vestibule. Characterization of the binding site is substantiated with molecular dynamics simulations and systematic mutagenesis of interacting residues resulting in decreased vilazodone binding to the allosteric site. Our findings underline the versatility of SERT allosteric ligands and describe the unique binding characteristics of vilazodone.

Vilazodone (VLZ) is a drug for the treatment of major depressive disorders that targets the serotonin transporter (SERT). Here, the authors combine pharmacology measurements and cryo-EM structural analysis to characterize VLZ binding to SERT and observe that VLZ exhibits non-competitive inhibition of serotonin transport and binds with nanomolar affinity to an allosteric site in SERT.

Early response to trazodone once-a-day in major depressive disorder: review of the clinical data and putative mechanism for faster onset of action

BACKGROUND

Most antidepressants have a delayed onset of action and must be administered for several weeks to generate therapeutic effects. Trazodone is a serotonin antagonist and reuptake inhibitor approved for the treatment of major depressive disorder. The once-a-day (OAD) formulation of trazodone has an improved tolerability profile compared to its conventional formulations. In this study, we systematically reviewed the evidence available for the antidepressant efficacy and early improvement in depressive symptoms with trazodone OAD treatment.

METHOD

We conducted a PubMed database search for randomized controlled trials published from 2005 to 2020.

RESULTS

Two studies, a placebo-controlled and an active-comparator (venlafaxine extended-release or XR) study were found. Both the studies demonstrated that trazodone exhibits antidepressant activity at a starting dose of 150 mg/day and results in statistically significant greater reduction in Hamilton Depression Rating Scale (HAM-D17) scores within 1 week of starting treatment compared to placebo or venlafaxine XR (P < .05). Trazodone also resulted in significant early improvement in the HAM-D17 sleep disturbance factor compared to placebo or venlafaxine XR at day 7 (P < .05). This clinical effect is supported by in vitro proprietary data for the affinity of trazodone for different target receptors. Activity at these receptors may underlie trazodone's fast antidepressant action.

CONCLUSIONS

Trazodone, if properly dosed, can be an effective antidepressant with early onset of action and good tolerability. Future studies designed to specifically evaluate onset and timing of improvement of depressive symptoms remain necessary to confirm and extend these results.

Serotonin/dopamine interaction: Electrophysiological and neurochemical evidence

The interaction between serotonin (5-HT) and dopamine (DA) in the central nervous system (CNS) plays an important role in the adaptive properties of living animals to their environment. These are two modulatory, divergent systems shaping and regulating in a widespread manner the activity of neurobiological networks and their interaction. The concept of one interaction linking these two systems is rather elusive when looking at the mechanisms triggered by these two systems across the CNS. The great variety of their interacting mechanisms is in part due to the diversity of their neuronal origin, the density of their fibers in a given CNS region, the distinct expression of their numerous receptors in the CNS, the heterogeneity of their intracellular signaling pathway that depend on the cellular type expressing their receptors, and the state of activity of neurobiological networks, conditioning the outcome of their mutual influences. Thus, originally conceptualized as inhibition of 5-HT on DA neuron activity and DA neurotransmission, this interaction is nowadays considered as a multifaceted, mutual influence of these two systems in the regulation of CNS functions. These new ways of understanding this interaction are of utmost importance to envision the consequences of their dysfunctions underlined in several CNS diseases. It is also essential to conceive the mechanism of action of psychotropic drugs directly acting on their function including antipsychotic, antidepressant, antiparkinsonian, and drug of abuse together with the development of therapeutic strategies of Alzheimer's diseases, epilepsy, obsessional compulsive disorders. The 5-HT/DA interaction has a long history from the serendipitous discovery of antidepressants and antipsychotics to the future, rationalized treatments of CNS disorders.

Sequential One-Pot Synthesis of 3-Arylbenzofurans from N-Tosylhydrazones and Bromophenol Derivatives

A divergent and efficient one-pot sequence allowing direct access to 3-arylbenzofuran derivatives has been developed. The process, involving N-tosylhydrazones and bromophenols, proceeds via a palladium-catalyzed Barluenga-Valdés cross-coupling, followed by an aerobic, copper-catalyzed, radical cyclization to form Csp²-Csp² and O-Csp² bonds. 3-Arylated benzofurans bearing various substituents were obtained with good to excellent yields (up to 90%). Mechanistic investigation strongly supports a radical process for the cyclization step.

The Multimodal Serotonergic Agent Vilazodone Inhibits L-DOPA-Induced Gene Regulation in Striatal Projection Neurons and Associated Dyskinesia in an Animal Model of Parkinson's Disease

Levodopa (L-DOPA) treatment in Parkinson's disease is limited by the emergence of L-DOPA-induced dyskinesia. Such dyskinesia is associated with aberrant gene regulation in neurons of the striatum, which is caused by abnormal dopamine release from serotonin terminals. Previous work showed that modulating the striatal serotonin innervation with selective serotonin reuptake inhibitors (SSRIs) or 5-HT1A receptor agonists could attenuate L-DOPA-induced dyskinesia. We investigated the effects of a novel serotonergic agent, vilazodone, which combines SSRI and 5-HT1A partial agonist properties, on L-DOPA-induced behavior and gene regulation in the striatum in an animal model of Parkinson's disease. After unilateral dopamine depletion by 6-hydroxydopamine (6-OHDA), rats received repeated L-DOPA treatment (5 mg/kg) alone or in combination with vilazodone (10 mg/kg) for 3 weeks. Gene regulation was then mapped throughout the striatum using in situ hybridization histochemistry. Vilazodone suppressed the development of L-DOPA-induced dyskinesia and turning behavior but did not interfere with the prokinetic effects of L-DOPA (forelimb stepping). L-DOPA treatment drastically increased the expression of dynorphin (direct pathway), 5-HT1B, and zif268 mRNA in the striatum ipsilateral to the lesion. These effects were inhibited by vilazodone. In contrast, vilazodone had no effect on enkephalin expression (indirect pathway) or on gene expression in the intact striatum. Thus, vilazodone inhibited L-DOPA-induced gene regulation selectively in the direct pathway of the dopamine-depleted striatum, molecular changes that are considered critical for L-DOPA-induced dyskinesia. These findings position vilazodone, an approved antidepressant, as a potential adjunct medication for the treatment of L-DOPA-induced motor side effects.

Functional characterization of 5-HT1A and 5-HT1B serotonin receptor signaling through G-protein-activated inwardly rectifying K+ channels in a fluorescence-based membrane potential assay

The 5-HT_1A and 5-HT_1B serotonin receptors are abundantly expressed in the CNS and constitute validated as well as putative drug targets in a variety of psychiatric and cognitive disorders, alcoholism/addiction, pain and migraine. In the present study we have characterized the functional properties of human 5-HT_1A and 5-HT_1B stably co-expressed with the human G-protein-activated inwardly rectifying K⁺ channel 2 (GIRK2) in HEK293 cells in the fluorescence-based FLIPR® Membrane Potential Blue (FMP) assay. Serotonin and other agonists induced robust decreases in fluorescence levels in the 5-HT_1A/GIRK2- and 5-HT_1B/GIRK2-HEK293 cells in a concentration-dependent manner in the assay, and these responses could be inhibited by selective 5-HT_1A/5-HT_1B antagonists and by the Gα_i/o-protein inhibitor pertussis toxin (PTX). Five additional stable HEK293 cell lines co-expressing 5-HT_1A or 5-HT_1B with GIRK2 and one of the PTX-insensitive Gα_i/o-subunit mutants Gα_i1^C351I, Gα_i2^C352I and Gα_o1^C351I were constructed, and 5-HT_1A/5-HT_1B-mediated responses through these specific Gα_i/o-subunits were measured in these cells pretreated with PTX in the FMP assay. The functional properties of 16 reference 5-HT₁ agonists were characterized at the seven cell lines, which constitutes the most detailed pharmacological profiling and comparison of 5-HT_1A and 5-HT_1B receptor signaling in the same assay published to date. We propose that this approach to assay 5-HT₁-mediated signaling through endogenous Gα_i/o-proteins in HEK293 cells or through specific Gα_i/o-subunits in a fairly high-throughput manner holds some advantages to other functional assays for Gα_i/o-coupled receptors. The assay will facilitate detailed profiling of the Gα_i/o- and Gβγ-mediated signaling of 5-HT_1A and 5-HT_1B at the molecular level, and it could also be used to identify novel modulators for the receptors.

The binding mode of vilazodone in the human serotonin transporter elucidated by ligand docking and molecular dynamics simulations

Vilazodone is a novel antidepressant used for the treatment of major depressive disorder (MDD) with a primary action mechanism of inhibiting the human serotonin reuptake transporter (hSERT) and acting as a 5-HT_1A receptor partial agonist. The interaction between vilazodone and the 5-HT_1A receptor has been reported, however, the binding mode of vilazodone in the hSERT remains elusive. In the current study, to elucidate the molecular mechanism of vilazodone binding in the hSERT, the drug and its five analogs were docked into the hSERT crystal structure as initial conformations and were sampled by 400 ns molecular dynamics (MD) simulations. Through the analysis of the profiles of protein-ligand binding free energies, interaction fingerprints, and conformational rearrangements, the binding mode of vilazodone in the hSERT was revealed. As a result, unlike the classical antidepressants located in the S1 site of the hSERT, vilazodone adopted a linear pose in the binding pocket. Its arylpiperazine fragment occupies the central site (S1) and interacts with Y95, D98, I172, Y176, F335, F341, S438, and T439, while the indole fragment extends to the allosteric site (S2) via interacting with the ionic switch (R104/E403) between the two sites. The new insights obtained are not only helpful in understanding the binding mode of vilazodone in the hSERT, but also provide valuable guidance to the discovery of novel antidepressant drugs.

Behavioral effects of buspirone in a mouse model of posttraumatic stress disorder

Buspirone presents a unique profile of action, which involves activation of 5-HT_1A receptors and complex effects on D₂-like dopaminergic receptors. This medication is studied in terms of potential clinical repositioning to conditions that are associated with dopaminergic dysfunctions including schizophrenia and substance use disorder. Buspirone antagonizes D₃ and D₄ receptors, however, depending on the dose it differentially interacts with D₂ receptors. Previously, we reported that some of D₂/D₃ dopaminergic agonists attenuate PTSD-like behavioral symptoms in mice. Here we investigated whether buspirone could also affect PTSD-like symptoms. We used the single prolonged stress (mSPS) protocol to induce PTSD-like behavior in adult male CD-1 mice. Buspirone (0.5, 2, or 10 mg/kg, i.p.) was injected for 15 consecutive days. The subjects were repeatedly examined in a variety of behavioral tests measuring conditioned freezing response, antidepressant-like effects, anxiety, and ultrasonic vocal response to the restraint stress. Mouse SPS resulted in prolonged immobility in the forced swim test and freezing in the fear-conditioning test, and produced symptoms of anxiety. Buspirone dose-dependently decreased the exaggerated freezing response in mice, but only at the dose of 2 mg/kg exhibited the anxiolytic-like effect in the elevated plus maze test. Buspirone reduced the number of ultrasonic calls in mSPS-exposed mice but revealed no antidepressant-like effect in the forced swim test. Present data suggest some positive effects of buspirone in the treatment of selected PTSD-like symptoms and prompt for its further clinical evaluation.

New Treatment Options for Depression: A Primer for Internists

Depression continues to be a challenging condition to treat despite the myriad treatment options available. Primary care providers are increasingly tasked with providing second- and third-line treatments for major depressive disorder, and thus, should be familiar with newer medication therapies that are available. In this article, we aim to provide the general internist and other providers who treat depression in their practice with a succinct review of recent developments in the treatment of depression.

Substrate and inhibitor binding to the serotonin transporter: Insights from computational, crystallographic, and functional studies

The serotonin transporter (SERT) belongs to the monoamine transporter family, which also includes the dopamine and norepinephrine transporters. SERT is essential for regulating serotonergic signaling by the reuptake of serotonin from the synaptic cleft back into the presynaptic neuron. Dysregulation of SERT has been implicated in several major psychiatric disorders such as major depressive disorder (MDD). MDD was among the top five leading causes of years lived with disease in 2016 and is characterized as a major global burden. Several drugs have been developed to target SERT for use in the treatment of MDD, and their respective binding modes and locations within SERT have been studied. The elucidation of the first structure of a bacterial SERT homologue in 2005 has accelerated crystallographic, computational, and functional studies to further elucidate drug binding and method of action in SERT. Herein, we aim to highlight and compare these studies with an emphasis on what the different experimental methods conclude on substrate and inhibitor binding modes, and the potential caveats of using the different types of studies are discussed. We focus this review on the binding of cognate substrate and drugs belonging to the different families of antidepressants, including tricyclic antidepressants, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and multimodal drugs, as well as illicit drugs such as cocaine, amphetamines, and ibogaine. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.

Molecular aspects of depression: A review from neurobiology to treatment

Major depressive disorder (MDD), also known as unipolar depression, is one of the leading causes of disability and disease worldwide. The signs and symptoms are low self‑esteem, anhedonia, feeling of worthlessness, sense of rejection and guilt, suicidal thoughts, among others. This review focuses on studies with molecular-based approaches involving MDD to obtain an integrated, more detailed and comprehensive view of the brain changes produced by this disorder and its treatment and how the Central Nervous System (CNS) produces neuroplasticity to orchestrate adaptive defensive behaviors. This article integrates affective neuroscience, psychopharmacology, neuroanatomy and molecular biology data. In addition, there are two problems with current MDD treatments, namely: 1) Low rates of responsiveness to antidepressants and too slow onset of therapeutic effect; 2) Increased stress vulnerability and autonomy, which reduces the responses of currently available treatments. In the present review, we encourage the prospection of new bioactive agents for the development of treatments with post-transduction mechanisms, neurogenesis and pharmacogenetics inducers that bring greater benefits, with reduced risks and maximized access to patients, stimulating the field of research on mood disorders in order to use the potential of preclinical studies. For this purpose, improved animal models that incorporate the molecular and anatomical tools currently available can be applied. Besides, we encourage the study of drugs that do not present "classical application" as antidepressants, (e.g., the dissociative anesthetic ketamine and dextromethorphan) and drugs that have dual action mechanisms since they represent potential targets for novel drug development more useful for the treatment of MDD.

Evaluation of vilazodone for the treatment of depressive and anxiety disorders

INTRODUCTION

Major Depressive Disorder (MDD) and General Anxiety Disorder (GAD) significantly contribute to the global burden of disease. Vilazodone, a combined serotonin reuptake inhibitor and 5-HT1A partial agonist, is an approved therapy for the treatment of MDD and which has been further investigated for GAD. Areas covered: This article covers the pharmacokinetics and pharmacodynamics of vilazodone and provides an evaluation of the clinical usefulness of vilazodone for the treatment of MDD and anxiety disorders. A literature search was performed using PubMed/MEDLINE, Web of Science and the Cochrane Library. Expert opinion: Studies have shown that vilazodone is significantly superior to placebo. However, vilazodone cannot as yet be recommended as a first-line treatment option for MDD as it is unclear whether the drug's dual mechanism of action provides greater efficacy than prevailing treatment options. Moreover, more phase IV studies are needed to establish its efficacy and long-term safety in larger and more diverse populations. Although vilazodone may have an additional advantage for the treatment of anxiety symptoms in MDD, here also additional studies are required to confirm its efficacy over and above SSRI alternatives and other antidepressant treatments. Therefore, presently, vilazodone should be considered as a second- or third-line treatment option for MDD and GAD.

Efficacy and tolerability of different doses of three new antidepressants for treating major depressive disorder: A PRISMA-compliant meta-analysis

In last decade, the US FDA has approved three new antidepressants: vortioxetine, levomilnacipran, and vilazodone. Many studies have researched the effects of these antidepressants on major depressive disorder (MDD), but they have not determined the optimum dosage. This meta-analysis investigated the efficacies of these three drugs at different dosages in the treatment of MDD. The PubMed, Embase, Cochrane Library, psycINFO, and ClinicalTrials.gov databases were searched to identify relevant literature. The primary outcomes were efficacy [quantified as the change from baseline in total score on the Montgomery-Asberg Depression Rating Scale (MADRS)] and tolerability (discontinuations due to adverse events). The effect size was quantified as the weighted mean difference for continuous data and the risk ratio (RR) for dichotomous data. Overall 22 studies were included. The changes in the MADRS total score were significantly higher for vortioxetine at 5, 10, 20, and 10-20 mg/day than for placebo. The tolerability was significantly worse for 20 mg/day vortioxetine than for placebo (RR = 1.84, 95% confidence interval = 1.13 to 3.02). In addition, increasing the dosage improved the efficacy of vortioxetine but worsened the tolerability. Levomilnacipran and vilazodone at any dosage produced a significantly higher mean change from baseline in the MADRS total score and a worse tolerability than for placebo. In conclusion, considering both efficacy and tolerability, 10 mg/day vortioxetine might be optimal for the treatment of MDD. The long-term efficacy and safety of vortioxetine needed to be investigated, and more studies of levomilnacipran and vilazodone are needed to define their optimal dosages.

Identification and characterization of vilazodone metabolites in rats and microsomes by ultrahigh-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry

RATIONALE

Vilazodone is a selective serotonin reuptake inhibitor (SSRI) used for the treatment of major depressive disorder (MDD). An extensive literature search found few reports on the in vivo and in vitro metabolism of vilazodone. Therefore, we report a comprehensive in vivo and in vitro metabolic identification and structural characterization of vilazodone using ultrahigh-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF/MS/MS) and in silico toxicity study of the metabolites.

METHODS

To identify in vivo metabolites of vilazodone, blood, urine and faeces samples were collected at different time intervals starting from 0 h to 48 h after oral administration of vilazodone to Sprague-Dawley rats. The in vitro metabolism study was conducted with human liver microsomes (HLM) and rat liver microsomes (RLM). The samples were prepared using an optimized sample preparation approach involving protein precipitation followed by solid-phase extraction. The metabolites have been identified and characterized by using LC/ESI-MS/MS.

RESULTS

A total of 12 metabolites (M1-M12) were identified in in vivo and in vitro matrices and characterized by LC/ESI-MS/MS. The majority of the metabolites were observed in urine, while a few metabolites were present in faeces and plasma. Two metabolites were observed in the in vitro study. A semi-quantitative study based on percentage counts shows that metabolites M11, M6 and M8 were observed in higher amounts in urine, faeces and plasma, respectively.

CONCLUSIONS

The structures of all the 12 metabolites were elucidated by using LC/ESI-MS/MS. The study suggests that vilazodone was metabolized via hydroxylation, dihydroxylation, glucuronidation, oxidative deamination, dealkylation, dehydrogenation and dioxidation. All the metabolites were screened for toxicity using an in silico tool.

The frontal cortex as a network hub controlling mood and cognition: Probing its neurochemical substrates for improved therapy of psychiatric and neurological disorders

The highly-interconnected and neurochemically-rich frontal cortex plays a crucial role in the regulation of mood and cognition, domains disrupted in depression and other central nervous system disorders, and it is an important site of action for their therapeutic control. For improving our understanding of the function and dysfunction of the frontal cortex, and for identifying improved treatments, quantification of extracellular pools of neuromodulators by microdialysis in freely-moving rodents has proven indispensable. This approach has revealed a complex mesh of autoreceptor and heteroceptor interactions amongst monoaminergic pathways, and led from selective 5-HT reuptake inhibitors to novel classes of multi-target drugs for treating depression like the mixed α₂-adrenoceptor/5-HT reuptake inhibitor, S35966, and the clinically-launched vortioxetine and vilazodone. Moreover, integration of non-monoaminergic actions resulted in the discovery and development of the innovative melatonin receptor agonist/5-HT_2C receptor antagonist, Agomelatine. Melatonin levels, like those of corticosterone and the "social hormone", oxytocin, can now be quantified by microdialysis over the full 24 h daily cycle. Further, the introduction of procedures for measuring extracellular histamine and acetylcholine has provided insights into strategies for improving cognition by, for example, blockade of 5-HT₆ and/or dopamine D₃ receptors. The challenge of concurrently determining extracellular levels of GABA, glutamate, d-serine, glycine, kynurenate and other amino acids, and of clarifying their interactions with monoamines, has also been resolved. This has proven important for characterizing the actions of glycine reuptake inhibitors that indirectly augment transmission at N-methyl-d-aspartate receptors, and of "glutamatergic antidepressants" like ketamine, mGluR5 antagonists and positive modulators of AMPA receptors (including S47445). Most recently, quantification of the neurotoxic proteins Aβ42 and Tau has extended microdialysis studies to the pathogenesis of neurodegenerative disorders, and another frontier currently being broached is microRNAs. The present article discusses the above themes, focusses on recent advances, highlights opportunities for clinical "translation", and suggests avenues for further progress.

Vilazodone for the Treatment of Depression: An Update

Vilazodone is a novel antidepressant having a selective serotonin (5-HT) reuptake inhibitor and 5-HT1A receptor partial agonist profile, so it has been regarded as a serotonin partial agonist-reuptake inhibitor (SPARI). We aimed to provide Vilazodone's clinical implications mainly by reviewing published clinical trials. Vilazodone has been speculated to have three potential benefits including faster onset of action, greater efficacy, and better tolerability owning to its SPARI properties. However, no studies conducted so far have directly proven the above speculations. Five initial phase II trials failed to distinguish vilazodone from placebo in the treatment of MDD, but 4 randomized clinical trials (RCT), 3 post-hoc or pooled analysis, 1 long-term open label study, and a meta-analysis showed vilazodone's superior efficacy over placebo. The studies also showed vilazodone is generally safe and tolerable. However, diarrhea, nausea, headache, dizziness, dry mouth, and insomnia warrant close attention in clinical practice because they have been constantly noted throughout the clinical studies. 2 RCTs recently documented the efficacy and safety of vilazodone in patients with generalized anxiety disorder, which could be a start of broadening vilazodone's usage or FDA approval in diverse anxiety disorders.

The Preclinical and Clinical Effects of Vilazodone for the Treatment of Major Depressive Disorder

INTRODUCTION

Major depressive disorder (MDD) is the leading cause of disability worldwide, and according to the STAR*D trial, only 33% of patients with MDD responded to initial drug therapy. Augmentation of the leading class of antidepressant treatment, selective serotonin reuptake inhibitors (SSRIs), with the 5-HT1A receptor agonist buspirone has been shown to be effective in treating patients that do not respond to initial SSRI therapy. This suggests that newer treatments may improve the clinical picture of MDD. The US Food and Drug Administration (FDA) approved the antidepressant drug vilazodone (EMD 68843), a novel SSRI and 5-HT1A receptor partial agonist. Vilazodone has a half-life between 20-24 hours, reaches peak plasma concentrations at 3.7-5.3 hours, and is primarily metabolized by the hepatic CYP450 3A4 enzyme system.

AREAS COVERED

The authors review the preclinical and clinical profile of vilazodone. The roles of serotonin, the 5-HT1A receptor, and current pharmacotherapy approaches for MDD are briefly reviewed. Next, the preclinical pharmacological, behavioral, and physiological effects of vilazodone are presented, followed by the pharmacokinetic properties and metabolism of vilazodone in humans. Last, a brief summary of the main efficacy, safety, and tolerability outcomes of clinical trials of vilazodone is provided.

EXPERT OPINION

Vilazodone has shown efficacy versus placebo in improving depression symptoms in several double-blind, placebo-controlled trials. The long-term safety and tolerability of vilazodone treatment has also been established. Further studies are needed that directly compare patients treated with an SSRI (both with and without an adjunctive 5-HT1A partial agonist) versus patients treated with vilaozodone.

Differential effects of vilazodone versus citalopram and paroxetine on sexual behaviors and serotonin transporter and receptors in male rats

RATIONALE

Sexual side effects are commonly associated with selective serotonin reuptake inhibitor (SSRI) treatment. Some evidence suggest that activation of 5-HT1A receptors attenuates SSRI-induced sexual dysfunction.

OBJECTIVE

This study in male rats compared the effects of vilazodone, an antidepressant with SSRI and 5-HT1A receptor partial agonist activity, with other prototypical SSRIs (citalopram and paroxetine) on sexual behaviors and 5-HT receptors (5-HT1A and 5-HT2A) and transporter (5-HTT) levels in select forebrain regions of the limbic system using quantitative autoradiography.

METHODS

Rats received vilazodone (1, 3, and 10 mg/kg), citalopram (10 and 30 mg/kg), or paroxetine (10 mg/kg) treatment for 14 days. Sexual behaviors (frequency and latency of mounts, intromissions, and ejaculations) were measured in the presence of an estrous female rat on days 1 (acute), 7 (subchronic), and 14 (chronic).

RESULTS

Vilazodone-treated rats exhibited no sexual dysfunction compared with controls; in contrast, the citalopram- and paroxetine-treated rats exhibited impaired copulatory and ejaculatory behaviors after subchronic and chronic treatments. Chronic vilazodone treatment markedly decreased 5-HT1A receptor levels in cortical and hippocampal regions, while the SSRIs increased levels of this receptor in similar regions. All chronic treatments reduced 5-HTT levels across the forebrain; however, the magnitude of the decrease was considerably smaller for vilazodone than for the SSRIs.

CONCLUSIONS

The current studies showed that chronic treatment with vilazodone, in contrast to citalopram and paroxetine, was not associated with diminished sexual behaviors in male rats, which may be related to the differential effects of vilazodone on 5-HT1A receptor and 5-HTT levels relative to conventional SSRIs.

Serotonergic Regulation of Prefrontal Cortical Circuitries Involved in Cognitive Processing: A Review of Individual 5-HT Receptor Mechanisms and Concerted Effects of 5-HT Receptors Exemplified by the Multimodal Antidepressant Vortioxetine

It has been known for several decades that serotonergic neurotransmission is a key regulator of cognitive function, mood, and sleep. Yet with the relatively recent discoveries of novel serotonin (5-HT) receptor subtypes, as well as an expanding knowledge of their expression level in certain brain regions and localization on certain cell types, their involvement in cognitive processes is still emerging. Of particular interest are cognitive processes impacted in neuropsychiatric and neurodegenerative disorders. The prefrontal cortex (PFC) is critical to normal cognitive processes, including attention, impulsivity, planning, decision-making, working memory, and learning or recall of learned memories. Furthermore, serotonergic dysregulation within the PFC is implicated in many neuropsychiatric disorders associated with prominent symptoms of cognitive dysfunction. Thus, it is important to better understand the overall makeup of serotonergic receptors in the PFC and on which cell types these receptors mediate their actions. In this Review, we focus on 5-HT receptor expression patterns within the PFC and how they influence cognitive behavior and neurotransmission. We further discuss the net effects of vortioxetine, an antidepressant acting through multiple serotonergic targets given the recent findings that vortioxetine improves cognition by modulating multiple neurotransmitter systems.

DSP-1053, a novel serotonin reuptake inhibitor with 5-HT1A partial agonistic activity, displays fast antidepressant effect with minimal undesirable effects in juvenile rats

Enhancement of serotonergic neurotransmission has been the main stream of treatment for patients with depression. However, delayed therapeutic onset and undesirable side effects are major drawbacks for conventional serotonin reuptake inhibitors. Here, we show that DSP-1053, a novel serotonin reuptake inhibitor with 5-HT_1A partial agonistic activity, displays fast antidepressant efficacy with minimal undesirable effects, especially nausea and emesis in animal models. DSP-1053 bound human serotonin transporter and 5-HT_1A receptor with the K_i values of 1.02 ± 0.06 and 5.05 ± 1.07 nmol/L, respectively. This compound inhibited the serotonin transporter with an IC₅₀ value of 2.74 ± 0.41 nmol/L and had an intrinsic activity for 5-HT_1A receptors of 70.0 ± 6.3%. In rat microdialysis, DSP-1053, given once at 3 and 10 mg kg⁻¹, dose-dependently increased extracellular 5-HT levels. In the rat forced swimming test, 2-week administration of DSR-1053 (1 mg kg⁻¹) significantly reduced rats immobility time after treatment, whereas paroxetine (3 and 10 mg kg⁻¹) required 3-week administration to reduce rats immobility time. In olfactory bulbectomy model, 1- and 2-week administration of DSP-1053 reduced both of emotional scores and activity in the open field, whereas paroxetine required 2 weeks to show similar beneficial effects. Although single administration of DSP-1053-induced emesis and vomiting in the rat and Suncus murinus, multiple treatment with this compound, but not with paroxetine, decreased the number of vomiting episodes. These results highlight the important role of 5-HT_1A receptors in both the efficacy and tolerability of DSP-1053 as a new therapeutic option for the treatment of depression.

Vilazodone for the treatment of major depressive disorder: an evidence-based review of its place in therapy

INTRODUCTION

It has clearly been demonstrated that depressive disorders constitute a major worldwide public health problem, with massive economic and quality-of-life consequences. Existing pharmacological treatments have limited efficacy, with only about a third of patients achieving remission on any one medication. Delayed onset of action and variable tolerability contribute to this limited efficacy. Vilazodone, introduced in the US in 2011, has been described as the first member of the serotonin partial agonist-reuptake inhibitor (SPARI) class of medications, combining serotonin-reuptake inhibition with 5-HT1A partial agonism. This agent could potentially have benefits for subgroups of depressed patients, including depressed patients with comorbid anxiety and patients with anxiety disorders, and might have fewer sexual side effects than selective serotonin-reuptake inhibitors (SSRIs).

AIMS

We reviewed existing clinical trials that assess the benefits of vilazodone for treatment of major depression.

EVIDENCE REVIEW

In clinical trials, including two Phase III studies and two Phase IV studies, vilazodone has been shown to have efficacy greater than placebo on the Montgomery-Åsberg Depression Rating Scale, comparable efficacy to citalopram, and continued benefit after 52 weeks of treatment. The safety profile for vilazodone is comparable to other SSRI medications, and tolerability also appears generally comparable to other SSRI medications.

PLACE IN THERAPY

Vilazodone, which has been described as the first-of-class SPARI medication, may potentially have benefits for subgroups of patients, particularly those depressed individuals with coexisting anxiety symptoms or anxiety disorders. However, convincing evidence for these benefits has as yet not been published.

Vilazodone for the treatment of major depressive disorder: focusing on its clinical studies and mechanism of action

We tried to review and update clinical and preclinical studies evaluating vilazodone's role as an antidepressant for patients with major depressive disorder (MDD). In terms of its mechanism of actions, we sought to elaborate them mainly through preclinical animal studies. A data search was conducted in November 1, 2013, using the key terms "vilazodone" or "Viibryd," in PubMed and Medline databases. All published and unpublished studies are included and citations from publications were also reviewed for additional references. Five unpublished, phase-II and two pivotal published phase-III clinical trials with nearly identical design (8-week, double-blind, randomized, and placebo-controlled) investigated efficacy of vilazodone, were found for the treatment of patients with MDD. Two post-hoc studies and one long-term open study were also included. Data were thoroughly reviewed to incorporate the pharmacology, action mechanism, efficacy and safety for the vilazodone in the treatment of major depressive disorder. Vilazodone is an antidepressant with novel mechanism of action because its chemical structure is unrelated to conventional antidepressant, and it has a selective serotonin (5-HT) reuptake inhibitor and 5-HT1A receptor partial agonist profile. Vilazodone is an effective and safe treatment option with its novel action mechanisms for patients with depression. Its putative benefits compared with other antidepressants must be thoroughly studied in adequately-powered and well-designed future clinical trials.

Health resource use and costs of vilazodone and other selective serotonin re-uptake inhibitors in treating major depressive disorder

OBJECTIVE

Selective serotonin re-uptake inhibitors (SSRIs) are widely prescribed antidepressants. This claims database study compared healthcare resource use and costs among patients with major depressive disorder (MDD) treated with vilazodone vs other SSRIs.

METHODS

Adults with an MDD diagnosis and ≥ 1 prescription fill for vilazodone, citalopram, escitalopram, fluoxetine, paroxetine, or sertraline were identified from administrative claims data (2010-2012). Patients who concomitantly used adjunctive medication, either a second-generation antidepressant or antipsychotic, were excluded. All-cause and MDD-related healthcare resource use and costs (in 2012 USD) were compared between patients treated with vilazodone vs other SSRIs over a 6-month follow-up period using unadjusted and multivariable analyses.

RESULTS

The study cohort included 49 861 patients (mean age = 44.0 years; 70% female). Compared with the vilazodone cohort (n = 3527), patients in the citalopram (n = 12 187), escitalopram (n = 8275), fluoxetine (n = 10 142), paroxetine (n = 3146), and sertraline (n = 12 584) cohorts had significantly more all-cause inpatient hospital visits, longer hospital stays and more frequent emergency department visits, following the index date, after adjusting for baseline characteristics. All-cause medical service costs (inpatient + outpatient + emergency department visits) were significantly higher across all other SSRI cohorts vs vilazodone by $758-$1165 (p < 0.05). Similarly, all-cause total costs, were significantly or numerically (non-significantly) higher across all SSRI cohorts vs vilazodone by $351-$780.

LIMITATIONS

The was no clinical measurement of disease severity, partial coverage of the Medicare-eligible population, and short follow-up.

CONCLUSION

MDD treatment with vilazodone was associated with significantly lower rates of inpatient and emergency services, and with significantly lower all-cause medical service costs and numerically (non-significantly) lower total costs to payers than with the other SSRIs included in this study.

Evaluation of the efficacy and safety of vilazodone for treating major depressive disorder

PURPOSE

Vilazodone is a novel serotonin (5-HT)-reuptake inhibitor and 5-HT1A partial agonist that was recently developed for the treatment of major depressive disorder (MDD). We conducted a meta-analysis and systematic review to better evaluate the efficacy and safety of vilazodone.

MATERIALS AND METHODS

We performed a thorough literature search to identify all randomized double-blind placebo-controlled trials that were designed to investigate the efficacy of vilazodone for the treatment of MDD, and that were published in electronic databases, including Medline, Embase, and the Cochrane Central Register of Controlled Trials. A manual search was also conducted to investigate the relevant references of the retrieved studies. Subsequently, we conducted a meta-analysis and systematic literature review.

RESULTS

A total of five randomized controlled trials were finally included, involving 1,200 patients with vilazodone and 1,193 patients with placebo. The primary efficacy end point of the Montgomery-Åsberg Depression Rating Scale (standardized mean difference -3.58, 95% confidence interval -4.59 to -2.56; P<0.00001), and the key secondary efficacy end points (Clinical Global Impression - Severity scale, Clinical Global Impression - Improvement scale, and Hamilton Anxiety Rating Scale) indicated that vilazodone was more effective than placebo. Most common adverse events, including diarrhea and nausea, were evaluated, and safety assessments indicated that vilazodone was well tolerated (diarrhea odds ratio 3.54, 95% confidence interval 2.81-4.45; P<0.00001; nausea odds ratio 3.85, 95% confidence interval 3.00-4.96; P<0.00001; discontinuations due to adverse events odds ratio 2.71, 95% confidence interval 1.81-4.05; P<0.00001).

CONCLUSION

Our findings indicate that the novel antidepressant vilazodone is effective and safe for MDD, with a low occurrence of side effects. It offers promise as an effective oral drug for the treatment of MDD, with a balance of efficacy and tolerability.

A review of the clinical efficacy, safety and tolerability of the antidepressants vilazodone, levomilnacipran and vortioxetine

INTRODUCTION

As a leading cause of disability, major depressive disorder (MDD) is characterized by reduced quality of life and altered functioning. Current pharmaceutical treatment options are limited in their success by modest effects and adverse events that often lead to discontinuation. One current trend in antidepressant development is to combine inhibition of the serotonin transporter with other pharmacological targets, including the norepinephrine transporter or different serotonin receptors.

AREAS COVERED

In a span of < 3 years, the FDA approved three new antidepressants for the treatment of MDD: vilazodone in January 2011, levomilnacipran in July 2013 and vortioxetine in September 2013. This article reviews the efficacy, safety and tolerability of these three drugs mainly from the Phase III trial data.

EXPERT OPINION

All three drugs are effective in the treatment of MDD, but data comparing them to other antidepressants is currently lacking. Vilazodone was proposed to produce a more rapid onset and have fewer sexual side effects but neither effect has been conclusively shown. Levomilnacipran appears to be effective in improving functional impairment, including both social and work functioning. Vortioxetine is currently the only drug of the three with proven efficacy in elderly patients. It also appears to have cognitive enhancing properties which are largely independent of improved depressive symptoms. Overall, these drugs represent a promising step forward in antidepressant drug development.