Discontinuation of medications classified as reuptake inhibitors affects treatment response of MDMA-assisted psychotherapy.

RATIONALE: MDMA-assisted psychotherapy is under investigation as a novel treatment for posttraumatic stress disorder (PTSD). The primary mechanism of action of MDMA involves the same reuptake transporters targeted by antidepressant medications commonly prescribed for PTSD. OBJECTIVES: Data were pooled from four phase 2 trials of MDMA-assisted psychotherapy. To explore the effect of tapering antidepressant medications, participants who had been randomized to receive active doses of MDMA (75-125 mg) were divided into two groups (taper group (n = 16) or non-taper group (n = 34)). METHODS: Between-group comparisons were made for PTSD and depression symptom severity at the baseline and the primary endpoint, and for peak vital signs across two MDMA sessions. RESULTS: Demographics, baseline PTSD, and depression severity were similar between the taper and non-taper groups. At the primary endpoint, the non-taper group (mean = 45.7, SD = 27.17) had a significantly (p = 0.009) lower CAPS-IV total scores compared to the taper group (mean = 70.3, SD = 33.60). More participants in the non-taper group (63.6%) no longer met PTSD criteria at the primary endpoint than those in the taper group (25.0%). The non-taper group (mean = 12.7, SD = 10.17) had lower depression symptom severity scores (p = 0.010) compared to the taper group (mean = 22.6, SD = 16.69). There were significant differences between groups in peak systolic blood pressure (p = 0.043) and diastolic blood pressure (p = 0.032). CONCLUSIONS: Recent exposure to antidepressant drugs that target reuptake transporters may reduce treatment response to MDMA-assisted psychotherapy.

Effects of monoamine depletion on the ketamine-induced locomotor activity of preweanling, adolescent, and adult rats: Sex and age differences.

Ketamine significantly increases the locomotor activity of rodents, however this effect varies according to the sex and age of the animal being tested. To determine the role monoamine systems play in ketamine's locomotor activating effects: (a) male and female preweanling, adolescent, and adult rats were pretreated with vehicle or the monoamine depleting agent reserpine (1 or 5 mg/kg), and (b) the behavioral actions of ketamine (20 or 40 mg/kg) were then compared to d-amphetamine (2 mg/kg) and cocaine (10 or 15 mg/kg). The ability of reserpine to deplete dorsal striatal dopamine (DA) and serotonin (5-HT) in male and female rats was determined using HPLC. Ketamine caused substantial increases in the locomotion of preweanling rats and older female rats (adolescents and adults), but had only small stimulatory effects on adolescent and adult male rats. When compared to cocaine and d-amphetamine, ketamine was especially sensitive to the locomotor-inhibiting effects of monoamine depletion. Ketamine-induced locomotion is at least partially mediated by monoamine systems, since depleting DA and 5-HT levels by 87-96% significantly attenuated the locomotor activating effects of ketamine in male and female rats from all three age groups. When administered to reserpine-pretreated rats, ketamine produced a different pattern of behavioral effects than either psychostimulant, suggesting that ketamine does not stimulate locomotor activity via actions at the presynaptic terminal. Instead, our results are consistent with the hypothesis that ketamine increases locomotor activity through a down-stream mechanism, possibly involving ascending DA and/or 5-HT projection neurons.

Dopamine and norepinephrine transporter inhibition for long-term fear memory enhancement.

Psychostimulants are highly effective cognitive-enhancing therapeutics yet have a significant potential for abuse and addiction. While psychostimulants likely exert their rewarding and addictive properties through dopamine transporter (DAT) inhibition, the mechanisms of their procognitive effects are less certain. By one prevalent view, psychostimulants exert their procognitive effects exclusively through norepinephrine transporter (NET) inhibition, however increasing evidence suggests that DAT also plays a critical role in their cognitive-enhancing properties, including long-term memory enhancement. The present experiments test the hypothesis that combined strong NET and weak DAT inhibition will mimic the fear memory-enhancing but not the addiction-related effects of psychostimulants in mice. We examined the effects of the high affinity NET inhibitors atomoxetine or nisoxetine and the low affinity DAT inhibitor bupropion, either alone or in combination, on short- and long-term memory of Pavlovian fear conditioning. We also examined the addiction-related effects of combined strong NET and weak DAT inhibition using conditioned place preference and a locomotor activity test. While atomoxetine or nisoxetine alone enhanced short-term fear memory, the addition of bupropion was required to significantly enhance long-term fear memory. Additionally, combined atomoxetine and bupropion did not produce substantial motor stimulation or place preference. These findings suggest that combining strong NET and weak DAT inhibition could lead to the development of a highly effective cognitive enhancer that lacks the potential for addiction.

Solriamfetol: First Global Approval.

Solriamfetol (Sunosi™) is an orally active, selective dopamine and norepinephrine reuptake inhibitor that was recently approved in the USA as a treatment for excessive daytime sleepiness (hypersomnia) associated with narcolepsy and obstructive sleep apnoea (OSA). Norepinephrine and dopamine influence various physiologic functions, including sleep-wake regulation, and excessive sleepiness has been linked with dysregulation of dopaminergic and norepinephrine systems. This article summarizes the milestones in the development of solriamfetol leading to this first approval as a treatment for excessive daytime sleepiness associated with narcolepsy and OSA.

BDNF mediates the protective effects of scopolamine in reserpine-induced depression-like behaviors via up-regulation of 5-HTT and TPH1.

Reserpine treatment in rodents has been shown to induce depression-like behaviors that mimic monoamine dysfunction implicated in the development of depression. Herein, we aimed to demonstrate the antidepressant-like activities of scopolamine, the muscarinic receptor antagonist, in a reserpine-induced mouse model. Mice were injected with 1.5 mg/kg (i.p.) of reserpine for 10 days, and the depression-like state was confirmed via the open field test (OFT) and forced swimming test (FST). Then, the mice were treated with scopolamine (25 µg/kg, i.p.) or saline for 3 days. Ten days of reserpine treatment resulted in a significant decrease in locomotor activity and an increase in immobility time in the OFT and FST, respectively, indicating that ten days of reserpine administration significantly induced depression-like behaviors in mice. However, scopolamine rapidly ameliorated the increase in immobility time in the FST and had no effect on locomotor activity in the OFT. In addition, the reserpine-induced decreases in serotonin transporter (5-HTT), brain-derived neurotrophic factor (BDNF) and tryptophan hydroxylase 1 (TPH1) in mouse hippocampus and prefrontal cortex (PFC) were significantly reversed by scopolamine. Our study provides evidence that scopolamine rapidly attenuates reserpine-induced depression in mice partially by regulating 5-HTT, BDNF and TPH1 in the hippocampus and PFC of mice.

The system-neurophysiological basis for how methylphenidate modulates perceptual-attentional conflicts during auditory processing.

The ability to selectively perceive and flexibly attend to relevant sensory signals in the environment is essential for action control. Whereas neuromodulation of sensory or attentional processing is often investigated, neuromodulation of interactive effects between perception and attention, that is, high attentional control demand when the relevant sensory information is perceptually less salient than the irrelevant one, is not well understood. To fill this gap, this pharmacological-electroencephalogram (EEG) study applied an intensity-modulated, focused-attention dichotic listening paradigm together with temporal EEG signal decomposition and source localization analyses. We used a double-blind MPH/placebo crossover design to delineate the effects of methylphenidate (MPH)-a dopamine/norepinephrine transporter blocker-on the resolution of perceptual-attentional conflicts, when perceptual saliency and attentional focus favor opposing ears, in healthy young adults. We show that MPH increased behavioral performance specifically in the condition with the most pronounced conflict between perceptual saliency and attentional focus. On the neurophysiological level, MPH effects in line with the behavioral data were observed after accounting for intraindividual variability in the signal. More specifically, MPH did not show an effect on stimulus-related processes but modulated the onset latency of processes between stimulus evaluation and responding. These modulations were further shown to be associated with activation differences in the temporoparietal junction (BA40) and the superior parietal cortex (BA7) and may reflect neuronal gain modulation principles. The findings provide mechanistic insights into the role of modulated dopamine/norepinephrine transmitter systems for the interactions between perception and attention.

The triple monoamine re-uptake inhibitor DOV 216,303 promotes functional recovery after spinal cord contusion injury in mice.

Serotonin, noradrenaline and dopamine are important neuromodulators for locomotion in the spinal cord. Disruption of descending axons after spinal cord injury resulted in reduction of excitatory and neuromodulatory inputs to spinal neurons for locomotion. Receptor agonists or reuptake inhibitors for these neuromodulators have been shown to be beneficial in incomplete spinal cord injury. In this study, we tested a triple re-uptake inhibitor, DOV 216,303, for its ability to affect motor function recovery after spinal cord injury in mice. We impacted C57 mouse spinal cord at the T11 vertebral level and administered vehicle or DOV 216,303 at 10 mg/kg, b.i.d via intraperitoneal injections for 7 days. We monitored motor function with the Basso Mouse Scale for locomotion for 4 weeks. Spinal cords were harvested and histological examinations were performed to assess tissue sparing and lesion severity. Results showed that DOV 216,303-treated mice recovered significantly better than vehicle treated mice starting at 14 days post injury until the end of the survival period. Lesion size of the DOV 216,303 treated mice was also smaller compared to that of vehicle treated mice. This study suggests DOV 216,303 as a potential therapeutic after spinal cord injury warrants further investigation.

Desvenlafaxine 50 and 100 mg/d versus placebo for the treatment of major depressive disorder: a phase 4, randomized controlled trial.

OBJECTIVE: To assess short-term efficacy and safety of desvenlafaxine 50 and 100 mg/d versus placebo for treating major depressive disorder (MDD). Assessment of sexual function was a secondary objective. METHOD: Outpatients (≥ 18 years) who met criteria for MDD from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision and had screening and baseline 17-item Hamilton Depression Rating Scale (HDRS17) total scores ≥ 20 were randomly assigned to placebo or desvenlafaxine 50 or 100 mg/d in an 8-week study conducted from October 2011 to August 2012. The primary efficacy end point was change from baseline in HDRS17 total score at week 8, analyzed using a mixed-effects model for repeated measures. Sexual function was assessed using the Arizona Sexual Experiences Scale (ASEX). RESULTS: The safety population included 909 patients (intent-to-treat population, n = 886). Significantly greater improvement in adjusted mean HDRS17 total score from baseline to week 8 was observed for desvenlafaxine 50 mg (-11.28; P = .006) and desvenlafaxine 100 mg (-11.67; P < .001) compared with placebo (-9.71), with adjustment for multiplicity. In the ASEX total score analysis (n = 422), the treatment by gender interaction was not significant; thus, genders were combined for subsequent analyses. Comparisons for desvenlafaxine versus placebo for change from baseline in ASEX total and all item scores found P > .05, with no adjustment for multiplicity. Rates of sexual dysfunction based on ASEX were comparable among treatment groups. CONCLUSIONS: These results support previous findings demonstrating antidepressant efficacy, safety, and tolerability of desvenlafaxine 50 and 100 mg/d versus placebo. Sexual function was comparable between desvenlafaxine and placebo. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01432457.

Safety, pharmacokinetic, and positron emission tomography evaluation of serotonin and dopamine transporter occupancy following multiple-dose administration of the triple monoamine reuptake inhibitor BMS-820836.

RATIONALE: BMS-820836 is a novel antidepressant that selectively inhibits the reuptake of serotonin, norepinephrine, and dopamine. OBJECTIVE: This Phase I study assessed safety, tolerability, and pharmacokinetics of multiple daily doses of BMS-820836 in healthy subjects. Central serotonin transporter (SERT) and dopamine transporter (DAT) occupancy were assessed using positron emission tomography and [(11)C]MADAM or [(11)C]PE2I, respectively. METHODS: Fifty-seven healthy volunteers were enrolled in this double-blind, placebo-controlled, ascending multiple-dose study (ClincalTrials.gov identifier: NCT00892840). Eight participants in seven dose cohorts received oral doses of BMS-820836 (0.1-4 mg) or placebo for 14 days to assess safety, tolerability, and pharmacokinetics. Additionally, SERT and DAT occupancies were evaluated in 4-8 subjects per cohort at 8 h post-dose on Day 10 and 24 h post-dose on Day 15 at anticipated steady-state conditions. RESULTS: Most adverse events were mild to moderate; there were no serious safety concerns. Median maximum concentrations of BMS-820836 were observed at 4.0-5.5 h post-dose; estimated elimination half-life was 44-74 h. About 80 % striatal SERT occupancy was achieved after multiple doses of 0.5 mg BMS-820836 at both 8 and 24 h post-dose. Striatal DAT occupancy ranged between 14 % and 35 % at 8 h post-dose with a slight decline at 24 h post-dose. CONCLUSIONS: Multiple daily doses of up to 4 mg BMS-820836 appeared to be generally safe and well tolerated in a healthy population. SERT and DAT occupancies were in a range associated with therapeutic efficacy of antidepressants. Together with the pharmacokinetic profile of BMS-820836, the occupancy data support once-daily administration.

Antinociceptive activity of the new triple reuptake inhibitor NS18283 in a mouse model of chemotherapy-induced neuropathic pain.

BACKGROUND: Chronic neuropathic pain can lead to anxiety and depression. Drugs that block reuptake of serotonin, norepinephrine and/or dopamine are widely used to treat depression, and have emerged as useful drugs in the treatment of neuropathic pain. This study compared the acute antinociceptive effects of NS18283, a novel triple monoamine reuptake inhibitor (MRI) with indatraline, venlafaxine and escitalopram in a mouse model of neuropathic pain. METHOD: Neuropathic pain-like behaviours were induced in mice by repeated injections of oxaliplatin (OXA), and assessed using the von Frey hair test, the cold plate test and the thermal preference plate test. Anxio/depressive phenotype and antidepressant-like properties of compounds were assessed by the novelty suppressed feeding test and the tail suspension test, respectively. RESULTS: In vivo microdialysis experiments showed that each MRI increased extracellular serotonin, norepinephrine and/or dopamine levels in the cingulate cortex, in agreement with their in vitro reuptake inhibitory properties. Indatraline (3 mg/kg) reversed the full repertoire of OXA-induced neuropathic hypersensitivity. NS18283 (10 mg/kg) reversed OXA-induced mechano-hypersensitivity and cold allodynia. Venlafaxine (16 mg/kg) and escitalopram (4 mg/kg) only reversed cold allodynia and mechano-hypersensitivity, respectively. All MRIs produced antidepressant-like activity in anxio/depressive phenotype of OXA mice. CONCLUSIONS: Acute administration of drugs that enhance the activity of serotonin, norepinephrine and dopamine neurotransmission within nociceptive pathways may provide a broader spectrum of antinociception than dual or selective reuptake inhibitors in animal models of neuropathic pain. Whether similar observations would occur after repeated administration of such compounds in an attempt to simulate dosing in humans, or be compromised by dopaminergic-mediated adverse effects warrants further investigation.

Glial dysfunction in the mouse habenula causes depressive-like behaviors and sleep disturbance.

The lateral habenula (LHb) regulates the activity of monoaminergic neurons in the brainstem. This area has recently attracted a surge of interest in psychiatry because studies have reported the pathological activation of the habenula in patients with major depression and in animal models. The LHb plays a significant role in the pathophysiology of depression; however, how habenular neurons are activated to cause various depression symptoms, such as reduced motivation and sleep disturbance, remain unclear. We hypothesized that dysfunctional astrocytes may cause LHb hyperactivity due to the defective uptake activity of extracellular glutamate, which induces depressive-like behaviors. We examined the activity of neurons in habenular pathways and performed behavioral and sleep analyses in mice with pharmacological and genetic inhibition of the activity of the glial glutamate transporter GLT-1 in the LHb. The habenula-specific inhibition of GLT-1 increased the neuronal firing rate and the level of c-Fos expression in the LHb. Mice with reduced GLT-1 activity in the habenula exhibited a depressive-like phenotype in the tail suspension and novelty-suppressed feeding tests. These animals also displayed increased susceptibility to chronic stress, displaying more frequent avoidant behavior without affecting locomotor activity in the open-field test. Intriguingly, the mice showed disinhibition of rapid eye movement sleep, which is a characteristic sleep pattern in patients with depression. These results provide evidence that disrupting glutamate clearance in habenular astrocytes increases neuronal excitability and depressive-like phenotypes in behaviors and sleep.

Allowing for non-adherence to treatment in a randomized controlled trial of two antidepressants (citalopram versus reboxetine): an example from the GENPOD trial.

BACKGROUND: Meta-analyses suggest that reboxetine may be less effective than other antidepressants. Such comparisons may be biased by lower adherence to reboxetine and subsequent handling of missing outcome data. This study illustrates how to adjust for differential non-adherence and hence derive an unbiased estimate of the efficacy of reboxetine compared with citalopram in primary care patients with depression. METHOD: A structural mean modelling (SMM) approach was used to generate adherence-adjusted estimates of the efficacy of reboxetine compared with citalopram using GENetic and clinical Predictors Of treatment response in Depression (GENPOD) trial data. Intention-to-treat (ITT) analyses were performed to compare estimates of effectiveness with results from previous meta-analyses. RESULTS: At 6 weeks, 92% of those randomized to citalopram were still taking their medication, compared with 72% of those randomized to reboxetine. In ITT analysis, there was only weak evidence that those on reboxetine had a slightly worse outcome than those on citalopram [adjusted difference in mean Beck Depression Inventory (BDI) scores: 1.19, 95% confidence interval (CI) -0.52 to 2.90, p = 0.17]. There was no evidence of a difference in efficacy when differential non-adherence was accounted for using the SMM approach for mean BDI (-0.29, 95% CI -3.04 to 2.46, p = 0.84) or the other mental health outcomes. CONCLUSIONS: There was no evidence of a difference in the efficacy of reboxetine and citalopram when these drugs are taken and tolerated by depressed patients. The SMM approach can be implemented in standard statistical software to adjust for differential non-adherence and generate unbiased estimates of treatment efficacy for comparisons of two (or more) active interventions.

Extended-release quetiapine fumarate (quetiapine XR) as adjunctive therapy in patients with generalized anxiety disorder and a history of inadequate treatment response: a randomized, double-blind study.

BACKGROUND: For many patients with generalized anxiety disorder (GAD), first-line treatment does not lead to remission. This study investigated the efficacy and tolerability of adjunctive extended-release quetiapine fumarate (quetiapine XR) in patients with GAD and an inadequate response to selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). METHODS: Patients were randomized to quetiapine XR or placebo adjunctive to SSRI/SNRIs in an 11-week study. The primary endpoint was change from randomization to week 8 in Hamilton Anxiety Rating Scale (HAM-A) total score. Secondary variables were HAM-A psychic/somatic clusters, response, and remission, and Clinical Global Impression­Severity of Illness (CGI-S) score. RESULTS: A total of 409 patients received quetiapine XR (n=209) or placebo (n=200). The week 8 mean change in HAM-A total score was not statistically significant for quetiapine XR (­10.74; P=.079) vs placebo (­9.61). Secondary variables were generally consistent with the primary analysis, except for a significant reduction in HAM-A total score (week 1) and significant improvements in HAM-A psychic cluster and CGI-S total scores (week 8). Adverse events included dry mouth, somnolence, sedation, headache, and dizziness. CONCLUSIONS: In patients with GAD and an inadequate response to SSRI/SNRIs, adjunctive quetiapine XR did not show a statistically significant effect for the primary endpoint at week 8, although some secondary endpoints were statistically significant vs placebo. Quetiapine XR was generally well tolerated.

Evaluation of safety and tolerability, pharmacokinetics, and pharmacodynamics of BMS-820836 in healthy subjects: a placebo-controlled, ascending single-dose study.

RATIONALE: BMS-820836, a novel triple monoamine reuptake inhibitor, is an experimental monotherapy for sufferers of major depressive disorder who have had an inadequate response to an existing antidepressant treatment. OBJECTIVES: This study was conducted to evaluate the safety and tolerability, pharmacokinetics (PK), and serotonin transporter (SERT) and dopamine transporter (DAT) occupancy for single doses of BMS-820836 in healthy subjects. METHODS: Healthy subjects were assigned to seven BMS-820836 dose panels (0.025, 0.1, 0.5, 1, 2, 3, and 5 mg; n = 8 each), in which subjects were randomly allocated 3:1 to a single BMS-820836 dose or matched placebo. Serial blood samples were collected on Days 1, 2, 3, 4, 7, and 14 to characterize the PK of BMS-820836. Following evaluation of the maximum tolerated dose, SERT occupancy was determined by applying [(11)C]DASB positron emission tomography (PET) after single-dose BMS-820836 (0.5 or 3 mg; n = 3 each) and DAT occupancy by applying [(11)C]PE2I PET after single-dose BMS-820836 (3 mg; n = 6). RESULTS: Single oral doses of BMS-820836 (0.025-3 mg) were generally safe and well tolerated. BMS-820836 had a median T max of 5.0-7.2 h and a mean apparent terminal T 1/2 of 34-57 h. Mean striatal SERT occupancies were 19 ± 9 % and 82 ± 8 % after single doses of 0.5 and 3 mg BMS-820836, respectively. The mean striatal DAT occupancy was 19 ± 9 % after a single 3 mg BMS-820836 dose. CONCLUSIONS: Single doses of BMS-820836 have meaningful SERT and DAT occupancy and demonstrate an acceptable safety and tolerability profile in healthy control subjects.

Drug-specific laterality effects on frontal lobe activation of atomoxetine and methylphenidate in attention deficit hyperactivity disorder boys during working memory.

BACKGROUND: The catecholamine reuptake inhibitors methylphenidate (MPH) and atomoxetine (ATX) are the most common treatments for attention deficit hyperactivity disorder (ADHD). This study compares the neurofunctional modulation and normalization effects of acute doses of MPH and ATX within medication-naive ADHD boys during working memory (WM). METHOD: A total of 20 medication-naive ADHD boys underwent functional magnetic resonance imaging during a parametric WM n-back task three times, under a single clinical dose of either MPH, ATX or placebo in a randomized, double-blind, placebo-controlled, cross-over design. To test for normalization effects, brain activations in ADHD under each drug condition were compared with that of 20 age-matched healthy control boys. RESULTS: Relative to healthy boys, ADHD boys under placebo showed impaired performance only under high WM load together with significant underactivation in the bilateral dorsolateral prefrontal cortex (DLPFC). Both drugs normalized the performance deficits relative to controls. ATX significantly enhanced right DLPFC activation relative to MPH within patients, and significantly normalized its underactivation relative to controls. MPH, by contrast, both relative to placebo and ATX, as well as relative to controls, upregulated the left inferior frontal cortex (IFC), but only during 2-back. Both drugs enhanced fronto-temporo-striatal activation in ADHD relative to control boys and deactivated the default-mode network, which were negatively associated with the reduced DLPFC activation and performance deficits, suggesting compensation effects. CONCLUSIONS: The study shows both shared and drug-specific effects. ATX upregulated and normalized right DLPFC underactivation, while MPH upregulated left IFC activation, suggesting drug-specific laterality effects on prefrontal regions mediating WM.

Extended-release quetiapine fumarate (quetiapine XR) as adjunctive therapy in patients with generalized anxiety disorder and a history of inadequate treatment response: a randomized, double-blind study.

BACKGROUND: For many patients with generalized anxiety disorder (GAD), first-line treatment does not lead to remission. This study investigated the efficacy and tolerability of adjunctive extended-release quetiapine fumarate (quetiapine XR) in patients with GAD and an inadequate response to selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). METHODS: Patients were randomized to quetiapine XR or placebo adjunctive to SSRI/SNRIs in an 11-week study. The primary endpoint was change from randomization to week 8 in Hamilton Anxiety Rating Scale (HAM-A) total score. Secondary variables were HAM-A psychic/somatic clusters, response, and remission, and Clinical Global Impression­Severity of Illness (CGI-S) score. RESULTS: A total of 409 patients received quetiapine XR (n = 209) or placebo (n = 200). The week 8 mean change in HAM-A total score was not statistically significant for quetiapine XR (­10.74; P = .079) vs placebo (­9.61). Secondary variables were generally consistent with the primary analysis, except for a significant reduction in HAM-A total score (week 1) and significant improvements in HAM-A psychic cluster and CGI-S total scores (week 8). Adverse events included dry mouth, somnolence, sedation, headache, and dizziness. CONCLUSIONS: In patients with GAD and an inadequate response to SSRI/ SNRIs, adjunctive quetiapine XR did not show a statistically significant effect for the primary endpoint at week 8, although some secondary endpoints were statistically significant vs placebo. Quetiapine XR was generally well tolerated.

A 10-month, open-label evaluation of desvenlafaxine in Japanese outpatients with major depressive disorder.

The objective of this study was to evaluate the long-term safety of desvenlafaxine for continuation treatment of major depressive disorder (MDD) in Japanese patients. This was a phase 3, multicenter, 10-month, open-label study with flexible dosing of desvenlafaxine (25, 50, 100 mg/day). Japanese patients with MDD who had completed an 8-week, double-blind, placebo-controlled study in which patients received 25 or 50 mg/day desvenlafaxine or placebo were enrolled. In this study, patients received desvenlafaxine 25 mg/day from days 1 to 14, with subsequent upward titration, to a maximum of 100 mg/day, determined by clinical response. Of 304 patients, 75 (24.7%) discontinued during the on-therapy period; patient request was the most common reason (11.5%). Treatment-emergent adverse events were reported by 240 patients (78.9%) during the on-therapy period; the most common adverse events were nasopharyngitis (37.2%), somnolence (11.5%), headache (10.5%), and nausea (10.2%). For the ITT-LOCF population, the mean change from baseline in the 17-item Hamilton Rating Scale for Depression (HAM-D17) total score was -4.76 (95% confidence interval: -5.47 to -4.05); continued numerical improvements in the HAM-D17 total scores and other depression outcome measures were observed irrespective of treatment in the previous study. Long-term use of desvenlafaxine was safe and well tolerated, with a clinical benefit/risk profile similar to that in other populations.

An open-label, single-dose, parallel-group study of the effects of chronic hepatic impairment on the safety and pharmacokinetics of desvenlafaxine.

BACKGROUND: Many antidepressants are extensively metabolized in the liver, requiring dose adjustments in individuals with hepatic impairment. Clinical studies indicate that the serotonin-norepinephrine reuptake inhibitor desvenlafaxine is metabolized primarily via glucuronidation, and ∼45% is eliminated unchanged in urine. OBJECTIVE: The objectives of this study were to assess the pharmacokinetic profile, safety, and tolerability of desvenlafaxine in adults with chronic Child-Pugh class A, B, and C hepatic impairment. METHODS: Subjects (aged 18-65 years) with mild (Child-Pugh class A, n = 8), moderate (Child-Pugh class B, n = 8), and severe (Child-Pugh class C, n = 8) hepatic impairment and 12 healthy matched subjects received a single 100-mg oral dose of desvenlafaxine. Disposition of (R)-, (S)-, and (R+S)-enantiomers of desvenlafaxine were examined in plasma and urine. Geometric least squares (GLS) mean ratios and 90% CIs for AUC, AUC0-τ, Cmax, and Cl/F were calculated; comparisons were made by using a 1-factor ANOVA. Safety was evaluated according to adverse events, physical examination, vital signs, and laboratory assessments. RESULTS: Healthy participants had a mean age of 51 years (range, 36-62 years) and weight of 79.1 kg (range, 52.5-105.0 kg); hepatically impaired participants had a mean age of 52 years (range, 31-65 years) and weight of 80.9 kg (range, 50.2-119.5 kg). In both groups, 67% of participants were male. No statistically significant differences (≥50%) in the disposition of desvenlafaxine were detected between hepatically impaired patients and healthy subjects based on GLS mean ratios for Cmax, AUC0-τ, AUC, or Cl/F (P > 0.05 for each comparison). Median Tmax was similar for all groups (range, 6-9 hours). A nonsignificant increase was observed for desvenlafaxine exposure in patients with moderate or severe hepatic impairment (GLS mean ratios [90% CIs] for AUC, 31% [93.2-184], 35% [96.5-190], respectively). The most common adverse events were nausea (n = 2, healthy subjects; n = 3, hepatically impaired subjects) and vomiting (n = 1, healthy subjects; n = 2, hepatically impaired subjects). CONCLUSIONS: A single 100-mg dose of desvenlafaxine was well tolerated in healthy subjects and hepatically impaired patients. A mild increase in exposure was observed for moderate and severe hepatically impaired subjects (Child-Pugh class B and C).

Supraspinal and spinal effects of L-trans-PDC, an inhibitor of glutamate transporter, on the micturition reflex in rats.

AIMS: Glutamate is a major excitatory transmitter in the central nervous system, controlling lower urinary tract function. Five types of glutamate transporters such as GLAST (EAAT1), GLT-1 (EAAT2), EAAC-1 (EAAT3), EAAT4, and EAAT5 have been cloned so far. In the current study we tested whether L-trans-pyrrolidine-2,4-dicarboxylic acid (L-trans-PDC), a non-selective inhibitor of glutamate transporters that increases endogenous glutamate concentration, can affect the micturition reflex in urethane anesthetized rats. METHODS: Continuous cystometrograms (CMG, 0.04 ml/min infusion rate) were performed in two groups of urethane-anesthetized rats. A group of 18 rats was used for intrathecal administration of 1-10 µg of L-trans-PDC via an intrathecal catheter. In the second group of 18 rats, 1-10 µg of L-trans-PDC were administered intracerebroventricularly via a catheter inserted into the lateral ventricle. Micturition parameters were recorded and compared before and after drug administration. RESULTS: Intrathecal administration of L-trans-PDC at 1, 3, and 10 µg (n = 6 per dose) increased intercontraction intervals in dose dependent fashion, but did not affect postvoid residual or basal pressure at any doses tested. Intracerebroventricular administration of L-trans-PDC at 1, 3, and 10 µg (n = 6 per dose) also increased intercontraction intervals in dose dependent fashion, but did not affect postvoid residual or basal pressure at any doses tested. CONCLUSIONS: The current results show that, in urethane-anesthetized rats, suppression of glutamate transporters by L-trans-PDC has an inhibitory effect on the micturition reflex at supraspinal and spinal sites, possibly via activation of glutamate-mediated inhibitory pathways.