Comparative affinity of duloxetine and venlafaxine for serotonin and norepinephrine transporters in vitro and in vivo, human serotonin receptor subtypes, and other neuronal receptors

Understanding the differential impacts of two antidepressants on locomotion of freshwater snails (Lymnaea stagnalis)

There is growing evidence of negative impacts of antidepressants on behavior of aquatic non-target organisms. Accurate environmental risk assessment requires an understanding of whether antidepressants with similar modes of action have consistent negative impacts. Here, we tested the effect of acute exposure to two antidepressants, fluoxetine and venlafaxine (0-50 µg/L), on the behavior of non-target organism, i.e., freshwater pond snail, Lymnaea stagnalis. As compounds interact with chemical cues in the aquatic ecosystems, we also tested whether the effects altered in the presence of bile extract containing 5α-cyprinol sulfate (5α-CPS), a characterized kairomone of a natural predator, common carp (Cyprinus carpio). Behavior was studied using automated tracking and analysis of various locomotion parameters of L. stagnalis. Our results suggest that there are differences in the effects on locomotion upon exposure to venlafaxine and fluoxetine. We found strong evidence for a non-monotonic dose response on venlafaxine exposure, whereas fluoxetine only showed weak evidence of altered locomotion for a specific concentration. Combined exposure to compounds and 5α-CPS reduced the intensity of effects observed in the absence of 5α-CPS, possibly due to reduced bioavailability of the compounds. The results highlight the need for acknowledging different mechanisms of action among antidepressants while investigating their environmental risks. In addition, our results underline the importance of reporting non-significant effects and acknowledging individual variation in behavior for environmental risk assessment.

Daily intake of 30 mg duloxetine is effective in decreasing premature ejaculation severity: a prospective randomized placebo-controlled cross over clinical trial

BACKGROUND

Premature ejaculation (PE) is considered to be the most common male sexual disorder affecting 20% to 66% of sexually active men. Most of the patients had already tried on demand dapoxitine with no improvement. We aimed in the current study to assert the efficacy and safety profile of daily intake of 30 mg duloxetine in treating patients with lifelong premature ejaculation (LPE) as well as patients with acquired premature ejaculation (APE).

RESULTS

The current study showed significant improvement in intravaginal ejaculatory latency time (IELT) after intake of duloxetine. All participants had a median Arabic index of premature ejaculation (AIPE) of 26, median IELT of 180 s, median male sexual quality of life (SQOL) of 43 after being treated with duloxetine (p value < 0.001 for all). While median AIPE after placebo was 19, median IELT after placebo was 60 s and median male SQOL after placebo was 21. Paired comparison of AIPE, IELT (Secs), inter quartile range (IQR) and male SQOL in group (A) patients at baseline and after duloxetine intake showed statistically significant improvement among treated patients (p values < 0.001 for all). Paired comparison of AIPE, IELT (Secs), IQR and male SQOL in group (A) patients at baseline and after placebo treatment showed no significant improvement of male SQOL. Furthermore, AIPE and IELT returned to baseline scores after discontinuation of duloxetine (p values 0.729; 0.892, respectively). Paired comparison of AIPE, IELT (Secs), IQR and male SQOL in group (B) patients at baseline and after placebo treatment showed almost same scores of patients in group (A) who received placebo for 2 months after a 2 month washout period (p values 1.000 for all). Paired comparison of AIPE, IELT (Secs), IQR and male SQOL in group (B) patients at baseline and after duloxetine treatment showed statistically significant improvement among all treated patients (p values < 0.001 for all).

CONCLUSION

Duloxetine is an effective drug for treatment of LPE and APE patients. Further, larger studies are needed to compare duloxetine to different known therapeutic modalities for PE to assert it's efficacy and superiority.

Algorithm for multimodal medication therapy in patients with complex regional pain syndrome

Complex regional pain syndrome (CRPS), previously known as reflex sympathetic dystrophy and causalgia, is a clinical entity characterized by classic neuropathic pain, autonomic involvement, motor symptoms, and trophic changes in the skin, nails, and hair. Although various therapeutic modalities are used to control CRPS-related pain, severe pain due to CRPS often persists and progresses to the chronic phase. In this study, we constructed an algorithm for multimodal medication therapy for CRPS based on the established pathology of CRPS. Oral steroid pulse therapy is recommended for initial pain management in patients with CRPS. Oral steroid therapy can reduce peripheral and central neuroinflammation, contributing to the development of neuropathic pain during the acute and chronic phases. If steroid pulse therapy offers poor relief or is ineffective, treatment to control central sensitization in the chronic phase should be initiated. If pain persists despite all drug adjustments, ketamine with midazolam 2 mg before and after ketamine injection can be administered intravenously to inhibit the N-methyl D-aspartate receptor. If this treatment fails to achieve sufficient efficacy, intravenous lidocaine can be administered for 2 weeks. We hope that our proposed drug treatment algorithm to control CRPS pain will help clinicians appropriately treat patients with CRPS. Further clinical studies assessing patients with CRPS are warranted to establish this treatment algorithm in clinical practice.

Utility of pharmacogenetic testing to optimise antidepressant pharmacotherapy in youth: a narrative literature review

Pharmacogenetics (PGx) is the study and application of how interindividual differences in our genomes can influence drug responses. By evaluating individuals' genetic variability in genes related to drug metabolism, PGx testing has the capabilities to individualise primary care and build a safer drug prescription model than the current "one-size-fits-all" approach. In particular, the use of PGx testing in psychiatry has shown promising evidence in improving drug efficacy as well as reducing toxicity and adverse drug reactions. Despite randomised controlled trials demonstrating an evidence base for its use, there are still numerous barriers impeding its implementation. This review paper will discuss the management of mental health conditions with PGx-guided treatment with a strong focus on youth mental illness. PGx testing in clinical practice, the concerns for its implementation in youth psychiatry, and some of the barriers inhibiting its integration in clinical healthcare will also be discussed. Overall, this paper provides a comprehensive review of the current state of knowledge and application for PGx in psychiatry and summarises the capabilities of genetic information to personalising medicine for the treatment of mental ill-health in youth.

Moving from serotonin to serotonin-norepinephrine enhancement with increasing venlafaxine dose: clinical implications and strategies for a successful outcome in major depressive disorder

INTRODUCTION

Mental health disorders, especially depressive and anxiety disorders, are associated with substantial health-related burden. While the second-generation antidepressants are widely accepted as first-line pharmacological treatment for major depressive disorder (MDD), patient response to such treatment is variable, with more than half failing to achieve complete remission, and residual symptoms are frequently present.

AREAS COVERED

Here, the pharmacodynamics of venlafaxine XR are reviewed in relation to its role as both a selective serotonin reuptake inhibitor (SSRI) and a serotonin-norepinephrine-reuptake inhibitor (SNRI), and we look at how these pharmacodynamic properties can be harnessed to guide clinical practice, asking the question 'is it possible to develop a symptom-cluster-based approach to the treatment of MDD with comorbid anxiety utilizing venlafaxine XR?.' Additionally, three illustrative clinical cases provide practical examples of the utility of venlafaxine-XR in real-world clinical practice. The place of venlafaxine XR in managing fatigue/low energy, a frequent residual symptom in MDD, is explored using pooled data from clinical trials of venlafaxine XR.

EXPERT OPINION

Venlafaxine XR should be considered as a first-line treatment for MDD with or without comorbid anxiety, and there are clear pharmacodynamic signals supporting a symptom cluster-based treatment paradigm for venlafaxine XR.

A randomized, double-blinded, placebo-controlled clinical trial of duloxetine hydrochloride enteric-coated tablets in the treatment of refractory chronic cough

INTRODUCTION

Refractory cough, a chronic cough with an unclear diagnosis or poor treatment response. The symptoms are often stubborn and persistent, causing serious complications and lowering the patient's quality of life. Cough hypersensitivity syndrome (CHS) is proposed as a potential cause, and reducing sensory nerve hyperresponsiveness is suggested as an effective treatment. However, current drugs have low efficacy and benefit rates and numerous side effects. This trail proposes using duloxetine, a selective 5-HT and norepinephrine reuptake inhibitor, as a potential treatment for refractory cough, which has shown promise in treating pain and depression. Duloxetine may inhibit pain conduction and oxidative stress in peripheral nerves by inhibiting the activity of TRPV1 channels, which play an important role in the peripheral afferent pathway of refractory cough. Meanwhile, the antidepressant effects of duloxetine may also play a role in the treatment of refractory cough.

METHODS AND ANALYSIS

This is a single-center, prospective, randomized, double-blind, and controlled trial. A total of 98 individuals will be randomized in a 1:1 ratio to duloxetine group and placebo control group (starting with 20 mg QD, increasing 20 mg daily until 20 mg TID). After a screening period, the second stage runs from baseline to the 42nd (last) day of treatment, with follow-up visits on the 3rd, 7th, 14th, 21st, 28th, 35th, 42nd and 49th days. The main end-stage observation indicators include objective cough frequency, cough visual analog scale (VAS), cough symptom score, Leicester Cough Questionnaire (LCQ), and cough evaluation test (CET); the secondary end-stage observation indicators include capsaicin cough sensitivity, Patient Health Questionnaire-9 (PHQ-9), Major Depression Inventory (MDI), the Generalized Anxiety Disorder-7 scale (GAD-7), Life Events Scale (LES-32), induced sputum supernatant. The safety measures will be AEs/SAEs, vital signs, liver and kidney function, fecal occult blood test.

DISCUSSION

This study is the first randomized, double-blind, and controlled clinical trial investigating the use of duloxetine in the treatment of refractory coughs. The study aims to provide a high-quality basis for evaluating the efficacy and safety of duloxetine for this condition.

TRIAL REGISTRATION

Our study was registered in the Chinese Clinical Trials Register ( www.chictr.org.cn/ ) (ChiCTR2000037429) in 28/08/2020.

[Understanding and assessing the antidepressant drug-associated risk of bleeding]

Antidepressants, in particular selective serotonin reuptake inhibitors (SSRIs), are the most commonly prescribed psychopharmacological drug group. Thus, a precise knowledge of the expected adverse drug reactions is indispensable. The increased risk of bleeding events is well documented, especially in patients treated with SSRIs. However, many other antidepressant drug groups have also been implicated in increasing the risk of bleeding. In the following review, the thrombocytic serotonin system and the respective targets of the different antidepressants are explained. Subsequently, the available literature on bleeding under the respective antidepressant classes or individual substances is presented, using data from meta-analyses whenever possible. In addition to the risk of bleeding in general, individual bleeding entities are also considered, such as gastrointestinal and cerebral hemorrhages. Finally, the effects of other drugs that increase the risk of bleeding (i. e., nonsteroidal anti-inflammatory drugs, platelet aggregation inhibitors and anticoagulants) in combination with antidepressant drugs are discussed. The information presented here is meant to guide practitioner's decision making regarding an appropriate antidepressant pharmacotherapy based on the patient's individual risk constellation.

A multicenter, randomized, double-blind, duloxetine-controlled, non-inferiority trial of desvenlafaxine succinate extended-release in patients with major depressive disorder

BACKGROUND

Desvenlafaxine and duloxetine are selective serotonin and norepinephrine reuptake inhibitors. Their efficacy has not been directly compared using statistical hypotheses. This study evaluated the non-inferiority of desvenlafaxine extended-release (XL) to duloxetine in patients with major depressive disorder (MDD).

METHODS

In this study, 420 adult patients with moderate-to-severe MDD were enrolled and randomly assigned (1:1) to receive 50 mg (once daily [QD]) of desvenlafaxine XL (n = 212) or 60 mg QD of duloxetine (n = 208). The primary endpoint was evaluated using a non-inferiority comparison based on the change from baseline to 8 weeks in the 17-item Hamilton Depression Rating Scale (HAMD₁₇) total score. Secondary endpoints and safety were evaluated.

RESULTS

Least-squares mean change in HAM-D₁₇ total score from baseline to 8 weeks was -15.3 (95% confidence interval [CI]: -17.73, -12.89) in the desvenlafaxine XL group and - 15.9 (95% CI, -18.44, -13.39) in the duloxetine group. The least-squares mean difference was 0.6 (95% CI: -0.48, 1.69), and the upper boundary of 95% CI was less than the non-inferiority margin (2.2). No significant between-treatment differences were found in most secondary efficacy endpoints. The incidence of the most common treatment-emergent adverse events (TEAEs) was lower for desvenlafaxine XL than for duloxetine for nausea (27.2% versus 48.8%) and dizziness (18.0% versus 28.8%).

LIMITATIONS

A short-term non-inferiority study without a placebo arm.

CONCLUSIONS

This study demonstrated that desvenlafaxine XL 50 mg QD was non-inferior to duloxetine 60 mg QD in efficacy in patients with MDD. Desvenlafaxine had a lower incidence of TEAEs than duloxetine did.

Carbamazepine, venlafaxine, tramadol, and their main metabolites: Toxicological effects on zebrafish embryos and larvae

Pharmaceutical compounds and their metabolites are found in natural and wastewater. However, investigation of their toxic effects on aquatic animals has been neglected, especially for metabolites. This work investigated the effects of the main metabolites of carbamazepine, venlafaxine and tramadol. Zebrafish embryos were exposed (0.1-100 µg/L) for 168hpf exposures to each metabolite (carbamazepine-10,11-epoxide, 10,11-dihydrocarbamazepine, O-desmethylvenlafaxine, N-desmethylvenlafaxine, O-desmethyltramadol, N-desmethyltramadol) or the parental compound. A concentration-response relationship was found for the effects of some embryonic malformations. Carbamazepine-10,11-epoxide, O-desmethylvenlafaxine and tramadol elicited the highest malformation rates. All compounds significantly decreased larvae responses on a sensorimotor assay compared to controls. Altered expression was found for most of the 32 tested genes. In particular, abcc1, abcc2, abcg2a, nrf2, pparg and raraa were found to be affected by all three drug groups. For each group, the modelled expression patterns showed differences in expression between parental compounds and metabolites. Potential biomarkers of exposure were identified for the venlafaxine and carbamazepine groups. These results are worrying, indicating that such contamination in aquatic systems may put natural populations at significant risk. Furthermore, metabolites represent a real risk that needs more scrutinising by the scientific community.

Duloxetine and Amitriptyline Reduce Neuropathic Pain by Inhibiting Primary Sensory Input to Spinal Dorsal Horn Neurons via α1- and α2-Adrenergic Receptors

Antidepressants, such as duloxetine and amitriptyline, are effective for treating patients with chronic neuropathic pain. Inhibiting norepinephrine and serotonin transporters at presynaptic terminals raises extracellular concentrations of norepinephrine. The α1- and α2-adrenergic receptor agonists inhibit glutamatergic input from primary afferent nerves to the spinal dorsal horn. However, the contribution of spinal α1- and α2-adrenergic receptors to the analgesic effect of antidepressants and associated synaptic plasticity remains uncertain. In this study, we showed that systemic administration of duloxetine or amitriptyline acutely reduced tactile allodynia and mechanical and thermal hyperalgesia caused by spinal nerve ligation in rats. In contrast, duloxetine or amitriptyline had no effect on nociception in sham rats. Blocking α1-adrenergic receptors with WB-4101 or α2-adrenergic receptors with yohimbine at the spinal level diminished the analgesic effect of systemically administered duloxetine and amitriptyline. Furthermore, intrathecal injection of duloxetine or amitriptyline similarly attenuated pain hypersensitivity in nerve-injured rats; the analgesic effect was abolished by intrathecal pretreatment with both WB-4101 and yohimbine. In addition, whole-cell patch-clamp recordings in spinal cord slices showed that duloxetine or amitriptyline rapidly inhibited dorsal root-evoked excitatory postsynaptic currents in dorsal horn neurons in nerve-injured rats but had no such effect in sham rats. The inhibitory effect of duloxetine and amitriptyline was abolished by the WB-4101 and yohimbine combination. Therefore, antidepressants attenuate neuropathic pain predominantly by inhibiting primary afferent input to the spinal cord via activating both α1- and α2-adrenergic receptors. This information helps the design of new strategies to improve the treatment of neuropathic pain.

Neuropathic pain: Mechanisms and therapeutic strategies

The physiopathology and neurotransmission of pain are of an owe inspiring complexity. Our ability to satisfactorily suppress neuropathic or other forms of chronic pain is limited. The number of pharmacodynamically distinct and clinically available medications is low and the successes achieved modest. Pain Medicine practitioners are confronted with the ethical dichotomy imposed by Hippocrates: On one hand the mandate of primum non nocere, on the other hand, the promise of heavenly joys if successful divinum est opus sedare dolorem. We briefly summarize the concepts associated with nociceptive pain from nociceptive input (afferents from periphery), modulatory output [descending noradrenergic (NE) and serotoninergic (5-HT) fibers] to local control. The local control is comprised of the "inflammatory soup" at the site of pain origin and synaptic relay stations, with an ATP-rich environment promoting inflammation and nociception while an adenosine-rich environment having the opposite effect. Subsequently, we address the transition from nociceptor pain to neuropathic pain (independent of nociceptor activation) and the process of sensitization and pain chronification (transient pain progressing into persistent pain). Having sketched a model of pain perception and processing we attempt to identify the sites and modes of action of clinically available drugs used in chronic pain treatment, focusing on adjuvant (co-analgesic) medication.

Emotional blunting with bupropion and serotonin reuptake inhibitors in three randomized controlled trials for acute major depressive disorder

BACKGROUND

Emotional blunting is theorized to be an adverse effect of antidepressants, particularly serotonin reuptake inhibitors, but this has not been firmly established. Another possibility is that emotional blunting represents a residual depressive symptom.

METHODS

We analyzed data from adult outpatients with acute major depressive disorder who participated in three 8-week randomized controlled trials. Trials 1 and 2 were pooled (venlafaxine, n = 378; bupropion, n = 389; placebo, n = 383) and Trial 3 (escitalopram, n = 254; bupropion, n = 260) was analyzed separately. Emotional blunting was measured with the "inability to feel" item from the Montgomery-Åsberg Depression Rating Scale.

RESULTS

Emotional responsiveness improved, on average, in all treatment groups. Only a minority of participants (≤6 %) experienced more emotional blunting post-treatment, compared to baseline, with no significant differences between treatment groups, although roughly 20-25 % continued to report an inability to feel normal emotions at the final assessment. In Trials 1 and 2, emotional blunting was associated with poorer outcomes in terms of depressive symptoms, suicidal ideation, and sexual function, but these correlations were nearly identical in the placebo group.

LIMITATIONS

The trials were short and cannot speak to the possibility of emotional blunting from long-term treatment. Emotional blunting was measured with a single item.

CONCLUSIONS

The study medications did not significantly decrease emotional responsiveness, and there was no evidence that emotional blunting mediated treatment response. In acute treatment, emotional blunting may be better conceptualized as a residual symptom than as an adverse drug effect.

The molecular pathophysiology of depression and the new therapeutics

Major depressive disorder (MDD) is a highly prevalent and disabling disorder. Despite the many hypotheses proposed to understand the molecular pathophysiology of depression, it is still unclear. Current treatments for depression are inadequate for many individuals, because of limited effectiveness, delayed efficacy (usually two weeks), and side effects. Consequently, novel drugs with increased speed of action and effectiveness are required. Ketamine has shown to have rapid, reliable, and long-lasting antidepressant effects in treatment-resistant MDD patients and represent a breakthrough therapy for patients with MDD; however, concerns regarding its efficacy, potential misuse, and side effects remain. In this review, we aimed to summarize molecular mechanisms and pharmacological treatments for depression. We focused on the fast antidepressant treatment and clarified the safety, tolerability, and efficacy of ketamine and its metabolites for the MDD treatment, along with a review of the potential pharmacological mechanisms, research challenges, and future clinical prospects.

Psychopharmacological properties and therapeutic profile of the antidepressant venlafaxine

Major depression (MD) is one of the most common psychiatric disorders worldwide. Currently, the first-line treatment for MD targets the serotonin system but these drugs, notably the selective serotonin reuptake inhibitors, usually need 4 to 6 weeks before the benefit is felt and a significant proportion of patients shows an unsatisfactory response. Numerous treatments have been developed to circumvent these issues as venlafaxine, a mixed serotonin-norepinephrine reuptake inhibitor that binds and blocks both the SERT and NET transporters. Despite this pharmacological profile, it is difficult to have a valuable insight into its ability to produce more robust efficacy than single-acting agents. In this review, we provide an in-depth characterization of the pharmacological properties of venlafaxine from in vitro data to preclinical and clinical efficacy in depressed patients and animal models of depression to propose an indirect comparison with the most common antidepressants. Preclinical studies show that the antidepressant effect of venlafaxine is often associated with an enhancement of serotonergic neurotransmission at low doses. High doses of venlafaxine, which elicit a concomitant increase in 5-HT and NE tone, is associated with changes in different forms of plasticity in discrete brain areas. In particular, the hippocampus appears to play a crucial role in venlafaxine-mediated antidepressant effects notably by regulating processes such as adult hippocampal neurogenesis or the excitatory/inhibitory balance. Overall, depending on the dose used, venlafaxine shows a high efficacy on depressive-like symptoms in relevant animal models but to the same extent as common antidepressants. However, these data are counterbalanced by a lower tolerance. In conclusion, venlafaxine appears to be one of the most effective treatments for treatment of major depression. Still, direct comparative studies are warranted to provide definitive conclusions about its superiority.

Outcomes and Predictors of Response of Duloxetine for the Treatment of Persistent Idiopathic Dentoalveolar Pain: A Retrospective Multicenter Observational Study

Background

Duloxetine has been reported to significantly relieve the pain of persistent idiopathic dentoalveolar pain (PIDP); however, the number of studies available is scarce and no study has identified the predictors of response of duloxetine for the treatment of PIDP.

Objective

To report the efficacy, safety, and identification of positive predictors of duloxetine for PIDP patients through a retrospective multicenter observational study.

Methods

We retrospectively reviewed the clinical database of PIDP patients who were prescribed duloxetine at 3 hospitals between January 2018 and November 2021. Demographic and pain-related baseline data, efficacy of patients after 3 months of medication by visual analog scale (VAS) scores for pain and adverse events were extracted and analyzed. The predictors of pain-relieving effect of duloxetine were identified by logistic regression analysis.

Results

A total of 135 patients were included in this study. Side effects occurred immediately after taking duloxetine in 24 (17.8%) patients, and the treatment with duloxetine was discontinued on 13 of them because they could not tolerate the side effects. Other 11 (8.1%) patients gradually tolerated the side effects within 2 weeks. Ninety-four out of 122 (77.0%) patients obtained pain relief with VAS significantly decreased (p < 0.01) and the other 28 (23.0%) patients stopped taking the drug because of weak efficacy. Binary logistic regression analysis showed that short disease duration (OR = 1.017, 95% CI = 1.004–1.030, P = 0.012) was an independent predictor of the positive response of duloxetine.

Conclusion

This study confirmed that duloxetine can significantly improve chronic pain of PIDP patients, and the safety was tolerable. Patients with shorter disease duration had more benefit from duloxetine.

Limitations

This is a retrospective observational study. Long-term efficacy and safety of duloxetine in the treatment of PIDP patients were not evaluated.

Concurrent anxiety in patients with major depression and cerebral serotonin 4 receptor binding. A NeuroPharm-1 study

Concurrent anxiety is frequent in major depressive disorder and a shared pathophysiological mechanism between anxiety and other depressive symptoms is plausible. The serotonin 4 receptor (5-HT₄R) has been implicated in both depression and anxiety. This is the first study to investigate the association between the cerebral 5-HT₄R binding and anxiety in patients with depression before and after antidepressant treatment and the association to treatment response. Ninety-one drug-free patients with depression were positron emission tomography scanned with the 5-HT₄R ligand [¹¹C]-SB207145. Depression severity and concurrent anxiety was measured at baseline and throughout 8 weeks of antidepressant treatment. Anxiety measures included four domains: anxiety/somatization factor score; Generalized Anxiety Disorder 10-items (GAD-10) score; anxiety/somatization factor score ≥7 (anxious depression) and syndromal anxious depression. Forty patients were rescanned at week 8. At baseline, we found a negative association between global 5-HT₄R binding and both GAD-10 score (p < 0.01) and anxiety/somatization factor score (p = 0.06). Further, remitters had a higher baseline anxiety/somatization factor score compared with non-responders (p = 0.04). At rescan, patients with syndromal anxious depression had a greater change in binding relative to patients with non-syndromal depression (p = 0.04). Concurrent anxiety in patients with depression measured by GAD-10 score and anxiety/somatization factor score is negatively associated with cerebral 5-HT₄R binding. A lower binding may represent a subtype with reduced natural resilience against anxiety in a depressed state, and concurrent anxiety may influence the effect on the 5-HT₄R from serotonergic antidepressants. The 5-HT₄R is a promising neuroreceptor for further understanding the underpinnings of concurrent anxiety in patients with depression.

Duloxetine overdose causes sympathomimetic and serotonin toxicity without major complications

OBJECTIVE

Duloxetine is a commonly used antidepressant that is a serotonin and norepinephrine reuptake inhibitor. We aimed to investigate the frequency and severity of clinical effects following duloxetine overdose.

METHODS

We undertook a retrospective review of duloxetine overdoses (>120 mg) admitted to two tertiary toxicology units between March 2007 and May 2021. Demographic information, details of ingestion (dose, co-ingestants), clinical effects, investigations (ECG parameters including QT interval), complications (coma [GCS < 9], serotonin toxicity, seizures and cardiovascular effects), length of stay [LOS] and intensive care unit [ICU] admission were extracted from a clinical database.

RESULTS

There were 241 duloxetine overdoses (>120 mg), median age 37 years (interquartile range [IQR]: 25-48 years) and there were 156 females (65%). The median dose was 735 mg (IQR: 405-1200 mg). In 177 patients, other medications were co-ingested, most commonly alcohol, paracetamol, quetiapine, diazepam, ibuprofen, pregabalin and oxycodone. These patients were more likely to be admitted to ICU (12 [7%] vs. none; p = 0.040), develop coma (16 [9%] vs. none; p = 0.008) and hypotension [systolic BP < 90 mmHg] (15 [8%] vs. one; p = 0.076). Sixty four patients ingested duloxetine alone with a median dose of 840 mg (180-4200 mg). The median LOS, in the duloxetine only group, was 13 h (IQR:8.3-18 h), which was significantly shorter than those taking coingestants, 19 h (IQR:12-31 h; p = 0.004). None of these patients were intubated. Six patients developed moderate serotonin toxicity, without complications and one had a single seizure. Tachycardia occurred in 31 patients (48%) and mild hypertension (systolic BP > 140 mmHg) in 29 (45%). One patient had persistent sympathomimetic toxicity, and one had hypotension after droperidol. Two patients of 63 with an ECG recorded had an abnormal QT: one QT 500 ms, HR 46 bpm, which resolved over 3.5 h and a second with tachycardia (QT 360 ms, HR 119 bpm). None of the 64 patients had an arrhythmia.

CONCLUSION

Duloxetine overdose most commonly caused sympathomimetic effects and serotonin toxicity, consistent with its pharmacology, and did not result in coma, arrhythmias or intensive care admission, when taken alone in overdose.

Glycerosomal thermosensitive in situ gel of duloxetine HCl as a novel nanoplatform for rectal delivery: in vitro optimization and in vivo appraisal

Duloxetine HCl (DXH) is a reuptake inhibitor of serotonin and norepinephrine used to treat the major depressive disorder. Following its extensive hepatic metabolism, acid-labile nature, and limited aqueous solubility, DXH has poor oral bioavailability (40%). The rectal route has been suggested as another route of administration to surmount such challenges. The present study aimed to prepare DXH-loaded glycerosomal (DXH-GLYS) in situ gel for rectal administration to increase DXH permeability and improve its bioavailability. Box-Behnken design (BBD) was adopted to prepare and optimize nanoglycerosomes. The impact of Phospholipon 90G (PL90G), Tween 80 concentrations, and glycerol percentage on encapsulation efficiency, nanoglycerosomal size, % cumulative DXH released, and the cumulative DXH permeated per unit area after 24 h were studied by the design. The pharmacokinetic and pharmacodynamic behavior of optimized formulation was investigated in rats. The formulated DXH-GLYS had a vesicle size ranging between 135.9 and 430.6 nm and an entrapment efficiency between 69.11 and 98.12%. The permeation experiment revealed that the optimized DXH-GLYS in situ gel increased DXH permeation by 2.62-fold compared to DXH solution. Pharmacokinetics studies disclosed that the DXH-GLYS in situ rectal gel exhibited 2.24-times increment in DXH bioavailability relative to oral DXH solution. The pharmacodynamic study revealed that the DXH-GLYS rectal treatment significantly improved the behavioral analysis parameters and was more efficacious as an antidepressant than the oral DXH solution. Collectively, these findings demonstrate that GLYS can be considered a potentially valuable rectal nanocarrier that could boost the DXH efficacy.

Polytyramine Film-Coated Single-Walled Carbon Nanotube Electrochemical Chemosensor with Molecularly Imprinted Polymer Nanoparticles for Duloxetine-Selective Determination in Human Plasma

We devised, fabricated, and tested differential pulse voltammetry (DPV) and impedance spectroscopy (EIS) chemosensors for duloxetine (DUL) antidepressant determination in human plasma. Polyacrylic nanoparticles were synthesized by precipitation polymerization and were molecularly imprinted with DUL (DUL-nanoMIPs). Then, together with the single-walled carbon nanotube (SWCNT) scaffolds, they were uniformly embedded in polytyramine films, i.e., nanoMIPs-SWCNT@(polytyramine film) surface constructs, deposited on gold electrodes by potentiodynamic electropolymerization. These constructs constituted recognition units of the chemosensors. The molecular dynamics (MD) designing of DUL-nanoMIPs helped select the most appropriate functional and cross-linking monomers and determine the selectivity of the chemosensor. Three different DUL-nanoMIPs and non-imprinted polymer (nanoNIPs) were prepared with these monomers. DUL-nanoMIPs, synthesized from respective methacrylic acid and ethylene glycol dimethyl acrylate as the functional and cross-linking monomers, revealed the highest affinity to the DUL analyte. The linear dynamic concentration range, extending from 10 pM to 676 nM DUL, and the limit of detection (LOD), equaling 1.6 pM, in the plasma were determined by the DPV chemosensor, outperforming the EIS chemosensor. HPLC-UV measurements confirmed the results of DUL electrochemical chemosensing.

Early Biological Modulations Resulting from 1-Week Venlafaxine Exposure of Marine Mussels Mytilus galloprovincialis Determined by a Metabolomic Approach

There is growing evidence of the presence of pharmaceuticals in natural waters and their accumulation in aquatic organisms. While their mode of action on non-target organisms is still not clearly understood, their effects warrant assessment. The present study assessed the metabolome of the Mediterranean mussel (Mytilus galloprovincialis) exposed to a 10 µg/L nominal concentration of the antidepressant venlafaxine (VLF) at 3 time-points (1, 3, and 7 days). Over the exposure period, we observed up- or down-modulations of 113 metabolites, belonging to several metabolisms, e.g., amino acids (phenylalanine, tyrosine, tryptophan, etc.), purine and pyrimidine metabolisms (adenosine, cyclic AMP, thymidine, etc.), and several other metabolites involved in diverse functions. Serotonin showed the same time-course modulation pattern in both male and female mussels, which was consistent with its mode of action in humans, i.e., after a slight decrease on the first day of exposure, its levels increased at day 7 in exposed mussels. We found that the modulation pattern of impacted metabolites was not constant over time and it was gender-specific, as male and female mussels responded differently to VLF exposure.

Metabolism of a Selective Serotonin and Norepinephrine Reuptake Inhibitor Duloxetine in Liver Microsomes and Mice

Duloxetine (DLX) is a dual serotonin and norepinephrine reuptake inhibitor, widely used for the treatment of major depressive disorder. Although DLX has shown good efficacy and safety, serious adverse effects (e.g., liver injury) have been reported. The mechanisms associated with DLX-induced toxicity remain elusive. Drug metabolism plays critical roles in drug safety and efficacy. However, the metabolic profile of DLX in mice is not available, although mice serve as commonly used animal models for mechanistic studies of drug-induced adverse effects. Our study revealed 39 DLX metabolites in human/mouse liver microsomes and mice. Of note, 13 metabolites are novel, including five N-acetyl cysteine adducts and one reduced glutathione (GSH) adduct associated with DLX. Additionally, the species differences of certain metabolites were observed between human and mouse liver microsomes. CYP1A2 and CYP2D6 are primary enzymes responsible for the formation of DLX metabolites in liver microsomes, including DLX-GSH adducts. In summary, a total of 39 DLX metabolites were identified, and species differences were noticed in vitro. The roles of CYP450s in DLX metabolite formation were also verified using human recombinant cytochrome P450 (P450) enzymes and corresponding chemical inhibitors. Further studies are warranted to address the exact role of DLX metabolism in its adverse effects in vitro (e.g., human primary hepatocytes) and in vivo (e.g., Cyp1a2-null mice). SIGNIFICANCE STATEMENT: This current study systematically investigated Duloxetine (DLX) metabolism and bioactivation in liver microsomes and mice. This study provided a global view of DLX metabolism and bioactivation in liver microsomes and mice, which are very valuable to further elucidate the mechanistic study of DLX-related adverse effects and drug-drug interaction from metabolic aspects.

Recent developments in the management of Huntington's disease

Huntington's disease (HD) is a rare, incurable, inheritedneurodegenerative disorder manifested by chorea, hyperkinetic, and hypokinetic movements. The FDA has approved only two drugs, viz. tetrabenazine, and deutetrabenazine, to manage the chorea associated with HD. However, several other drugs are used as an off-label to manage chorea and other symptoms such as depression, anxiety, muscle tremors, and cognitive dysfunction associated with HD. So far, there is no disease-modifying treatment available. Drug repurposing has been a primary drive to search for new anti-HD drugs. Numerous molecular targets along with a wide range of small molecules and gene therapies are currently under clinical investigation. More than 200 clinical studies are underway for HD, 75% are interventional, and 25% are observational studies. The present review discusses the small molecule clinical pipeline and molecular targets for HD. Furthermore, the biomarkers, diagnostic tests, gene therapies, behavioral and observational studies for HD were also deliberated.

Comparing newborn outcomes after prenatal exposure to individual antidepressants: A retrospective cohort study

OBJECTIVE

To compare associations between individual antidepressants and newborn outcomes.

DESIGN

Retrospective cohort study.

SETTING

Deliveries in a large, US medical system.

POPULATION

Women who received at least one antidepressant prescription 3 months prior to conception through delivery.

METHODS

Eligible women had maternal characteristics and newborn outcomes extracted from medical record data. Exposure was defined by the timing of the prescription during pregnancy.

MAIN OUTCOME MEASURES

Newborn outcomes (any adaptation syndrome, neonatal intensive care unit (NICU) admission) were analyzed for each antidepressant and compared using standard statistics and multivariable regression compared to exposure to bupropion. Odds of outcomes based on timing of exposure were also explored.

RESULTS

A total of 3,694 women were analyzed. Rates of any adaptation syndrome (p < 0.001), NICU admission (p < 0.001), and transient tachypnea of newborn (TTN) (p = 0.006) were significantly different between drugs. Infants exposed to duloxetine had the highest rates of NICU admissions (39.6%) and adaptation syndromes (15.1%). Venlafaxine-exposed infants had the highest rates of TTN (18.2%). Controlling for maternal age, race, insurance, and gestational age at delivery, early pregnancy antidepressant exposure was associated with adaptation syndrome and NICU admission for both duloxetine (adjusted odds ratio (aOR) 2.31 [95% Confidence Interval (CI) 1.11-4.80] and aOR 2.47 [95% CI 1.40-4.34], respectively) and escitalopram (aOR 1.72 [95% CI 1.09-2.70] and aOR 1.64 [95% CI 1.21-2.22], respectively). Exposure in the third trimester was associated with any adaptation syndrome for citalopram, duloxetine, escitalopram, fluoxetine, sertraline, and venlafaxine and NICU admission for bupropion, citalopram, duloxetine, escitalopram, and fluoxetine.

CONCLUSION

Duloxetine and escitalopram appear to have the strongest associations with any adaptation syndrome and NICU admission whereas bupropion and sertraline tended to have among the lowest risks of these outcomes. These results can help providers and patients discuss choice of individual antidepressant drugs during pregnancy.

Duloxetine versus 'active' placebo, placebo or no intervention for major depressive disorder; a protocol for a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

BACKGROUND

Major depression significantly impairs quality of life, increases the risk of suicide, and poses tremendous economic burden on individuals and societies. Duloxetine, a serotonin norepinephrine reuptake inhibitor, is a widely prescribed antidepressant. The effects of duloxetine have, however, not been sufficiently assessed in earlier systematic reviews and meta-analyses.

METHODS/DESIGN

A systematic review will be performed including randomised clinical trials comparing duloxetine with 'active' placebo, placebo or no intervention for adults with major depressive disorder. Bias domains will be assessed, an eight-step procedure will be used to assess if the thresholds for clinical significance are crossed. We will conduct meta-analyses. Trial sequential analysis will be conducted to control random errors, and the certainty of the evidence will be assessed using GRADE. To identify relevant trials, we will search Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, PsycINFO, Science Citation Index Expanded, Social Sciences Citation Index, Conference Proceedings Citation Index-Science and Conference Proceedings Citation Index-Social Science & Humanities. We will also search Chinese databases and Google Scholar. We will search all databases from their inception to the present. Two review authors will independently extract data and perform risk of bias assessment. Primary outcomes will be the difference in mean depression scores on Hamilton Depression Rating Scale between the intervention and control groups and serious adverse events. Secondary outcomes will be suicide, suicide-attempts, suicidal ideation, quality of life and non-serious adverse events.

DISCUSSION

No former systematic review has systematically assessed the beneficial and harmful effects of duloxetine taking into account both the risks of random errors and the risks of systematic errors. Our review will help clinicians weigh the benefits of prescribing duloxetine against its adverse effects and make informed decisions.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2016 CRD42016053931.

Comparison of risk of cardiovascular disease related adverse events between selective serotonin reuptake inhibitor users and serotonin norepinephrine reuptake inhibitor users in Korean adult patients with depression: retrospective cohort study

Serotonin norepinephrine reuptake inhibitor (SNRI) has been increasingly administered, but the associated cardiovascular disease (CVD) related adverse events risk is not clearly understood. So, we conducted a cohort study to identified CVD-related adverse events risk of SNRI comparing to selective serotonin reuptake inhibitor (SSRI). We used Korea Health Insurance Review and Assessment data. During the period from April 2009 to March 2011, patients who were prescribed SSRI or SNRI for depression, who were followed up till March 2018, were the subjects. Hemorrhagic stroke, ischemic stroke, and myocardial infarction were selected as the outcomes. High-dimensional propensity scores were used to adjust the unmeasured confounders. the cox proportional hazard model was used for the statistical analysis. A total of 1,016,136 patients diagnosed with depression over the age of 20 were screened and there were 64,739 SSRI users and 3,711 SNRI users in the group of patients. The adjusted hazard ratio did not differ between the two groups, but the subgroup analysis according to comorbidities showed a high risk of hemorrhagic stroke in SNRI users with hypertension or diabetes mellitus.

Acceptability of escitalopram versus duloxetine in outpatients with depression who did not respond to initial second-generation antidepressants: A randomized, parallel-group, non-inferiority trial

BACKGROUNDS

Antidepressants are widely used to treat major depressive disorder. First-line treatments with antidepressants are only successful in one-third of patients; however, evidence from randomized controlled trials on second-line treatments is limited. Moreover, recently acceptability is suggested to be a good indicator of overall treatment success.

METHODS

This is a multi-center two-arm, three-phased randomized controlled trial performed in Japan from December 2013 to March 2017 comparing the acceptability of escitalopram and duloxetine as a second-line drug. Patients, who failed to respond to antidepressants such as sertraline, paroxetine, fluvoxamine, milnacipran or mirtazapine for at least 3 weeks, were randomized to either escitalopram (Group A) or duloxetine (Group B) in Step 1 (8 weeks). In Step 2 (8 weeks), the drug was switched to the other if the first drug failed. The discontinuation rate at the end of Step 1 was the primary endpoint and non-inferiority of escitalopram vs duloxetine was tested. In addition, change in clinical measures from baseline were also assessed at the end of Step 1, 2 and up to 52 weeks.

RESULTS

At the end of Step 1, Group A (n = 82) was significantly superior to Group B (n = 78) in discontinuation rate (4.9% to 19.2%, P = 0.007). The change in clinical indices from baseline were not different between the groups at either timepoint.

LIMITATIONS

As the major reason for discontinuation in Group B was the "withdrawal of consent" the concrete reason could not be verified.

CONCLUSIONS

As a second-line treatment drug, escitalopram was suggested to be non-inferior to duloxetine in acceptability.

TRIAL REGISTRATION

UMINCTR(UMIN000012367), registered on December 1st, 2013 and last updated on April 4th, 2017.

GW117: A novel serotonin (5-HT2C ) receptor antagonist and melatonin (MT1 /MT2 ) receptor agonist with potential antidepressant-like activity in rodents

Aims

To evaluate the antidepressant‐like effect of compound GW117 in rodents using in vitro binding and uptake assays as well in vivo behavioral tests.

Methods

We investigated the target profile of GW117 using [³⁵S]‐GTPγS and [³H]PIP binding. Using the forced swimming test and chronic unpredictable stress in rats, tail suspension test in mice and rats, and learned helplessness model in mice, we further revealed the antidepressant‐like and anxiolytic‐like effects of GW117.

Results

The current study suggests that GW117 displays serotonin 2C (5‐HT_2C) receptor antagonist and melatonin type 1 and 2 (MT₁/MT₂) receptor agonist properties, as well as evident antidepressant and anxiolytic effects.

Conclusion

These data suggest that GW117 is probably a potent antidepressant.

Brain Targeting of Duloxetine HCL via Intranasal Delivery of Loaded Cubosomal Gel: In vitro Characterization, ex vivo Permeation, and in vivo Biodistribution Studies

Purpose

Duloxetine (DLX) is dual serotonin and norepinephrine reuptake inhibitor suffering from limited bioavailability (≈ 40%) due to extensive hepatic metabolism. This work aims to formulate and evaluate DLX intranasal thermoreversible cubosomal gels to enhance its bioavailability and ensure efficient brain targeting.

Materials and Methods

Cubo-gels were prepared by 3³ central composite design with three independent factors, lipid ratio (glycerol monooleate: glycerol tripalmitate), Pluronic F127%, and Pluronic F68%. The prepared formulations were evaluated for their particle size (PS), gelling temperature (GT), entrapment efficiency (EE%), and in vitro release. The cubo-gel with the highest desirability (0.88) was chosen as the optimized formulation. DLX cubo-gel was evaluated using differential scanning calorimetry, Fourier-transform infrared spectroscopy, X-ray powder diffraction, and transmission electron microscopy. Cytotoxicity study, ex vivo permeation study and in vivo bio-distribution study were conducted to evaluate the safety and efficacy of brain targeting.

Results

The optimum cubo-gel was composed of 3.76 lipid ratio, 20% w/v PF127, and 5% w/v PF68. It had PS of 265.13 ± 9.85 nm, GT of 32 ± 0.05°C, EE% of 98.13 ± 0.50%, and showed controlled release behavior where 33% DLX was released within 6 hrs. The plain in situ cubo-gel had a significantly higher IC₅₀ compared to DLX solution and DLX-loaded in situ cubo-gel. The ex vivo permeation study showed 1.27 enhancement in the drug permeation from DLX in situ cubo-gel. According to the in vivo bio-distribution study in plasma and brain, the intranasal DLX in situ cubo-gel showed a 1.96 fold improvement in brain bioavailability compared to the intranasal solution. Its BTE% and DTP% were 137.77 and 10.5, respectively, indicating efficient brain targeting after intranasal administration.

Conclusion

Accordingly, intranasal DLX in situ cubo-gel can be considered as an innovative nano-carrier delivery system for bioavailability enhancement and efficient brain targeting of DLX to maximize its effect.

Antidepressant Medications and Weight Change: A Narrative Review

Antidepressant medications are the first-line treatment option for moderate to severe major depressive disorder. However, most antidepressants have numerous documented adverse events, including cardiometabolic effects and weight gain, which are major public health concerns. Antidepressant agents provide varying risk of associated weight gain, including significant within-class differences. Some agents, such as mirtazapine, show significant levels of weight gain, while others, such as bupropion, demonstrate weight-loss effects. Current findings suggest the role of histamine and serotonin off-target appetite-promoting pathways in adverse weight-gain effects. Therefore, controlling for undesired weight effects is an important consideration for the selection of antidepressants.

Neuropharmacological and antidepressant-like effects of ZY-1408: A novel serotonin/norepinephrine reuptake inhibitor and serotonin receptor 2C antagonist

Depression is a common mental illness and leading cause of disability. Most current antidepressants are associated with significant limitations, and in particular, a delayed onset and low rate of efficacy. Consequently, there remains an ongoing need for antidepressants that are either more effective or better tolerated than existing standards. We previously identified ZY-1408 as a drug with a novel chemical structure and potential anti-depressant-like activity. Specifically, ZY-1408 is a novel serotonin 2C (5-HT_2C) receptor antagonist and serotonin/norepinephrine (5-HT/NE) reuptake inhibitor. In this study, we further investigated the antidepressant-like efficacy of ZY-1408 using in vitro and in vivo behavioral tests. ZY-1408 showed 5-HT_2C receptor antagonist and 5-HT/NE reuptake inhibitor properties in vitro. Meanwhile, ZY-1408 decreased immobility in vivo in a dose-dependent manner in rats (via the forced-swim test) and mice (via the tail-suspension test). The behavioral test results do not appear to result from stimulation of locomotor activity. In chronically stressed rats, repeated ZY-1408 treatment significantly reversed depressive-like behavior, including reduced sucrose preference, decreased locomotor activity, and prolonged time to begin eating. Furthermore, in vivo microdialysis showed that administration of ZY-1408 significantly increased extracellular concentrations of 5-HT and NE in the hippocampus of freely moving rats. Thus, ZY-1408 is a potent and orally active 5-HT_2C receptor antagonist and 5-HT/NE reuptake inhibitor with antidepressant-like activity in rodents.

Recent Advances and Challenges of the Drugs Acting on Monoamine Transporters

Background:

The human Monoamine Transporters (hMATs), primarily including hSERT, hNET and hDAT, are important targets for the treatment of depression and other behavioral disorders with more than the availability of 30 approved drugs.

Objective:

This paper is to review the recent progress in the binding mode and inhibitory mechanism of hMATs inhibitors with the central or allosteric binding sites, for the benefit of future hMATs inhibitor design and discovery. The Structure-Activity Relationship (SAR) and the selectivity for hit/lead compounds to hMATs that are evaluated by in vitro and in vivo experiments will be highlighted.

Methods:

PubMed and Web of Science databases were searched for protein-ligand interaction, novel inhibitors design and synthesis studies related to hMATs.

Results:

Literature data indicate that since the first crystal structure determinations of the homologous bacterial Leucine Transporter (LeuT) complexed with clomipramine, a sizable database of over 100 experimental structures or computational models has been accumulated that now defines a substantial degree of structural variability hMATs-ligands recognition. In the meanwhile, a number of novel hMATs inhibitors have been discovered by medicinal chemistry with significant help from computational models.

Conclusion:

The reported new compounds act on hMATs as well as the structures of the transporters complexed with diverse ligands by either experiment or computational modeling have shed light on the poly-pharmacology, multimodal and allosteric regulation of the drugs to transporters. All of the studies will greatly promote the Structure-Based Drug Design (SBDD) of structurally novel scaffolds with high activity and selectivity for hMATs.

Amitifadine, a triple reuptake inhibitor, reduces self-administration of the opiate remifentanil in rats

RATIONALE

A variety of neural systems are involved in drug addiction, and some of these systems are shared across different addictive drugs. We have found several different types of drug treatments that successfully reduce nicotine self-administration.

OBJECTIVES

The current set of studies is the first in a series to determine if drug treatments that have been found to significantly reduce nicotine self-administration would reduce opiate self-administration.

METHODS

Amitifadine, a triple reuptake inhibitor of dopamine, norepinephrine, and serotonin, was assessed in female Sprague-Dawley rats to determine whether it significantly reduces remifentanil self-administration with either acute or chronic treatment.

RESULTS

Acutely, amitifadine doses of 5, 10, and 20 mg/kg each significantly reduced remifentanil self-administration. In a chronic study, repeated treatment with 10 mg/kg of amitifadine continued to reduce remifentanil self-administration, even after the cessation of treatment. However, amitifadine was not found to attenuate the rise in remifentanil self-administration with continued access. This study and our earlier one showed that the 10 mg/kg amitifadine dose did not significantly affect food motivated responding. Amitifadine did not attenuate remifentanil-induced antinociception as measured on the hot plate test but extended and maintained antinociceptive effects.

CONCLUSIONS

These studies show the promise of amitifadine as a treatment for countering opiate self-administration for adjunctive use with opioids for analgesia. Further studies are needed to determine the possible efficacy of amitifadine for combating opiate addiction or preventing it in humans during adjunctive use with opioids for chronic pain.

Platinum-induced peripheral neurotoxicity: From pathogenesis to treatment

Platinum-induced peripheral neurotoxicity (PIPN) is a common side effect of platinum-based chemotherapy that may cause dose reduction and discontinuation, with oxaliplatin being more neurotoxic. PIPN includes acute neurotoxicity restricted to oxaliplatin, and chronic non-length-dependent sensory neuronopathy with positive and negative sensory symptoms and neuropathic pain in both upper and lower limbs. Chronic sensory axonal neuropathy manifesting as stocking-and-glove distribution is also frequent. Worsening of neuropathic symptoms after completing the last chemotherapy course may occur. Motor and autonomic involvement is uncommon. Ototoxicity is frequent in children and more commonly to cisplatin. Platinum-based compounds result in more prolonged neuropathic symptoms in comparison to other chemotherapy agents. Patient reported outcomes questionnaires, clinical evaluation and instrumental tools offer complementary information in PIPN. Electrodiagnostic features include diffusely reduced/abolished sensory action potentials, in keeping with a sensory neuronopathy. PIPN is dependent on cumulative dose but there is a large variability in its occurrence. The search for additional risk factors for PIPN has thus far yielded no consistent findings. There are currently no neuroprotective strategies to reduce the risk of PIPN, and symptomatic treatment is limited to duloxetine that was found effective in a single phase III intervention study. This review critically examines the pathogenesis, incidence, risk factors (both clinical and pharmacogenetic), clinical phenotype and management of PIPN.

Effect of Antidepressants on Psychotic Symptoms in Parkinson Disease: A Review of Case Reports and Case Series

OBJECTIVES

The treatment of Parkinson disease (PD) psychosis remains a challenge. Only a few treatments eliciting significant relief of psychotic symptoms have passed the test of randomized controlled trials.

METHODS

Here, we conducted a review of the literature on the effect of antidepressants on PD psychosis. Because there is no randomized controlled trial that assessed the antipsychotic effects of antidepressants in PD, only case reports, case series, and open-label trials were available to review. Because of the scarce literature, statistical analysis could not be performed.

RESULTS

The following antidepressants alleviated hallucinations in PD: amoxapine, citalopram, clomipramine, escitalopram, mianserin, mirtazapine, and venlafaxine. The antidepressants were generally well tolerated, with the exception of amoxapine, which exacerbated parkinsonism.

CONCLUSIONS

Whereas the conclusions that can be drawn on the efficacy of antidepressants at reducing PD psychosis are limited because of the poor quality of the reported studies, it is encouraging to notice that there are positive anecdotal reports. Further studies are needed to confirm the potential of these drugs and also to determine if a subtype of patients or of psychotic features may be more likely to be improved by antidepressants.

ADHD with Comorbid Bipolar Disorders: A Systematic Review of Neurobiological, Clinical and Pharmacological Aspects Across the Lifespan

BACKGROUND

Attention deficit hyperactivity (ADHD) disorder is a neurodevelopmental disorder characterized by inattention, hyperactivity, disruptive behaviour, and impulsivity. Despite considered typical of children for a long time, the persistence of ADHD symptoms in adulthood gained increasing interest during the last decades. Indeed, its diagnosis, albeit controversial, is rarely carried out even because ADHD is often comorbid with several other psychiatric diosrders, in particular with bipolar disorders (BDs), a condition that complicates the clinical picture, assessment and treatment.

AIMS

The aim of this paper was to systematically review the scientific literature on the neurobiological, clinical features and current pharmacological management of ADHD comorbid with BDs across the entire lifespan, with a major focus on the adulthood.

DISCUSSION

The pharmacology of ADHD-BD in adults is still empirical and influenced by the individual experience of the clinicians. Stimulants are endowed of a prompt efficacy and safety, whilst non-stimulants are useful when a substance abuse history is detected, although they require some weeks in order to be fully effective. In any case, an in-depth diagnostic and clinical evaluation of the single individual is mandatory.

CONCLUSION

The comorbidity of ADHD with BD is still a controversial matter, as it is the notion of adult ADHD as a distinct nosological category. Indeed, some findings highlighted the presence of common neurobiological mechanisms and overlapping clinical features, although disagreement does exist. In any case, while expecting to disentangle this crucial question, a correct management of this comorbidity is essential, which requires the co-administration of mood stabilizers. Further controlled clinical studies in large samples of adult ADHD-BD patients appear extremely urgent in order to better define possible therapeutic guidelines, as well as alternative approaches for this potentially invalidating condition.

Molecular docking utilising the OliveNet™ library reveals novel phenolic compounds which may potentially target key proteins associated with major depressive disorder

The antidepressant medications that are currently prescribed to patients suffering from major depressive disorder (MDD) have limitations and as a result, there is an urgent need to increase the options that are available. A number of studies have found that natural polyphenols have neuroprotective properties and there is evidence to suggest that they modulate neurotransmitter systems. There are more than 200 phenolic compounds that have been identified in Olea europaea, many of which have not yet been investigated for their potential biological effects. In this study, in silico methods were used to screen the phenolic library from the OliveNet™ database and identify novel lead compounds for proteins implicated in the pathophysiology of MDD. The molecular docking results revealed that the monoamine oxidase enzyme isoforms (MAO-A/MAO-B) had binding specificities for certain phenolic subclasses. The lead ligands that were identified from these subclasses were positioned near the flavin adenine dinucleotide (FAD) cofactor, interacting in a similar manner as known inhibitors. In addition to the MAO enzymes, several phenolic compounds were docked to neurotransmitter transporters and postsynaptic receptors, as well as proteins involved in neuroinflammation, oxidative stress and the endocannabinoid system. Based on the binding affinity, position, orientation and interactions of the lead phenolic compounds identified in this study, it is predicted that they may have antidepressant properties. The results should be validated further using molecular dynamics (MD) simulations, as well as in vivo and in vitro techniques.

Development of Obsessive-Compulsive Symptoms Following Abrupt Discontinuation of Venlafaxine

Withdrawal symptoms after discontinuation of antidepressants are common and have long been known. Typical symptoms after dose reduction or discontinuation of antidepressants are dizziness, drowsiness, headache, flu-like symptoms, hyperarousal, imbalance, insomnia, irritability, and nausea. Rebound, relapse, or recurrence associated with the underlying mental disorder may also occur. The occurrence of obsessive-compulsive symptoms (OCS) following abrupt discontinuation of antidepressants have not yet been reported. Here we report the development of OCS (obsessional suicidal thoughts) in a patient with major depressive disorder and absence of a previous obsessive-compulsive disorder following abrupt discontinuation of venlafaxine. Treatment with escitalopram facilitated remission of OCS. We discuss a possible causal link between abrupt discontinuation of venlafaxine and development of OCS under consideration of pathophysiologic aspects regarding obsessive compulsive disorders, the chronological sequence of symptoms in the present case, and pharmacodynamic and -kinetic aspects. Our case report suggests the possibility of the occurrence of obsessive-compulsive symptoms following abrupt discontinuation of venlafaxine.

Predicting Treatment Outcome in Major Depressive Disorder Using Serotonin 4 Receptor PET Brain Imaging, Functional MRI, Cognitive-, EEG-Based, and Peripheral Biomarkers: A NeuroPharm Open Label Clinical Trial Protocol

BACKGROUND

Between 30 and 50% of patients with major depressive disorder (MDD) do not respond sufficiently to antidepressant regimens. The conventional pharmacological treatments predominantly target serotonergic brain signaling but better tools to predict treatment response and identify relevant subgroups of MDD are needed to support individualized and mechanistically targeted treatment strategies. The aim of this study is to investigate antidepressant-free patients with MDD using neuroimaging, electrophysiological, molecular, cognitive, and clinical examinations and evaluate their ability to predict clinical response to SSRI treatment as individual or combined predictors.

METHODS

We will include 100 untreated patients with moderate to severe depression (>17 on the Hamilton Depression Rating Scale 17) in a non-randomized open clinical trial. We will collect data from serotonin 4 receptor positron emission tomography (PET) brain scans, functional magnetic resonance imaging (fMRI), electroencephalogram (EEG), cognitive tests, psychometry, and peripheral biomarkers, before (at baseline), during, and after 12 weeks of standard antidepressant treatment. Patients will be treated with escitalopram, and in case of non-response at week 4 or intolerable side effects, offered to switch to a second line treatment with duloxetine. Our primary outcome (treatment response) is assessed using the Hamilton depression rating subscale 6-item scores at week 8, compared to baseline. In a subset of the patients (n = ~40), we will re-assess the neurobiological response (using PET, fMRI, and EEG) 8 weeks after initiated pharmacological antidepressant treatment, to map neurobiological signatures of treatment responses. Data from matched controls will either be collected or is already available from other cohorts.

DISCUSSION

The extensive investigational program with follow-up in this large cohort of participants provides a unique possibility to (a) uncover potential biomarkers for antidepressant treatment response, (b) apply the findings for future stratification of MDD, (c) advance the understanding of pathophysiological underpinnings of MDD, and (d) uncover how putative biomarkers change in response to 8 weeks of pharmacological antidepressant treatment. Our data can pave the way for a precision medicine approach for optimized treatment of MDD and also provides a resource for future research and data sharing.

CLINICAL TRIAL REGISTRATION

The study was registered at clinicaltrials.gov prior to initiation (NCT02869035; 08.16.2016, URL: https://clinicaltrials.gov/ct2/results?cond=&term=NCT02869035&cntry=&state=&city=&dist=).

The Druggability of Solute Carriers

The transport of materials across membranes is a vital process for all aspects of cellular function, including growth, metabolism, and communication. Protein transporters are the molecular gates that control this movement and serve as key points of regulation for these processes, thus representing an attractive class of therapeutic targets. With more than 400 members, the solute carrier (SLC) membrane transport proteins are the largest family of transporters, yet, they are pharmacologically underexploited relative to other protein families and many of the available chemical tools possess suboptimal selectivity and efficacy. Fortuitously, there is increased interest in elucidating the physiological roles of SLCs as well as growing recognition of their therapeutic potential. This Perspective provides an overview of the SLC superfamily, including their biochemical and functional features, as well as their roles in various human diseases. In particular, we explore efforts and associated challenges toward drugging SLCs, as well as highlight opportunities for future drug discovery.

CYP2D1 Gene Knockout Reduces the Metabolism and Efficacy of Venlafaxine in Rats

Rat CYP2D1 has been considered as an ortholog of human CYP2D6 To assess the role of CYP2D1 in physiologic processes and drug metabolism, a CYP2D1-null rat model was generated with a CRISPR/Cas9 method. Seven base pairs were deleted from exon 4 of CYP2D1 of Sprague-Dawley wild-type (WT) rats. The CYP2D1-null rats were viable and showed no abnormalities in general appearance and behavior. The metabolism of venlafaxine (VLF) was further studied in CYP2D1-null rats. The V _max and intrinsic clearance of the liver microsomes in vitro from CYP2D1-null rats were decreased (by ∼46% and ∼57% in males and ∼47% and ∼58% in females, respectively), while the Michaelis constant was increased (by ∼24% in males and ∼25% in females) compared with WT rats. In the pharmacokinetic studies, compared with WT rats, VLF in CYP2D1-null rats had significantly lower apparent total clearance and apparent volume of distribution (decreased by ∼36% and ∼48% in males and ∼23% and ∼25% in females, respectively), significantly increased area under the curve (AUC) from the time of administration to the last time point, AUC from the start of administration to the theoretical extrapolation, and C _max (increased by ∼64%, ∼59%, and ∼26% in males and ∼43%, ∼35%, and ∼15% in females, respectively). In addition, O-desmethyl venlafaxine formation was reduced as well in CYP2D1-null rats compared with that in WT rats. Rat depression models were developed with CYP2D1-null and WT rats by feeding them separately and exposing them to chronic mild stimulation. VLF showed better efficacy in the WT depression rats compared with that in the CYP2D1-null rats. In conclusion, a CYP2D1-null rat model was successfully generated, and CYP2D1 was found to play a certain role in the metabolism and efficacy of venlafaxine. SIGNIFICANCE STATEMENT: A novel CYP2D1-null rat model was generated using CRISPR/Cas9 technology, and it was found to be a valuable tool in the study of the in vivo function of human CYP2D6. Moreover, our data suggest that the reduced O-desmethyl venlafaxine formation was associated with a lower VLF efficacy in rats.

Acceptability of escitalopram versus duloxetine in outpatients with depression who did not respond to initial second-generation antidepressants: Study protocol for a randomized, parallel-group, non-inferiority trial

Aim

The purpose of this study is to compare acceptability of two second generation antidepressants for major depressive disorder patients who have not responded to the first antidepressant for current episode. We will investigate the treatment discontinuation rate and treatment adherence as well as incidence of adverse events in order to evaluate safety.

Methods

This is a two‐arm, three‐phased randomized controlled trial in which independent assessors will be blinded while treating psychiatrists and patients remain unblinded to treatment allocation. Patients will be randomized to escitalopram or duloxetine in Step 1 (8 weeks), and when entering Step 2 (8 weeks), the drug will be switched to the other if the first one is not effective at the end of Step 1. The acceptability of the allocated drugs, improvements in depression from baseline, adverse events, and attrition rates will be recorded and assessed for up to 52 weeks, including the follow‐up step.

Results

It is going to be disseminated via our following reports or presentations.

Conclusions

This study will provide valuable information for clinicians who encounter patients who failed to respond to their first treatment.

This is a protocol of randomized controlled trial assessing acceptability of two antidepressants after one antidepressant therapy failed.

Psychotropic Drugs for the Management of Chronic Pain and Itch

Clinical observations have shown that patients with chronic neuropathic pain or itch exhibit symptoms of increased anxiety, depression and cognitive impairment. Such patients need corrective therapy with antidepressants, antipsychotics or anticonvulsants. It is known that some psychotropic drugs are also effective for the treatment of neuropathic pain and pruritus syndromes due to interaction with the secondary molecular targets. Our own clinical studies have identified antipruritic and/or analgesic efficacy of the following compounds: tianeptine (atypical tricyclic antidepressant), citalopram (selective serotonin reuptake inhibitor), mianserin (tetracyclic antidepressant), carbamazepine (anticonvulsant), trazodone (serotonin antagonist and reuptake inhibitor), and chlorprothixene (antipsychotic). Venlafaxine (serotonin-norepinephrine reuptake inhibitor) is known to have an analgesic effect too. The mechanism of such effect of these drugs is not fully understood. Herein we review and correlate the literature data on analgesic/antipruritic activity with pharmacological profile of these compounds.

A comparative double-blind randomized study on the effectiveness of Duloxetine and Gabapentin on painful diabetic peripheral polyneuropathy

Background: The most common cause of polyneuropathy is diabetes mellitus. Neuropathic pain is seen in 26% of diabetic population. Therapeutic techniques for this disease can become challenging. Method: This study was a prospective comparative double-blind randomized study which was conducted during an eight-week period. Totally, 104 painful diabetic peripheral polyneuropathy (PDPP) patients who had a minimum Visual Analog Scale (VAS) of 40 millimeters, received no pain-controlling medication, and had no other severe disease at its final stage were randomly assigned to two groups (n=52) through the four block method. One group received Duloxetine and the other received Gabapentin. The effectiveness was measured through primary effectiveness (VAS scale) and secondary effectiveness (Sleep Interference Score, and Clinical Global Impression of Change (CGIC)). Medication compliance was assessed by enumerating the number of patients who refused treatment because of side effects. The Fisher's exact T-test and ANOVA were used for data analysis. This study was approved by the Ethics Committee of Jundishapur, University of Medical sciences Ahvaz, Iran, under reference number: IR.AJUMS.REC.1395.78. In addition, this study was registered and approved in the Iranian Registry of Clinical Trials (IRCT ID: IRCT20161023030455N2) (http://irct.ir/). Results: VAS, Sleep Interference Score, and CGIC were significantly improved (P<0.05) through time in both groups, [For GBP: VAS^Baseline=64±20.03, VAS^week1=55.32±18.76, VAS^week4=44.68±15.82, VAS^week8=39.43±14.32; For DLX: VAS^Base-line=62±21.18, VAS^week1=58.76±20.37, VAS^week4=45.84±16.21, VAS^week8=36.78±15.62] while a significant difference between the two groups was not observed (P<0.05). However, such significant improvements were not observed in the Duloxetine group at the end of the first week (P=674). Improvement in Sleep Interference Score and CGIC were similar to the results for the VAS scale. Side effects in the Duloxetine group (n=2) compared to the Gabapentin group (n=9) were significantly less (P<0.001). As a result, medication acceptance in the Duloxetine group (n=47) was significantly better than the Gabapentin (n=41) group (P<0.001). Conclusion: Both Duloxetine and Gabapentin are effective for the treatment of PDPP. On the one hand, Gabapentin shows the effect earlier while has more side effects. Conversely, Duloxetine has better medication compliance. Trial registration: The method of this study was approved by the Ethics Committee of Jundishapur University of Medical Sciences, Ahvaz, Iran, under reference number: IR.AJUMS.REC.1395.78. In addition, this study was registered and approved in the Iranian Registry of Clinical Trials (IRCT ID: IRCT20161023030455N2) (http://irct.ir/).

Drug-induced endocrine blood pressure elevation

Patients with uncontrolled hypertension are at risk for cardiovascular complications. The majority of them suffers from unidentified forms of hypertension and a fraction has so-called secondary hypertension with an identifiable cause. The patient's medications, its use of certain herbal supplements and over-the-counter agents represent potential causal factors for secondary hypertension that are often overlooked. The current review focuses on drugs that are likely to elevate blood pressure by affecting the human endocrine system at the level of steroid synthesis or metabolism, mineralocorticoid receptor activity, or by affecting the catecholaminergic system. Drugs with known adverse effects but where benefits outweigh their risks, drug candidates and market withdrawals are reviewed. Finally, potential therapeutic strategies are discussed.