Duloxetine: A Dual Serotonin-Norepinephrine Reuptake Inhibitor for Treatment of Major Depressive Disorder

Suspected duloxetine-induced restless legs syndrome phenotypic variant: a case report

BACKGROUND

Restless arms syndrome (RAS) is the most common variant of restless legs syndrome (RLS), which is easy to be ignored in clinical practice due to the lack of specific diagnostic criteria. When effective therapeutic agents induced RAS and symptoms persisted after briefly observation, clinicians will face the challenge of weighing efficacy against side effects.

CASE PRESENTATION

A 67-year-old woman was admitted to a geriatric psychiatric ward with depression. Upon admission, the escitalopram dose was reduced from 15 mg to 10 mg per day, and the duloxetine dose was increased from 60 mg to 80 mg per day. The next night before bedtime, she developed itching and creeping sensations deep inside bilateral shoulders and arms, with the urge to move, worsening at rest, and alleviation after hammering. The symptoms persisted when escitalopram was discontinued. A history of RLS was confirmed. Treatment with 40 mg of duloxetine and 0.125 mg of pramipexole significantly improved depression, and the paresthesia disappeared, with no recurrence occurring 6 months after discharge.

DISCUSSION AND CONCLUSIONS

This case suggests that psychiatrists should pay attention to RLS variants when increasing doses of duloxetine. Long-term improvement can be achieved through dosage reduction combined with dopaminergic drugs instead of immediate discontinuation.

Synthesis of anti-depressant molecules via metal-catalyzed reactions: a review

Depression is one of the most mutilating conditions in the world today. It has been difficult to make advancements toward better, more effective therapies since the introduction of antidepressant medicines in the late 1950s. One important field of medicinal chemistry is the synthesis of antidepressant molecules through metal-catalyzed procedures. The important role that different transition metals, including iron, nickel, ruthenium, and others, serve as catalysts in the synthesis of antidepressants is examined in this review. Key structural motifs included in antidepressant drugs such as tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and others can be synthesized in a variety of effective ways using metal-catalyzed steps. This review examines current developments in the catalytic synthesis of antidepressants and their potential application over the previous thirteen years.

Insight and Recommendations for Fragile X-Premutation-Associated Conditions from the Fifth International Conference on FMR1 Premutation

The premutation of the fragile X messenger ribonucleoprotein 1 (FMR1) gene is characterized by an expansion of the CGG trinucleotide repeats (55 to 200 CGGs) in the 5' untranslated region and increased levels of FMR1 mRNA. Molecular mechanisms leading to fragile X-premutation-associated conditions (FXPAC) include cotranscriptional R-loop formations, FMR1 mRNA toxicity through both RNA gelation into nuclear foci and sequestration of various CGG-repeat-binding proteins, and the repeat-associated non-AUG (RAN)-initiated translation of potentially toxic proteins. Such molecular mechanisms contribute to subsequent consequences, including mitochondrial dysfunction and neuronal death. Clinically, premutation carriers may exhibit a wide range of symptoms and phenotypes. Any of the problems associated with the premutation can appropriately be called FXPAC. Fragile X-associated tremor/ataxia syndrome (FXTAS), fragile X-associated primary ovarian insufficiency (FXPOI), and fragile X-associated neuropsychiatric disorders (FXAND) can fall under FXPAC. Understanding the molecular and clinical aspects of the premutation of the FMR1 gene is crucial for the accurate diagnosis, genetic counseling, and appropriate management of affected individuals and families. This paper summarizes all the known problems associated with the premutation and documents the presentations and discussions that occurred at the International Premutation Conference, which took place in New Zealand in 2023.

Ketamine and the Disinhibition Hypothesis: Neurotrophic Factor-Mediated Treatment of Depression

Ketamine is a promising alternative to traditional pharmacotherapies for major depressive disorder, treatment-resistant depression, and other psychiatric conditions that heavily contribute to the global disease burden. In contrast to the current standard of care medications for these disorders, ketamine offers rapid onset, enduring clinical efficacy, and unique therapeutic potential for use in acute, psychiatric emergencies. This narrative presents an alternative framework for understanding depression, as mounting evidence supports a neuronal atrophy and synaptic disconnection theory, rather than the prevailing monoamine depletion hypothesis. In this context, we describe ketamine, its enantiomers, and various metabolites in a range of mechanistic actions through multiple converging pathways, including N-methyl-D-aspartate receptor (NMDAR) inhibition and the enhancement of glutamatergic signaling. We describe the disinhibition hypothesis, which posits that ketamine's pharmacological action ultimately results in excitatory cortical disinhibition, causing the release of neurotrophic factors, the most important of which is brain-derived neurotrophic factor (BDNF). BDNF-mediated signaling along with vascular endothelial growth factor (VEGF) and insulin-like growth factor 1 (IGF-1) subsequently give rise to the repair of neuro-structural abnormalities in patients with depressive disorders. Ketamine's efficacious amelioration of treatment-resistant depression is revolutionizing psychiatric treatment and opening up fresh vistas for understanding the underlying causes of mental illness.

Iridium-catalyzed enantioselective synthesis of chiral γ-amino alcohols and intermediates of (S)-duloxetine, (R)-fluoxetine, and (R)-atomoxetine

Chiral γ-amino alcohols are the prevalent structural motifs and building blocks in pharmaceuticals and bioactive molecules. Enantioselective hydrogenation of β-amino ketones provides a straightforward and powerful tool for the synthesis of chiral γ-amino alcohols, but the asymmetric transformation is synthetically challenging. Here, a series of tridentate ferrocene-based phosphine ligands bearing modular and tunable unsymmetrical vicinal diamine scaffolds were designed, synthesized, and evaluated in the iridium-catalyzed asymmetric hydrogenation of β-amino ketones. The system was greatly effective to substrates with flexible structure and functionality, and diverse β-tertiary-amino ketones and β-secondary-amino ketones were hydrogenated smoothly. The excellent reactivities and enantioselectivities were achieved in the asymmetric delivery of various chiral γ-amino alcohols with up to 99% yields, >99% ee values, and turnover number (TON) of 48,500. The gram-scale reactions with low catalyst loading showed the potential application in industrial synthesis of chiral drugs, such as (S)-duloxetine, (R)-fluoxetine, and (R)-atomoxetine.

Fragile X Premutation: Medications, Therapy and Lifestyle Advice

The fragile X premutation is characterized by 55–200 CGG repeats in the 5ʹ untranslated region of FMR1, whereas full fragile X mutation has greater than 200 repeats and full methylation, which manifests as fragile X syndrome (FXS). The premutation spectrum of clinical involvement includes fragile X-associated tremor/ataxia syndrome (FXTAS), fragile X-associated primary ovarian insufficiency (FXPOI), and fragile X-associated neuropsychiatric disorders (FXAND). In addition, premutation carriers also suffer from various other health problems such as endocrine abnormalities and autoimmune problems. In this paper, we have discussed different health issues faced by the carriers and interventions including medications, therapy and lifestyle changes that could improve their health.

The Efficacy of Preoperative Duloxetine in Patients Undergoing Major Abdominal Cancer Surgery: A Randomized Controlled Trial

OBJECTIVE

We aimed to evaluate the analgesic efficacy as well as the postoperative quality of recovery of preoperative oral duloxetine a serotonin and norepinephrine reuptake inhibitor for patients undergoing major abdominal cancer surgery.

MATERIALS AND METHODS

Sixty-two patients, undergoing major abdominal cancer surgery were divided into 2 equal groups, received oral duloxetine 60 mg (2 h preoperative) or placebo. Postoperative 48 hours morphine consumption, visual analog scale pain score, and quality of recovery were measured.

RESULTS

The cumulative 48 hours morphine consumption was significantly reduced in the duloxetine group compared with the placebo group (mean±SD) (5.2±3.2 vs. 12.9±3.4 mg), mean difference (95% confidence interval) 7.6 mg (5.9-9.3) P<0.001. The time to first morphine request was delayed significantly in the duloxetine group, median (interquartile range), 25 (19 to 38) versus 8 (4 to 9) hours, P<0.001. The duloxetine group had lower pain scores than the placebo group at 8, 12, 16, and 24 hours postoperatively, however, nonsignificant changes were observed at 0, 2, 4, 36, and 48 hours postoperatively. Participants in the duloxetine group had a better postoperative quality of recovery than the placebo group. The median (interquartile range) of the global quality of recovery-40 scoring system for the duloxetine group was 185 (180 to 191) compared with 170 (163 to 175) in the placebo group (P<0.001).

DISCUSSION

A single preoperative dose of oral duloxetine, 60 mg for patients subjected to major abdominal cancer surgery reduced postoperative pain, decreased opioid consumption, and improved the quality of recovery.

Polymer-based prolonged-release nanoformulation of duloxetine: fabrication, characterization and neuropharmacological assessments

OBJECTIVE

The poly D, L-Lactic-co-glycolic acid (PLGA) and Polycaprolactone (PCL) have been widely applied for developing the prolonged-release formulation. The current study explores the application of these polymers for developing prolonged-release nanosphere of Duloxetine (DLX). Developing a prolonged release parenteral nanosphere formulation of DLX would be overcoming pitfalls like acid-labile degradation, first-pass metabolism and erratic bioavailability along with long-term therapeutic benefit in the treatment of depression.

METHODS

DLX-loaded PLGA and PCL nanospheres were prepared by using the emulsion solvent evaporation technique. The developed formulation was compared with DLX oral solution concerning brain estimation. The prepared nanospheres were subjected to the morphology of the drug particles, polydispersity Index (PDI), distribution size, zeta potential, entrapment efficiency and percentage yield to generate a proof of concept.

RESULTS

DLX-loaded polymeric nanosphere exhibited the uniform size from 89.48 nm to 100.9 nm. The entrapment efficiency was in the range of 74.93 to 77.49, respectively, of PLGA and PCL formulation. The FSEM image affirmed smooth spherical morphology. A good PDI and negative zeta potential value (-31.3 mV for F1 and -30.7 mV for F2) supported the stability of the nanosphere. The brain concentration of the drug was three times enhanced supporting the effectiveness of the nanosphere during pharmacodynamic and pharmacokinetic studies.

CONCLUSION

The intramuscular DLX-loaded nanospheres signify improved brain availability relative to DLX solution. This can be a blueprint for the effective and targeted brain delivery of CNS drugs.

Addressing the Side Effects of Contemporary Antidepressant Drugs: A Comprehensive Review

Randomized trials have shown that selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) have better safety profiles than classical tricyclic antidepressants (TCAs). However, an increasing number of studies, including meta-analyses, naturalistic studies, and longer-term studies suggested that SSRIs and SNRIs are no less safe than TCAs. We focused on comparing the common side effects of TCAs with those of newer generation antidepressants including SSRIs, SNRIs, mirtazapine, and bupropion. The main purpose was to investigate safety profile differences among drug classes rather than the individual antidepressants, so studies containing comparison data on drug groups were prioritized. In terms of safety after overdose, the common belief on newer generation antidepressants having fewer side effects than TCAs appears to be true. TCAs were also associated with higher drop-out rates, lower tolerability, and higher cardiac side-effects. However, evidence regarding side effects including dry mouth, gastrointestinal side effects, hepatotoxicity, seizure, and weight has been inconsistent, some studies demonstrated the superiority of SSRIs and SNRIs over TCAs, while others found the opposite. Some other side effects such as sexual dysfunction, bleeding, and hyponatremia were more prominent with either SSRIs or SNRIs.

Duloxetine loaded-microemulsion system to improve behavioral activities by upregulating serotonin and norepinephrine in brain for the treatment of depression

Duloxetine is a well-known antidepressant molecule which is used in the treatment of depression but due to poor solubility it suffers with the drawback of low oral bioavailability. The objective of present work was to formulate and characterize duloxetine loaded microemulsion to enhance the oral bioavailability. Prepared microemulsion was studied for droplet size, zeta potential, refractive index, polydispersity index (PDI), percentage transmittance, viscosity and in vitro release study. Optimized microemulsion (D1) showed spherical droplets with mean diameter of 35.40 ± 3.11 nm, PDI of 0.170 and zeta potential values of -25.8 mV. Formulation showed good transmittance (greater than 99%), viscosity (0.205 Pa s) and refractive index (1.43 ± 0.01). Increased duloxetine release was obtained with microemulsion in comparison to drug suspension. Behavioral tests like mobility test, tail suspension test and forced swimming test performed in depressed and treated rats with duloxetine microemulsion significantly improved the behavioral activities in comparison to duloxetine suspension. Pharmacokinetic studies showed that microemulsion exhibited 1.8 times increment in bioavailability in comparison to duloxetine suspension.

Treatment of major depressive disorders with generic duloxetine and paroxetine: a multi-centered, double-blind, double-dummy, randomized controlled clinical trial

Background

This study is a pre-registration trial of generic duloxetine that was approved by the China Food and Drug Administration (approval number: 2006L01603).

Aims

Compare the treatment efficacy and safety of generic duloxetine to that of paroxetine in patients with major depressive disorders (MDD).

Methods

This was a double-dummy, double-blind, multicenter, positive drug (paroxetine), parallel randomized controlled clinical trial. The 299 patients with MDD recruited for the study were randomly assigned to use duloxetine (n=149; 40–60 mg/d) or paroxetine (n=150; 20 mg/d) for 8 weeks. The Hamilton Depression rating scale (HAMD-17) was administered at baseline and 1, 2, 4, 6, and 8 weeks after starting treatment. Remission was defined as a HAMD-17 score below 8 at the end of the trial, and treatment effectiveness was defined as a decrease in baseline HAMD-17 score of at least 50% by the end of the trial. Safety was assessed based on the reported prevalence and severity of side effects and changes in laboratory and electrocardiographic findings. Three patients in the duloxetine group dropped out before starting medication, so results were analyzed using a modified intention-to-treat (ITT) method with 146 in the experimental group and 150 in the control group.

Results

Both groups experienced 29 dropouts during the 8-week trial. HAMD-17 scores decreased significantly from baseline throughout the trial in both groups. Based on the ITT analysis, at the end of the trial there was no significant difference between the duloxetine group and the paroxetine group in effectiveness (67.1% v. 71.3%, X²=0.62 p=0.433), remission rate (41.1% v. 51.3%, X²=3.12, p=0.077), or in the incidence of side effects (56.8% v. 54.7%, X²=0.14, p=0.705).

Conclusions

Generic duloxetine is as effective and safe as paroxetine in the acute treatment of patients with MDD who seek care at psychiatric outpatient departments in China.

A selective α2 B adrenoceptor agonist (A-1262543) and duloxetine modulate nociceptive neurones in the medial prefrontal cortex, but not in the spinal cord of neuropathic rats

BACKGROUND

The noradrenergic system contributes to pain modulation, but the roles of its specific adrenoceptors are still being defined. We have identified a novel, potent (rat EC50  = 4.3 nM) and selective α2B receptor agonist, A-1262543, to further explore this adrenoceptor subtype's contribution to pathological nociception.

METHODS

Systemic administration of A-1262543 (1-10 mg/kg, intraperitoneal) dose-dependently attenuated mechanical allodynia in animals with a spinal nerve ligation injury. To further explore its mechanism of action, the activity of nociceptive neurones in the spinal cord and medial prefrontal cortex (mPFC) were examined after injection of 3 mg/kg of A-1262543 (intravenous, i.v.). These effects were compared with duloxetine (3 mg/kg, i.v.), a dual noradrenaline (NA) and serotonin (5-HT) reuptake inhibitor.

RESULTS

Systemic administration of A-1262543 or duloxetine did not alter the spontaneous or evoked firing of spinal wide dynamic range and nociceptive-specific neurones in the neuropathic rats, indicating that neither compound engaged spinal, peripheral or descending pathways. In contrast to the lack of effect on spinal neurones, both A-1262543 and duloxetine reduced the evoked and spontaneous firing of 'pain-responsive' (PR) neurones in the mPFC. Duloxetine, but not A-1262543, also inhibited the firing of pain non-responsive (nPR) neurones in the mPFC probably reflecting duloxetine's contribution to modulating non-pain endpoints.

CONCLUSIONS

These data highlight that activation of the α2B adrenoceptor as well as inhibiting NA and 5-HT reuptake can result in modulating the ascending nociceptive system, and in particular, dampening the firing of PR neurones in the mPFC.

Duloxetine treatment for women with premenstrual dysphoric disorder: a single-blind trial

Premenstrual dysphoric disorder (PMDD) affects 3-8% of women of reproductive age and is characterized by severe mood symptoms that cause important functional impairment. Serotonergic antidepressants appear to be an effective treatment for this disorder. The purpose of this study was to collect evidence on the efficacy and tolerability of duloxetine, a dual reuptake inhibitor of serotonin and norepinephrine, in the treatment of PMDD. We conducted a pilot, single-blind, non-controlled, fixed-dose trial. After two cycles for diagnosis confirmation, including a single-blind placebo cycle, 20 women with PMDD were treated continuously for three menstrual cycles with 60 mg/d duloxetine. The primary measure of the efficacy of treatment with duloxetine was the significant reduction in premenstrual symptoms demonstrated by the comparison between the mean Daily Record of Severity of Problems (DRSP) scores at baseline to endpoint (p=0.0002). Statistically significant symptom reduction was observed in the first treatment cycle and throughout all the treatment phase. Clinical response, defined as a reduction 50% of baseline premenstrual symptoms, occurred in 65% of subjects (intention-to-treat population). Significant improvements were demonstrated by secondary measures, including reduction in self-rated functional impairment (p=0.01) and improvement in quality of life (p=0.04). The main side-effects associated with duloxetine were dry mouth, nausea, drowsiness, insomnia, decreased appetite, decreased libido, and sweating. Duloxetine was effective and generally well tolerated in the treatment of PMDD. Further large-scale, double-blind, placebo-controlled studies are needed to evaluate duloxetine as an additional treatment strategy for the management of PMDD.

Neurotransmitter transporters and their impact on the development of psychopharmacology

The synaptic actions of most neurotransmitters are inactivated by reuptake into the nerve terminals from which they are released, or by uptake into adjacent cells. A family of more than 20 transporter proteins is involved. In addition to the plasma membrane transporters, vesicular transporters in the membranes of neurotransmitter storage vesicles are responsible for maintaining vesicle stores and facilitating exocytotic neurotransmitter release. The cell membrane monoamine transporters are important targets for CNS drugs. The transporters for noradrenaline and serotonin are key targets for antidepressant drugs. Both noradrenaline-selective and serotonin-selective reuptake inhibitors are effective against major depression and a range of other psychiatric illnesses. As the newer drugs are safer in overdose than the first-generation tricyclic antidepressants, their use has greatly expanded. The dopamine transporter (DAT) is a key target for amphetamine and methylphenidate, used in the treatment of attention deficit hyperactivity disorder. Psychostimulant drugs of abuse (amphetamines and cocaine) also target DAT. The amino-acid neurotransmitters are inactivated by other families of neurotransmitter transporters, mainly located on astrocytes and other non-neural cells. Although there are many different transporters involved (four for GABA; two for glycine/D-serine; five for L-glutamate), pharmacology is less well developed in this area. So far, only one new amino-acid transporter-related drug has become available: the GABA uptake inhibitor tiagabine as a novel antiepileptic agent.

Rational multidrug therapy in the treatment of neuropathic pain

Multidrug therapy (MDT) has been widely accepted and used as a standard of practice in most areas of medical practice, including neuropathic pain. Because neuropathic pain is a new field of medical science and practice, standards for its treatment including MDT are still evolving. In this article, we present rationale and principals for the MDT of neuropathic pain based on our best understandings of the underlying mechanisms of the disease processes and the actions of drugs, the goal being to maximize benefits and minimize adverse effects. MDT for neuropathic pain is based on a comprehensive clinical neuropathic pain assessment and ongoing monitoring of the drug therapy's efficacy and adverse effects, administering one drug at the time.

Desvenlafaxine succinate: A new serotonin and norepinephrine reuptake inhibitor

The purpose of this study was to characterize a new chemical entity, desvenlafaxine succinate (DVS). DVS is a novel salt form of the isolated major active metabolite of venlafaxine. Competitive radioligand binding assays were performed using cells expressing either the human serotonin (5-HT) transporter (hSERT) or norepinephrine (NE) transporter (hNET) with K(i) values for DVS of 40.2 +/- 1.6 and 558.4 +/- 121.6 nM, respectively. DVS showed weak binding affinity (62% inhibition at 100 microM) at the human dopamine (DA) transporter. Inhibition of [3H]5-HT or [3H]NE uptake by DVS for the hSERT or hNET produced IC50 values of 47.3 +/- 19.4 and 531.3 +/- 113.0 nM, respectively. DVS (10 microM), examined at a large number of nontransporter targets, showed no significant activity. DVS (30 mg/kg orally) rapidly penetrated the male rat brain and hypothalamus. DVS (30 mg/kg orally) significantly increased extracellular NE levels compared with baseline in the male rat hypothalamus but had no effect on DA levels using microdialysis. To mimic chronic selective serotonin reuptake inhibitor treatment and to block the inhibitory 5-HT(1A) autoreceptors, a 5-HT(1A) antagonist, N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclo hexanecarboxamide maleate salt (WAY-100635) (0.3 mg/kg s.c.), was administered with DVS (30 mg/kg orally). 5-HT increased 78% compared with baseline with no additional increase in NE or DA levels. In conclusion, DVS is a new 5-HT and NE reuptake inhibitor in vitro and in vivo that demonstrates good brain-to-plasma ratios, suggesting utility in a variety of central nervous system-related disorders.

Depression, pain, and somatoform disorders

PURPOSE OF REVIEW

The frequent co-occurrence of depression and somatic symptoms poses a continuing challenge to clinicians, researchers and experts involved in drawing up classifications. In this review we present recently published literature on aspects of epidemiology, classification and treatment in this important overlap area.

RECENT FINDINGS

From the multitude of papers published annually on the co-occurrence of different pain conditions and depression, temporomandibular dysfunction stands out this year by sheer quantity; it can be seen as a model case of the necessity for differentiated high-quality assessments on the biological as well as the psychosocial level. There is a general move to separate utility of diagnostic classifications from their validity, and this strengthens classificatory approaches that help to view the regular overlap of depression, pain and other somatic symptoms as the rule rather than the exception. The incorporation of cognitive variables like causal attributions should help to distinguish clinically relevant subtypes among overlap cases. The classificatory future of the category of 'somatoform disorders' is somewhat in doubt, but reforms seem to be more productive than abolishment. Psychopharmacology provides rather intense recent coverage of the overlap field, with newer dual serotonergic-noradrenergic reuptake inhibitors offering some promise.

SUMMARY

Treating the overlap of depression, pain and other somatic symptoms as the rule rather than the exception is necessary for adequate aetiological research as well as for diagnosis and treatment, with one-dimensional classificatory and treatment approaches almost certainly being insufficient.

Glutamatergic hypothesis of schizophrenia: involvement of Na+/K+-dependent glutamate transport

Hypothetical model based on deficient glutamatergic neurotransmission caused by hyperactive glutamate transport in astrocytes surrounding excitatory synapses in the prefrontal cortex is examined in relation to the aetiology of schizophrenia. The model is consistent with actions of neuroleptics, such as clozapine, in animal experiments and it is strongly supported by recent findings of increased expression of glutamate transporter GLT in prefrontal cortex of patients with schizophrenia. It is proposed that mechanisms regulating glutamate transport be investigated as potential targets for novel classes of neuroactive compounds with neuroleptic characteristics. Development of new efficient techniques designed specifically for the purpose of studying rapid activity-dependent translocation of glutamate transporters and associated molecules such as Na+, K+-ATPase is essential and should be encouraged.