Agomelatine in the treatment of major depressive disorder: an assessment of benefits and risks

The role of the methoxy group in approved drugs

The methoxy substituent is prevalent in natural products and, consequently, is present in many natural product-derived drugs. It has also been installed in modern drug molecules with no remnant of natural product features because medicinal chemists have been taking advantage of the benefits that this small functional group can bestow on ligand-target binding, physicochemical properties, and ADME parameters. Herein, over 230 methoxy-containing small-molecule drugs, as well as several fluoromethoxy-containing drugs, are presented from the vantage point of the methoxy group. Biochemical mechanisms of action, medicinal chemistry SAR studies, and numerous X-ray cocrystal structures are analyzed to identify the precise role of the methoxy group for many of the drugs and drug classes. Although the methoxy substituent can be considered as the hybridization of a hydroxy and a methyl group, the combination of these functionalities often results in unique effects that can amount to more than the sum of the individual parts.

Intranasal administration of sertraline ensures sustained brain delivery and antidepressant effect in a mouse model of depression

The pursuit of more potent and efficacious antidepressant therapies is of utmost significance. Herein, the intranasal (IN) route was investigated for sertraline brain delivery, encompassing a comparative pharmacokinetic study after a single-dose administration to mice by IN, intravenous (IV) (4.87 mg/kg) and oral (10 mg/kg) routes, and an efficacy/toxicity study to explore the therapeutic effect in mice subjected to the unpredictable chronic mild stress (UCMS) protocol. Neurotransmitters and melatonin were quantified in prefrontal cortex and plasma, respectively. A different drug biodistribution behavior was unveiled for a CNS-acting drug administered by means of the IN route. For the first time, IN administration of sertraline exhibited heightened systemic exposure (bioavailability = 166 %), and a sustained drug release into the brain, in opposition to IV and oral routes, avoiding drug fluctuation. The lower lung exposition (given by normalized area under the curve) observed after IN instillation envisions the reduction of sertraline pulmonary side effects and similarly other peripheral side effects. IN sertraline treatment displayed significant efficacy in ameliorating anhedonia after one week of administration while the 14-day IN treatment regimen translated into decreased immobility time and increased swimming time in the forced swimming test, suggesting an improvement of the depressive-like behavior displayed by the animal depressive-model. Remarkably, these effects were absent with oral sertraline, despite the higher used dose. Noteworthy neurotransmitter alterations were observed, with IN sertraline markedly reducing adrenaline in the prefrontal cortex, while serotonin and melatonin increased following both administration routes. With its sustained brain delivery and serotonin- and melatonin-enhancing potential, the innovative strategy of IN sertraline holds the potential not only to effectively address depressive symptoms but also to mitigate challenges inherent to classic treatments.

Agomelatine: A Potential Multitarget Compound for Neurodevelopmental Disorders

Agomelatine (AGM) is one of the latest atypical antidepressants, prescribed exclusively for the treatment of depression in adults. AGM belongs to the pharmaceutical class of melatonin agonist and selective serotonin antagonist ("MASS"), as it acts both as a selective agonist of melatonin receptors MT1 and MT2, and as a selective antagonist of 5-HT2C/5-HT2B receptors. AGM is involved in the resynchronization of interrupted circadian rhythms, with beneficial effects on sleep patterns, while antagonism on serotonin receptors increases the availability of norepinephrine and dopamine in the prefrontal cortex, with an antidepressant and nootropic effect. The use of AGM in the pediatric population is limited by the scarcity of data. In addition, few studies and case reports have been published on the use of AGM in patients with attention deficit and hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Considering this evidence, the purpose of this review is to report the potential role of AGM in neurological developmental disorders. AGM would increase the expression of the cytoskeleton-associated protein (ARC) in the prefrontal cortex, with optimization of learning, long-term memory consolidation, and improved survival of neurons. Another important feature of AGM is the ability to modulate glutamatergic neurotransmission in regions associated with mood and cognition. With its synergistic activity a melatoninergic agonist and an antagonist of 5-HT2C, AGM acts as an antidepressant, psychostimulant, and promoter of neuronal plasticity, regulating cognitive symptoms, resynchronizing circadian rhythms in patients with autism, ADHD, anxiety, and depression. Given its good tolerability and good compliance, it could potentially be administered to adolescents and children.

The Relationships Among Metal Homeostasis, Mitochondria, and Locus Coeruleus in Psychiatric and Neurodegenerative Disorders: Potential Pathogenetic Mechanism and Therapeutic Implications

While alterations in the locus coeruleus-noradrenergic system are present during early stages of neuropsychiatric disorders, it is unclear what causes these changes and how they contribute to other pathologies in these conditions. Data suggest that the onset of major depressive disorder and schizophrenia is associated with metal dyshomeostasis that causes glial cell mitochondrial dysfunction and hyperactivation in the locus coeruleus. The effect of the overactive locus coeruleus on the hippocampus, amygdala, thalamus, and prefrontal cortex can be responsible for some of the psychiatric symptoms. Although locus coeruleus overactivation may diminish over time, neuroinflammation-induced alterations are presumably ongoing due to continued metal dyshomeostasis and mitochondrial dysfunction. In early Alzheimer's and Parkinson's diseases, metal dyshomeostasis and mitochondrial dysfunction likely induce locus coeruleus hyperactivation, pathological tau or α-synuclein formation, and neurodegeneration, while reduction of glymphatic and cerebrospinal fluid flow might be responsible for β-amyloid aggregation in the olfactory regions before the onset of dementia. It is possible that the overactive noradrenergic system stimulates the apoptosis signaling pathway and pathogenic protein formation, leading to further pathological changes which can occur in the presence or absence of locus coeruleus hypoactivation. Data are presented in this review indicating that although locus coeruleus hyperactivation is involved in pathological changes at prodromal and early stages of these neuropsychiatric disorders, metal dyshomeostasis and mitochondrial dysfunction are critical factors in maintaining ongoing neuropathology throughout the course of these conditions. The proposed mechanistic model includes multiple pharmacological sites that may be targeted for the treatment of neuropsychiatric disorders commonly.

Pathophysiology and Current Drug Treatments for Post-Stroke Depression: A Review

Post-stroke depression (PSD) is a biopsychosocial disorder that affects individuals who have suffered a stroke at any point. PSD has a 20 to 60 percent reported prevalence among stroke survivors. Its effects are usually adverse, can lead to disability, and may increase mortality if not managed or treated early. PSD is linked to several other medical conditions, including anxiety, hyper-locomotor activity, and poor functional recovery. Despite significant awareness of its adverse impacts, understanding the pathogenesis of PSD has proved challenging. The exact pathophysiology of PSD is unknown, yet its complexity has been definitively shown, involving mechanisms such as dysfunction of monoamine, the glutamatergic systems, the gut-brain axis, and neuroinflammation. The current effectiveness of PSD treatment is about 30-40 percent of all cases. In this review, we examined different pathophysiological mechanisms and current pharmacological and non-pharmacological approaches for the treatment of PSD.

Agomelatine decreases cocaine-induced locomotor sensitisation and dopamine release in rats

BACKGROUND

Agomelatine is a melatoninergic antidepressant approved to treat the major depressive disorder. Agomelatine exerts its behavioural, pharmacological, and physiological effects through the activation of MT₁ and MT₂ melatonin receptors and the blockade of 5-HT_2B and 5-HT_2C serotonin receptors. Some studies have reported that the activation of the MT₁ and MT₂ melatonin receptors decreased cocaine-induced locomotor activity and cocaine self-administration. These findings from another study showed that agomelatine decreased alcohol consumption. This study aimed to evaluate the effects of agomelatine administration on cocaine-induced behavioural (cocaine-induced locomotor activity and cocaine-induced locomotor sensitisation) and neurochemical (dopamine levels) effects.

METHODS

Male Wistar rats (250-280 g) received cocaine (10 mg/kg) during the induction and expression of locomotor sensitisation. Agomelatine (10 mg/kg) was administered 30 minutes before cocaine. After each treatment, locomotor activity was recorded for 30 minutes. Dopamine levels were determined in the ventral striatum, the prefrontal cortex (PFC), and the ventral tegmental area (VTA) by high-performance liquid chromatographic (HPLC) in animals treated with agomelatine and cocaine. Luzindole (30 mg/kg) was administered to block the agomelatine effect.

RESULTS

In this study, we found that agomelatine decreased cocaine-induced locomotor activity and the induction and expression of locomotor sensitisation. In addition, agomelatine decreased cocaine-induced dopamine levels. Luzindole blocked the agomelatine-induced decrease in the expression of locomotor sensitisation in rats.

CONCLUSION

Our results suggest (1) that agomelatine showed efficacy in decreasing cocaine psychostimulant effects and (2) that agomelatine can be a useful therapeutic agent to reduce cocaine abuse.

The trilateral interactions between mammalian target of rapamycin (mTOR) signaling, the circadian clock, and psychiatric disorders: an emerging model

Circadian (~24 h) rhythms in physiology and behavior are evolutionarily conserved and found in almost all living organisms. The rhythms are endogenously driven by daily oscillatory activities of so-called "clock genes/proteins", which are widely distributed throughout the mammalian brain. Mammalian (mechanistic) target of rapamycin (mTOR) signaling is a fundamental intracellular signal transduction cascade that controls important neuronal processes including neurodevelopment, synaptic plasticity, metabolism, and aging. Dysregulation of the mTOR pathway is associated with psychiatric disorders including autism spectrum disorders (ASD) and mood disorders (MD), in which patients often exhibit disrupted daily physiological rhythms and abnormal circadian gene expression in the brain. Recent work has found that the activities of mTOR signaling are temporally controlled by the circadian clock and exhibit robust circadian oscillations in multiple systems. In the meantime, mTOR signaling regulates fundamental properties of the central and peripheral circadian clocks, including period length, entrainment, and synchronization. Whereas the underlying mechanisms remain to be fully elucidated, increasing clinical and preclinical evidence support significant crosstalk between mTOR signaling, the circadian clock, and psychiatric disorders. Here, we review recent progress in understanding the trilateral interactions and propose an "interaction triangle" model between mTOR signaling, the circadian clock, and psychiatric disorders (focusing on ASD and MD).

CYP1A2 polymorphism may contribute to agomelatine-induced acute liver injury: Case report and review of the literature

RATIONALE

Liver function monitoring is recommended when agomelatine is prescribed, although liver enzymes are not considered predictive biomarkers. Most patients present with acute liver injury, with only a few presenting with levels of liver enzymes that are over 30 times the upper limit of normal. The patient-specific risk factors that are associated with liver injury remain unclear. Thus, this report provides new insights into the mechanism of agomelatine-induced acute hepatocellular injury based on cytochrome P450 family 1 subfamily A member 2 (CYP1A2) polymorphism.

PATIENT CONCERNS

We present a case of acute hepatocellular injury in a 75-year-old man who was taking agomelatine at a dose of 50 mg/qn. All hepatitis virus test results were negative. No history of liver disease was observed. As CYP1A2 is the main metabolic enzyme of agomelatine, CYP1A2 AA (rs762551) genetic polymorphism was analyzed.

DIAGNOSIS

The patient's transaminases level exceeded the critical value on day 72 after starting oral agomelatine.

INTERVENTIONS

The patient received intravenous magnesium isoglycyrrhizinate, a liver cell-protecting agent, followed by the withdrawal of agomelatine.

OUTCOMES

There was an improvement in the levels of the liver enzymes and no subsequent organ dysfunction was observed.

LESSONS

Here, we report a case of acute hepatocellular injury characterized by a very high aspartate aminotransferase level. Periodic liver function testing throughout the treatment period can help in the rapid and appropriate diagnosis of acute liver injury, particularly in the absence of typical clinical manifestations. Agomelatine hepatic toxicity might be related to an idiosyncratic metabolic reaction that depends on individual patient differences. As it is the main metabolic enzyme of agomelatine, CYP1A2 genetic polymorphism may contribute to liver injury by affecting its metabolites.

Comparison of the efficacy of electroconvulsive therapy (ECT) plus agomelatine to ECT plus placebo in treatment-resistant depression

OBJECTIVE

Electroconvulsive therapy (ECT) is commonly used to treat patients with treatment-resistant depression. We aimed to investigate whether combining an antidepressant agent with ECT might enhance therapeutic efficacy and prevent early relapse.

METHOD

During the acute ECT phase, patients (N = 97) with treatment-resistant depression were randomized to receive ECT plus agomelatine 50 mg/day (n = 48) or ECT plus placebo (n = 49). Symptom severity measures, including the 17-item Hamilton Depression Rating Scale (HAMD-17) and other scales, functional impairment, quality of life, neuropsychological tests, adverse events and attitudes toward ECT, were assessed regularly. Remission was defined as a HAMD-17 score ≤7. If patients achieved post-ECT remission, they were prescribed agomelatine 50 mg/day and participated in a 12-week follow-up trial. HAMD-17 was rated at 4-week intervals. Relapse was defined as a HAMD-17 score ≥14, or rehospitalization for a psychiatric reason.

RESULTS

The two treatment groups were comparable at (i) baseline variables; (ii) score changes in all symptom measures, functional impairment, quality of life, and neuropsychological tests; (iii) frequency of adverse events and attitudes toward ECT; and (iv) post-ECT response/remission rates. There were no statistically significant differences following ECT in relapse rates and time to relapse between these two groups.

CONCLUSION

Adding agomelatine to ECT yielded comparable response/remission rates to ECT without agomelatine in the acute ECT phase. Starting agomelatine in combination with ECT did not seem to be more efficacious in preventing relapse than starting agomelatine after the acute ECT course. More research is needed to guide clinical recommendations.

What combinations of agomelatine with other antidepressants could be successful during the treatment of major depressive disorder or anxiety disorders in clinical practice?

Even with many antidepressant and anxiolytic drugs available on the market, there are still patients who do not respond well to the standard first or second line treatments for affective or anxiety disorders. The antidepressant agomelatine has been used in Europe for several years. Agomelatine, an agonist at melatonin receptors and an antagonist at serotonin receptors, can be particularly useful in patients suffering from a major depressive disorder associated with insomnia. Some clinical data have shown a limited effect for agomelatine in a subset of patients with major depression. A number of case reports published in 2011-2016 describe the effect of agomelatine in combination with an established antidepressant, such as escitalopram, venlafaxine, duloxetine, moclobemide or bupropion. A successful combination of agomelatine was reported after adjunctive use of agomelatine combined with clomipramine, escitalopram, and venlafaxine in patients with major depression or obsessive-compulsive disorder. Moreover, bupropion or moclobemide augmentation with agomelatine in patients with major depressive disorder led to a significant improvement. Other supportive data have been published, such as analysis of the VIVALDI study, although it should be noted that the study was supported by the manufacturer of agomelatine. In this study, agomelatine in combination with other antidepressants was shown to be effective and well tolerated in practice, although the most effective antidepressant treatment in the study consisted of agomelatine alone and not in combination with other antidepressants. There have also been two published case reports about the concomitant use of duloxetine and agomelatine which were not efficacious. The positive results of agomelatine augmentation with other antidepressants should be confirmed through randomized, double-blind clinical trials.

Psychopharmakotherapie bei Ein- und Durchschlafstörungen im Kindes- und Jugendalter: Eine Übersicht

Zusammenfassung. Ein- und Durchschlafstörungen sind mit einer Prävalenz von etwa 20 % eine relevante Symptomatik im Kindes- und Jugendalter. Aufgrund des mit Insomnien oftmals verbundenen verminderten psychosozialen Funktionsniveaus und des sich einstellenden Leidensdrucks ist eine suffiziente Behandlung notwendig. Zeigen sich Maßnahmen wie eine angemessene Schlafhygiene und andere nichtmedikamentöse Therapieansätze als nicht ausreichend, wird oftmals eine pharmakotherapeutische Behandlung in Betracht gezogen. Die vorliegende Arbeit bietet eine Literaturübersicht zum Einsatz verschiedener Substanzklassen in hypnotischer Indikation. Der Einsatz von Melatonin bei Kindern und Jugendlichen mit Autismus-Spektrum-Störungen ist zwischenzeitlich gut untersucht und ist mit einem positiven Effekt auf den Schlaf bei dieser Patientengruppe assoziiert. Hinsichtlich der Wirksamkeit und Verträglichkeit anderer Wirkstoffe bei primären Insomnien bzw. Schlafstörungen im Kontext anderer psychiatrischer Erkrankungen bei Minderjährigen besteht bislang eine geringe Evidenz. Daher sind zunächst nichtmedikamentöse Behandlungsstrategien vorzuziehen und eine Pharmakotherapie erst sekundär und nach kritischer Abwägung zu erwägen.

Parallel Changes in Mood and Melatonin Rhythm Following an Adjunctive Multimodal Chronobiological Intervention With Agomelatine in People With Depression: A Proof of Concept Open Label Study

Background: Agomelatine is a melatonin agonist and 5HT antagonist developed for the treatment of major depressive disorder which also has some effects on the circadian system. Since circadian dysfunctions are thought to play a role in the pathophysiology of depression, some of the mechanism of action of this drug may relate to improvements in circadian rhythms. Objective: This proof of concept open-label study sought to determine if improvements in depressive symptoms following an adjunctive multimodal intervention including agomelatine intake are associated with the magnitude of circadian realignment. This was investigated in young people with depression, a subgroup known to have high rates of delayed circadian rhythms. Methods: Young people with depression received a psychoeducation session about sleep and circadian rhythms, were asked to progressively phase advance their wake up time, and completed an 8 weeks course of agomelatine (25-50 mg). Participants underwent semi-structured psychological assessments, ambulatory sleep-wake monitoring and measurement of melatonin circadian phase before and after the intervention. Results: Twenty-four young adults with depression (17-28 years old; 58% females) completed the study. After the intervention, depressive symptoms were significantly reduced [t ₍₂₃₎ = 6.9, p < 0.001] and, on average, the timing of dim light melatonin onset (DLMO) shifted 3.6 h earlier [t ₍₁₈₎ = 4.4, p < 0.001]. On average, sleep onset was phase shifted 28 min earlier [t ₍₁₉₎ = 2.1, p = 0.047] and total sleep time increased by 24 min [t ₍₁₉₎ = -2.6, p = 0.018]. There was no significant change in wake-up times. A strong correlation (r = 0.69, p = 0.001) was found between the relative improvements in depression severity and the degree of phase shift in DLMO. Conclusion: Although this needs to be replicated in larger randomized controlled trials, these findings suggest that the degree of antidepressant response to a multimodal intervention including psychoeducation and agomelatine intake may be associated with the degree of change in evening melatonin release in young people with depression. This offers promising avenues for targeted treatment based on the prior identification of objective individual characteristics.

Circadian Rhythm Disturbances in Mood Disorders: Insights into the Role of the Suprachiasmatic Nucleus

Circadian rhythm disturbances are a common symptom among individuals with mood disorders. The suprachiasmatic nucleus (SCN), in the ventral part of the anterior hypothalamus, orchestrates physiological and behavioral circadian rhythms. The SCN consists of self-sustaining oscillators and receives photic and nonphotic cues, which entrain the SCN to the external environment. In turn, through synaptic and hormonal mechanisms, the SCN can drive and synchronize circadian rhythms in extra-SCN brain regions and peripheral tissues. Thus, genetic or environmental perturbations of SCN rhythms could disrupt brain regions more closely related to mood regulation and cause mood disturbances. Here, we review clinical and preclinical studies that provide evidence both for and against a causal role for the SCN in mood disorders.

Drug repurposing may generate novel approaches to treating depression

Objectives

The breakthrough advancements in scientific medical research have greatly improved our understanding of the pathogenesis of depression, encouraging drug discoverers to take a shorter path than ever through drug repurposing to generate new antidepressant medications. In addition to reduced noradrenergic and serotonergic neurotransmission in the brain, other coincidence features such as glutamate neurotoxicity, inflammation and/or cerebrovascular insufficiency are implicated in the pathogenesis of major depressive disorder and late-life depression. This short review discusses the progress made in repurposing drugs for antidepressant actions.

Key findings

Drugs being repurposed as antidepressants act on novel drug targets, thereby treating resistant depression and improving remission rate. Drugs such as ketamine, dextromethorphan/quinidine and scopolamine are rapidly acting antidepressants targeting glutamate receptors. Nimodipine and quetiapine are efficient add-on therapy for late-life depression. Anti-inflammatory drugs, statins, insulin sensitizers, minocycline could remarkably contribute to treating refractory depression.

Summary

Drug repurposing represents an alternative approach to cope with major obstacles, including financial insufficiency and unavoidable long lag evaluation time, undermining the classical pathway of developing new hit compounds into clinically approved antidepressants.

Marine cyanobacteria-derived serotonin receptor 2C active fraction induces psychoactive behavioral effects in mice

CONTEXT

Marine cyanobacteria offer a robust resource for natural products drug discovery due to the secondary metabolites they produce.

OBJECTIVE

To identify novel cyanobacterial compounds that exhibit CNS psychoactive effects.

MATERIALS AND METHODS

Cyanobacteria were collected from Las Perlas Archipelago, Panama and subjected to dichloromethane/methanol extraction and fractionation by column chromatography before being screened for affinity against a panel of CNS targets. A 50:50 ethyl acetate:methanol fraction of one cyanobacterial extract (2064H) was subjected to HPLC and the major peak was isolated (2064H3). At a dose of 20 μg per animal, 2064H and 2064H3 were tested in mice using behavioral assays that included the forced swim, open field and formalin tests.

RESULTS

2064H was shown to bind to the serotonin 2C (5-HT_2C) receptor, a known target for depression and pain treatment. 2064H showed 59.6% inhibition of binding of [³H]-mesulergine with an IC₅₀ value of 179 ng/mL and did not show inhibition of binding greater than 45% with any other receptors tested. Both 2064H and 2064H3 decreased immobility time in the first minute of the tail suspension test. 2064H increased time, distance and number of entries in the center region in the first half of the open field test. 2064H increased overall nocifensive behaviors in the formalin test.

DISCUSSION AND CONCLUSION

Overall, manipulating the 5-HT_2C receptor with these receptor-specific ligands derived from cyanobacteria altered pain, depression and anxiety-like behaviors, illustrating the importance of this receptor in affective behaviors. These results demonstrate the potential of cyanobacteria as a source for CNS active compounds.

Augmentation of antidepressant effects of venlafaxine by agomelatine in mice are independent of kynurenine pathway

Agomelatine is a novel antidepressant with agonistic actions at melatonergic (MT1 and MT2 receptors) and antagonistic actions at 5HT-2C receptors. Venlafaxine, a serotonin norepinephrine reuptake inhibitor, is a widely prescribed drug in depression. The present study evaluated the low dose combinations of venlafaxine and agomelatine in chronic forced swim test (chronic FST) and tail suspension test (TST) in mice. Further, the effect of above drugs and their combination was evaluated on serum pro-inflammatory cytokines and hippocampal indole amine 2, 3 dioxygenase (IDO) activity by calculating the ratios of kynurenine/tryptophan (KYN/TRP) and serotonin/tryptophan (5HT/TRP). Treatment of agomelatine (4 mg/kg, i.p.) in combination with venlafaxine (4 mg/kg, i.p.) for 3 weeks showed a significant augmenting effect on both swimming and immobility time in chronic FST and immobility time in TST as compared to animals treated with either drug alone. While venlafaxine (4 mg/kg) reversed the elevated serum levels of IL-1β and IL-6 found in chronically stressed mice, agomelatine (4 and 8 mg/kg) failed to show such a reversal. Agomelatine alone and in combination also failed to reverse the increased activity of IDO as observed by enhanced KYN/TRP and reduced 5HT/TRP seen in chronically stressed mice indicating that the augmented antidepressant effect of venlafaxine by agomelatine is not mediated by pro-inflammatory cytokine-induced activation of IDO and further, kynurenine pathway.

Clinical management of sleep disturbances in Alzheimer's disease: current and emerging strategies

Sleep and circadian disorders in Alzheimer's disease (AD) are more frequent than in the general population and appear early in the course of the disease. Quality of sleep and quality of life are parallel in these patients, and such disorders also represent a heavy burden for caregivers. Although alterations in melatonin and hypocretins (orexins) seem to play a key role in the origin of these disturbances, the etiology of these disorders is multifactorial, including many factors such as environment, behavior, treatments, and comorbidities, among others. A comprehensive evaluation of sleep in each patient is essential in the design of the treatment that includes nonpharmacological and pharmacological approaches. One particularly interesting point is the possibility of a role of sleep disorders in the pathogenesis of AD, raising the possibility that treating the sleep disorder may alter the course of the disease. In this review, we present an update on the role of sleep disorders in AD, the bidirectional influence of sleep problems and AD, and treatment options. Behavioral measures, bright light therapy (BLT), melatonin, and other drugs are likely well known and correctly managed by the physicians in charge of these patients. In spite of the multiple treatments used, evidence of efficacy is scarce and more randomized double-blind placebo-controlled studies are needed. Future directions for treatment are the establishment of BLT protocols and the development of drugs with new mechanisms of action, especially hypocretin receptor antagonists, melatonin receptor agonists, and molecules that modulate the circadian clock.

Activation of Melatonin Receptors Reduces Relapse-Like Alcohol Consumption

Melatonin is an endogenous synchronizer of biological rhythms and a modulator of physiological functions and behaviors of all mammals. Reduced levels of melatonin and a delay of its nocturnal peak concentration have been found in alcohol-dependent patients and rats. Here we investigated whether the melatonergic system is a novel target to treat alcohol addiction. Male Wistar rats were subjected to long-term voluntary alcohol consumption with repeated abstinence phases. Circadian drinking rhythmicity and patterns were registered with high temporal resolution by a drinkometer system and analyzed by Fourier analysis. We examined potential antirelapse effect of the novel antidepressant drug agomelatine. Given that agomelatine is a potent MT1 and MT2 receptor agonist and a 5-HT2C antagonist we also tested the effects of melatonin itself and the 5-HT2C antagonist SB242084. All drugs reduced relapse-like drinking. Agomelatine and melatonin administered at the end of the light phase led to very similar changes on all measures of the post-abstinence drinking behavior, suggesting that effects of agomelatine on relapse-like behavior are mostly driven by its melatonergic activity. Both drugs caused a clear phase advance in the diurnal drinking pattern when compared with the control vehicle-treated group and a reduced frequency of approaches to alcohol bottles. Melatonin given at the onset of the light phase had no effect on the circadian phase and very small effects on alcohol consumption. We conclude that targeting the melatonergic system in alcohol-dependent individuals can induce a circadian phase advance, which may restore normal sleep architecture and reduce relapse behavior.

Personalized medicine for pathological circadian dysfunctions

The recent approval of a therapeutic for a circadian disorder has increased interest in developing additional medicines for disorders characterized by circadian disruption. However, previous experience demonstrates that drug development for central nervous system (CNS) disorders has a high failure rate. Personalized medicine, or the approach to identifying the right treatment for the right patient, has recently become the standard for drug development in the oncology field. In addition to utilizing Companion Diagnostics (CDx) that identify specific genetic biomarkers to prescribe certain targeted therapies, patient profiling is regularly used to enrich for a responsive patient population during clinical trials, resulting in fewer patients required for statistical significance and a higher rate of success for demonstrating efficacy and hence receiving approval for the drug. This personalized medicine approach may be one mechanism that could reduce the high clinical trial failure rate in the development of CNS drugs. This review will discuss current circadian trials, the history of personalized medicine in oncology, lessons learned from a recently approved circadian therapeutic, and how personalized medicine can be tailored for use in future clinical trials for circadian disorders to ultimately lead to the approval of more therapeutics for patients suffering from circadian abnormalities.

Comparison of paroxetine and agomelatine in depressed type 2 diabetes mellitus patients: a double-blind, randomized, clinical trial

BACKGROUND

Comorbid depression/anxiety in type 2 diabetes mellitus (DM) patients is highly prevalent, affecting both diabetes control and quality of life. However, the best treating method for depression/anxiety in type 2 DM patients is still unclear. This study was conducted to compare the efficacy of paroxetine and agomelatine on depression/anxiety and metabolic control of type 2 DM patients.

METHODS

A total of 116 depressed, type 2 DM patients were recruited for 12 weeks treatment. Patients were randomly assigned to receive either paroxetine or agomelatine. Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scale were used to assess depression and anxiety, respectively. Hemoglobin A1c, fasting plasma glucose, and body mass index were assessed at baseline and at the end of the trial.

RESULTS

At the end of the trial, there were 34 (60.7%) responders and 22 (39.3%) remissions in paroxetine group; and 38 (63.3%) responders and 26 (43.3%) remissions in agomelatine group. Compared to paroxetine group, lower depression scores were observed in agomelatine group. Fasting plasma glucose and body mass index were not significantly different after 12 weeks treatment between the two groups, but agomelatine group had a significantly lower final hemoglobin A1c level compared to paroxetine group. The two antidepressants had comparable acceptability.

CONCLUSION

These results showed that compared to paroxetine, agomelatine might have some advantages in treating symptoms of depression/anxiety and glycemic control in depressed type 2 DM patients. The clinical applicability of agomelatine shows greater promise and should be explored further. Limited by the relatively small samples, future studies are needed to verify and support our findings.