Hepatotoxicity related to agomelatine and other new antidepressants: a case/noncase approach with information from the Portuguese, French, Spanish, and Italian pharmacovigilance systems

Acute toxicity and genotoxicity studies on new melatonergic antidepressant GW117

GW117, a novel derivate compound of agomelatine that acts as both a 5-HT2C receptor antagonist and a MT1/MT2 receptor agonist, likely underlines the potent antidepressant action with less hepatotoxicity than agomelatine. We evaluated the acute toxicity of GW117, and the genotoxicity of GW117 using bacterial reverse mutation test, mammalian chromosomal aberration test in Chinese hamster lung cells (CHL) and mouse bone marrow micronucleus test. The acute toxicity test results showed that maximum tolerated dose (MTD) of GW117 was 2000 mg/kg, under which mean C_max and AUC_0→t was 10,782 ng/mL and 81,046 ng/mL × h, respectively. The result of bacterial reverse mutation test showed that the number of bacterial colonies in each dose group of GW117 did not increase significantly compared with that in the solvent control group with or without S9 metabolic activation system. In vitro chromosome aberration test of CHL cells, the chromosome aberration rate of each dose group of GW117 did not increase with or without S9 metabolic activation system. In mouse micronucleus test, the highest dose was 2000 mg/kg, the micronucleus rate did not increase significantly. Under the conditions of this study, the MTD of a single GW117 administration was 2000 mg/kg, there was no genotoxicity effect of GW117.

Evaluation of the antidepressive property of β-hydroxybutyrate in mice

β-hydroxybutyrate, a ketone body metabolite, has been shown to suppress depression-like behavior in rodents. In this study, we examined its antidepressive property in acute and chronic administration modes in mice by using forced swim test and tail suspension test. Results showed that the decrease effect of β-hydroxybutyrate (300 mg/kg) on immobility time in the tail suspension test and forced swim test in stress-naive mice began to be significant at day 11. In a dose-dependent experiment, β-hydroxybutyrate treatment (11 days) showed significant antidepressant activities at the dose of 200 and 300 mg/kg. Unlike fluoxetine, β-hydroxybutyrate treatment (300 mg/kg) showed no antidepressant activities in the acute (1 hour before the test) and three times administration mode within 24 hours (1, 5, and 24 hours before the test). But in a co-administration mode, β-hydroxybutyrate (100 mg/kg) -fluoxetine (2.5 mg/kg) co-administration exhibited an obvious antidepressant activity in the tail suspension test and forced swim test. Further analysis showed that the antidepressant effects of β-hydroxybutyrate and fluoxetine were not associated with the change in mouse locomotor activity. Furthermore, both chronic β-hydroxybutyrate treatment and β-hydroxybutyrate-fluoxetine co-treatment suppressed chronic unpredictable stress-induced increase in immobility time in the tail suspension test and forced swim test as well as chronic unpredictable stress-induced decrease in mouse body weight. Taken together, these results indicate that β-hydroxybutyrate (1) needs a relatively long time to show comparable behavioral activity to that of fluoxetine in assays that are sensitive to the behavioral effects of established antidepressant compounds and (2) can augment the antidepressant action of a sub-therapeutic dose of fluoxetine.

The Impact of Chronic Mild Stress and Agomelatine Treatment on the Expression Level and Methylation Status of Genes Involved in Tryptophan Catabolic Pathway in PBMCs and Brain Structures

Depression is the serious mental disorder. Previous studies suggest that the development mechanism of depression may be associated with disorders of the tryptophan catabolic pathway (TRYCAT). Thus, this study investigates the effect of agomelatine treatment on the expression and methylation status of genes involved in TRYCAT in the brain and blood of rats exposed to a chronic mild stress (CMS). Separate groups of rats were exposed to CMS for two or seven weeks; the second group received vehicle or agomelatine for five weeks. After completion of both stress conditions and treatment, the expression levels of messenger RNA (mRNA) and protein, as well as the methylation status of promoters, were measured in peripheral blood mononuclear cells (PBMCs) and in brain structures with the use of TaqMan Gene Expression Assay, Western blot, and methylation-sensitive high-resolution melting techniques. In PBMCs, Kmo mRNA expression increased in the group after CMS, while this effect was normalized by agomelatine therapy. In brain, KatI and KatII expression changed following CMS exposure. Moreover, CMS decreased the methylation status of the second Tdo2 promoter in the amygdala. Protein expression of Tph1, Tph2, Ido1, and KatII changed in the group after CMS and agomelatine administration, most prominently in the basal ganglia, cerebral cortex, hippocampus, and amygdala. The results indicate that CMS and agomelatine affect the mRNA and protein expression, as well as the methylation of promoters of genes involved in the tryptophan catabolic pathway.

Antidepressants and movement disorders: a postmarketing study in the world pharmacovigilance database

BACKGROUND

Antidepressants-induced movement disorders are rare and imperfectly known adverse drug reactions. The risk may differ between different antidepressants and antidepressants' classes. The objective of this study was to assess the putative association of each antidepressant and antidepressants' classes with movement disorders.

METHODS

Using VigiBase®, the WHO Pharmacovigilance database, disproportionality of movement disorders' reporting was assessed among adverse drug reactions related to any antidepressant, from January 1967 to February 2017, through a case/non-case design. The association between nine subtypes of movement disorders (akathisia, bruxism, dystonia, myoclonus, parkinsonism, restless legs syndrome, tardive dyskinesia, tics, tremor) and antidepressants was estimated through the calculation first of crude Reporting Odds Ratio (ROR), then adjusted ROR on four potential confounding factors: age, sex, drugs described as able to induce movement disorders, and drugs used to treat movement disorders.

RESULTS

Out of the 14,270,446 reports included in VigiBase®, 1,027,405 (7.2%) contained at least one antidepressant, among whom 29,253 (2.8%) reported movement disorders. The female/male sex ratio was 2.15 and the mean age 50.9 ± 18.0 years. We found a significant increased ROR for antidepressants in general for all subtypes of movement disorders, with the highest association with bruxism (ROR 10.37, 95% CI 9.62-11.17) and the lowest with tics (ROR 1.49, 95% CI 1.38-1.60). When comparing each of the classes of antidepressants with the others, a significant association was observed for all subtypes of movement disorders except restless legs syndrome with serotonin reuptake inhibitors (SRIs) only. Among antidepressants, mirtazapine, vortioxetine, amoxapine, phenelzine, tryptophan and fluvoxamine were associated with the highest level to movement disorders and citalopram, paroxetine, duloxetine and mirtazapine were the most frequently associated with movement disorders. An association was also found with eight other antidepressants.

CONCLUSIONS

A potential harmful association was found between movement disorders and use of the antidepressants mirtazapine, vortioxetine, amoxapine, phenelzine, tryptophan, fluvoxamine, citalopram, paroxetine, duloxetine, bupropion, clomipramine, escitalopram, fluoxetine, mianserin, sertraline, venlafaxine and vilazodone. Clinicians should beware of these adverse effects and monitor early warning signs carefully. However, this observational study must be interpreted as an exploratory analysis, and these results should be refined by future epidemiological studies.

Risk of Acute Liver Injury in Agomelatine and Other Antidepressant Users in Four European Countries: A Cohort and Nested Case-Control Study Using Automated Health Data Sources

BACKGROUND

Agomelatine is a melatonin receptor agonist and serotonin 5-HT2C receptor antagonist indicated for depression in adults. Hepatotoxic reactions like acute liver injury (ALI) are an identified risk in the European risk management plan for agomelatine. Hepatotoxic reactions have been reported for other antidepressants, but population studies quantifying these risks are scarce. Antidepressants are widely prescribed, and users often have risk factors for ALI (e.g. metabolic syndrome).

OBJECTIVE

The goal was to estimate the risk of ALI associated with agomelatine and other antidepressants (fluoxetine, paroxetine, sertraline, escitalopram, mirtazapine, venlafaxine, duloxetine, and amitriptyline) when compared with citalopram in routine clinical practice.

METHOD

A nested case-control study was conducted using data sources in Denmark, Germany, Spain, and Sweden (study period 2009-2014). Three ALI endpoints were defined using International Classification of Diseases (ICD) codes: primary (specific codes) and secondary (all codes) endpoints used only hospital discharge codes; the tertiary endpoint included both inpatient and outpatient settings (all codes). Validation of endpoints was implemented. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for current use were estimated for each data source and combined.

RESULTS

We evaluated 3,238,495 new antidepressant and 74,440 agomelatine users. For the primary endpoint, the OR for agomelatine versus citalopram was 0.48 (CI 0.13-1.71). Results were also < 1 when no exclusion criteria were applied (OR 0.37; CI 0.19-0.74), when all exclusion criteria except alcohol and drug abuse were applied (OR 0.47; CI 0.20-1.07), and for the secondary (OR 0.40; CI 0.05-3.11) and tertiary (OR 0.79; CI 0.50-1.25) endpoints. Regarding other antidepressants versus citalopram, most OR point estimates were also below one, although with varying widths of the 95% CIs. The result of the tertiary endpoint and the sensitivity analyses of the primary endpoint were the most precise.

CONCLUSION

In this study, using citalopram as a comparator, agomelatine was not associated with an increased risk of ALI hospitalisation. The results for agomelatine should be interpreted in the context of the European risk minimisation measures in place. Those measures may have induced selective prescribing and could explain the lower risk of ALI for agomelatine when compared with citalopram. Most other antidepressants evaluated had ORs suggesting a lower risk than citalopram, but additional studies are required to confirm or refute these results.

Oxymatrine ameliorates agomelatine-induced hepatocyte injury through promoting proteasome-mediated CHOP degradation

BACKGROUND

The novel antidepressant drug agomelatine has been observed to cause adverse effect of hepatotoxicity in clinical applications. This study was designed to explore protective agents and investigated the underlying mechanism on L02 cells.

METHOD

L02 cells were treated with agomelatine and oxymatrine (OMT) and cell apoptosis were analyzed through flow cytometric analysis, CCK-8 assay and TUNEL assay. In a separate experiment, the expressions of ER stress-related proteins were determined by western blot. In addition, MG132, chloroquine (CQ) and bafilomycinA1(BafA1) were used to investigate the potential pathway participating in CHOP degradation.

RESULTS

OMT significantly rescued agomelatine-induced hepatocyte apoptosis. Agomelatine treatment resulted in accumulation of CHOP protein in L02 cells, and this phenomenon could be significantly reduced by OMT, whereas abolished by MG132 treatment.

CONCLUSION

We have demonstrated for the first time that OMT ameliorates the hepatocyte toxicity induced by agomelatine through decreasing CHOP on protein level. The underlying mechanism was proved to involve the molecular events that OMT promotes CHOP degradation via proteasome pathway. Overall, these results suggest that using OMT in combination with agomelatine may provide a safety strategy for clinical depression treatment.

Effects of sulforaphane in the central nervous system

Sulforaphane (SFN) is an active component extracted from vegetables like cauliflower and broccoli. Activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling is a common mechanism for the anti-oxidative and anti-inflammatory activity of some herb-derived compounds, such as icariin and berberine. However, due to its peculiar ability in Nrf2 activation, SFN is recognized as an activator of Nrf2 and recommended as a supplementation for prevention and/or treatment of disorders like neoplasm and heart failure. In the central nervous system (CNS), the prophylactic and/or therapeutic effects of SFN have been revealed in recent years. For example, it has been reported to prevent the progression of Alzheimer's disease, Parkinson's disease, cerebral ischemia, Huntington's disease, multiple sclerosis, epilepsy, and psychiatric disorders via promotion of neurogenesis or inhibition of oxidative stress and neuroinflammation. SFN is also implicated in reversing cognition, learning, and memory impairment in rodents induced by scopolamine, lipopolysaccharide, okadaic acid, and diabetes. In models of neurotoxicity, SFN has been shown to suppress neurotoxicity induced by a wide range of toxic factors, such as hydrogen peroxide, prion protein, hyperammonemia, and methamphetamine. To date, no consolidated source of knowledge about the pharmacological effects of SFN in the CNS has been presented in the literature. In this review, we summarize and discuss the pharmacological effects of SFN as well as their possible mechanisms in prevention and/or therapy of disorders afflicting the CNS, aiming to get a further insight into how SFN affects the pathophysiological process of CNS disorders.

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.

Depressive disorders: Processes leading to neurogeneration and potential novel treatments

Mood disorders are wide spread with estimates that one in seven of the population are affected at some time in their life (Kessler et al., 2012). Many of those affected with severe depressive disorders have cognitive deficits which may progress to frank neurodegeneration. There are several peripheral markers shown by patients who have cognitive deficits that could represent causative factors and could potentially serve as guides to the prevention or even treatment of neurodegeneration. Circadian rhythm misalignment, immune dysfunction and oxidative stress are key pathologic processes implicated in neurodegeneration and cognitive dysfunction in depressive disorders. Novel treatments targeting these pathways may therefore potentially improve patient outcomes whereby the primary mechanism of action is outside of the monoaminergic system. Moreover, targeting immune dysfunction, oxidative stress and circadian rhythm misalignment (rather than primarily the monoaminergic system) may hold promise for truly disease modifying treatments that may prevent neurodegeneration rather than simply alleviating symptoms with no curative intent. Further research is required to more comprehensively understand the contributions of these pathways to the pathophysiology of depressive disorders to allow for disease modifying treatments to be discovered.

Drug-induced liver injury: Do we know everything?

Interest in drug-induced liver injury (DILI) has dramatically increased over the past decade, and it has become a hot topic for clinicians, academics, pharmaceutical companies and regulatory bodies. By investigating the current state of the art, the latest scientific findings, controversies, and guidelines, this review will attempt to answer the question: Do we know everything? Since the first descriptions of hepatotoxicity over 70 years ago, more than 1000 drugs have been identified to date, however, much of our knowledge of diagnostic and pathophysiologic principles remains unchanged. Clinically ranging from asymptomatic transaminitis and acute or chronic hepatitis, to acute liver failure, DILI remains a leading causes of emergent liver transplant. The consumption of unregulated herbal and dietary supplements has introduced new challenges in epidemiological assessment and clinician management. As such, numerous registries have been created, including the United States Drug-Induced Liver Injury Network, to further our understanding of all aspects of DILI. The launch of LiverTox and other online hepatotoxicity resources has increased our awareness of DILI. In 2013, the first guidelines for the diagnosis and management of DILI, were offered by the Practice Parameters Committee of the American College of Gastroenterology, and along with the identification of risk factors and predictors of injury, novel mechanisms of injury, refined causality assessment tools, and targeted treatment options have come to define the current state of the art, however, gaps in our knowledge still undoubtedly remain.

Psychotropic drugs and liver disease: A critical review of pharmacokinetics and liver toxicity

The liver is the organ by which the majority of substances are metabolized, including psychotropic drugs. There are several pharmacokinetic changes in end-stage liver disease that can interfere with the metabolization of psychotropic drugs. This fact is particularly true in drugs with extensive first-pass metabolism, highly protein bound drugs and drugs depending on phase I hepatic metabolic reactions. Psychopharmacological agents are also associated with a risk of hepatotoxicity. The evidence is insufficient for definite conclusions regarding the prevalence and severity of psychiatric drug-induced liver injury. High-risk psychotropics are not advised when there is pre-existing liver disease, and after starting a psychotropic agent in a patient with hepatic impairment, frequent liver function/lesion monitoring is advised. The authors carefully review the pharmacokinetic disturbances induced by end-stage liver disease and the potential of psychopharmacological agents for liver toxicity.

An original pharmacoepidemiological-pharmacodynamic method: application to antipsychotic-induced movement disorders

AIMS

Pharmacovigilance databases are usually used to detect new potential signals that are relevant for drug safety. They are seldom used for explanatory purposes, e.g. to understand the mechanisms of adverse drug reactions (ADRs). The aim of the present study was to combine pharmacovigilance and pharmacodynamic data to investigate the association between dopamine D2, serotonin 5HT2A, and muscarinic M1 receptor occupancy and the risks of antipsychotic drug (AP)-induced movement disorders.

METHODS

First, we performed a case-noncase analysis using spontaneous reports from the World Health Organization (WHO) Global Individual Case Safety Report (ICSR) database, VigiBase®. We thus measured the risk of reporting movement disorders compared with all other ADRs [expressed as a reporting odds ratio (ROR)] for APs. Second, we performed a linear regression analysis to explore the association between the estimated risk of reporting for individual drugs and their receptor occupancy properties, for D2, 5HT2A and M1 receptors.

RESULTS

Compared with second-generation APs, first-generation APs were found to be significantly more associated with the reporting of movement disorders in general but also with dystonia, Parkinsonism, akathisia and tardive dyskinesia, irrespective of gender. A significant inverse correlation was found between the ROR for movement disorders and the receptor occupancy of 5HT2A [P < 0.001; R²  = 0.51; slope = -0.014; 95% confidence interval (CI) (-0.029, 0.001)], M1 (P < 0.001; R²  = 0.56; slope = -0.014; 95% CI (-0.028, 0.001) but not D2 dopamine (P = 0.54; R²  = 0.02; slope = -0.003; 95% CI (-0.007, 0.001) receptors.

CONCLUSIONS

Using the example of AP-induced movement disorders, the present study underlines the value of the pharmacoepidemiological-pharmacodynamic method to explore ADR mechanisms in humans and real-life settings.

In vitro and in vivo evaluation of the mechanisms of citalopram-induced hepatotoxicity

Even though citalopram is commonly used in psychiatry, there are several reports on its toxic effects. So, the current study was designed to elucidate the mechanisms of cytotoxic effects of in vitro and in vivo citalopram treatment on liver and the following cytolethal events. For in vitro experiments, freshly isolated rat hepatocytes were exposed to citalopram along with/without various agents. To do in vivo studies liver function enzyme assays and histological examination were performed. In the in vitro experiments, citalopram (500 µM) exposure demonstrated cell death, a marked elevation in ROS formation, mitochondrial potential collapse, lysosomal membrane leakiness, glutathione (GSH) depletion and lipid peroxidation. In vivo biochemistry panel assays for liver enzymes function (AST, ALT and GGTP) and histological examination confirmed citalopram (20 mg/kg)-induced damage. citalopram-induced oxidative stress cytotoxicity markers were significantly prevented by antioxidants, ROS scavengers, MPT pore sealing agents, endocytosis inhibitors, ATP generators and CYP inhibitors. Either enzyme induction or GSH depletion were concomitant with augmented citalopram-induced damage both in vivo and in vitro which were considerably ameliorated with antioxidants and CYP inhibitors. In conclusion, it is suggested that citalopram hepatotoxicity might be a result of oxidative hazard leading to mitochondrial/lysosomal toxic connection and disorders in biochemical markers which were supported by histomorphological studies.

Agomelatine for Depression in Parkinson Disease: Additional Effect on Sleep and Motor Dysfunction

Depression and sleep disorders are among the most prevalent nonmotor symptoms of Parkinson disease (PD). Because agomelatine acts as a MT1 and MT2 agonist and as a 5HT2c antagonist, this study was designed to assess the efficacy of agomelatine in treating depressive symptoms in PD patients, and the potential changes both in sleep quality and motor symptoms. Depressed patients with PD were treated with agomelatine for 6 months, and they were evaluated with an array of scales. Completed nocturnal video-polysomnography was performed at baseline and week 12. The efficacy analysis population included 24 patients (12 men). The mean (SD) age was 75.2 (8.3) years. The mean (SD) daily dose of agomelatine was 25.00 (10.43) mg at 24 weeks. No changes in dopamine replacement therapy were made. There was a significant decrease in the 17-item Hamilton Depression Scale score over the course of the study (P < 0.0005). The Scales for Outcomes in Parkinson disease Sleep Questionnaire showed a statistically significant improvement over time in each of its subscales: nighttime sleep (P < 0.005), last month nighttime sleep (P < 0.0005), and daytime sleepiness (P < 0.0005). Surprisingly, changes over time in the motor subscale of Unified Parkinson Disease Rating Scale were statistically significant (P < 0.0005). Periodic limb movements and awakenings measured by polysomnography improved significantly (P < 0.005 and P < 0.05, respectively). We concluded that the use of agomelatine in PD depressed patients may have a considerable therapeutic potential because of its dual action for treating both symptoms of depression and disturbed sleep given its secondary beneficial effects regarding the reduction of extrapyramidal symptoms.

Safety and tolerability of vortioxetine (15 and 20 mg) in patients with major depressive disorder: results of an open-label, flexible-dose, 52-week extension study

Vortioxetine is approved for the treatment of adults with major depressive disorder. This open-label extension (OLE) study evaluated the safety and tolerability of vortioxetine in the long-term treatment of major depressive disorder patients, as well as evaluated its effectiveness using measures of depression, anxiety, and overall functioning. This was a 52-week, flexible-dose, OLE study in patients who completed one of three randomized, double-blind, placebo-controlled, 8-week vortioxetine trials. All patients were switched to 10 mg/day vortioxetine for week 1, then adjusted between 15 and 20 mg for the remainder of the study, but not downtitrated below 15 mg. Safety and tolerability were assessed on the basis of treatment-emergent adverse events (TEAEs), vital signs, laboratory values, physical examination, and the Columbia-Suicide Severity Rating Scale. Efficacy measures included the Montgomery-Åsberg Depression Rating Scale, the Hamilton Anxiety Scale, the Clinical Global Impression Scale-Severity of Illness, and the Sheehan Disability Scale. Of the 1075 patients enrolled, 1073 received at least one dose of vortioxetine and 538 (50.0%) completed the study. A total of 537 patients withdrew early, with 115 (10.7% of the original study population) withdrawing because of TEAEs. Long-term treatment with vortioxetine was well tolerated; the most common TEAEs (≥10%) were nausea and headache. Laboratory values, vital signs, and physical examinations revealed no trends of clinical concern. The mean Montgomery-Åsberg Depression Rating Scale total score was 19.9 at the start of the extension study and 9.0 after 52 weeks of treatment (observed cases). Similar improvements were observed with the Hamilton Anxiety Scale (Δ-4.2), the Clinical Global Impression Scale-Severity of Illness (Δ-1.2), and the Sheehan Disability Scale (Δ-4.7) total scores after 52 weeks of treatment (observed case). In this 52-week, flexible-dose OLE study, 15 and 20 mg vortioxetine were safe and well tolerated. After entry into this study, patients continued to show improvement in depression and anxiety symptoms, as well as overall functioning, throughout the treatment period.

Drug- and herb-induced liver injury: Progress, current challenges and emerging signals of post-marketing risk

Drug-induced liver injury (DILI) and herb-induced liver injury is a hot topic for clinicians, academia, drug companies and regulators, as shown by the steadily increasing number of publications in the past 15 years. This review will first provide clues for clinicians to suspect idiosyncratic (unpredictable) DILI and succeed in diagnosis. Causality assessment remains challenging and requires careful medical history as well as awareness of multifaceted aspects, especially for herbs. Drug discontinuation and therapy reconciliation remain the mainstay in patent’s management to minimize occurrence of acute liver failure. The second section will address novel agents associated with liver injury in 2014 (referred to as “signals”), especially in terms of clinical, research and drug development implications. Insights will be provided into recent trends by highlighting the contribution of different post-marketing data, especially registries and spontaneous reporting systems. This literature scrutiny suggests: (1) the importance of post-marketing databases as tools of clinical evidence to detect signals of DILI risk; and (2) the need for joining efforts in improving predictivity of pre-clinical assays, continuing post-marketing surveillance and design ad hoc post-authorization safety studies. In this context, ongoing European/United States research consortia and novel pharmaco-epidemiological tools (e.g., specialist prescription event monitoring) will support innovation in this field. Direct oral anticoagulants and herbal/dietary supplements appear as key research priorities.

A systematic review of agomelatine-induced liver injury

Agomelatine is an antidepressant with a unique mechanism of action. Since its marketing in 2009, concerns have been raised regarding its potential to induce liver injury. The authors therefore address the need to comprehensively evaluate the potential risk posed by agomelatine of inducing liver injury by reviewing data from published and unpublished clinical trials in both the pre- and postmarketing settings, as well as data from non-interventional studies, pharmacovigilance database reviews and one case report. Recommendations for clinicians are also provided.

In this review, agomelatine was found to be associated with higher rates of liver injury than both placebo and the four active comparator antidepressants used in the clinical trials for agomelatine, with rates as high as 4.6% for agomelatine compared to 2.1% for placebo, 1.4% for escitalopram, 0.6% for paroxetine, 0.4% for fluoxetine, and 0% for sertraline. The review also provides evidence for the existence of a positive relationship between agomelatine dose and liver injury. Furthermore, rates of liver injury were found to be lower in non-interventional studies. Findings from pharmacovigilance database reviews and one case report also highlight the risk of agomelatine-induced liver injury.

As agomelatine does pose a risk of liver injury, clinicians must carefully monitor liver function throughout treatment. However, agomelatine’s unique mechanism of action and favourable safety profile render it a valuable treatment option.

A quantitative analysis of agomelatine-induced liver injury is lacking in the literature and would be welcomed.

Hepatotoxicity associated with agomelatine and other antidepressants: Disproportionality analysis using pooled pharmacovigilance data from the Uppsala Monitoring Centre

Since its marketing approval, the attention to the hepatic side-effect profile of the antidepressant agomelatine (AGM) has gradually increased. Several cases of severe hepatotoxic adverse drug reactions (ADR) have been reported and the European Medicines Agency has released a safety warning regarding AGM-associated hepatotoxicity. However, there are insufficient data for an adequate safety assessment of AGM-related hepatotoxicity. Therefore, we performed a quantitative signal detection analysis using pharmacovigilance data from the Uppsala Monitoring Centre from the WHO that records ADR data from worldwide sources; we calculated reporting odds ratios (ROR) as measures for disproportionality within a case/non-case approach for AGM and several other antidepressants. AGM was statistically associated with an increased risk of hepatotoxicity (ROR 6.4 [95%CI 5.7-7.2]) as well as both positive controls: amineptine (ROR 38.4 [95%CI 33.8-43.6]) and nefazodone (ROR 3.2 [95%CI 3.0-3.5]). Following amineptine, AGM was associated with the second highest ROR, followed by tianeptine (ROR 4.4 [95%CI 3.6-5.3]), mianserin (ROR 3.6 [95%CI 3.3-3.9]), and nefazodone. These results support the hypothesis that AGM is associated with relevant hepatotoxicity. However, the used data and applied method do not allow a quantitative evaluation of hepatotoxicity or assessment of substance-specific differences regarding the extent of hepatotoxicity.

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

Agomelatine (AGM) was approved for the treatment of major depressive disorder (MDD) in adults by the European Medicines Agency (EMA) in February 2009. It is an analogue of melatonin and features a unique pharmacodynamic profile with agonism on both types of melatonergic receptors (MT1/MT2) and antagonism at serotonergic 5-HT2C receptors. There is, however, an ongoing debate regarding the efficacy and safety of this novel antidepressant agent, originally evoked by claims of a significant publication bias underlying the assessment of AGM being an effective antidepressant. Indeed, two recent comprehensive metaanalyses of published and unpublished clinical trials found evidence for a relevant publication bias. However, due to its statistically significant advantage over placebo based on the results of these metaanalyses AGM must be referred to as an effective antidepressant agent in the acute phase of MDD. However, the effect sizes of AGM in the treatment of MDD were evaluated as being small in comparison to other antidepressant agents. In addition, there is insufficient evidence for the efficacy of AGM in relapse prevention of MDD. Apart from efficacy issues, AGM appears to have the potential to exhibit severe hepatotoxicity (the EMA has identified AGM-associated “hepatotoxic reactions” as a new safety concern in September 2013) that is currently poorly understood. Considering these aspects, it seems inappropriate to evaluate AGM as an antidepressant agent of first choice. Nevertheless, its unique mechanism of action with particular sleep modulating effects may represent a specific treatment strategy for patients with particular characteristics; further studies with thorough characterization of patients are needed to test this hypothesis.

Faster, better, stronger: towards new antidepressant therapeutic strategies

Major depression is a highly prevalent disorder and is predicted to be the second leading cause of disease burden by 2020. Although many antidepressant drugs are currently available, they are far from optimal. Approximately 50% of patients do not respond to initial first line antidepressant treatment, while approximately one third fail to achieve remission following several pharmacological interventions. Furthermore, several weeks or months of treatment are often required before clinical improvement, if any, is reported. Moreover, most of the commonly used antidepressants have been primarily designed to increase synaptic availability of serotonin and/or noradrenaline and although they are of therapeutic benefit to many patients, it is clear that other therapeutic targets are required if we are going to improve the response and remission rates. It is clear that more effective, rapid-acting antidepressants with novel mechanisms of action are required. The purpose of this review is to outline the current strategies that are being taken in both preclinical and clinical settings for identifying superior antidepressant drugs. The realisation that ketamine has rapid antidepressant-like effects in treatment resistant patients has reenergised the field. Further, developing an understanding of the mechanisms underlying the rapid antidepressant effects in treatment-resistant patients by drugs such as ketamine may uncover novel therapeutic targets that can be exploited to meet the Olympian challenge of developing faster, better and stronger antidepressant drugs.