Escitalopram versus SNRI antidepressants in the acute treatment of major depressive disorder: integrative analysis of four double-blind, randomized clinical trials

Investigating the relationship between hippocampus/dentate gyrus volume and hypothalamus metabolism in participants with major depressive disorder

Reduced hippocampal volume occurs in major depressive disorder (MDD), potentially due to elevated glucocorticoids from an overactivated hypothalamus-pituitary-adrenal (HPA) axis. To examine this in humans, hippocampal volume and hypothalamus (HPA axis) metabolism was quantified in participants with MDD before and after antidepressant treatment. 65 participants (n = 24 males, n = 41 females) with MDD were treated in a double-blind, randomized clinical trial of escitalopram. Participants received simultaneous positron emission tomography (PET)/magnetic resonance imaging (MRI) before and after treatment. Linear mixed models examined the relationship between hippocampus/dentate gyrus volume and hypothalamus metabolism. Chi-squared tests and multivariable logistic regression examined the association between hippocampus/dentate gyrus volume change direction and hypothalamus activity change direction with treatment. Multiple linear regression compared these changes between remitter and non-remitter groups. Covariates included age, sex, and treatment type. No significant linear association was found between hippocampus/dentate gyrus volume and hypothalamus metabolism. 62% (38 of 61) of participants experienced a decrease in hypothalamus metabolism, 43% (27 of 63) of participants demonstrated an increase in hippocampus size (51% [32 of 63] for the dentate gyrus) following treatment. No significant association was found between change in hypothalamus activity and change in hippocampus/dentate gyrus volume, and this association did not vary by sex, medication, or remission status. As this multimodal study, in a cohort of participants on standardized treatment, did not find an association between hypothalamus metabolism and hippocampal volume, it supports a more complex pathway between hippocampus neurogenesis and hypothalamus metabolism changes in response to treatment.

Increasing escitalopram dose is associated with fewer discontinuations than switch or combination approaches in patients initially on escitalopram 10mg

Purpose

To examine the relationship between different intervention approaches and subsequent real-life outcomes in patients changing treatment from escitalopram 10mg.

Method

This was a retrospective cohort study of patients starting antidepressant treatment between 2002 and 2004. Data were extracted from a US health-insurance reimbursement claims database. Eligible patients started escitalopram 10mg and changed within 3 months to: escitalopram ≥20mg; another antidepressant; or a combination of escitalopram with another antidepressant. Medication persistence and healthcare costs over 3 months were compared between the treatment groups.

Results

Overall, 37,791 patients started escitalopram 10mg. Of the 12,830 patients (34%) who changed treatment, 56% increased escitalopram dose, 26% switched antidepressant and 18% combined escitalopram with another antidepressant. Patients in the switch and combination groups had significantly higher rates of non-persistence (56% and 91%, respectively) vs the dose-increase group (39%; both P<0.001). Combination-group patients incurred significantly greater costs vs the dose-increase group ($2805 vs $1767, respectively; P<0.001).

Conclusion

Results suggest that increasing escitalopram dose in patients responding inadequately to 10mg is associated with higher persistence rates vs the other treatment approaches. Receiving an increased dose of escitalopram was associated with significantly lower costs than combining escitalopram 10mg with another antidepressant.

Meta-analysis: Risk of dry mouth with second generation antidepressants

OBJECTIVE

The goal of this meta-analysis was to quantify the risk of dry mouth associated with commonly prescribed antidepressant agents and examine the potential implications of medication class, dose, and pharmacodynamics and dose on risk of treatment-induced dry mouth.

DATA SOURCES AND STUDY SELECTION

A PubMed search was conducted to identify double-blind, randomized, placebo-controlled trials examining the efficacy and tolerability of second generation antidepressant medications for adults with depressive disorders, anxiety disorders, and OCD.

DATA EXTRACTION

A random-effects meta-analysis was used to quantify the pooled risk ratio of treatment-emergent dry mouth with second generation antidepressants compared to placebo. Stratified subgroup analysis and meta-regression was utilized to further examine the effects antidepressant agent, class, dosage, indication, and receptor affinity profile on the measured risk of dry mouth.

RESULTS

99 trials involving 20,868 adults. SNRIs (Relative Risk (RR)=2.24, 95% Confidence Interval (CI): 1.95-2.58, z=11.2, p<0.001) were associated with a significantly greater risk of dry mouth (test for subgroup differences χ²=7.6, df=1; p=0.006) compared to placebo than SSRIs (RR=1.65, 95% CI: 1.39-1.95, z=5.8, p<0.001). There was a significant difference found in the risk of dry mouth between diagnostic indications within the SNRI class (test for subgroup differences χ²=9.63, df=1; p=0.002). Anxiety diagnoses (RR=2.78, 95% CI: 2.29-3.38, z=10.32, p<0.001) were associated with a greater risk of dry mouth compared to depression (RR=1.80, 95% CI: 1.48-2.18, z=5.85, p<0.001). Decreased affinity for Alpha-1 (PE=0.18, 95% CI: 0.07-0.28, z=3.26, p=0.001) and Alpha-2 (PE=0.49, 95% CI: 0.22-0.75, z=3.64, p<0.001) receptors and SERT (PE=0.07, 95% CI: 0.01-0.14, z=2.10, p<0.05) was significantly associated with increased risk of dry mouth.

CONCLUSIONS

The current meta-analysis suggests that SSRIs, SNRIs, and atypical antidepressants are all associated with varying degrees of increased risk of dry mouth. SNRIs were associated with a significantly greater risk of dry mouth compared to SSRIs.

Computational Model of Antidepressant Response Heterogeneity as Multi-pathway Neuroadaptation

Current hypotheses cannot fully explain the clinically observed heterogeneity in antidepressant response. The therapeutic latency of antidepressants suggests that therapeutic outcomes are achieved not by the acute effects of the drugs, but rather by the homeostatic changes that occur as the brain adapts to their chronic administration. We present a computational model that represents the known interactions between the monoaminergic neurotransmitter-producing brain regions and associated non-monoaminergic neurotransmitter systems, and use the model to explore the possible ways in which the brain can homeostatically adjust to chronic antidepressant administration. The model also represents the neuron-specific neurotransmitter receptors that are known to adjust their strengths (expressions or sensitivities) in response to chronic antidepressant administration, and neuroadaptation in the model occurs through sequential adjustments in these receptor strengths. The main result is that the model can reach similar levels of adaptation to chronic administration of the same antidepressant drug or combination along many different pathways, arriving correspondingly at many different receptor strength configurations, but not all of those adapted configurations are also associated with therapeutic elevations in monoamine levels. When expressed as the percentage of adapted configurations that are also associated with elevations in one or more of the monoamines, our modeling results largely agree with the percentage efficacy rates of antidepressants and antidepressant combinations observed in clinical trials. Our neuroadaptation model provides an explanation for the clinical reports of heterogeneous outcomes among patients chronically administered the same antidepressant drug regimen.

Efficacy and tolerability of escitalopram in treatment of major depressive disorder with anxiety symptoms: a 24-week, open-label, prospective study in Chinese population

BACKGROUND

Significant anxiety symptoms are associated with poor clinical course and outcome in major depressive disorder (MDD). This single-arm, open-label study aimed to evaluate the efficacy and tolerability of escitalopram treatment in patients with MDD and anxiety symptoms.

METHODS

Adult patients with MDD and anxiety symptoms (Montgomery-Asberg Depression Rating Scale [MADRS] ≥22 and Hamilton Anxiety Rating Scale [HAM-A] ≥14) were enrolled and received escitalopram (10-20 mg/day) treatment for 24 weeks. Symptom status was assessed by MADRS, 17-item-Hamilton Depression Rating Scale, HAM-A, and Clinical Global Impression Scale at baseline and the following visits. Quality of life was assessed by Short Form-12, and safety was evaluated by adverse events, laboratory investigations, vital signs, and physical findings.

RESULTS

Overall, 200 of 318 (66.2%) enrolled patients completed the 24-week treatment. The remission (MADRS ≤10 and HAM-A ≤7) rate in the full analysis set (N=285) was 73.3% (95% confidence interval: 67.80, 78.38) at week 24. Mean (± standard deviation) MADRS total score was 33.4 (±7.13) and HAM-A score was 27.6 (±7.26) at baseline, which reduced to 6.6 (±10.18) and 6.0 (±8.39), respectively, at week 24. Patients with higher baseline depression and anxiety level took longer to achieve similar remission rates. Overall, 80 of the 302 (26.5%) patients included in the safety set reported at least 1 treatment-emergent adverse event (TEAE). Most frequently reported TEAEs (>2%) were headache (4.0%), nasopharyngitis (3.6%), nausea (3.0%), and dizziness (2.6%). Serious TEAEs were reported by 1.3% patients; no deaths were reported.

CONCLUSION

Escitalopram 10-20 mg/day was effective and well-tolerated in the long-term treatment of MDD with anxiety symptoms in adult Chinese population.

Assessment of health-related quality of life, mental health status and psychological distress based on the type of pharmacotherapy used among patients with depression

PURPOSE

Effectiveness of antidepressants is generally comparable between and within classes. However, real-world studies on antidepressant treatment and its consequences on the overall quality of life and mental health of individuals are limited. The purpose of this study was to examine the association of specific class of antidepressants with the health-related quality of life, psychological distress and self-reported mental health of individuals suffering from depression who are on monotherapy.

METHODS

This retrospective, longitudinal study included individuals with depression who were on antidepressant monotherapy, using data from 2008 to 2011 Medical Expenditure Panel Survey (MEPS). Changes in health-related quality of life, self-reported mental health and psychological distress over a year's time were observed. A multinomial logistic regression model was built to examine the association between the class of antidepressant medications and the dependent variables.

RESULTS

A total of 688 adults met the study inclusion criteria. No significant difference was observed in the change in Physical Component Summary (PCS), self-reported mental health and psychological distress based on the class of antidepressants. However, individuals on serotonin-norepinephrine reuptake inhibitors (SNRIs) (OR 0.337, 95 % CI 0.155-0.730) were significantly less likely to show improvement on Mental Component Summary (MCS) scores as compared to those on selective serotonin reuptake inhibitors (SSRIs).

CONCLUSIONS

The study findings suggest that practitioners should be aware of the differences in the health-related quality of life of those taking SSRIs versus other classes of antidepressants. Further research needs to be done to determine the reason for SSRIs to show greater improvement on mental health as compared to SNRIs.

What to expect from a third step in treatment resistant depression: A prospective open study on escitalopram

OBJECTIVES

Only few studies investigated treatment strategies for treatment resistant depression (TRD). The objective of this multicentre study was to evaluate TRD patients who did not respond to at least two antidepressants.

METHODS

A total of 417 patients, who failed to respond to a previous retrospectively assessed antidepressant (AD1), were firstly included in a 6-week venlafaxine treatment (AD2); secondly, those who failed to respond were treated for further 6 weeks with escitalopram (AD3).

RESULTS

Out of 417 patients who had failed to respond to previous treatment (AD1), 334 completed treatment with venlafaxine to prospectively define TRD. In the intent to treat (ITT) population in the first phase of the trial (AD2), responders to venlafaxine were 151 (36.21%) out of which remitters were 83 (19.90%). After phase one, 170 non-responders, defined as TRD, were included in the second phase and 157 completed the course. Of the 170 ITT entering the second phase (AD3), responders to escitalopram were 71 (41.76%) out of which remitters were 39 (22.94%). After the third treatment, patients showed a dropout rate of 7.65% and a rate of presence of at least one serious adverse event of 19.18%.

CONCLUSIONS

Relevant rates of response and remission may be observed after a third line treatment in patients resistant to two previous treatments. A relevant limitation of this study was represented by the design: naturalistic, non-randomized, open-label, without a control sample and with unblinded raters.

Blockade of the high-affinity noradrenaline transporter (NET) by the selective 5-HT reuptake inhibitor escitalopram: an in vivo microdialysis study in mice

BACKGROUND AND PURPOSE

Escitalopram, the S(+)-enantiomer of citalopram is the most selective 5-HT reuptake inhibitor approved. Although all 5-HT selective reuptake inhibitors (SSRIs) increase extracellular levels of 5-HT ([5-HT](ext)). some also enhance, to a lesser extent, extracellular levels of noradrenaline ([NA](ext)). However, the mechanisms by which SSRIs activate noradrenergic transmission in the brain remain to be determined.

EXPERIMENTAL APPROACH

This study examined the effects of escitalopram, on both [5-HT](ext) and [NA](ext) in the frontal cortex (FCx) of freely moving wild-type (WT) and mutant mice lacking the 5-HT transporter (SERT(-/-)) by using intracerebral microdialysis. We explored the possibilities that escitalopram enhances [NA](ext), either by a direct mechanism involving the inhibition of the low- or high-affinity noradrenaline transporters, or by an indirect mechanism promoted by [5-HT](ext) elevation. The forced swim test (FST) was used to investigate whether enhancing cortical [5-HT](ext) and/or [NA](ext) affected the antidepressant-like activity of escitalopram.

KEY RESULTS

In WT mice, a single systemic administration of escitalopram produced a significant increase in cortical [5-HT](ext) and [NA](ext). As expected, escitalopram failed to increase cortical [5-HT](ext) in SERT(-/-) mice, whereas its neurochemical effects on [NA](ext) persisted in these mutants. In WT mice subjected to the FST, escitalopram increased swimming parameters without affecting climbing behaviour. Finally, escitalopram, at relevant concentrations, failed to inhibit cortical noradrenaline and 5-HT uptake mediated by low-affinity monoamine transporters.

CONCLUSIONS AND IMPLICATIONS

These experiments suggest that escitalopram enhances, although moderately, cortical [NA](ext) in vivo by a direct mechanism involving the inhibition of the high-affinity noradrenaline transporter (NET).

Early and sustained improvement with vilazodone in adult patients with major depressive disorder: post hoc analyses of two phase III trials

OBJECTIVE

To retrospectively examine the timing of depressive symptom improvement in patients treated with vilazodone, a selective serotonin reuptake inhibitor (SSRI) and 5-HT1A partial agonist.

RESEARCH DESIGN AND METHODS

Post hoc analyses were conducted on pooled data from two phase III, multicenter, 8 week, double-blind, randomized, controlled trials (RCTs) of vilazodone 40 mg/day or placebo in adult patients with major depressive disorder (MDD).

CLINICAL TRIAL REGISTRATION

Randomized controlled trial 1: ClinicalTrials.gov identifier: NCT00285376, http://ClinicalTrials.gov/ct2/show/NCT00285376 ; randomized controlled trial 2: ClinicalTrials.gov identifier: NCT00683592, http://ClinicalTrials.gov/ct2/show/NCT00683592.

MAIN OUTCOME MEASURES

Montgomery-Åsberg Depression Rating Scale (MADRS) total score least squares (LS) mean change from baseline to Week 8; MADRS single items LS mean change from baseline; MADRS responder analyses: response = ≥50% reduction in baseline score; cumulative response = proportion of patients at each assessment who achieved response that was sustained at all subsequent weeks; sustained response = ≥50% reduction in baseline MADRS total score at last two visits; and sustained response plus MADRS score ≤12 at the last two visits of the study.

RESULTS

LS mean difference (LSMD) and 95% confidence interval (95% CI) for change from baseline to Week 8 was significantly greater in favor of vilazodone versus placebo (-2.8 [-4.1 to -1.4]; p < 0.0001); differences between vilazodone and placebo were statistically significant beginning at Week 1. Early improvement in depressive symptoms was suggested by statistically significant separation from placebo on seven of ten MADRS single items as early as Week 1 or Week 2. A significantly greater proportion of vilazodone patients achieved response using all responder criteria, with early and sustained improvement consistently observed.

CONCLUSIONS

Early and sustained improvement of depressive symptoms was retrospectively observed in patients treated with vilazodone; early findings may be related to overall treatment outcomes.

A review of vilazodone, serotonin, and major depressive disorder

Objective: To review the mechanism of selective serotonin reuptake inhibitor (SSRI)–mediated serotonergic neurotransmission, focusing on serotonin 1A (5-HT_1A) autoreceptors, which are proposed to be involved in delaying therapeutic efficacy. Vilazodone was specifically designed to function both as an SSRI and a partial agonist at 5-HT_1A receptors. This combined mechanism is proposed to decrease time to efficacy, minimize sexual side effects, and provide concomitant anxiolytic properties.

Data Sources: A PubMed search of all English-language articles from January 1990 to January 2013 was conducted using the search terms depression and 5-HT_1A, depression and buspirone, depression and pindolol, and vilazodone.

Study Selection: We found 47 articles and abstracts that were selected for inclusion on the basis of information about the pharmacology of 5-HT_1A receptors and the clinical data on pindolol, buspirone, and vilazodone in depression.

Data Extraction: This review summarizes current literature involving antidepressant activity, the role of 5-HT_1A autoreceptors, and clinical trials involving serotonin reuptake inhibition in conjunction with 5-HT_1A agonists and partial agonists, with a focus on vilazodone.

Results:Vilazodone has demonstrated efficacy in 2 large, randomized, double-blind, placebo-controlled trials in major depressive disorder. Results suggest that vilazodone has a low incidence of sexual side effects and is effective in patients with high levels of anxiety. A pooled analysis shows evidence of significant symptom reduction after only 1 week of therapy.

Conclusions: If future studies corroborate the clinical benefits attributed to its mechanism of action, vilazodone may show potential advantages in terms of onset of action, sexual side effects, and anxiolytic activity in patients with major depressive disorder.

Levomilnacipran for major depressive disorder: a systematic review of the efficacy and safety profile for this newly approved antidepressant--what is the number needed to treat, number needed to harm and likelihood to be helped or harmed?

OBJECTIVE

To describe the efficacy and safety of levomilnacipran (extended-release capsules) for the treatment of major depressive disorder (MDD).

DATA SOURCES

The pivotal registration trials were accessed by querying http://www.ncbi.nlm.nih.gov/pubmed/, http://www.clinicaltrialsregister.eu and http://www.clinicaltrials.gov for the search terms 'levomilnacipran' and 'F2695', and by obtaining posters presented at congresses. Product labelling provided additional information.

STUDY SELECTION

All available clinical reports of studies were identified.

DATA EXTRACTION

Descriptions of the principal results and calculation of number needed to treat (NNT) and number needed to harm (NNH) for relevant dichotomous outcomes were extracted from the available study reports and other sources of information.

DATA SYNTHESIS

Levomilnacipran (1S, 2R-milnacipran) is a potent and selective serotonin-norepinephrine reuptake inhibitor with greater potency for inhibition of norepinephrine relative to serotonin reuptake. Approval for the treatment of MDD was based on a clinical development program that included one 10-week Phase II and four 8-week Phase III randomised placebo-controlled clinical trials in outpatients with MDD where levomilnacipran was titrated to target doses ranging from 40 to 120 mg taken once daily. Four of the five trials demonstrated efficacy as measured by the Montgomery Asberg Depression Rating Scale, with a NNT for response vs. placebo of 9 (95% CI 7-15), and for remission, 14 (95% CI 10-28). Levomilnacipran also demonstrated superiority over placebo as measured by improvement in the Sheehan Disability Scale functional impairment total score. NNH vs. placebo for discontinuation because an adverse event (AE) across all five trials was 19 (95% CI 14-28). The most commonly encountered AEs (incidence ≥ 5% and at least twice the rate of placebo) as identified in product labelling were nausea, hyperhidrosis, constipation, heart rate increased, erectile dysfunction in men, vomiting, tachycardia and palpitations, with NNH values vs. placebo of 10 (95% CI 8-12), 15 (95% CI 12-19), 17 (95% CI 13-24), 21 (95% CI 17-29), 20 (95% CI 14-36), 25 (95% CI 20-37), 25 (95% CI 19-40) and 30 (95% CI 22-49), respectively. Levomilnacipran was not associated with clinically relevant weight change in the short-term trials or in a 48-week open-label extension trial. Mean changes from baseline in systolic blood pressure (BP), diastolic BP and heart rate were +3.0 mmHg, +3.2 mm Hg and +7.4 bpm for levomilnacipran, and -0.4 mmHg, no change and -0.3 bpm for placebo, respectively. Categorical shift in BP from normal or prehypertension at baseline to stage 1 or stage 2 hypertension at end of study was 10.4% for levomilnacipran vs. 7.1% for placebo, for a NNH of 31 (95% CI 18-94).

CONCLUSIONS

Levomilnacipran represents another option for the treatment of MDD. Levomilnacipran appears to have a favourable weight-gain profile. Additional controlled data regarding long-term efficacy and comparative effectiveness will help characterise this new agent.

Does adding noradrenaline reuptake inhibition to selective serotonin reuptake inhibition improve efficacy in patients with depression? A systematic review of meta-analyses and large randomised pragmatic trials

Selective serotonin reuptake inhibitors (SSRIs) are recommended as first-line pharmacological treatment for depression and are the most commonly prescribed class of antidepressants. However, there is substantial evidence that noradrenaline has a role in the pathogenesis and treatment of depression. This review aims to examine the evidence of including noradrenaline reuptake inhibition with serotonin reuptake inhibition with respect to increasing efficacy in the treatment of depression. Evidence from meta-analysis of randomised controlled trials (RCTs) and randomised pragmatic trials was found in support of greater efficacy of the serotonin noradrenaline reuptake inhibitors (SNRIs), venlafaxine and duloxetine, in moderate to severe depression compared to SSRIs but no evidence was found for superiority of milnacipran. There is sufficient current evidence that demonstrates an increase in efficacy, when noradrenaline reuptake is added to serotonin (5-HT) reuptake, to suggest that patients with severe depression or those who have failed to reach remission with a SSRI may benefit from treatment with a SNRI. However, as these conclusions are drawn from the evidence derived from meta-analyses and pragmatic trials, large adequately powered RCTs using optimal dosing regimens and clinically relevant outcome measures in severe depression and SSRI treatment failures are still required to confirm these findings.

Remission with venlafaxine extended release or selective serotonin reuptake inhibitors in depressed patients: a randomized, open-label study

BACKGROUND

This randomized, open-label, rater-blinded, multicenter study compared treatment outcomes with the serotonin-norepinephrine reuptake inhibitor (SNRI) venlafaxine extended release (ER) with selective serotonin reuptake inhibitors (SSRIs) in primary care patients with major depressive disorder.

METHOD

Study data were collected from November 29, 2000, to March 4, 2003. Outpatients who met diagnostic criteria for major depressive disorder according to the Mental Health Screener, a computer-administered telephone interview program that screens for the most common mental disorders, and had a total score on the 17-item Hamilton Depression Rating Scale (HDRS(17)) ≥ 20 were randomly assigned to receive up to 6 months of open-label venlafaxine ER 75-225 mg/d (n = 688) or an SSRI (n = 697): fluoxetine 20-80 mg/d, paroxetine 20-50 mg/d, citalopram 20-40 mg/d, and sertraline 50-200 mg/d. The primary outcome was remission (HDRS(17) score ≤ 7) at study end point using the last-observation-carried-forward method to account for early termination. A mixed-effects model for repeated measures (MMRM) analysis evaluated secondary outcome measures.

RESULTS

Fifty-one percent of patients completed the study. Month 6 remission rates did not differ significantly for venlafaxine ER and the SSRIs (35.5% vs 32.0%, respectively; P = .195). The MMRM analysis of HDRS(17) scores also did not differ significantly (P = .0538). Significant treatment effects favoring the venlafaxine ER group were observed for remission rates at days 30, 60, 90, and 135 and a survival analysis of time to remission (P = .006), as well as Clinical Global Impressions-severity of illness scale (P = .0002); Hospital Anxiety and Depression Scale-Anxiety subscale (P = .03); 6-item Hamilton Depression Rating Scale, Bech version (P = .009); and Quick Inventory of Depressive Symptomatology-Self-Report (P = .0003).

CONCLUSIONS

Remission rates for patients treated with venlafaxine ER or an SSRI did not differ significantly after 6 months of treatment. Results of most secondary analyses suggested that SNRI treatment had a greater antidepressant effect versus the SSRIs studied.

Escitalopram, an antidepressant with an allosteric effect at the serotonin transporter--a review of current understanding of its mechanism of action

RATIONALE

Escitalopram is a widely used antidepressant for the treatment of patients with major depression. It is the pure S-enantiomer of racemic citalopram. Several clinical trials and meta-analyses indicate that escitalopram is quantitatively more efficacious than many other antidepressants with a faster onset of action.

OBJECTIVE

This paper reviews current knowledge about the mechanism of action of escitalopram.

RESULTS

The primary target for escitalopram is the serotonin transporter (SERT), which is responsible for serotonin (or 5-hydroxytryptamine [5-HT]) reuptake at the terminals and cell bodies of serotonergic neurons. Escitalopram and selective serotonin reuptake inhibitors bind with high affinity to the 5-HT binding site (orthosteric site) on the transporter. This leads to antidepressant effects by increasing extracellular 5-HT levels which enhance 5-HT neurotransmission. SERT also has one or more allosteric sites, binding to which modulates activity at the orthosteric binding site but does not directly affect 5-HT reuptake by the transporter. In vitro studies have shown that through allosteric binding, escitalopram decreases its own dissociation rate from the orthosteric site on the SERT. R-citalopram, the nontherapeutic enantiomer in citalopram, is also an allosteric modulator of SERT but can inhibit the actions of escitalopram by interfering negatively with its binding. Both nonclinical studies and some clinical investigations have demonstrated the cellular, neurochemical, neuroadaptive, and neuroplastic changes induced by escitalopram with acute and chronic administration.

CONCLUSIONS

The findings from binding, neurochemical, and neurophysiological studies may provide a mechanistic rationale for the clinical difference observed with escitalopram compared to other antidepressant therapies.

Strategies to achieve clinical effectiveness: refining existing therapies and pursuing emerging targets

BACKGROUND

Clinical effectiveness reflects a balance between efficacy and tolerability as well as patient satisfaction and overall improvement in quality of life and function. This is of particular importance when considering the long term use of antidepressant therapies for relapse prevention.

METHODS

The purpose of this review is to explore methods to enhance the modest efficacy and effectiveness outcomes reported with current antidepressant strategies. Two strategies are addressed: a) Doing better with existing treatments and b) pursuing novel targets beyond the monoamine system for new antidepressant drug development.

RESULTS

In the first instance, it is important to consider the balance between antidepressant efficacy and tolerability for individual patients and also be aware of evidence supporting superiority of one agent over others. Both sequential and concurrent combination therapies with existing antidepressants are also reviewed. The second approach involves a review of emerging novel pharmacological treatments based on biomarker research. Unique targets where antidepressant treatments appear effective include the melatonergic, glutamatergic, neurotrophic, cytokine, and neuropeptide systems.

CONCLUSIONS

While agomelatine represents an example of a clinically available antidepressant that targets melatonin receptors, drugs that act on other candidate systems are still in the development phase.

Recommendations for the prevention, diagnosis, and treatment of chronic hepatitis B and C in special population groups (migrants, intravenous drug users and prison inmates)

The global spread of hepatitis B virus (HBV) and hepatitis C virus (HCV), their high chronicity rates and their progression to cirrhosis and hepatocellular carcinoma, are major public health problems. Research and intervention programmes for special population groups are needed in order to assess their infection risk and set up suitable prevention and control strategies. Aim of this paper is to give health care professionals information on HBV and HCV infections amongst migrants, drug users and prison inmates. The manuscript is an official Position Paper on behalf of the following Scientific Societies: Italian Association for the Study of the Liver (A.I.S.F.), Italian Society of Infectious and Tropical Diseases (S.I.M.I.T.), Italian Federation Department's Operators and Addiction Services (FederSerD), Italian Prison Medicine and Healthcare Society (S.I.M.S.Pe.). The considered population groups, having a high prevalence HBV and HCV infections, require specific interventions. In this context, the expression "special population" refers to specific vulnerable groups at risk of social exclusion, such as migrants, prison inmates, and intravenous drug users. When dealing with special population groups, social, environmental and clinical factors should be considered when selecting candidates for therapy as indicated by national and international guidelines.

Treatment adherence and persistence with duloxetine, venlafaxine XR, and escitalopram among patients with major depressive disorder and chronic pain-related diseases

OBJECTIVE

Chronic pain is prevalent in patients with major depressive disorder (MDD). This study compared adherence and persistence rates among MDD patients with comorbid chronic pain-related diseases (CPD, including fibromyalgia, diabetes with neurological manifestations, osteoarthritis, low back pain, and headache) for three antidepressants: duloxetine, venlafaxine XR, and escitalopram.

RESEARCH DESIGN AND METHODS

A retrospective analysis was conducted of 15,523 adult MDD patients with CPD in the MarketScan Commercial Claims and Encounters Database who started on one of the study medications between 07/01/06 and 06/30/07. Patients were followed-up for 6 months. Adherence was reported using a medication possession ratio ≥0.8. Persistence was measured using persistence rates (proportions of patients who continuously refilled prescriptions during 6 months) and duration of therapy (number of days patients remained on the study medication before a prescription gap over 30 days). Multivariate logistic regression on adherence and persistence rates and linear regression on duration of therapy adjusting for patient and prescription characteristics were conducted.

RESULTS

Patients on duloxetine had a higher adherence rate (46.03%) than those on venlafaxine XR (42.94%; p = 0.0033) or escitalopram (37.27%; p < 0.0001). Patients on duloxetine also had a higher persistence rate and longer duration of therapy (43.66%, 117.82 days) than did patients treated with venlafaxine XR (40.38%; p = 0.0017; 114.24 days; p = 0.009) or escitalopram (33.86%; p < 0.0001; 105.73 days; p < 0.0001). These differences were still significant after adjusting for patient and prescription characteristics (p < 0.05). Sensitivity analyses found similar patterns using an allowable gap for refill of 15 days.

CONCLUSIONS

Among commercially insured MDD patients with CPD, duloxetine-treated patients had higher adherence and persistence rates than did patients treated with venlafaxine XR or escitalopram during 6 months after medication initiation. Future studies should examine the clinical and economic implications of these differences.

LIMITATIONS

This study has limitations such as possible selection bias using secondary database analysis.

Comparative efficacy of escitalopram in the treatment of major depressive disorder

BACKGROUND

Escitalopram is an allosteric selective serotonin reuptake inhibitor (SSRI) with some indication of superior efficacy in the treatment of major depressive disorder. In this systematic review, we critically evaluate the evidence for comparative efficacy and tolerability of escitalopram, focusing on pooled and meta-analysis studies.

METHODS

A literature search was conducted for escitalopram studies that quantitatively synthesized data from comparative randomized controlled trials in MDD. Studies were excluded if they did not focus on efficacy, involved primarily subgroups of patients, or synthesized data included in subsequent studies. Outcomes extracted from the included studies were weighted mean difference or standard mean difference, response and remission rates, and withdrawal rate owing to adverse events.

RESULTS

The search initially identified 24 eligible studies, of which 12 (six pooled analysis and six meta-analysis studies) met the criteria for review. The pooled and meta-analysis studies with citalopram showed significant but modest differences in favor of escitalopram, with weighted mean differences ranging from 1.13 to 1.73 points on the Montgomery Asberg Depression Rating Scale, response rate differences of 7.0%-8.3%, and remission rate differences of 5.1%-17.6%. Pooled analysis studies showed efficacy differences compared with duloxetine and with serotonin noradrenaline reuptake inhibitors combined, but meta-analysis studies did not. The effect sizes of the efficacy differences increased in the severely depressed patient subgroups.

CONCLUSION

Based on pooled and meta-analysis studies, escitalopram demonstrates superior efficacy compared with citalopram and with SSRIs combined. Escitalopram shows similar efficacy to serotonin noradrenaline reuptake inhibitors but the number of trials in these comparisons is limited. Efficacy differences are modest but clinically relevant, especially in more severely depressed patients.

The noradrenergic action in antidepressant treatments: pharmacological and clinical aspects

Even though noradrenaline has been recognized as one of the key neurotransmitters in the pathophysiology of major depression (MD), noradrenergic compounds have been less extensively utilized in clinical practice, compared to selective serotonin reuptake inhibitors (SSRIs). The development of the first selective noradrenergic reuptake inhibitor (NRI), Reboxetine, has not substantially changed the state of the art. In addition, Atomoxetine, a relatively pure NRI used for the treatment of ADHD, has shown mixed results when administered in augmentation to depressed subjects. Through a Medline search from 2000 to 2010, the present article provides an updated overview of the main pharmacological and clinical aspects of antidepressant classes that, partially or selectively, act on the noradrenergic systems. The noradrenergic action plays an important clinical effect in different antidepressant classes, as confirmed by the efficacy of dual action antidepressants such as the serotonin noradrenaline reuptake inhibitors (SNRIs), the noradrenergic and dopaminergic reuptake inhibitor (NDRI) Bupropion, and other compounds (e.g., Mianserin, Mirtazapine), which enhance the noradrenergic transmission. In addition, many tricyclics, such as Desipramine and Nortriptyline, have prevalent noradrenergic effect. Monoamine oxidase inhibitors (MAOIs), moreover, block the breakdown of serotonin, noradrenaline, dopamine and increase the availability of these monoamines. A novel class of antidepressants--the triple reuptake inhibitors--is under development to selectively act on serotonin, noradrenaline, and dopamine. Finally, the antidepressant effect of the atypical antipsychotic Quetiapine, indicated for the treatment of bipolar depression, is likely to be related to the noradrenergic action of its metabolite Norquetiapine. Even though a pure noradrenergic action might not be sufficient to obtain a full antidepressant effect, a pronoradrenergic action represents an important element for increasing the efficacy of mixed action antidepressants. In particular, the noradrenergic action seemed to be related to the motor activity, attention, and arousal.

Getting the balance right: Established and emerging therapies for major depressive disorders

Major depressive disorder (MDD) is a common and serious illness of our times, associated with monoamine deficiency in the brain. Moreover, increased levels of cortisol, possibly caused by stress, may be related to depression. In the treatment of MDD, the use of older antidepressants such as monoamine oxidase inhibitors and tricyclic antidepressants is decreasing rapidly, mainly due to their adverse effect profiles. In contrast, the use of serotonin reuptake inhibitors and newer antidepressants, which have dual modes of action such as inhibition of the serotonin and noradrenaline or dopamine reuptake, is increasing. Novel antidepressants have additive modes of action such as agomelatine, a potent agonist of melatonin receptors. Drugs in development for treatment of MDD include triple reuptake inhibitors, dual-acting serotonin reuptake inhibitors and histamine antagonists, and many more. Newer antidepressants have similar efficacy and in general good tolerability profiles. Nevertheless, compliance with treatment for MDD is poor and may contribute to treatment failure. Despite the broad spectrum of available antidepressants, there are still at least 30% of depressive patients who do not benefit from treatment. Therefore, new approaches in drug development are necessary and, according to current research developments, the future of antidepressant treatment may be promising.

Escitalopram--translating molecular properties into clinical benefit: reviewing the evidence in major depression

The majority of currently marketed drugs contain a mixture of enantiomers; however, recent evidence suggests that individual enantiomers can have pharmacological properties that differ importantly from enantiomer mixtures. Escitalopram, the S-enantiomer of citalopram, displays markedly different pharmacological activity to the R-enantiomer. This review aims to evaluate whether these differences confer any significant clinical advantage for escitalopram over either citalopram or other frequently used antidepressants. Searches were conducted using PubMed and EMBASE (up to January 2009). Abstracts of the retrieved studies were reviewed independently by both authors for inclusion. Only those studies relating to depression or major depressive disorder were included. The search identified over 250 citations, of which 21 studies and 18 pooled or meta-analyses studies were deemed suitable for inclusion. These studies reveal that escitalopram has some efficacy advantage over citalopram and paroxetine, but no consistent advantage over other selective serotonin reuptake inhibitors. Escitalopram has at least comparable efficacy to available serotonin-norepinephrine reuptake inhibitors, venlafaxine XR and duloxetine, and may offer some tolerability advantages over these agents. This review suggests that the mechanistic advantages of escitalopram over citalopram translate into clinical efficacy advantages. Escitalopram may have a favourable benefit-risk ratio compared with citalopram and possibly with several other antidepressant agents.

Escitalopram versus serotonin noradrenaline reuptake inhibitors as second step treatment for patients with major depressive disorder: a pooled analysis

The objective of this study was to evaluate the efficacy and tolerability of escitalopram versus serotonin and noradrenaline reuptake inhibitors (SNRIs) as second step treatment (defined operationally as poor response or intolerability to an antidepressant) for major depressive disorder (MDD). Results from all eligible head-to-head clinical trials of MDD (which excluded patients who earlier failed two or more antidepressants) sponsored by Lundbeck or Forest comparing escitalopram and SNRIs (venlafaxine and duloxetine) were pooled. A second step treatment subgroup was identified, defined as patients treated earlier with any antidepressant in the 6-month period before baseline. Data from three clinical trials were included in the analysis; 132 patients were identified in the second step treatment subgroup (66 in each of the escitalopram and SNRI groups). The primary efficacy analysis showed that the patients subsequently treated with escitalopram had significantly lower Montgomery Asberg Depression Rating Scale total scores after 8 weeks compared with those subsequently treated with SNRIs (difference = -6.4, P<0.0001). Escitalopram treatment was also associated with higher clinical response (73 vs. 44%, P=0.0004) and remission rates (62 vs. 41%, P=0.0083) compared with subsequent treatment with SNRIs. Escitalopram showed a better tolerability profile with lower all-cause withdrawals from study (9 vs. 23%, P<0.04) and lower withdrawals because of adverse events (2 vs. 17%, P<0.003). In conclusion, escitalopram is associated with a better efficacy and tolerability profile than SNRIs (duloxetine and venlafaxine) when used as a second step treatment in patients with MDD. These results should be confirmed in prospective randomized clinical trials.