A meta-analysis of the efficacy and tolerability of paroxetine versus tricyclic antidepressants in the treatment of major depression

Major depressive disorder: Validated treatments and future challenges

Depression is a prevalent psychiatric disorder that often leads to poor quality of life and impaired functioning. Treatment during the acute phase of a major depressive episode aims to help the patient reach a remission state and eventually return to their baseline level of functioning. Pharmacotherapy, especially selective serotonin reuptake inhibitors antidepressants, remains the most frequent option for treating depression during the acute phase, while other promising pharmacological options are still competing for the attention of practitioners. Depression-focused psychotherapy is the second most common option for helping patients overcome the acute phase, maintain remission, and prevent relapses. Electroconvulsive therapy is the most effective somatic therapy for depression in some specific situations; meanwhile, other methods have limits, and their specific indications are still being studied. Combining medications, psychotherapy, and somatic therapies remains the most effective way to manage resistant forms of depression.

Antidepressant drug paroxetine blocks the open pore of Kv3.1 potassium channel

In patients with epilepsy, depression is a common comorbidity but difficult to be treated because many antidepressants cause pro-convulsive effects. Thus, it is important to identify the risk of seizures associated with antidepressants. To determine whether paroxetine, a very potent selective serotonin reuptake inhibitor (SSRI), interacts with ion channels that modulate neuronal excitability, we examined the effects of paroxetine on Kv3.1 potassium channels, which contribute to highfrequency firing of interneurons, using the whole-cell patch-clamp technique. Kv3.1 channels were cloned from rat neurons and expressed in Chinese hamster ovary cells. Paroxetine reversibly reduced the amplitude of Kv3.1 current, with an IC₅₀ value of 9.43 µM and a Hill coefficient of 1.43, and also accelerated the decay of Kv3.1 current. The paroxetine-induced inhibition of Kv3.1 channels was voltage-dependent even when the channels were fully open. The binding (k₊₁) and unbinding (k₋₁) rate constants for the paroxetine effect were 4.5 µM⁻¹s⁻¹ and 35.8 s⁻¹, respectively, yielding a calculated K_D value of 7.9 µM. The analyses of Kv3.1 tail current indicated that paroxetine did not affect ion selectivity and slowed its deactivation time course, resulting in a tail crossover phenomenon. Paroxetine inhibited Kv3.1 channels in a usedependent manner. Taken together, these results suggest that paroxetine blocks the open state of Kv3.1 channels. Given the role of Kv3.1 in fast spiking of interneurons, our data imply that the blockade of Kv3.1 by paroxetine might elevate epileptic activity of neural networks by interfering with repetitive firing of inhibitory neurons.

Blockade of Kv1.5 by paroxetine, an antidepressant drug

Paroxetine, a selective serotonin reuptake inhibitor (SSRI), has been reported to have an effect on several ion channels including human ether-a-go-go-related gene in a SSRI-independent manner. These results suggest that paroxetine may cause side effects on cardiac system. In this study, we investigated the effect of paroxetine on Kv1.5, which is one of cardiac ion channels. The action of paroxetine on the cloned neuronal rat Kv1.5 channels stably expressed in Chinese hamster ovary cells was investigated using the whole-cell patch-clamp technique. Paroxetine reduced Kv1.5 whole-cell currents in a reversible concentration-dependent manner, with an IC 50 value and a Hill coefficient of 4.11 µM and 0.98, respectively. Paroxetine accelerated the decay rate of inactivation of Kv1.5 currents without modifying the kinetics of current activation. The inhibition increased steeply between -30 and 0 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to 0 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance δ of 0.32. The binding (k+1) and unbinding (k-1) rate constants for paroxetine-induced block of Kv1.5 were 4.9 µM(-1)s(-1) and 16.1 s(-1), respectively. The theoretical K D value derived by k-1/k+1 yielded 3.3 µM. Paroxetine slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of paroxetine, were superimposed. Inhibition of Kv1.5 by paroxetine was use-dependent. The present results suggest that paroxetine acts on Kv1.5 currents as an open-channel blocker.

Phytopharmaceutical treatment of anxiety, depression, and dementia in the elderly: evidence from randomized, controlled clinical trials

Based on subgroup analyses of randomized, controlled clinical trials, we review the efficacy of three phytopharmaceutical drugs, respectively of the corresponding active substances silexan® (WS® 1265, lavender oil) in anxiety disorders, WS® 5570 (Hypericum extract) in major depression, and EGb 761® (Ginkgo biloba extract) in Alzheimer, vascular, or mixed type dementia, in elderly patients aged ≥ 60 years. Four trials were eligible in each indication. Meta-analyses and analyses based on pooled raw data showed that the three drugs were significantly superior to placebo in the elderly subset, and that their treatment effects reflected in the main outcome measures (Hamilton Anxiety scale, Hamilton Depression scale, Neuropsychiatric Inventory) were comparable with those observed in the original trials without age restrictions. The results confirm the efficacy of the three herbal active substances in elderly patients of ≥ 60 years of age. In anxiety, depression, and dementia, they thus represent efficacious and well-tolerated alternatives to synthetic drugs.

Evidence-based, pharmacological treatment guideline for depression in Korea, revised edition

This paper aims to introduce, summarize, and emphasize the importance of the 'Evidence-Based, Pharmacological Treatment Guideline for Depression in Korea, Revised Edition'. The guideline broadly covers most aspects of the pharmacological treatment of patients in Korea diagnosed with moderate to severe major depression according to the DSM-IV TR. The guideline establishment process involved determining and answering a number of key questions, searching and selecting publications, evaluating recommendations, preparing guideline drafts, undergoing external expert reviews, and obtaining approval. A guideline adaptation process was conducted for the revised edition. The guideline strongly recommends pharmacological treatment considered appropriate to the current clinical situation in Korea, and should be considered helpful when selecting the appropriate pharmacological treatment of patients diagnosed with major depressive disorder. Therefore, the wide distribution of this guideline is recommended.

Efficacy versus effectiveness: a direct comparison of the outcome of treatment for mild to moderate depression in randomized controlled trials and daily practice

BACKGROUND

Results from randomized controlled trials (RCTs) are considered to give the most reliable information on treatment outcome (efficacy). Yet, the generalizability of efficacy results to daily practice (effectiveness) might be diminished by the design of RCTs. The STAR*D trial approached daily practice as much as possible, but still has some properties of an RCT. In this study, we compare results from treatment of major depressive disorder (MDD) in routine clinical practice to those of RCTs and STAR*D.

METHODS

Effectiveness in routine clinical practice was compared with efficacy results from 15 meta-analyses on antidepressant, psychotherapeutic and combination treatment and results from STAR*D. Data on daily practice patients and treatments were derived from a routine outcome monitoring (ROM) system. Treatment outcome was defined as proportion of remitters (MADRS ≤10) and within-group effect size.

RESULTS

From ROM, 598 patients suffering from a MDD episode according to the MINI-plus were included. Remission percentages were lower in routine practice than in meta-analyses for all treatment modalities (32 vs.40-74%). Differences were less explicit for antidepressants (21 vs. 34-47%) than for individual psychotherapy (27 vs. 34-58%; effect size 0.85 vs. 1.71) and combination therapy (21 vs. 45-63%), since only 60% of the meta-analyses for antidepressants showed significant differences with ROM, while for psychotherapy and combination treatment almost all meta-analyses showed significant differences. No differences in effectiveness were found between routine practice and STAR*D (antidepressants 27 vs. 28%; individual psychotherapy 27 vs. 25%; combination treatment 21 vs. 23%, respectively).

CONCLUSIONS

Effectiveness of treatment for mild-to-moderate MDD in daily practice is similar to STAR*D and significantly lower than efficacy results from RCTs.

Short-term individual housing induced social deficits in female Mongolian gerbils: attenuation by chronic but not acute imipramine

Mongolian gerbils are highly sensitive to manipulations of their social environments. Housing females individually for short periods (in the order of 7-21 days) has been shown to produce robust and reliable impairments of their subsequent social behaviour. These effects are typified by a marked reduction in the social investigation of an unfamiliar male in a neutral arena and/or a marked increases in levels of freezing whilst and only whilst they are being socially investigated (Immobile in contact). These responses demonstrate housing induced impaired motivation to socially interact. These effects have also been shown to be sensitive to treatment with chronic (but not acute) administration of the selective serotonin reuptake inhibitor (SSRI) fluoxetine. It was therefore of interest to know if similar effects would be produced by treatment with the tricyclic antidepressant Imipramine. This mixed NA/5-HT reuptake inhibitor first developed in the 1950's is a commonly used standard in animal models of depression and remains in clinical use today. Female gerbils were individually housed for 7 days or maintained in single-sex groups of 4 for the same period. All animals were then randomly allocated to be administered with either 0, 10 or 20 mg/kg imipramine. Acute administration did not reverse the social impairments produced by the individual housing but did produce non-specific stimulant effects on locomotion in both housing conditions. These social impairments were however reduced after a further 14 days chronic treatment with 10 or 20 mg/kg imipramine and stimulant effects were no longer seen. Following chronic administration in group-housed animals locomotor stimulation was replaced with sedation, which resulted in a reduction in social behaviour. That is, opposite to the effect seen in Individual housed animals. It is therefore concluded that chronic treatment with imipramine serves to increase social behaviour but only in those animals with a pre-existing social deficit.

Paroxetine: safety and tolerability issues

Paroxetine is a selective serotonin re-uptake inhibitor (SSRI) available in immediate release and controlled release (CR) formulations. Paroxetine is the most potent inhibitor of serotonin re-uptake among the now available SSRIs. Paroxetine has been approved for the treatment of major depressive disorder (MDD), obsessive-compulsive disorder, panic disorder (PD), generalised anxiety disorder, post traumatic stress disorder (PTSD), and social anxiety disorder (SAD) in adults, whereas paroxetine CR is approved for the treatment of MDD, SAD, PD and premenstrual dysphoric disorder in adults. The overall efficacy of paroxetine seems to be comparable to other SSRIs in the treatment of approved indications, although paroxetine treatment induces more sedation, constipation, sexual dysfunction, discontinuation syndrome and weight gain than other SSRIs. Recent data suggest that paroxetine treatment leads to increased rates of congenital malformations, although this evidence is not conclusive. Paroxetine and paroxetine CR are not indicated for use in the paediatric population and are categorised as Pregnancy Class D. In conclusion, whether the tolerability profile of paroxetine differs substantially from other new antidepressants (including other SSRIs) needs to be determined in adequately powered well-designed randomised controlled comparative clinical trials.

Efficacy and tolerability of milnacipran in the treatment of major depression in comparison with other antidepressants : a systematic review and meta-analysis

BACKGROUND

Milnacipran, a dual serotonin-noradrenaline reuptake inhibitor, is one of the newer antidepressants that clinicians use for the routine care of patients with major depression. We undertook a systematic review and meta-analysis of randomized controlled trials that compared the efficacy and tolerability of milnacipran with other antidepressants.

OBJECTIVE

To assess the efficacy and tolerability of milnacipran in comparison with TCAs, SSRIs and other drugs in the acute phase of treatment for major depression.

METHODS

We searched the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials registers, journals, conference proceedings, trial databases of the drug-approving agencies and ongoing clinical trial registers for all published and unpublished randomized controlled trials that compared the efficacy and adverse events of milnacipran versus any other antidepressant. The search was conducted in December 2006 and updated in May 2007. No language restrictions were applied. All relevant authors were contacted to supplement any incomplete reporting in the original papers. Randomized controlled trials comparing milnacipran with any other active antidepressants as monotherapy in the acute phase of treatment for major depression were selected. Participants were aged > or =18 years, of both sexes and with a primary diagnosis of unipolar major depression. Studies were excluded when the participants had specific psychiatric and medical co-morbidities. Two independent reviewers assessed the quality of trials for inclusion, and subsequently extracted data. Disagreements were resolved by consensus. Meta-analyses were conducted for efficacy and tolerability outcomes. Sixteen randomized controlled trials (n = 2277) were included in the meta-analyses.

RESULTS

No differences were found in achieving clinical improvement, remission or overall tolerability when comparing milnacipran with other antidepressants. However, compared with the TCAs, fewer patients taking milnacipran were early treatment withdrawals due to adverse events (number needed to harm (NNH) = 15; 95% CI 10, 48). Significantly more patients taking TCAs experienced adverse events compared with milnacipran (NNH = 4; 95% CI 3, 7).

CONCLUSIONS

The overall effectiveness and tolerability of milnacipran versus other antidepressants does not seem to differ in the acute phase of treatment for major depression. However, there is some evidence in favour of milnacipran over TCAs in terms of premature withdrawal due to adverse events and the rates of patients experiencing adverse events. Milnacipran may benefit some patient populations who experience adverse effects from other antidepressants in the acute phase of treatment for major depression.

Revised psychopharmacological algorithms for the treatment of mood disorders in Japan

Objective. To revise the psychopharmacology algorithms for the treatment of mood disorders published in 1999 in Japan. Methods. The algorithms were established based on clinical psychopharmacological evidence, the results of a questionnaire survey sent to 200 Japanese psychiatrists, and the consensus of all the research members. Results. Six categorized algorithms have been developed, i.e. mild or moderate major depression, severe non-psychotic major depression, psychotic depression, mania, bipolar depression, and rapid cycling mood disorder. Conclusion. The revised algorithms will be helpful for the treatment of mood disorders in Japan.

Paroxetine for somatic pain associated with physical illness: a review

OBJECTIVE

The purpose of this article is to review the prevalence of somatic pain with and without depression or anxiety and the pharmacologic effects of the selective serotonin reuptake inhibitor paroxetine on pain in physical conditions with and without comorbid depression or anxiety.

DATA SOURCES

MEDLINE and PsychLIT/PsycINFO database. Keywords included depression, anxiety, pain, somatic, antidepressants, and paroxetine. Only English-language publications and abstracts were considered.

STUDY SELECTION

More than 100 articles that reflected the prevalence of somatic pain in patients with physical illness with and without comorbid depression or anxiety and that evaluated the efficacy of antidepressants in this population were identified and reviewed.

DATA SYNTHESIS

Nearly two thirds of patients with major depressive disorder suffer from a physical illness, and about one fifth of patients with chronic physical illness are depressed. Both of these comorbidities pose diagnostic and therapeutic challenges. Therapeutic effects of antidepressants on pain improvement in patients with chronic physical illnesses and comorbid depression/anxiety have been attributed to the antidepressant or anxiolytic properties of these drugs. However, tricyclic antidepressants have demonstrated analgesic properties in patients with physical illness both with and without depression. The review looks at evidence for the efficacy of the selective serotonin reuptake inhibitor paroxetine on pain in physical illness with and without depression and the mechanisms for the relief of pain and depression.

CONCLUSIONS

The efficacy of paroxetine for depression and anxiety comorbid with physical illness looks promising. Studies also allude to evidence linking the analgesic properties of paroxetine with its serotonergic and noradrenergic activity. Large randomized controlled trials within specific antidepressant classes and also comparing dualaction antidepressants are warranted that could shed some light on the unique advantage of paroxetine over other antidepressants.

Comparing the effects of antidepressants: consensus guidelines for evaluating quantitative reviews of antidepressant efficacy

With increasing numbers of treatment options available for patients with major depression over the last decade and the growing body of evidence describing their efficacy and safety, clinicians often find it difficult to determine the best and most appropriate evidence-based treatment for each patient. Systematic reviews utilizing statistical methods that synthesize and evaluate data from a number of studies have become increasingly more available over the past decade. We review major findings and lessons learned from salient examples of quantitative analyses of antidepressant research and provide recommendations for meta-analysts, journal and grant reviewers, and research 'consumers' (ie, clinicians) for conducting, reporting, and evaluating such analyses.

A self-controlled, naturalistic study of selective serotonin reuptake inhibitors versus tricyclic antidepressants

OBJECTIVE

To compare the effectiveness of serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) for anxiety and mood disorders in a naturalistic setting.

METHODS

114 of 2,000 outpatients drawn from a private facility with a diagnosis of mood or anxiety disorder had two separate episodes during which they were treated once with a SSRI and once with a TCA. The drugs had to be in monotherapy and appropriate according to the recent guidelines. Key outcome measures included several rating scales, the results of which were combined into three measures of outcome: full response (no symptom), partial response (residual symptoms), poor response.

RESULTS

TCAs produced a better response in 63 cases and SSRIs in 18 cases (p < 0.00001). When the outcome was dichotomized, TCAs were still superior (stricter criterion of full response: p = 0.0002; lower threshold: p < 0.0001). Considering depressive and anxiety disorders separately, TCAs remained superior in terms of efficacy (for depression: p < 0.0001; for anxiety: p = 0.026). Moreover, the second episode of illness showed a better outcome than the first (p = 0.0008).

CONCLUSIONS

In those cases where two different antidepressants were prescribed over two different episodes of illness, TCAs were significantly more effective than SSRIs, regardless of the type of disorder and order of prescription.

Focus on paroxetine

This review of paroxetine is based on Medline and PsycLit searches and a manual search of the available research literature. It aims to cover the pharmacology of this frequently prescribed SSRI antidepressant in terms of its indications, efficacy and adverse effects. Overall, paroxetine is a well-tolerated and safe first-line SSRI antidepressant with anxiolytic qualities. It has been found useful in depression, anxiety and other conditions such as obsessive compulsive disorder and post-traumatic stress disorder. The antidepressant has some advantages over earlier tricyclic medication in terms of a lack of cardiovascular side-effects and relative safety in overdose. Cessation of use, however, is associated with withdrawal or discontinuation symptoms and patients should be counselled as to how these might be avoided. A 3- or 4-week graded withdrawal regimen, perhaps with concomitant fluoxetine to cover serotonergic discontinuation symptoms, may be advisable.

Spotlight on paroxetine in psychiatric disorders in adults

Paroxetine is a selective serotonin reuptake inhibitor (SSRI), with antidepressant and anxiolytic activity. In 6- to 24-week well designed trials, oral paroxetine 10 to 50 mg/day was significantly more effective than placebo, at least as effective as tricyclic antidepressants (TCAs) and as effective as other SSRIs and other antidepressants in the treatment of major depressive disorder. Relapse or recurrence over 1 year after the initial response was significantly lower with paroxetine 10 to 50 mg/day than with placebo and similar to that with imipramine 50 to 275 mg/day. The efficacy of paroxetine 10 to 40 mg/day was similar to that of TCAs and fluoxetine 20 to 60 mg/day in 6- to 12-week trials in patients aged > or = 60 years with major depression. Paroxetine 10 to 40 mg/day improved depressive symptoms to an extent similar to that of TCAs in patients with comorbid illness, and was more effective than placebo in the treatment of dysthymia and minor depression. Paroxetine 20 to 60 mg/day was more effective than placebo after 8 to 12 weeks' treatment of obsessive-compulsive disorder (OCD), panic disorder, social anxiety disorder (social phobia), generalised anxiety disorder (GAD) and post-traumatic stress disorder (PTSD). Improvement was maintained or relapse was prevented for 24 weeks to 1 year in patients with OCD, panic disorder, social anxiety disorder or GAD. The efficacy of paroxetine was similar to that of other SSRIs in patients with OCD and panic disorder and similar to that of imipramine but greater than that of 2'chlordesmethyldiazepam in patients with GAD. Paroxetine is generally well tolerated in adults, elderly individuals and patients with comorbid illness, with a tolerability profile similar to that of other SSRIs. The most common adverse events with paroxetine were nausea, sexual dysfunction, somnolence, asthenia, headache, constipation, dizziness, sweating, tremor and decreased appetite. In conclusion, paroxetine, in common with other SSRIs, is generally better tolerated than TCAs and is a first-line treatment option for major depressive disorder, dysthymia or minor depression. Like other SSRIs, paroxetine is also an appropriate first-line therapy for OCD, panic disorder, social anxiety disorder, GAD and PTSD. Notably, paroxetine is the only SSRI currently approved for the treatment of social anxiety disorder and GAD, which makes it the only drug of its class indicated for all five anxiety disorders in addition to major depressive disorder. Thus, given the high degree of psychiatric comorbidity of depression and anxiety, paroxetine is an important first-line option for the treatment of major depressive disorder, OCD, panic disorder, social anxiety disorder, GAD and PTSD.

Paroxetine for the treatment of interferon-alpha-induced depression in chronic hepatitis C

BACKGROUND

Psychiatric side-effects may require dose reduction or premature discontinuation of interferon therapy in chronic hepatitis C. New strategies are needed in order to prevent the premature termination of interferon therapy.

AIM

To evaluate prospectively the efficacy and tolerability of antidepressant therapy (paroxetine, a selective serotonin reuptake inhibitor) in patients with chronic hepatitis C treated with interferon-alpha who have developed interferon-induced major depression.

METHODS

A sub-group of 14 individuals from 121 consecutively treated hepatitis C patients developed substance-induced major depression without suicidal ideation during interferon-alpha treatment. The individuals in this sub-group received paroxetine after the occurrence of depression (20 mg daily until termination of interferon therapy). Diagnostic scores for depression (and anger-hostility) were obtained in a repeated measures design (Hospital Anxiety and Depression Scale and Symptom Checklist 90 Items Revised).

RESULTS

Eleven of the 14 patients (78.6%) with interferon-induced major depression were able to complete interferon-alpha therapy as scheduled under concomitant paroxetine treatment (three dropouts: insufficient improvement of depression, occurrence of epileptic seizures, paroxetine-induced nausea/dizziness). Within 4 weeks after the start of paroxetine medication, depression scores declined significantly in all patients.

CONCLUSIONS

Our data suggest that concomitant therapy with paroxetine is an effective way to treat interferon-induced depression in patients with chronic hepatitis C.

Paroxetine: an update of its use in psychiatric disorders in adults

Paroxetine is a selective serotonin reuptake inhibitor (SSRI), with antidepressant and anxiolytic activity. In 6- to 24-week well designed trials, oral paroxetine 10 to 50 mg/day was significantly more effective than placebo, at least as effective as tricyclic antidepressants (TCAs) and as effective as other SSRIs and other antidepressants in the treatment of major depressive disorder. Relapse or recurrence over 1 year after the initial response was significantly lower with paroxetine 10 to 50 mg/day than with placebo and similar to that with imipramine 50 to 275 mg/day. The efficacy of paroxetine 10 to 40 mg/day was similar to that of TCAs and fluoxetine 20 to 60 mg/day in 6- to 12-week trials in patients aged > or =60 years with major depression. Paroxetine 10 to 40 mg/day improved depressive symptoms to an extent similar to that of TCAs in patients with comorbid illness, and was more effective than placebo in the treatment of dysthymia and minor depression. Paroxetine 20 to 60 mg/day was more effective than placebo after 8 to 12 weeks' treatment of obsessive-compulsive disorder (OCD), panic disorder, social anxiety disorder (social phobia), generalised anxiety disorder (GAD) and post-traumatic stress disorder (PTSD). Improvement was maintained or relapse was prevented for 24 weeks to 1 year in patients with OCD, panic disorder, social anxiety disorder or GAD. The efficacy of paroxetine was similar to that of other SSRIs in patients with OCD and panic disorder and similar to that of imipramine but greater than that of 2'chlordesmethyldiazepam in patients with GAD. Paroxetine is generally well tolerated in adults, elderly individuals and patients with comorbid illness, with a tolerability profile similar to that of other SSRIs. The most common adverse events with paroxetine were nausea, sexual dysfunction, somnolence, asthenia, headache, constipation, dizziness, sweating, tremor and decreased appetite. In conclusion, paroxetine, in common with other SSRIs, is generally better tolerated than TCAs and is a first-line treatment option for major depressive disorder, dysthymia or minor depression. Like other SSRIs, paroxetine is also an appropriate first-line therapy for OCD, panic disorder, social anxiety disorder, GAD and PTSD. Notably, paroxetine is the only SSRI currently approved for the treatment of social anxiety disorder and GAD, which makes it the only drug of its class indicated for all five anxiety disorders in addition to major depressive disorder. Thus, given the high degree of psychiatric comorbidity of depression and anxiety, paroxetine is an important first-line option for the treatment of major depressive disorder, OCD, panic disorder, social anxiety disorder, GAD and PTSD.

Efficacy and safety of amisulpride 50 mg versus paroxetine 20 mg in major depression: a randomized, double-blind, parallel group study

The efficacy of amisulpride in depressive disorders has been demonstrated in dysthymia and in double depression. Limited data are available in major depression. A randomized, double-blind, parallel group, multicentre study was set up to compare the efficacy and tolerability of amisulpride (50 mg o.d.) and paroxetine (20 mg o.d.) for 8 weeks in 272 patients with major depression (DSM-IV and baseline Hamilton Depression Rating Scale (HAMD) score > or = 18). The study was designed as a non-inferiority trial based on the proportion of responders (> or = 50% decrease in HAMD total score) at end-point, with a maximal allowable difference of 15%; secondary end-points included HAMD total and cluster scores, Montgomery and Asberg Depression Rating Scale score and responders rates and Clinical Global Impression improvement. The tolerability evaluation was based on incidence of adverse events and routine laboratory tests. The results did not disclose statistically significant differences between treatments, although the hypothesis of an efficacy difference between the two treatments within the set limit at day 56 could not be accepted. The issue of non-inferiority trials is discussed.