The efficacy and tolerability of venlafaxine and paroxetine in outpatients with depressive disorder or dysthymia

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.

Network Meta-Analysis and Cost-Effectiveness Analysis of New Generation Antidepressants

BACKGROUND

Major depressive disorder (MDD) impacts health, quality of life and workplace productivity. Antidepressant treatment is the primary therapeutic intervention. This study assessed the efficacy and tolerability of new generation antidepressants and their cost-effectiveness in the Singapore healthcare system.

METHODS

We conducted a systematic search for head-to-head randomised controlled trials on ten antidepressants (agomelatine, duloxetine, escitalopram, fluvoxamine, fluoxetine, mirtazapine, paroxetine, sertraline, trazodone and venlafaxine) employed as monotherapy in acute MDD management. We performed a network meta-analysis to compare their relative efficacy. The outcome measures for efficacy were response and remission rate, and mean change in Hamilton Depression Rating Scale (HDRS) score; and for tolerability, study withdrawal rates due to adverse events. To evaluate their relative cost effectiveness, a decision tree simulating a cohort of MDD patients using antidepressant as monotherapy was constructed from a societal perspective over 6 months. We used effectiveness data from our network meta-analysis and local data on resource use for depression in Singapore. The incremental cost expected for each additional quality-adjusted life-year (QALY) gained was calculated and presented as the incremental cost-effectiveness ratio (ICER).

RESULTS

We identified 76 relevant articles for the network meta-analysis. Of the ten agents included in the analysis, mirtazapine and agomelatine were most efficacious in achieving response and remission, respectively. Mirtazapine and duloxetine resulted in the greatest magnitude of change in the HDRS score. Agomelatine, escitalopram and sertraline were the best tolerated of the drugs analysed, while duloxetine was the least well tolerated drug. Using a composite outcome of efficacy (response and remission rates) and tolerability, agomelatine, escitalopram and mirtazapine were the favoured treatments. In the cost-effectiveness analysis, apart from agomelatine, all the treatments were dominated by mirtazapine. Against mirtazapine, agomelatine was not cost effective given that its ICER exceeded the threshold value.

CONCLUSION

Agomelatine, escitalopram and mirtazapine had favourable balance between efficacy and tolerability. In addition, mirtazapine was a cost-effective option in the Singapore healthcare system.

Paroxetine in the treatment of dysthymic disorder without co-morbidities: A double-blind, placebo-controlled, flexible-dose study

Few published studies have evaluated selective serotonin reuptake inhibitors in dysthymia without current co-morbid major depression. In this 12-week study, 40 dysthymic patients were randomly assigned to either placebo (n=19) or 20-40 mg/day of paroxetine (n=21). At endpoint, the paroxetine group showed significantly greater improvement on the Clinical Global Impression Scale, Beck Depression Inventory, and Quality of Life Enjoyment and Satisfaction Questionnaire (p<0.05), and a trend to superiority over placebo on the Hamilton Depression Rating Scale. Response and remission were significantly higher with paroxetine than placebo (p<0.05). There were no significant differences in drop out rates or frequency of adverse effects, except for excessive sweating (greater with paroxetine, p=0.04). Reporting of multiple side effects was also higher with paroxetine than with placebo (p=0.02). Paroxetine is more effective than placebo in improving symptoms and quality of life in dysthymia, and is generally tolerable.

Time to discontinuation among the three second-generation antidepressants in a naturalistic outpatient setting of depression

AIM

This study compared the discontinuation time among the three second-generation antidepressants (paroxetine, venlafaxine, and mirtazapine) in a naturalistic setting for outpatient treatment of depression.

METHODS

This study used data from retrospectively reviewed medical records of patients admitted to an outpatient psychiatric clinic between January 2003 and December 2005. Patient groups (paroxetine-, venlafaxine-, and mirtazapine-treated) were compared with each other with regard to their discontinuation times for a 6-month period after treatment initiation. The data were analyzed, using a Kaplan-Meier survival analysis, and a Cox proportional hazards regression model.

RESULTS

There were no significant differences in discontinuation times among the three second-generation antidepressants during the 6-month period after initiation of drug therapy.

CONCLUSIONS

In a naturalistic setting for the care of depression, it seems that there are no differences in discontinuation times among these three second-generation antidepressants.

NMDA receptor/nitrergic system blockage augments antidepressant-like effects of paroxetine in the mouse forced swimming test

OBJECTIVE

In this study, we evaluated the involvement of N-methyl-D-aspartate receptor (NMDAR)/nitric oxide (NO) system on the antidepressant-like effects of paroxetine in the mouse forced swimming test.

METHOD

Swim sessions were conducted by placing mice in individual glass cylinders filled with water for 6 min. The duration of behavioral immobility during the last 4 min of the test was evaluated.

RESULTS

Paroxetine (8 and 16 mg/kg, intraperitoneal [i.p.]) significantly reduced the immobility times of mice, whereas lower doses (2 and 4 mg/kg) had no effect. NMDA antagonists MK-801 (0.1 and 0.25 mg/kg, i.p.) and ifenprodil (1 and 3 mg/kg, i.p.) and the NO synthase inhibitor NG-L-arginine methyl ester (L-NAME; 30 and 100 mg/kg, i.p.) significantly decreased the immobility time. Lower doses of MK-801 (0.01 and 0.05 mg/kg), ifenprodil (0.1 and 0.5 mg/kg), and L-NAME (10 mg/kg) had no effect. Combined treatment of subeffective doses of paroxetine (4 mg/kg) and MK-801 (0.05 mg/kg), ifenprodil (0.5 mg/kg), and L-NAME (10 mg/kg) robustly exerted an antidepressant-like effect. The noneffective dose of a NO precursor L: -arginine (750 mg/kg, i.p.) prevented the antidepressant-like effect of paroxetine (30 mg/kg).

CONCLUSION

We suggested, for the first time, a possible role for NMDAR/NO signaling in the antidepressant-like effects of paroxetine, providing a new approach for the treatment of depression.

Differential effects of venlafaxine in the treatment of major depressive disorder according to baseline severity

In this meta-analysis, we compare the relative efficacy of venlafaxine to selective serotonin reuptake inhibitors (SSRIs) in patients with major depressive disorder classified according to baseline disease severity. Data from 31 double-blind randomised clinical trials comparing venlafaxine and SSRIs (intent-to-treat n = 6,492) were pooled. For this secondary analysis, patients were stratified into groups based on baseline HAM-D(17) total score (>or=30, <30, >or=25, and <25). Remission rates (HAM-D(17) < 8) were analyzed for each subgroup using Fisher's exact test to compare treatment effects between venlafaxine and SSRIs; last observation carried forward (LOCF) and observed cases (OC) data were analyzed. The number needed to treat (NNT) to benefit was determined for each analysis. Statistically significant remission rate differences, favoring venlafaxine, were seen in LOCF and OC analyses for each subgroup. In patients with baseline HAM-D(17) < 25 (n = 3,928) the differences were (LOCF) 7.3 [P < 0.001; NNT = 14] and (OC) 6.2 [P = 0.003; NNT = 16], and in patients with baseline HAM-D(17) >or= 25 (n = 2,564) were (LOCF) 5.7 [P = 0.002; NNT = 17] and (OC) 6.7 [P = 0.009; NNT = 15]. In patients with baseline HAM-D(17) < 30 (n = 5,836) the differences were (LOCF) 6.4 [P < 0.001; NNT = 16] and (OC) 5.5 [P = 0.001; NNT = 18], and in patients with baseline HAM-D(17) >or= 30 (n = 656) were (LOCF) 8.9 [P = 0.015; NNT = 11] and (OC) 14.8 [P = 0.003; NNT = 7]. In conclusion, these analyses demonstrate that venlafaxine may be superior to SSRIs in achieving remission in both mild/moderate and severely depressed patients. The greater difference in remission rates among patients with baseline HAM-D(17) >or= 30 suggests a more pronounced clinical benefit that may be achieved with venlafaxine in severely depressed patients.

The effect of venlafaxine compared with other antidepressants and placebo in the treatment of major depression: a meta-analysis

OBJECTIVE

Meta-analysis of all available trials of Venlafaxine in the treatment of major depressive disorders, including treatment resistant depression and long-term relapse prevention.

METHODS

We conducted a meta-analysis comparing venlafaxine and tricyclics, or selective serotonin reuptake inhibitors (SSRIs), in major depression. We also included trials comparing venlafaxine and alternative antidepressants in subjects with treatment resistant depression, or compared with placebo in long-term relapse prevention. Trials were identified through searches of Medline, Embase, Cochrane Library and through accessing unpublished trials held by the manufacturer. Results based on intention to treat analyses where available, were pooled using theoretically exact conditional maximum likelihood methods for fixed effects (primary analyses), and numerical simulation using a Gibbs sampler for full random effects.

RESULTS

Compared to all SSRIs for the treatment of major depression (fluoxetine, paroxetine, sertraline, citalopram, escitalopram and fluvoxamine), venlafaxine was associated with a greater response [odds ratio 1.15 (95% CI 1.02-1.29)] and remission [odds ratio 1.19 (95% CI 1.06-1.34)]. Overall drop out rates appeared similar for SSRIs and venlafaxine. Compared to tricyclics, response to venlafaxine was estimated to be greater by exact method, odds ratio 1.21 (95% CI 1.03-1.43), but not statistically significantly different, using a full random effects method odds ratio 1.22 (95% CI 0.96-1.54). We observed no difference in remission rates (odds ratio 1.06 (95% CI 0.74-1.63)). Tricyclics were less well tolerated with higher overall drop out rates. Compared to alternative antidepressants in treatment resistant depression (trials included comparison with sertraline, bupropion, fluoxetine, citalopram, and one with a range of agents-mostly SSRIs), the odds ratio for response was 1.35 (95% CI 1.19-1.54). The odds ratio for remission was 1.35 (95% CI 1.20-1.52). Compared to placebo the odds ratio for relapse prevention with venlafaxine was 0.37 (95% CI 0.27-0.51).

CONCLUSION

This meta analysis provides evidence of the clinical efficacy of venlafaxine in achieving therapeutic response and remission in patients with major depression. Venlafaxine appears more effective than SSRIs, and at least as effective as tricyclic antidepressants, in the treatment of major depressive episode. Venlafaxine appeared more effective than comparators in treatment resistant depression. In addition, venlafaxine effective in reducing relapse when given long term after major depressive episode.

Are there differences between serotonergic, noradrenergic and dual acting antidepressants in the treatment of depressed women?

BACKGROUND

This study aims to investigate if there is a differential outcome of serotonergic and noradrenergic antidepressant treatment and if menopausal status has an impact on antidepressant response in depressed women.

METHODS

Data of the 111 depressed women who were included and completed the previous four open-label studies where patients were evaluated six times during a 10-week period, were pooled in the current study. Each of the reboxetine, sertraline and venlafaxine groups consisted of 37 depressed women. Patients were also divided into two subgroups of age, determining the 44 years as the cut-off point representing the menopausal status.

RESULTS

No significant difference was observed in the percent change of Hamilton Depression Rating Scale-17 (HDRS) and remission rates among treatment groups. Percent changes in Clinical Global Impression-Severity of Illness scale (CGI-S) and response rates were in favour of venlafaxine group at week 10. Individual HDRS items 2, 3, 4, 5 and 6 demonstrated significant improvement in the sertraline group, whereas HDRS item 7 demonstrated significant improvement in the venlafaxine group. An early reduction in anxiety subscale was observed in the venlafaxine group. Menopausal status had no impact on the outcome measures.

CONCLUSIONS

These results suggest that noradrenergic and serotonergic activity do not differ from each other in treating depressed women. However, serotonergic activity appears to be more prominent in some particular symptoms such as feelings of guilt, suicidal ideation and sleep. Also, menopause does not appear to affect antidepressants' benefit in depressed women.

Estimates of serotonin and norepinephrine transporter inhibition in depressed patients treated with paroxetine or venlafaxine

Paroxetine and venlafaxine are potent serotonin transporter (SERT) antagonists and weaker norepinephrine transporter (NET) antagonists. However, the relative magnitude of effect at each of these sites during treatment is unknown. Using a novel blood assay that estimates CNS transporter occupancy we estimated the relative SERT and NET occupancy of paroxetine and venlafaxine in human subjects to assess the relative magnitude of SERT and NET inhibition. Outpatient subjects (N=86) meeting criteria for major depression were enrolled in a multicenter, 8 week, randomized, double-blind, parallel group, antidepressant treatment study. Subjects were treated by forced-titration of paroxetine CR (12.5-75 mg/day) or venlafaxine XR (75-375 mg/day) over 8 weeks. Blood samples were collected weekly to estimate transporter inhibition. Both medications produced dose-dependent inhibition of the SERT and NET. Maximal SERT inhibition at week 8 for paroxetine and venlafaxine was 90% (SD 7) and 85% (SD 10), respectively. Maximal NET inhibition for paroxetine and venlafaxine at week 8 was 36% (SD 19) and 60% (SD 13), respectively. The adjusted mean change from baseline (mean 28.6) at week 8 LOCF in MADRS total score was -16.7 (SE 8.59) and -17.3 (SE 8.99) for the paroxetine and venlafaxine-treated patients, respectively. The magnitudes of the antidepressant effects were not significantly different from each other (95%CI -3.42, 4.54, p=0.784). The results clearly demonstrate that paroxetine and venlafaxine are potent SERT antagonists and less potent NET antagonists in vivo. NET antagonism has been posited to contribute to the antidepressant effects of these compounds. The clinical significance of the magnitude of NET antagonism by both medications remains unclear at present.

Effects of various antidepressants on serum thyroid hormone levels in patients with major depressive disorder

A total of 62 patients with major depressive disorder were analyzed in the study. Patients were evaluated for 11 weeks in an open label design to investigate the differential effects of reboxetine, sertraline and venlafaxine on thyroid hormones. Serum thyrotrophin (TSH), thyroxine (T4) and free (f)T4 levels were measured before and after treatment. All groups showed significant improvement in HAM-D scores. TSH level significantly reduced and T4 level significantly increased in the reboxetine group, however TSH level significantly increased and T4 level significantly reduced in the sertraline group. Percent changes of TSH (p=0.007) and T4 (p=0.001) were significantly different between the reboxetine and sertraline groups. In the sertraline group, baseline TSH levels were correlated with response to treatment as determined by the change in HAM-D scores (p=0.03, r=0.648). There was a significant association between the percent changes in TSH values and the reduction in HAM-D scores in the reboxetine group (p=0.03, r=-0.434). In the whole study group, female patients had lower values of basal T4 compared with men (p=0.043), however percent changes of T4 did not differ between genders. In the treatment-responders significant increase in the reboxetine group and significant decrease in the sertraline group regarding the T4 values were found. We observed that various antidepressants had different effects on thyroid hormone levels and this could be attributed to the different mechanisms of actions of these antidepressants.

Re-evaluation of the efficacy and tolerability of venlafaxine vs SSRI: meta-analysis

RATIONALE

A number of reviews have claimed that the selective serotonin and noradrenalin re-uptake inhibitor venlafaxine is more effective than selective serotonin re-uptake inhibitors (SSRIs) in achieving remission and symptom reduction in major depression.

OBJECTIVES

The aim of this study was to systematically review studies on the efficacy of venlafaxine vs SSRI and to evaluate the influence of methodological issues on the effect sizes.

MATERIALS AND METHODS

Following a systematic literature search, we pooled data on depression scores, response, remission and dropout rates. We also performed sub-group analyses.

RESULTS

Seventeen studies were included. We found no significant superiority in remission rates (risk ratio [RR] = 1.07, 95% confidence intervals [95%CI] = 0.99 to 1.15, numbers needed to treat [NNT] = 34) and a small superiority in response rates (RR = 1.06, 95%CI = 1.01 to 1.12, NNT = 27) over SSRIs. There was a small advantage to venlafaxine in change scores (effect size = -0.09, 95%CI = -0.16 to -0.02, p = 0.013), which did not reach significance when post-treatment scores were used (effect size = -0.06, 95%CI = -0.13 to 0.00). Discontinuation rates due to adverse events were 45% higher in the venlafaxine group. The main reasons for the differences between this analysis and previous reviews were the exclusion of studies with methodological limitations, avoiding to pool selectively reported study results and exclusion of studies available as abstracts only.

CONCLUSIONS

Our analysis does not support a clinically significant superiority of venlafaxine over SSRIs. Differences between our study and previous reviews were not accounted for by technical aspects of data synthesis, but rather by study selection and choice of outcome parameters.

Comprehensive analysis of remission (COMPARE) with venlafaxine versus SSRIs

BACKGROUND

To compare venlafaxine and selective serotonin reuptake inhibitors (SSRIs; fluoxetine, sertraline, paroxetine, fluvoxamine, and citalopram) in the treatment of depression.

METHODS AND MATERIALS

Meta-analysis of 34 randomized, double-blind studies identified by a worldwide search of all research sponsored by Wyeth Pharmaceuticals through January 2007. Patients were treated with venlafaxine (n = 4191; mean dose 151 mg/day) or SSRIs (n = 3621); nine studies also included a placebo control group (n = 932). The primary outcome measure was intent-to-treat (ITT) remission rates (Hamilton Rating Scale for Depression </=7) at week 8.

RESULTS

The overall difference in ITT remission rates was 5.9% favoring venlafaxine (95% confidence interval [CI]: .038-.081; p < .001). Based on this difference, the number needed to treat (NNT) to benefit is 17 (95% CI: 12-26). In the nine placebo controlled studies, the drug-placebo differences were 6% (.02-.09) for the SSRIs and 13% (.09-.16) for venlafaxine. For the specific SSRIs, the difference versus fluoxetine (mean dose = 37 mg/day; 20 studies) was significant (6.6% [95% CI: .030-.095]); smaller differences versus paroxetine (mean dose = 25 mg/day; eight studies; 5%), sertraline (mean dose = 127 mg/day; three studies; 3%), and citalopram (mean dose = 38 mg/day; two studies; 4%) were not significant. Attrition rates due to adverse events were higher with venlafaxine than with SSRI therapy, 11% and 9% respectively (p = .0011).

CONCLUSIONS

These results indicate that venlafaxine therapy is statistically superior to SSRIs as a class, but only to fluoxetine individually. The clinical significance of this modest advantage seems limited for the broad grouping of major depressive disorder. Nonetheless, an NNT of 17 may be of public health relevance given the large number of patients treated for depression and the significant burden of illness associated with this disorder.

Efficacy of bupropion and the selective serotonin reuptake inhibitors in the treatment of anxiety symptoms in major depressive disorder: a meta-analysis of individual patient data from 10 double-blind, randomized clinical trials

The goal of this work was to compare the efficacy of the norepinephrine-dopamine reuptake inhibitor bupropion with the selective serotonin reuptake inhibitors (SSRIs) in the treatment of anxiety symptoms in major depressive disorder (MDD). Ten double-blind, randomized studies, involving a total of 2890 bupropion-, SSRI- or placebo- treated patients were pooled. Anxiety symptoms of depression were defined using the Hamilton depression rating scale (HDRS) Anxiety-Somatization factor (HDRS-AS) score, as well as the Hamilton anxiety scale (HAM-A) score. Both bupropion and the SSRIs led to a comparable degree of improvement in anxiety symptoms, defined using the HDRS-AS score (-3.8+/-2.8 vs. -3.9+/-2.8, p=0.130) or HAM-A score (-8.8+/-7.2 vs. -9.1+/-7.0, p=0.177). There was no consistent difference in the time to anxiolysis between the two treatment groups. In addition, there was no difference in the proportion of bupropion- and SSRI- remitters who continued to experience residual anxiety, defined as a HDRS-AS score >0 at endpoint (69.2% vs. 74.7%, p=0.081) or a HAM-A score >7 at endpoint (9.5% vs. 8.4%, p=0.284). Finally, there was no statistically significant difference in the severity of residual anxiety symptoms between bupropion- or SSRI- treated patients with remitted depression, defined using the HDRS-AS (1.15+/-1.14 vs. 1.25+/-1.09, p=0.569), or HAM-A scores at endpoint (3.30+/-2.89 vs. 3.31+/-2.89, p=0.552). Contrary to clinician impression, there does not appear to be any difference in the anxiolytic efficacy of bupropion and the SSRIs when used to treat MDD.

Are antidepressant drugs that combine serotonergic and noradrenergic mechanisms of action more effective than the selective serotonin reuptake inhibitors in treating major depressive disorder? A meta-analysis of studies of newer agents

BACKGROUND

Recent studies suggest that the treatment of major depressive disorder (MDD) with newer antidepressant drugs that simultaneously enhance norepinephrine and serotonin neurotransmission might result in higher response and remission rates than the selective serotonin reuptake inhibitors (SSRIs). The goal of our work was to compare response rates among patients with MDD treated with either of these two broad categories of antidepressant drugs.

METHODS

Medline/Pubmed, EMBase, clinical trial registries, program syllabi from major psychiatric meetings held since 1995, and documents from relevant pharmaceutical companies were searched for double-blind, randomized trials comparing a newer serotonergic-noradrenergic antidepressant drug (venlafaxine, duloxetine, milnacipran, mirtazapine, mianserin, or moclobemide) with an SSRI for MDD.

RESULTS

Ninety-three trials (n = 17,036) were combined using a random-effects model. Treatment with serotonergic + noradrenergic antidepressant drugs was more likely to result in clinical response than the SSRIs (risk ratio [RR] = 1.059; response rates 63.6% versus 59.3%; p = .003). There was no evidence for heterogeneity among studies combined (p = 1.0). Excluding each individual agent did not significantly alter the pooled RR. With the exception of duloxetine (.985), RRs for response for each individual serotonergic + noradrenergic antidepressant drug were within the 95% confidence interval of the pooled RR (1.019-1.101).

CONCLUSIONS

Serotonergic-noradrenergic antidepressant drugs seem to have a modest efficacy advantage compared with SSRIs in MDD. With the Number Needed to Treat (NNT) statistic as one indicator of clinical significance, nearly 24 patients would need to be treated with dual-action antidepressant drugs instead of SSRIs in order to obtain one additional responder. This difference falls well below the mark of NNT = 10 suggested by the United Kingdom's National Institute of Clinical Excellence but nonetheless might be of public health relevance given the large number of depressed patients treated with SSRI /serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressant drugs. Further research is needed to examine whether larger differences between classes of antidepressant drugs might exist in specific MDD sub-populations or for specific MDD symptoms.

A randomized, single-blind, comparison of venlafaxine with paroxetine in elderly patients suffering from resistant depression

It is estimated that up to 45% of patients with depression do not have an adequate response to a first trial of antidepressant therapy with even higher reported rates for the elderly patients. To compare the efficacy and the tolerability of venlafaxine vs. paroxetine in elderly patients suffering from resistant major depression, who did not respond to at least two previous adequate trials of antidepressants. Patients entered an 8-week single-blind study. Patients were rated using the Clinical Global Impression Scale, Hamilton Rating Scale for Depression, and the Geriatric Depression Scale. Assessments were performed at baseline and on days 7, 14, 21, 28, 42 and 56. Side effects were recorded in a systemic manner. Thirty patients were included in the study, (17 women, 13 men; mean age=75.9 years, range: 68-83) and all had completed the 6-week trial. Mean dose of venlafaxine used was 165 mg/day (SD=73.8; range 75-300 mg). Mean dose of paroxetine used was 26 mg/day (SD=15.04; range 10-60 mg). Nine patients treated with venlafaxine (60%) and five patients treated with paroxetine (33%) remitted after 8 weeks of treatment. Four patients treated with venlafaxine and eight patients treated with paroxetine failed to respond. Significant improvement in Hamilton Rating Scale for Depression scores between baseline and endpoint were observed in both groups of patients. The mean Hamilton Rating Scale for Depression change for paroxetine was -12.5 and for venlafaxine -19.1 (P<0.05). The mean Geriatric Depression Scale change for paroxetine was -3.2 and for venlafaxine -6.0 (P<0.3). The mean Clinical Global Impression Scale change was -2.3 for paroxetine and -3.5 for venlafaxine (P<0.05). Venlafaxine was significantly superior to paroxetine on Clinical Global Impression Scale and Hamilton Rating Scale for Depression measures. Side effects were transient and did not differ between treatment groups. Elderly depressed patients resistant to previous treatments had responded to a trial of paroxetine or venlafaxine. Remission rates were higher for venlafaxine and tolerability was acceptable for both compounds.

Venlafaxine vs. paroxetine in the acute phase of treatment for major depressive disorder among Han Chinese population in Taiwan

PURPOSE

Clinical studies have suggested that venlafaxine induces a higher remission rate than paroxetine. However, very few studies have evaluated relapse episodes over treatment periods longer than a few weeks, and the cut-off score of 7 on the Hamilton Rating Scale for Depression (HRSD) often used to define remission is too high. This score is associated with the high rates of social function impairment. We report on a single centre, open-label, prospective 24-week study to investigate the comparative efficacy of acute treatments with venlafaxine and paroxetine, using different definitions of response and remission rates.

METHODS

Outpatients satisfying DSM-IV criteria for major depression with a baseline HRSD17 score of at least 16 were eligible. Following baseline evaluations, the patients were assigned to receive venlafaxine 75-225 mg/day with the mean dosage 141.35 +/- 26.98 (SD) mg/day (n = 78), or paroxetine 20 mg/day (n = 92) for 24 weeks. Efficacy was assessed using the mean change in HRSD(17) score from baseline, the response rate and the remission rates based on different criteria for remission (HRSD(17) score < or = 7 or 5).

RESULTS

One hundred and seventy patients were evaluated for efficacy; 78 treated with venlafaxine and 92 with paroxetine. Over the treatment period, venlafaxine was comparable with paroxetine on most outcome measures, whereas paroxetine produced significantly higher remission rates at weeks 4, 8, 16, 20 and 24 weeks when the lower cutoff of 5 was used.

CONCLUSIONS

Venlafaxine treatment was similar to paroxetine according to the typical efficacy measures for treating outpatients with major depression. However, based on the stricter remission criterion, paroxetine might be superior to venlafaxine.

Remission, dropouts, and adverse drug reaction rates in major depressive disorder: a meta-analysis of head-to-head trials

OBJECTIVE

To summarize remission rates and dropouts due to adverse drug reactions (ADRs) or lack of efficacy (LoE) of serotonin-norepinephrine reuptake inhibitors (SNRIs), selective serotonin-reuptake inhibitors (SSRIs), and tricyclic antidepressants (TCAs) in treating major depressive disorder.

METHODS

We searched MEDLINE, EMBASE, IPA, and the Cochrane International Library from 1980-2005. Meta-analysis summarized outcomes from head-to-head randomized clinical trials comparing >or= 2 drugs from three antidepressants classes (SNRIs, and/or SSRIs, and/or TCAs) followed by >or= 6 weeks of treatment. Remission was a final Hamilton Depression Rating Scale (HAMD) score <or= 7 or Montgomery-Asberg Depression Rating Scale (MADRS) <or= 12. Intent-to-treat data were combined across study arms using random effects models, producing point estimates with 95% confidence intervals.

RESULTS

We obtained data from 30 arms of 15 head-to-head trials with 2458 patients. SNRIs had the highest ITT remission rate (49.0%), then TCAs (44.1%), and SSRIs (37.7%) (p > 0.05 for SNRIs versus TCAs; p < 0.001 for TCAs versus SSRIs and SNRIs versus SSRIs). When categorized as inpatients (n = 582) and outpatients (n = 1613), SNRIs had the highest remission rates (52.0% for 144 inpatients and 49.3% for 559 outpatients). SNRIs had lowest overall dropouts (26.1%), followed by SSRIs (28.4%), and TCAs (35.7%). Dropouts due to ADRs and LoE were 10.3% and 6.2% for SNRIs, 8.3% and 7.2% for SSRIs, and 19.8% and 9.9% for TCAs, respectively (p > 0.05 for ADR dropouts only). One limitation was the inclusion of only venlafaxine-XR; results may not be the same for immediate release forms. In addition, few studies reported remission rates.

CONCLUSIONS

SNRIs had the highest efficacy remission rates (statistically significant for inpatients and outpatients), and the lowest overall dropout rates, suggesting clinical superiority in treating major depression.

Tolerability and safety of fluvoxamine and other antidepressants

Selective serotonin [5-hydroxytryptamine (5-HT)] reuptake inhibitors (SSRIs) and the 5-HT noradrenaline reuptake inhibitor, venlafaxine, are mainstays in treatment for depression. The highly specific actions of SSRIs of enhancing serotonergic neurotransmission appears to explain their benefit, while lack of direct actions on other neurotransmitter systems is responsible for their superior safety profile compared with tricyclic antidepressants. Although SSRIs (and venlafaxine) have similar adverse effects, certain differences are emerging. Fluvoxamine may have fewer effects on sexual dysfunction and sleep pattern. SSRIs have a cardiovascular safety profile superior to that of tricyclic antidepressants for patients with cardiovascular disease; fluvoxamine is safe in patients with cardiovascular disease and in the elderly. A discontinuation syndrome may develop upon abrupt SSRI cessation. SSRIs are more tolerable than tricyclic antidepressants in overdose, and there is no conclusive evidence to suggest that they are associated with an increased risk of suicide. Although the literature suggests that there are no clinically significant differences in efficacy amongst SSRIs, treatment decisions need to be based on considerations such as patient acceptability, response history and toxicity.

Discontinuation rates for selective serotonin reuptake inhibitors and other second-generation antidepressants in outpatients with major depressive disorder: a systematic review and meta-analysis

The present study aimed to systematically compare overall loss to follow-up, discontinuation rates because of adverse events and discontinuation rates because of a lack of efficacy in published studies assessing the efficacy and tolerability of selective serotonin reuptake inhibitors (SSRIs) compared to other second-generation antidepressants in treating outpatients with major depressive disorder (MDD). We searched MEDLINE, Embase, The Cochrane Library, PsychLit and the International Pharmaceutical Abstracts from 1980 to 2004 (April). Twenty double-blinded, randomized controlled trials met our eligibility criteria and compared SSRIs to other second-generation antidepressants in adult outpatients with MDD. Pooled relative risks of discontinuation rates because of (i) any reason (overall loss to follow-up), (ii) adverse events and (iii) a lack of efficacy did not differ substantially between SSRIs as a class and other second-generation antidepressants. Taking the similar efficacy of second-generation antidepressant into account, our findings suggest that clinicians can focus on other practically or clinically relevant considerations such as costs, differences in side-effect profiles, onset of action or aspects of health-related quality of life to tailor a treatment to an individual patient's needs.

Are SSRIs really more effective for anxious depression?

BACKGROUND

Selective Serotonin Reuptake Inhibitors (SSRIs) are well-established first-line agents for Anxiety Disorders. Anxiety is also a frequent manifestation of major depression. Many psychiatrists assume that anxious depression is more responsive to SSRIs than to other antidepressants. The purpose of this literature review was to determine if SSRIs or any other antidepressants are superior.

METHODS

A computerized search was conducted of double-blind, English-language studies comparing antidepressants available in the United States. Databases searched included Medline and PsycINFO.

RESULTS

SSRIs were not found to be superior to other antidepressants in the treatment of anxious depression.

CONCLUSIONS

The above assumption is not supported. Treatment implications are discussed.

An open treatment trial of venlafaxine for elderly patients with dysthymic disorder

Treatment response and side effects of venlafaxine were evaluated in an open-label trial of elderly outpatients with dysthymic disorder (DD). Patients received flexible dose (up to 300 mg/d) venlafaxine (Effexor XR) for 12 weeks. Of 23 study patients, 18 completed the trial. Fourteen (60.9%) were responders in intent-to-treat analyses with the last observation carried forward, and 77.8% were responders in completer analyses. Nearly half the sample (47.8%) met criteria for remission. In the intent-to-treat sample, increased severity of depression at baseline was associated with superior response, and the presence of cardiovascular disease was associated with poorer response. Venlafaxine open-label treatment was associated with fairly high response rates and generally good tolerability in elderly patients with DD. These results indicate that in elderly patients with DD, placebo-controlled trials of a dual reuptake inhibitor such as venlafaxine would be needed to assess its efficacy or to compare its efficacy to that of other antidepressants.

A review of antidepressant-induced hypomania in major depression: suggestions for DSM-V

OBJECTIVES

To determine if the classification of 'antidepressant-induced hypomania' in DSM-IV is supported by available data.

METHODS

We reviewed the available scientific literature to examine the incidence of mania and hypomania in non-bipolar patients who were treated with antidepressants.

RESULTS

Eighty-nine per cent of studies of antidepressants in major depressive disorder patients reported no cases of treatment-induced hypomania. No instances of treatment-induced hypomania were reported in three large studies of patients with chronic forms of depression.

CONCLUSIONS

The rate of antidepressant-induced hypomania in major depressive disorder is within the rate of misdiagnosis of bipolar depression as unipolar. Depressed patients who experience antidepressant-associated hypomania are truly bipolar.

The treatment of depression with different formulations of venlafaxine: a comparative analysis

Venlafaxine is the first of a group of antidepressants that show dual reuptake inhibition of serotonin and noradrenaline (SNRIs). Originally marketed in an immediate release (IR) formulation a microencapsulated, extended release (XR) formulation is now available. Significant differences exist between these two formulations with respect to pharmacokinetic parameters which have an impact on clinical use. The XR has lower maximum plasma concentrations (Cmax) and achieves these at a later time (higher Tmax). The longer apparent elimination half-life of the drug after single XR doses suggests that it is suitable for once daily dosing compared with the twice daily dosing regimen required by the IR formulation. With respect to antidepressant efficacy the XR formulation is equivalent to other marketed antidepressants and to the IR formulation. Consistent with its pharmacokinetic properties the use of the XR formulation is associated with less nausea and dizziness at the initiation of therapy. While in clinical usage XR might be expected to increase compliance with medication and to reduce discontinuation syndromes there are few comparative studies for which this has been evaluated. The XR formulation of venlafaxine is no worse than the IR form with respect to tolerability and offers some benefits to patients in terms of ease of use. On the other hand there does not appear to be any increase in the efficacy of the active agent.

Diagnosis and treatment of dysthymia in children and adolescents

Dysthymic disorder is a chronic depressive condition occurring in 0.6-4.6% of children and 1.6-8.0% of adolescents. Although symptoms are less severe than those observed in major depression, childhood-onset dysthymic disorder is characterised by a persistent and long-term depressed or irritable mood (mean episode duration 3-4 years), a worse outcome than major depression and, frequently, comorbid disorders (in around 50% of patients). Long-lasting depressive symptoms seem responsible for long-term disabling consequences on social skill learning, psychosocial functioning and consequent professional life, probably contributing to a higher risk of relapse or development of major depression. Consistently, the first episode of major depression occurs 2-3 years after the onset of dysthymic disorder, suggesting that the latter is one of the gateways to recurrent mood disorders. The primary aims of treatment for dysthymic disorder should be to resolve depressive symptoms, reduce the risk of developing other mood disorders over time and strengthen psychosocial functioning, especially in children and adolescents, in order to prevent the potentially serious sequelae of this disorder. As children with dysthymia often have multiple problems, interventions should involve multiple levels and measures: individual psychotherapy, family therapy/education and pharmacological treatment. Psychotherapeutic techniques, such as cognitive-behaviour therapy and interpersonal therapy, have been found to be efficacious interventions in treating children and adolescents with mild to moderate depression in studies including patients with either dysthmia or double depression. SSRIs are the first-line drug treatment for children and adolescents because of their safety, adverse effect profile and ease of use (the safety of paroxetine is currently under investigation). Several nonblind studies have shown the efficacy and good tolerability of SSRIs in children and adolescents with dysthymic disorder, but further research is needed to confirm their efficacy and that of newer antidepressants in the treatment of this disorder. Regardless of whether psychotherapeutic or medical treatments are planned, according to clinical experience, psychoeducational interventions and psychosocial support should be provided to parents and other caregivers during the acute treatment phase to help manage the child's irritable mood and foster a therapeutic alliance and better compliance with treatment. Unfortunately, no studies have focused on continuation treatment of paediatric dysthymic disorder. Given the chronicity, recurrence, psychosocial consequences and peculiar response pattern to treatment of dysthymic disorder, establishing effective 'acute' and 'continuation' interventions in this group of patients should be a priority in mental health management.

Achieving remission from depression with venlafaxine and venlafaxine extended release: a literature review of comparative studies with selective serotonin reuptake inhibitors

OBJECTIVE

To evaluate data supporting the ability of venlafaxine, an antidepressant with a dual mechanism of action, to produce remission from depression.

METHOD

Review of multicentre, double-blind, randomized studies comparing venlafaxine or venlafaxine extended release (XR) with a selective serotonin reuptake inhibitor (SSRI), using Hamilton Depression Rating Scale total scores in the range of < or = 7 and < 10 as the final outcome measure, to evaluate the ability of venlafaxine/venlafaxine XR to produce full remission from depression.

RESULTS

Venlafaxine/venlafaxine XR demonstrated higher rates of remission than did the SSRIs and placebo.

CONCLUSION

With full remission rather than response as the measure of outcome, venlafaxine/venlafaxine XR demonstrated more robust antidepressant efficacy than the SSRIs and placebo. This finding suggests that venlafaxine/venlafaxine XR are appropriate standard-of-care therapies for the treatment of patients with major depressive disorder.

Comparative efficacy between venlafaxine and SSRIs: a pooled analysis of patients with depression

BACKGROUND

Serotonergic and adrenergic enhancement may be synergistic and more effective than serotonergic enhancement alone in treating depression. The dual serotonin-norepinephrine reuptake inhibitor (SNRI) venlafaxine is a dual reuptake inhibitor that may therefore offer greater efficacy than selective serotonin reuptake inhibitors (SSRIs).

METHODS

Data from eight randomized, double-blind, controlled studies were pooled to compare efficacy in depressed patients receiving venlafaxine/venlafaxine extended release (XR), SSRIs, or placebo for

RESULTS

Statistically significant differences in mean HAM-D(21) score decrease between venlafaxine (14.5) and SSRIs (12.6) and between the active treatments and placebo (11.3) were observed. Venlafaxine significantly decreased the mean MADRS scores more than SSRIs (17.8 vs. 15.9), and both treatments were significantly better than placebo (12.9). The same pattern of significance for CGI-I, HAM-D(21), and MADRS response rates between venlafaxine (71%, 64%, and 67%, respectively), SSRIs (64%, 57%, and 59%, respectively), and placebo (50%, 42%, and 41%, respectively) was observed.

CONCLUSIONS

Venlafaxine was significantly more effective than SSRIs in improving depression, perhaps due to enhancing both serotonin and norepinephrine.

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Key Words Collapse

MESH Headings

• Adult
• Anti-Anxiety Agents/therapeutic use
• Antidepressive Agents, Second-Generation/therapeutic use
• Clinical Trials as Topic
• Cyclohexanols/therapeutic use
• Depressive Disorder/drug therapy
• Double-Blind Method
• Female
• Fluoxetine/therapeutic use
• Fluvoxamine/therapeutic use
• Humans
• Male
• Paroxetine/therapeutic use
• Psychiatric Status Rating Scales
• Randomized Controlled Trials as Topic
• Selective Serotonin Reuptake Inhibitors/therapeutic use
• Time Factors
• Venlafaxine Hydrochloride

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Grants Collapse

Affiliation(s)

Stephen M Stahl The Neuroscience Education Institute, Carlsbad, California 92009, USA
Richard Entsuah
Richard L Rudolph

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Global Benefit-risk Evaluation of Antidepressant Action: Comparison of Pooled Data for Venlafaxine, SSRIs, and Placebo

Do antidepressants have an equivalent risk-benefit ratio? Venlafaxine, a serotonin-norepinephrine reuptake inhibitor, is an effective antidepressant for treating major depression. The results of some clinical studies have suggested that venlafaxine may have more potent efficacy in sustaining remission in patients with major depression. Comparative clinical studies, however, lack suitable power to discern treatment differences in safety and also lack a quantitative basis for comparing risk and benefit. A global benefit-risk analysis of pooled data from eight randomized, double-blind, clinical trials of the safety and efficacy of venlafaxine and selective serotonin reuptake inhibitors (SSRIs) was performed. By using the ratio measure of risk-benefit, patients treated with venlafaxine (n=851) for 6-8 weeks experienced a relative gain of 1.57 compared with SSRI-treated patients (n=743) and a relative gain of 2.27 compared with placebo-treated patients (n=439). Subgroup analyses showed a relative gain of 1.35 for venlafaxine-treated patients (n=538) compared with fluoxetine-treated patients (n=549) and a relative gain of 2.53 compared with placebo-treated patients (n=357). A dose-response relationship was apparent between low (<75 mg/day), medium (75-150 mg/day), and high (>150 mg/day) dosages of venlafaxine; r values were 0.758, 0.822, and 1.181, respectively (P=.023, high dosage versus placebo; P=.030, medium dosage versus placebo). Important differences in risk and benefit exist between venlafaxine and SSRIs as a group compared with fluoxetine alone. A significant gain in benefit-risk in the treatment of major depression was observed with an increase in venlafaxine dosage from 75->150 mg/day.

A comparison of paroxetine versus paroxetine plus amisulpride in the treatment of dysthymic disorder: efficacy and psychosocial outcomes

Dysthymic disorder is a chronic depressive condition with considerable psychosocial impairment. Even if DD patients respond to various antidepressant medications, there has been little systematic study on antidepressant-refractory DD. Only a few trials have evaluated the effects of treatment on psychosocial functioning of dysthymic patients. In this 3-month, open-label study, 60 outpatients with DSM-IV criteria for dysthymic disorder who failed to respond to 3-month treatment with paroxetine 20 mg/day were randomly assigned to treatment with paroxetine 40 mg/day or paroxetine 20 mg/day plus amisulpride 50 mg/day. The effects of the two treatments were assessed for both mood symptoms (21-item Hamilton Rating Scale for Depression, Montgomery-Asberg Depression Rating Scale, Clinical Global Impression, severity and improvement) and psychosocial outcomes (DSM-IV Global Assessment of Functioning, Social Adaptation Self-evaluation Scale). Analysis of variance on all rating scales showed that both treatments were effective over this observation period. Response and remission rates did not differ in the treatment groups. A significantly greater psychosocial improvement was observed in the group receiving combined treatment compared with patients receiving paroxetine alone. Both treatments appeared to be effective in our sample of dysthymic subjects. Combined treatment with paroxetine and amisulpride resulted in a better outcome in terms of social functioning.

Efficacy of venlafaxine in patients with major depressive disorder who have unsustained or no response to selective serotonin reuptake inhibitors: an open-label, uncontrolled study

BACKGROUND

Approximately half of patients who are prescribed selective serotonin re-uptake inhibitors (SSRIs) either do not respond to treatment or do not experience a sustained response.

OBJECTIVE

The purpose of this study was to assess the efficacy of venlafaxine immediate-release (IR) and extended-release (XR) in outpatients who either did not respond to SSRI treatment or did not maintain a sustained response.

METHODS

Outpatients who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for major depressive disorder who were previously treated with an SSRI (fluoxetine > or = 20 mg/d; sertraline > or = 50 mg/d; paroxetine > or = 20 mg/d) for > or = 6 weeks, but demonstrated an inadequate or unsustained response, were switched to venlafaxine (IR or XR formulation, 50-400 mg/d, titrated from 37.5 mg/d) for > or = 6 weeks. Response at 6 to 8 weeks was defined as total score < or = 10 on the modified 25-item Hamilton Depression (HAM-D25) rating scale or total score > or = 5 on the 21-item Patient Global Improvement (PGI-21) scale. Remission was defined as a HAM-D25 total score < or = 8 or PGI-21 score > or = 7. Tests were administered by an unblinded, board-certified psychiatrist.

RESULTS

A total of 73 patients (54 women, 19 men; mean age, 38.6 years) were enrolled and treated with venlafaxine IR (n = 63) or venlafaxine XR (n = 10); 33 were SSRI nonresponders and 36 had an unsustained response to SSRI treatment. Four patients receiving venlafaxine IR discontinued due to drug-related adverse events (agitation, sedation, or nausea). Data from these patients were excluded from the analysis. After 6 to 8 weeks of treatment, 94.2% (65/69) of patients were considered responders (HAM-D25 or PGI-21 criteria); 91.3% (63/69) of patients responded to treatment as assessed by both measures. Eighty-seven percent (60/69) and 85.5% (59/69) of patients achieved remission based on HAM-D,5 and PGI-21 criteria, respectively. Response/remission rates were comparable among patients treated with SSRIs, regardless of whether patients had failed to respond to treatment with 1 or 2 SSRIs.

CONCLUSION

Venlafaxine IR/venlafaxine XR may be effective in outpatients with major depressive disorder who do not respond or have an unsustained response to SSRIs. However, randomized, controlled trials are needed before any conclusions can be drawn about the efficacy of this agent in this population.

Dysthymic disorder: treatment with citalopram

We studied 15 patients with dysthymic disorder with open-label citalopram. The purpose of this study was to determine the dose range and safety of citalopram necessary for treatment of patients with dysthymic disorder and to attempt to increase doses in order to enhance remission of patients with dysthymic disorder when treated. Citalopram was well tolerated. The mean dose used in this 10-week study was 37.3 mg and the majority of patients responded to treatment. Various criteria for response and remission were employed. These findings are intended to give guidelines for a subsequent treatment study of dysthymic patients with citalopram using a double-blind placebo-controlled strategy.

Pharmacoeconomic studies of antidepressants: focus on venlafaxine

Newer antidepressants are more expensive in terms of acquisition costs than older drugs. However, cost effectiveness simulations and retrospective analyses of administrative databases of newer antidepressants, including venlafaxine, suggest that the higher acquisition costs may be offset or more than offset by savings of other treatment costs. Because simulations and retrospective studies are vulnerable to multiple methodologic uncertainties, large scale randomized "real-world" cost effectiveness experiments are needed. If venlafaxine in actual practice is more effective or has a more rapid onset of action than SSRIs as suggested by efficacy studies and existing meta-analyses, these effects could translate into pharmacoeconomic advantages.

Remission rates during treatment with venlafaxine or selective serotonin reuptake inhibitors

BACKGROUND

It had been suggested that the antidepressant venlafaxine, which inhibits reuptake of both serotonin and (at higher doses) noradrenaline, may result in better outcomes than treatment with selective serotonin reuptake inhibitors (SSRIs).

AIMS

To compare remission rates during treatment with SSRIs or venlafaxine.

METHOD

Data from eight comparable randomised, double-blind studies of major depressive disorder were pooled to compare remission rates (Hamilton Rating Scale for Depression score < or = 7) during treatment with venlafaxine (n = 851), SSRIs (fluoxetine, paroxetine, fluvoxamine; n = 748) or placebo (four studies; n = 446).

RESULTS

Remission rates were: venlafaxine, 45% (382/851); SSRIs, 35% (260/748); placebo, 25% (110/446) (P: < 0.001; odds ratio for remission is 1.50 (1.3-1.9), favouring venlafaxine v. SSRIs). The difference between venlafaxine and the SSRIs was significant at week 2, whereas the difference between SSRIs and placebo reached significance at week 4. Results were not dependent on any one study or the definition of remission.

CONCLUSIONS

Remission rates were significantly higher with venlafaxine than with an SSRI.

Third-generation antidepressants: do they offer advantages over the SSRIs?

Third-generation antidepressants are a group of antidepressant agents of variable action, not confined to serotonin reuptake inhibition. These agents include venlafaxine, reboxetine, nefazodone and mirtazapine. Claims have been made for these agents in terms of improved efficacy, faster speed of onset of effect and greater safety in the treatment of depression compared with previous medications, such as the selective serotonin reuptake inhibitors (SSRIs). This article reviews the evidence for these improvements. Thirty active comparator studies were reviewed involving the third-generation antidepressant agents. While there were isolated reports of improvements over comparator agents for venlafaxine, reboxetine and mirtazepine, there were no convincing differences between third-generation agents and comparators in terms of overall efficacy, relapse prevention and speed of onset. The third-generation antidepressants were, however, of equivalent safety to SSRIs and maintained improvements in safety over first-generation agents.