06. 11. 2012
SSRIs and the SNRI venlafaxine are currently considered as first-line agents in panic disorder by most guidelines. Tricyclic antidepressants and monoamine oxidase inhibitors are considered as alternative choices only when patients do not seem to respond to or tolerate first-line treatments.
Do newer antidepressants differ in efficacy? This meta analysis by Adrisano et al answer this question.
Articles reporting use of antidepressants in adult panic disorder for at least 6 weeks published up to 2012 Jan were searched. Primary outcome measure was the mean change in panic symptoms from the baseline to the endpoint in patients treated with antidepressants as compared with those treated with placebo.Effect sizes of improvement were calculated by Hedges’s g.
From the originally identified 5169 studies, 50 studies were included in the analysis. 26 studies used a rando mized-controlled design, three studies used a nonrandomized-controlled design, and 21 studies used an uncontrolled design.
FINDINGS:
Panic Symptoms: All antidepressants with the exception of mirtazapine, reboxetine, and fluvoxamine, were significantly more efficacious than placebo on panic symptoms with the following increasing order of effectiveness: citalopram, sertraline, paroxetine, fluoxetine, and venlafaxine. Venlafaxine is most effective in reducing panic symptoms.
Over all anxiety reduction: reboxetine, and sertraline is not significantly different from placebo. paroxetine, fluoxetine, fluvoxamine, citalopram, venlafaxine and mirtazapine had an increasing effect (In order) on the reduction of anxiety symptoms. Mirtazapine most effective in reducing overall anxiety.
Mirtazapine: most effective in reducing general anxiety but not panics. Results should be considered with extreme caution as no placebo-controlled trials of mirtazapine for the treatment of PD have been published thus far.
Dropout rates: Were significantly higher in patients treated with placebo as compared with patients treated with antidepressants, with the only exception of fluvoxamine and reboxetine. In order of decreasing dropout rate: venlafaxine, fluoxetine, sertraline, paroxetine, citalopram, and mirtazapine.
Authors provide sensitivity analysis data based on method of study, sponsorship, and presence of comorbidity.
Limitations: both controlled nad uncontrolled studies were included.for studies that did not include a placebo control group, authors calculated a virtual placebo. A uniform measure to calculate the clinical improvement in panic and anxiety levels from the baseline to the endpoint was not used. Missing SDs were calculated by the weighted mean of SDs provided by studies investigating the same measure and was applied to studies not providing this measure.Bupropion, duloxetine, escitalopram, and milnacipran were excluded from the analyses because they were investigated in less than three studies.
Conclusions: Reboxetine is ineffective in both panic and anxiety symptoms in Panic disorder. Mirtazapine and flouxamine are not useful in reducing panic symptoms. Citalopram, sertraline, paroxetie, flouxetine and venlafaxine are effective in reducing panic symptoms.
Psychiatrist:Update 
Results of study not so clear without comparission with escitaloprem
Further evidences in future needed.
Duloxetine is an SNRI, but there is no mention of this drug in the study. It is a safer drug because there is less chance of hypertension in treated patients, as well as titration of dose is not required.
What about anxiety like symptoms experienced sometimes with fluoxetine? as it is given in some texts.
SSRIs do have that side effect, early during the course.However, they are effective in anxiety disorders despite that side effect in the initial period.