All of the other meta-analyses focused on studies that directly compared classes of drugs. We used a slightly different approach in that, although we used only RCTs, we combined results within drug classes rather than among classes. The reason for that approach was a lack of comparative studies for the newer class (ie, SNRIs). However, because more drugs in that class are being developed, such as mirtazapine , there may soon be an adequate number of drugs on which to apply alternate meta-analytical techniques.
On the other hand, the data presented here provide point estimates for success as well as dropout rates due to both ADRs and perceived lack of effect for these classes of drugs. These estimates may serve as inputs into economic analyses of antidepressants.
The present meta-analysis does not report rates of ADRs because of concern about RCTs, which seldom are of sufficient duration to identify common problems associated with long term therapy. Large databases that examine patients over time are a preferable source of data for the examination of ADR rates and severities. ventolin inhaler
One limitation of this study is the use of single arms. Because there is no balance from a control group, the possibility of bias exists. However, we used only RCTs for efficacy rates, and most of the comparators were active drugs such as amitriptyline or imipramine. Those results were, therefore, included in the analyses of the other classes of drugs, which decreases the bias somewhat. Although we used data from open trials for dropout rates, the rates from open trials were actually higher than those from RCTs in seven of eight cases. In other words, the RCTs produced more conservative (ie, lower) estimates of dropouts than did open trials.
There is a need for more head-to-head trials between new drugs and standard therapy and for more high quality RCTs in general. The data available are inadequate to answer many critical clinical questions.
The present analysis indicates that patients treated with ven-lafaxine achieved higher success rates and lower discontinuation rates than those receiving either SSRIs or TCAs. Venlafax-ine may be clinically superior to other classes in treating adults with major depressive disorder. Further research in the form of head-to-head RCTs is required to clarify these findings.