RTI International - News Release - 1.24.2007
New Report Finds No Significant Differences in Effectiveness of Antidepressants
RESEARCH TRIANGLE PARK, N.C. -- Researchers found no significant differences in the effectiveness of popular antidepressants, according to a new report by the RTI International-University of North Carolina at Chapel Hill Evidence-based Practice Center.
The report found that second-generation antidepressants, the mostly commonly prescribed depression medications, were similar in efficacy and effectiveness for the treatment of acute-phase depression, but exhibited some differences among their side effects.
"Second-generation antidepressants provide hope for many of the millions of Americans who struggle with depression," said the Agency for Healthcare Research and Quality Director Carolyn M. Clancy, M.D. "But often trying to find the right drug is trial and error, and in many cases relief is temporary or comes with serious side effects. It's clear we need more evidence to help patients and their doctors make the best choices."
The report is based on a systematic review of 293 studies that assessed 12 commonly prescribed second-generation antidepressants: bupropion, citalopram, duloxetine, escitalopram, fluoxetine, fluvoxamine, mirtazapine, nefazodone, paroxetine, sertraline, trazodone, and venlafaxine. The studies included randomized controlled trials with active or placebo controls, observational studies and systematic reviews.
"Based on our review of the available research, we found very little difference in the effectiveness of various antidepressants," said Gerald Gartlehner, M.D., M.P.H., lead author of the report and researcher at the University of North Carolina at Chapel Hill, adding that "nevertheless, the drugs are not identical." "We found slight differences in some of the adverse effects of the various medications, and these may affect individual preferences for certain medications."
According to the report, 61 percent of patients in efficacy trials experienced at least one adverse side effect to antidepressants, including constipation, diarrhea, dizziness, headache, insomnia, and vomiting.
"Because of the high incidence of side effects and the fact that only about 60 percent of patients respond to the initial treatment regimen, many patients try more than one medication before finding an effective treatment," said Linda Lux, M.P.A., RTI researcher. "Overall, the second-generation antidepressants studies have similar adverse events profiles, but predicting which medication will be most effective or best tolerated by any individual patient is not yet possible."
According to the authors, more research needs to be conducted to determine the effects that dosage and duration of antidepressant treatment have on the medication's effectiveness. The researchers also suggest a need to evaluate whether the effectiveness of second-generation antidepressants differs in patients who also suffer from anxiety, insomnia, pain, or fatigue.
The evidence review was conducted by RTI-UNC Evidence-based Practice Center, a collaboration between RTI and the five health professions schools and the Cecil G. Sheps Center for Health Services Research at the University of North Carolina at Chapel Hill. The project was supported by the Agency for Healthcare Research and Quality (AHRQ).