Immediate-release and extended-release formulations of second-generation antidepressants for the treatment of major depressive disorder in adults

IntroductionExtended-release formulations of antidepressants have been marketed as a strategy to increase patient adherence. Changes in the formulation of drugs, however, could be related to changes in efficacy and tolerability. Among second-generation antidepressants, bupropion, fluoxetine, mirtazapine, paroxetine, and venlafaxine are available in immediate- and extended-release formulations.ObjectivesTo compare the efficacy, tolerability, and adherence of immediate- versus extended-release formulations of second-generation antidepressants for the treatment of major depressive disorder (MDD) in adults.AimTo provide an evidence base for clinicians when choosing immediate- or extended-release formulations of antidepressants for the treatment of MDD.MethodsWe conducted a comparative effectiveness review for the U.S. Agency for Healthcare Research and Quality searching PubMed, EMBASE, The Cochrane Library, and the International Pharmaceutical Abstracts up to May 2010. Two people independently reviewed the literature, abstracted data, and rated the risk of bias.ResultsSix RCTs and one observational study provided evidence about the comparative efficacy, tolerability, and adherence of bupropion SR (sustained release) versus bupropion XL (extended release), fluoxetine daily vs. fluoxetine weekly, paroxetine IR (immediate release) versus paroxetine CR (continuous release), and venlafaxine IR versus venlafaxine XR (extended release). Overall, no substantial differences in efficacy and safety could be detected. Open-label and observational evidence indicated better adherence for bupropion XL and fluoxetine weekly than for immediate-release medications. No differences in adherence could be detected between paroxetine IR and paroxetine CR.ConclusionsOur findings indicate similar efficacy and tolerability between immediate- and extended-release formulations. Whether extended-release formulations lead to better adherence remains unclear.</jats:sec

The comparative efficacy of second-generation antidepressants for the accompanying symptoms of depression: a systematic review

IntroductionClinicians treating patients with Major Depressive Disorder (MDD) might favor one second-generation antidepressant (SGA) because of perceived benefits for the accompanying symptoms of MDD.ObjectivesTo compare the efficacy of bupropion, citalopram, desvenlafaxine, duloxetine, escitalopram, fluoxetine, fluvoxamine, mirtazapine, nefazodone, paroxetine, sertraline, trazodone, and venlafaxine for the treatment of the accompanying symptoms of MDD.MethodsThis review is part of a larger review on the comparative effectiveness of SGAs for MDD. We searched MEDLINE, Embase, The Cochrane Library, and the International Pharmaceutical Abstracts up to May 2010. Two persons independently reviewed the literature, abstracted data, and rated the risk of bias.ResultsWe located 26 head-to-head and 7 placebo-controlled trials that provided evidence for this review. We did not locate any studies on treating accompanying appetite change, low energy, melancholia, or psychomotor change. There was no evidence for many comparisons and we were unable to conduct quantitative analysis for any comparisons. For the comparisons that were studied, we concluded that the SGAs are similarly efficacious for treating anxiety, insomnia, pain, and somatization. The strength of the evidence for these conclusions is low (meaning further research is very likely to have an important impact on our confidence in the estimate of the effect and is likely to change the estimate).ConclusionsOur findings indicate that the existing evidence does not warrant the choice of one second-generation antidepressant over another based on greater efficacy for the accompanying symptoms of depression.</jats:sec