Yes, there are studies evaluating the effectiveness of augmenting SSRIs or SNRIs with either mirtazapine (Remeron) or bupropion (Wellbutrin) in treatment-resistant depression (TRD). Here’s a summary of the findings:
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Mirtazapine (Remeron) Augmentation
A notable randomized controlled trial (RCT) published in the BMJ assessed the addition of mirtazapine to existing SSRI or SNRI therapy in patients with TRD. The study concluded that mirtazapine augmentation did not provide a clinically significant benefit over placebo. Furthermore, patients receiving mirtazapine were more likely to experience adverse effects and discontinue treatment compared to those on placebo.
While some smaller studies and case reports have suggested potential benefits of combining mirtazapine with SSRIs or SNRIs, the overall evidence does not robustly support its efficacy as an augmentation strategy in TRD.
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Bupropion (Wellbutrin) Augmentation
In contrast, bupropion has been studied as an augmentation agent in TRD. The STAR*D trial, a large-scale study, included a level where patients who did not respond to citalopram (an SSRI) were randomized to receive augmentation with either bupropion or buspirone. The results showed similar remission rates between the two groups, but bupropion was better tolerated and associated with fewer side effects.
Additionally, bupropion’s unique pharmacological profile—norepinephrine-dopamine reuptake inhibition—may help alleviate specific symptoms like fatigue and sexual dysfunction, which are sometimes exacerbated by SSRIs or SNRIs.
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Comparative Insights
Direct head-to-head comparisons between mirtazapine and bupropion as augmentation strategies are limited. However, the available evidence suggests that bupropion may offer advantages in terms of tolerability and symptom relief, particularly for patients experiencing fatigue or sexual side effects from SSRIs or SNRIs.
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Conclusion:
While both mirtazapine and bupropion have been explored as augmentation options in TRD, current evidence favors bupropion due to its tolerability and potential to address specific residual symptoms. Nonetheless, individual responses can vary, and treatment should be tailored to each patient’s clinical profile and history.
