From the Guidelines
Buspirone and bupropion can be effective adjuncts to SSRIs, but bupropion is preferred for residual depression, fatigue, or sexual side effects, while buspirone is better for residual anxiety symptoms, as evidenced by a study published in 2016 1. When considering the efficacy of buspirone versus bupropion as an adjunct to SSRIs, it's essential to evaluate the specific residual symptoms needing treatment.
- Buspirone is generally preferred for addressing residual anxiety symptoms with SSRIs, and is typically started at 7.5-15mg twice daily and titrated up to 30-60mg daily in divided doses.
- Bupropion is better for residual depression, fatigue, or sexual side effects, and is usually started at 150mg XL once daily, potentially increasing to 300mg daily after 1-2 weeks. The choice between buspirone and bupropion should be guided by the specific residual symptoms needing treatment, as both medications have different effects on symptoms such as anxiety, depression, and sexual side effects, as reported in a study published in the Annals of Internal Medicine 1. Key considerations when choosing between buspirone and bupropion include:
- The potential for buspirone to take 2-4 weeks for full effect and may cause dizziness or headaches.
- The potential for bupropion to work within 1-2 weeks and may cause insomnia, agitation, or seizures (rare).
- The fact that neither medication typically worsens SSRI sexual side effects, and bupropion often improves them, as noted in a study published in 2016 1.
- The need for monitoring when combining bupropion with fluoxetine or paroxetine due to potential drug interactions affecting bupropion levels, as recommended by the American College of Physicians 1.
From the FDA Drug Label
The efficacy of buspirone hydrochloride tablets has been demonstrated in controlled clinical trials of outpatients whose diagnosis roughly corresponds to Generalized Anxiety Disorder (GAD). Many of the patients enrolled in these studies also had coexisting depressive symptoms and buspirone hydrochloride tablets relieved anxiety in the presence of these coexisting depressive symptoms
The FDA drug label does not answer the question.
From the Research
Efficacy of Buspirone versus Bupropion as an Adjunct to SSRIs
- The efficacy of buspirone (anxiolytic) versus bupropion (antidepressant) as an adjunct to selective serotonin reuptake inhibitors (SSRIs) can be evaluated based on available studies 2, 3, 4, 5, 6.
- Buspirone has been found to be effective in treating generalized anxiety disorders and may be beneficial in augmenting SSRIs in patients with severe depression 4, 5.
- A study found that patients with severe depressive symptoms may benefit from augmentation with buspirone, with a significantly greater reduction in Montgomery-Asberg Depression Rating Scale (MADRS) score in the buspirone group compared to placebo 5.
- Bupropion, on the other hand, was found to be ineffective in treating post-traumatic stress disorder (PTSD) in an open-label study 3.
- In terms of pharmacokinetics, buspirone is rapidly absorbed and extensively metabolized, with a mean elimination half-life of 2.5 hours 2.
- The use of buspirone as an adjunct to SSRIs may be considered in patients who do not respond to SSRIs alone, particularly those with severe depressive symptoms 5.
- In older adults, buspirone may be considered as an alternative to SSRIs, especially if avoiding sexual side effects is a priority 6.
Comparison of Buspirone and Bupropion
- Buspirone and bupropion have different mechanisms of action, with buspirone acting on the 5-HT1A receptors and bupropion acting as a noradrenergic reuptake inhibitor 2, 3.
- Buspirone has been found to be effective in treating anxiety disorders, while bupropion has been found to be ineffective in treating PTSD 3, 4.
- The pharmacokinetics of buspirone and bupropion also differ, with buspirone having a shorter elimination half-life and being more extensively metabolized 2.