Which is more efficacious as an anxiolytic, Buspirone or Bupropion?

Comparison of Buspirone and Bupropion as Anxiolytics

Buspirone is more efficacious as an anxiolytic than bupropion, as bupropion is not indicated or effective for anxiety disorders and may potentially worsen anxiety symptoms in some patients.

Mechanism and Indications

Buspirone

• Specifically developed and FDA-approved as an anxiolytic medication
• Acts as a serotonin 5-HT1A receptor partial agonist
• Indicated for the treatment of generalized anxiety disorder
• Has demonstrated efficacy comparable to benzodiazepines in clinical trials 1, 2
• Does not cause physical dependence or withdrawal symptoms unlike benzodiazepines

Bupropion

• Primarily an antidepressant, not an anxiolytic
• Acts as a norepinephrine-dopamine reuptake inhibitor (NDRI)
• FDA-approved for depression, seasonal affective disorder, and smoking cessation
• Has activating properties that may potentially worsen anxiety in some patients
• Described in guidelines as "anxiolytic" only in the context of smoking cessation, not for anxiety disorders 3

Clinical Evidence Comparison

Buspirone Efficacy for Anxiety

• Demonstrated to be as effective as diazepam in relieving anxiety in outpatient samples 1
• Shown to have similar effectiveness to alprazolam and lorazepam with superior safety profile 4
• Effective in doses of 15-30mg/day for generalized anxiety disorder 5
• Used as an augmentation strategy for anxiety in patients with depression 3

Bupropion and Anxiety

• Not indicated for anxiety disorders in any major clinical guidelines
• May cause activation syndrome which can worsen anxiety symptoms 6
• In the STAR*D trial, when used as an augmentation strategy, bupropion SR had lower discontinuation rates due to adverse events compared to buspirone (12.5% vs. 20.6%; P < 0.001) 3
• However, this was in the context of depression treatment, not primary anxiety treatment

Side Effect Profiles

Buspirone

• Lower sedation profile compared to benzodiazepines 4
• Main side effects include nausea, dizziness, and headache
• No significant impairment of psychomotor or cognitive function 5
• No additive effects with alcohol
• No potential for abuse or dependence

Bupropion

• Activating properties that may exacerbate anxiety
• Common side effects include insomnia, dry mouth, and agitation
• Carries a risk of seizures at higher doses
• No sedative effects, which may be beneficial for depression but problematic for anxiety

Clinical Application

When to Consider Buspirone

• First-line for generalized anxiety disorder when SSRIs are not appropriate
• Augmentation strategy for patients with partial response to SSRIs for anxiety
• Patients with history of substance abuse (due to lack of abuse potential)
• Patients who need to avoid sedation

When to Consider Bupropion

• Not recommended as a primary treatment for anxiety disorders
• May be appropriate for depression, especially with fatigue or low energy
• Smoking cessation (where it has been described as having anxiolytic properties in that specific context) 3
• As an augmentation strategy for breakthrough depression symptoms 6

Important Caveats

• Buspirone may have a delayed onset of action (1-2 weeks) compared to benzodiazepines 5
• Patients previously treated with benzodiazepines may perceive buspirone as less effective 7
• Bupropion should be avoided in patients with a seizure disorder or eating disorders
• Neither medication provides immediate relief of acute anxiety symptoms

Conclusion

Based on the available evidence, buspirone is clearly the superior choice as an anxiolytic compared to bupropion. Bupropion is not indicated for anxiety disorders and may potentially worsen anxiety symptoms due to its activating properties. When specifically treating anxiety, buspirone has demonstrated efficacy in clinical trials and is FDA-approved for this indication, while bupropion has not.