Can Buspirone Cause Fatigue?
Yes, buspirone can cause fatigue, though it occurs less frequently than with benzodiazepines and is generally reported as mild to moderate in severity.
Evidence from FDA Drug Labeling
The FDA-approved prescribing information for buspirone lists fatigue as a common adverse effect occurring in 4% of patients in placebo-controlled trials, compared to 4% in the placebo group 1. While the incidence was similar to placebo in controlled trials, fatigue was identified as one of the adverse events that led to treatment discontinuation in approximately 1.1% of patients during premarketing studies 1.
Importantly, buspirone causes significantly less fatigue compared to benzodiazepines 1. In comparative trials, fatigue occurred less frequently in buspirone-treated patients than in those receiving diazepam, clorazepate, lorazepam, or alprazolam 2.
Additional Adverse Effects to Monitor
Beyond fatigue, the FDA labeling identifies the most common adverse effects as 1:
- Dizziness (12%) - most frequent adverse effect
- Drowsiness (10%) - similar to placebo rates
- Nausea (8%)
- Headache (6%)
- Nervousness (5%)
- Lightheadedness (3%)
The FDA specifically notes that buspirone "is less sedating than other anxiolytics and does not produce significant functional impairment," though CNS effects in individual patients may not be predictable 1.
Clinical Context and Paradoxical Effects
A critical caveat: buspirone can paradoxically reduce fatigue in certain contexts. Research demonstrates that buspirone actually decreased time to volitional fatigue during exercise by approximately one-third (from 26 to 16 minutes) in healthy subjects 3. This suggests buspirone may affect central fatigue mechanisms through serotonergic pathways, though the clinical relevance to resting fatigue in anxious patients differs.
More recent meta-analysis data from 2024 shows buspirone demonstrated cognitive benefits including improved attention, visual learning, and logical reasoning 4, which would typically be inconsistent with clinically significant fatigue.
Practical Management Approach
When prescribing buspirone:
- Inform patients that fatigue may occur but is typically mild and occurs at similar rates to placebo
- Start with low doses (5 mg twice daily) and titrate gradually to minimize adverse effects 5
- Monitor specifically for:
- Dizziness and lightheadedness (more common than fatigue)
- Gastrointestinal symptoms (nausea, gastric distress)
- Paradoxical activation/nervousness
- Reassure patients that unlike benzodiazepines, buspirone causes significantly less sedation and fatigue
- Consider timing: The medication may take 2-4 weeks to become fully effective for anxiety 5, so early fatigue complaints should be reassessed after this period
Important Safety Consideration
The FDA labeling emphasizes that while buspirone is less sedating than alternatives, patients should still be cautioned about operating automobiles or complex machinery until they know how the medication affects them individually 1. This precaution applies even though formal studies show buspirone does not significantly impair motor and mental performance.