Buspirone Side Effects
Buspirone's most common side effects include dizziness (12%), nausea (8%), headache (6%), nervousness (5%), and lightheadedness (3%), with approximately 10% of patients discontinuing treatment due to adverse events, primarily CNS disturbances. 1
Most Common Side Effects
The FDA-approved labeling identifies the following adverse events occurring at ≥1% frequency in controlled trials 1:
Central Nervous System Effects
- Dizziness (12%) - most frequently reported CNS effect 1
- Drowsiness (10%) 1
- Nervousness (5%) 1
- Lightheadedness (3%) 1
- Insomnia (3%) 1
- Decreased concentration (2%) 1
- Excitement (2%) 1
A 2024 meta-analysis confirmed significantly higher rates of dizziness (OR = 4.66,95% CI: 2.07-10.47) compared to placebo 2.
Gastrointestinal Effects
- Nausea (8%) - most common GI complaint 1
- Dry mouth (3%) 1
- Abdominal/gastric distress (2%) 1, 2
- Constipation - significantly elevated (OR = 4.11,95% CI: 1.34-12.55) 2
- Diarrhea (2%) 1
Cardiovascular Effects
- Tachycardia/palpitations (1%) 1
Other Common Effects
Discontinuation Rates
Approximately 10% of patients discontinued buspirone in premarketing trials due to adverse events 1:
- CNS disturbances (3.4%) - primarily dizziness, insomnia, nervousness, drowsiness, lightheadedness 1
- GI disturbances (1.2%) - primarily nausea 1
- Miscellaneous (1.1%) - primarily headache and fatigue 1
Rare but Serious Adverse Events
Neuropsychiatric Effects
- Hallucinations, depersonalization, dysphoria (infrequent) 1
- Suicidal ideation, seizures (infrequent) 1
- Worsening psychosis - rare case reports document exacerbation of psychotic symptoms, particularly in patients with schizoaffective disorder 4
- Akathisia, involuntary movements (infrequent) 1
Cardiovascular Events
- Syncope, hypotension, hypertension (infrequent) 1
- Cerebrovascular accident, congestive heart failure, myocardial infarction (rare) 1
Laboratory Abnormalities
- Elevated hepatic aminotransferases (SGOT, SGPT) - infrequent 1
- Eosinophilia, leukopenia, thrombocytopenia (rare) 1
Important Safety Considerations
Lack of Benzodiazepine-Like Effects
- No significant sedation in most patients 3, 5
- No psychomotor impairment when combined with alcohol or given alone 3
- No abuse, dependence, or withdrawal symptoms reported 3, 5
- Lacks anticonvulsant and muscle-relaxant properties 3
Route of Administration Concerns
Intranasal administration significantly increases bioavailability and adverse effects - oral bioavailability is only ~4% due to first-pass metabolism, but intranasal use bypasses this, leading to enhanced effects and potential for worsening psychiatric symptoms 4.
Dosing-Related Tolerability
A meta-analysis comparing 15 mg BID versus 10 mg TID regimens found similar adverse event profiles, except for significantly higher palpitations with BID dosing (5% vs 1%) 6. The most frequent adverse events in both regimens were dizziness, headache, and nausea 6.
Cognitive Effects (Potential Benefit)
Contrary to typical anxiolytic side effects, buspirone demonstrates cognitive benefits rather than impairment 2:
- Visual learning and memory improvement (g = 0.49,95% CI: 0.21-0.78) 2
- Logical reasoning enhancement (g = 0.42,95% CI: 0.14-0.71) 2
- Attention improvement (g = 0.37,95% CI: 0.13-0.61) 2
Clinical Pitfalls
Delayed onset of therapeutic effect (2-4 weeks) means early side effects may occur before benefits, potentially leading to premature discontinuation 7, 8. Patients must be counseled that anxiety relief is gradual, not immediate 8.
Sporadic use provides no therapeutic benefit - buspirone requires consistent daily administration at stable doses for 2-4 weeks before clinical response can be evaluated 8.