Side Effects of Buspirone (Buspar)
Buspirone commonly causes dizziness, nausea, headache, nervousness, lightheadedness, and excitement as its primary side effects, with approximately 10% of patients discontinuing treatment due to adverse events in clinical trials. 1
Common Side Effects
Based on FDA-approved drug labeling, the most frequently reported side effects of buspirone include:
Central Nervous System (CNS) Effects
- Dizziness (12% vs 3% placebo)
- Drowsiness (10% vs 9% placebo)
- Nervousness (5% vs 1% placebo)
- Insomnia (3% vs 3% placebo)
- Lightheadedness (3%)
- Decreased concentration (2% vs 2% placebo)
- Excitement (2%)
- Anger/hostility (2%)
- Confusion (2%)
- Depression (2% vs 2% placebo)
Gastrointestinal Effects
- Nausea (8% vs 5% placebo)
- Dry mouth (3% vs 4% placebo)
- Abdominal/gastric distress (2% vs 2% placebo)
- Diarrhea (2%)
- Constipation (1% vs 2% placebo)
- Vomiting (1% vs 2% placebo)
Other Common Effects
- Headache (6% vs 3% placebo)
- Fatigue (4% vs 4% placebo)
- Tachycardia/palpitations (1% vs 1% placebo)
- Blurred vision (2%)
- Weakness (2%)
- Sweating/clamminess (1%)
Less Common Side Effects
The FDA label also reports less frequent adverse events that occurred during premarketing evaluation 1:
Cardiovascular
- Nonspecific chest pain (frequent)
- Syncope, hypotension, hypertension (infrequent)
- Cerebrovascular accident, congestive heart failure, myocardial infarction (rare)
Neurological
- Dream disturbances (frequent)
- Paresthesia, numbness, incoordination, tremor (infrequent)
- Depersonalization, dysphoria, akathisia, involuntary movements (infrequent)
- Slurred speech, psychosis (rare)
Sexual Function
- Decreased or increased libido (infrequent)
- Delayed ejaculation and impotence (rare)
Important Considerations
Discontinuation Patterns
Approximately 10% of patients discontinue buspirone due to adverse events, with the most common reasons being 1:
- CNS disturbances (3.4%) - primarily dizziness, insomnia, nervousness, drowsiness
- Gastrointestinal disturbances (1.2%) - primarily nausea
- Miscellaneous disturbances (1.1%) - primarily headache and fatigue
Pharmacological Profile
Buspirone has a unique pharmacological profile as a partial agonist for serotonin 5-HT1A receptors with some antagonist activity at dopamine D2 receptors 2. Unlike benzodiazepines, buspirone:
- Does not cause significant sedation
- Lacks anticonvulsant and muscle-relaxant properties
- Has no reported abuse potential or withdrawal symptoms
- Does not impair psychomotor performance when combined with alcohol 3
Dosing Considerations
The side effect profile may be affected by dosing regimen. A meta-analysis comparing twice-daily versus three-times-daily dosing found similar adverse event profiles, with the exception of palpitations being more common in the twice-daily regimen (5% vs 1%) 4.
Clinical Pearls
- Side effects are typically mild to moderate and often diminish with continued treatment
- Buspirone has a short half-life (2-3 hours) and requires multiple daily dosing 5
- Unlike benzodiazepines, buspirone does not cause physical dependence or withdrawal symptoms
- Buspirone takes 2-4 weeks to reach full therapeutic effect, which may affect patient adherence if side effects occur early in treatment
- Patients previously treated with benzodiazepines may perceive buspirone as less effective due to the absence of immediate sedative effects 6
When prescribing buspirone, it's important to counsel patients about the common side effects and the delayed onset of therapeutic action to improve treatment adherence and outcomes.