Buspirone Side Effects
Buspirone causes dizziness, nausea, and headache as the most common side effects, with approximately 10% of patients discontinuing treatment due to adverse events, primarily CNS disturbances including dizziness, nervousness, and lightheadedness. 1
Most Common Side Effects
The FDA-approved labeling identifies the following most frequently reported adverse events that occur more commonly than placebo 1:
- Dizziness (12%) - most common CNS effect
- Nausea (8%) - most common gastrointestinal effect
- Headache (6%)
- Nervousness (5%)
- Lightheadedness (3%)
- Drowsiness (10%)
- Excitement (2%)
Side Effects Leading to Treatment Discontinuation
Approximately 10% of patients discontinued buspirone in premarketing trials due to adverse events 1. The specific reasons for discontinuation included:
- CNS disturbances (3.4%) - primarily dizziness, insomnia, nervousness, drowsiness, and lightheadedness 1
- Gastrointestinal disturbances (1.2%) - primarily nausea 1
- Miscellaneous complaints (1.1%) - primarily headache and fatigue 1
- Multiple complaints (3.4%) - no single primary complaint 1
Additional Reported Side Effects (≥1% Incidence)
Cardiovascular
- Tachycardia/palpitations (1%) 1
Gastrointestinal
- Dry mouth (3%)
- Abdominal/gastric distress (2%)
- Diarrhea (2%)
- Constipation (1%)
- Vomiting (1%) 1
Neurological
- Decreased concentration (2%)
- Confusion (2%)
- Numbness (2%)
- Paresthesia (1%)
- Incoordination (1%)
- Tremor (1%) 1
Psychiatric
- Insomnia (3%)
- Anger/hostility (2%)
- Depression (2%) 1
Other
- Fatigue (4%)
- Weakness (2%)
- Blurred vision (2%)
- Skin rash (1%)
- Sweating/clamminess (1%)
- Musculoskeletal aches/pains (1%) 1
Key Safety Advantages Compared to Benzodiazepines
Buspirone demonstrates a significantly safer profile than benzodiazepines, with no sedation, cognitive impairment, abuse potential, dependence, or withdrawal symptoms. 2, 3
- Does not impair psychomotor or cognitive function 3
- No additive effects with alcohol 3
- No abuse, dependence, or withdrawal symptoms reported 2
- Lacks anticonvulsant and muscle-relaxant properties 2
- Causes only minimal sedation 2
Critical Clinical Caveats
Delayed Onset of Action
- Buspirone requires 1-2 weeks for onset of anxiolytic effect, making it unsuitable for patients requiring immediate symptom relief 4, 5
- Patient motivation and compliance support is necessary during this lag period 3
Rare but Serious Adverse Event
- Worsening psychosis has been reported in patients with schizoaffective disorder, likely related to buspirone's antagonism at presynaptic dopamine D2, D3, and D4 receptors 6
- Avoid in patients with psychotic disorders 6
Route of Administration Concerns
- Intranasal administration dramatically increases bioavailability (oral bioavailability is only 3.9-4%) and may enhance adverse effects 2, 6
- Monitor for medication diversion or misuse 6