Buspirone Side Effects
Buspirone's most common side effects include dizziness (12%), nausea (8%), headache (6%), nervousness (5%), and lightheadedness, which occur more frequently than with placebo. 1
Most Common Side Effects (≥1% incidence)
According to FDA labeling data from controlled clinical trials, the following side effects occur at rates significantly higher than placebo: 1
Central Nervous System
- Dizziness (12%) - most common CNS effect 1
- Drowsiness (10%) 1
- Nervousness (5%) 1
- Insomnia (3%) 1
- Lightheadedness (3%) 1
- Decreased concentration (2%) 1
- Excitement (2%) 1
- Anger/hostility (2%) 1
- Confusion (2%) 1
- Depression (2%) 1
Gastrointestinal
- Nausea (8%) - second most common overall side effect 1
- Dry mouth (3%) 1
- Abdominal/gastric distress (2%) 1
- Diarrhea (2%) 1
- Constipation (1%) 1
- Vomiting (1%) 1
General
Cardiovascular
- Tachycardia/palpitations (1%) 1
Other Systems
- Blurred vision (2%) 1
- Numbness (2%) 1
- Paresthesia (1%) 1
- Incoordination (1%) 1
- Tremor (1%) 1
- Skin rash (1%) 1
Discontinuation Rates
Approximately 10% of patients discontinued buspirone in premarketing trials due to adverse events. 1 The most common reasons for discontinuation were:
- CNS disturbances (3.4%): primarily dizziness, insomnia, nervousness, drowsiness, and lightheadedness 1
- GI disturbances (1.2%): primarily nausea 1
- Miscellaneous (1.1%): primarily headache and fatigue 1
- Multiple complaints (3.4%) 1
Less Common but Notable Side Effects
Infrequent (1/100 to 1/1,000 patients)
Cardiovascular: Syncope, hypotension, hypertension 1
CNS: Depersonalization, dysphoria, noise intolerance, euphoria, akathisia, fearfulness, hallucinations, involuntary movements, slowed reaction time, suicidal ideation, seizures 1
Gastrointestinal: Flatulence, anorexia, increased appetite, salivation, irritable colon, rectal bleeding 1
Genitourinary: Urinary frequency, urinary hesitancy, menstrual irregularity, dysuria 1
Sexual: Decreased or increased libido 1
Musculoskeletal: Muscle cramps, muscle spasms, rigid/stiff muscles, arthralgias 1
Respiratory: Hyperventilation, shortness of breath, chest congestion 1
EENT: Tinnitus, sore throat, nasal congestion, altered taste, altered smell 1
Skin: Edema, pruritus, flushing, easy bruising, hair loss 1
Laboratory: Increases in hepatic aminotransferases (SGOT, SGPT) 1
Rare (<1/1,000 patients)
Serious cardiovascular events: Cerebrovascular accident, congestive heart failure, myocardial infarction, cardiomyopathy, bradycardia 1
Serious CNS events: Claustrophobia, cold intolerance, stupor, slurred speech, psychosis 1
Sexual dysfunction: Delayed ejaculation, impotence 1
Hematologic: Eosinophilia, leukopenia, thrombocytopenia 1
Important Clinical Distinctions
Buspirone lacks several side effects common to benzodiazepines: 2, 3, 4
- Minimal sedation 2
- No anticonvulsant effects 2
- No muscle relaxant properties 2
- Does not impair psychomotor function 2
- Does not potentiate alcohol effects 4
- No dependence, abuse potential, or withdrawal symptoms 2, 3
Postmarketing Reports
Rare postmarketing reports include: 1
- Allergic reactions (urticaria, angioedema)
- Extrapyramidal symptoms (cogwheel rigidity, dystonia, dyskinesias, parkinsonism)
- Serotonin syndrome
- Ataxia
- Restless leg syndrome
- Urinary retention
- Visual changes including tunnel vision
Key Clinical Considerations
Onset of therapeutic effect: Buspirone requires 2-4 weeks to become effective for anxiety management. 5 This delayed onset means patients may experience side effects before experiencing benefits, which can affect adherence.
Starting dose: Initial dosing typically begins at 5 mg twice daily to minimize side effects, with maximum recommended dosing of 20 mg three times daily. 5
Common pitfall: The most frequent reason for treatment failure is inadequate trial duration—patients may discontinue due to early side effects (especially nausea and dizziness) before the therapeutic window of 2-4 weeks is reached. 5, 1