What are the side effects of buspirone (anxiolytic medication)?

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 (≥1% incidence)

The FDA-approved labeling identifies the following side effects occurring at higher rates than placebo in controlled trials 1:

Central Nervous System Effects

• Dizziness (12%) - most frequent side 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 Effects

• Nausea (8%) - second most common side effect 1
• Dry mouth (3%) 1
• Abdominal/gastric distress (2%) 1
• Diarrhea (2%) 1
• Constipation (1%) 1
• Vomiting (1%) 1

Other Common Effects

• Headache (6%) 1
• Fatigue (4%) 1
• Weakness (2%) 1
• Tachycardia/palpitations (1%) 1
• Blurred vision (2%) 1

Discontinuation Rates

Approximately 10% of patients discontinued buspirone in premarketing trials due to adverse events 1. The primary 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 Clinically Important Side Effects

Cardiovascular (Infrequent to Rare)

• Syncope, hypotension, hypertension (infrequent) 1
• Cerebrovascular accident, congestive heart failure, myocardial infarction, cardiomyopathy, bradycardia (rare) 1

Neurological/Psychiatric (Infrequent to Rare)

• Dream disturbances (frequent) 1
• Depersonalization, dysphoria, euphoria, akathisia, hallucinations, involuntary movements (infrequent) 1
• Suicidal ideation and seizures (infrequent) 1
• Stupor, slurred speech, psychosis (rare) 1

Other Systems

• Sexual dysfunction: decreased or increased libido (infrequent), delayed ejaculation and impotence (rare) 1
• Hepatic: increases in aminotransferases (SGOT, SGPT) (infrequent) 1
• Hematologic: eosinophilia, leukopenia, thrombocytopenia (rare) 1

Postmarketing Reports

Additional adverse events reported since market introduction include 1:

• Allergic reactions (including urticaria) and angioedema
• Extrapyramidal symptoms: cogwheel rigidity, dystonic reactions, dyskinesias (acute and tardive), parkinsonism, akathisia, restless leg syndrome
• Serotonin syndrome
• Ataxias, vertigo
• Transient difficulty with recall
• Urinary retention
• Visual changes (including tunnel vision)

Important Clinical Considerations

Comparison to Benzodiazepines

Unlike benzodiazepines, buspirone 2, 3, 4:

• Lacks anticonvulsant and muscle-relaxant properties
• Causes minimal sedation
• Does not impair psychomotor function when combined with alcohol
• Has no reported abuse, dependence, or withdrawal symptoms
• Does not potentiate sedative-hypnotic drugs

Onset and Tolerability

• Buspirone may take 2-4 weeks to become effective for anxiety management 5
• The frequency of adverse effects is generally low 2
• Most side effects are mild and transient 2, 4

Common Pitfalls

• Previous benzodiazepine exposure: Patients with chronic benzodiazepine use may experience reduced efficacy and higher dropout rates with buspirone, particularly if unable to complete adequate washout periods 6
• Nausea and giddiness are the primary side effects leading to early discontinuation 6
• Starting doses should be low (5 mg twice daily) and titrated gradually to minimize side effects 5