What are the side effects of Buspar (buspirone)?

Buspirone Side Effects

Buspirone is generally well-tolerated with the most common side effects being dizziness, nausea, headache, nervousness, and lightheadedness, occurring in approximately 3-12% of patients. 1

Most Common Side Effects

The FDA-approved drug label identifies the following most frequently reported adverse events in controlled clinical trials 1:

• Dizziness (12%) - the most common side effect 1
• Drowsiness (10%) 1
• Nausea (8%) 1
• Headache (6%) 1
• Nervousness (5%) 1
• Lightheadedness (3%) 1
• Excitement (2%) 1

Gastrointestinal Effects

Buspirone commonly causes GI disturbances 1:

• Dry mouth (3-4%) 1
• Abdominal/gastric distress (2%) 1
• Diarrhea (2%) 1
• Constipation (1-2%) 1

Cardiovascular Effects

• Tachycardia/palpitations (1%) 1
• Nonspecific chest pain occurs frequently (≥1/100 patients) 1

Central Nervous System Effects

Beyond the common effects listed above, additional CNS effects include 1:

• Insomnia (3%) 1
• Decreased concentration (2%) 1
• Confusion (2%) 1
• Depression (2%) 1
• Dream disturbances (frequent) 1

Discontinuation Rates

Approximately 10% of patients discontinued buspirone during premarketing trials due to adverse events 1. The primary reasons for discontinuation were 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

While uncommon, clinicians should be aware of potentially serious effects 1:

• Movement disorders - rare cases of persistent dystonia, tremors, and exacerbation of tardive dyskinesia have been reported 2
• Seizures (rare, <1/1,000 patients) 1
• Suicidal ideation (infrequent, 1/100 to 1/1,000 patients) 1
• Hallucinations (infrequent) 1

Important Clinical Considerations

Buspirone lacks the sedative, muscle relaxant, and anticonvulsant properties of benzodiazepines 3. This translates to 4, 3:

• Minimal sedation compared to benzodiazepines 4
• No psychomotor impairment when combined with alcohol or given alone 4
• No abuse potential, dependence, or withdrawal symptoms reported 4, 3

Onset and Tolerability

Buspirone requires 2-4 weeks to become effective for anxiety management 5. The frequency of adverse effects is generally low, and most side effects are mild 4. Meta-analysis data confirms that buspirone maintains an excellent safety and tolerability profile across different dosing regimens 6.

Laboratory Abnormalities

Infrequent laboratory changes include 1:

• Increases in hepatic aminotransferases (SGOT, SGPT) 1
• Rare: eosinophilia, leukopenia, thrombocytopenia 1