What is the recommended dosing for Buspar (buspirone)?

Buspirone (Buspar) Dosing Recommendations

The recommended dosing for buspirone (Buspar) is 15-30 mg per day divided into 2-3 doses, with initial dosing of 5 mg three times daily and gradual titration based on response. 1

Initial Dosing and Titration

• Starting dose: 5 mg three times daily (15 mg/day)
• Titration: Increase by 5 mg per day every 2-3 days as needed
• Maintenance dose: 15-30 mg per day, divided into 2-3 doses
• Maximum dose: 60 mg per day (rarely needed)

Administration Options

• Three times daily (TID): 10 mg three times daily (30 mg total)
• Twice daily (BID): 15 mg twice daily (30 mg total)
  • Both regimens show similar efficacy and safety profiles 2
  • BID dosing may offer better convenience and potentially higher compliance

Special Populations

Elderly Patients

• Start with lower doses: 5 mg twice daily (10 mg/day)
• Titrate more slowly: increase by 5 mg every 3-4 days
• Effective mean dose in elderly: 18 mg/day 3
• Well-tolerated in elderly patients with concomitant medical conditions

Hepatic Impairment

• Use with caution - plasma concentrations can be 15-fold higher 4
• Start with 2.5 mg once or twice daily
• Titrate very slowly based on response and tolerability

Renal Impairment

• Reduce initial dose by 25-50%
• Plasma concentrations can be 2-fold higher in renal impairment 4

Drug Interactions

Dose Adjustment Required

• CYP3A4 inhibitors (require significant dose reduction):
  • Erythromycin: Reduce to 2.5 mg twice daily 1
  • Itraconazole: Reduce to 2.5 mg once daily 1
  • Nefazodone: Reduce to 2.5 mg once daily 1
  • Diltiazem/Verapamil: Reduce to 2.5 mg twice daily 1
  • Grapefruit juice: Avoid large amounts 1

Other Significant Interactions

• CYP3A4 inducers (may require dose increase):
  • Rifampin: May need dose adjustment to maintain effect 1
  • Phenytoin, phenobarbital, carbamazepine: May need higher buspirone doses 1

Duration of Treatment

• Evaluate efficacy after 4-6 weeks of treatment at therapeutic doses
• For chronic anxiety, reevaluate need for continued therapy periodically 5
• Long-term therapy (up to one year) has been shown to be safe with no emergence of new side effects 5
• No withdrawal syndrome observed when discontinued after 6+ months of therapy 5

Common Pitfalls and Caveats

1. Delayed onset of action: Buspirone typically takes 2-4 weeks for full therapeutic effect, unlike benzodiazepines which work immediately
2. Abrupt switching: When transitioning from benzodiazepines to buspirone, gradual tapering of the benzodiazepine is necessary to avoid withdrawal symptoms
3. Underdosing: Many treatment failures occur due to inadequate dosing or insufficient duration of treatment
4. Drug interactions: Failure to adjust dosing when adding CYP3A4 inhibitors can lead to significant side effects
5. Discontinuation: No tapering is required when stopping buspirone, as it does not cause withdrawal symptoms

Buspirone has been shown to be effective at doses up to 90 mg/day in clinical trials for depression with anxiety 6, but standard dosing of 15-30 mg/day is sufficient for most patients with anxiety disorders.