What is the recommended dosing for Buspar (buspirone)?

Buspirone (BuSpar) Dosing Guidelines

The recommended dosing for buspirone (BuSpar) is to start at 5 mg twice daily and titrate up to a maximum of 20 mg three times daily, with most patients responding to 15-30 mg total daily dose. 1

Initial Dosing and Titration

• Starting dose: 5 mg twice daily
• Titration: Increase by 5 mg per day every 2-3 days as needed and tolerated
• Maintenance dose: 15-30 mg per day (divided into 2-3 doses)
• Maximum dose: 60 mg per day (20 mg three times daily) 2

Dosing Schedule Options

• Twice daily (BID) regimen: 15 mg twice daily (total 30 mg/day)
• Three times daily (TID) regimen: 10 mg three times daily (total 30 mg/day)

Both BID and TID regimens show similar efficacy and safety profiles, though BID dosing may offer better convenience and compliance 3.

Special Populations

Elderly Patients

• Start at the lower end of the dosing range (5 mg twice daily)
• Mean effective dose in elderly is approximately 18 mg/day 4
• Elderly patients generally tolerate buspirone well, even with concomitant medications for other conditions

Hepatic Impairment

• Significant dose reduction required
• Plasma concentrations can be 15-fold higher in patients with hepatic impairment 5
• Consider starting at 2.5 mg once or twice daily and titrate cautiously

Renal Impairment

• Dose reduction recommended
• Plasma concentrations can be 2-fold higher in patients with renal impairment 5

Drug Interactions and Dosing Adjustments

Dose Reduction Required With:

• CYP3A4 inhibitors: Use lower doses (e.g., 2.5 mg daily or twice daily) when combined with:
  • Erythromycin (5-fold increase in buspirone levels)
  • Itraconazole (13-fold increase)
  • Nefazodone (up to 20-fold increase)
  • Diltiazem or verapamil (4-5 fold increase)
  • Grapefruit juice (4-9 fold increase) 1

Dose Increase May Be Needed With:

• CYP3A4 inducers: May need higher buspirone doses when combined with:
  • Rifampin (reduces buspirone levels by ~90%)
  • Phenytoin, phenobarbital, carbamazepine 1

Clinical Pearls

• Onset of action: Buspirone typically takes 2-4 weeks to become effective for anxiety 2
• Duration of therapy: While long-term anxiolytic therapy is not generally recommended, buspirone has been safely used for up to one year 6
• Periodic reevaluation: The need for continued therapy should be reassessed periodically
• Food effect: Taking with food increases buspirone bioavailability approximately 2-fold 5
• No withdrawal syndrome: Unlike benzodiazepines, abrupt discontinuation after long-term use does not typically cause withdrawal symptoms 6

Monitoring

• Assess therapeutic response after 2-4 weeks (full effect may take up to 4-8 weeks)
• Monitor for common side effects: dizziness, headache, nausea, and nervousness
• No routine laboratory monitoring is required

Buspirone offers an advantage over benzodiazepines for anxiety management due to its lack of significant sedation, dependence potential, or withdrawal symptoms, making it particularly suitable for patients requiring long-term anxiety management.