What is the recommended initiation protocol for Buspar (buspirone)?

Buspirone Initiation Protocol

Start buspirone at 5 mg twice daily and titrate upward every 5-7 days by increments of 5 mg/day until reaching the target dose of 15-30 mg/day in divided doses, with a maximum of 60 mg/day if needed. 1

Initial Dosing

• Begin with 5 mg twice daily (10 mg total daily dose) 1
• Alternative starting dose of 7.5 mg twice daily (15 mg/day) is also appropriate for most patients 2, 3
• The initial low dose minimizes early adverse effects while allowing assessment of tolerability 1

Titration Schedule

• Increase dose every 5-7 days using increments equal to the initial starting dose 1
• Typical titration: 5 mg BID → 7.5 mg BID → 10 mg BID → 15 mg BID 1
• Continue titration until therapeutic benefits become apparent or significant side effects emerge 1
• Most patients achieve adequate response at 15-30 mg/day in divided doses 1, 4

Target and Maximum Dosing

• Standard target dose: 15-30 mg/day divided into 2-3 doses 1, 4
• Maximum approved dose: 60 mg/day (20 mg three times daily) 1
• Twice-daily dosing (BID) offers equivalent efficacy to three-times-daily (TID) with potentially better compliance 5
• For BID regimen: 15 mg twice daily is standard 5
• For TID regimen: 10 mg three times daily is equivalent 5

Critical Timing Considerations

• Buspirone requires 2-4 weeks to become effective 1
• Patients must be counseled that this is not a rapid-onset anxiolytic like benzodiazepines 2
• Full therapeutic trial requires at least 4-8 weeks at adequate dosing 1
• This delayed onset makes buspirone most appropriate for patients with mild to moderate chronic anxiety who do not require immediate symptom relief 1, 2

Administration Guidelines

• Food significantly affects absorption: administration with food increases peak concentration (Cmax) and AUC by 2-fold 6
• For consistency, administer either always with food or always without food 6
• Rapid absorption occurs with peak plasma levels reached in under 1 hour 6
• Short elimination half-life of approximately 2.5 hours supports divided dosing 6

Special Populations Requiring Dose Adjustment

Hepatic impairment:

• Cmax and AUC increase 15-fold compared to healthy individuals 6
• Half-life doubles in hepatic impairment 6
• Start at lower doses and titrate more cautiously

Renal impairment:

• Cmax and AUC increase 2-fold after single 20 mg dose 6
• Dose reduction and slower titration recommended 6

Elderly patients:

• Pharmacokinetics not significantly affected by age 6
• Standard dosing appropriate, though may start at lower end (5 mg BID) given use in anxious elderly 2

Drug Interactions Requiring Dose Modification

Significant increases in buspirone levels (reduce buspirone dose):

• Verapamil, diltiazem, erythromycin, itraconazole substantially increase buspirone plasma concentrations 6
• Consider starting at 2.5-5 mg BID when combined with these agents

Significant decreases in buspirone levels (may need higher doses):

• Rifampin decreases buspirone concentrations almost 10-fold 6
• May require doses at upper end of range or alternative therapy

Minimal interaction:

• Cimetidine and alprazolam have negligible effects on buspirone levels 6

Common Pitfalls to Avoid

• Do not use buspirone for panic disorder: studies have been inconclusive and it is not recommended for routine panic disorder treatment 2
• Do not expect immediate anxiolytic effects: patients demanding rapid relief are poor candidates 2
• Do not abruptly discontinue after long-term use: although withdrawal syndrome is rare, gradual taper over 10-14 days is prudent when discontinuing after months of therapy 1, 4
• Do not combine with MAO inhibitors: although not detailed in provided evidence, this is a known contraindication
• Monitor for paradoxical agitation: while less common than with benzodiazepines, assess response carefully 1

Monitoring and Reassessment

• Assess therapeutic response at 2-4 weeks minimum 1
• When used for several months or longer, periodically reevaluate the need for continued therapy 4
• After 9 months of treatment, consider dose reduction to reassess necessity of medication 1
• Monitor for most common adverse effects: dizziness, headache, nausea, nervousness, and lightheadedness 3, 5
• Long-term use up to one year has demonstrated no new or unexpected adverse effects beyond those seen in short-term treatment 4