What is the appropriate dosing regimen for buspirone (Buspar) in adults, including starting dose, titration schedule, maximum dose, and special considerations for older adults or hepatic impairment?

Buspirone (Buspar) Dosing

For adults with generalized anxiety disorder, initiate buspirone at 15 mg per day divided into two or three doses (e.g., 7.5 mg twice daily or 5 mg three times daily), then titrate upward by 5 mg every 2–3 days as tolerated to a target dose of 20–30 mg per day, with a maximum of 60 mg per day in divided doses. 1

Starting Dose and Initial Titration

• Begin with 15 mg per day divided into 2–3 doses (most commonly 7.5 mg twice daily), which represents the standard starting dose for generalized anxiety disorder 1
• Increase the dose by 5 mg per day every 2–3 days based on clinical response and tolerability 1
• Most patients achieve therapeutic benefit at 15–30 mg per day, which is the typical maintenance range used in long-term studies 2

Target and Maximum Dosing

• The usual effective dose is 20–30 mg per day in divided doses, which was the mean daily dose in a 52-week safety trial 2
• The maximum recommended dose is 60 mg per day divided into 2–3 doses, though doses above 30 mg are rarely needed 1
• Divide the total daily dose into 2–3 administrations throughout the day to maintain therapeutic plasma levels, given buspirone's short elimination half-life of approximately 2.5 hours 3

Dosing Schedule Considerations

• Administer doses at consistent intervals (e.g., 9 AM and 9 PM for twice-daily dosing) rather than uneven spacing, because the drug's 2.5-hour half-life requires regular dosing to maintain steady plasma concentrations 4
• Take with or without food consistently—food increases buspirone bioavailability approximately 2-fold, so patients should maintain the same pattern (always with food or always without) to ensure stable drug levels 3
• Unlike benzodiazepines, buspirone causes minimal sedation and does not require specific timing to prevent sleep disturbances 4

Special Populations

Older Adults

• No dose reduction is required based on age alone, as pharmacokinetics are not significantly affected by age 3
• Use the same starting dose (15 mg per day) and titration schedule as younger adults 3

Hepatic Impairment

• Reduce the starting dose to 5 mg twice daily (10 mg per day total) in patients with compensated or decompensated liver disease 5
• Titrate more slowly and cautiously, as buspirone plasma concentrations are 15-fold higher and the half-life is twice as long in hepatic impairment compared to healthy individuals 3
• Monitor closely for adverse effects and consider a lower maximum dose 5

Renal Impairment

• Reduce the starting dose to 5 mg twice daily (10 mg per day total) in patients with moderate to severe renal impairment 5
• Peak concentrations and drug exposure are 2-fold higher in renal impairment after a single dose 3
• Titrate cautiously and monitor for increased side effects 5

Time to Therapeutic Effect

• Full anxiolytic effect requires 2–4 weeks of consistent dosing at an adequate dose, unlike benzodiazepines which work immediately 1
• Patients should be counseled that buspirone is not effective for acute anxiety or "as-needed" use 1
• Reassess the need for continued therapy after several months of treatment, as long-term anxiolytic therapy should be periodically reevaluated 2

Duration of Therapy

• Buspirone has been studied for up to 52 weeks of continuous use without emergence of new safety concerns, withdrawal symptoms upon abrupt discontinuation, or evidence of tolerance 2
• When therapy extends beyond 6 months, periodically reassess whether continued treatment is necessary 2
• No tapering is required when discontinuing buspirone, even after prolonged use, as it does not produce physiologic dependence or withdrawal syndrome 2, 1

Common Pitfalls to Avoid

• Do not prescribe buspirone for acute anxiety relief—it takes 2–4 weeks to work and has no immediate anxiolytic effect 1
• Do not use "as needed" dosing—buspirone requires consistent twice- or three-times-daily administration to maintain therapeutic levels 3
• Do not combine with strong CYP3A4 inhibitors (e.g., itraconazole, erythromycin, verapamil, diltiazem) without dose reduction, as these drugs substantially increase buspirone plasma concentrations 3
• Avoid rifampin co-administration, which decreases buspirone levels nearly 10-fold and renders it ineffective 3
• Counsel patients about food consistency—taking buspirone sometimes with food and sometimes without causes unpredictable fluctuations in drug levels 3

Adverse Effects

• The most common side effects are dizziness, nervousness, and headache, which are generally mild 1
• Buspirone lacks sedation, muscle relaxation, anticonvulsant effects, alcohol interaction, driving impairment, and abuse potential that characterize benzodiazepines 1
• No physiologic dependence develops with chronic use 1