What is the starting dose of Buspar (buspirone) for an adult patient with anxiety?

Buspar Starting Dose for Adult Anxiety

Start buspirone at 5 mg twice daily (total 10 mg/day) and increase by 5 mg/day every 2-3 days until reaching the target therapeutic range of 15-30 mg/day in divided doses. 1

Initial Dosing Algorithm

• Begin with 5 mg twice daily as the standard starting dose for adult patients with generalized anxiety disorder 1
• Titrate upward by 5 mg/day increments every 2-3 days based on tolerability and response 1
• Target the therapeutic range of 15-30 mg/day given in divided doses (typically 2-3 times daily) 1, 2
• Maximum dose is 60 mg/day, though this is rarely needed 1

Critical Timing Expectations

• Buspirone requires 2-4 weeks for full therapeutic effect, making it inappropriate for acute anxiety requiring immediate relief 1
• Do not assess treatment response before 2-4 weeks, as premature discontinuation is a common prescribing error 1
• The delayed onset ("lagtime" of 1-2 weeks) necessitates patient counseling about expectations to maintain compliance 3

Common Prescribing Pitfalls to Avoid

• Never start at too high a dose—this increases side effects without providing faster benefit 1
• Do not discontinue before the 2-4 week therapeutic window has elapsed 1
• Buspirone is only effective for mild-to-moderate generalized anxiety, not for severe agitation or acute panic attacks 1
• Unlike benzodiazepines, buspirone lacks immediate anxiolytic effects and should not be used for breakthrough anxiety 3

Special Population Considerations

• Elderly patients: Buspirone is preferred over benzodiazepines due to lack of sedation, cognitive impairment, and fall risk, with effective doses of 5-30 mg/day (mean 18 mg/day) 1
• Hepatic impairment: Plasma concentrations increase 15-fold with significantly prolonged half-life; dose reduction is necessary 4
• Renal impairment: Plasma concentrations double; dose adjustment required 4

Drug Interactions Requiring Dose Adjustment

• CYP3A4 inhibitors (verapamil, diltiazem, erythromycin, itraconazole) substantially increase buspirone levels and require dose reduction 4
• Rifampin decreases buspirone concentrations nearly 10-fold, potentially requiring dose increases 4
• Food increases bioavailability 2-fold; administer consistently with or without food 4

Long-Term Management

• Most patients are successfully managed on 15-30 mg/day for chronic use 2
• Buspirone can be used safely for up to one year without withdrawal syndrome upon discontinuation 2
• Periodically reevaluate the need for continued therapy when used for several months or longer 2