Buspirone Dosing for Generalized Anxiety Disorder
For an adult patient with generalized anxiety disorder and no significant medical history, start buspirone at 5 mg twice daily (10 mg total daily dose), then titrate to a target dose of 15-30 mg per day in divided doses, with a maximum of 60 mg per day if needed. 1
Starting Dose and Titration Schedule
- Initial dose: 5 mg twice daily (BID) 1
- Titration: Increase by 5 mg per day every 2-3 days as tolerated 1
- Target therapeutic range: 15-30 mg per day in divided doses 2, 3
- Maximum dose: 20 mg three times daily (60 mg total daily) 1
Dosing Regimen Options
Two dosing schedules are equally effective and safe: 2
- 15 mg twice daily (BID) - may offer better convenience and compliance 2
- 10 mg three times daily (TID) - traditional dosing 1
The BID regimen showed similar efficacy and tolerability to TID dosing, with the only difference being a slightly higher incidence of palpitations (5% vs 1%) in the BID group 2. Most patients in long-term studies were successfully managed on 15-30 mg daily 3.
Critical Timing Considerations
Buspirone requires 2-4 weeks to become effective, which is a crucial counseling point 1. This delayed onset distinguishes it from benzodiazepines and represents a common pitfall - patients may discontinue prematurely if not properly informed about this timeline.
Important Clinical Caveats
Prior benzodiazepine exposure significantly impacts buspirone efficacy. Patients with chronic benzodiazepine use may not respond adequately to buspirone 4. In one study, buspirone failed to separate from placebo in patients with previous long-term benzodiazepine therapy 4. This is critical for patient selection.
Buspirone is most appropriate for mild to moderate anxiety 1. The guidelines specifically note it is "useful only in patients with mild to moderate agitation" 1.
Pharmacokinetic Profile
- Bioavailability: 3.9% (extensive first-pass metabolism) 5
- Half-life: 2.1 hours for parent compound; 6.1 hours for active metabolite 1-PP 5
- Protein binding: Primarily to albumin and alpha-1-acid glycoprotein 5
The short half-life supports the need for divided dosing throughout the day 5.
Common Adverse Effects
Most frequent side effects include: 1, 2
- Dizziness
- Headache
- Nausea
- Nervousness
- Lightheadedness
These effects are generally mild and occur at low frequency 5, 2. Unlike benzodiazepines, buspirone does not cause significant sedation, psychomotor impairment, or risk of dependence 5, 6.
Long-Term Use
Buspirone can be safely used for up to one year when chronic treatment is necessary 3. In a multicenter trial of 424 patients treated for 6 months and 264 for a full year, no new or unexpected adverse effects emerged with chronic use 3. Importantly, abrupt discontinuation after more than 6 months showed no evidence of withdrawal syndrome 3.