Buspirone (BuSpar) Dosage for Adults
For adults with anxiety, start buspirone at 5 mg twice daily and titrate up to a typical maintenance dose of 15-30 mg per day, with a maximum of 60 mg per day (20 mg three times daily) if needed. 1, 2
Initial Dosing
- Begin with 5 mg twice daily as recommended by the American Academy of Family Physicians 1, 2
- This conservative starting dose allows assessment of tolerability before escalation 1
Dose Titration
- Gradually increase the dose based on clinical response and tolerability over the first few weeks 2
- Most patients are successfully managed on 15-30 mg per day in divided doses 3, 4
- The typical effective range is 15-30 mg daily, which has been shown to be as effective as benzodiazepines like diazepam and clorazepate 4, 5
Maximum Dosing
- The maximum recommended daily dose is 60 mg per day, typically administered as 20 mg three times daily 1, 2
- Higher doses up to 60 mg daily may be required for optimal therapeutic effect in some patients who do not respond adequately to lower doses 2
Dosing Frequency
- Buspirone can be administered either twice daily (BID) or three times daily (TID) with equivalent efficacy 6
- For a 30 mg daily dose, both 15 mg BID and 10 mg TID regimens show no significant difference in efficacy or safety 6
- The elimination half-life is approximately 2.5 hours, supporting multiple daily dosing 7, 5
Critical Timing Considerations
- Buspirone requires 2-4 weeks to become fully effective for anxiety symptoms 1, 2
- Unlike benzodiazepines, there is a "lag time" of 1-2 weeks before anxiolytic effects become apparent 4
- Patient counseling about this delayed onset is essential to maintain compliance during the initial treatment period 4
Food Effects
- Administration with food increases buspirone absorption 2-fold (both Cmax and AUC) 7
- For consistency, advise patients to take buspirone either always with food or always without food 7
Special Populations
Renal Impairment
- In patients with renal impairment, Cmax and AUC increase 2-fold after a single 20 mg dose 7
- Consider dose reduction or increased monitoring in moderate to severe renal impairment 7
Hepatic Impairment
- In hepatic impairment, buspirone levels increase 15-fold with doubled half-life 7
- Substantial dose reduction is necessary in patients with hepatic disease 7
Elderly Patients
- Pharmacokinetics are not significantly affected by age, so standard dosing applies 7
Long-Term Use
- Buspirone has been studied for up to one year of continuous use without emergence of new adverse effects or withdrawal syndrome upon discontinuation 3
- Most patients in long-term studies were maintained on 15-30 mg daily 3
- When anxiolytic therapy extends beyond several months, periodically reevaluate the need for continued treatment 3
Drug Interactions Requiring Dose Adjustment
- Avoid or reduce dose with CYP3A4 inhibitors: verapamil, diltiazem, erythromycin, and itraconazole substantially increase buspirone plasma concentrations 7
- Rifampin decreases buspirone levels almost 10-fold, potentially requiring dose increases 7
- Cimetidine and alprazolam have negligible effects on buspirone pharmacokinetics 7
Clinical Efficacy Profile
- Buspirone is most effective for mild to moderate anxiety 1
- It is "anxioselective" - lacking the sedative, hypnotic, anticonvulsant, and muscle relaxant properties of benzodiazepines 4, 5
- The drug shows minimal sedation compared to benzodiazepines, making it preferable when daytime alertness is important 4