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Buspirone (BuSpar)

Anxiolyticprescriptionoral · inferred

Non-benzodiazepine anxiolytic (5-HT1A partial agonist) for generalized anxiety disorder. Takes 2-4 weeks for full effect. Metabolized by CYP3A4 to active metabolite 1-PP (alpha-2 adrenergic antagonist). No sedation, dependence, or withdrawal. Not effective PRN for acute anxiety.

Projected serum levels — 10 mg, twice daily

Buspirone (BuSpar)
Buspirone (BuSpar) modeled serum levels, 10 mg twice daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 7 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 10 mg twice daily (oral).

Modeled steady state after ~1 days: peak ≈ 0.32 mg, trough ≈ 0.016 mg body load. Population-based estimate over 15 days for a 10 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Anxiolytic
Route modeled
Oral
Model confidence
inferred
Half-life
2.5 h
Common dose
10 mg
Suggested maximum
60 mg/day
Reference dose range
5–60 mg (single dose)
Suggested cadence
twice daily
Validated against
10 mg oral — Cmax 0.002 mg/L at 0.75 h

Documented interactions

  • contraindicated
    Carbamazepine (Tegretol) + Buspirone (BuSpar) CYP induction

    Carbamazepine (Tegretol) inducer of CYP3A4 predicted to change Buspirone (BuSpar) AUC by ~0.20x

  • contraindicated
    Clarithromycin (Biaxin) + Buspirone (BuSpar) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Buspirone (BuSpar) AUC by ~10.00x

  • contraindicated
    Dasatinib (Sprycel) + Buspirone (BuSpar) CYP inhibition

    Dasatinib (Sprycel) time_dependent_inhibitor of CYP3A4 predicted to change Buspirone (BuSpar) AUC by ~5.00x

  • contraindicated
    Diltiazem + Buspirone (BuSpar) CYP inhibition

    Diltiazem mechanism_based of CYP3A4 predicted to change Buspirone (BuSpar) AUC by ~10.00x

  • contraindicated
    Efavirenz (Sustiva) + Buspirone (BuSpar) CYP induction

    Efavirenz (Sustiva) inducer of CYP3A4 predicted to change Buspirone (BuSpar) AUC by ~0.12x

  • contraindicated
    Grapefruit (whole fruit) + Buspirone (BuSpar) CYP inhibition

    Grapefruit (whole fruit) mechanism_based of CYP3A4 predicted to change Buspirone (BuSpar) AUC by ~10.00x

Serum checks 172 modeled interaction pairings for buspirone (buspar) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Use of buspirone in patients with generalized anxiety disorder and coexisting depressive symptoms: a meta-analysis of eight randomized controlled studies Gammans RE et al. · Neuropsychobiology, 1992 DOI

    Meta-analysis of 8 RCTs (520 GAD patients) showing buspirone significantly improved HAM-A anxiety scores and global improvement compared to placebo, with concurrent improvement in depressive symptoms.

  2. Assessment of the efficacy of buspirone in patients affected by generalized anxiety disorder, shifting from prior lorazepam: a placebo-controlled, double-blind study Delle Chiaie R et al. · European Psychiatry, 1995 DOI

    Double-blind RCT demonstrating buspirone was more effective than placebo and comparable to lorazepam for GAD, without rebound anxiety or withdrawal syndrome upon discontinuation.

  3. Clinical pharmacokinetics and pharmacodynamics of buspirone, an anxiolytic drug Mahmood I, Sahajwalla C · Clinical Pharmacokinetics, 1999 DOI

    Comprehensive PK/PD review establishing buspirone half-life of 2-3 hours, extensive CYP3A4 metabolism, active metabolite 1-PP with alpha-2 antagonist activity, and high interindividual variability.

3 published studies referenced in the app, each with a plain-language summary.