buspirone (BuSpar, Buspirex, Bustab, LinBuspirone)
Classes: Antianxiety Agents; Anxiolytics, Nonbenzodiazepines
Dosing and uses of BuSpar (buspirone)
Adult dosage forms and strengths
tablet
- 5mg
- 7.5mg
- 10mg
- 15mg
- 30mg
Anxiety Disorders
10-15 mg/day PO divided q8-12hr; may increase every 2-3 days by 5 mg/day to 15-30 mg/day PO divided q8-12hr; not to exceed 60 mg/day
Smoking Cessation (Off-label)
30-60 mg/day PO for 9-13 weeks; begin 2-3 weeks before quit date
Dosing Modifications
Renal impairment: Not recommended for patients with severe impairment
Hepatic impairment: Not recommended for patients with severe impairment
Pediatric dosage forms and strengths
tablet
- 5mg
- 7.5mg
- 10mg
- 15mg
- 30mg
Generalized Anxiety Disorder (Off-label)
Pre-adolescent: 2.5-5 mg PO qDay; may increase dose by 2.5 mg every 3-4 days; not to exceed 20 mg/day
Adolescent: 5-10 mg PO qDay; may increase by 5 mg/day at weekly intervals PRN; not to exceed 60 mg/day divided q8-12hr
Dosing Modifications
Renal impairment: Not recommended for patients with severe impairment
Hepatic impairment: Not recommended for patients with severe impairment
BuSpar (buspirone) adverse (side) effects
>10%
Dizziness (12%)
1-10%
Drowsiness (10%)
Nausea (8%)
Headache (6%)
Nervousness (5%)
Blurred vision (2%)
Confusion (2%)
Diarrhea (2%)
Excitement (2%)
Insomnia (2%)
Myalgia (1%)
Numbness (2%)
Paresthesia (1%)
Rash (1%)
Tremor (1%)
Weakness (2%)
Nasal congestion (1%)
Sore throat (1%)
Nonspecific chest pain (1%)
Tinnitus (1%)
Dream disturbances (1%)
<1%
Akathisia
Allergic reaction
Anorexia
Bruising
Galactorrhea
Heart failure
Menstrual irregularity
Suicidal ideation
Syncope
Alopecia
Eosinophilia
Edema
Enuresis
Increased ocular pressure
Visual disturbances
Rectal bleeding
Photophobia
Dystonia
Warnings
Contraindications
Hypersensitivity
Cautions
Do not use PRN for anxiety
Will not prevent withdrawal from other anxiolytics, such as benzodiazepine
May cause cognitive motor impairment
Restlessness syndrome associated with therapy
Use in severe renal/hepatic impairment not recommended
Use with MAO inhibitors may result in hypertensive reaction (use not recommended)
Pregnancy and lactation
Pregnancy category: B
Lactation: Excretion in milk unknown/not recommended
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of BuSpar (buspirone)
Mechanism of action
Is an azaspirodecanedione; high affinity for serotonin 5HT1A and 5HT2 receptors and moderate affinity for dopamine D2 receptors, but no effect on benzodiazepine GABA receptors
No anticonvulsant, muscle relaxant, or sedative effects
Absorption
Bioavailability: ~4%
Onset: 2-4 wk (anxiolytic effects)
Peak serum time: 40-90 min
Peak plasma concentration: 1-6 ng/mL
Distribution
Protein bound: 86%
Vd: 5.3 L/kg
Metabolism
Hepatic metabolism by CYP3A4
Metabolites: 1-pyrimidinylpiperazine (1-PP)
Elimination
Half-life: 2-3 hr
Excretion: Urine (29-63%); feces (18-38%)
Total body clearance: 28 mL/min/kg