buspirone (BuSpar, Buspirex, Bustab, LinBuspirone)

Dosing and uses of BuSpar (buspirone)

• Adult
• Pediatric

 

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