Drug information of Buspirone

Buspirone

Drug group:

Buspirone is an anti-anxiety medicine that affects chemicals in the brain that may be unbalanced in people with anxiety.
Buspirone is used to treat symptoms of anxiety, such as fear, tension, irritability, dizziness, pounding heartbeat, and other physical symptoms.
Buspirone is not an anti-psychotic medication and should not be used in place of medication prescribed by your doctor for mental illness.

Mechanism of effect

Buspirone 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 effect

Pharmacodynamic

Buspirone is used in the treatment of generalized anxiety where it has advantages over other antianxiety drugs because it does not cause sedation (drowsiness) and does not cause tolerance or physical dependence. Buspirone differs from typical benzodiazepine anxiolytics in that it does not exert anticonvulsant or muscle relaxant effects.
It also lacks the prominent sedative effect that is associated with more typical anxiolytics. in vitro preclinical studies have shown that buspirone has a high affinity for serotonin (5-HT1A) receptors.
Buspirone has no significant affinity for benzodiazepine receptors and does not affect GABA binding in vitro or in vivo when tested in preclinical models. Buspirone has moderate affinity for brain D2-dopamine receptors. Some studies do suggest that buspirone may have indirect effects on other neurotransmitter systems.

Pharmacokinetics

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

Drug indications

Anxiety

Dosage

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

Alerts

• 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). MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, and tranylcypromine.
• This medication can cause false positive results with certain medical tests. You may need to stop using the medicine for at least 48 hours before your test. Tell any doctor who treats you that you are using buspirone.
• Buspirone is not expected to harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Points of recommendation

• You may take buspirone with or without food but take it the same way each time.
• Some buspirone tablets are scored so you can break the tablet into 2 or 3 pieces in order to take a smaller amount of the medicine at each dose .
• This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.
• Drinking alcohol may increase certain side effects of buspirone .
• Grapefruit and grapefruit juice may interact with buspirone and lead to unwanted side effects. Discuss the use of grapefruit products with your doctor.

Pregnancy level

B

Related drugs

Duloxetine , Sertraline


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