Buspirone (BuSpar®): Basic Information

Buspirone (formerly brand name BuSpar® in the US, which has now been discontinued) is an anxiolytic with a unique mechanism of action and not related chemically or pharmacologically to benzodiazepines or barbiturates.

Buspirone is a partial agonist at post-synaptic serotonin 1A receptors and a full agonist at pre-synaptic serotonin 1A receptors.

FDA-approved indications

1. Management of Generalized Anxiety Disorder
2. Short-term relief of symptoms of anxiety

Dosage

Initial: 15 mg daily (7.5 mg twice daily)

Titration: The dose may be increased 5 mg per day at intervals of 2 to 3 days

Maximum: 60 mg daily

General Instructions: Patients should take buspirone in a consistent manner with regard to the timing of dosing; either always with or always without food.

Precautions:
1. Avoid concurrent administration with monoamine oxidase inhibitors (MAOIs) since it may lead to an increase in blood pressure.
2. Avoid in patients with severe hepatic or renal impairment.

Dosage forms and strengths

Note: Buspirone is no longer available in the US as brand name BuSpar®

Tablets (generic) are available in the following strengths:

5 mg (scored)

7.5 mg (scored)

10 mg (scored)

15 mg (multi-scored, bisected or trisected; can be broken into either two or three parts. Can provide either 5 mg, 7.5 mg, or 15 mg)

30 mg (multi-scored, bisected or trisected; can be broken into either two or three parts. Can provide either 10 mg, 15 mg, or 30 mg)

Drug-drug interactions

Buspirone is metabolized by cytochrome P450 3A4.

Drugs or other factors that induce CYP3A4 decrease the serum levels of buspirone, e.g., carbamazepine, phenytoin, St. John’s Wort

Drugs or other factors that inhibit CYP3A4 increase the serum levels of buspirone, e.g., grapefruit juice.

Buspirone does not significantly induce or inhibit any cytochrome P450 enzyme.

Side effects

Please see this page for a handout listing the common and less common side effects of buspirone along with the percentages of patients who report them.

Important! Please refer to the full Prescribing Information (see link below) before prescribing this medication.

Related Pages

Can buspirone cause dyskinesia or parkinsonism?

Serotonin syndrome with a combination of buspirone and a serotonergic antidepressant?

References

Buspirone Prescribing Information

Drug Interactions Flockhart Table™

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