What is buspirone (Buspar)? How does it work (mechanism of action)?
Buspirone is a medication that is used for the treatment of anxiety. Its mechanism of action is not clearly understood but may involve effects on neurotransmitters, chemicals that nerves use to communicate with one another. Serotonin and dopamine are two of these neurotransmitters. Buspirone may work by stimulating serotonin type 1A receptors on nerves, thereby altering the chemical messages that nerves receive. It also has minor effects on dopamine receptors but this does not contribute much to its action. Unlike medications for anxiety of the benzodiazepine class, for example, diazepam (Valium), lorazepam (Ativan), alprazolam (Xanax), and clonazepam (Klonopin), buspirone does not cause sedation.
What are the uses for buspirone?
Buspirone is used for the management of anxiety disorders or for the short-term relief of the symptoms of anxiety. Buspirone is especially effective in persons with generalized anxiety of a limited or moderate degree. It is not very effective in persons with severe anxiety, panic disorders, or obsessive-compulsive disorders.
What are the side effects of buspirone?
The most common side effects associated with buspirone are:
Other important but less frequent side effects include
What is the dosage for buspirone?
The usual starting adult dose is 10-15 mg daily given in 2 or 3 doses. The dose may be increased by 5 mg every 2 to 4 days until an effective dose is found. The maximum adult dose is 60 mg daily, but most patients respond to 15-30 mg daily. Although food increases the amount of buspirone that is absorbed, the importance of this effect is not clear. Buspirone can be taken with or without food but preferably on a consistent basis.
Which drugs or supplements interact with buspirone?
Buspirone may interact with drugs called monoamine oxidase (MAO) inhibitors, such as isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), and procarbazine (Matulane) which are used in psychiatric disorders. The use of buspirone with these drugs can cause increased blood pressure. A similar reaction may occur if buspirone is combined with linezolid (Zyvox), an antibiotic that is also an MAO inhibitor. The combination of buspirone and trazodone (Desyrel), an antidepressant, may cause abnormal liver enzymes in the blood.
The combination of buspirone and warfarin (Coumadin), a blood thinner, may accentuate the effects of warfarin and increase the risk of bleeding. Patients taking buspirone should not drink grapefruit juice, since the juice (even well after a dose of buspirone is taken) can increase the amount of buspirone in the blood, possibly leading to side effects.
Inactivation and removal of buspirone is mediated by liver enzymes. Drugs (for example, erythromycin, itraconazole [Sporanox], nefazodone [Serzone]) that inhibit these liver enzyme increase blood concentrations of buspirone, and drugs (for example, rifampin) that enhance these enzymes decrease blood concentrations of buspirone. Increased blood concentrations may increase side effects while decreased blood concentrations may reduce efficacy.
Panic attacks are repeated attacks of fear that can last for several minutes.
Is buspirone safe to take if I’m pregnant or breastfeeding?
- There are no adequate studies of buspirone in pregnant women.
- It is not known if buspirone is secreted in human breast milk. Because buspirone is secreted in the breast milk of animals, however, it should not be used by women who are nursing infants.
What else should I know about buspirone?
What preparations of buspirone are available?
Tablets: 5, 10, 15 and 30 mg.
How should I keep buspirone stored?
Tablets should be kept at room temperature, less than 30 C (86 F).
Buspirone is available as a generic drug, by prescription only.
The FDA approved buspirone in September, 1986.