buspirone, Buspar (Discontinued brand in the US)
Omudhome Ogbru, PharmD
Omudhome Ogbru, PharmD
Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.
Medical and Pharmacy Editor:
GENERIC NAME: buspirone
BRAND NAME: Buspar (Discontinued brand in the US)
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. The FDA approved buspirone in September 1986.
GENERIC AVAILABLE: Yes
PREPARATIONS: Tablets: 5, 10, 15 and 30 mg.
STORAGE: Tablets should be kept at room temperature, less than 30 C (86 F).
PRESCRIBED FOR: 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. It also may help improve symptoms of depression in patients with generalized anxiety disorder.
DOSING: 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.
DRUG INTERACTIONS: 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.
PREGNANCY: There are no adequate studies of buspirone in pregnant women.
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