buspirone, Buspar (Discontinued brand in the US) (cont.)

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Medical and Pharmacy Editor:

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.

NURSING MOTHERS: 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.

Medically Reviewed by a Doctor on 12/10/2013


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