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  • Buspirone
    (Buspirone HCl) - Various

    THERAPEUTIC CLASS

    Atypical anxiolytic

    DEA CLASS

    RX

    INDICATIONS

    Management of anxiety disorders or short-term relief of anxiety symptoms.

    ADULT DOSAGE

    Adults: Initial: 7.5mg bid. Titrate: May increase by 5mg/day at intervals of 2-3 days, PRN. Usual: 20-30mg/day in divided doses. Max: 60mg/day. With Potent CYP3A4 Inhibitor: Low dose given cautiously.

    HOW SUPPLIED

    Tab: 5mg*, 7.5mg*, 10mg*, 15mg*, 30mg* *scored

    WARNINGS/PRECAUTIONS

    May impair mental/physical abilities. Does not exhibit cross-tolerance with benzodiazepine or other common sedatives/hypnotics; withdraw patients gradually from these agents before starting therapy, especially with chronic CNS depressants. May cause acute and chronic changes in dopamine-mediated neurological function; syndrome of restlessness has been reported shortly after initiation. May interfere with urinary metanephrine/catecholamine assay; d/c therapy for at least 48 hrs prior to undergoing urine collection for catecholamines. Not recommended with severe hepatic/renal impairment. Periodically reassess usefulness of drug if used for extended periods.

    ADVERSE REACTIONS

    Dizziness, nausea, headache, nervousness, lightheadedness, excitement, drowsiness, fatigue, insomnia, dry mouth.

    DRUG INTERACTIONS

    Elevation of BP with MAOI reported; avoid concomitant use. Avoid with alcohol. Dizziness, headache, and nausea, and increased nordiazepam reported with diazepam. May increase serum concentrations of haloperidol. ALT elevations reported with trazodone. Caution with CNS-active drugs. Diltiazem, verapamil, erythromycin, grapefruit juice, itraconazole, nefazodone, and other CYP3A4 inhibitors (eg, ketoconazole, ritonavir) may increase concentrations; may require dose adjustment. Rifampin and other CYP3A4 inducers (eg, dexamethasone, phenytoin, phenobarbital, carbamazepine), including potent CYP3A4 inducers, may decrease concentrations; may require dose adjustment. Avoid with large amounts of grapefruit juice. May increase levels of nefazodone. Cimetidine may increase levels. Prolonged PT reported with warfarin. May displace less firmly bound drugs like digoxin.

    PREGNANCY

    Category B, not for use in nursing.

    MECHANISM OF ACTION

    Atypical anxiolytic; has not been established. Binds with high affinity to serotonin (5-HT1A) receptors and moderate affinity for brain D2-dopamine receptors; may have indirect effects on other neurotransmitter systems.

    PHARMACOKINETICS

    Absorption: Rapid. Cmax=1-6ng/mL, Tmax=40-90 min. Distribution: Plasma protein binding (86%). Metabolism: Liver (extensive), primarily by oxidation via CYP3A4, and by hydroxylation; 1-pyrimidinylpiperazine (active metabolite). Elimination: Urine (29-63%), feces (18-38%); T1/2=2-3 hrs.

    ASSESSMENT

    Assess for hypersensitivity to drug, hepatic/renal impairment, pregnancy/nursing status, and possible drug interactions.

    MONITORING

    Monitor for CNS effects, syndrome of restlessness, and other adverse reactions.

    PATIENT COUNSELING

    Instruct to inform physician about any medications, prescription or nonprescription, alcohol, or drugs being taken or planning to take, and if pregnant/breastfeeding, pregnancy occurs, or planning to become pregnant. Advise not to drive a car or operate potentially dangerous machinery until effects have been determined. Instruct to avoid drinking large amounts of grapefruit juice. Advise to take in a consistent manner with regard to timing and food.

    ADMINISTRATION/STORAGE

    Administration: Oral route. Storage: 20-25°C (68-77°F). (7.5mg) 25°C (77°F); excursions permitted between 15-30°C (59-86°F).