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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: Give low dose (eg, 2.5mg qd or bid) cautiously. Periodically reassess usefulness of drug if used for extended periods.

    HOW SUPPLIED

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

    WARNINGS/PRECAUTIONS

    May impair mental/physical abilities. Does not exhibit cross-tolerance with benzodiazepines and other common sedatives/hypnotics; before starting therapy, withdraw gradually from prior treatment, especially in patients using a CNS depressant chronically. May cause acute and chronic changes in dopamine-mediated neurological function; syndrome of restlessness, appearing shortly after initiation, reported. 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.

    ADVERSE REACTIONS

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

    DRUG INTERACTIONS

    See Dosage. Elevated BP reported with MAOI; avoid concomitant use. Avoid with alcohol. Dizziness, headache, nausea, and increased nordiazepam reported with diazepam. May increase serum concentrations of haloperidol. ALT elevations reported with trazodone. Caution with CNS-active drugs. CYP3A4 inhibitors (eg, diltiazem, ketoconazole, ritonavir) may increase concentrations; may require dose adjustment. CYP3A4 inducers (eg, dexamethasone, phenytoin, rifampin), including potent inducers, may decrease concentrations; may require dose adjustment of buspirone. Avoid with large amounts of grapefruit juice. Nefazodone may decrease concentrations of metabolite 1-pyrimidinylpiperazine (1-PP). May increase levels of nefazodone. Cimetidine may increase Cmax and Tmax. 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. Has a 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. (20mg, single dose) Cmax=1-6ng/mL; Tmax=40-90 min. Distribution: Plasma protein binding (86%). Metabolism: Liver (extensive 1st-pass), primarily by oxidation via CYP3A4, and by hydroxylation; 1-PP (active metabolite). Elimination: Urine (29-63%), feces (18-38%); (10-40mg, single dose) 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. Periodically reassess usefulness of drug if used for extended periods.

    PATIENT COUNSELING

    Instruct to inform physician about any medications, prescription or nonprescription, alcohol, or drugs being taken or planning to take, and if patient is pregnant/breastfeeding, becomes pregnant, or is 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.

    ADMINISTRATION/STORAGE

    Administration: Oral route. Take in a consistent manner with regard to the timing of dosing; either always with or always without food. Storage: (5mg, 10mg, 15mg, 30mg) 20-25°C (68-77°F). (7.5mg) 25°C (77°F); excursions permitted between 15-30°C (59-86°F).