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  • Buspirone
    (buspirone hydrochloride)

    OTHER BRAND NAMES

    Buspar (Discontinued)

    THERAPEUTIC CLASS

    Atypical anxiolytic

    DEA CLASS

    RX

    INDICATIONS

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

    ADULT DOSAGE

    Anxiety Disorders

    Management of Disorders or Short-Term Relief of Symptoms:
    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

    Periodically reassess usefulness of drug if used for extended periods

    DOSING CONSIDERATIONS

    Renal Impairment
    Severe: Not recommended

    Hepatic Impairment
    Severe: Not recommended

    ADMINISTRATION

    Oral route

    Take in a consistent manner w/ regard to the timing of dosing; either always w/ or always w/o food

    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 AND LACTATION

    Category B, not for use in nursing.

    MECHANISM OF ACTION

    Atypical anxiolytic; has not been established. Has a high affinity to 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 patient is taking 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.

    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).