Buspirone (buspirone HCl)

For the management of anxiety disorders, the usual initial adult dosage of buspirone hydrochloride is 10-15 mg daily, usually in 2 or 3 divided doses. Dosage is increased as necessary in increments of 5 mg daily every 2-4 days, according to the patient's response and tolerance. In clinical studies, most patients responded to maintenance dosages of 15-30 mg daily in 2 or 3 divided doses. Modification of the usual adult dosage does not appear necessary for geriatric patients. The manufacturer recommends that adult dosage not exceed 60 mg daily.

The manufacturer states that when buspirone is administered concomitantly with a potent CYP3A4 inhibitor, it should be administered at a low dosage (i.e., 2.5 mg once or twice daily) and that subsequent dosage adjustment of either drug should be based on clinical assessment. (See Drug Interactions: Drugs Affecting Microsomal Enzymes and see Dosage and Administration: Administration.)

Buspirone may have a slower onset of action than some anxiolytics (e.g., diazepam), and some patients may require motivation and education about the drug's effects during initial therapy to assure compliance. Symptomatic relief may occur during the first 2 weeks of buspirone therapy in some patients, but optimum anxiolytic effect usually requires at least 3-4 weeks of therapy; occasionally, 4-6 weeks may be required for optimum effect.

The efficacy of continued buspirone therapy for longer than 3-4 weeks has not been established by controlled studies. However, the drug has been used for longer periods (e.g., several months to a year) without unusual adverse effect or decreased efficacy in some patients. If buspirone is administered for longer than 3-4 weeks, the need for continued therapy should be reassessed periodically. Dosage during prolonged maintenance therapy should be kept at the lowest effective level; once an adequate response has been achieved, dosage should be reduced gradually and subsequently adjusted according to the patient's response and tolerance.

Discontinuance of benzodiazepines and some other anxiolytic agents has been associated with symptoms of withdrawal, and buspirone will not prevent the development of these symptoms. Therefore, it is important that therapy with such agents be withdrawn gradually in patients being switched to buspirone, particularly when therapy with one of these agents has been prolonged and/or when relatively high dosages were used.

The need for modification of buspirone hydrochloride dosage in patients with renal impairment has not been fully elucidated, and the drug should be used with caution in such patients. There is some evidence that the pharmacokinetics of buspirone and its active metabolite, 1-pyrimidinylpiperazine (1-PP), are not affected substantially in patients with mild to moderate renal impairment. (See Pharmacokinetics: Elimination) In anuric patients, however, accumulation of 1-PP may occur, and adjustment in buspirone hydrochloride dosage may be necessary. Some clinicians suggest that dosage of the drug be reduced by 25-50% in anuric patients. However, other clinicians state that because of the high interindividual and intraindividual variability in plasma concentrations of buspirone and 1-PP, it is difficult to make dosage adjustment recommendations for patients with renal impairment. Based on results from other studies, several clinicians state that because of the high interindividual and intraindividual variability in plasma buspirone concentrations, dosing recommendations for patients with renal impairment receiving buspirone cannot be made at this time. In addition, the manufacturer states that the drug is not recommended for use in patients with severe renal impairment. The need for supplemental doses during hemodialysis has not been determined, but such doses do not appear necessary since the drug does not appear to be removed substantially by hemodialysis.

Buspirone hydrochloride should be used with caution in patients with impaired hepatic function, and the need for reduced dosage should be considered. (See Pharmacokinetics: Elimination.) The manufacturer states that the drug is not recommended for use in patients with severe hepatic impairment.

Buspirone hydrochloride is administered orally. Concomitant administration of the drug with food can increase oral bioavailability of buspirone. Therefore, the manufacturer states that the drug should be given in a consistent manner relative to food intake. (See Drug Interactions: Food.)

The 15- and 30- mg tablets are provided as Dividose(R) tablets and are scored to be broken in 2 halves (each providing a dose of 7.5 and 15 mg, respectively, or in 3 thirds) (each providing a dose of 5 and 10 mg, respectively).

No dosing information is available for this tab.

No dosing information is available for this tab.

There is no enhanced messaging for this drug.

There are no contraindication interactions for this drug.

There are no severe interactions for this drug.

There are no moderate interactions for this drug.

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

There are no severe contraindications for this drug.

There are no moderate contraindications for this drug.

There is no enhanced messaging for this drug.

There are no severe adverse reactions for this drug.

There are no less severe adverse reactions for this drug.

No enhanced messaging available.

No enhanced messaging available.

Reproduction studies in rats and rabbits using oral buspirone hydrochloride dosages up to 30 times the maximum recommended human dosage have not revealed evidence of fetal abnormality or impaired fertility. There are no adequate and controlled studies to date using buspirone in pregnant women, and the drug should be used during pregnancy only when clearly needed.

The effect of buspirone on labor and delivery in women is not known, but no adverse effects were observed during reproduction studies in animals.

Although the extent of distribution of buspirone and its metabolites into human milk is not known, the drug and its metabolites are distributed into milk in rats. Therefore, the manufacturer recommends that the use of buspirone in nursing women be avoided whenever clinically possible.

No enhanced messaging available.