buspirone hydrochloride: clinical use

Prescribing considerations

• Confirm that anxiety, rather than depression alone, is the treatment target; buspirone may mask signs of depression and should not be used alone to treat it.
• Review renal and hepatic function, serotonergic medicines, CYP3A4 inhibitors or inducers, alcohol use and sedating medicines.
• Buspirone does not prevent benzodiazepine or sedative-hypnotic withdrawal; establish a supervised withdrawal plan before switching.
• Use particular caution with acute narrow-angle glaucoma, myasthenia gravis, previous drug dependence and non-severe renal or hepatic impairment.
• It is not recommended for children or adolescents because effectiveness has not been established and exposure may be higher than in adults.

Contraindications and cautions

• Hypersensitivity to buspirone or a product excipient
• Epilepsy
• Acute intoxication with alcohol, hypnotics, analgesics or antipsychotics
• Severe renal impairment
• Severe hepatic impairment
• Rare hereditary galactose intolerance, total lactase deficiency or glucose-galactose malabsorption because the selected product contains lactose

Monitoring

• Assess anxiety symptoms, function, adherence and adverse effects such as dizziness, drowsiness or agitation.
• Watch for serotonin toxicity when serotonergic medicines are co-prescribed, particularly after treatment changes.
• Review renal or hepatic status where impairment is present.
• Consider anticoagulation monitoring with warfarin and liver tests if clinically indicated with trazodone.
• Assess driving and occupational safety where dizziness, drowsiness or impaired coordination occurs.

Clinical pharmacology

Buspirone is an azapirone anxiolytic with presynaptic agonist and postsynaptic partial agonist activity at 5-HT1A receptors. It also has D2 antagonist activity of uncertain clinical relevance. It undergoes extensive first-pass metabolism, principally through CYP3A4, producing an active 1-pyrimidinylpiperazine metabolite; elimination is mainly through urine and bile as metabolites.

Formulation and product differences

• The selected product is a white, uncoated, ovoid rectangular tablet with a score line.
• It contains lactose monohydrate and is essentially sodium-free.
• It is supplied in blister packs; not every authorised pack size may be marketed.
• The selected product information does not state that the score line divides the tablet into equal portions.

Tablet

Route: Oral

Strengths: 5 mg, 7.5 mg, 10 mg