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BusPIRone

Medically reviewed by Drugs.com. Last updated on Nov 9, 2020.

Pronunciation

(byoo SPYE rone)

Index Terms

BuSpar
Buspirone Hydrochloride

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet, Oral, as hydrochloride:

Generic: 5 mg, 7.5 mg, 10 mg, 15 mg, 30 mg

Pharmacologic Category

Antianxiety Agent, Miscellaneous

Pharmacology

The mechanism of action of buspirone is unknown. Buspirone has a high affinity for serotonin 5-HT_1A and 5-HT₂ receptors, without affecting benzodiazepine-GABA receptors. Buspirone has moderate affinity for dopamine D₂ receptors.

Absorption

Rapid and complete; bioavailability is limited by extensive first-pass effect; only ~1% of the oral dose reaches the systemic circulation unchanged

Distribution

V_d: 5.3 L/kg (Gammans 1986)

Metabolism

Hepatic oxidation, primarily via CYP3A4 to several metabolites including an active metabolite, 1-pyrimidinylpiperazine (1-PP; exhibits about 25% of the activity of buspirone); extensive first-pass effect

Excretion

Urine: 29% to 63% (primarily as metabolites); feces: 18% to 38%

Time to Peak

Serum: 40 to 90 minutes

Half-Life Elimination

2 to 3 hours; increased with renal or hepatic impairment

Protein Binding

~86%

Special Populations: Renal Function Impairment

AUC increased 4-fold.

Special Populations: Hepatic Function Impairment

AUC increased 13-fold.

Use: Labeled Indications

Generalized anxiety disorder: Management of generalized anxiety disorder or the short-term relief of the symptoms of anxiety

Off Label Uses

Unipolar depression, augmentation

Data from two randomized controlled trials in patients with nonpsychotic major depressive disorder without remission despite treatment with an SSRI (ie, citalopram and fluoxetine) support the use of buspirone as an augmentation strategy in the treatment of this condition. However, in comparison to bupropion, patients receiving buspirone had more adverse effects and less improvement in symptoms ^{[Appelberg 2001]}, ^{[Trivedi 2006]}. Additional trials may be necessary to further define the role of buspirone in this condition.

Based on the American Psychiatric Association (APA) practice guideline for the treatment of patients with major depressive disorder, buspirone (added to an SSRI) is an effective augmentation strategy for this condition.

Contraindications

Hypersensitivity to buspirone or any component of the formulation; concomitant use of monoamine oxidase inhibitors (MAOIs) intended to treat depression or within 14 days of discontinuing MAOIs intended to treat depression; concomitant use of MAOIs within 14 days of discontinuing buspirone; initiation of buspirone in patients receiving reversible MAOIs (eg, linezolid, IV methylene blue).

Canadian labeling: Additional contraindications not in US labeling: Severe hepatic or severe renal impairment.

Dosing: Adult

Note: Periodically assess the usefulness of the drug for the individual patient.

Generalized anxiety disorder: Oral: Initial: 10 to 15 mg/day in 2 to 3 divided doses; may increase every 2 to 3 days in increments of 5 mg/day to a maximum of 60 mg/day; usual dose: 20 to 30 mg/day in 2 to 3 divided doses (Chessick 2006; Sramek 1999).

Unipolar depression, augmentation (alternative agent following antidepressant switch and other augmentation agents) (off-label use): Oral: Initial: 15 to 20 mg/day in 2 divided doses; may increase every 3 to 7 days in increments of 10 to 15 mg/day to a maximum of 60 mg/day in 2 divided doses (APA 2010; Appelberg 2001; Trivedi 2006).

Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Anxiety disorders: Children ≥6 years and Adolescents: Limited data available; dose and efficacy not well established: Oral: Initial dose: 5 mg once daily; may increase by 5 mg/day every 2 to 7 days as tolerated; usual dose range: 7.5 to 30 mg twice daily (Simeon 1994; Strawn 2018; manufacturer's labeling).

Dosing based on open-label and placebo-controlled trials. One open pilot study of 15 children (mean age: 10 years [range: 6 to 14 years]) with mixed anxiety disorders (per DSM III-R criteria) used an initial dose of 5 mg daily; doses were titrated by increments of 5 mg/day every week as needed to a maximum dose of 20 mg/day divided into 2 doses; mean dose required: 18.6 mg/day (Simeon 1994). Two placebo-controlled 6-week trials in children and adolescents (n=559; age: 6 to 17 years) with generalized anxiety disorder evaluated doses of 7.5 to 30 mg twice daily (15 to 60 mg/day); no significant differences between buspirone and placebo with respect to generalized anxiety disorder symptoms were observed (manufacturer's labeling). A 2018 analysis of these abandoned trials reported that buspirone did not separate from placebo; however, the studies may have been underpowered to detect small differences, suggesting that the studies neither support nor refute the utility of buspirone. The dropout rate due to adverse reactions in the studies was higher for buspirone (Strawn 2018).

Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.

Administration

Oral: Administer with or without food, but must be consistent.

Dietary Considerations

Avoid large quantities of grapefruit juice.

Storage

Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C to 30°C (59°F to 86°F). Protect from light.

Drug Interactions

Abametapir: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Avoid combination

Alcohol (Ethyl): BusPIRone may enhance the sedative effect of Alcohol (Ethyl). Avoid combination

Aprepitant: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Calcium Channel Blockers (Nondihydropyridine): May increase the serum concentration of BusPIRone. Monitor therapy

Clofazimine: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Conivaptan: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Avoid combination

CYP3A4 Inducers (Moderate): May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

CYP3A4 Inducers (Strong): May decrease the serum concentration of BusPIRone. Management: Consider alternatives to this combination. If coadministration of these agents is deemed necessary, monitor patients for reduced buspirone effects and increase buspirone doses as needed. Consider therapy modification

CYP3A4 Inhibitors (Moderate): May decrease the metabolism of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

CYP3A4 Inhibitors (Strong): May increase the serum concentration of BusPIRone. Management: Limit the buspirone dose to 2.5 mg daily and monitor patients for increased buspirone effects/toxicities if combined with strong CYP3A4 inhibitors. Consider therapy modification

Dabrafenib: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Seek alternatives to concomitant therapy when possible. If concomitant therapy cannot be avoided, monitor for reduced clinical effects of the CYP3A4 substrate. Consider therapy modification

Deferasirox: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Duvelisib: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Enzalutamide: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Concurrent use of enzalutamide with CYP3A4 substrates that have a narrow therapeutic index should be avoided. Use of enzalutamide and any other CYP3A4 substrate should be performed with caution and close monitoring. Consider therapy modification

Erdafitinib: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Erdafitinib: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Erythromycin (Systemic): May increase the serum concentration of BusPIRone. Management: Limit the buspirone dose to 2.5 mg twice daily and monitor for increased buspirone effects/toxicities if combined with erythromycin. Consider therapy modification

Fenfluramine: May enhance the serotonergic effect of Serotonergic Agents (Moderate Risk, Miscellaneous). This could result in serotonin syndrome. Monitor therapy

Fosaprepitant: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Fosnetupitant: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Fusidic Acid (Systemic): May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Avoid combination

Grapefruit Juice: May increase the serum concentration of BusPIRone. Management: Monitor for increased effect of buspirone if combined with grapefruit juice. Patients should avoid consuming large quantities of grapefruit juice. Consider therapy modification

Idelalisib: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Avoid combination

Ioflupane I 123: BusPIRone may diminish the diagnostic effect of Ioflupane I 123. Monitor therapy

Ivosidenib: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Larotrectinib: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Linezolid: BusPIRone may enhance the serotonergic effect of Linezolid. This could result in serotonin syndrome. Avoid combination

Lorcaserin (Withdrawn From US Market): May enhance the serotonergic effect of Serotonergic Agents (Moderate Risk, Miscellaneous). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Monitor therapy

Methylene Blue: BusPIRone may enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Avoid combination

MiFEPRIStone: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Management: Minimize doses of CYP3A4 substrates, and monitor for increased concentrations/toxicity, during and 2 weeks following treatment with mifepristone. Avoid cyclosporine, dihydroergotamine, ergotamine, fentanyl, pimozide, quinidine, sirolimus, and tacrolimus. Consider therapy modification

Mitotane: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Management: Doses of CYP3A4 substrates may need to be adjusted substantially when used in patients being treated with mitotane. Consider therapy modification

Monoamine Oxidase Inhibitors (Antidepressant): BusPIRone may enhance the serotonergic effect of Monoamine Oxidase Inhibitors (Antidepressant). This could result in serotonin syndrome. Avoid combination

Monoamine Oxidase Inhibitors (Type B): May enhance the serotonergic effect of Serotonergic Agents (Moderate Risk, Miscellaneous). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Monitor therapy

Nefazodone: BusPIRone may enhance the serotonergic effect of Nefazodone. This could result in serotonin syndrome. Nefazodone may increase the serum concentration of BusPIRone. Management: Limit the buspirone dose to 2.5 mg daily and monitor patients for increased buspirone effects/toxicities, including serotonin syndrome, if combined with nefazodone. Consider therapy modification

Netupitant: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Oxitriptan: May enhance the serotonergic effect of Serotonergic Agents (Moderate Risk, Miscellaneous). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Monitor therapy

Palbociclib: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

Resveratrol: May increase the serum concentration of BusPIRone. Monitor therapy

Sarilumab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Serotonergic Agents (High Risk): BusPIRone may enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Monitor therapy

Siltuximab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Simeprevir: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Monitor therapy

St John's Wort: BusPIRone may enhance the serotonergic effect of St John's Wort. This could result in serotonin syndrome. St John's Wort may decrease the serum concentration of BusPIRone. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) and for reduced buspirone efficacy when these agents are combined. Monitor therapy

Stiripentol: May increase the serum concentration of CYP3A4 Substrates (High risk with Inhibitors). Management: Use of stiripentol with CYP3A4 substrates that are considered to have a narrow therapeutic index should be avoided due to the increased risk for adverse effects and toxicity. Any CYP3A4 substrate used with stiripentol requires closer monitoring. Consider therapy modification

Tocilizumab: May decrease the serum concentration of CYP3A4 Substrates (High risk with Inducers). Monitor therapy

Yohimbine: May diminish the therapeutic effect of Antianxiety Agents. Monitor therapy

Test Interactions

The presence of buspirone may result in a false positive on a urinary assay for metanephrine/catecholamine; discontinue buspirone ≥48 hours prior to collection of urine sample for catecholamines.

Adverse Reactions

The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.

>10%: Central nervous system: Dizziness (3% to 12%)

1% to 10%:

Cardiovascular: Chest pain (≥1%)

Central nervous system: Drowsiness (10%), headache (6%), nervousness (5%), confusion (2%), excitement (2%), numbness (2%), outbursts of anger (2%), abnormal dreams (≥1%), ataxia (1%) paresthesia (1%)

Dermatologic: Diaphoresis (1%), skin rash (1%)

Gastrointestinal: Nausea (8%), diarrhea (2%), sore throat (≥1%)

Neuromuscular & skeletal: Weakness (2%), musculoskeletal pain (1%), tremor (1%)

Ophthalmic: Blurred vision (2%)

Otic: Tinnitus (≥1%)

Respiratory: Nasal congestion (≥1%)

<1%, postmarketing, and/or case reports: Acne vulgaris, akathisia, alcohol abuse, alopecia, altered sense of smell, amenorrhea, angioedema, anorexia, apathy, arthralgia, bradycardia, bruise, cardiac failure, cardiomyopathy, cerebrovascular accident, change in libido, claustrophobia, cogwheel rigidity, cold intolerance, conjunctivitis, delayed ejaculation, depersonalization, dissociative reaction, dysgeusia, dyskinesia, dysphoria, dyspnea, dystonia, dysuria, edema, emotional lability, eosinophilia, epistaxis, euphoria, extrapyramidal reaction, eye pain, facial edema, fear, fever, flatulence, flushing, galactorrhea, glossopyrosis, hallucination, hemorrhagic diathesis, hiccups, hyperacusis, hypersensitivity reaction, hypertension, hyperventilation, hypotension, impotence, increased appetite, increased intraocular pressure, increased serum ALT, increased serum AST, increased serum transaminases, inner ear disturbance, involuntary muscle movements, irritable bowel syndrome, laryngitis, leukopenia, malaise, memory impairment, menstrual disease, muscle cramps, muscle spasm, myocardial infarction, nocturia, parkinsonian-like syndrome, pelvic inflammatory disease, personality disorder, photophobia, pruritus, psychosis, rectal hemorrhage, restless leg syndrome, restlessness, roaring sensation in head, salivation, seizure, serotonin syndrome, skin blister, slowed reaction time, slurred speech, stiffness, stupor, suicidal ideation, syncope, thinning of nails, thrombocytopenia, thyroid disease, urinary frequency, urinary hesitancy, urinary incontinence, urinary retention, urticaria, vertigo, visual disturbance (tunnel vision), weight gain, weight loss, xeroderma

Warnings/Precautions

Concerns related to adverse effects:

• Akathisia: Akathisia, or restlessness, has been reported in small number of patients; may be a result of central dopamine receptor antagonism. Monitor for signs of any dopamine-related movement disorders (eg, dystonia, akathisia, pseudo-parkinsonism, tardive dyskinesia).

• CNS depression: May rarely cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery or driving).

• Serotonin syndrome: Potentially life-threatening serotonin syndrome has occurred with serotonergic agents, including buspirone, particularly when used in combination with other serotonergic agents (eg, triptans, TCAs, fentanyl, lithium, tramadol, buspirone, St John's wort, tryptophan) or agents that impair metabolism of serotonin (eg, MAOIs intended to treat psychiatric disorders, other MAOIs [ie, linezolid and IV methylene blue]). Monitor patients closely for signs of serotonin syndrome, such as mental status changes (eg, agitation, hallucinations, delirium, coma); autonomic instability (eg, tachycardia, labile blood pressure, diaphoresis, flushing, hyperthermia); neuromuscular changes (eg, tremor, rigidity, myoclonus); GI symptoms (eg, nausea, vomiting, diarrhea); and/or seizures. Discontinue treatment (and any concomitant serotonergic agent) immediately if signs/symptoms arise.

Disease-related concerns:

• Hepatic impairment: Use caution in patients with hepatic impairment; use in severe hepatic impairment is not recommended.

• Renal impairment: Use caution in patients with renal impairment; use in severe renal impairment is not recommended.

Other warnings/precautions:

• Sedative/hypnotic withdrawal: Buspirone does not exhibit cross-tolerance with benzodiazepines or other sedative/hypnotic agents. If substituting buspirone for any of these agents, gradually withdraw the drug(s) prior to initiating buspirone.

Monitoring Parameters

Mental status, symptoms of anxiety, signs/symptoms of serotonin syndrome.

Pregnancy Risk Factor

Pregnancy Considerations

Adverse events have not been observed in animal reproduction studies.

Patient Education

What is this drug used for?

• It is used to treat anxiety.

• It may be given to you for other reasons. Talk with the doctor.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Fatigue

• Dizziness

• Anxiety

• Headache

• Nausea

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Serotonin syndrome like dizziness, severe headache, agitation, sensing things that seem real but are not, fast heartbeat, abnormal heartbeat, flushing, tremors, sweating a lot, change in balance, severe nausea, or severe diarrhea.

• Agitation

• Abnormal movements

• Twitching

• Change in balance

• Trouble speaking

• Trouble swallowing

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.