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Buspirone: Drug information

Buspirone: Drug information
(For additional information see "Buspirone: Patient drug information" and see "Buspirone: Pediatric drug information")

For abbreviations, symbols, and age group definitions used in Lexicomp (show table)
Brand Names: Canada
  • APO-BusPIRone;
  • AURO-Buspirone;
  • CO BusPIRone;
  • GMD-Buspirione;
  • JAMP-Buspirone;
  • MINT-Buspirone;
  • PMS-BusPIRone;
  • TEVA-BusPIRone
Pharmacologic Category
  • Antianxiety Agent, Miscellaneous
Dosing: Adult

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

Generalized anxiety disorder

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 (Ref).

Unipolar depression, augmentation

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 (Ref).

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

Dosing: Kidney Impairment: Adult

The renal dosing recommendations are based upon the best available evidence and clinical expertise. Senior Editorial Team: Bruce Mueller, PharmD, FCCP, FASN, FNKF; Jason A. Roberts, PhD, BPharm (Hons), B App Sc, FSHP, FISAC; Michael Heung, MD, MS.

Altered kidney function:

CrCl ≥60 mL/minute: No dosage adjustment necessary.

CrCl <60 mL/minute: No specific dose adjustments can be recommended due to the high interindividual variability in reported AUC and half-life of buspirone and its active metabolite; however, mean plasma concentrations of buspirone and its active metabolite are significantly elevated compared to subjects with normal kidney function. Thus, it is reasonable to start with low daily doses (eg, 5 mg twice daily); titrate cautiously based on response and tolerability with close monitoring for adverse effects (Ref).

Hemodialysis, intermittent (thrice weekly): Unlikely to be significantly dialyzable (86% protein bound) (Ref):

No specific dose adjustments can be recommended due to the high interindividual variability in reported AUC and half-life of buspirone and its active metabolite; however, mean plasma concentrations of buspirone and its active metabolite are significantly elevated in patients on hemodialysis compared to subjects with normal kidney function. Thus, it is reasonable to start with low daily doses (eg, 2.5 to 5 mg twice daily); titrate cautiously based on response and tolerability with close monitoring for adverse effects (Ref). Limiting the total daily dose to 30 to 45 mg/day has been suggested (Ref).

Peritoneal dialysis: Unlikely to be significantly dialyzable (86% protein bound) (Ref):

No specific dose adjustments can be recommended due to the high interindividual variability in reported AUC and half-life of buspirone and its active metabolite; however, mean plasma concentrations of buspirone and its active metabolite are significantly elevated in patients with end-stage kidney disease compared to subjects with normal kidney function. Thus, it is reasonable to start with low daily doses (eg, 2.5 to 5 mg twice daily); titrate cautiously based on response and tolerability with close monitoring for adverse effects (Ref). Limiting the total daily dose to 30 to 45 mg/day has been suggested (Ref).

CRRT: Use with caution (has not been studied); interindividual pharmacokinetic variability is likely significant, and critically ill patients may have concomitant liver dysfunction and altered protein binding. Start with low daily doses (eg, 5 mg twice daily); titrate cautiously based on response and tolerability with close monitoring for adverse effects (Ref).

PIRRT (eg, sustained, low-efficiency diafiltration): Use with caution (has not been studied); interindividual pharmacokinetic variability is likely significant, and critically ill patients may have concomitant liver dysfunction and altered protein binding. Start with low daily doses (eg, 5 mg twice daily); titrate cautiously based on response and tolerability with close monitoring for adverse effects (Ref).

Dosing: Hepatic Impairment: Adult

Mild to moderate impairment: There are no dosage adjustments provided in the manufacturer’s labeling; use with caution (these patients demonstrated increased plasma levels and a prolonged half-life of buspirone).

Severe impairment: Use not recommended.

Dosing: Pediatric

(For additional information see "Buspirone: Pediatric drug information")

Anxiety disorders

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 (Ref).

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 (Ref). 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 (Ref). 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 (Ref).

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

Dosing: Kidney Impairment: Pediatric

Patients with impaired renal function demonstrated increased plasma levels and a prolonged half-life of buspirone. Use in patients with severe renal impairment not recommended.

Dosing: Hepatic Impairment: Pediatric

Patients with impaired hepatic function demonstrated increased plasma levels and a prolonged half-life of buspirone. Use in patients with severe hepatic impairment not recommended.

Dosing: Older Adult

Refer to adult dosing.

Dosage Forms: US

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

Generic Equivalent Available: US

Yes

Dosage Forms: Canada

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

Tablet, Oral, as hydrochloride:

Generic: 5 mg, 10 mg

Administration: Adult

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

Administration: Pediatric

Oral: Administer in a consistent manner in relation to food (ie, either always with food or always without food).

Use: Labeled Indications

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

Use: Off-Label: Adult

Unipolar depression, augmentation

Medication Safety Issues
Sound-alike/look-alike issues:

BusPIRone may be confused with buPROPion

Adverse Reactions (Significant): Considerations
CNS effects

Although CNS effects are uncommon with use, with the possible exception of dizziness, buspirone has been associated with some mild to moderate CNS effects such as headache, nervousness, excitement, and to a lesser degree, drowsiness and insomnia. Data suggest that stimulant effects (eg, nervousness, dizziness, excitement) are more likely to occur than sedative effects (Ref). Data also suggest that buspirone has limited effects on performance function (Ref).

Mechanism: Dose-related; mechanism has not been fully elucidated, but it is believed that buspirone acts as a serotonin (5-HT1A) partial agonist and has moderate affinity for dopamine D2 receptors in the brain. Buspirone has been shown to increase the spontaneous firing of noradrenergic neurons in the locus ceruleus in a dose-dependent manner, stimulating central sympathomimetic activity (and suggesting that it does not possess a strong sedative potential) (Ref).

Drug-induced movement disorders

Buspirone has been associated with rare cases of drug-induced movement disorders, including dyskinesia, akathisia, dystonia (usually focal), myoclonus, and parkinsonism (Ref). In the majority of the parkinsonism cases, patients had a previous diagnosis of Parkinson disease. Of the buspirone-associated movement disorders reported, dyskinesia and akathisia appear to be the most commonly reported (Ref).

Mechanism: Although buspirone's mechanism of action is complex and not fully elucidated, it is believed to display high affinity for serotonin type 1A (5-HT1A) receptors where it acts as a partial agonist. It is also thought to have weak affinity for serotonin 5-HT2 receptors. In addition, it affects the dopaminergic pathway, where it is thought to act as a moderate antagonist at central dopamine D2 autoreceptors, resulting in increased firing rates and increasing dopamine levels in the synapse. It has also been suggested to display a "post synaptic dopamine antagonist-like effect," decreasing stimulation of the postsynaptic dopamine receptors. Its effects on dopamine may be dose dependent. Lastly, buspirone is believed to produce dose-dependent stimulation of the noradrenergic neurons of the locus ceruleus. In the various buspirone-associated movement disorders reported, buspirone-induced akathisia has been hypothesized to be attributed to buspirone's effect on noradrenergic neurotransmission; myoclonus and dystonia to its serotonin effects; and dyskinesia and parkinsonism to its dopaminergic-serotoninergic effects (Ref).

Onset: Varied; in a literature review, the mean onset to a buspirone-associated movement disorder was 4.6 weeks and the median onset was 4 weeks (range: 1 day to 21 weeks). In the majority of cases (76%), onset was within 1 month. The time to complete recovery following buspirone withdrawal was within 1 month in the majority of cases (88%). Most cases resolved following discontinuation, but in a couple of cases the symptoms continued after buspirone withdrawal (Ref).

Risk factors:

• Parkinsonism: Higher doses (ie, twice the average dose) (Ref).

Serotonin syndrome

Serotonin syndrome has been associated with buspirone when co-administered with another or multiple serotonergic agents, such as selective serotonin receptor inhibitors (SSRIs), particularly fluoxetine (Ref). There is also a case report of serotonin syndrome occurring with buspirone and linezolid, a reversible and nonselective monoamine oxidase inhibitor (MAOI); these agents should not be used concomitantly (Ref). Because buspirone is a partial serotonin agonist, some authors have questioned its potential to cause serotonin syndrome (Ref); however, reports of serotonin syndrome have been documented with buspirone at therapeutic doses when combined with other serotonergic agents. The diagnosis of serotonin syndrome is made based on the Hunter Serotonin Toxicity Criteria (Ref) and may result in a spectrum of symptoms, such as anxiety, agitation, confusion, delirium, hyperreflexia, muscle rigidity, myoclonus, tachycardia, tachypnea, and tremor. Severe cases may cause hyperthermia, significant autonomic instability (ie, rapid and severe changes in blood pressure and pulse), coma, and seizures (Ref).

Mechanism: Dose-related; serotonin syndrome can arise with any agent that directly or indirectly increases central serotonin neurotransmission at postsynaptic 5-HT1A and 5-HT2A receptors (Ref). Buspirone has been shown to have high affinity for serotonin 5-HT1A receptors, where it acts as a partial agonist, and has weak affinity for serotonin 5-HT2 receptors, and has variable effects on post- and presynaptic serotonin receptors (Ref).

Onset: Rapid (usually); in general, most cases of serotonin syndrome with a serotonergic agent occur within 24 hours of treatment initiation, overdose, or change in dose. In some patients, mild symptoms may be present for weeks before progressing to a more severe form of the syndrome (Ref).

Risk factors:

• Concomitant use of drugs that increase serotonin synthesis, block serotonin reuptake and/or impair serotonin metabolism (eg, MAOIs). Of note, concomitant use of some serotonergic agents, such as MAOIs, are contraindicated.

Adverse Reactions

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

>10%: Nervous system: Dizziness (3% to 12%) (table 1)

Buspirone: Adverse Reaction: Dizziness

Drug (Buspirone)

Placebo

Number of Patients (Buspirone)

Number of Patients (Placebo)

Comments

12%

3%

477

464

N/A

3%

0%

477

464

Lightheadedness

1% to 10%:

Cardiovascular: Chest pain (≥1%)

Dermatologic: Cold and clammy skin (≤1%), diaphoresis (≤1%), skin rash (1%)

Gastrointestinal: Diarrhea (2%), nausea (8%), sore throat (≥1%)

Nervous system: Abnormal dreams (≥1%), ataxia (1%), confusion (2%), drowsiness (10%) (table 2), excitement (2%) (table 3), headache (6%) (table 4), hostility (≤2%), insomnia (3% to 4% [Newton 1986a]) (table 5), nervousness (5%) (table 6), numbness (2%), outbursts of anger (≤2%), paresthesia (1%)

Buspirone: Adverse Reaction: Drowsiness

Drug (Buspirone)

Placebo

Number of Patients (Buspirone)

Number of Patients (Placebo)

10%

9%

477

464

Buspirone: Adverse Reaction: Excitement

Drug (Buspirone)

Placebo

Number of Patients (Buspirone)

Number of Patients (Placebo)

2%

0%

477

464

Buspirone: Adverse Reaction: Headache

Drug (Buspirone)

Placebo

Number of Patients (Buspirone)

Number of Patients (Placebo)

6%

3%

477

464

Buspirone: Adverse Reaction: Insomnia

Drug (Buspirone)

Placebo

Number of Patients (Buspirone)

Number of Patients (Placebo)

Source

4%

2%

984

334

Newton 1986a

3%

3%

477

464

Product labeling

Buspirone: Adverse Reaction: Nervousness

Drug (Buspirone)

Placebo

Number of Patients (Buspirone)

Number of Patients (Placebo)

5%

1%

477

464

Neuromuscular & skeletal: Asthenia (2%), musculoskeletal pain (≤1%), myalgia (≤1%), tremor (1%)

Ophthalmic: Blurred vision (2%)

Otic: Tinnitus (≥1%)

Respiratory: Nasal congestion (≥1%)

<1%:

Cardiovascular: Acute myocardial infarction, bradycardia, cardiac failure, cardiomyopathy, cerebrovascular accident, edema, facial edema, flushing, hypertension, hypotension, syncope

Dermatologic: Acne vulgaris, alopecia, pruritus, skin blister, thinning of nails, xeroderma

Endocrine & metabolic: Amenorrhea, change in libido, galactorrhea not associated with childbirth, menstrual disease, thyroid disease, weight gain, weight loss

Gastrointestinal: Anorexia, dysgeusia, flatulence, hiccups, increased appetite, irritable bowel syndrome, salivation

Genitourinary: Dysuria, impotence, nocturia, pelvic inflammatory disease, spotting, urinary frequency, urinary hesitancy, urinary incontinence

Hematologic & oncologic: Bleeding tendency disorder, bruise, eosinophilia, leukopenia, rectal hemorrhage, thrombocytopenia

Hepatic: Increased serum alanine aminotransferase, increased serum aspartate aminotransferase, increased serum transaminases

Nervous system: Akathisia, alcohol abuse, altered sense of smell, apathy, claustrophobia, cold intolerance, delayed ejaculation, depersonalization, dissociative reaction, dysphoria, euphoria, fear, glossopyrosis, hallucination, hyperacusis, involuntary muscle movements, malaise, psychosis (including exacerbation of psychosis [adult; Pantelis 1993]), roaring sensation in head, seizure, slowed reaction time, slurred speech, stupor, suicidal ideation, vertigo

Neuromuscular & skeletal: Arthralgia, muscle cramps, muscle rigidity, muscle spasm, stiffness

Ophthalmic: Conjunctivitis, eye pain, eye pruritus, eye redness, increased intraocular pressure, photophobia

Otic: Inner ear disturbance

Respiratory: Chest congestion, dyspnea, epistaxis, hyperventilation, laryngitis

Miscellaneous: Fever

Postmarketing:

Dermatologic: Ecchymoses, urticaria

Genitourinary: Urinary retention

Hypersensitivity: Angioedema, hypersensitivity reaction

Nervous system: Cogwheel rigidity, dystonia (Boylan 1990), emotional lability, extrapyramidal reaction, hypomania (Liegghio 1988a), mania (McIvor 1991), memory impairment, neurological deterioration (psychotic deterioration [children; Soni 1992]), parkinsonism (Clay 2003), restless leg syndrome, restlessness (Liegghio 1988b), serotonin syndrome (Baetz 1995)

Neuromuscular & skeletal: Dyskinesia (LeWitt 1993), myoclonus (Ritchie 1988)

Ophthalmic: Visual disturbance (including tunnel vision)

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.

Warnings/Precautions

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.

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.

Warnings: Additional Pediatric Considerations

Buspirone does not possess antipsychotic activity and should not be used in place of appropriate antipsychotic treatment; two pediatric cases of possible psychotic deterioration have been reported (Soni 1992).

Metabolism/Transport Effects

Substrate of CYP2D6 (minor), CYP3A4 (major); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential

Drug Interactions

Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the Lexicomp drug interactions program by clicking on the “Launch drug interactions program” link above.

Alcohol (Ethyl): BusPIRone may enhance the sedative effect of Alcohol (Ethyl). Risk C: Monitor therapy

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

CYP3A4 Inducers (Moderate): May decrease the serum concentration of BusPIRone. Risk C: 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. Risk D: Consider therapy modification

CYP3A4 Inhibitors (Moderate): May increase the serum concentration of BusPIRone. Risk C: 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. Dose adjustments of buspirone or a strong CYP3A4 inhibitor should be based on clinical assessment. Risk D: Consider therapy modification

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. Dose adjustments of buspirone or erythromycin should be based on clinical assessments. Risk D: Consider therapy modification

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

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

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

Grapefruit Juice: May increase the serum concentration of BusPIRone. Management: Patients should avoid consuming large quantities of grapefruit juice during use of buspirone. If patients consume grapefruit juice during buspirone therapy, monitor for increased buspirone adverse effects. Risk D: Consider therapy modification

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

Linezolid: BusPIRone may enhance the serotonergic effect of Linezolid. This could result in serotonin syndrome. Risk X: 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. Risk C: Monitor therapy

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

Monoamine Oxidase Inhibitors (Antidepressant): BusPIRone may enhance the serotonergic effect of Monoamine Oxidase Inhibitors (Antidepressant). This could result in serotonin syndrome. Risk X: 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. Risk C: 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. Risk D: Consider therapy modification

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. Risk C: Monitor therapy

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

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

Food Interactions

Food may decrease the absorption of buspirone, but it may also decrease the first-pass metabolism, thereby increasing the bioavailability of buspirone. Grapefruit juice may cause increased buspirone concentrations. Management: Administer with or without food, but must be consistent. Avoid intake of large quantities of grapefruit juice.

Pregnancy Considerations

Adverse events have not been observed in animal reproduction studies.

Limited outcome data following maternal use of buspirone are available from the National Pregnancy Registry for Psychiatric Medications, a prospective study of patients taking psychiatric medications during the first trimester of pregnancy (68 women, 72 infants) (Freeman 2022), and postmarketing data collected following the initial release of buspirone (16 first trimester exposures) (Wilton 1998).

Untreated anxiety in pregnant patients is associated with adverse maternal, fetal, and neonatal outcomes. Treatment of anxiety disorders during pregnancy should include the patient as part of a shared decision-making process. Due to lack of data, agents other than buspirone are preferred for use during pregnancy. Consider discontinuing buspirone and using alternative therapies during pregnancy unless there is a clear benefit to continuing treatment (Thorsness 2018)

Breastfeeding Considerations

It is not known if buspirone is present in breast milk.

In 1 case report, buspirone was not detected in the breast milk of a patient taking 15 mg three times daily during pregnancy and postpartum (samples obtained 13 days after delivery; limit of detection not noted) (Brent 1998). Adverse events were not observed in a fully breastfed infant 11 weeks of age following maternal use of buspirone 10 mg/day and venlafaxine (Newport 2009).

Breastfeeding is not recommended by the manufacturer.

Dietary Considerations

Avoid large quantities of grapefruit juice.

Monitoring Parameters

Mental status and alertness, symptoms of anxiety, signs of movement disorders (eg, dystonia, akathisia, pseudo-parkinsonism, tardive dyskinesia), signs/symptoms of serotonin syndrome such as mental status changes (eg, agitation, hallucinations, delirium, coma), autonomic instability (eg, tachycardia, labile BP, diaphoresis, flushing, hyperthermia), neuromuscular changes (eg, tremor, rigidity, myoclonus), GI symptoms (eg, nausea, vomiting, diarrhea), and/or seizures.

Mechanism of Action

The mechanism of action of buspirone is unknown. Buspirone has a high affinity for serotonin 5-HT1A and 5-HT2 receptors, without affecting benzodiazepine-GABA receptors. Buspirone has moderate affinity for dopamine D2 receptors.

Pharmacokinetics

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

Distribution: Vd: 5.3 L/kg (Gammans 1986)

Protein binding: ~86%

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

Bioavailability: Increased with food

Half-life elimination: 2 to 3 hours; increased with renal or hepatic impairment

Time to peak, serum: 40 to 90 minutes

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

Pharmacokinetics: Additional Considerations

Altered kidney function: AUC increased 4-fold.

Hepatic function impairment: AUC increased 13-fold.

Pricing: US

Tablets (busPIRone HCl Oral)

5 mg (per each): $0.15 - $0.77

7.5 mg (per each): $1.09 - $1.58

10 mg (per each): $0.21 - $1.35

15 mg (per each): $0.65 - $2.12

30 mg (per each): $3.63 - $3.64

Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.

Brand Names: International
  • Actium (PY);
  • Ankisilon (FI);
  • Anksilon (SE);
  • Ansial (AR);
  • Ansitec (BR);
  • Ansiten (PT);
  • Anxiolan (TH);
  • Anxiron (AE, CY, HN, HU, IQ, IR, JO, LB, LY, OM, SA, SY, YE);
  • Anxut (DE);
  • Bespar (GR);
  • Buscalm (IN);
  • Busiral (AE, CY, IQ, IR, JO, LB, LY, OM, SA, SY, YE);
  • Buson (IN);
  • Busone (KR);
  • Busp (TW);
  • Buspalex (EG);
  • Buspar (AT, CH, CZ, DK, EC, EE, EG, FR, GB, HK, IE, IT, KR, LU, MT, MX, NL, PK, RU, SA, SK, TR);
  • Busparium (UY);
  • Busper (BD);
  • Buspin (IN);
  • Buspon (TR);
  • Busron (KR, LK);
  • Dalpas (VE);
  • Dergelasen (CO);
  • Duvaline (PY);
  • Exupar (EG);
  • Itigil (PT);
  • Kallmiren (AE, CY, IQ, IR, JO, LB, LY, OM, SA, SY, YE);
  • Loxapin (MT);
  • Normaton (DO, GT, PA, SV);
  • Pasrin (ZA);
  • Paxon (CL);
  • Qibite (CN);
  • Relac (TW);
  • Relax (EC);
  • Sepirone (TW);
  • Seropar (EG);
  • Sorbon (IL);
  • Spamilan (PL);
  • Spitomin (BG, HU, LT, LV, RO, SK, UA);
  • Suxin (CN);
  • Travin (HR);
  • Xiety (ID)


For country code abbreviations (show table)
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  3. Baetz M, Malcolm D. Serotonin syndrome from fluvoxamine and buspirone. Can J Psychiatry. 1995;40(7):428-429. doi:10.1177/070674379504000721 [PubMed 8548727]
  4. Barbhaiya RH, Shukla UA, Pfeffer M, et al. Disposition kinetics of buspirone in patients with renal or hepatic impairment after administration of single and multiple doses. Eur J Clin Pharmacol. 1994;46(1):41-47. doi:10.1007/BF00195914 [PubMed 7911763]
  5. Bartlett D. Drug-induced serotonin syndrome. Crit Care Nurse. 2017;37(1):49-54. doi:10.4037/ccn2017169 [PubMed 28148614]
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