Buspar (Buspirone): Side Effects, Uses, Dosage, Interactions, Warnings (2024)

Drug Summary

What Is Buspar?

Buspar (buspirone) is an antianxiety agent prescribed for the treatment of anxiety. Buspar is available as a generic drug.

What Are Side Effects of Buspar?

Common side effects of Buspar include:

  • dizziness,
  • nausea,
  • headache,
  • nervousness,
  • lightheadedness,
  • drowsiness,
  • feeling tired,
  • blurred vision,
  • restlessness,
  • dry mouth,
  • upset stomach,
  • stuffy nose,
  • sore throat,
  • ringing in the ears,
  • excitement, and
  • sleep problems (insomnia or strange dreams).

Dosage for Buspar

Buspar usual adult starting dose is 10-30mg daily in 2-3 divided doses up to a maximum of 60mg a day.

What Drugs, Substances, or Supplements Interact with Buspar?

Common drug interactions of Buspar include monoamine oxidase (MAO) inhibitors (for example, isocarboxazid [Marplan]), trazodone (Desyrel), warfarin (Coumadin), erythromycin, itraconazole (Sporanox), nefazodone (Serzone) and rifampin.

Buspar During Pregnancy and Breastfeeding

There are no adequate studies of Buspar in pregnant women and it is not known if Buspar is secreted in human breast milk. Use during pregnancy is not recommended unless the potential benefit outweighs the potential unknown risk to the fetus. It is unknown if Buspar passes into breast milk or if it could harm a nursing baby. Consult your doctor before breastfeeding.

Additional Information

Our Buspar Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

Description for Buspar

Buspirone hydrochloride tablets, USP are an antianxiety agent that is not chemically or pharmacologically related to the benzodiazepines, barbiturates, or other sedative/anxiolytic drugs.

Buspirone hydrochloride, USP is a white crystalline powder. It is very soluble in water; freely soluble in methanol and in methylene chloride; sparingly soluble in ethanol and in acetonitrile; very slightly soluble in ethyl acetate and practically insoluble in hexanes. Its molecular weight is 422. Chemically, buspirone hydrochloride is 8-[4-[4-(2-pyrimidinyl)-1-piperazinyl]butyl]-8-azaspiro[4.5]decane-7,9- dione monohydrochloride. The molecular formula C21H31N5O2•HCl is represented by the following structural formula:

Buspar (Buspirone): Side Effects, Uses, Dosage, Interactions, Warnings (1)

Each buspirone hydrochloride tablet intended for oral administration contains 5 mg or 10 mg or 15 mg or 30 mg buspirone hydrochloride (equivalent to 4.6 mg, 9.1 mg, 13.7 mg, and 27.4 mg of buspirone free base, respectively). In addition, each tablet contains the following inactive ingredients: colloidal silicon dioxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose and sodium starch glycolate. The 5 mg and 10 mg tablets are scored so they can be bisected. Thus, the 5 mg tablet can also provide 2.5 mg dose, and the 10 mg tablet can provide a 5 mg dose. The 15 mg and 30 mg tablets are scored so they can be either bisected or trisected. Thus, a single 15 mg tablet can provide the following doses: 15 mg (entire tablet), 10 mg (two thirds of a tablet), 7.5 mg (one half of a tablet), or 5 mg (one third of a tablet). A single 30 mg tablet can provide the following doses: 30 mg (entire tablet), 20 mg (two thirds of a tablet), 15 mg (one half of a tablet), or 10 mg (one third of a tablet).

Uses for Buspar

Buspirone hydrochloride tablets are indicated for the management of anxiety disorders or the short-termrelief of the symptoms of anxiety. Anxiety or tension associated with the stress of everyday life usuallydoes not require treatment with an anxiolytic.

The efficacy of buspirone hydrochloride tablets have been demonstrated in controlled clinical trials ofoutpatients whose diagnosis roughly corresponds to Generalized Anxiety Disorder (GAD). Many of thepatients enrolled in these studies also had coexisting depressive symptoms and buspirone hydrochloridetablets relieved anxiety in the presence of these coexisting depressive symptoms. The patientsevaluated in these studies had experienced symptoms for periods of 1 month to over 1 year prior to thestudy, with an average symptom duration of 6 months. Generalized Anxiety Disorder (300.02) isdescribed in the American Psychiatric Association’s Diagnostic and Statistical Manual, III1 as follows:

Generalized, persistent anxiety (of at least 1 month continual duration), manifested by symptoms fromthree of the four following categories:

Motor Tension

Shakiness, jitteriness, jumpiness, trembling, tension, muscle aches, fatigability, inability to relax, eyelid twitch, furrowed brow, strained face, fidgeting, restlessness, easy startle.

Autonomic Hyperactivity

Sweating, heart pounding or racing, cold, clammy hands, dry mouth, dizziness, lightheadedness,paresthesias (tingling in hands or feet), upset stomach, hot or cold spells, frequent urination, diarrhea,discomfort in the pit of the stomach, lump in the throat, flushing, pallor, high resting pulse andrespiration rate.

Apprehensive Expectation

Anxiety, worry, fear, rumination, and anticipation of misfortune to self or others.

Vigilance and Scanning

Hyperattentiveness resulting in distractibility, difficulty in concentrating, insomnia, feeling "on edge,"irritability, impatience.

The above symptoms would not be due to another mental disorder, such as a depressive disorder orschizophrenia. However, mild depressive symptoms are common in GAD.

The effectiveness of buspirone hydrochloride tablets in long-term use, that is, for more than 3 to 4weeks, has not been demonstrated in controlled trials. There is no body of evidence available thatsystematically addresses the appropriate duration of treatment for GAD. However, in a study of longtermuse, 264 patients were treated with buspirone hydrochloride tablets for 1 year without ill effect.Therefore, the physician who elects to use buspirone hydrochloride tablets for extended periodsshould periodically reassess the usefulness of the drug for the individual patient.

Dosage for Buspar

The recommended initial dose is 15 mg daily (7.5 mg b.i.d.). To achieve an optimal therapeuticresponse, at intervals of 2 to 3 days the dosage may be increased 5 mg per day, as needed. The maximumdaily dosage should not exceed 60 mg per day. In clinical trials allowing dose titration, divided dosesof 20 mg to 30 mg per day were commonly employed.

The bioavailability of buspirone is increased when given with food as compared to the fasted state (see CLINICAL PHARMACOLOGY). Consequently, patients should take buspirone in a consistent mannerwith regard to the timing of dosing; either always with or always without food.

When buspirone is to be given with a potent inhibitor of CYP3A4, the dosage recommendationsdescribed in the DRUG INTERACTIONS section should be followed.

HOW SUPPLIED

Buspirone Hydrochloride Tablets USP, 5 mg are white to off-white, capsule-shaped, flat- faced,beveled-edge tablets debossed with bisect on one side; one side of bisect is debossed with 'ZE' andanother is debossed with '36' and other side is plain

Manufacturer details: N/A. Revised: May 2016

Side Effects for Buspar

No information provided.

Drug Interactions for Buspar

Psychotropic Agents

MAO Inhibitors

It is recommended that buspirone hydrochloride tablets not be used concomitantly with MAO inhibitors (see WARNINGS).

Amitriptyline

After addition of buspirone to the amitriptyline dose regimen, no statistically significant differences in the steady-state pharmaco*kinetic parameters (Cmax, AUC, and Cmin) of amitriptyline or its metabolite nortriptyline were observed.

Diazepam

After addition of buspirone to the diazepam dose regimen, no statistically significant differences in the steady-state pharmaco*kinetic parameters (Cmax, AUC, and Cmin) were observed for diazepam, but increases of about 15% were seen for nordiazepam, and minor adverse clinical effects (dizziness, headache, and nausea) were observed.

Haloperidol

In a study in normal volunteers, concomitant administration of buspirone and haloperidol resulted in increased serum haloperidol concentrations. The clinical significance of this finding is not clear.

Nefazodone

[see Inhibitors and Inducers of Cytochrome P450 3A4 (CYP3A4)].

Trazodone

There is one report suggesting that the concomitant use of Desyrel®# (trazodone hydrochloride) and buspirone may have caused 3- to 6-fold elevations on SGPT (ALT) in a few patients. In a similar study attempting to replicate this finding, no interactive effect on hepatic transaminases was identified.

Triazolam/Flurazepam

Coadministration of buspirone with either triazolam or flurazepam did not appear to prolong or intensify the sedative effects of either benzodiazepine.

Other Psychotropics

Because the effects of concomitant administration of buspirone with most other psychotropic drugs have not been studied, the concomitant use of buspirone with other CNS-active drugs should be approached with caution.

Inhibitors And Inducers Of Cytochrome P450 3A4 (CYP3A4)

Buspirone has been shown in vitro to be metabolized by CYP3A4. This finding is consistent with the in vivo interactions observed between buspirone and the following:

Diltiazem And Verapamil

In a study of nine healthy volunteers, coadministration of buspirone (10 mg as a single dose) with verapamil (80 mg t.i.d.) or diltiazem (60 mg t.i.d.) increased plasma buspirone concentrations (verapamil increased AUC and Cmax of buspirone 3.4-fold while diltiazem increased AUC and Cmax 5.5-fold and 4-fold, respectively.) Adverse events attributable to buspirone may be more likely during concomitant administration with either diltiazem or verapamil. Subsequent dose adjustment may be necessary and should be based on clinical assessment.

Erythromycin

In a study in healthy volunteers, coadministration of buspirone (10 mg as a single dose) with erythromycin (1.5 g/day for 4 days) increased plasma buspirone concentrations (5-fold increase in Cmax and 6-fold increase in AUC). These pharmaco*kinetic interactions were accompanied by an increased incidence of side effects attributable to buspirone. If the two drugs are to be used in combination, a low dose of buspirone (e.g., 2.5 mg b.i.d.) is recommended. Subsequent dose adjustment of either drug should be based on clinical assessment.

Grapefruit Juice

In a study in healthy volunteers, coadministration of buspirone (10 mg as a single dose) with grapefruit juice (200 mL double-strength t.i.d. for 2 days) increased plasma buspirone concentrations (4.3-fold increase in Cmax; 9.2-fold increase in AUC). Patients receiving buspirone should be advised to avoid drinking such large amounts of grapefruit juice.

Itraconazole

In a study in healthy volunteers, coadministration of buspirone (10 mg as a single dose) with itraconazole (200 mg/day for 4 days) increased plasma buspirone concentrations (13-fold increase in Cmax and 19-fold increase in AUC). These pharmaco*kinetic interactions were accompanied by an increased incidence of side effects attributable to buspirone. If the two drugs are to be used in combination, a low dose of buspirone (e.g., 2.5 mg q.d.) is recommended. Subsequent dose adjustment of either drug should be based on clinical assessment.

Nefazodone

In a study of steady-state pharmaco*kinetics in healthy volunteers, coadministration of buspirone (2.5 or 5 mg b.i.d.) with nefazodone (250 mg b.i.d.) resulted in marked increases in plasma buspirone concentrations (increases up to 20-fold in Cmax and up to 50-fold in AUC) and statistically significant decreases (about 50%) in plasma concentrations of the buspirone metabolite 1-PP. With 5 mg b.i.d. doses of buspirone, slight increases in AUC were observed for nefazodone (23%) and its metabolites hydroxynefazodone (HO-NEF) (17%) and meta-chlorophenylpiperazine (9%). Slight increases in Cmax were observed for nefazodone (8%) and its metabolite HO-NEF (11%).

Subjects receiving buspirone 5 mg b.i.d. and nefazodone 250 mg b.i.d experienced lightheadedness, asthenia, dizziness, and somnolence, adverse events also observed with either drug alone. If the two drugs are to be used in combination, a low dose of buspirone (e.g., 2.5 mg q.d.) is recommended. Subsequent dose adjustment of either drug should be based on clinical assessment.

Rifampin

In a study in healthy volunteers, coadministration of buspirone (30 mg as a single dose) with rifampin (600 mg/day for 5 days) decreased the plasma concentrations (83.7% decrease in Cmax; 89.6% decrease in AUC) and pharmacodynamic effects of buspirone. If the two drugs are to be used in combination, the dosage of buspirone may need adjusting to maintain anxiolytic effect.

Other Inhibitors And Inducers Of CYP3A4

Substances that inhibit CYP3A4, such as ketoconazole or ritonavir, may inhibit buspirone metabolism and increase plasma concentrations of buspirone while substances that induce CYP3A4, such as dexamethasone, or certain anticonvulsants (phenytoin, phenobarbital, carbamazepine), may increase the rate of buspirone metabolism. If a patient has been titrated to a stable dosage on buspirone, a dose adjustment of buspirone may be necessary to avoid adverse events attributable to buspirone or diminished anxiolytic activity. Consequently, when administered with a potent inhibitor of CYP3A4, a low dose of buspirone used cautiously is recommended. When used in combination with a potent inducer of CYP3A4 the dosage of buspirone may need adjusting to maintain anxiolytic effect.

Other Drugs

Cimetidine

Coadministration of buspirone with cimetidine was found to increase Cmax (40%) and Tmax (2–fold), but had minimal effects on the AUC of buspirone.

Protein Binding

In vitro, buspirone does not displace tightly bound drugs like phenytoin, propranolol, and warfarin from serum proteins. However, there has been one report of prolonged prothrombin time when buspirone was added to the regimen of a patient treated with warfarin. The patient was also chronically receiving phenytoin, phenobarbital, digoxin, and Synthroid®*. In vitro, buspirone may displace less firmly bound drugs like digoxin. The clinical significance of this property is unknown.

Therapeutic levels of aspirin, desipramine, diazepam, flurazepam, ibuprofen, propranolol, thioridazine, and tolbutamide had only a limited effect on the extent of binding of buspirone to plasma proteins (see CLINICAL PHARMACOLOGY).

Drug/Laboratory Test Interactions

Buspirone hydrochloride may interfere with the urinary metanephrine/catecholamine assay. It has been mistakenly read as metanephrine during routine assay testing for pheochromocytoma, resulting in a false positive laboratory result. Buspirone hydrochloride should therefore be discontinued for at least 48 hours prior to undergoing a urine collection for catecholamines.

Drug Abuse and Dependence

Controlled Substance Class

Buspirone hydrochloride is not a controlled substance.

Physical And Psychological Dependence

In human and animal studies, buspirone has shown no potential for abuse or diversion and there is no evidence that it causes tolerance, or either physical or psychological dependence. Human volunteers with a history of recreational drug or alcohol usage were studied in two doubleblind clinical investigations. None of the subjects were able to distinguish between buspirone hydrochloride tablets and placebo. By contrast, subjects showed a statistically significant preference for methaqualone and diazepam. Studies in monkeys, mice, and rats have indicated that buspirone lacks potential for abuse. Following chronic administration in the rat, abrupt withdrawal of buspirone did not result in the loss of body weight commonly observed with substances that cause physical dependency.

Although there is no direct evidence that buspirone hydrochloride tablets causes physical dependence or drug-seeking behavior, it is difficult to predict from experiments the extent to which a CNS-active drug will be misused, diverted, and/or abused once marketed. Consequently, physicians should carefully evaluate patients for a history of drug abuse and follow such patients closely, observing them for signs of buspirone hydrochloride tablets misuse or abuse (e.g., development of tolerance, incrementation of dose, drug-seeking behavior).

Controlled Substance Class

Buspirone hydrochloride is not a controlled substance.

Physical And Psychological Dependence

In human and animal studies, buspirone has shown no potential for abuse or diversion and there is no evidence that it causes tolerance, or either physical or psychological dependence. Human volunteers with a history of recreational drug or alcohol usage were studied in two doubleblind clinical investigations. None of the subjects were able to distinguish between buspirone hydrochloride tablets and placebo. By contrast, subjects showed a statistically significant preference for methaqualone and diazepam. Studies in monkeys, mice, and rats have indicated that buspirone lacks potential for abuse. Following chronic administration in the rat, abrupt withdrawal of buspirone did not result in the loss of body weight commonly observed with substances that cause physical dependency.

Although there is no direct evidence that buspirone hydrochloride tablets causes physical dependence or drug-seeking behavior, it is difficult to predict from experiments the extent to which a CNS-active drug will be misused, diverted, and/or abused once marketed. Consequently, physicians should carefully evaluate patients for a history of drug abuse and follow such patients closely, observing them for signs of buspirone hydrochloride tablets misuse or abuse (e.g., development of tolerance, incrementation of dose, drug-seeking behavior).

Warnings for Buspar

The administration of buspirone hydrochloride tablets to a patient taking a monoamine oxidase inhibitor(MAOI) may pose a hazard. There have been reports of the occurrence of elevated blood pressurewhen buspirone hydrochloride tablets have been added to a regimen including an MAOI. Therefore, itis recommended that buspirone hydrochloride tablets not be used concomitantly with an MAOI.

Because buspirone hydrochloride tablets have no established antipsychotic activity, it should not beemployed in lieu of appropriate antipsychotic treatment.

Precautions for Buspar

General

Interference With Cognitive And Motor Performance

Studies indicate that buspirone hydrochloride tablets are less sedating than other anxiolytics and that itdoes not produce significant functional impairment. However, its CNS effects in any individual patientmay not be predictable. Therefore, patients should be cautioned about operating an automobile or usingcomplex machinery until they are reasonably certain that buspirone treatment does not affect themadversely.

While formal studies of the interaction of buspirone hydrochloride with alcohol indicate that buspironedoes not increase alcohol-induced impairment in motor and mental performance, it is prudent to avoidconcomitant use of alcohol and buspirone.

Potential For Withdrawal Reactions In Sedative/Hypnotic/Anxiolytic Drug-Dependent Patients

Because buspirone hydrochloride tablets do not exhibit cross-tolerance with benzodiazepines and othercommon sedative/hypnotic drugs, it will not block the withdrawal syndrome often seen with cessation oftherapy with these drugs. Therefore, before starting therapy with buspirone hydrochloride tablets, it isadvisable to withdraw patients gradually, especially patients who have been using a CNS-depressantdrug chronically, from their prior treatment. Rebound or withdrawal symptoms may occur over varyingtime periods, depending in part on the type of drug, and its effective half-life of elimination.

The syndrome of withdrawal from sedative/hypnotic/anxiolytic drugs can appear as any combination ofirritability, anxiety, agitation, insomnia, tremor, abdominal cramps, muscle cramps, vomiting, sweating,flu-like symptoms without fever, and occasionally, even as seizures.

Possible Concerns Related To Buspirone’s Binding To Dopamine Receptors

Because buspirone can bind to central dopamine receptors, a question has been raised about its potentialto cause acute and chronic changes in dopamine-mediated neurological function (e.g., dystonia, pseudoparkinsonism,akathisia, and tardive dyskinesia). Clinical experience in controlled trials has failed toidentify any significant neuroleptic-like activity; however, a syndrome of restlessness, appearingshortly after initiation of treatment, has been reported in some small fraction of buspirone-treatedpatients. The syndrome may be explained in several ways. For example, buspirone may increase centralnoradrenergic activity; alternatively, the effect may be attributable to dopaminergic effects (i.e.,represent akathisia). See ADVERSE REACTIONS: Postmarketing Experience.

Information For Patients

To assure safe and effective use of buspirone hydrochloride tablets, the following information andinstructions should be given to patients:

Inform your physician about any medications, prescription or non-prescription, alcohol, or drugs thatyou are now taking or plan to take during your treatment with buspirone hydrochloride tablets.

Inform your physician if you are pregnant, or if you are planning to become pregnant, or if you becomepregnant while you are taking buspirone hydrochloride tablets.

Inform your physician if you are breastfeeding an infant.

Until you experience how this medication affects you, do not drive a car or operate potentiallydangerous machinery.

You should take buspirone hydrochloride consistently, either always with or always without food.

During your treatment with buspirone hydrochloride tablets, avoid drinking large amounts of grapefruitjuice.

Laboratory Tests

There are no specific laboratory tests recommended.

Carcinogenesis, Mutagenesis, Impairment Of Fertility

No evidence of carcinogenic potential was observed in rats during a 24 month study at approximately133 times the maximum recommended human oral dose; or in mice, during an 18 month study atapproximately 167 times the maximum recommended human oral dose.

With or without metabolic activation, buspirone did not induce point mutations in five strains ofSalmonella typhimurium (Ames Test) or mouse lymphoma L5178YTK+ cell cultures, nor was DNAdamage observed with buspirone in Wi-38 human cells. Chromosomal aberrations or abnormalities didnot occur in bone marrow cells of mice given one or five daily doses of buspirone.

Pregnancy

Teratogenic Effects

Pregnancy Category B

No fertility impairment or fetal damage was observed in reproduction studies performed in rats andrabbits at buspirone doses of approximately 30 times the maximum recommended human dose. Inhumans, however, adequate and well-controlled studies during pregnancy have not been performed.Because animal reproduction studies are not always predictive of human response, this drug should beused during pregnancy only if clearly needed.

Labor And Delivery

The effect of buspirone hydrochloride on labor and delivery in women is unknown. No adverse effectswere noted in reproduction studies in rats.

Nursing Mothers

The extent of the excretion in human milk of buspirone or its metabolites is not known. In rats, however,buspirone and its metabolites are excreted in milk. Buspirone hydrochloride tablets administration tonursing women should be avoided if clinically possible.

Pediatric Use

The safety and effectiveness of buspirone were evaluated in two placebo-controlled 6 week trialsinvolving a total of 559 pediatric patients (ranging from 6 to 17 years of age) with GAD. Doses studiedwere 7.5 mg to 30 mg b.i.d. (15 to 60 mg/day). There were no significant differences betweenbuspirone and placebo with regard to the symptoms of GAD following doses recommended for thetreatment of GAD in adults. Pharmaco*kinetic studies have shown that, for identical doses, plasmaexposure to buspirone and its active metabolite, 1-PP, are equal to or higher in pediatric patients thanadults. No unexpected safety findings were associated with buspirone in these trials. There are no longtermsafety or efficacy data in this population.

Geriatric Use

In one study of 6632 patients who received buspirone for the treatment of anxiety, 605 patients were ≥65 years old and 41 were ≥ 75 years old; the safety and efficacy profiles for these 605 elderly patients(mean age =70.8 years) were similar to those in the younger population (mean age = 43.3 years).Review of spontaneously reported adverse clinical events has not identified differences betweenelderly and younger patients, but greater sensitivity of some older patients cannot be ruled out.

There were no effects of age on the pharmaco*kinetics of buspirone (see CLINICAL PHARMACOLOGY, Special Populations).

Use In Patients With Impaired Hepatic Or Renal Function

Buspirone is metabolized by the liver and excreted by the kidneys. A pharmaco*kinetic study in patientswith impaired hepatic or renal function demonstrated increased plasma levels and a lengthened half-lifeof buspirone. Therefore, the administration of buspirone hydrochloride tablets to patients with severehepatic or renal impairment cannot be recommended (see CLINICAL PHARMACOLOGY).

Overdose Information for Buspar

No information provided.

Contraindications for Buspar

Buspirone hydrochloride tablets are contraindicated in patients hypersensitive to buspironehydrochloride.

Clinical Pharmacology for Buspar

The mechanism of action of buspirone is unknown. Buspirone differs from typical benzodiazepineanxiolytics in that it does not exert anticonvulsant or muscle relaxant effects. It also lacks the prominentsedative effect that is associated with more typical anxiolytics. In vitro preclinical studies have shownthat buspirone has a high affinity for serotonin (5-HT1A) receptors. Buspirone has no significantaffinity for benzodiazepine receptors and does not affect GABA binding in vitro or in vivo when testedin preclinical models.

Buspirone has moderate affinity for brain D2-dopamine receptors. Some studies do suggest thatbuspirone may have indirect effects on other neurotransmitter systems.

Buspirone hydrochloride is rapidly absorbed in man and undergoes extensive first-pass metabolism. In aradiolabeled study, unchanged buspirone in the plasma accounted for only about 1% of the radioactivityin the plasma. Following oral administration, plasma concentrations of unchanged buspirone are verylow and variable between subjects. Peak plasma levels of 1 ng/mL to 6 ng/mL have been observed 40 to90 minutes after single oral doses of 20 mg. The single-dose bioavailability of unchanged buspironewhen taken as a tablet is on the average about 90% of an equivalent dose of solution, but there is largevariability.

The effects of food upon the bioavailability of buspirone hydrochloride tablets have been studied ineight subjects. They were given a 20 mg dose with and without food; the area under the plasmaconcentration-time curve (AUC) and peak plasma concentration (Cmax) of unchanged buspironeincreased by 84% and 116%, respectively, but the total amount of buspirone immunoreactive materialdid not change. This suggests that food may decrease the extent of presystemic clearance of buspirone(see DOSAGE AND ADMINISTRATION).

A multiple-dose study conducted in 15 subjects suggests that buspirone has nonlinear pharmaco*kinetics.Thus, dose increases and repeated dosing may lead to somewhat higher blood levels of unchangedbuspirone than would be predicted from results of single-dose studies.

An in vitro protein binding study indicated that approximately 86% of buspirone is bound to plasmaproteins. It was also observed that aspirin increased the plasma levels of free buspirone by 23%, whileflurazepam decreased the plasma levels of free buspirone by 20%. However, it is not known whetherthese drugs cause similar effects on plasma levels of free buspirone in vivo, or whether such changes,if they do occur, cause clinically significant differences in treatment outcome. An in vitro studyindicated that buspirone did not displace highly protein-bound drugs such as phenytoin, warfarin, andpropranolol from plasma protein, and that buspirone may displace digoxin.

Buspirone is metabolized primarily by oxidation, which in vitro has been shown to be mediated bycytochrome P450 3A4 (CYP3A4) (see DRUG INTERACTIONS). Several hydroxylatedderivatives and a pharmacologically active metabolite, 1-pyrimidinylpiperazine (1-PP), are produced. Inanimal models predictive of anxiolytic potential, 1-PP has about one quarter of the activity of buspirone,but is present in up to 20-fold greater amounts. However, this is probably not important in humans: bloodsamples from humans chronically exposed to buspirone hydrochloride do not exhibit high levels of 1-PP; mean values are approximately 3 ng/mL and the highest human blood level recorded among 108chronically dosed patients was 17 ng/mL, less than 1/200th of 1-PP levels found in animals given largedoses of buspirone without signs of toxicity.

In a single-dose study using 14C-labeled buspirone, 29% to 63% of the dose was excreted in the urinewithin 24 hours, primarily as metabolites; fecal excretion accounted for 18% to 38% of the dose. Theaverage elimination half-life of unchanged buspirone after single doses of 10 mg to 40 mg is about 2 to3 hours.

Special Populations

Age And Gender Effects

After single or multiple doses in adults, no significant differences in buspirone pharmaco*kinetics (AUCand Cmax) were observed between elderly and younger subjects or between men and women.

Hepatic Impairment

After multiple-dose administration of buspirone to patients with hepatic impairment, steady-state AUCof buspirone increased 13-fold compared with healthy subjects (see PRECAUTIONS).

Renal Impairment

After multiple-dose administration of buspirone to renally impaired (Clcr = 10 to 70 mL/min/1.73 m2)patients, steady-state AUC of buspirone increased 4-fold compared with healthy (Clcr ≥ 80 mL/min/1.73m2) subjects (see PRECAUTIONS).

Race Effects

The effects of race on the pharmaco*kinetics of buspirone have not been studied.

Patient Information for Buspar

Buspirone Hydrochloride
Tablets, USP
For 15 mg and 30 mg tablets

HOW TO USE

Response to buspirone varies among individuals. Your physician may find it necessary toadjust your dosage to obtain the proper response.

Each tablet is scored and can be broken accurately.

To break a tablet accurately and easily, hold the tablet between your thumbs and index fingers close to the appropriate tablet score (groove). Then, with the tablet score facing you, apply pressure and snap the tablet segments apart (segments breaking incorrectly should not be used).

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Buspar (Buspirone): Side Effects, Uses, Dosage, Interactions, Warnings (3)

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Buspar (Buspirone): Side Effects, Uses, Dosage, Interactions, Warnings (2024)
Top Articles
FundYourFX - Instant Funding. Zero loss liability. Refundable Fee.
What Income And Wealth Put You In The Top 1%? | Bankrate
Why Are Fuel Leaks A Problem Aceable
123 Movies Black Adam
Satyaprem Ki Katha review: Kartik Aaryan, Kiara Advani shine in this pure love story on a sensitive subject
Lifewitceee
30 Insanely Useful Websites You Probably Don't Know About
10 Popular Hair Growth Products Made With Dermatologist-Approved Ingredients to Shop at Amazon
Craigslist Free Stuff Appleton Wisconsin
Pitt Authorized User
Ncaaf Reference
6th gen chevy camaro forumCamaro ZL1 Z28 SS LT Camaro forums, news, blog, reviews, wallpapers, pricing – Camaro5.com
Help with Choosing Parts
Hilo Hi Craigslist
My.tcctrack
WEB.DE Apps zum mailen auf dem SmartPhone, für Ihren Browser und Computer.
Unity - Manual: Scene view navigation
Wgu Academy Phone Number
Selfservice Bright Lending
Cvs El Salido
Grimes County Busted Newspaper
Timeforce Choctaw
6 Most Trusted Pheromone perfumes of 2024 for Winning Over Women
Best Middle Schools In Queens Ny
Keyn Car Shows
Danielle Ranslow Obituary
Royalfh Obituaries Home
Pronóstico del tiempo de 10 días para San Josecito, Provincia de San José, Costa Rica - The Weather Channel | weather.com
Marlene2995 Pagina Azul
Craigslist Comes Clean: No More 'Adult Services,' Ever
Login.castlebranch.com
Lesson 1.1 Practice B Geometry Answers
Angel del Villar Net Worth | Wife
Acuity Eye Group - La Quinta Photos
Scioto Post News
Best Restaurants In Blacksburg
7543460065
Tryst Houston Tx
Union Corners Obgyn
The Wait Odotus 2021 Watch Online Free
Owa Hilton Email
3 bis 4 Saison-Schlafsack - hier online kaufen bei Outwell
2017 Ford F550 Rear Axle Nut Torque Spec
The Complete Uber Eats Delivery Driver Guide:
Marcel Boom X
Nurses May Be Entitled to Overtime Despite Yearly Salary
Rick And Morty Soap2Day
The 13 best home gym equipment and machines of 2023
German American Bank Owenton Ky
Fresno Craglist
Urban Airship Acquires Accengage, Extending Its Worldwide Leadership With Unmatched Presence Across Europe
How To Find Reliable Health Information Online
Latest Posts
Article information

Author: Gregorio Kreiger

Last Updated:

Views: 6454

Rating: 4.7 / 5 (77 voted)

Reviews: 92% of readers found this page helpful

Author information

Name: Gregorio Kreiger

Birthday: 1994-12-18

Address: 89212 Tracey Ramp, Sunside, MT 08453-0951

Phone: +9014805370218

Job: Customer Designer

Hobby: Mountain biking, Orienteering, Hiking, Sewing, Backpacking, Mushroom hunting, Backpacking

Introduction: My name is Gregorio Kreiger, I am a tender, brainy, enthusiastic, combative, agreeable, gentle, gentle person who loves writing and wants to share my knowledge and understanding with you.