Buspirone Hydrochloride 5 mg Tablet, 500-count — NDC 42543-741-07 (Billing 42543-0741-07)

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

Serotonin Syndrome The development of a potentially life-threatening serotonin syndrome has been reported with SNRIs SSRIs, and other serotonergic drugs, including buspirone, alone but particularly with concomitant use of other serotonergic drugs (including triptans), with drugs that impair metabolism of serotonin (in particular, MAOIs, including reversible MAOIs such as linezolid and intravenous methylene blue), or with antipsychotics or other dopamine antagonists. Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular changes (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).

Patients should be monitored for emergence of serotonin syndrome. The concomitant use of buspirone with MAOIs intended to treat depression is contraindicated. Buspirone should also not be started in a patient who is being treated with reversible MAOIs such as linezolid or intravenous methylene blue.

All reports with methylene blue that provided information on the route of administration involved intravenous administration in the dose range of 1 mg/kg to 8 mg/kg. There have been no reports involving the administration of methylene blue by other routes (such as oral tablets or local tissue injection) or at lower doses. There may be circumstances when it is necessary to initiate treatment with a reversible MAOI such as linezolid or intravenous methylene blue in a patient taking buspirone.

Buspirone should be discontinued before initiating treatment with the reversible MAOI [see CONTRAINDICATIONS, DOSAGE AND ADMINISTRATION AND DRUG INTERACTIONS ]. If concomitant use of buspirone with a 5-hydroxytryptmine receptor agonist (triptan) is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases. The concomitant use of buspirone with serotonin precursors (such as tryptophan) is not recommended.

Treatment with buspirone and any concomitant serotonergic or antidopaminergic agents, including antipsychotics, should be discontinued immediately if the above events occur and supportive symptomatic treatment should be initiated. Because buspirone hydrochloride tablets have no established antipsychotic activity, it should not be employed in lieu of appropriate antipsychotic treatment.

ADVERSE REACTIONS (See also PRECAUTIONS) Commonly Observed The more commonly observed untoward events associated with the use of buspirone not seen at an equivalent incidence among placebo-treated patients include dizziness, nausea, headache, nervousness, lightheadedness, and excitement. Associated With Discontinuation of Treatment One guide to the relative clinical importance of adverse events associated with buspirone is provided by the frequency with which they caused drug discontinuation during clinical testing.

Approximately 10% of the 2200 anxious patients who participated in the buspirone premarketing clinical efficacy trials in anxiety disorders lasting 3 to 4 weeks discontinued treatment due to an adverse event. The more common events causing discontinuation included: central nervous system disturbances (3.4%), primarily dizziness, insomnia, nervousness, drowsiness, and lightheaded feeling; gastrointestinal disturbances (1.2%), primarily nausea; and miscellaneous disturbances (1.1%), primarily headache and fatigue. In addition, 3.4% of patients had multiple complaints, none of which could be characterized as primary.

Incidence in Controlled Clinical Trials The table that follows enumerates adverse events that occurred at a frequency of 1% or more among buspirone hydrochloride patients who participated in 4 week, controlled trials comparing buspirone with placebo. The frequencies were obtained from pooled data for 17 trials. The prescriber should be aware that these figures cannot be used to predict the incidence of side effects in the course of usual medical practice where patient characteristics and other factors differ from those which prevailed in the clinical trials.

Similarly, the cited frequencies cannot be compared with figures obtained from other clinical investigations involving different treatments, uses, and investigators. Comparison of the cited figures, however, does provide the prescribing physician with some basis for estimating the relative contribution of drug and nondrug factors to the side-effect incidence rate in the population studied. TREATMENT-EMERGENT ADVERSE EXPERIENCE INCIDENCE IN PLACEBO-CONTROLLED CLINICAL TRIALS* (Percent of Patients Reporting) * Events reported by at least 1% of buspirone patients are included. - Incidence less than 1%.

Adverse Experience Buspirone (n = 477) Placebo (n = 464) Cardiovascular Tachycardia/Palpitations 1 1 CNS Dizziness 12 3 Drowsiness 10 9 Nervousness 5 1 Insomnia 3 3 Lightheadedness 3 - Decreased Concentration 2 2 Excitement 2 - Anger/Hostility 2 - Confusion 2 - Depression 2 2 EENT Blurred Vision 2 - Gastrointestinal Nausea 8 5 Dry Mouth 3 4 Abdominal/Gastric Distress 2 2 Diarrhea 2 - Constipation 1 2 Vomiting 1 2 Musculoskeletal Musculoskeletal Aches/Pains 1 - Neurological Numbness 2 - Paresthesia 1 - Incoordination 1 - Tremor 1 - Skin Skin Rash 1 - Miscellaneous Headache 6 3 Fatigue 4 4 Weakness 2 - Sweating/Clamminess 1 - Other Events Observed During the Entire Premarketing Evaluation of Buspirone During its premarketing assessment, buspirone was evaluated in over 3500 subjects.

This section reports event frequencies for adverse events occurring in approximately 3000 subjects from this group who took multiple doses of buspirone in the dose range for which buspirone is being recommended (i.e., the modal daily dose of buspirone fell between 10 and 30 mg for 70% of the patients studied) and for whom safety data were systematically collected. The conditions and duration of exposure to buspirone varied greatly, involving well-controlled studies as well as experience in open and uncontrolled clinical settings.

As part of the total experience gained in clinical studies, various adverse events were reported. In the absence of appropriate controls in some of the studies, a causal relationship to buspirone hydrochloride treatment cannot be determined. The list includes all undesirable events reasonably associated with the use of the drug.

The following enumeration… [Excerpted — this section continues on DailyMed.]

Drug Interactions Psychotropic Agents MAO inhibitors : The use of monoamine oxidase inhibitors (MAOIs) intended to treat depression with buspirone or within 14 days of stopping treatment with buspirone is contraindicated because of an increased risk of serotonin syndrome and/or elevated blood pressure. The use of buspirone within 14 days of stopping an MAOI intended to treat depression is also contraindicated. Starting buspirone in a patient who is being treated with reversible MAOIs such as linezolid or intravenous methylene blue is also contraindicated because of an increased risk of serotonin syndrome.

(see WARNINGS, DOSAGE AND ADMINISTRATION AND CONCOMITANT DRUG ) Amitriptyline: After addition of buspirone to the amitriptyline dose regimen, no statistically significant differences in the steady-state pharmacokinetic 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 pharmacokinetic 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 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 pharmacokinetic 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. Itracona… [Excerpted — this section continues on DailyMed.]

PRECAUTIONS General Interference with Cognitive and Motor Performance Studies indicate that buspirone is less sedating than other anxiolytics and that it does not produce significant functional impairment. However, its CNS effects in any individual patient may not be predictable. Therefore, patients should be cautioned about operating an automobile or using complex machinery until they are reasonably certain that buspirone treatment does not affect them adversely.

While formal studies of the interaction of buspirone hydrochloride with alcohol indicate that buspirone does not increase alcohol-induced impairment in motor and mental performance, it is prudent to avoid concomitant use of alcohol and buspirone. Potential for Withdrawal Reactions in Sedative/Hypnotic/Anxiolytic Drug-Dependent Patients Because buspirone does not exhibit cross-tolerance with benzodiazepines and other common sedative/hypnotic drugs, it will not block the withdrawal syndrome often seen with cessation of therapy with these drugs.

Therefore, before starting therapy with buspirone, it is advisable to withdraw patients gradually, especially patients who have been using a CNS-depressant drug chronically, from their prior treatment. Rebound or withdrawal symptoms may occur over varying time 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 of irritability, 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 potential to cause acute and chronic changes in dopamine-mediated neurological function (e.g., dystonia, pseudo-parkinsonism, akathisia, and tardive dyskinesia). Clinical experience in controlled trials has failed to identify any significant neuroleptic-like activity; however, a syndrome of restlessness, appearing shortly after initiation of treatment, has been reported in some small fraction of buspirone-treated patients.

The syndrome may be explained in several ways. For example, buspirone may increase central noradrenergic 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 and instructions should be given to patients: Do not take a monoamine oxidase inhibitor (MAOI). Ask your healthcare provider or pharmacist if you are not sure if you take an MAOI, including the antibiotic linezolid. Do not take an MAOI within 2 weeks of stopping buspirone unless directed to do so by your physician Do not start buspirone if you stopped taking an MAOI in the last 2 weeks unless directed to do so by your physician.

Inform your physician about any medications, prescription or non-prescription, alcohol, or drugs that you are now taking or plan to take during your treatment with buspirone. Inform your physician if you are pregnant, or if you are planning to become pregnant, or if you become pregnant while you are taking buspirone. Inform your physician if you are breast-feeding an infant.

Until you experience how this medication affects you, do not drive a car or operate potentially dangerous machinery. You should take buspirone consistently, either always with or always without food. During your treatment with buspirone, avoid drinking large amounts of grapefruit juice.

Laboratory Tests There are no specific laboratory tests recommended. Drug Interactions Psychotropic Agents MAO inhibitors : The use of monoamine oxidase inhibitors (MAOIs) intended to treat depression with buspirone or within 14 days of stopping treatment with buspirone is cont… [Excerpted — this section continues on DailyMed.]

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 double-blind clinical investigations. None of the subjects were able to distinguish between buspirone 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 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 misuse or abuse (e.g., development of tolerance, incrementation of dose, drug-seeking behavior). Call your doctor for medical advice about side effects.

You may report side effects to Strides Pharma Inc. at 1-877-244-9825 or go to www.strides.com.