Bupropion Hydrochloride (xl)

INDICATIONS AND USAGE Bupropion hydrochloride extended-release tablets (XL) is an aminoketone antidepressant, indicated for: treatment of major depressive disorder (MDD) ( 1.1 ) prevention of seasonal affective disorder (SAD) ( 1.2 ) 1.1 Major Depressive Disorder (MDD) Bupropion hydrochloride extended-release tablets (XL) are indicated for the treatment of major depressive disorder (MDD), as defined by the Diagnostic and Statistical Manual (DSM). The efficacy of the immediate-release formulation of bupropion was established in two 4-week controlled inpatient trials and one 6-week controlled outpatient trial of adult patients with MDD. The efficacy of the sustained-release formulation of bupropion in the maintenance treatment of MDD was established in a long-term (up to 44 weeks), placebo-controlled trial in patients who had responded to bupropion in an 8-week study of acute treatment [see Clinical Studies(14.1) ]. 1.2 Seasonal Affective Disorder (SAD) Bupropion hydrochloride extended-release tablets (XL) are indicated for the prevention of seasonal major depressive episodes in patients with a diagnosis of seasonal affective disorder (SAD). The efficacy of bupropion hydrochloride extended-release tablets in the prevention of seasonal major depressive episodes was established in 3 placebo-controlled trials in adult outpatients with a history of MDD with an autumn-winter seasonal pattern as defined in the DSM [see Clinical Studies (14.2) ] .

DOSAGE AND ADMINISTRATION General Increase dose gradually to reduce seizure risk. ( 2.1 , 5.3 ) Periodically reassess the dose and need for maintenance treatment. ( 2.2 ) Major Depressive Disorder Starting dose: 150 mg once daily. Usual target dose: 300 mg once daily ( 2.2 ) After 4 days, may increase the dose to 300 mg once daily. ( 2.2 ) Seasonal Affective Disorder Initiate treatment in the autumn prior to onset of seasonal depressive symptoms. ( 2.3 ) Starting dose: 150 mg once daily. Usual target dose: 300 mg once daily. ( 2.3 ) After one week, may increase the dose to 300 mg once daily. ( 2.3 ) Continue treatment through the winter season. ( 2.3 ) Hepatic Impairment Moderate to severe hepatic impairment: 150 mg every other day ( 2.6 ) Mild hepatic impairment: Consider reducing the dose and/or frequency of dosing. ( 2.6 , 8.7 ) Renal Impairment Consider reducing the dose and/or frequency of dosing. ( 2.7 , 8.6 ) 2.1 General Instructions for Use To minimize the risk of seizure, increase the dose gradually [see Warnings and Precautions (5.3) ] . Bupropion hydrochloride extended-release tablets (XL) should be swallowed whole and not crushed, divided, or chewed. Bupropion hydrochloride extended-release tablets (XL) should be administered in the morning and may be taken with or without food. 2.2 Dosage for Major Depressive Disorder (MDD) The recommended starting dose for MDD is 150 mg once daily in the morning. After 4 days of dosing, the dose may be increased to the target dose of 300 mg once daily in the morning. It is generally agreed that acute episodes of depression require several months or longer of antidepressant treatment beyond the response in the acute episode. It is unknown whether the bupropion hydrochloride extended-release tablets (XL) dose needed for maintenance treatment is identical to the dose that provided an initial response. Periodically reassess the need for maintenance treatment and the appropriate dose for such treatment. 2.3 Dosage for Seasonal Affective Disorder (SAD) The recommended starting dose for SAD is 150 mg once daily. After 7 days of dosing, the dose may be increased to the target dose of 300 mg once daily in the morning. Doses above 300 mg of bupropion hydrochloride extended-release tablets (XL) were not assessed in the SAD trials. For the prevention of seasonal MDD episodes associated with SAD, initiate bupropion hydrochloride extended-release tablets (XL) in the autumn, prior to the onset of depressive symptoms. Continue treatment through the winter season. Taper and discontinue bupropion hydrochloride extended-release tablets (XL) in early spring. For patients treated with 300 mg per day, decrease the dose to 150 mg once daily before discontinuing bupropion hydrochloride extended-release tablets (XL). Individualize the timing of initiation, and duration of treatment should be individualized, based on the patient’s historical pattern of seasonal MDD episodes. 2.4 Switching Patients from Bupropion Hydrochloride Tablets or from Bupropion Hydrochloride Sustained-Release Tablets When switching patients from bupropion hydrochloride tablets to bupropion hydrochloride extended-release tablets (XL) or from bupropion hydrochloride sustained-release tablets to bupropion hydrochloride extended-release tablets (XL), give the same total daily dose when possible. 2.5 To Discontinue Bupropion Hydrochloride Extended-release Tablets (XL), Taper the Dose When discontinuing treatment in patients treated with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily, decrease the dose to 150 mg once daily prior to discontinuation. 2.6 Dosage Adjustment in Patients with Hepatic Impairment In patients with moderate to severe hepatic impairment (Child-Pugh score: 7 to 15), the maximum dose is 150 mg every other day . In patients with mild hepatic impairment (Child-Pugh score: 5 to 6), consider reducing the dose and/or frequency of dosing [see Use in Specific Populations (8.7) , Clinical Pharmacology (12.3) ]. 2.7 Dose Adjustment in Patients with Renal Impairment Consider reducing the dose and/or frequency of bupropion hydrochloride extended-release tablets (XL) in patients with renal impairment (glomerular filtration rate less than 90 mL/min) [see Use in Specific Populations(8.6) , Clinical Pharmacology (12.3) ]. 2.8 Switching a Patient to or from a Monoamine Oxidase Inhibitor (MAOI) Antidepressant At least 14 days should elapse between discontinuation of an MAOI intended to treat depression and initiation of therapy with bupropion hydrochloride extended-release tablets (XL). Conversely, at least 14 days should be allowed after stopping bupropion hydrochloride extended-release tablets (XL) before starting an MAOI antidepressant [see Contraindications(4) , Drug Interactions(7.6) ]. 2.9 Use of Bupropion Hydrochloride Extended-release Tablets (XL) with Reversible MAOIs such as Linezolid or Methylene Blue Do not start bupropion hydrochloride extended-release tablets (XL) in a patient who is being treated with a reversible MAOI such as linezolid or intravenous methylene blue. Drug interactions can increase risk of hypertensive reactions. In a patient who requires more urgent treatment of a psychiatric condition, non-pharmacological interventions, including hospitalization, should be considered [see Contraindications(4) ] . In some cases, a patient already receiving therapy with bupropion hydrochloride extended-release tablets (XL) may require urgent treatment with linezolid or intravenous methylene blue. If acceptable alternatives to linezolid or intravenous methylene blue treatment are not available and the potential benefits of linezolid or intravenous methylene blue treatment are judged to outweigh the risks of hypertensive reactions in a particular patient, bupropion hydrochloride extended-release tablets (XL) should be stopped promptly, and linezolid or intravenous methylene blue can be administered. The patient should be monitored for 2 weeks or until 24 hours after the last dose of linezolid or intravenous methylene blue, whichever comes first. Therapy with bupropion hydrochloride extended-release tablets (XL) may be resumed 24 hours after the last dose of linezolid or intravenous methylene blue. The risk of administering methylene blue by non-intravenous routes (such as oral tablets or by local injection) or in intravenous doses much lower than 1 mg per kg with bupropion hydrochloride extended-release tablets (XL) is unclear. The clinician should, nevertheless, be aware of the possibility of a drug interaction with such use [see Contraindications(4) , Drug Interactions (7.6) ] .

WARNINGS AND PRECAUTIONS Neuropsychiatric Adverse Events During Smoking Cessation: Postmarketing reports of serious or clinically significant neuropsychiatric adverse events have included changes in mood (including depression and mania), psychosis, hallucinations, paranoia, delusions, homicidal ideation, aggression, hostility, agitation, anxiety, and panic, as well as suicidal ideation, suicide attempt, and completed suicide. Observe patients attempting to quit smoking with bupropion hydrochloride extended-release tablets (XL) for the occurrence of such symptoms and instruct them to discontinue bupropion hydrochloride extended-release tablets (XL) and contact a healthcare provider if they experience such adverse events. ( 5.2 ) Seizure Risk: The risk is dose-related. Can minimize risk by limiting daily dose to 450 mg and gradually increasing the dose. Discontinue if seizure occurs. ( 4 , 5.3 , 7.3 ) Hypertension: Bupropion hydrochloride can increase blood pressure. Monitor blood pressure before initiating treatment and periodically during treatment. ( 5.4 ) Activation of Mania/Hypomania: Screen patients for bipolar disorder and monitor for these symptoms. ( 5.5 ) Psychosis and Other Neuropsychiatric Reactions: Instruct patients to contact a healthcare professional if such reactions occur. ( 5.6 ) Angle-Closure Glaucoma: Angle-closure glaucoma has occurred in patients with untreated anatomically narrow angles treated with antidepressants. ( 5.7 ) 5.1 Suicidal Thoughts and Behaviors in Children, Adolescents, and Young Adults Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders, and these disorders themselves are the strongest predictors of suicide. There has been a long-standing concern that antidepressants may have a role in inducing worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. Pooled analyses of short-term placebo-controlled trials of antidepressant drugs (Selective Serotonin Reuptake Inhibitors [SSRIs] and others) show that these drugs increase the risk of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults (ages 18 to 24) with major depressive disorder (MDD) and other psychiatric disorders. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction with antidepressants compared to placebo in adults aged 65 and older. The pooled analyses of placebo-controlled trials in children and adolescents with MDD, obsessive compulsive disorder (OCD), or other psychiatric disorders included a total of 24 short-term trials of 9 antidepressant drugs in over 4,400 patients. The pooled analyses of placebo-controlled trials in adults with MDD or other psychiatric disorders included a total of 295 short-term trials (median duration of 2 months) of 11 antidepressant drugs in over 77,000 patients. There was considerable variation in risk of suicidality among drugs, but a tendency toward an increase in the younger patients for almost all drugs studied. There were differences in absolute risk of suicidality across the different indications, with the highest incidence in MDD. The risk differences (drug vs. placebo), however, were relatively stable within age strata and across indications. These risk differences (drug-placebo difference in the number of cases of suicidality per 1,000 patients treated) are provided in Table 1 . Table 1: Risk Differences in the Number of Suicidality Cases by Age Group in the Pooled Placebo-Controlled Trials of Antidepressants in Pediatric and Adult Patients Age Range Drug-Placebo Difference in Number of Cases of Suicidality per 1,000 Patients Treated Increases Compared to Placebo <18 years 14 additional cases 18 to 24 years 5 additional cases Decreases Compared to Placebo 25 to 64 years 1 fewer case ≥65 years 6 fewer cases No suicides occurred in any of the pediatric trials. There were suicides in the adult trials, but the number was not sufficient to reach any conclusion about drug effect on suicide. It is unknown whether the suicidality risk extends to longer-term use, i.e., beyond several months. However, there is substantial evidence from placebo-controlled maintenance trials in adults with depression that the use of antidepressants can delay the recurrence of depression. All patients being treated with antidepressants for any indication should be monitored appropriately and observed closely for clinical worsening, suicidality, and unusual changes in behavior, especially during the initial few months of a course of drug therapy, or at times of dose changes, either increases or decreases [see Boxed Warning , Use in Specific Populations (8.4) ]. The following symptoms, anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, and mania, have been reported in adult and pediatric patients being treated with antidepressants for major depressive disorder as well as for other indications, both psychiatric and nonpsychiatric. Although a causal link between the emergence of such symptoms and either the worsening of depression and/or the emergence of suicidal impulses has not been established, there is concern that such symptoms may represent precursors to emerging suicidality. Consideration should be given to changing the therapeutic regimen, including possibly discontinuing the medication, in patients whose depression is persistently worse, or who are experiencing emergent suicidality or symptoms that might be precursors to worsening depression or suicidality, especially if these symptoms are severe, abrupt in onset, or were not part of the patient`s presenting symptoms. Families and caregivers of patients being treated with antidepressants for major depressive disorder or other indications, both psychiatric and nonpsychiatric, should be alerted about the need to monitor patients for the emergence of agitation, irritability, unusual changes in behavior, and the other symptoms described above, as well as the emergence of suicidality, and to report such symptoms immediately to healthcare providers. Such monitoring should include daily observation by families and caregivers. Prescriptions for bupropion hydrochloride should be written for the smallest quantity of tablets consistent with good patient management, in order to reduce the risk of overdose. 5.2 Neuropsychiatric Adverse Events and Suicide Risk in Smoking Cessation Treatment Bupropion hydrochloride extended-release tablets (XL) is not approved for smoking cessation treatment; however, bupropion HCl sustained-release is approved for this use. Serious neuropsychiatric adverse events have been reported in patients taking bupropion for smoking cessation. These postmarketing reports have included changes in mood (including depression and mania), psychosis, hallucinations, paranoia, delusions, homicidal ideation, aggression, hostility, agitation, anxiety, and panic, as well as suicidal ideation, suicide attempt, and completed suicide [see Adverse Reactions (6.2) ]. Some patients who stopped smoking may have been experiencing symptoms of nicotine withdrawal, including depressed mood. Depression, rarely including suicidal ideation, has been reported in smokers undergoing a smoking cessation attempt without medication. However, some of these adverse events occurred in patients taking bupropion who continued to smoke. Neuropsychiatric adverse events occurred in patients without and with pre-existing psychiatric disease; some patients experienced wors

CONTRAINDICATIONS Bupropion hydrochloride is contraindicated in patients with seizure disorder. Bupropion hydrochloride is contraindicated in patients with a current or prior diagnosis of bulimia or anorexia nervosa as a higher incidence of seizures was observed in such patients treated with bupropion hydrochloride [see Warnings and Precautions (5.3) ] . Bupropion hydrochloride is contraindicated in patients undergoing abrupt discontinuation of alcohol, benzodiazepines, barbiturates, and antiepileptic drugs [see Warnings and Precautions (5.3) , Drug Interactions (7.3) ] . The use of MAOIs (intended to treat psychiatric disorders) concomitantly with bupropion hydrochloride or within 14 days of discontinuing treatment with bupropion hydrochloride is contraindicated. There is an increased risk of hypertensive reactions when bupropion hydrochloride is used concomitantly with MAOIs. The use of bupropion hydrochloride within 14 days of discontinuing treatment with an MAOI is also contraindicated. Starting bupropion hydrochloride in a patient treated with reversible MAOIs such as linezolid or intravenous methylene blue is contraindicated. [see Dosage and Administration (2.9) , Warnings and Precautions (5.4) , Drug Interactions (7.6) ] . Bupropion hydrochloride extended-release tablets (XL) is contraindicated in patients with known hypersensitivity to bupropion or other ingredients of bupropion hydrochloride extended-release tablets (XL). Anaphylactoid/anaphylactic reactions and Stevens-Johnson syndrome have been reported [see Warnings and Precautions (5.8) ] . Seizure disorder. ( 4 , 5.3 ) Current or prior diagnosis of bulimia or anorexia nervosa ( 4 , 5.3 ) Abrupt discontinuation of alcohol, benzodiazepines, barbiturates, antiepileptic drugs. ( 4 , 5.3 ) Monoamine Oxidase Inhibitors (MAOIs): Do not use MAOIs intended to treat psychiatric disorders with bupropion hydrochloride or within 14 days of stopping treatment with bupropion hydrochloride. Do not use bupropion hydrochloride within 14 days of stopping an MAOI intended to treat psychiatric disorders. In addition, do not start bupropion hydrochloride in a patient who is being treated with linezolid or intravenous methylene blue. ( 4 , 7.6 ) Known hypersensitivity to bupropion or other ingredients of bupropion hydrochloride extended-release tablets (XL) ( 4 , 5.8 )

DRUG INTERACTIONS CYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, and phenytoin) based on clinical exposure, but should not exceed the maximum recommended dose. ( 7.1 ) Drugs metabolized by CYP2D6: Bupropion inhibits CYP2D6 and can increase concentrations of: antidepressants (e.g., venlafaxine, nortriptyline, imipramine, desipramine, paroxetine, fluoxetine, sertraline), antipsychotics (e.g., haloperidol, risperidone, thioridazine), beta-blockers (e.g., metoprolol), and Type 1C antiarrhythmics (e.g., propafenone, flecainide). Consider dose reduction when using with bupropion. ( 7.2 ). Drugs that lower seizure threshold: Dose bupropion hydrochloride with caution. ( 5.3 , 7.3 ) Dopaminergic Drugs (levodopa and amantadine): CNS toxicity can occur when used concomitantly with bupropion hydrochloride. ( 7.4 ) MAOIs: Increased risk of hypertensive reactions can occur when used concomitantly with bupropion hydrochloride. ( 7.6 ) Drug-laboratory test interactions: Bupropion hydrochloride can cause false-positive urine test results for amphetamines. ( 7.7 ) 7.1 Potential for Other Drugs to Affect Bupropion Hydrochloride Bupropion is primarily metabolized to hydroxybupropion by CYP2B6. Therefore, the potential exists for drug interactions between bupropion hydrochloride and drugs that are inhibitors or inducers of CYP2B6. Inhibitors of CYP2B6 Ticlopidine and Clopidogrel: Concomitant treatment with these drugs can increase bupropion exposures but decrease hydroxybupropion exposure. Based on clinical response, dosage adjustment of bupropion hydrochloride may be necessary when coadministered with CYP2B6 inhibitors (e.g., ticlopidine or clopidogrel) [see Clinical Pharmacology (12.3) ] . Inducers of CYP2B6 Ritonavir, Lopinavir, and Efavirenz: Concomitant treatment with these drugs can decrease bupropion and hydroxybupropion exposure. Dosage increase of bupropion hydrochloride may be necessary when coadministered with ritonavir, lopinavir, or efavirenz but should not exceed the maximum recommended dose [see Clinical Pharmacology (12.3) ] . Carbamazepine, Phenobarbital, Phenytoin: While not systemically studied, these drugs may induce metabolism of bupropion and may decrease bupropion exposure [see Clinical Pharmacology (12.3) ] . If bupropion is used concomitantly with a CYP inducer, it may be necessary to increase the dose of bupropion, but the maximum recommended dose should not be exceeded. 7.2 Potential for Bupropion Hydrochloride to Affect Other Drugs Drugs Metabolized by CYP2D6 Bupropion and its metabolites (erythrohydrobupropion, threohydrobupropion, hydroxybupropion) are CYP2D6 inhibitors. Therefore, coadministration of bupropion hydrochloride with drugs that are metabolized by CYP2D6 can increase the exposures of drugs that are substrates of CYP2D6. Such drugs include certain antidepressants (e.g., venlafaxine, nortriptyline, imipramine, desipramine, paroxetine, fluoxetine, and sertraline), antipsychotics (e.g., haloperidol, risperidone, and thioridazine), beta-blockers (e.g., metoprolol), and Type 1C antiarrhythmics (e.g., propafenone, and flecainide). When used concomitantly with bupropion hydrochloride, it may be necessary to decrease the dose of these CYP2D6 substrates, particularly for drugs with a narrow therapeutic index. Drugs that require metabolic activation by CYP2D6 to be effective (e.g., tamoxifen), theoretically could have reduced efficacy when administered concomitantly with inhibitors of CYP2D6 such as bupropion. Patients treated concomitantly with bupropion hydrochloride and such drugs may require increased doses of the drug [ see Clinical Pharmacology (12.3) ]. 7.3 Drugs That Lower Seizure Threshold Use extreme caution when coadministering bupropion hydrochloride with other drugs that lower the seizure threshold (e.g., other bupropion products, antipsychotics, antidepressants, theophylline, or systemic corticosteroids). Use low initial doses of bupropion hydrochloride and increase the dose gradually [see Warnings and Precautions (5.3) ] . 7.4 Dopaminergic Drugs (Levodopa and Amantadine) Bupropion, levodopa, and amantadine have dopamine agonist effects. CNS toxicity has been reported when bupropion was coadministered with levodopa or amantadine. Adverse reactions have included restlessness, agitation, tremor, ataxia, gait disturbance, vertigo, and dizziness. It is presumed that the toxicity results from cumulative dopamine agonist effects. Use caution when administering bupropion hydrochloride concomitantly with these drugs. 7.5 Use with Alcohol In postmarketing experience, there have been rare reports of adverse neuropsychiatric events or reduced alcohol tolerance in patients who were drinking alcohol during treatment with bupropion hydrochloride extended-release tablets (XL). The consumption of alcohol during treatment with bupropion hydrochloride extended-release tablets (XL) should be minimized or avoided. 7.6 MAO Inhibitors Bupropion inhibits the reuptake of dopamine and norepinephrine. Concomitant use of MAOIs and bupropion is contraindicated because there is an increased risk of hypertensive reactions if bupropion is used concomitantly with MAOIs. Studies in animals demonstrate that the acute toxicity of bupropion is enhanced by the MAO inhibitor phenelzine. At least 14 days should elapse between discontinuation of an MAOI intended to treat depression and initiation of treatment with bupropion hydrochloride. Conversely, at least 14 days should be allowed after stopping bupropion hydrochloride before starting an MAOI antidepressant [ see Dosage and Administration ( 2.8 , 2.9 ), Contraindications (4) ]. 7.7 Drug-Laboratory Test Interactions False-positive urine immunoassay screening tests for amphetamines have been reported in patients taking bupropion. This is due to lack of specificity of some screening tests. False-positive test results may result even following discontinuation of bupropion therapy. Confirmatory tests, such as gas chromatography/mass spectrometry, will distinguish bupropion from amphetamines.

ADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the labeling: Suicidal thoughts and behaviors in children, adolescents, and young adults [see Warnings and Precautions (5.1) ] Neuropsychiatric adverse events and suicide risk in smoking cessation treatment [see Warnings and Precautions (5.2) ] Seizure [see Warnings and Precautions (5.3) ] Hypertension [see Warnings and Precautions (5.4) ] Activation of mania or hypomania [see Warnings and Precautions (5.5) ] Psychosis and other neuropsychiatric events [see Warnings and Precautions (5.6) ] Angle-Closure Glaucoma [see Warnings and Precautions (5.7) ] Hypersensitivity reactions [see Warnings and Precautions (5.8) ] Most common adverse reactions are (incidence ≥5%; ≥2× placebo rate): dry mouth, nausea, insomnia, dizziness, pharyngitis, abdominal pain, agitation, anxiety, tremor, palpitation, sweating, tinnitus, myalgia, anorexia, urinary frequency, rash. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Chartwell RX, LLC. at 1-845-232-1683 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Commonly Observed Adverse Reactions in Controlled Clinical Trials of Sustained-Release Bupropion Hydrochloride Adverse reactions that occurred in at least 5% of patients treated with bupropion HCl sustained-release (300 mg and 400 mg per day) and at a rate at least twice the placebo rate are listed below. 300 mg/day of bupropion HCl sustained-release : anorexia, dry mouth, rash, sweating, tinnitus, and tremor. 400 mg/day of bupropion HCl sustained-release : abdominal pain, agitation, anxiety, dizziness, dry mouth, insomnia, myalgia, nausea, palpitation, pharyngitis, sweating, tinnitus, and urinary frequency. Bupropion hydrochloride extended-release tablets (XL) has been demonstrated to have similar bioavailability both to the immediate-release and sustained-release formulations of bupropion. The information included under this subsection and under subsection 6.2 is based primarily on data from controlled clinical trials with the sustained-release and extended-release formulations of bupropion hydrochloride. Major Depressive Disorder Adverse Reactions Leading to Discontinuation of Treatment with Bupropion HCl Immediate-Release, Bupropion HCl Sustained-Release, and Bupropion HCl Extended-Release in Major Depressive Disorder Trials In placebo-controlled clinical trials with bupropion HCl sustained-release, 4%, 9%, and 11% of the placebo, 300 mg/day and 400 mg/day groups, respectively, discontinued treatment because of adverse reactions. The specific adverse reactions leading to discontinuation in at least 1% of the 300 mg/day or 400 mg/day groups and at a rate at least twice the placebo rate are listed in Table 2 . Table 2: Treatment Discontinuation Due to Adverse Reactions in Placebo-Controlled Trials in MDD Adverse Reaction Term Placebo (n=385) Bupropion HCl Sustained-Release 300 mg/day (n=376) Bupropion HCl Sustained-Release 400 mg/day (n=114) Rash 0.0% 2.4% 0.9% Nausea 0.3% 0.8% 1.8% Agitation 0.3% 0.3% 1.8% Migraine 0.3% 0.0% 1.8% In clinical trials with bupropion HCl immediate-release, 10% of patients and volunteers discontinued due to an adverse reaction. Reactions resulting in discontinuation (in addition to those listed above for the sustained-release formulation) included vomiting, seizures, and sleep disturbances. Adverse Reactions Occurring at an Incidence of >1% in Patients Treated with Bupropion HCl Immediate-Release or Bupropion HCl Sustained-Release in MDD Table 3 summarizes the adverse reactions that occurred in placebo-controlled trials in patients treated with bupropion HCl sustained-release 300 mg/day and 400 mg/day. These include reactions that occurred in either the 300 mg or 400 mg group at an incidence of 1% or more and were more frequent than in the placebo group. Table 3: Adverse Reactions in Placebo-Controlled Trials in Patients with MDD Body System/ Adverse Reaction Placebo (n=385) Bupropion HCl Sustained-Release 300 mg/day (n=376) Bupropion HCl Sustained-Release 400 mg/day (n=114) Body (General) Headache 23% 26% 25% Infection 6% 8% 9% Abdominal pain 2% 3% 9% Asthenia 2% 2% 4% Chest pain 1% 3% 4% Pain 2% 2% 3% Fever - 1% 2% Cardiovascular Palpitation 2% 2% 6% Flushing - 1% 4% Migraine 1% 1% 4% Hot flashes 1% 1% 3% Digestive Dry mouth 7% 17% 24% Nausea 8% 13% 18% Constipation 7% 10% 5% Diarrhea 6% 5% 7% Anorexia 2% 5% 3% Vomiting 2% 4% 2% Dysphagia 0% 0% 2% Musculoskeletal Myalgia 3% 2% 6% Arthralgia 1% 1% 4% Arthritis 0% 0% 2% Twitch - 1% 2% Nervous System Insomnia 6% 11% 16% Dizziness 5% 7% 11% Agitation 2% 3% 9% Anxiety 3% 5% 6% Tremor 1% 6% 3% Nervousness 3% 5% 3% Somnolence 2% 2% 3% Irritability 2% 3% 2% Memory decreased 1% - 3% Paresthesia 1% 1% 2% Central nervous system stimulation 1% 2% 1% Respiratory Pharyngitis 2% 3% 11% Sinusitis 2% 3% 1% Increased cough 1% 1% 2% Skin Sweating 2% 6% 5% Rash 1% 5% 4% Pruritus 2% 2% 4% Urticaria 0% 2% 1% Special Senses Tinnitus 2% 6% 6% Taste perversion - 2% 4% Blurred vision or diplopia 2% 3% 2% Urogenital Urinary frequency 2% 2% 5% Urinary urgency 0% - 2% Vaginal hemorrhage 1 - 0% 2% Urinary tract infection - 2 1% 0% 1 Incidence based on the number of female patients. 2 Hyphen denotes adverse reactions occurring in greater than 0 but less than 0.5% of patients The following additional adverse reactions occurred in controlled trials of bupropion HCl immediate-release (300 to 600 mg per day) at an incidence of at least 1% more frequently than in the placebo group were: cardiac arrhythmia (5% vs. 4%), hypertension (4% vs. 2%), hypotension (3% vs. 2%), menstrual complaints (5% vs. 1%), akathisia (2% vs. 1%), impaired sleep quality (4% vs. 2%), sensory disturbance (4% vs. 3%), confusion (8% vs. 5%), decreased libido (3% vs. 2%), hostility (6% vs. 4%), auditory disturbance (5% vs. 3%), and gustatory disturbance (3% vs. 1%). Seasonal Affective Disorder In placebo-controlled clinical trials in SAD, 9% of patients treated with bupropion hydrochloride extended-release tablets (XL) and 5% of patients treated with placebo discontinued treatment because of adverse reactions. The adverse reactions leading to discontinuation in at least 1% of patients treated with bupropion and at a rate numerically greater than the placebo rate were insomnia (2% vs. <1%) and headache (1% vs. <1%). Table 4 summarizes the adverse reactions that occurred in patients treated with bupropion hydrochloride extended-release tablets (XL) for up to approximately 6 months in 3 placebo-controlled trials. These include reactions that occurred at an incidence of 2% or more and were more frequent than in the placebo group. Table 4: Adverse Reactions in Placebo-Controlled Trials in Patients with SAD System Organ Class/ Preferred Term Placebo (n=511) Bupropion HCl Extended-Release (n=537) Gastrointestinal Disorder Dry mouth 15% 26% Nausea 8% 13% Constipation 2% 9% Flatulence 3% 6% Abdominal pain <1% 2% Nervous System Disorders Headache 26% 34% Dizziness 5% 6% Tremor <1% 3% Infections and Infestations Nasopharyngitis 12% 13% Upper respiratory tract infection 8% 9% Sinusitis 4% 5% Psychiatric Disorders Insomnia 13% 20% Anxiety 5% 7% Abnormal dreams 2% 3% Agitation <1% 2% Musculoskeletal and Connective Tissue Disorders Myalgia 2% 3% Pain in extremity 2% 3% Respiratory, Thoracic, and Mediastinal Disorders Cough 3% 4% General Disorders and Administration Site Conditions Feeling jittery 2% 3% Skin and Subcutaneous Tissue Disorders Rash 2% 3% Metabolism and Nutrition Disorders Decreased appetite 1% 4% Reproductive System and Breast Disorders Dysmenorrhea <1% 2% Ear and Labyrinth Disorders Tinnitus <1% 3% Vascular Disorders Hypertension 0% 2% Changes in Body

CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The mechanism of action of bupropion is unknown, as is the case with other antidepressants. However, it is presumed that this action is mediated by noradrenergic and/or dopaminergic mechanisms. Bupropion is a relatively weak inhibitor of the neuronal uptake of norepinephrine and dopamine and does not inhibit monoamine oxidase or the reuptake of serotonin. 12.3 Pharmacokinetics Bupropion is a racemic mixture. The pharmacologic activity and pharmacokinetics of the individual enantiomers have not been studied. Following chronic dosing, the mean steady-state plasma concentration of bupropion was reached within 8 days. The mean elimination half-life (±SD) of bupropion is 21 (±9) hours. In a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL), 300 mg once-daily to the immediate-release formulation of bupropion at 100 mg 3 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion). Additionally, in a study comparing 14-day dosing with bupropion hydrochloride extended-release tablets (XL) 300 mg once daily to the sustained-release formulation of bupropion at 150 mg 2 times daily, equivalence was demonstrated for peak plasma concentration and area under the curve for bupropion and the three metabolites. Absorption Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion. Distribution In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg/mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that of bupropion. Metabolism Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert -butyl group of bupropion, and the amino-alcohol isomers threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance, because the plasma concentrations of the metabolites are as high or higher than those of bupropion. At steady state, peak plasma concentration of hydroxybupropion occurred approximately 7 hours after administration of bupropion hydrochloride extended-release tablets (XL), and it was approximately 7 times the peak level of the parent drug. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours, and its AUC at steady state is about 13 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of hydroxybupropion. However, the elimination half-lives of erythrohydrobupropion and threohydrobupropion are longer, approximately 33 (±10) and 37 (±13) hours, respectively, and steady-state AUCs were 1.4 and 7 times that of bupropion, respectively. Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg/day. Elimination Following oral administration of 200 mg of 14C-bupropion in humans, 87% and 10% of the radioactive dose were recovered in the urine and feces, respectively. Only 0.5% of the oral dose was excreted as unchanged bupropion. Population Subgroups Factors or conditions altering metabolic capacity (e.g., liver disease, congestive heart failure [CHF], age, concomitant medications, etc.) or elimination may be expected to influence the degree and extent of accumulation of the active metabolites of bupropion. The elimination of the major metabolites of bupropion may be affected by reduced renal or hepatic function, because they are moderately polar compounds and are likely to undergo further metabolism or conjugation in the liver prior to urinary excretion. Renal Impairment There is limited information on the pharmacokinetics of bupropion in patients with renal impairment. An inter-trial comparison between normal subjects and subjects with end-stage renal failure demonstrated that the parent drug C max and AUC values were comparable in the 2 groups, whereas the hydroxybupropion and threohydrobupropion metabolites had a 2.3- and 2.8-fold increase, respectively, in AUC for subjects with end-stage renal failure. A second study, comparing normal subjects and subjects with moderate-to-severe renal impairment (GFR 30.9 ± 10.8 mL/min) showed that after a single 150 mg dose of sustained-release bupropion, exposure to bupropion was approximately 2-fold higher in subjects with impaired renal function, while levels of the hydroxybupropion and threo/erythrohydrobupropion (combined) metabolites were similar in the 2 groups. Bupropion is extensively metabolized in the liver to active metabolites, which are further metabolized and subsequently excreted by the kidneys. The elimination of the major metabolites of bupropion may be reduced by impaired renal function. Bupropion hydrochloride should be used with caution in patients with renal impairment, and a reduced frequency and/or dose should be considered [see Dosage and Administration (2.7) , Use in Specific Populations (8.6) ]. Hepatic Impairment The effect of hepatic impairment on the pharmacokinetics of bupropion was characterized in 2 single-dose trials, one in subjects with alcoholic liver disease and one in subjects with mild to severe cirrhosis. The first trial demonstrated that the half-life of hydroxybupropion was significantly longer in 8 subjects with alcoholic liver disease than in 8 healthy volunteers (32±14 hours versus 21±5 hours, respectively). Although not statistically significant, the AUCs for bupropion and hydroxybupropion were more variable and tended to be greater (by 53% to 57%) in patients with alcoholic liver disease. The differences in half-life for bupropion and the other metabolites in the 2 groups were minimal. The second trial demonstrated no statistically significant differences in the pharmacokinetics of bupropion and its active metabolites in 9 subjects with mild to moderate hepatic cirrhosis compared to 8 healthy volunteers. However, more variability was observed in some of the pharmacokinetic parameters for bupropion (AUC, C max , and T max ) and its active metabolites (t 1/2 ) in subjects with mild to moderate hepatic cirrhosis. In addition, in patients with severe hepatic cirrhosis, the bupropion C max and AUC were substantially increased (mean difference: by approximately 70% and 3-fold, respectively) and more variable when compared to values in healthy volunteers; the mean bupropion half-life was also longer (29 hours in subjects with severe hepatic cirrhosis vs. 19 hours in healthy subjects). For the metabolite hydroxybupropion, the mean C max was approximately 69% lower. For the combined amino-alcohol isomers threohydrobupropion and erythrohydrobupropion, the mean C max was approximately 31% lower. The mean AUC increased by about 1½-fold for hydroxybupropion