Bupropion

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.

1 INDICATIONS AND USAGE Bupropion hydrochloride extended-release tablets (XL) are 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) ].

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 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 WELLBUTRIN ® Tablets or from WELLBUTRIN ® SR Sustained-Release Tablets When switching patients from WELLBUTRIN ® Tablets to bupropion hydrochloride extended-release tablets (XL) or from WELLBUTRIN ® SR 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) and 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 in patients with renal impairment (glomerular filtration rate less than 90 mL/min) [see Use in Specific Populations (8.6) and 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) and 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 MAO

6 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 Oryza Pharmaceuticals, Inc. at 1-866-637-4281, or FDA at 1-800-FDA-1088, or visit 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) have 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% Ir

7 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 extended-release tablets (XL) with caution. ( 5.3 , 7.3 ) Dopaminergic Drugs (levodopa and amantadine): CNS toxicity can occur when used concomitantly with bupropion hydrochloride extended-release tablets (XL). ( 7.4 ) MAOIs: Increased risk of hypertensive reactions can occur when used concomitantly with bupropion hydrochloride extended-release tablets (XL). ( 7.6 ) Drug-laboratory test interactions: Bupropion hydrochloride extended-release tablets (XL) can cause false-positive urine test results for amphetamines. ( 7.7 ) 7.1 Potential for Other Drugs to Affect Bupropion Hydrochloride Extended-Release Tablets (XL) Bupropion is primarily metabolized to hydroxybupropion by CYP2B6. Therefore, the potential exists for drug interactions between bupropion hydrochloride extended-release tablets (XL) 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 extended-release tablets (XL) 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 extended-release tablets (XL) 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 Extended-Release Tablets (XL) to Affect Other Drugs Drugs Metabolized by CYP2D6 Bupropion and its metabolites (erythrohydrobupropion, threohydrobupropion, hydroxybupropion) are CYP2D6 inhibitors. Therefore, coadministration of bupropion hydrochloride extended-release tablets (XL) 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 extended-release tablets (XL), 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 extended-release tablets (XL) 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 extended-release tablets (XL) 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 extended-release tablets (XL) 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 hyd