CLINICAL PHARMACOLOGY SECTION

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

The exact mechanism of the antidepressant action of bupropion is not known but is presumed to be related to noradrenergic and/or dopaminergic mechanisms. Bupropion is a relatively weak inhibitor of the neuronal reuptake of norepinephrine and dopamine and does not inhibit the reuptake of serotonin. Bupropion does not inhibit monoamine oxidase.

12.3 Pharmacokinetics

Bupropion is a racemic mixture. The pharmacological activity and pharmacokinetics of the individual enantiomers have not been studied. The mean elimination half-life (±SD) of bupropion after chronic dosing is 21 (±9) hours, and steady-state plasma concentrations of bupropion are reached within 8 days.

Absorption
The absolute bioavailability of bupropion hydrochloride tablets in humans has not been determined because an intravenous formulation for human use is not available. However, it appears likely that only a small proportion of any orally administered dose reaches the systemic circulation intact. In rat and dog studies, the bioavailability of bupropion ranged from 5% to 20%.

In humans, following oral administration of bupropion hydrochloride tablets, peak plasma bupropion concentrations are usually achieved within 2 hours. Plasma bupropion concentrations are dose-proportional following single doses of 100 to 250 mg; however, it is not known if the proportionality between dose and plasma level is maintained in chronic use.

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 seen with 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 as or higher than those of bupropion.

Following a single dose in humans, peak plasma concentrations of hydroxybupropion occur approximately 3 hours after administration of bupropion hydrochloride tablets and are approximately 10 times the peak level of the parent drug at steady state. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours, and its AUC at steady state is about 17 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of the hydroxybupropion metabolite. However, their elimination half-lives are longer, 33 (±10) and 37 (±13) hours, respectively, and steady-state AUCs are 1.5 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.

Specific Populations
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.

Patients with 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 trial, 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 tablets should be used with caution in patients with renal impairment and a reduced frequency and/or dose should be considered [see Use in Specific Populations ( 8.6)].

Patients with 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 volunteers 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 with 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 (t½) in subjects with mild-to-moderate hepatic cirrhosis. In subjects with severe hepatic cirrhosis, significant alterations in the pharmacokinetics of bupropion and its metabolites were seen (Table 3).

Table 3. Pharmacokinetics of Bupropion and Metabolites in Patients with Severe Hepatic Cirrhosis: Ratio Relative to Healthy Matched Controls

a = Difference.

Patients with Left Ventricular Dysfunction: During a chronic dosing trial with bupropion in 14 depressed subjects with left ventricular dysfunction (history of CHF or an enlarged heart on x-ray), there was no apparent effect on the pharmacokinetics of bupropion or its metabolites, compared with healthy volunteers.

Age: The effects of age on the pharmacokinetics of bupropion and its metabolites have not been fully characterized, but an exploration of steady- state bupropion concentrations from several depression efficacy trials involving subjects dosed in a range of 300 to 750 mg/day, on a 3-times daily schedule, revealed no relationship between age (18 to 83 years) and plasma concentration of bupropion. A single-dose pharmacokinetic trial demonstrated that the disposition of bupropion and its metabolites in elderly subjects was similar to that of younger subjects. These data suggest there is no prominent effect of age on bupropion concentration; however, another single- and multiple-dose pharmacokinetics trial suggested that the elderly are at increased risk for accumulation of bupropion and its metabolites [see Use in Specific Populations ( 8.5)].

Male and Female Patients: Pooled analysis of bupropion pharmacokinetic data from 90 healthy male and 90 healthy female volunteers revealed no sex-related differences in the peak plasma concentrations of bupropion. The mean systemic exposure (AUC) was approximately 13% higher in male volunteers compared with female volunteers. The clinical significance of this finding is unknown.

Smokers: The effects of cigarette smoking on the pharmacokinetics of bupropion were studied in 34 healthy male and female volunteers; 17 were chronic cigarette smokers and 17 were nonsmokers. Following oral administration of a single 150-mg dose of bupropion, there were no statistically significant differences in C max, half-life, T max, AUC, or clearance of bupropion or its active metabolites between smokers and nonsmokers.

Drug Interactions studies

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****Potential for Other Drugs to Affect Bupropion Hydrochloride Tablets: In vitro studies indicate that bupropion is primarily metabolized to hydroxybupropion by CYP2B6. Therefore, the potential exists for drug interactions between bupropion hydrochloride tablets and drugs that are inhibitors or inducers of CYP2B6. In addition, in vitro studies suggest that paroxetine, sertraline, norfluoxetine, fluvoxamine, and nelfinavir inhibit the hydroxylation of bupropion.

Inhibitors of CYP2B6: Ticlopidine, Clopidogrel: In a trial in healthy male volunteers, clopidogrel 75 mg once daily or ticlopidine 250 mg twice daily increased exposures (C max and AUC) of bupropion by 40% and 60% for clopidogrel, and by 38% and 85% for ticlopidine, respectively. The exposures (C max and AUC) of hydroxybupropion were decreased 50% and 52%, respectively, by clopidogrel, and 78% and 84%, respectively, by ticlopidine. This effect is thought to be due to the inhibition of the CYP2B6-catalyzed bupropion hydroxylation.

Prasugrel: Prasugrel is a weak inhibitor of CYP2B6. In healthy subjects, prasugrel increased bupropion C max and AUC values by 14% and 18%, respectively, and decreased C max and AUC values of hydroxybupropion, an active metabolite of bupropion, by 32% and 24%, respectively.

Cimetidine: The threohydrobupropion metabolite of bupropion does not appear to be produced by cytochrome P450 enzymes. The effects of concomitant administration of cimetidine on the pharmacokinetics of bupropion and its active metabolites were studied in 24 healthy young male volunteers. Following oral administration of bupropion 300 mg with and without cimetidine 800 mg, the pharmacokinetics of bupropion and hydroxybupropion were unaffected. However, there were 16% and 32% increases in the AUC and C max, respectively of the combined moieties of threohydrobupropion and erythrohydrobupropion.

Citalopram: Citalopram did not affect the pharmacokinetics of bupropion and its three metabolites.

Inducers of CYP2B6: Ritonavir and Lopinavir: In a healthy volunteer trial, ritonavir 100 mg twice daily reduced the AUC and C max of bupropion by 22% and 21%, respectively. The exposure of the hydroxybupropion metabolite was decreased by 23%, the threohydrobupropion decreased by 38%, and the erythrohydrobupropion decreased by 48%.

In a second healthy volunteer trial, ritonavir at a dose of 600 mg twice daily decreased the AUC and the C max of bupropion by 66% and 62%, respectively. The exposure of the hydroxybupropion metabolite was decreased by 78%, the threohydrobupropion decreased by 50%, and the erythrohydrobupropion decreased by 68%. In another healthy volunteer trial, lopinavir 400 mg/ritonavir 100 mg twice daily decreased bupropion AUC and C max by 57%. The AUC and C max of hydroxybupropion were decreased by 50% and 31%, respectively .

Efavirenz: In a trial in healthy volunteers, efavirenz 600 mg once daily for 2 weeks reduced the AUC and C max of bupropion by approximately 55% and 34%, respectively. The AUC of hydroxybupropion was unchanged, whereas C max of hydroxybupropion was increased by 50%.

Carbamazepine, Phenobarbital, Phenytoin: While not systematically studied, these drugs may induce the metabolism of bupropion.

Potential for Bupropion Hydrochloride Tablets to Affect Other Drugs

Animal data indicated that bupropion may be an inducer of drug-metabolizing enzymes in humans. In one trial, following chronic administration of bupropion 100 mg three times daily to 8 healthy male volunteers for 14 days, there was no evidence of induction of its own metabolism. Nevertheless, there may be potential for clinically important alterations of blood levels of co- administered drugs.

Drugs Metabolized by CYP2D6: In vitro, bupropion and its metabolites (erythrohydrobupropion, threohydrobupropion, hydroxybupropion) are CYP2D6 inhibitors. In a clinical trial of 15 male subjects (ages 19 to 35 years) who were extensive metabolizers of CYP2D6, bupropion 300 mg/day followed by a single dose of 50 mg desipramine increased the C max, AUC, and t 1/2 of desipramine by an average of approximately 2-, 5-, and 2-fold, respectively. The effect was present for at least 7 days after the last dose of bupropion. Concomitant use of bupropion with other drugs metabolized by CYP2D6 has not been formally studied.

Citalopram: Although citalopram is not primarily metabolized by CYP2D6, in one trial bupropion increased the C max and AUC of citalopram by 30% and 40%, respectively.

Lamotrigine: Multiple oral doses of bupropion had no statistically significant effects on the single-dose pharmacokinetics of lamotrigine in 12 healthy volunteers.

Digoxin: Literature data showed that digoxin exposure was decreased when a single oral dose of 0.5-mg digoxin was administered 24 hours after a single oral dose of extended-release 150-mg bupropion in healthy volunteers .

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WARNINGS AND PRECAUTIONS SECTION

Highlight: * 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 for the occurrence of such symptoms and instruct them to discontinue bupropion and contact a healthcare provider if they experience such adverse events. ( 5.2)

• Seizure risk: The risk is dose-related. Can minimize risk by gradually increasing the dose and limiting daily dose to 450 mg. Discontinue if seizure occurs. ( 4, 5.3, 7.3)
• Hypertension: bupropion hydrochloride tablets 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 WARNINGS AND PRECAUTIONS

5.1 Suicidal Thoughts and Behaviors in Children, Adolescents, and Young

Adults

Patients with 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 MDD and other psychiatric disorders. Short-term clinical trials did not show an increase in the risk of suicidality with antidepressants compared with placebo in adults beyond age 24; there was a reduction with antidepressants compared with 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 subjects. 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 subjects. There was considerable variation in risk of suicidality among drugs, but a tendency toward an increase in the younger subjects 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 subjects 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 Subjects

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****]****.**

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 MDD 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 tablets 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 tablets are not approved for smoking cessation treatment; however, it contains the same active ingredient as the smoking cessation medication ZYBAN ®. 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 worsening of their psychiatric illnesses. Observe patients for the occurrence of neuropsychiatric adverse events. Advise patients and caregivers that the patient should stop taking bupropion hydrochloride tablets and contact a healthcare provider immediately if agitation, depressed mood, or changes in behavior or thinking that are not typical for the patient are observed, or if the patient develops suicidal ideation or suicidal behavior. In many postmarketing cases, resolution of symptoms after discontinuation of bupropion was reported. However, the symptoms persisted in some cases; therefore, ongoing monitoring and supportive care should be provided until symptoms resolve.

5.3 Seizure

Bupropion hydrochloride tablets can cause seizure. The risk of seizure is dose-related. The dose should not exceed 450 mg/day. Increase the dose gradually. Discontinue bupropion hydrochloride tablets and do not restart treatment if the patient experiences a seizure.

The risk of seizures is also related to patient factors, clinical situations, and concomitant medications that lower the seizure threshold. Consider these risks before initiating treatment with bupropion hydrochloride tablets. Bupropion hydrochloride tablets are contraindicated in patients with a seizure disorder, current or prior diagnosis of anorexia nervosa or bulimia, or undergoing abrupt discontinuation of alcohol, benzodiazepines, barbiturates, and antiepileptic drugs [see Contraindications ( 4), Drug Interactions ( 7.3)] . The following conditions can also increase the risk of seizure: severe head injury; arteriovenous malformation; CNS tumor or CNS infection; severe stroke; concomitant use of other medications that lower the seizure threshold (e.g., other bupropion products, antipsychotics, tricyclic antidepressants, theophylline, and systemic corticosteroids); metabolic disorders (e.g., hypoglycemia, hyponatremia, severe hepatic impairment, and hypoxia); use of illicit drugs (e.g., cocaine); or abuse or misuse of prescription drugs such as CNS stimulants. Additional predisposing conditions include diabetes mellitus treated with oral hypoglycemic drugs or insulin; use of anorectic drugs; and excessive use of alcohol, benzodiazepines, sedative/hypnotics, or opiates.

Incidence of Seizure with Bupropion Use****
****Bupropion is associated with seizures in approximately 0.4% (4/1,000) of patients treated at doses up to 450 mg/day. The estimated seizure incidence for bupropion hydrochloride tablets increases almost 10-fold between 450 and 600 mg/day.

The risk of seizure can be reduced if the dose of bupropion hydrochloride tablets does not exceed 450 mg/day, given as 150 mg 3 times daily, and the titration rate is gradual.

5.4 Hypertension

Treatment with bupropion hydrochloride tablets can result in elevated blood pressure and hypertension. Assess blood pressure before initiating treatment with bupropion hydrochloride tablets, and monitor periodically during treatment. The risk of hypertension is increased if bupropion hydrochloride tablets are used concomitantly with MAOIs or other drugs that increase dopaminergic or noradrenergic activity [see Contraindications ( 4)].

Data from a comparative trial of the sustained-release formulation of bupropion HCl, nicotine transdermal system (NTS), the combination of sustained-release bupropion plus NTS, and placebo as an aid to smoking cessation suggest a higher incidence of treatment-emergent hypertension in patients treated with the combination of sustained-release bupropion and NTS. In this trial, 6.1% of subjects treated with the combination of sustained- release bupropion and NTS had treatment-emergent hypertension compared with 2.5%, 1.6%, and 3.1% of subjects treated with sustained-release bupropion, NTS, and placebo, respectively. The majority of these subjects had evidence of pre-existing hypertension. Three subjects (1.2%) treated with the combination of sustained-release bupropion and NTS and 1 subject (0.4%) treated with NTS had study medication discontinued due to hypertension compared with none of the subjects treated with sustained-release bupropion or placebo. Monitoring of blood pressure is recommended in patients who receive the combination of bupropion and nicotine replacement.

In a clinical trial of bupropion immediate-release in MDD subjects with stable congestive heart failure (N = 36), bupropion was associated with an exacerbation of pre-existing hypertension in 2 subjects, leading to discontinuation of bupropion treatment. There are no controlled trials assessing the safety of bupropion in patients with a recent history of myocardial infarction or unstable cardiac disease.

5.5 Activation of Mania/Hypomania

Antidepressant treatment can precipitate a manic, mixed, or hypomanic manic episode. The risk appears to be increased in patients with bipolar disorder or who have risk factors for bipolar disorder. Prior to initiating bupropion hydrochloride tablets, screen patients for a history of bipolar disorder and the presence of risk factors for bipolar disorder (e.g., family history of bipolar disorder, suicide, or depression). Bupropion hydrochloride tablets are not approved for use in treating bipolar depression.

5.6 Psychosis and Other Neuropsychiatric Reactions

Depressed patients treated with bupropion hydrochloride tablets have had a variety of neuropsychiatric signs and symptoms, including delusions, hallucinations, psychosis, concentration disturbance, paranoia, and confusion. Some of these patients had a diagnosis of bipolar disorder. In some cases, these symptoms abated upon dose reduction and/or withdrawal of treatment. Instruct patients to contact a healthcare professional if such reactions occur.

5.7 Angle-Closure Glaucoma

The pupillary dilation that occurs following use of many antidepressant drugs including bupropion hydrochloride tablets may trigger an angle-closure attack in a patient with anatomically narrow angles who does not have a patent iridectomy.

5.8 Hypersensitivity Reactions

Anaphylactoid/anaphylactic reactions have occurred during clinical trials with bupropion. Reactions have been characterized by pruritus, urticaria, angioedema, and dyspnea requiring medical treatment. In addition, there have been rare, spontaneous postmarketing reports of erythema multiforme, Stevens- Johnson syndrome, and anaphylactic shock associated with bupropion. Instruct patients to discontinue bupropion hydrochloride tablets and consult a healthcare provider if they develop an allergic or anaphylactoid/anaphylactic reaction (e.g., skin rash, pruritus, hives, chest pain, edema, and shortness of breath) during treatment. There are reports of arthralgia, myalgia, fever with rash and other serum sickness-like symptoms suggestive of delayed hypersensitivity.

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DRUG INTERACTIONS SECTION

Highlight: * CYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, and phenytoin) based on clinical response, 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)
• Digoxin: May decrease plasma digoxin levels. Monitor digoxin levels. ( 7.2)
• Drugs that lower seizure threshold: Dose bupropion hydrochloride tablets with caution. ( 5.3, 7.3)
• Dopaminergic drugs (levodopa and amantadine): CNS toxicity can occur when used concomitantly with bupropion hydrochloride tablets. ( 7.4)
• MAOIs: Increased risk of hypertensive reactions can occur when used concomitantly with bupropion hydrochloride tablets. ( 7.6)
• Drug-laboratory test interactions: Bupropion hydrochloride tablets can cause false-positive urine test results for amphetamines. ( 7.7)

7 DRUG INTERACTIONS

7.1 Potential for Other Drugs to Affect Bupropion Hydrochloride Tablets

Bupropion is primarily metabolized to hydroxybupropion by CYP2B6. Therefore, the potential exists for drug interactions between bupropion hydrochloride tablets and drugs that are inhibitors or inducers of CYP2B6.

Inhibitors of CYP2B6****
****Ticlopidine and Clopidogrel: Concomitant treatment with these drugs can increase bupropion exposure but decrease hydroxybupropion exposure. Based on clinical response, dosage adjustment of bupropion hydrochloride tablets 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 tablets may be necessary when coadministered with ritonavir, lopinavir, or efavirenz [see Clinical Pharmacology ( 12.3)] but should not exceed the maximum recommended dose.

Carbamazepine, Phenobarbital, Phenytoin: While not systematically studied, these drugs may induce the 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 Tablets to Affect Other Drugs

Drugs Metabolized by CYP2D6****
****Bupropion and its metabolites (erythrohydrobupropion, threohydrobupropion, hydroxybupropion) are CYP2D6 inhibitors. Therefore, coadministration of bupropion hydrochloride tablets 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, thioridazine), beta-blockers (e.g., metoprolol), and Type 1C antiarrhythmics (e.g., propafenone and flecainide). When used concomitantly with bupropion hydrochloride tablets, 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 tablets and such drugs may require increased doses of the drug [see Clinical Pharmacology ( 12.3)].

Digoxin
Coadministration of bupropion hydrochloride with digoxin may decrease plasma digoxin levels. Monitor plasma digoxin levels in patients treated concomitantly with bupropion hydrochloride and digoxin [see Clinical Pharmacology ( 12.3)] .

7.3 Drugs that Lower Seizure Threshold

Use extreme caution when coadministering bupropion hydrochloride tablets with other drugs that lower seizure threshold (e.g., other bupropion products, antipsychotics, antidepressants, theophylline, or systemic corticosteroids). Use low initial doses and increase the dose gradually [see Contraindications ( 4), 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 tablets 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 tablets. The consumption of alcohol during treatment with bupropion hydrochloride tablets 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 tablets. Conversely, at least 14 days should be allowed after stopping bupropion hydrochloride tablets before starting an MAOI antidepressant [see Dosage and Administration (2.4, 2.5), 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.

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DRUG ABUSE AND DEPENDENCE SECTION

9 DRUG ABUSE AND DEPENDENCE

9.1 Controlled Substance

Bupropion is not a controlled substance.

9.2 Abuse

Humans****
****Controlled clinical trials conducted in normal volunteers, in subjects with a history of multiple drug abuse, and in depressed subjects showed some increase in motor activity and agitation/excitement, often typical of central stimulant activity.

In a population of individuals experienced with drugs of abuse, a single oral dose of 400 mg of bupropion produced mild amphetamine-like activity as compared with placebo on the Morphine-Benzedrine Subscale of the Addiction Research Center Inventories (ARCI) and a score greater than placebo but less than 15 mg of the Schedule II stimulant dextroamphetamine on the Liking Scale of the ARCI. These scales measure general feelings of euphoria and drug liking which are often associated with abuse potential.

Findings in clinical trials, however, are not known to reliably predict the abuse potential of drugs. Nonetheless, evidence from single-dose trials does suggest that the recommended daily dosage of bupropion when administered orally in divided doses is not likely to be significantly reinforcing to amphetamine or CNS stimulant abusers. However, higher doses (which could not be tested because of the risk of seizure) might be modestly attractive to those who abuse CNS stimulant drugs.

Bupropion hydrochloride tablets are intended for oral use only. The inhalation of crushed tablets or injection of dissolved bupropion has been reported. Seizures and/or cases of death have been reported when bupropion has been administered intranasally or by parenteral injection.

Animals
Studies in rodents and primates demonstrated that bupropion exhibits some pharmacologic actions common to psychostimulants. In rodents, it has been shown to increase locomotor activity, elicit a mild stereotyped behavior response, and increase rates of responding in several schedule-controlled behavior paradigms. In primate models assessing the positive-reinforcing effects of psychoactive drugs, bupropion was self-administered intravenously. In rats, bupropion produced amphetamine-like and cocaine-like discriminative stimulus effects in drug discrimination paradigms used to characterize the subjective effects of psychoactive drugs.

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NONCLINICAL TOXICOLOGY SECTION

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Lifetime carcinogenicity studies were performed in rats and mice at bupropion doses up to 300 and 150 mg/kg/day, respectively. These doses are approximately 6 and 2 times the MRHD, respectively, on a mg/m 2 basis. In the rat study there was an increase in nodular proliferative lesions of the liver at doses of 100 to 300 mg/kg/day (approximately 2 to 6 times the MRHD on a mg/m 2 basis); lower doses were not tested. The question of whether or not such lesions may be precursors of neoplasms of the liver is currently unresolved. Similar liver lesions were not seen in the mouse study, and no increase in malignant tumors of the liver and other organs was seen in either study.

Bupropion produced a positive response (2 to 3 times control mutation rate) in 2 of 5 strains in the Ames bacterial mutagenicity assay. Bupropion produced an increase in chromosomal aberrations in 1 of 3 in vivo rat bone marrow cytogenetic studies.

There were no effects on male and female fertility when rats were administered oral doses of bupropion up to 300 mg/kg/day (approximately 6 times the MRHD on a mg/m 2 basis) to females prior to mating and either through Day 13 of gestation or through lactation, and to males for 60 days prior to and through mating. However, doses of 200 mg/kg/day (approximately 4 times the MRHD on a mg/m 2 basis) or greater, caused transient ataxia or behavioral changes in adult female rats. There were also no adverse effects on fertility, reproduction, or growth and development of male or female offspring.

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INFORMATION FOR PATIENTS SECTION

17 PATIENT COUNSELING INFORMATION

Advise the patient to read the FDA-approved patient labeling (Medication Guide).

Suicidal Thoughts and Behaviors

Instruct patients, their families, and/or their caregivers to be alert to the emergence of anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, mania, other unusual changes in behavior, worsening of depression, and suicidal ideation, especially early during antidepressant treatment and when the dose is adjusted up or down. Advise families and caregivers of patients to observe for the emergence of such symptoms on a day-to-day basis, since changes may be abrupt. Such symptoms should be reported to the patient’s prescriber or healthcare professional, especially if they are severe, abrupt in onset, or were not part of the patient’s presenting symptoms. Symptoms such as these may be associated with an increased risk for suicidal thinking and behavior and indicate a need for very close monitoring and possibly changes in the medication.

Neuropsychiatric Adverse Events and Suicide Risk in Smoking Cessation Treatment

Although bupropion hydrochloride tablets are not indicated for smoking cessation treatment, it contains the same active ingredient as ZYBAN ® which is approved for this use. Inform patients that some patients have experienced changes in mood (including depression and mania), psychosis, hallucinations, paranoia, delusions, homicidal ideation, aggression, hostility, agitation, anxiety, and panic, as well as suicidal ideation and suicide when attempting to quit smoking while taking bupropion.

Instruct patients to discontinue bupropion and contact a healthcare professional if they experience such symptoms [see Warnings and Precautions ( 5.2), Adverse Reactions ( 6.2)] .

Severe Allergic Reactions

Educate patients on the symptoms of hypersensitivity and to discontinue bupropion hydrochloride tablets if they have a severe allergic reaction.

Seizure

Instruct patients to discontinue and not restart bupropion hydrochloride tablets if they experience a seizure while on treatment. Advise patients that the excessive use or abrupt discontinuation of alcohol, benzodiazepines, antiepileptic drugs, or sedatives/hypnotics can increase the risk of seizure. Advise patients to minimize or avoid use of alcohol.

Angle-Closure Glaucoma

Patients should be advised that taking bupropion hydrochloride tablets can cause mild pupillary dilation, which in susceptible individuals, can lead to an episode of angle- closure glaucoma. Pre-existing glaucoma is almost always open-angle glaucoma because angle-closure glaucoma, when diagnosed, can be treated definitively with iridectomy. Open-angle glaucoma is not a risk factor for angle-closure glaucoma. Patients may wish to be examined to determine whether they are susceptible to angle closure, and have a prophylactic procedure (e.g., iridectomy), if they are susceptible [see Warnings and Precautions ( 5.7)] .

Bupropion-Containing Products

Educate patients that bupropion hydrochloride tablets contains the same active ingredient (bupropion hydrochloride) found in ZYBAN, which is used as an aid to smoking cessation treatment, and that bupropion hydrochloride tablets should not be used in combination with ZYBAN or any other medications that contain bupropion (such as WELLBUTRIN SR ®, the sustained-release formulation and WELLBUTRIN XL ® or FORFIVO XL ®, the extended-release formulations, and APLENZIN ®, the extended-release formulation of bupropion hydrobromide). In addition, there are a number of generic bupropion HCl products for the immediate-, sustained-, and extended-release formulations.

Potential for Cognitive and Motor Impairment

Advise patients that any CNS-active drug like bupropion hydrochloride tablets may impair their ability to perform tasks requiring judgment or motor and cognitive skills. Advise patients that until they are reasonably certain that bupropion hydrochloride tablets do not adversely affect their performance, they should refrain from driving an automobile or operating complex, hazardous machinery. Bupropion hydrochloride tablets may lead to decreased alcohol tolerance.

Concomitant Medications

Counsel patients to notify their healthcare provider if they are taking or plan to take any prescription or over-the-counter drugs because bupropion hydrochloride tablets and other drugs may affect each others’ metabolisms.

Pregnancy

Advise patients to notify their healthcare provider if they become pregnant or intend to become pregnant during therapy with bupropion hydrochloride tablets. Advise patients that there is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to bupropion hydrochloride tablets during pregnancy [see Use in Specific Populations (8.1)].

Storage Information

Instruct patients to store bupropion hydrochloride tablets at room temperature, between 59°F and 86°F (15°C to 30°C) and keep the tablets dry and out of the light.

Administration Information

Instruct patients to take bupropion hydrochloride tablets in equally divided doses 3 or 4 times a day, with doses separated by at least 6 hours to minimize the risk of seizure. Instruct patients if they miss a dose, not to take an extra tablet to make up for the missed dose and to take the next tablet at the regular time because of the dose-related risk of seizure. Instruct patients that bupropion hydrochloride tablets should be swallowed whole and not crushed, divided, or chewed. Bupropion hydrochloride tablets can be taken with or without food.

ZYBAN ® is a registered trademark of GlaxoSmithKline.

WELLBUTRIN SR ® is a registered trademark of GlaxoSmithKline.

WELLBUTRIN XL ® is a registered trademark of GlaxoSmithKline.

FORFIVO XL ® is a registered trademark of Edgemont Pharms LLC

APLENZIN ® is a registered trademark of Sanofi Aventis U.S. LLC

Dispense with Medication Guide available at www1.apotex.com/products/us****

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APOTEX INC.

BUPROPION HYDROCHLORIDE TABLETS, USP
75 mg and 100 mg

Revised: May 2021

Rev. 18

SPL MEDGUIDE SECTION

MEDICATION GUIDE

Bupropion Hydrochloride Tablets, USP
****(bue proe' pee on hye'' droe klor' ide).

Medication Guide available at www1.apotex.com/products/us

IMPORTANT: Be sure to read the three sections of this Medication Guide. The first section is about the risk of suicidal thoughts and actions with antidepressant medicines; the second section is about the risk of changes in thinking and behavior, depression and suicidal thoughts or actions with medicines used to quit smoking; and the third section is entitled "What Other Important Information Should I Know About Bupropion Hydrochloride Tablets?"

Antidepressant Medicines, Depression and Other Serious Mental Illnesses, and Suicidal Thoughts or Actions

This section of the Medication Guide is only about the risk of suicidal thoughts and actions with antidepressant medicines.

What is the most important information I should know about antidepressant medicines, depression and other serious mental illnesses, and suicidal thoughts or actions?

1.Antidepressant medicines may increase the risk of suicidal thoughts or actions in some children, teenagers, or young adults within the first few months of treatment.
2.** Depression or other serious mental illnesses are the most important causes of suicidal thoughts and actions. Some people may have a particularly high risk of having suicidal thoughts or actions.**These include****people who have (or have a family history of) bipolar illness (also called manic- depressive illness) or suicidal thoughts or actions.
**3.**How can I watch for and try to prevent suicidal thoughts and actions in myself or a family member?

• Pay close attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings. This is very important when an antidepressant medicine is started or when the dose is changed.
• Call your healthcare provider right away to report new or sudden changes in mood, behavior, thoughts, or feelings.
• Keep all follow-up visits with your healthcare provider as scheduled. Call the healthcare provider between visits as needed, especially if you have concerns about symptoms.

Call your healthcare provider right away if you or your family member has any of the following symptoms, especially if they are new, worse, or worry you:

• thoughts about suicide or dying
• attempts to commit suicide
• new or worse depression
• new or worse anxiety
• feeling very agitated or restless
• panic attacks
• trouble sleeping (insomnia)
• new or worse irritability
• acting aggressive, being angry, or violent
• acting on dangerous impulses
• an extreme increase in activity and talking (mania)
• other unusual changes in behavior or mood

What else do I need to know about antidepressant medicines?

*Never stop an antidepressant medicine without first talking to a healthcare provider.**Stopping an antidepressant medicine suddenly can causeother symptoms. *Antidepressants are medicines used to treat depression and other illnesses.**It is important to discuss all the risks of treating depression and alsothe risks of not treating it. Patients and their families or other caregivers should discuss all treatment choices with the healthcare provider, not just the use of antidepressants. *Antidepressant medicines have other side effects.**Talk to the healthcareprovider about the side effects of the medicine prescribed for you or your family member. *Antidepressant medicines can interact with other medicines.**Know all ofthe medicines that you or your family member takes. Keep a list of all medicines to show the healthcare provider. Do not start new medicines without first checking with your healthcare provider.

It is not known if bupropion hydrochloride tablets are safe and effective in children under the age of 18.

Quitting Smoking, Quit-Smoking Medications, Changes in Thinking and Behavior, Depression, and Suicidal Thoughts or Actions

This section of the Medication Guide is only about the risk of changes in thinking and behavior, depression and suicidal thoughts or actions with drugs used to quit smoking. Although bupropion hydrochloride tablets are not a treatment for quitting smoking, it contains the same active ingredient (bupropion hydrochloride) as ZYBAN ® which is used to help patients quit smoking.

Talk to your healthcare provider or your family member’s healthcare provider about:

• all risks and benefits of quit-smoking medicines.
• all treatment choices for quitting smoking.

When you try to quit smoking, with or without bupropion, you may have symptoms that may be due to nicotine withdrawal, including

• urge to smoke
• depressed mood
• trouble sleeping
• irritability
• frustration
• anger
• feeling anxious
• difficulty concentrating
• restlessness
• decreased heart rate
• increased appetite
• weight gain

Some people have even experienced suicidal thoughts when trying to quit smoking without medication. Sometimes quitting smoking can lead to worsening of mental health problems that you already have, such as depression.

Some people have had serious side effects while taking bupropion to help them quit smoking, including:

**New or worse mental health problems, such as changes in behavior or thinking, aggression, hostility, agitation, depression, or suicidal thoughts or actions.**Some people had these symptoms when they began taking bupropion, and others developed them after several weeks of treatment, or after stopping bupropion.

These symptoms happened more often in people who had a history of mental health problems before taking bupropion than in people without a history of mental health problems.

**Stop taking bupropion and call your healthcare provider right away if you, your family, or caregiver notice any of these symptoms.**Work with your healthcare provider to decide whether you should continue to take bupropion. In many people, these symptoms went away after stopping bupropion, but in some people symptoms continued after stopping bupropion. It is important for you to follow-up with your healthcare provider until your symptoms go away.

Before taking bupropion, tell your healthcare provider if you have ever had depression or other mental health problems. You should also tell your healthcare provider about any symptoms you had during other times you tried to quit smoking, with or without bupropion.

What Other Important Information Should I Know About Bupropion Hydrochloride Tablets?

*Seizures: There is a chance of having a seizure (convulsion, fit) with bupropion hydrochloride tablets, especially in people: * with certain medical problems. * who take certain medicines.

The chance of having seizures increases with higher doses of bupropion hydrochloride tablets. For more information, see the sections "Who should not take bupropion hydrochloride tablets?" and "What should I tell my healthcare provider before taking bupropion hydrochloride tablets?" Tell your healthcare provider about all of your medical conditions and all the medicines you take. Do not take any other medicines while you are taking bupropion hydrochloride tablets****unless your healthcare provider has said it is okay to take them.

**If you have a seizure while taking bupropion hydrochloride tablets, stop taking the tablets and call your healthcare provider right away.**Do not take bupropion hydrochloride tablets again****if you have a seizure.

*High blood pressure (hypertension). Some people get high blood pressure that can be severe, while taking bupropion hydrochloride tablets.**The chance ofhigh blood pressure may be higher if you also use nicotine replacement therapy (such as a nicotine patch) to help you stop smoking (see the section of this Medication Guide called "How should I take bupropion hydrochloride tablets?". *Manic episodes.**Some people may have periods of mania while takingbupropion hydrochloride tablets, including: * Greatly increased energy * Severe trouble sleeping * Racing thoughts * Reckless behavior * Unusually grand ideas * Excessive happiness or irritability * Talking more or faster than usual

If you have any of the above symptoms of mania, call your healthcare provider.

*Unusual thoughts or behaviors.**Some patients have unusual thoughts or**behaviors while taking bupropion hydrochloride tablets, including delusions (believe you are someone else), hallucinations (seeing or hearing things that are not there), paranoia (feeling that people are against you), or feeling confused. If this happens to you, call your healthcare provider. *Visual problems. * eye pain * changes in vision * swelling or redness in or around the eye

Only some people are at risk for these problems. You may want to undergo an eye examination to see if you are at risk and receive preventative treatment if you are.

*Severe allergic reactions. Some people can have severe allergic reactions to bupropion hydrochloride tablets. Stop taking bupropion hydrochloride tablets and call your healthcare provider right awayif you get a rash, itching, hives, fever,****swollen lymph glands, painful sores in the mouth or around the eyes, swelling of the lips or tongue, chest pain, or have trouble breathing. These could be signs of a serious allergic reaction.

What are bupropion hydrochloride tablets?

Bupropion hydrochloride tablets are a prescription medicine used to treat adults with a certain type of depression called major depressive disorder.

Who should not take bupropion hydrochloride tablets?

Do not take bupropion hydrochloride tablets if you

• have or had a seizure disorder or epilepsy.
• have or had an eating disorder such as anorexia nervosa or bulimia. are taking any other medicines that contain bupropion, including ZYBAN (used to help people stop smoking), WELLBUTRIN SR***®, WELLBUTRIN XL®, APLENZIN®, or FORFIVO XL®********.Bupropion is the same activeingredient that is in bupropion hydrochloride tablets.
• drink a lot of alcohol and abruptly stop drinking, or use medicines called sedatives (these make you sleepy), benzodiazepines, or anti-seizure medicines, and you stop using them all of a sudden.
• 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 bupropion hydrochloride tablets unless directed to do so by your healthcare provider.
  • do not start bupropion hydrochloride tablets if you stopped taking an MAOI in the last 2 weeks unless directed to do so by your healthcare provider.
• are allergic to the active ingredient in bupropion hydrochloride tablets, bupropion, or to any of the inactive ingredients. See the end of this Medication Guide for a complete list of ingredients in bupropion hydrochloride tablets.

What should I tell my healthcare provider before taking bupropion hydrochloride tablets?

Tell your healthcare provider if you have ever had depression, suicidal thoughts or actions, or other mental health problems. See "Antidepressant Medicines, Depression and Other Serious Mental Illnesses, and Suicidal Thoughts or Actions."

*Tell your healthcare provider about your other medical conditions including if you: * have liver problems, especially cirrhosis of the liver. * have kidney problems. * have, or have had, an eating disorder, such as anorexia nervosa or bulimia. * have had a head injury. * have had a seizure (convulsion, fit). * have a tumor in your nervous system (brain or spine). * have had a heart attack, heart problems, or high blood pressure. * are a diabetic taking insulin or other medicines to control your blood sugar. * drink alcohol. * abuse prescription medicines or street drugs. * are pregnant or plan to become pregnant. Talk to your healthcare provider about the risk to your unborn baby if you take bupropion hydrochloride tablets during pregnancy. * Tell your healthcare provider if you become pregnant or think you are pregnant during treatment with bupropion hydrochloride tablets. * If you become pregnant during treatment with bupropion hydrochloride tablets, talk to your healthcare provider about registering with the National Pregnancy Registry for Antidepressants. You can register by calling 1-844-405-6185. * are breastfeeding or plan to breastfeed during treatment with bupropion hydrochloride tablets. Bupropion hydrochloride tablets passes into your milk. Talk to your healthcare provider about the best way to feed your baby during treatment with bupropion hydrochloride tablets.

**Tell your healthcare provider about all the medicines you take,**including ****prescription, over-the-counter medicines, vitamins, and herbal supplements. Many medicines increase your chances of having seizures or other serious side effects if you take them while you are taking bupropion hydrochloride tablets.

How should I take bupropion hydrochloride tablets?

• Take bupropion hydrochloride tablets exactly as prescribed by your healthcare provider. Do not change your dose or stop taking bupropion hydrochloride tablets without talking with your healthcare provider first. *Swallow bupropion hydrochloride tablets whole. Do not chew, cut, or crush bupropion hydrochloride tablets.
• Take bupropion hydrochloride tablets at the same time each day.
• Take your doses of bupropion hydrochloride tablets at least 6 hours apart.
• You may take bupropion hydrochloride tablets with or without food.
• If you miss a dose, do not take an extra dose to make up for the dose you missed. Wait and take your next dose at the regular time.**This is veryimportant.**Too much bupropion hydrochloride tablets can increase your chance of having aseizure.
• If you take too much bupropion hydrochloride tablets, or overdose, call your local emergency room or poison control center right away. *Do not take any other medicines while taking bupropion hydrochloride tablets unless your healthcare provider has told you it is okay.
• If you are taking bupropion hydrochloride tablets for the treatment of major depressive disorder, it may take several weeks for you to feel that bupropion hydrochloride tablets are working. Once you feel better, it is important to keep taking bupropion hydrochloride tablets exactly as directed by your healthcare provider. Call your healthcare provider if you do not feel bupropion hydrochloride tablets are working for you.

What should I avoid while taking bupropion hydrochloride tablets?

• Limit or avoid using alcohol during treatment with bupropion hydrochloride tablets. If you usually drink a lot of alcohol, talk with your healthcare provider before suddenly stopping. If you suddenly stop drinking alcohol, you may increase your risk of having seizures.
• Do not drive a car or use heavy machinery until you know how bupropion hydrochloride tablets affect you. Bupropion hydrochloride tablets can affect your ability to do these things safely.

What are possible side effects of bupropion hydrochloride tablets?

Bupropion hydrochloride tablets can cause serious side effects. See the sections at the beginning of this Medication Guide for information about serious side effects of bupropion hydrochloride tablets.

The most common side effects of bupropion hydrochloride tablets include:

• nervousness
• dry mouth
• constipation
• headache
• nausea or vomiting
• dizziness
• heavy sweating
• shakiness (tremor)
• trouble sleeping
• blurred vision
• fast heartbeat

If you have nausea, take your medicine with food. If you have trouble sleeping, do not take your medicine too close to bedtime.

Tell your healthcare provider right away about any side effects that bother you.

These are not all the possible side effects of bupropion hydrochloride tablets. For more information, ask your healthcare provider or pharmacist.

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

You may also report side effects to Apotex Corp. at 1-800-706-5575.

How should I store bupropion hydrochloride tablets?

• Store bupropion hydrochloride tablets at room temperature between 68°F to 77°F (20°C to 25°C).
• Keep bupropion hydrochloride tablets dry and out of light.

Keep bupropion hydrochloride tablets and all medicines out of the reach of children.

General information about****the safe and effective use of ****bupropion hydrochloride tablets.

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use bupropion hydrochloride tablets for a condition for which it was not prescribed. Do not give bupropion hydrochloride tablets to other people, even if they have the same symptoms you have. It may harm them.

If you take a urine drug screening test, bupropion hydrochloride tablets may make the test result positive for amphetamines. If you tell the person giving you the drug screening test that you are taking bupropion hydrochloride tablets, they can do a more specific drug screening test that should not have this problem.

This Medication Guide summarizes important information about bupropion hydrochloride tablets. If you would like more information, talk with your healthcare provider. You can ask your healthcare provider or pharmacist for information about bupropion hydrochloride tablets that is written for healthcare professionals.

For more information about bupropion hydrochloride tablets, call 1-800-706-5575.

What are the ingredients in bupropion hydrochloride tablets?

Active ingredient
Bupropion hydrochloride.

Inactive ingredients
75-mg tablet –colloidal silicon dioxide, crospovidone, FD&C Yellow #6 Aluminum Lake, fumaric acid granular, hydroxypropyl cellulose, hypromellose, magnesium stearate, methylcellulose, polyethylene glycol and titanium dioxide.

100-mg tablet –colloidal silicon dioxide, crospovidone, D&C Red #7 Calcium Lake, fumaric acid granular, hydroxypropyl cellulose, hypromellose, magnesium stearate, methylcellulose, polyethylene glycol and titanium dioxide.

This Medication Guide has been approved by the U.S. Food and Drug Administration.

ZYBAN ® is a registered trademark of GlaxoSmithKline.

WELLBUTRIN SR ® is a registered trademark of GlaxoSmithKline.

WELLBUTRIN XL ® is a registered trademark of GlaxoSmithKline.

FORFIVO XL ® is a registered trademark of Edgemont Pharms LLC

APLENZIN ® is a registered trademark of Sanofi Aventis U.S. LLC

APOTEX INC.****

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BUPROPION HYDROCHLORIDE TABLETS, USP
75 mg and 100 mg

Revised: May 2021

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