Forma Farmacéutica
Tablet
Vía de Administración
ORAL
About This Medication
11. DESCRIPTION Bupropion hydrochloride extended-release tablets (XL), is an antidepressant of the aminoketone class, is chemically unrelated to tricyclic, tetracyclic, selective serotonin re-uptake inhibitor, or other known antidepressant agents. Its structure closely resembles that of diethylpropion; it is related to phenylethylamines. It is designated as (±)-1-(3-chorophenyl)-2-[(1,1-dimethylethyl)amino]-1propanone hydrochloride The molecular weight is 276.2. The molecular formula is C 13 H 18 ClNO•HCl. Bupropion hydrochloride, USP powder is white, crystalline, and highly soluble in water, in 0.1 N hydrochloric acid, and in alcohol. It has a bitter taste and produces the sensation of local anesthesia on the oral mucosa. The structural formula is: Each bupropion hydrochloride extended-release tablets, USP (XL) intended for oral administration contains 300 mg of bupropion hydrochloride. In addition, each tablet contains the following inactive ingredients: ethyl cellulose, hypromellose, magnesium stearate, methacrylic acid copolymer dispersion, polyethylene glycol, povidone, silicon dioxide, triethyl citrate. The tablet is printed with black pharmaceutical ink which contains ammonium hydroxide, butyl alcohol, iron oxide black, isopropyl alcohol, propylene glycol and shellac. The insoluble shell of the extended-release tablet may remain intact during gastrointestinal transit and is eliminated in the feces. The product meets USP Dissolution Test 14. Bupropion hydrochloride extended-release tablets, USP (XL)
Principios Activos
| Ingrediente |
Concentración |
| Bupropion Hydrochloride |
- |
Indicaciones y Uso
1. INDICATIONS AND USAGE Bupropion hydrochloride extended-release tablets, USP (XL) is an aminoketone antidepressant, indicated for the treatment of major depressive disorder (MDD) and prevention of seasonal affective disorder (SAD). Periodically reevaluate long-term usefulness for the individual patient. ( 1 ) 1.1 Major Depressive Disorder Bupropion hydrochloride extended-release tablets, USP (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 Bupropion hydrochloride extended-release tablets, USP (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 ) ].
Cómo funciona
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 re-uptake of serotonin.
Dosificación y Administración
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/day 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: • Initiative 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 Impairmen t: • 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 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 ) 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 (XL) in patients with renal impairment (Glomerular Filtration Rate < 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 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/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 ) and Drug Interactions ( 7.6 ) ].
Side Effects Overview
6. ADVERSE REACTIONS 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 Zydus Pharmaceuticals USA Inc. at 1-877-993-8779 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 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 symptoms 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 ) ] 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 clinical 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 hydrochloride 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 hydrochloride sustained-release: anorexia, dry mouth, rash, sweating, tinnitus, and tremor. 400 mg/day of bupropion hydrochloride 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 the 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 hydrochloride Immediate-Release, Bupropion hydrochloride Sustained-Release, and Bupropion hydrochloride Extended-Release in Major Depressive Disorder Trials In placebo-controlled clinical trials with bupropion hydrochloride 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 Hydrochloride Sustained-Release 300 mg/day (n=376) Bupropion Hydrochloride Sustained-Release 400 mg/day (n=114) Rash 0% 2.4% 0.9% Nausea 0.3% 0.8% 1.8% Agitation 0.3% 0.3% 1.8% Migraine 0.3% 0% 1.8% In clinical trials with bupropion hydrochloride 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 hydrochloride Immediate-Release or Bupropion hydrochloride Sustained-Release in MDD Table 3 summarizes the adverse reactions that occurred in placebo-controlled trials in patients treated with bupropion hydrochloride 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 are included. Table 3Adverse Reactions in Placebo-Controlled Trials in Patients with MDD * Incidence based on the number of female patients. † Hyphen denotes adverse reactions occurring in greater than 0 but less than 0.5% of patients Body System/ Adverse Reaction Placebo (n=385) Bupropion Hydrochloride Sustained-Release 300 mg/day (n=376) Bupropion Hydrochloride 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% Pruritis 2% 2% 4% Urticaria 0% 2% 1% Special Senses Tinnitus 2% 6% 6% Taste perversion - 2% 4% Blurred vision of diplopia 2% 3% 2% Urogenital Urinary frequency 2% 2% 5% Urinary urgency 0% - 2% Vaginal hemorrhage* - 0% 2% Urinary Tract Infection - † 1% 0% The following additional adverse reactions occurred in controlled trials of bupropion hydrochloride 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 Hydrochloride 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 Weight Table 5 presents the incidence of body weight changes (≥ 5 lbs) in the short-term MDD trials using bupropion hydrochloride sustained-release. There was a dose-related decrease in body weight. Table 5 Incidence of Weight Gain or Weight Loss (≥ 5 lbs.) in MDD Trials Using Bupropion hydrochloride Sustained-Release Weight Change Bupropion Hydrochloride Sustained-Release 300 mg/day (n=339) Bupropion Hydrochloride Sustained-Release 400 mg/day (n=112) Placebo (n=347) Gained > 5 lbs 3% 2% 4% Lost > 5 lbs 14% 19% 6% Table 6 presents the incidence of body weight changes (≥ 5 lbs) in the 3 SAD trials using bupropion hydrochloride extended-release. A higher proportion of subjects in the bupropion group (23%) had a weight loss ≥ 5 lbs., compared to the placebo group (11%). These were relatively long-term trials (up to 6 months). Table 6 Incidence of Weight Gain or Weight Loss (≥ 5 lbs) in SAD Trials Using Bupropion Hydrochloride Extended-Release Weight Change Bupropion Hydrochloride Extended-Release 150 to 300 mg/day (n=537) Placebo (n=511) Gained > 5 lbs 11% 21% Lost > 5 lbs 23% 11% 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of bupropion hydrochloride extended-release tablets (XL). Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Body (General) Chills, facial edema, edema, peripheral edema, musculoskeletal chest pain, photosensitivity, and malaise. Cardiovascular Postural hypotension, hypertension, stroke, vasodilation, syncope, complete atrioventricular block, extrasystoles, myocardial infarction, phlebitis, and pulmonary embolism. Digestive Abnormal liver function, bruxism, gastric reflux, gingivitis, glossitis, increased salivation, jaundice, mouth ulcers, stomatitis, thirst, edema of tongue, colitis, esophagitis, gastrointestinal hemorrhage, gum hemorrhage, hepatitis, intestinal perforation, liver damage, pancreatitis, and stomach ulcer. Endocrine Hyperglycemia, hypoglycemia, and syndrome of inappropriate antidiuretic hormone secretion. Hemic and Lymphatic Ecchymosis, anemia, leukocytosis, leukopenia, lymphadenopathy, pancytopenia, and thrombocytopenia. Altered PT and/or INR, associated with hemorrhagic or thrombotic complications, were observed when bupropion was coadministered with warfarin. Metabolic and Nutritional Glycosuria. Musculoskeletal Leg cramps, fever/rhabdomyolysis, and muscle weakness. Nervous System Abnormal coordination, depersonalization, emotional lability, hyperkinesia, hypertonia, hypesthesia, vertigo, amnesia, ataxia, derealization, abnormal electroencephalogram (EEG), aggression, akinesia, aphasia, coma, dysarthria, dyskinesia, dystonia, euphoria, extrapyramidal syndrome, hypokinesia, increased libido, neuralgia, neuropathy, paranoid ideation, restlessness, suicide attempt, and unmasking tardive dyskinesia. Respiratory Bronchospasm and pneumonia. Skin Maculopapular rash, alopecia, angioedema, exfoliative dermatitis, and hirsutism. Special Senses Accommodation abnormality, dry eye, deafness, increased intraocular pressure, angle-closure glaucoma, and mydriasis. Urogenital Impotence, polyuria, prostate disorder, abnormal ejaculation, cystitis, dyspareunia, dysuria, gynecomastia, menopause, painful erection, salpingitis, urinary incontinence, urinary retention, and vaginitis.
Advertencias y Precauciones
5. WARNINGS AND PRECAUTIONS • 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 extended-release tablets (XL) 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 (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 4400 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 1000 patients treated) are provided in Table 1. Table 1Risk Differences in the Number of Suicidality Cases by Age Group in thePooled Placebo-Controlled Trials of Antidepressants in Pediatric and Adult Patients Age Range Drug-Placebo Difference in Number of Cases of Suicidality per 1000 Patients Treated Increases Compared to Placebo < 18 years 14 additional cases 18 to 24 years 5 additional cases Age Range Drug-Placebo Difference in Number of Cases of Suicidality per 1000 Patients Treated 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 and 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 health care providers. Such monitoring should include daily observation by families and caregivers. Prescriptions for bupropion hydrochloride extended-release tablets (XL) 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 Symptoms and Suicide Risk in Smoking Cessation Treatment Bupropion hydrochloride extended-release tablets (XL) are not approved for smoking cessation treatment; however, bupropion hydrochloride sustained-release is approved for this use. Serious neuropsychiatric symptoms have been reported in patients taking bupropion for smoking cessation. These have included changes in mood (including depression and mania), psychosis, hallucinations, paranoia, delusions, homicidal ideation, hostility, agitation, aggression, anxiety, and panic, as well as suicidal ideation, suicide attempt, and completed suicide [see Boxed Warning and Adverse Reactions ( 6.2 ) ]. Observe patients for the occurrence of neuropsychiatric reactions. Instruct patients to contact a healthcare professional if such reactions occur. In many of these cases, a causal relationship to bupropion treatment is not certain, because depressed mood can be a symptom of nicotine withdrawal. However, some of the cases occurred in patients taking bupropion who continued to smoke. 5.3 Seizure Bupropion hydrochloride extended-release tablets (XL) can cause seizure. The risk of seizure is dose-related. The dose should not exceed 300 mg once daily. Increase the dose gradually. Discontinue bupropion hydrochloride extended-release tablets (XL) 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 extended-release tablets (XL). Bupropion hydrochloride extended-release tablets (XL) is contraindicated in patients with a seizure disorder or conditions that increase the risk of seizure (e.g., severe head injury, arteriovenous malformation, CNS tumor or CNS infection, severe stroke, anorexia nervosa or bulimia, or abrupt discontinuation of alcohol, benzodiazepines, barbiturates, and antiepileptic drugs [see Contraindications ( 4 ) ]. The following conditions can also increase the risk of seizure: 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), or 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, excessive use of alcohol, benzodiazepines, sedative/hypnotics, or opiates. Incidence of Seizure with Bupropion Use The incidence of seizure with bupropion hydrochloride extended-release tablets (XL) has not been formally evaluated in clinical trials. In studies using bupropion hydrochloride sustained-release up to 300 mg per day the incidence of seizure was approximately 0.1% (1/1000 patients). In a large prospective, follow-up study, the seizure incidence was approximately 0.4% (13/3200) with bupropion hydrochloride immediate-release in the range of 300 mg to 450 mg per day. Additional data accumulated for bupropion immediate-release suggests that the estimated seizure incidence increases almost tenfold between 450 and 600 mg/day. The risk of seizure can be reduced if the bupropion hydrochloride extended-release tablets (XL) dose does not exceed 450 mg once daily and the titration rate is gradual. 5.4 Hypertension Treatment with bupropion hydrochloride extended-release tablets (XL) can result in elevated blood pressure and hypertension. Assess blood pressure before initiating treatment with bupropion hydrochloride extended-release tablets (XL), and monitor periodically during treatment. The risk of hypertension is increased if bupropion hydrochloride extended-release tablets (XL) 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 hydrochloride, 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 to 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 preexisting 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 the 3 trials of bupropion hydrochloride extended-release in seasonal affective disorder, there were significant elevations in blood pressure. Hypertension was reported as an adverse reaction for 2% of the bupropion group (11/537) and none in the placebo group (0/511). In the SAD trials, 2 patients treated with bupropion discontinued from the study because they developed hypertension. None of the placebo group discontinued because of hypertension. The mean increase in systolic blood pressure was 1.3 mmHg in the bupropion group and 0.1 mmHg in the placebo group. The difference was statistically significant (p=0.013). The mean increase in diastolic blood pressure was 0.8 mmHg in the bupropion group and 0.1 mmHg in the placebo group. The difference was not statistically significant (p=0.075). In the SAD trials, 82% of patients were treated with 300 mg per day, and 18% were treated with 150 mg per day. The mean daily dose was 270 mg per day. The mean duration of bupropion exposure was 126 days. 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 preexisting hypertension in 2 patients, leading to discontinuation of bupropion treatment. There are no controlled studies 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 extended-release tablets (XL), 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 extended-release tablets (XL) are not approved for the treatment of bipolar depression. 5.6 Psychosis and Other Neuropsychiatric Reactions Depressed patients treated with bupropion 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. Discontinue bupropion hydrochloride extended-release tablets (XL) if these reactions occur. 5.7 Angle-Closure Glaucoma Angle-Closure Glaucoma: The pupillary dilation that occurs following use of many antidepressant drugs including bupropion hydrochloride extended-release tablets (XL) 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 extended-release tablets (XL) and consult a health care 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 symptoms of serum sickness suggestive of delayed hypersensitivity.
Contraindicaciones
4. CONTRAINDICATIONS • 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 extended-release tablets (XL) or within 14 days of stopping treatment with bupropion hydrochloride extended-release tablets (XL). Do not use bupropion hydrochloride extended-release tablets (XL) within 14 days of stopping an MAOI intended to treat psychiatric disorders. In addition, do not start bupropion hydrochloride extended-release tablets (XL) 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 ) • Bupropion hydrochloride extended-release tablets (XL) are contraindicated in patients with seizure disorder. • Bupropion hydrochloride extended-release tablets (XL) 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 extended-release tablets (XL) [see Warnings and Precautions ( 5.3 ) ] . • Bupropion hydrochloride extended-release tablets (XL) are contraindicated in patients undergoing abrupt discontinuation of alcohol, benzodiazepines, barbiturates, and antiepileptic drugs [see Warnings and Precautions ( 5.3 ) and Drug Interactions ( 7.3 ) ]. • The use of MAOIs (intended to treat psychiatric disorders) concomitantly with bupropion hydrochloride extended-release tablets (XL) or within 14 days of discontinuing treatment with bupropion hydrochloride extended-release tablets (XL) is contraindicated. There is an increased risk of hypertensive reactions when bupropion hydrochloride extended-release tablets (XL) are used concomitantly with MAOIs. The use of bupropion hydrochloride extended-release tablets (XL) within 14 days of discontinuing treatment with an MAOI is also contraindicated. Starting bupropion hydrochloride extended-release tablets (XL) 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 ) and Drug Interactions ( 7.6 ) ]. • Bupropion hydrochloride extended-release tablets (XL) are 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 ) ].
Farmacocinética
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 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 14 C-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 patients 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 extended-release tablets (XL) 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 ) and 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 (t1/2) 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 and about 2½ fold for threo/erythrohydrobupropion. The median T max was observed 19 hours later for hydroxybupropion and 31 hours later for threo/erythrohydrobupropion. The mean half-lives for hydroxybupropion and threo/erythrohydrobupropion were increased 5 and 2 fold, respectively, in patients with severe hepatic cirrhosis compared to healthy volunteers [see Dosage and Administration ( 2.6 ) and Use in Specific Populations ( 8.7 ) ]. Left Ventricular Dysfunction During a chronic dosing study with bupropion in 14 depressed patients 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 to 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 studies involving patients 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 study demonstrated that the disposition of bupropion and its metabolites in elderly subjects was similar to that in younger subjects. These data suggest that there is no prominent effect of age on bupropion concentration; however, another single-and multiple-dose pharmacokinetic study suggested that the elderly are at increased risk for accumulation of bupropion and its metabolites [see Use in Specific Populations ( 8.5 ) ]. Gender A single-dose study involving 12 healthy male and 12 healthy female volunteers, revealed no sex-related differences in the pharmacokinetic parameters of bupropion. In addition, 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 to female volunteers. Smokers The effects of cigarette smoking on the pharmacokinetics of bupropion hydrochloride 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 was no statistically significant difference in C max , half-life, T max , AUC, or clearance of bupropion or its active metabolites between smokers and nonsmokers. Drug Interactions Potential for Other Drugs to Affect Bupropion Hydrochloride Extended-release Tablets (XL) In vitro studies indicate that 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. 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 study 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, by 38% and 85% for ticlopidine, respectively. The exposures of hydroxybupropion were decreased. Prasugrel: 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, by 32% and 24%, respectively. Cimetidine: Following oral administration of bupropion 300 mg with and without cimetidine 800 mg in 24 healthy young male volunteers, 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 study, 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 study, ritonavir 600 mg twice daily decreased the AUC and 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 study, lopinavir 400 mg/ritonavir 100 mg twice daily decreased bupropion AUC and C max by 57%. The AUC and C max of hydroxybupropion metabolite were decreased by 50% and 31% , respectively. Efavirenz: In a study of 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 Extended-release Tablets (XL) to Affect Other Drugs Animal data indicated that bupropion may be an inducer of drug-metabolizing enzymes in humans. In a study of 8 healthy male volunteers, following a 14 day administration of bupropion 100 mg three times per day, there was no evidence of induction of its own metabolism. Nevertheless, there may be the potential for clinically important alterations of blood levels of coadministered drugs. Drugs Metabolized by CYP2D6 In vitro, bupropion and hydroxybupropion are CYP2D6 inhibitors. In a clinical study of 15 male subjects (ages 19 to 35 years) who were extensive metabolizers of CYP2D6, bupropion given as 150 mg twice daily followed by a single dose of 50 mg desipramine increased the C max , AUC, and T½ 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 study 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.