Bupropion hydrobromide

7 DRUG INTERACTIONS • CYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, phenytoin) based on clinical exposure, but should not exceed the maximum dose. ( 7.1 ) • Drugs metabolized by CYP2D6: Bupropion inhibits CYP2D6 and can increase concentrations of: antidepressants (e.g., venlafaxine, nortriptyline, imipramine, desipramine, paroxetine, fluoxetine, sertraline), antipsychotics (e.g., haloperidol, risperidone, thioridazine), beta-blockers (e.g., metoprolol), and Type 1C antiarrhythmics (e.g., propafenone, flecainide). Consider dose reduction when using with bupropion.

( 7.2 ) • Drugs that lower seizure threshold: Dose bupropion hydrobromide extended-release tablets with caution. ( 5.3 , 7.3 ) • Dopaminergic Drugs (levodopa and amantadine): CNS toxicity can occur when used concomitantly with bupropion hydrobromide extended-release tablets. ( 7.4 ) • MAOIs: Increased risk of hypertensive reactions can occur when used concomitantly with bupropion hydrobromide extended-release tablets. ( 7.6 ) • Drug-laboratory test interactions: Bupropion Hydrobromide Extended-Release Tablets can cause false-positive urine test results for amphetamines. ( 7.7 )

7.1 Potential for Other Drugs to Affect Bupropion Hydrobromide Extended-Release Tablets Bupropion is primarily metabolized to hydroxybupropion by CYP2B6. Therefore, the potential exists for drug interactions between bupropion hydrobromide extended-release tablets and drugs that are inhibitors or inducers of CYP2B6. Inhibitors of CYP2B6 Ticlopidine and Clopidogrel: Concomitant treatment with these drugs can increase bupropion exposures but decrease hydroxybupropion exposure.

Based on clinical response, dosage adjustment of bupropion hydrobromide extended-release 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 hydrobromide extended-release tablets may be necessary when coadministered with ritonavir, lopinavir, or efavirenz but should not exceed the maximum recommended dose [see Clinical Pharmacology (12.3) ].

Carbamazepine, Phenobarbital, Phenytoin: While not systemically studied, these drugs may induce metabolism of bupropion and may decrease bupropion exposure [see Clinical Pharmacology (12.3) ] . If bupropion is used concomitantly with a CYP inducer, it may be necessary to increase the dose of bupropion, but the maximum recommended dose should not be exceeded.

7.2 Potential for Bupropion Hydrobromide Extended-Release Tablets to Affect Other Drugs Drugs Metabolized by CYP2D6 Bupropion and its metabolites (erythrohydrobupropion, threohydrobupropion, hydroxybupropion) are CYP2D6 inhibitors. Therefore, coadministration of bupropion hydrobromide extended-release 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, and thioridazine), beta-blockers (e.g., metoprolol), and Type 1C antiarrhythmics (e.g., propafenone, and flecainide). When used concomitantly with bupropion hydrobromide extended-release 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 hydrobromide extended-release tablets and such drugs may require increased doses of the drug [see Clinical Pharmacology (12.3) ].

7.3 Drugs That Lower Seizure Threshold Use extreme caution when coadministering bupropion hydrobromide extended-release tablets with other drugs that lower the seizure threshold (e.g., other bupropion products, antipsychotics, antidepressants, theophylline, or systemic corticosteroids). Use low initial doses of bupropion hydrobromide extended-release tablets and increase the dose gradually [see Warnings and Precautions (5.3) ].

7.4 Dopaminergic Drugs (Levodopa and Amantadine) Bupropion, levodopa, and amantadine have dopamine agonist effects. CNS toxicity has been reported when bupropion was coadministered with levodopa or amantadine. Adverse reactions have included restlessness, agitation, tremor, ataxia, gait disturbance, vertigo, and dizziness. It is presumed that the toxicity results from cumulative dopamine agonist effects. Use caution when administering bupropion hydrobromide extended-release 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 hydrobromide extended-release tablets. The consumption of alcohol during treatment with bupropion hydrobromide extended-release 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 hydrobromide extended-release tablets.

Conversely, at least 14 days should be allowed after stopping bupropion hydrobromide extended-release tablets before starting an MAOI antidepressant [see Dosage and Administration (2.8 , 2.9 ) and 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.

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antidepressants during pregnancy. Healthcare providers are encouraged to register patients by calling the National Pregnancy Registry for Antidepressants at 1-844-405-6185 or visiting online at https://womensmentalhealth.org/clinical-and-research-programs/pregnancyregistry/antidepressants/. Risk Summary Data from epidemiological studies of pregnant women exposed to bupropion in the first trimester have not identified an increased risk of congenital malformations overall ( see Data) .

There are risks to the mother associated with untreated depression (see Clinical Considerations) . When bupropion was administered to pregnant rats during organogenesis, there was no evidence of fetal malformations at doses up to approximately 10 times the maximum recommended human dose (MRHD) of 450 mg/day. When given to pregnant rabbits during organogenesis, non-dose-related increases in incidence of fetal malformations and skeletal variations were observed at doses approximately equal to the MRHD and greater. Decreased fetal weights were seen at doses twice the MRHD and greater (see Data) .

The estimated background risk for major birth defects and miscarriage are unknown for the indicated population. All pregnancies have a background rate of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Disease-associated maternal and/or embryo/fetal risk A prospective, longitudinal study followed 201 pregnant women with a history of major depressive disorder who were euthymic and taking antidepressants during pregnancy at the beginning of pregnancy.

The women who discontinued antidepressants during pregnancy were more likely to experience a relapse of major depression than women who continued antidepressants. Consider the risks to the mother of untreated depression and potential effects on the fetus when discontinuing or changing treatment with antidepressant medications during pregnancy and postpartum. Data Human Data Data from the international bupropion Pregnancy Registry (675 first trimester exposures) and a retrospective cohort study using the United Healthcare database (1,213 first trimester exposures) did not show an increased risk for malformations overall.

The Registry was not designed or powered to evaluate specific defects but suggested a…