Therefore, the potential exists for a drug interaction between bupropion and drugs that are substrates or inhibitors of the CYP2B6 isoenzyme (e.g., orphenadrine, thiotepa, and cyclophosphamide).
Source: FDA drug label - bupropion hydrochloride
Bupropion Hydrochloride Interactions
Brand names: Bupropion Hydrochloride Sr
5 interactions on record
7 DRUG INTERACTIONS CYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, and phenytoin) based on clinical exposure, but should not exceed the maximum recommended dose. Inducers of CYP2B6 Ritonavir, Lopinavir, and Efavirenz: Concomitant treatment with these drugs can decrease bupropion and hydroxybupropion exposure. Dosage increase of bupropion hydrochloride extended-release tablets (XL) may be necessary when coadministered with ritonavir, lopinavir, or efavirenz but should not exceed the maximum recommended dose [see Clinical Pharmacology (12.3) ].
Source: FDA drug label - bupropion hydrochloride
( 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). 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).
Source: FDA drug label - bupropion hydrochloride
In addition, in vitro studies suggest that paroxetine, sertraline, norfluoxetine, and fluvoxamine as well as nelfinavir, ritonavir, and efavirenz inhibit the hydroxylation of bupropion.
Source: FDA drug label - bupropion hydrochloride
7 DRUG INTERACTIONS CYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, and phenytoin) based on clinical exposure, but should not exceed the maximum recommended dose. Inducers of CYP2B6 Ritonavir, Lopinavir, and Efavirenz: Concomitant treatment with these drugs can decrease bupropion and hydroxybupropion exposure. Dosage increase of bupropion hydrochloride extended-release tablets (XL) may be necessary when coadministered with ritonavir, lopinavir, or efavirenz but should not exceed the maximum recommended dose [see Clinical Pharmacology (12.3) ].
Source: FDA drug label - bupropion hydrochloride