From the FDA Drug Label
Drugs metabolized by CYP2D6: Bupropion inhibits CYP2D6 and can increase concentrations of: antidepressants (e.g., venlafaxine, nortriptyline, imipramine, desipramine, paroxetine, fluoxetine, sertraline),
- Key Interaction: Bupropion, a component of Contrave, inhibits CYP2D6, which can increase concentrations of venlafaxine (Effexor).
- Clinical Implication: Consider dose reduction of Effexor when using with Contrave, as increased concentrations of venlafaxine may occur 1.
- Precaution: Use Contrave with Effexor with caution and monitor for increased adverse effects of venlafaxine.
From the Research
Taking Contrave (bupropion and naltrexone) with Effexor (venlafaxine) is generally not recommended due to potential serious drug interactions, particularly the risk of serotonin syndrome, as highlighted in a case report from 2. These medications should not be combined without explicit medical supervision from a healthcare provider who is aware of your complete medication history. The main concern is that both Contrave and Effexor affect brain chemicals like serotonin and norepinephrine, and using them together increases the risk of serotonin syndrome, a potentially life-threatening condition characterized by agitation, hallucinations, rapid heart rate, fever, excessive sweating, shivering, muscle stiffness, twitching, loss of coordination, nausea, vomiting, and diarrhea. Additionally, bupropion (in Contrave) and venlafaxine (Effexor) can both lower the seizure threshold, potentially increasing seizure risk when taken together, as discussed in the context of pharmacodynamic interactions in 3. Some key points to consider include:
- The risk of serotonin syndrome with combined use of serotonergic agents, as illustrated by a case report in 2
- The potential for pharmacokinetic interactions due to the inhibition of cytochrome P450 enzymes by bupropion, as noted in 3
- The importance of careful medical supervision when combining these medications, to monitor for signs of serotonin syndrome or other adverse effects If you're currently taking one of these medications and considering the other, consult with your doctor about possible alternatives or whether the benefits might outweigh the risks in your specific situation, taking into account the latest clinical guidelines and evidence, such as the review of bupropion's effectiveness as an antidepressant in 4. Never adjust your medication regimen without professional medical guidance.