What is the interaction between Varenicline (Champix) and Bupropion (Wellbutrin)?

From the Guidelines

Champix (varenicline) and Wellbutrin (bupropion) can be considered for smoking cessation, with Champix being a preferred first-line option due to its higher efficacy, as shown in a study published in 2007 1. When deciding between these medications, it's essential to consider their mechanisms of action and potential side effects. Champix works by partially activating nicotine receptors to reduce cravings and withdrawal symptoms while blocking the pleasurable effects of smoking. Wellbutrin, an antidepressant, reduces nicotine cravings by affecting dopamine and norepinephrine levels in the brain.

Key Considerations

• Standard dosing for Champix involves a one-week titration (0.5mg once daily for days 1-3, then 0.5mg twice daily for days 4-7), followed by 1mg twice daily for 11 weeks, as recommended in the 2016 guidelines 1.
• Wellbutrin SR is typically started at 150mg once daily for 3 days, then increased to 150mg twice daily for 7-12 weeks.
• Patients should set a quit date, usually during the second week of treatment.
• Common side effects include nausea, sleep disturbances, headache, and dry mouth, with nausea being the most common adverse effect attributed to varenicline, occurring in approximately one-third of treated patients 1.
• Both medications require prescription and medical supervision, especially since they may interact with other medications and can cause psychiatric symptoms in some individuals.
• Patients with kidney problems, seizure disorders, or eating disorders require special consideration before using these medications, as varenicline is contraindicated for patients with brain metastases due to seizure risk, and bupropion is contraindicated for patients with seizure risks or those taking MAO inhibitors 1.

Special Considerations

• For patients who have failed monotherapy, some healthcare providers may consider combination therapy with Champix and Wellbutrin, though this combination is not routinely recommended as first-line therapy.
• The benefits of smoking cessation have been extensively reported, with stopping smoking after an MI being potentially the most effective of all preventive measures, as stated in the 2007 European guidelines on cardiovascular disease prevention in clinical practice 1.

From the FDA Drug Label

1. 1 Use with Other Drugs for Smoking Cessation Safety and efficacy of varenicline in combination with other smoking cessation therapies have not been studied. Bupropion Varenicline (1 mg twice daily) did not alter the steady-state pharmacokinetics of bupropion (150 mg twice daily) in 46 smokers. The safety of the combination of bupropion and varenicline has not been established

• Key Points:
  • Varenicline (Champix) and bupropion (Wellbutrin) have been studied together in terms of pharmacokinetics.
  • The study found that varenicline did not alter the steady-state pharmacokinetics of bupropion.
  • However, the safety of the combination of bupropion and varenicline has not been established 2.
  • It is not recommended to use varenicline and bupropion together without consulting a healthcare professional.

From the Research

Overview of Champix and Wellbutrin

• Champix, also known as varenicline, is a partial agonist at nicotinic alpha4beta2 receptors, used as an aid to smoking cessation therapy 3.
• Wellbutrin, also known as bupropion, is an inhibitor of the neuronal uptake of noradrenaline and dopamine, used for smoking cessation and as an atypical antidepressant 4, 5.

Efficacy of Champix and Wellbutrin

• Varenicline has been shown to be effective in smoking cessation, with higher continuous abstinence rates compared to placebo or bupropion sustained-release (SR) 3.
• Bupropion is also effective for smoking cessation, and its effectiveness is improved by a moderate level of counselling 4.
• Combination therapy of varenicline and bupropion has been shown to be more effective than varenicline monotherapy in some studies 6.

Comparison of Champix and Wellbutrin

• Varenicline seems to be more effective in maintaining abstinence and reducing craving than bupropion and nicotine replacement therapy (NRT) 5.
• Bupropion is generally well tolerated, but can have adverse effects such as nausea, insomnia, anxiety, irritability, fatigue, and abnormal dreams 5.
• Varenicline is also generally well tolerated, but can have adverse effects such as nausea, insomnia, and abnormal dreams 3.

Safety and Tolerability

• Both varenicline and bupropion are considered safe and effective treatments for smoking cessation, but can have adverse effects 3, 5.
• The safety and tolerability of combination therapy of varenicline and bupropion need to be further studied to rule out additive psychiatric adverse effects 6.