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Zyban (Bupropion) vs. Chantix (Varenicline): Which is Best?

Katelyn Hagerty FNP

Medically reviewed by Kristin Hall, FNP

Written by Our Editorial Team

Last updated 8/09/2020

From lung cancer to heart disease, the negative health effects of smoking are numerous and well known. Add the incredible lifetime cost of nicotine addiction into the equation and it’s no wonder seven out of every 10 adult smokers want to quit completely

If you’re in the process of quitting smoking, or are considering quitting, you may be aware that there are medications available that can make the process easier. 

Bupropion (the active ingredient in Zyban® and Wellbutrin®) and varenicline (the active ingredient in Chantix®) are two of the most well-known, effective medications available for helping you quit smoking.

Used properly, both of these drugs can reduce your cravings for nicotine and make the process of quitting easier. However, there are a few key differences between these medications that you should be aware of if you’re considering using either to quit smoking. 

Below, we’ve explained how bupropion and varenicline work to help you treat your addiction to nicotine and quit smoking. We’ve also looked at some of the biggest differences between these two medications, from effectiveness to side effects, interactions and more.

Zyban (Bupropion) and Chantix (Varenicline): An Overview

Zyban, which contains bupropion, and Chantix, which contains varenicline, are two medications approved by the FDA as smoking cessation aids. Neither medication contains nicotine. 

Research shows that both drugs are effective at reducing cravings and making it easier to stop smoking. 

Of the two medications, Zyban is the oldest. It contains the active ingredient bupropion, which has been used since the 1980s to treat depression. In 1997, the FDA approved bupropion for use as a smoking cessation medication.

Zyban, or generic bupropion, is a prescription medication, meaning you’ll need to talk to your healthcare provider before you can purchase and use it. It comes in tablet form and is intended for use as one single dose or two separate doses per day. 

Chantix is a slightly newer medication. It was approved in 2006 by the FDA. Unlike bupropion, which is also used to treat depression, varenicline, the active ingredient in Chantix, is designed only for use as a smoking cessation treatment.

Like Zyban, Chantix is only available on prescription. It also comes in tablet form and is usually prescribed for use in one or two doses per day. 

Zyban and Chantix are both suitable for male or female smokers. Prescription guidelines tend to recommend the use of smoking cessation medication if you smoke more than 10 cigarettes per day, or if you’ve tried to quit before but started smoking again. 

Zyban (bupropion) and Chantix (varenicline) are both designed for daily use over the course of 12 weeks. It’s best to start using either medication slightly before you quit smoking. This allows the medication to build up in your bloodstream before you stop using nicotine. 

Is Either Medication Generic?

Right now, only Zyban is available as a generic drug. We offer generic bupropion (the active ingredient in Zyban) for use as a smoking cessation aid, available after an online consultation with a healthcare professional who will determine if a prescription is appropriate.

Chantix (varenicline) is not available as a generic medication. Because of this, it’s significantly more expensive than generic bupropion.

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How Zyban (Bupropion) and Chantix (Varenicline) Work

Medications like bupropion (the active ingredient in Zyban) and varenicline (the active ingredient in Chantix) are both designed to make you feel less dependent on nicotine.

Nicotine is a highly addictive chemical found in tobacco. Part of its incredible addictiveness is a result of its pharmacokinetic properties. When you smoke a cigarette, your body rapidly takes in nicotine via the lungs, with nicotine levels peaking in as little as 10 seconds

When it’s absorbed by your brain, nicotine works quickly to raise levels of the neurotransmitter dopamine — a chemical that’s used by your brain to manage feelings such as pleasure, reward, stress response and happiness.

Unfortunately, nicotine’s effects are short lived, which is why if you’re a regular smoker, you’ll often start craving another cigarette shortly after finishing the last one.

Over time, your body becomes both physically and psychologically addicted to the nicotine in cigarettes. 

When you stop smoking, you’ll often start to experience withdrawal symptoms such as strong, persistent cravings for nicotine, anxiety, depression, difficulty staying focused, insomnia and a stronger appetite. 

Nicotine withdrawal can be uncomfortable and unpleasant. Most of the time, the most difficult symptoms of nicotine withdrawal last for a few days to a few weeks. While this may not seem like a long time, making it through even a few days of withdrawal can be very difficult.

Smoking cessation medications like bupropion and varenicline work by changing the way your body deals with nicotine, reducing the severity of withdrawal symptoms and making it easier to stay away from cigarettes after you decide to quit. 

How Zyban (Bupropion) Works

Bupropion, the active ingredient in Zyban, works by increasing the level of the neurotransmitters dopamine and noradrenaline in your brain.

Dopamine and noradrenaline both play important roles in regulating your mood and overall state of mind. 

As we explained above, dopamine is responsible for regulating feelings such as happiness and pleasure. Norepinephrine, on the other hand, is responsible for keeping you alert, ensuring you can concentrate on specific tasks and supplying a consistent flow of blood to your heart. 

Research shows that when you smoke, the nicotine in each cigarette triggers a sudden spike in your body’s production of dopamine and norepinephrine

This is why you might feel more alert, mentally focused and prepared for certain tasks after you smoke.

When you quit, your body’s production of dopamine and norepinephrine drops. It can take up to three months after quitting for your production of dopamine to return to its normal, pre-smoking level. 

By increasing the amount of dopamine and noradrenaline that’s active in your brain, Zyban can make the withdrawal symptoms you feel after quitting smoking less severe, helping you to keep temptations at bay during the most difficult period of quitting. 

Bupropion, the active ingredient in Zyban, is also an antidepressant, meaning it may also help you to reduce the symptoms of post-quitting depression that many people experience. 

How Chantix (Varenicline) Works

Like Zyban, Chantix is designed to help you quit smoking. However, the mechanism by which it works in the body is slightly different.

Rather than changing the levels of certain neurotransmitters in your brain, varenicline works by targeting and activating receptors in your brain referred to as nicotinic acetylcholine receptors, or nAChRs. 

These are the same receptors that are affected by nicotine. People who use varenicline tend to experience nicotine-like effects after taking the medication, which can help to deal with nicotine withdrawal symptoms.

Varenicline also stops the nicotine in cigarettes from binding to these receptors, meaning you’ll feel less satisfaction and a weaker improvement in mood if you decide to smoke.

Which Medication is More Effective?

Studies show that Zyban and Chantix are both effective at helping people quit smoking. If you currently smoke and want to quit, you should find the quitting process easier if you use either type of medication. 

In a 1997 study, researchers found that smokers who took 150 or 300mg of bupropion per day were significantly more likely to successfully quit than those who used a placebo. 

After seven weeks of treatment, more than 44 percent of the people who used bupropion at a 300mg daily dose successfully stopped smoking. After one year, 23 percent had successfully quit — almost twice as many people as in the group given a non-therapeutic placebo. 

A large-scale review of studies of bupropion for smoking cessation from 2014 also noted that use of bupropion “significantly increased long-term cessation” among former smokers. 

Likewise, there’s a large amount of scientific research showing that Chantix is effective as a smoking cessation aid. 

In a detailed clinical review from 2016, researchers stated that clinical trials have found that varenicline is a “safe and effective agent” for smoking cessation. A separate study, also from 2016, found that varenicline doubled the quit rate of adult smokers. 

In short, if you smoke and want to quit, Zyban (bupropion) and Chantix (varenicline) will both increase your likelihood of success. 

Now, is one medication more effective than the other? Some studies have found that people who use Chantix (varenicline) have an ever-so-slightly higher rate of smoking cessation than smokers who use Zyban (bupropion). 

However, the difference is tiny (in one study, 20.5 percent vs. 18.6 percent). 

In short, both medications work well as smoking cessation aids, and using either one will significantly increase your chances of successfully giving up smoking compared to simply quitting cold turkey.

Side Effects and Interactions: Zyban (Bupropion) vs. Chantix (Varenicline)

Zyban (bupropion) and Chantix (varenicline) can both cause side effects. Side effects can differ between the two medications, and certain side effects common to both drugs may occur more frequently with one than the other.

The most common side effects of Zyban (bupropion) are dizziness, dry mouth, sleep difficulties and nausea. Zyban (bupropion) can also cause other side effects, including several potentially serious side effects, which we’ve listed in our full guide to bupropion

The most common side effects of Chantix (varenicline) are abdominal pain, nausea, difficulties sleeping and headache. Chantix (varenicline) may also cause certain serious side effects, including serious neuropsychiatric events such as depression and suicidal ideation. 

If you’re worried about side effects from either medication, it’s best to talk to your healthcare provider for more information. 

Zyban (bupropion) and Chantix (varenicline) can both interact with other medications. However, there are significantly more drug interactions that can occur with Zyban (bupropion). Our guide to bupropion lists these drug interactions and provides more information. 

Some interactions between bupropion and other medications can be dangerous, particularly if you currently use or have recently used certain antidepressants. 

If you’re considering either medication, inform your healthcare provider of all medications you currently use or have recently used (both over-the-counter and prescription) to ensure there are no harmful drug combinations. 

Zyban (bupropion) and Chantix (varenicline) are both often used alongside nicotine replacement therapy (NRT). If you use either type of medication with nicotine, you may have a higher risk of experiencing side effects and/or interactions. 

In Conclusion

If you want to stop smoking, medications like Zyban (bupropion) and Chantix (varenicline) can both make the process of quitting easier. Research shows that both medications work well as smoking cessation aids, especially when used with nicotine replacement therapy (NRT). 

Currently, bupropion is available as a generic medication, meaning it may be a more affordable choice than Chantix if your insurance plan doesn’t cover smoking cessation aids.

Research shows that smokers who quit using medication are more likely to remain smoke-free after quitting. Since both Zyban (bupropion) and Chantix (varenicline) are safe to use with NRT, you can use them alongside nicotine gum, patches or lozenges to make things easier. 

Ready to quit? Talk to a healthcare professional about using generic bupropion to successfully stop smoking, or learn more about how bupropion works in our detailed guide. 

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

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