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Zyban vs. Chantix: Differences, similarities and which is better for you

Drug overview & main differences | Conditions treated | Efficacy | Insurance coverage and cost comparison | Side effects | Drug interactions | Warnings | FAQ

In July 2021, Pfizer paused production of Chantix and recalled the drug due to increased nitrosamine levels. The FDA later approved varenicline tartrate, the generic version, which is what is now widely available. Although people still use the term “Chantix,” the brand-name drug isn’t currently available.

The health benefits of quitting smoking are numerous. Lower blood pressure and heart rate comes almost immediately and the risk of heart attack decreases in as little as 24 hours. Furthermore, cholesterol will improve, cancer risk decreases and your immune system and bones will get stronger.

Sometimes you need extra help quitting, and prescription medication can help. Two of the most commonly prescribed medications for smoking cessation include Zyban (bupropion Hcl Er) and Chantix. Both medications are approved by the U.S. Food and Drug Administration (FDA) and are used to aid patients with smoking cessation, but they work in different ways and have different side effects.

What are the main differences between Zyban and Chantix?

Zyban (bupropion Hcl Er) is available in generic, as 150 mg extended-release tablets. Zyban is no longer available in brand name; it was originally made by GlaxoSmithKline. It is used in patients 14 and older; patients also must weigh at least 89 lbs. Zyban is started one week before the smoking quit date, and is taken for 7-12 weeks, on average.

Chantix (varenicline) is available in brand name only, as 0.5 mg and 1 mg tablets, and it is made by the drug company Pfizer. Chantix, which is used in adults only, is started one week before the smoking quit date and is taken for 12 weeks; patients may continue for another 12 weeks if the first cycle is successful.


Main differences between Zyban and Chantix
Zyban Chantix
Drug class Aminoketone antidepressant, smoking cessation aid Nicotinic agonist, smoking cessation aid
Brand/generic status Generic Brand
What is the generic name? Bupropion Varenicline
What form(s) does the drug come in? Extended-release tablet Tablets
What is the standard dosage? Start one week before smoking quit date: 150 mg daily for 3 days, then 150 mg twice daily (at least 8 hours apart) thereafter Start one week before smoking quit date: 0.5 mg daily for 3 days, then 0.5 mg twice daily for 4 days, then 1 mg twice daily thereafter
How long is the typical treatment? 7-12 weeks; varies 12 weeks, may continue another 12 weeks
Who typically uses the medication? Adults and adolescents 14 years of age and older, must be over 40.5 kg Adults 17 years of age and older

Conditions treated by Zyban and Chantix

Zyban (bupropion) and Chantix (varenicline) are both indicated as an aid to smoking cessation treatment. Neither drug contains nicotine.

Zyban is an aminoketone antidepressant; its exact mechanism in smoking cessation or depression is unknown but is presumed to inhibit the uptake of norepinephrine and dopamine. By doing so, nicotine cravings decrease and withdrawal symptoms are lessened.

Not to be confused with Wellbutrin, which also contains bupropion, Zyban is only used for smoking cessation while the Wellbutrin form of bupropion is used for Major Depressive Disorder and Seasonal Affective Disorder. The two drugs are not interchangeable. However, some doctors do prescribe Wellbutrin off-label for smoking cessation.

Chantix works by blocking nicotine receptors. By doing so, the central nervous system will not activate the reinforcement/reward system associated with nicotine, and you will feel less mental and physical pleasure from smoking. Chantix also lessens the symptoms of smoking withdrawal.

Condition Zyban Chantix
Smoking cessation Yes Yes

Is Zyban or Chantix more effective?

The safety and efficacy of Zyban was studied in several trials, using Zyban along with counseling. In a seven-week study, Zyban was shown to be significantly more effective than placebo. At six months, patients did better at maintaining abstinence after having been treated with Zyban. In another study, treatment with Zyban was also significantly more effective than placebo, reducing the urge to smoke, and reducing withdrawal symptoms (such as irritability, anger, and anxiety).

In clinical trials of Chantix, the drug was found to reduce the urge to smoke, reduce withdrawal symptoms, and help patients maintain abstinence. One study compared Chantix to Zyban to placebo. The study found that both drugs were better than placebo, and concluded that Chantix was more effective than Zyban.

The most effective medication should only be determined by your doctor, taking into account your medical condition(s), history, and other medications you are taking that could interact with Zyban or Chantix.

Coverage and cost comparison of Zyban vs. Chantix

Zyban generics are typically covered by insurance as well as Medicare Part D. Without insurance, a one-month supply of generic Zyban costs about $90. You can lower this price to $50-80 with a SingleCare coupon depending on your local pharmacy.

With Chantix, you’ll begin with a lower dose (the starting month pack), and then go on to fill the continuing month pack the second and third month. Chantix is often covered by insurance and Medicare Part D, with variable copays. Without insurance, a starting month pack costs approximately $515 and the continuing month pack costs approximately $500. You can reduce the price of Chantix products with a SingleCare coupon.

Zyban Chantix
Typically covered by insurance? Yes (generic) Usually; may require prior authorization and/or have a high copay
Typically covered by Medicare Part D? Yes (generic) Usually; copays vary greatly
Standard dosage 150 mg daily for 3 days then 150 mg twice daily 0.5 mg daily for 3 days, then 0.5 mg twice daily for 4 days, then 1 mg twice daily (starting pack is used month one, then continuing pack is used)
Typical Medicare Part D copay Average $3-64; varies $25-578; varies
SingleCare cost $58 $400 for starting pack, $452 for continuing pack

Common side effects of Zyban and Chantix

In addition to the serious side effects/warnings, which are described below, each drug comes with possible adverse effects. Zyban is often prescribed along with a nicotine patch (also known as nicotine replacement therapy, or NRT), and side effect percentages can be higher when Zyban is used in combination with nicotine.

The most common side effects of Zyban are insomnia, dry mouth, and dizziness. The most common adverse effects of Chantix are nausea, abdominal pain, headache, and insomnia.

A medication guide, with detailed information about the medication, will be given to you with a new or refill prescription of Zyban or Chantix. Consult your healthcare provider for a complete list of side effects.

Side effect Zyban: applicable? Zyban: percent Chantix: applicable? Chantix: percent
Nausea Yes 9% Yes 30%
Stomach pain Yes 3% Yes 7%
Insomnia/trouble sleeping Yes 40% Yes 18%
Abnormal dreams Yes 5% Yes 13%
Headache No Yes 15%
Fatigue Rare % not given Yes 7%
Dizziness Yes 10% Yes “Frequent”: % not given
Dry mouth Yes 10% Yes 6%

Sources: DailyMed (Chantix) and DailyMed (Zyban)

Drug interactions of Zyban vs. Chantix

Zyban has a significant amount of drug interactions, detailed in the chart below. Many of the drug interactions are due to enzymes called CYP2B6 and CYP2D6. Some examples are seizure medications as well as Digoxin, a heart medication. Alcohol should be avoided while on Zyban.

Based on the characteristics of the drug, Chantix has no significant drug interactions. Chantix has not been studied for safety in combination with Zyban. When Chantix was studied in combination with nicotine replacement therapy, the incidence of side effects such as nausea, headache, vomiting, dizziness, indigestion, and fatigue, was much higher than with nicotine alone.

Chantix should not be used in combination with alcohol, at least until you know how Chantix affects your ability to tolerate alcohol. Consult your healthcare provider for more information.

Drug(s) Drug class Zyban Chantix
Nicotine Nicotine replacement therapy No Yes
Tegretol (carbamazepine), Neurontin (gabapentin), Lamictal (lamotrigine), Phenobarbital, Dilantin (phenytoin), Trileptal (oxcarbazepine), Topamax (topiramate), Depakote (divalproex sodium) Seizure medications, some are also used for bipolar disorder Yes No
Klonopin (clonazepam), Valium (diazepam), Ativan (lorazepam) Benzodiazepines Yes No
Plavix (clopidogrel) Antiplatelet Yes No
Alcohol Alcohol Yes Yes
Lanoxin (digoxin) Cardiac glycoside Yes No
Lopressor or Toprol XL (metoprolol), Tenormin (atenolol), Inderal (propranolol) Beta-blockers Yes No
Risperdal (risperidone), Haldol (haloperidol) Antipsychotics Yes No
Effexor (venlafaxine), Pamelor (nortriptyline), Paxil (paroxetine), Prozac (fluoxetine), Zoloft (sertraline) Antidepressants Yes No
Ultram (tramadol), Codeine Painkillers Yes No
Eldepryl (selegiline), Parnate (tranylcypromine) MAO Inhibitors Yes No

The list of drug interactions for Zyban is too long to list here; consult your healthcare provider for more information.

Warnings of Zyban and Chantix

Zyban warnings:

Zyban comes with a black box warning (the strongest warning as required by the FDA, indicating a risk of serious or life-threatening events) of suicidality. Zyban contains bupropion, an antidepressant, and antidepressants may increase the risk of suicidal thoughts and behavior in patients 24 years of age and younger. Patients and their caregivers should be aware of any mood changes, hallucinations, paranoia, delusions, homicidal ideation, aggression, hostility, agitation, anxiety, and panic. Any patient taking Zyban, regardless of age, should be closely monitored. Here are more warnings:

  • Risk of mania or psychosis; the risk can be higher in patients with bipolar disorder.
  • Zyban can cause seizures; the risk is dose-related. The dose should not exceed 300 mg per day. Other medical conditions can increase the risk of seizures.
  • Zyban may cause high blood pressure; monitor blood pressure while taking Zyban.
  • Certain patients may be at risk for glaucoma; consult your ophthalmologist for more information.
  • Serious, potentially life-threatening skin reactions (Stevens-Johnson syndrome) may occur; contact your healthcare provider immediately if you develop a skin rash.

Zyban should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. Pregnant smokers should be encouraged to stop smoking through behavioral techniques before using Zyban. The Zyban package insert states that because of the risk to the baby, nursing mothers should either stop breastfeeding or stop Zyban. Consult your healthcare provider for advice.

Chantix warnings:

Chantix comes with a boxed warning of serious neuropsychiatric events. Depression, suicidal ideation, suicide attempt, and completed suicide have been reported in patients taking Chantix. You should stop taking Chantix and contact your healthcare provider immediately if you develop agitation, hostility, depressed mood, or changes in behavior or thinking that are not typical, or if you experience suicidal thoughts.  Here are more warnings associated with Chantix:

  • Risk of hypersensitivity or angioedema, which is swelling of the face, mouth, (tongue, lips, and gums), extremities, and neck. Stop Chantix and seek emergency medical care if this occurs.
  • As with Zyban, Stevens-Johnson syndrome could occur. Contact your healthcare provider immediately if you develop a skin rash.
  • Possible increased chance of cardiovascular events; notify your healthcare provider of new or worsening symptoms of cardiovascular disease.
  • Use caution driving or operating machinery until you know how Chantix affects you; accidental injuries have occurred due to sleepiness or dizziness.

Pregnant mothers beware of Chantix’s effects on the fetus. As with Zyban, pregnant smokers should be encouraged to stop smoking through behavioral techniques. The Chantix package insert states that because of the risk to the baby, nursing mothers should either stop breastfeeding or stop Chantix.

Patients on Chantix should be closely monitored.

In 2016, the FDA reported that the risk of serious mental health side effects from Zyban and Chantix may be lower than previously thought and that the benefits of smoking cessation outweigh the risks of using these medications. Regardless, the drug information still contains the same warnings and patients should be closely monitored while on Zyban or Chantix.

Frequently asked questions about Zyban vs. Chantix

What is Zyban?

Zyban (bupropion) is a medication used as an aid in the treatment of smoking cessation.

What is Chantix?

Chantix (varenicline) is a medication used as an aid in the treatment of smoking cessation.

Are Zyban and Chantix the same?

No. Both drugs work in different ways to aid in the treatment of smoking cessation. Zyban’s exact mechanism is not known but is presumed to be related to dopamine and norepinephrine. Chantix works by blocking nicotine receptors, and by blocking the reinforcement and reward sensation in the central nervous system. Neither drug contains nicotine. They also have different costs, drug interactions, side effects, and warnings, as detailed above.

Is Zyban or Chantix better?

Everyone reacts differently to different medications. Only your doctor can determine which medication is best for you, taking into account your medical history, medical condition(s), and other medications you are taking.

Is there an alternative to Chantix?

There is currently no generic alternative to Chantix.

Does Chantix help to stop smoking?

Yes. Chantix can help reduce your urge to smoke and help with withdrawal symptoms.