Varenicline (Chantix) for Quitting Smoking

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Generic Name Brand Name
varenicline Chantix

How It Works

Varenicline is a pill you take that acts on sites in the brain affected by nicotine. Like nicotine medicines, varenicline helps with craving and withdrawal symptoms . But it also blocks the effects of nicotine from tobacco. If you start smoking again while taking varenicline, the medicine lowers the sense of satisfaction you get from smoking, improving the chances that you will quit.

Varenicline does not contain nicotine and does not help you quit smoking in the same way that nicotine replacement therapy does.

You start taking varenicline about a week before you quit smoking, and you take it for a total of 12 to 24 weeks.

Why It Is Used

Doctors prescribe varenicline to help adults quit smoking. It is not available as an over-the-counter medicine.

Varenicline has not been studied in children under age 18 and is not recommended to help them quit smoking.

How Well It Works

Varenicline doubles or triples the chances of quitting smoking. footnote 1 And it may work better than other medicines for quitting smoking.

Side Effects

Some of the common side effects include:

  • Nausea and, in rare cases, vomiting.
  • Vivid, strange, or unusual dreams.
  • Constipation.
  • Feeling sleepy.

Chantix may be linked with a small increase in risk for heart problems (including heart attack). Call your doctor if you have cardiovascular disease symptoms that are new or getting worse, such as chest pain or pressure, shortness of breath, calf pain when walking, or sudden onset of weakness, numbness, or difficulty speaking.

Stop taking this medicine and call your doctor right away if you or someone around you notices that you:

  • Feel anxious or nervous.
  • Feel upset, tense, or edgy.
  • Feel depressed or angry.
  • Feel different, with unusual emotions.
  • Behave in ways that are not typical for you.
  • Have suicidal thoughts or actions.

Before you take varenicline, be sure to tell your doctor if you have ever had a mental illness.

FDA warning. The U.S. Food and Drug Administration (FDA) warns that people who are taking varenicline (Chantix) and who experience any serious or unusual changes in mood or behavior or who feel like hurting themselves or someone else should stop taking the medicine and call a doctor right away.

Friends or family members who notice these changes in behavior in someone who is taking varenicline (Chantix) for smoking cessation should tell the person their concerns and advise him or her to stop taking the drug and to call a doctor right away.

Varenicline is not addictive. Tell your doctor about side effects that bother you or that do not go away.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

You start taking varenicline about a week before you plan to stop smoking. You may notice that you do not get the same satisfaction from cigarettes during that week. Try not to increase your smoking to overcome this.

Tell your doctor if you:

  • Have kidney problems.
  • Are pregnant or plan to become pregnant.
  • Are breastfeeding.
  • Have ever had a mental illness such as depression or bipolar disorder .

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.



  1. Varenicline (Chantix) for tobacco dependence (2006). Medical Letter on Drugs and Therapeutics, 48(1241/1242): 66–68.


ByHealthwise Staff

Primary Medical Reviewer Adam Husney, MD - Family Medicine

Specialist Medical Reviewer Michael F. Bierer, MD - Internal Medicine,

Current as ofMay 26, 2016