Varenicline (Champix) for quitting smoking

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Varenicline (Champix) for quitting smoking


Generic NameBrand Name

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 compared to a placebo.1 And it may work better than other treatments for quitting smoking.

Side Effects

Some of the common side effects include:

  • Nausea and, in rare cases, vomiting.
  • Changes in dreaming.
  • Constipation.

Call your doctor if you feel extra sleepy or if you have depressed mood, suicidal thoughts, or changes in emotion and behaviour while you are taking this medicine.

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.

You take varenicline 2 times a day, after meals.

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. When you stop smoking, there may be a change in how these medicines work for you.

Tell your doctor if you:

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

If you have or ever had a mental illness, you may need to watch for signs of mood or behaviour change while you are taking this medicine and after you stop taking it. Your doctor may want you to try a different treatment to help you stop smoking. Champix may make current mental illness symptoms worse, or it may bring back symptoms of mental illness in people who have had mental illness.

Some studies show that varenicline helped more people quit smoking than bupropion hydrochloride (Zyban), another medicine that does not contain nicotine and helps people quit smoking.2, 1 No studies have tested if varenicline works better than nicotine replacement medicines.

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.
  2. U.S. Food and Drug Administration (2006). FDA approves novel medication for smoking cessation. FDA News. Available online:


By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer John Hughes, MD - Psychiatry
Specialist Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Last Revised August 31, 2009

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.