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Varenicline (Champix) to help quit smoking

Last Update: August 18, 2011; Next update: 2014.

Using varenicline (trade name Champix) together with other kinds of support can increase the chances of quitting smoking. But this drug also very often has side effects.

Many people who smoke manage to stop smoking without any help. Others may use different options to increase their chances of quitting smoking. Besides nicotine replacement therapy, there are some drugs that can be used for that purpose. Due to current regulations, statutory health insurers in Germany cannot cover the cost of drugs for quitting smoking.

Studies on varenicline

Another drug that is available for people trying to quit smoking is varenicline. It has been approved for use since 2006 in the USA (under the trade name Chantix) and in Europe (under the trade name Champix). The drug is available in tablet form and has to be prescribed by a doctor. It was designed to work in two ways: First, by giving relief from the withdrawal symptoms that come when people stop smoking and second, by reducing the pleasure of smoking.

To find out more about the advantages and disadvantages of the drug, researchers from the Cochrane Collaboration reviewed studies on varenicline. They found a total of 15 studies involving more than 10,000 participants. Almost all of the studies were sponsored by the company that manufactures varenicline. In most of the studies, varenicline was compared with a dummy tablet (placebo). In some of the studies, varenicline was also compared with bupropion or nicotine replacement therapies. Most participants took 2 varenicline tablets a day at a dose of 1 milligrams (mg) per tablet.

All participants were however offered some other kind of support, for example a booklet on quitting smoking and/or regular consultations either face-to-face or on the telephone.

Varenicline can help, but it very often causes side effects

The results of the studies were as follows:

  • Quitting smoking with varenicline: Out of 100 people who took varenicline, 24 managed to stop smoking for half a year or more.
  • Quitting smoking without varenicline: Out of 100 people who only took a placebo, 11 managed to stop smoking for half a year or more.

This means that varenicline helped an additional 13 out of 100 people to stop smoking for at least half a year.

The three studies comparing varenicline with bupropion showed that varenicline had some advantages: A few more people succeeded in quitting smoking by using varenicline than did with bupropion.

The two studies that compared varenicline with nicotine replacement therapy (in this case nicotine patches) did not show any difference between the two treatments. However, the studies did not provide conclusive evidence to say whether the two options really provide the same chances of success.

Varenicline has some side effects. The most common is nausea:

  • With varenicline: 31 out of 100 people who took varenicline reported feeling nauseous at first.
  • Without varenicline: 10 out of 100 people who took a placebo reported feeling nauseous at first.

In other words, about 20 out of 100 people who took varenicline felt nauseous because of the drug.

Other frequent side effects observed in the studies included difficulty sleeping, unusual dreams and headaches. Compared with bupropion, varenicline seems to have caused less insomnia but more strange dreams.

Safety concerns expressed by authorities

Since its approval there have been several official safety warnings for this drug. The regulatory authorities in Europe (EMA) and the USA (FDA) warn that it is possible that varenicline increases the risk of heart attacks and other cardiovascular diseases. This could be particularly important for people who already have cardiovascular disease.

A review of the studies showed that, on average:

  • With varenicline: Out of 1,000 people who took varenicline about 10 reported cardiovascular complaints.
  • Without varenicline: Out of 1,000 people who took a placebo about 8 had these types of complications. 

EMA and the FDA also warn that some people had depression or suicidal thoughts and behaved unusually after using varenicline. This also affected people who had not previously had psychological illnesses, as well as people who did not stop smoking despite taking the drug.

This suggests that these changes in mood cannot only be attributed to cigarette withdrawal, but could be caused by the drug itself. EMA and the FDA advise doctors and people who use varenicline to look out for signs of behavioral or mood changes.

While quitting smoking, many people are indeed irritable and sometimes do have a depressed mood. But symptoms like lasting or worsening depression and suicidal thoughts are not common. If changes like this are noticed, the regulatory authorities recommend stopping use of the medication and seeking medical advice. Because there have also been reports of drowsiness, the FDA advises people not to drive cars or operate heavy machinery if they do not know how varenicline will affect them.

In general, the serious side effects of varenicline seem to be rare. However, there is not enough research to make any final statements about them.


  • Arzneimittelkommission der deutschen Ärzteschaft (AkdÄ). Drug Safety Mail 2008-026. Neuropsychiatrische Symptome unter Vareniclin (Champix®). Berlin: AkdÄ. 18 July 2008 (in German).
  • Cahill K, Stead LF, Lancaster T. Nicotine receptor partial agonists for smoking cessation. Cochrane Database of Systematic Reviews: Version 2010, Issue 12. CD006103 . [PubMed: 21154363]
  • European Medicines Agency (EMA). Procedural steps taken and scientific information after the authorisation: Champix. London: EMA, 2007.
  • European Medicines Agency (EMA). Champix: Anhang I. Zusammenfassung der Merkmale des Arzneimittels. London: EMA. 2008.
  • Hughes JR, Stead LF, Lancaster T. Antidepressants for smoking cessation. Cochrane Database of Systematic Reviews: Version 2009, Issue 4. CD000031 . [PubMed: 24402784]
  • Singh S, Loke YK, Spangler JG, Furberg CD. Risk of serious adverse  cardiovascular events associated with varenicline: a systematic review  and meta-analysis. CMAJ 2011; [Epub ahead of print].  [PMC free article: PMC3168618] [PubMed: 21727225]
  • Stead LF, Perera R, Bullen C, Mant D, Lancaster T. Nicotine replacement therapy for smoking cessation. Cochrane Database Systematic Reviews: Version 2008, Issue 1. CD000146. [PubMed: 23152200]
  • US Food and Drug Administration (FDA). FDA Drug Safety Communication:  Chantix (varenicline) may increase the risk of certain cardiovascular  adverse events in patients with cardiovascular disease. Rockville: FDA.  16. Juni 2011.
  • US Food and Drug Administration (FDA). Public health advisory: Important information on Chantix (Varenicline). Rockville: FDA. 1. Februar 2008.
  • US Food and Drug Administration (FDA). Information for Healthcare Professionals: Varenicline (marketed as Chantix) and Bupropion (marketed as Zyban, Wellbutrin, and generics). Rockville: FDA. 1. Juli 2009.
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