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Informed Health Online [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-.

Informed Health Online.

Quitting smoking: Can varenicline help and are there any serious safety concerns?

Last Update: August 18, 2011.

Young man
Using varenicline together with other kinds of support can help about 1 extra person in 8 stop smoking. But this drug could also cause some serious problems. 

Some people who smoke manage to stop smoking for a short time, but many people find it difficult to quit permanently. It is especially hard to stick with the decision because of the body’s craving for nicotine. There are, however, several drugs that can help. Due to current regulations, the statutory health insurance funds in Germany cannot cover the cost of drugs to quit smoking.

Many people who smoke use nicotine replacement therapy (NRT) as an aid to quitting, particularly in the form of nicotine patches or gum. NRT is helpful and most people can tolerate it well. You can read more about NRT here. The drug bupropion, which was originally developed to treat depression, can also help to quit smoking. However, bupropion can sometimes have serious adverse effects: occasional seizures (fits) have occurred in people using bupropion (about 1 person out of every 1,000 users). You can read more about bupropion here.

Research 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 the form of a tablet 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. It often takes some time before new drugs have been adequately tested for possible adverse effects.

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

But the treatment was not only a drug or a placebo: everyone was also offered some kind of support to help them quit, such as a booklet on quitting and/or regular consultations either face-to-face or on the telephone.

Varenicline is effective but it very often leads to adverse effects

Out of every 100 people who took varenicline, 24 stopped smoking for half a year or more (24%). By comparison, 11 out of 100 people who took a placebo succeeded in quitting (11%). This means that varenicline helped an additional 13 out of 100 people (13%) to stop smoking for at least half a year.

The 3 trials comparing varenicline with bupropion showed that varenicline had some advantages: some more people succeeded in quitting smoking by using varenicline than did with bupropion.

The 2 trials that compared varenicline with nicotine replacement therapy (in this case nicotine patches) did not show any difference between the two treatments. However, the trials were of limited conclusiveness. More research is needed on this issue.

Varenicline has some adverse effects. The most common one is nausea. It was found that 31 out of 100 people who took varenicline reported feeling nauseous at first (31%), compared to 10 out of 100 people who took a placebo (10%). In other words: about 1 out of 5 people who took varenicline felt nauseous because of the drug. Other frequent adverse effects observed in the trials include problems sleeping, strange dreams and headaches. Compared with bupropion, varenicline seems to have caused less insomnia but more strange dreams.

Safety concerns expressed by authorities

Once trials have been carried out to see how effective a drug is, the everyday use of the drug is monitored to see if there are any adverse effects. Since the above-mentioned trials finished, 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 trials showed that, on average:

  • Out of 1,000 people who took a placebo about 8 had these types of complications (0.8%).
  • Out of 1,000 people who took varenicline about 10 had these types of complications (1%).

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. The regulatory authorities are trying to increase users’ awareness of the possible adverse effects.

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 adverse effects of varenicline seem to be rare. However, there is not enough research to make any final statements about them.

Author: German Institute for Quality and Efficiency in Health Care (IQWiG)

Next planned update: August, 2014. You can find out more about how our health information is updated here.

References

  • IQWiG health information is based on research in the international literature. We identify the most scientifically reliable knowledge currently available, particularly so-called “systematic reviews”. These summarise and analyse the results of scientific research on the benefits and harms of treatments and other health care interventions. You can read more about systematic reviews and why these can provide the most trustworthy evidence about the state of knowledge here. The authors of the major systematic reviews on which our information is based are always approached to help us ensure the medical and scientific accuracy of our products.
  • Arzneimittelkommission der deutschen Ärzteschaft (AkdÄ - Drug Commission of the German Medical Association). Drug Safety Mail 2008-026. Neuropsychiatrische Symptome unter Vareniclin [Neuropsychiatric symptoms when taking varenicline] (Champix®). Berlin: AkdÄ. 18 July 2008. [Full text – 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. [Full text]
  • European Medicines Agency (EMA). Champix: Annex I. Summary of Product Characteristics. London: EMA. 2008. [Full text]
  • Hughes JR, Stead LF, Lancaster T. Antidepressants for smoking cessation. Cochrane Database of Systematic Reviews: Version 2009, Issue 4. CD000031 [Informed Health Online summary] [PubMed: 17253443]
  • 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 [Informed Health Online summary] [PubMed: 18253970]
  • 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. June 16, 2011. [Full text]
  • US Food and Drug Administration (FDA). Information for Healthcare Professionals: Varenicline (marketed as Chantix) and Bupropion (marketed as Zyban, Wellbutrin, and generics). Rockville: FDA. July 1, 2009 [Full text]
  • US Food and Drug Administration (FDA). Public health advisory: Important information on Chantix (Varenicline). Rockville: FDA. February 1, 2008 [Full text]
© IQWiG (Institute for Quality and Efficiency in Health Care)

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