Varenicline (Champix)
A Help to Stop Smoking

A brief overview of smoking and nicotine addiction

Nicotine is a drug that is inhaled from the tobacco in cigarettes. It gets into the bloodstream, and stimulates the brain. Most regular smokers are addicted to nicotine.

If you are a smoker, when the blood level of nicotine falls, you usually develop withdrawal symptoms such as restlessness, increased appetite, inability to concentrate, irritability, dizziness, constipation, nicotine craving, or just feeling awful. These symptoms begin within a few hours after having the last cigarette. If they are not relieved by the next cigarette, withdrawal symptoms get worse. If you do not smoke any more cigarettes, the withdrawal symptoms peak after about 24 hours, and then gradually ease over about 2-4 weeks. So, most smokers smoke regularly to feel 'normal', and to prevent withdrawal symptoms.

About 2 in 3 smokers want to stop smoking but, without help, many fail to succeed. The main reason why so few smokers succeed, even though they want to stop smoking, is because nicotine addiction is strong and difficult to break. This is where varenicline can help.

What is varenicline and how does it work?

Varenicline (trade name Champix) is a medicine that was first licensed in the UK in December 2006. It was developed to help smokers to stop smoking. Varenicline mimics the effect of nicotine on the body. Therefore, it both reduces the urge to smoke and relieves withdrawal symptoms.

The precise action of varenicline is that it interferes with the receptors in the brain that nicotine stimulates. (The nicotine in cigarettes attaches to receptors in brain cells to stimulate part of the brain - this is how nicotine has it's effect.) What varenicline does is to partly stimulate the nicotine receptors. This mimics the effects of nicotine to reduce cravings and withdrawal effects when you stop smoking. However, at the same time, it partially blocks the receptors and prevents nicotine from attaching to the receptors. This blocks or blunts the effect of nicotine in people who give in to temptation and have a cigarette.

How effective is varenicline?

It seems that about 4 in 10 smokers who want to quit smoking will be able to do so with the help of varenicline. This is better than those who are able to quite using previously available medicines (bupropion or nicotine replacement therapy - nicotine gum, spray, etc).

This figure is based on two large trials that involved several thousand smokers who wanted to quit. In the trials, smokers were randomly assigned to either varenicline plus regular counselling ('stop smoking' counselling), or bupropion plus counselling, or dummy tablets plus counselling. About 4 in 10 smokers who took varenicline had quit smoking after 12 weeks. This compared to about 3 in 10 of those who took bupropion, and just under 2 in 10 who took dummy tablets.

We must remember that the people in these trials were closely monitored and also received counselling to help them to stop smoking. Whether the same success rates will be found in the 'real world' are yet to be seen. It is also interesting to note that nearly 2 in 10 smokers in these trials were able to quit with just the counselling alone.

How do I take varenicline?

Varenicline does not 'make' you stop smoking. You still need determination to succeed, and to break the smoking habit. A combination of varenicline with counselling from a nurse, doctor, pharmacist, or other health professional is likely to increase your chance of successfully stopping smoking. Therefore, most doctors will only prescribe varenicline to people who really want to stop smoking as part of a 'stopping smoking' programme.

• You need a prescription to obtain varenicline - you cannot buy it at pharmacies.
• Decide on a 'quit date' - the date you intend to stop smoking.
• Start taking the tablets one week before the 'quit date'. The aim is to build up the dose so your body gets used to the medicine before the 'quit date'. The usual advice is to start with 0.5mg daily for the first three days. Then 0.5mg twice daily on days four to seven. Then, 1mg twice daily for 12 weeks.
• Take each dose with a full glass of water, preferably after eating. So, ideally, after breakfast, and after your evening meal.
• Tell your doctor if you develop any side-effects. A reduction in dose may be an option.

The usual course of treatment is for 12 weeks. If you have successfully stopped smoking by this time:

• In many cases, treatment is stopped and that is it. You are a non-smoker!
• In some cases, an additional 12 weeks of treatment may be advised. You can discuss this with your doctor. It may be useful for people who are not confident off the cigarettes.
• In some cases, a short 'tapering off' of the dose over a week or so may be helpful. This is because at the end of treatment, if the medicine is stopped abruptly, some people develop an increase in irritability, an urge to smoke, depression, and/or sleeping difficulty for a short time. These problems can be eased by a gradual reduction of dose.
• If you have not succeeded in quitting after 12 weeks there is no point in continuing with treatment at this time. Perhaps it is best to discuss things over with your doctor or practice nurse as to your future options.

Are there any side-effects?

Most people who take varenicline do not develop any side-effects, or they are only minor. The most commonly reported side-effect is nausea (feeling sick). This is often mild and tolerable. Nausea is thought to be less of a problem if you take the tablets just after a meal with a full glass of water.

Other reported side-effects that occur in some people include: insomnia (difficulty sleeping), abnormal dreams, headaches and flatulence (wind). Taking the evening dose after your evening meal, and not just before bedtime is thought to reduce any sleep related side-effects. See the leaflet that comes with the medicine for a full list of side-effects.

Note: varenicline is a new medicine. At the time of writing, no serious or permanent side-effects have been reported. It is still being monitored for possible side-effects as it becomes more widely used. Report any symptoms to your doctor that you feel may be caused by varenicline.

Who should not take varenicline?

Varenicline is generally thought to be a safe medicine for most people. However, it is a new medicine and so caution is used in certain people. For example, it is not licensed to be used in people who are pregnant or breastfeeding, those under the age of 18, and those with severe kidney failure. It may also be used with more caution in people who have certain conditions such as certain mental health disorders. Your doctor or practice nurse will advise if you are suitable for this medicine.

Further help and information

Quit
A charity that helps people to stop smoking.
Quitline: 0800 00 22 00    Web: www.quit.org.uk

NHS smoking helpline
Tel: 0800 169 0 169    Web www.givingupsmoking.co.uk

References

• Varenicline - Guidance for health professionals on a new prescription-only stop smoking medication. ASH. November 2006
• Gonzales D, et al. Varenicline Phase 3 Study Group. Varenicline, an alpha4beta2 nicotinic acetylcholine receptor partial agonist, vs sustained-release bupropion and placebo for smoking cessation: a randomized controlled trial. JAMA 2006;296:47-55.
• Jorenby DE, et al. Efficacy of varenicline, an alpha4beta2 nicotinic acetylcholine receptor partial agonist, vs placebo or sustained-release bupropion for smoking cessation: a randomized controlled trial. JAMA 2006;296:56-63.

© EMIS and PIP 2007   Updated: February 2007