Each year, around 120,000 smokers in the UK die from smoking-related illnesses. Non-smokers are at risk, too, as second-hand tobacco smoke can increase their chances of lung cancer by as much as 19 per cent (IARC [International Agency for Research on Cancer] Monograph Volume 83: Tobacco Smoke and Involuntary Smoking, 2002).
However, as it's an addiction, smoking is a very difficult habit to break. Smokers tend to be dependent on both nicotine and the act of smoking itself. Several mainstream therapies tackle different aspects of the habit but, in isolation, their effectiveness is limited.
Bupropion (Zyban), available on prescription in the UK since 2000, is an antidepressant that acts on the part of the brain involved in addiction, and works for some 20 per cent of smokers (Expert Opin Drug Saf, 2002; 1: 303-5). But this comes with an array of side-effects - from insomnia to fatal convulsions - so is not recommended for those with a history of epilepsy; overdose can cause tachycardia and heart problems (Expert Opin Drug Saf, 2002; 1: 303-5). Given the potentially serious side-effects, the benefits of bupropion are heavily outweighed by the risks.
Nicotine replacement therapy (NRT) is also available on prescription in the UK. NRT counters nicotine-withdrawal symptoms by supplying nicotine in a way that is less harmful than smoking tobacco. It's available in a number of forms, including chewing gum, skin patches, nasal sprays, inhalers, sublingual (under the tongue) tablets and lozenges.
NRT has been found effective for smokers with all levels of addiction. In the long term, the rate of successful abstinence with NRT is about 20 per cent (the same as with bupropion), compared with 10 per cent among those who try to quit without NRT.
So far, there's no evidence that any one form of NRT is more effective than another (BMJ, 2000; 321: 355-8).
What doctors don't tell you
The crucial limitation of NRT is that it only treats nicotine addiction, which is only one aspect of the smoking habit. In addition, NRT is not always the best treatment for nicotine cravings. People who suffer from conditions such as heart disease, overactive thyroid, diabetes, severe kidney or liver disease, or stomach ulcers may find that NRT worsens the condition.
In pregnant women, NRT may have the same negative effects on the growing fetus as smoking has (NICE Technology Appraisal Guidance 38, March 2002).
As patches, NRT can cause mild skin irritation and, as inhalers and sprays, it can cause irritation to the tissues of the mouth and nose, respectively (BMJ, 2000; 321: 355-8).