Effectiveness of Nicotine Replacement Therapy

An international team known as The Cochrane Collaboration has analyzed the results of around a hundred trials concerning nicotine replacement therapy (NRT) - 51 on chewing gums, 34 on patches, 4 on inhalers, 3 on nicotine tablets and 4 on nasal sprays (no longer commercially available). All together, these trials involved more than 35 000 male and female smokers around the world.

From this body of results, the researchers conclude that tobacco cessation is 74% higher among those undergoing NRT than among those either not undergoing NRT or using placebos such as nicotine-free patches or gum. Cessation was evaluated at 6 or 12 months after the start of treatment, depending on the study, with the vast majority of relapses occurring within the first 3 months.

Regarding chewing gums, the researchers observed that highly dependent smokers who used 4 mg nicotine gum were twice as likely to successfully complete their withdrawal as those who used 2 mg gum. Furthermore, it seems likely that using several types of products at the same time (e.g. both patches and gum) increases the chances of smoking cessation, but this subject has not yet been studied in enough depth for us to draw definitive conclusions.

Regarding patches, those worn for 16 hours (15 mg) and those worn for 4 hours (22 mg) seem to have similar levels of effectiveness.  Likewise, continuing to wear patches for more than eight weeks after quitting, or reducing the dosage gradually instead of abruptly, does not seem to improve the chances of successful withdrawal.

Although NRT boosts the odds of successful quitting, the chances are still low if no other medical or psychological support is offered in parallel. No matter the product used, trials in which quitters received extra support attained better results than those where quitters were left to their own devices.

The authors of this international analysis insist that nicotine substitutes are not a miracle solution to the complex problem of addiction. However, these products increase the chances of success, especially when accompanied by other methods (i.e. medical or psychological support). They conclude that "many smokers will need to have multiple attempts to quit using a variety of strategies before they finally succeed".

Geneva, 18 March 2004
Scientific Editor
Biologist and Smoking Cessation Specialist


Silagy C, Lancaster T, Stead L, Mant D, Fowler G. Nicotine replacement therapy for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 2, 2002.


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