Effectiveness of different forms of nicotine replacement therapy in helping people give up smoking

Nicotine replacement therapy (NRT) is a medicine that is available as skin patches, chewing gum, nasal and oral sprays, inhalers, lozenges and tablets that deliver nicotine through the body to the brain. In many countries, people can get NRT from healthcare professionals as well as over-the-counter, without prescriptions. The aim of NRT is to replace the nicotine that people who smoke usually get from cigarettes, so the urge to smoke is reduced and they can stop smoking altogether. We know that NRT improves a person's chances of stopping smoking and that it's a popular choice for people who want to quit.

There are many different ways to use NRT. This Cochrane Review looks at the different ways to use NRT to quit smoking, and which of these work best to quit smoking for six months or longer. It includes 63 trials including 41,509 participants. All studies were conducted in people who wanted to quit smoking, and most were conducted in adults. People enrolled in the studies typically smoked at least 15 cigarettes a day at the start of the studies.

The Cochrane authors found that using a nicotine patch and another type of NRT (such as gum or a lozenge) at the same time made it more likely that a person would successfully stop smoking than if they used one type of NRT alone. Just over 17% of people who combined a patch with another type of NRT were able to quit compared with about 14% people who used a single type of NRT .

People were also more likely to successfully quit if they used higher dose nicotine gum (containing 4mg of nicotine) in comparison to lower dose nicotine gum (containing 2mg of nicotine). Higher dose nicotine patches (containing 25mg or 21mg of nicotine) probably make it more likely that a person will quit smoking than lower dose nicotine patches (15mg or 14mg of nicotine), however more evidence is needed to strengthen this conclusion.

When people quit smoking, they often set a quit day, which is the day when they plan to stop smoking entirely. There is evidence that starting to use NRT before a quit day may help more people to quit than starting using NRT on the quit day itself, but more evidence is needed to strengthen this conclusion.

Some studies looked at the safety of different types of NRT use and found that very few people experienced negative effects and those that were mentioned were minor, such as skin irritation with patches or mouth ulcers with lozenges. NRT is considered to be a safe medication, however data on the safety of different types of NRT use in comparison to one another is sparse.

Lead author, Dr Nicola Lindson from the Nuffield Department of Primary Care Health Sciences, University of Oxford, UK said: "NRT is easy to access over the counter for people who would like to quit smoking, but many people don't use it to best effect, so their chances of giving up smoking are reduced."

"This high-quality evidence clearly signposts that the most effective way to use NRT is to use a combination of two products at once, a patch and a fast acting form such as gum, nasal spray or lozenge. Quitting this way increases the chances of you stopping smoking altogether. Some people are concerned about using two forms at the same time, but the evidence does not indicate an increased risk of harms." She added: "While this advice is included in the most recent clinical guidelines in the UK and US, incorporating these findings into training and prescribing guidelines for health professionals, and advice for individuals looking to purchase NRT will likely help more people to give up smoking."

"We tried to answer some more questions about NRT use, such as how long NRT should be used for, whether NRT should be used on a set schedule or as wanted, and whether more people stop smoking using NRT when it is provided for free versus if they have to pay for it. However, more research is needed to answer these questions."

This review is published by the Cochrane Tobacco Addiction Group. This Group has also published other evidence for people considering giving up smoking, including systematic reviews on electronic cigarettes, behaviour therapies, and other medications for quitting smoking.