Nicotine replacement therapy (commonly abbreviated to NRT) is a way to give nicotine to the body by means other than tobacco. It is used to decrease withdrawal symptoms triggered by stopping smoking or chewing tobacco cessation.

A nicotine patch is applied to the left arm

Nicotine replacement therapy reduces cravings caused by nicotine addiction in smokers and chewers, helping them quit tobacco use—and thus avoid the harmful effects of smoking and chewing tobacco. The habit of smoking and chewing is both a learned behavior and a physical addiction to nicotine, therefore the use of both nicotine replacement products and counseling may help those trying to quit. The use of nicotine replacement therapy increases the success of initially quitting smoking by 50 to 70%
Nicotine replacement products are on the WHO Model List of Essential Medicines, a list of the most important medication needed in a basic health system.
The United States Public Health Service lists 7 medical agents for the stopping of tobacco, which include 5 nicotine replacement treatments (nicotine patches, gum, lozenges, inhalers, and nasal sprays) and 2 oral medications (bupropion and varenicline). Other NRT options are available, including nicotine mouth sprays and sublingual tablets.
Medical uses of nicotine patch :
Nicotine replacement therapy, in the form of gum, patches, nasal spray, inhaler and lozenges all improve the ability of people trying to quit tobacco products. Studies have shown that nicotine replacement therapy is equally as effective as medications such as bupropion, in helping people quit smoking for at least 6 months. Studies have also shown that each form of nicotine replacement therapy, including nicotine gum, patches, nasal spray, inhalers, and lozenges have similar success rates in terms of helping people stop smoking. However, the likelihood that someone will stick to a certain treatment varied, with compliance being the highest with nicotine patches, followed by nicotine gum, inhalers, and nasal sprays. It is important to note that using a few different nicotine replacement methods in combination may improve one's success rates in stopping tobacco use.Additionally, using nicotine replacement with counseling has been proven to improve tobacco abstinence rates.
Nicotine replacement products are most beneficial for heavy smokers who smoke more than 15 cigarettes per day. There are not enough studies to show that NRT helps those who smoke fewer than 10 cigarettes per day.
Side effects of nicotine patch If you are under 18 years of age, you should consult your physician before starting NRT.
Nicotine exposure during pregnancy can result in attention deficit hyperactivity disorder (ADHD) and learning disabilities in the child. It also puts the child at risk for nicotine addiction in the future. Thus, pregnant women and those who are breastfeeding should also consult a physician before initiating NRT. The gum, lozenge, and nasal spray are pregnancy category C. The transdermal patch is pregnancy category D. The transdermal patch is considered less safe for the fetus because it delivers continuous nicotine exposure as opposed to the gum or lozenge, which delivers intermittent and thus lower nicotine exposure.
Mechanism
Nicotine replacement products vary in the time it takes for the nicotine to enter the body and the total time nicotine stays in the body.
Nicotine patches are applied to the skin and continuously administer a stable dose of nicotine slowly over 16–24 hours. Nicotine gum, nicotine sprays, nicotine sublingual tablets, and nicotine lozenges administer nicotine orally with quicker nicotine uptake into the body, but lasting a shorter amount of time. Nicotine inhalers are metered-dose inhalers that administer nicotine through the lungs and mucous membranes of the throat quickly, but lasting a short amount of time. For example, blood nicotine levels are the highest 5–10 minutes after using the nicotine nasal spray, 20 minutes after using a nicotine inhaler or chewing nicotine gum, and 2–4 hours after using a nicotine patch.
Economics
Another concern relates to the fact that people may become addicted to the NRT product and turn back to tobacco products to save money. Typically, the cost of NRT lasting seven days is up to £20 over the counter, whether spray, gum or inhaler, as against £7 to £8 for twenty tax paid cigarettes, or £3 for tax paid rolling tobacco. The cost of cigarettes or tobacco over the same period varies depending on the smoker, while the cost of NRT remains static regardless of the level of nicotine it contains. This leads to the relative cost of NRT versus cigarettes or tobacco being dependent on how much the individual smokes. The British NHS provides help in the form of prescriptions, reducing the cost to £7.40 per script or for free in Scotland, and if several products are included on one script then the price will drop well below that of actual cigarettes or may even cost nothing at all.
Exempted populations
Evaluation of NRT in real-world studies produces more modest outcomes than efficacy studies conducted by the industry-funded trials. The National Health Service (NHS) in England has a smoking cessation service based on pharmacotherapy in combination with counseling support. An Action on Smoking and Health (UK) (ASH) report claims that the average cost per life year gained for every smoker successfully treated by these services is less than £1,000 (below the NICE guidelines of £20,000 per QALY (quality-adjusted life year). However, the investment in NHS stop smoking services is relatively low. A comparison with treatment costs for illicit drug users shows that £585 million is committed for 350,000 problem drug users compared to £56 million for 9 million users of tobacco. This is £6.20 for each smoker, compared to £1,670 per illegal drug user.
The claims for high efficacy and cost-effectiveness of NRT have not been substantiated in real-world effectiveness studies. Pierce and Gilpin (2002) stated their conclusion as follows: “Since becoming available over the counter, NRT appears no longer effective in increasing long-term successful cessation” (p. 1260). Efficacy studies, which are conducted using randomized controlled trials, do not transfer very well to real-world effectiveness. Bauld, Bell, McCullough, Richardson and Greaves (2009) reviewed 20 studies on the effectiveness of intensive NHS treatments for smoking cessation published between 1990 and 2007. Quit rates showed a dramatic decrease between 4-weeks and one year. A quit rate of 53% at four weeks fell to only 15% at 1 year. Younger smokers, females, pregnant smokers and more deprived smokers had lower quit rates than other groups.
In 2015, NRT sales fell for the first time since 2008 while sales for e-cigarettes continued to increase at a substantial rate. This had lead to speculation that UK smokers are trying to quit with e-cigarettes rather than traditional, pharma-backed NRT methods.
Non-prescription nicotine
Snus and nasal snuff also allow for nicotine administration outside of tobacco smoking, but do cause negative health effects.
Electronic cigarettes, also known as vapourisers or electronic nicotine delivery systems (ENDS), are often, although not always, designed to look and feel like cigarettes. They have been marketed as less harmful alternatives to cigarettes, but they are very few are as yet approved as NRTs in any jurisdiction. Some electronic cigarettes have coarsely adjustable nicotine levels. Some healthcare groups have hesitated to recommend e-cigarettes for quitting smoking, because of limited evidence of effectiveness and safety.
The U.S. Food and Drug Administration (FDA) has a list of additional tobacco products they are seeking to regulate, including electronic cigarettes.[22] The evidence suggests that the FDA accepted products such as a nicotine inhaler may be a safer way to give nicotine than e-cigarettes.
Trade names

Trade names include Nicotex, Nicorette, Nicoderm, Nicogum, Nicotinell, nicotine lozenge
Thrive and Commit Lozenge.