Nicotine is the substance in tobacco (present in cigarettes, cigars, and pipe and chewing tobacco) that users become dependent on. It is also the active ingredient in some drug products used to help people quit smoking.
Most nicotine exposure is from smoking tobacco, although children may accidentally eat it (usually cigarettes or butts left in ashtrays or sometimes nicotine gum or patches). In the United States, about 45 million adults smoke, and smoking is the leading cause of death. About one half of current smokers will die prematurely of a disorder caused by smoking. Smoking is so deadly because smokers inhale hundreds of other substances, including ones that can cause cancer.
About 70% of smokers acknowledge that they desire to quit smoking but are unable to do so. Of people who quit, 90% do so on their own, but only about 3 to 4% successfully quit in any given year.
Nicotine, when obtained through smoking, usually has few noticeable effects. Some people experience flushing. People who handle large amounts of tobacco leaves may absorb nicotine through their skin and develop nausea, vomiting, diarrhea, sweating, and weakness. This illness has been termed green tobacco sickness. Children who eat tobacco products can develop similar symptoms, along with agitation and confusion, sometimes from as little as one cigarette. However, serious or fatal toxicity in children is uncommon, probably because the vomiting empties the stomach.
Because smoking involves inhaling many harmful substances, it has many serious consequences. It harms nearly every organ in the body. Smoking increases the risk of coronary artery disease, lung cancer, chronic lung disorders, stroke, other cancers (such as bladder, esophageal, kidney, throat, and stomach cancers), and pneumonia. Smoking during pregnancy can cause problems such as preterm birth, a low birth weight, and sudden infant death syndrome.
Nicotine withdrawal may result in many unpleasant symptoms, including a craving for nicotine, irritability, anxiety, poor concentration, restlessness, trembling (tremor), depression, headaches, drowsiness, and stomach upset. Many people gain weight while trying to stop smoking. Withdrawal is most troublesome in severely dependent people.
Emergency treatment is rarely required except for children who have eaten products that contain nicotine. Doctors usually give them activated charcoal by mouth to absorb any drug remaining in the gastrointestinal tract. Sometimes drugs such as diazepam are used.
Most issues regarding nicotine use involve efforts to quit smoking. Most smokers who quit do so for health or economic reasons. People who want to quit smoking can get help from health care practitioners, who can provide advice and support and recommend ways to modify behavior. Other sources for help include the Internet and package inserts in nicotine replacement products.
Quitting smoking abruptly (cold turkey) is generally preferable to tapering off. Selection of a quit date is very helpful. The quit date may be random or on a special occasion (such as a holiday or anniversary). A stressful time, such as when a deadline (for example, a tax deadline) needs to be met, is not a good time to try to quit.
Behavior modification can help people change the habits that cue smoking during normal daily activities. These cues may be phone conversations, coffee breaks, meals, sexual activity, boredom, traffic problems, or other frustrations. People who recognize smoking cues may modify the cues (for example, taking a walk in place of a coffee break) or substitute another oral activity (such as sucking on candy, chewing on a toothpick, or chewing gum).
Substituting a nonsmoked version of nicotine for a time helps many people break the habit of smoking. Many nonprescroiption (over-the-counter) and prescription nicotine replacement products are available. They include nicotine chewing gum, a nicotine patch, nicotine nasal spray, and a nicotine inhaler. Using the patch with the gum or spray is more effective than any one product alone. These products have a few cautions:
Bupropion can be used with a nicotine replacement product. Together, they have a higher success rate than either alone. The results of both drugs are best when used with a behavior modification program.
A newer drug, varenicline, helps lessen craving and withdrawal symptoms and helps some people quit smoking. Nicotine replacement products and varenicline should not be used together.
If people who are depressed attempt to quit smoking, they should receive counseling. Bupropion is an antidepressant, making it particularly useful for people who are depressed or at risk of depression. Nortriptyline, another antidepressant, may be used instead.
Nicotine suppresses appetite and slightly increases the rate at which calories are burned. Thus, people who quit smoking often gain weight, which is particularly a concern among women. Exercise helps prevent weight gain and may reduce the craving for nicotine.
Support from family members and friends can help. Many U.S. states have telephone quitlines that can provide additional support for smokers trying to quit.
In the United States, about 20 million people try to quit each year. More than 90% of them return to smoking within days, weeks, or months. Receiving counseling or taking drugs improves the chances of success. About 20 to 30% of people who receive such help quit successfully. The more often people make a serious attempt to quit smoking, the more likely they are to ultimately succeed. Many people fail several times before they succeed.
Last full review/revision January 2009 by Patrick G. O'Connor, MD, MPH