Nicotine gum and patches do not expose the lungs to much nicotine, even from the bloodstream, according to Dr. Conti-Fine, thus its lungs-damaging effects are unlikely to be seen in patients who use such products but do not smoke. However, since smokers tend to use more of these products than non-smokers, some studies have suggested that smoking cessation may reduce a person's ability to metabolize nicotine. The main concern with using nicotine gum or patches is the possibility of developing a tolerance to its effects. With repeated use, users will need to increase the dose to achieve the same effect. This can lead to an increased risk of adverse reactions at higher doses. Users should also be aware that although nicotine gum and patches are not considered tobacco products, they cannot be used by smokers as an alternative to actual cigarettes. People who use nicotine gum or patches should not also use alcohol or take drugs and should avoid activities requiring large amounts of energy until well after taking the medication. They should also note that although these products do not contain anything close to the amount of nicotine in a cigarette, they still release the drug into the body which could affect someone with a history of heart problems or diabetes. Users should talk to their doctors about how best to stop smoking. There are various medications, programs, and other methods available that can help people quit smoking.