Nicotine binds with cholinergic receptors in the brain. With repeated exposure to nicotine, the number of receptors increases and the receptors also become desensitized to the chemical. As a result, the nicotine user needs progressively more nicotine to achieve the same effects. This condition, known as nicotine tolerance, is a component of nicotine dependence. The only way to lower nicotine tolerance is to reduce the amount of nicotine consumed. There are several methods for reducing and stopping nicotine intake. However, some methods may trigger nicotine withdrawal--the other component of nicotine dependence.
Stopping your nicotine consumption, also known as going "cold turkey," allows your body to reset itself and reduce its tolerance to nicotine. The number of cholinergic receptors drops and the remaining receptors become more sensitive. This process is difficult and there is an increased risk of relapse due to nicotine withdrawal. Withdrawal symptoms include depression, irritability and anxiety as well as restlessness and insomnia.
Nicotine Replacement Therapy
As the name suggests, with replacement therapy, the person substitutes her normal nicotine with another, such as a patch or gum. Nicotine replacement provides the body with progressively lower amounts of nicotine while addressing the withdrawal symptoms that normally accompany the "cold turkey" method. Over time, the body resets as it adjusts to lower amounts of nicotine.
Drugs like bupropion, also known as Zyban, and varenicline reduce the urge to smoke by preventing nicotine from binding with the cholinergic receptors in the brain. A person may continue to use nicotine but, over time, he uses progressively less and experiences fewer withdrawal symptoms. As the level of nicotine consumption drops, so does his nicotine tolerance.