Using tobacco is an addiction.
Tobacco products contain nicotine, an addictive drug that is comparable to heroin or cocaine. It is a poison that can be deadly in large doses. In the amounts present in cigarettes or a can of smokeless tobacco, however, nicotine affects the chemistry of the brain and central nervous system in a way that produces both physical and mental dependency.
Because your body is addicted to nicotine, when you quit tobacco you will likely experience some discomfort due to withdrawal symptoms. These symptoms include nervousness, headaches, irritability and insomnia.
Certain medications can help control these symptoms. These include: 1) Nicotine Replacement Therapy (NRT), which is available without a prescription, and 2) Prescription Therapy, which requires a prescription from your doctor.