Nicotine is the addictive ingredient in tobacco that causes the chronic use of tobacco products for many people. People generally feel some effects of nicotine immediately, and the pleasant effects cause them to continue to use tobacco even after they experience adverse effects. Long-term use can cause serious health problems.
Absorption
Nicotine rapidly absorbs into the bloodstream, causing adrenal glands to release hormones that stimulate the central nervous system. The stimulation temporarily increases blood pressure, respiration and heart rate. Regular smokers, however, have constantly elevated blood sugar levels because the nicotine reaction causes glucose to suppress the production of insulin.
Brain Function
Nicotine also increases levels of chemicals in parts of the brain involved with reward and pleasure, according to the National Institute on Drug Abuse. The more a person smokes, the more brain pathways become used to nicotine and expect it. The smoker eventually becomes addicted because the brain sends signals throughout the body for more of the drug. Compounds in tobacco smoke might also enhance the effects of nicotine on the brain.
Withdrawal Effects
Withdrawal symptoms occur when a smoker quits ingesting nicotine. Physical and emotional effects can include strong cravings for the drug, irritability, anxiety, depression, difficulty concentrating, frustration, restlessness, increased appetite and insomnia, according to MayoClinic.com. Many people go back to smoking because of the uncomfortable withdrawal symptoms. The addictive properties of nicotine are so strong that some people continue to smoke even after having lung or heart problems.
Potential Dangers
Nicotine itself does not cause cancer or heart disease, but its addictive powers cause people to continue smoking. The drug indirectly leads people to suffer from the other chemicals in tobacco that cause cancer, emphysema, chronic bronchitis, heart attack and stroke.
Poisoning
Nicotine poisoning, a serious condition that calls for immediate medical help, occurs when someone ingests too much nicotine, according to MedlinePlus. Sometimes young children suffer from nicotine poisoning after chewing nicotine gum or patches, the same products used to help relieve withdrawal symptoms for people trying to quit smoking. People can also get nicotine poisoning by consuming excessive amounts of the drug from using tobacco products. Symptoms include breathing difficulties, abdominal cramps, headaches, pounding or rapid heart rate, weakness and muscular twitching. In some cases, confusion, convulsions, fainting or coma can occur.
