Nicotine is an alkaloid found in the nightshade family of plants (Solanaceae), predominantly in tobacco, and in lower quantities in tomato, potato, eggplant, and green pepper. Nicotine alkaloids are also found in the leaves of the coca plant. Nicotine constitutes 0.3 to 5% of the tobacco plant by dry weight.
People sometimes start eating more when they stop smoking.
Reduced-nicotine cigarettes decreased tobacco dependence and the number of cigarettes smoked, with very little evidence of withdrawal or compensatory smoking.
Nicotine and Cancer
Nicotine functions like a growth factor, by binding to nicotine receptors on bronchial cells as well as on lung cancer cells. Nicotine promotes the growth of solid tumors in vivo, suggesting that nicotine might be contributing to the progression of tumors already initiated. Stimulation of lung cancer cells, as well as bronchial cells, with doses of nicotine leads to robust cell proliferation that is dependent on nicotine receptors. Nicotine's effects -- triggering a cascade of molecular activity in the cells and leading to tumor growth -- are "analogous to those of growth factors." While tobacco carcinogens can initiate and promote cancer, nicotine, by either cigarette substitutes or nicotine supplements, might also be a stimulant to cancer cells. Journal of Clinical Investigation, July 20, 2006.
Curr Pharm Des. 2013. Nicotine and gastrointestinal disorders: its role in ulceration and cancer development.
Am J Respir Crit Care Med. 2016. The Role of Nicotine in the Effects of Maternal Smoking During Pregnancy on Lung Development and Childhood Respiratory Disease: Implications for Dangers of E-Cigarettes. Use of e-cigarettes, especially among the young is increasing at near exponential rates. This is coupled with a perception that e-cigarettes are safe and with unlimited advertising geared towards vulnerable populations, the groups most likely to smoke or vape during pregnancy. There is now wide appreciation of the dangers of maternal smoking during pregnancy and the life-long consequences this has on offspring lung function, including the increased risk of childhood wheezing and subsequent asthma. Recent evidence strongly supports that much of the effects of smoking during pregnancy on offspring lung function is mediated by nicotine, making it highly likely that e-cigarette use during pregnancy will have the same harmful effects on offspring lung function and health as do conventional cigarettes
A novel agent with nicotine-like properties, dubbed DMXB-A, improves the mental function of patients being treated with anti-psychotic drugs for schizophrenia. As the investigators point out in the Archives of General Psychiatry, people suffering from schizophrenia are often heavy smokers and this is thought be an attempt at self-medication. Nicotinic receptors, which are involved in the brain's machinery for processing sensory input, are dysfunctional in schizophrenia.
Nicotine not allowed in Supplements
The Food and Drug Administration has informed a marketer of a product containing nicotine and labeled as a dietary supplement that the product “does not meet the definition of a dietary supplement [and] is an unapproved new drug whose marketing violates the [Federal Food, Drug, and Cosmetic Act].” The company, Nico Worldwide, Inc., Oxnard, California, had submitted a notification under Title 21 of the Code of Federal Regulation, Section 101.93 last October to inform FDA of a structure-function claim it intended to make for its product, Nic Lite ™, containing 2 to 4 mg of nicotine per 16 ounces. The product would bear the following labeling: Nicotine is a naturally occurring compound in many vegetables including cauliflower, eggplant, potatoes, and tomatoes… Dietary nicotine may help maintain a healthy smoke free lifestyle. The staff of the American Herbal Products Association (AHPA) became aware of Nic Lite ™ last Monday when Mark Ullman of Ullman, Shapiro & Ullman provided a link to a recent ABC News story on the product. ABC identified the product as “a lemon-flavored drink laced with nicotine,” sold in an 8-ounce bottle which “contains the same amount of nicotine as two cigarettes.” But AHPA staff is also aware that the federal definition of dietary supplements uses the words “other than tobacco” in describing this class of goods, and that FDA had, on July 2, 2002, expressly stated that products described as “nicotine water” should be “regarded as an unapproved new drug and cannot be legally marketed as a dietary supplement.” FDA states, "Nicotine “is an article authorized for investigation as a new drug” and cited the language in the Dietary Supplement Health and Education Act that specifically excludes any such article from use in dietary supplements. The mere presence of nicotine in foods such as cauliflower, eggplant, potatoes, and tomatoes, without any evidence that these foods were promoted for their nicotine content, does not constitute ‘marketing’ nicotine as a food or dietary supplement” under the law."
Nicotine replacement therapy
Smokers admitted to intensive care units (ICU) appear to have a higher risk of having a cardiovascular event or dying if they receive nicotine replacement therapy to prevent acute nicotine withdrawal. Hemodynamic effects of nicotine withdrawal, including increased blood pressure, heart rate and coronary artery constriction, can theoretically complicate the treatment of a critically ill patient. Nicotine replacement therapy is safe for the general medical patient. Nicotine replacement is not standard practice for ICU patients. Nicotine replacement therapy may not be safe in critically ill patients, but this does not include general medical patients in the hospital or outpatients.
Nicotine replacement therapies were used for the treatment of nicotine dependence until the early 1990s, when bupropion, the first treatment not based on nicotine, became more popular. Varenicline, a partial agonist at nicotine receptors, became available in 2006 for use in smoking cessation.
Chantix blocks nicotine receptors
Pfizer Inc. developed vareniciline drug specifically as a stop-smoking aid and has sold it in the United States since August 2006 under the brand name Chantix. Varenicline works by latching onto the same receptors in the brain that nicotine binds to when inhaled in cigarette smoke, an action that leads to the release of dopamine in the brain's pleasure centers. Taking the drug blocks any inhaled nicotine from reinforcing that effect.
Nicotine poisoning in tobacco workers
Many suffer nausea, dizziness, headache and other symptoms.
Clinical Neuropharmacology 2013. Effect of nicotine on the pharmacokinetics of levodopa. Some patients with Parkinson disease improved their symptoms on treatment with nicotine patch or gum. Nicotine has also been studied for its antidyskinetic effect on levodopa-induced dyskinesia. We determined the effects of nicotine on levodopa pharmacokinetics and gastric emptying in healthy subjects and on levodopa transport in Caco-2 monolayers in vitro. Healthy subjects received transdermal nicotine patch application followed by oral levodopa/benserazide, 100/25 mg, in a fasting state and with enteral nutrition. Levodopa pharmacokinetics was determined, and gastric emptying was evaluated by carbon 13 ((13)C)-labeled acetic acid breath testing. In vitro studies using intestinal Caco-2 cell monolayers evaluated whether the intestinal transport of levodopa was affected by nicotine and its metabolite, cotinine. Nicotine did not increase mean plasma concentration significantly during fasting or with enteral nutrition, although the extent of levodopa absorption was reduced by 34% to 60% in some individuals and the mean plasma concentration of levodopa was statistically decreased by nicotine in subjects who received enteral nutrition. However, gastric parameters were not significantly affected by nicotine. Nicotine and cotinine at 0.1 μmol/L significantly reduced levodopa uptake by Caco-2 cells. We found that nicotine reduced plasma levodopa concentration in some healthy subjects but with no alteration of gastric emptying rate. In vitro, nicotine inhibited levodopa transport by Caco-2 cell monolayers in an α-methyl amino isobutyric acid-independent, 2-amino-norbornanecarboxylic acid-dependent manner. These results suggest that nicotine may inhibit the transport of levodopa by the system L-amino acid transporter.