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Chapter II: Nicotine: Pharmacokinetics, Metabolism, and Phar- 

 macodynamics 



1. All tobacco products contain substantial amounts of nicotine 

 and other alkaloids. Tobaccos from low-yield and high-yield 

 cigarettes contain similar amounts of nicotine. 



2. Nicotine is absorbed readily from tobacco smoke in the lungs 

 and from smokeless tobacco in the mouth or nose. Levels of 

 nicotine in the blood are similar in magnitude in people using 

 different forms of tobacco. With regular use, levels of nicotine 

 accumulate in the body during the day and persist overnight. 

 Thus, daily tobacco users are exposed to the effects of nicotine 

 for 24 hr each day. 



3. Nicotine that enters the blood is rapidly distributed to the 

 brain. As a result, effects of nicotine on the central nervous 

 system occur rapidly after a puff of cigarette smoke or after 

 absorption of nicotine from other routes of administration. 



4. Acute and chronic tolerance develops to many effects of 

 nicotine. Such tolerance is consistent with reports that initial 



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