Table 2.

Pharmacokinetics of nicotine2,4,7,8,21

Absorption	10%–50% of available nicotine is absorbed during puffing; 80% during deep inhalation Readily and completely absorbed via mucous membranes and skin
Distribution	Readily distributed in all body tissues Reaches brain within 10 s Acute spike in arterial nicotine level occurs Steady state volume of distribution is approximately 2.6 times the body weight in kg
Metabolism	80% is metabolized in the liver to continine by enzyme CYP2A6 (and to a lesser extent by CYP2B6 and CYP2E1) Rest is metabolized in the lungs and kidneys
Elimination	Average elimination half-life is 2 h Average elimination half-life of nicotine metabolite cotinine is 16 h Cotinine is not detectable in urine after complete abstinence of 1 wk Unaltered nicotine and its metabolites excreted by kidneys