Effect of nicotine chewing gum on plasma nicotine levels of cigarette smokers.

This study was designed to determine whether the use of nicotine chewing gum modifies the inhalation and absorption of nicotine by cigarette smokers. Our subjects, 12 subjects who smoked cigarettes regularly, were studied for 4 days. On the first day, they smoked as usual, and on the second, third, and fourth days they also chewed a placebo gum, 2-mg nicotine gum, or 4-mg nicotine gum. They were instructed to smoke as usual throughout the study. Mean plasma nicotine concentration was 29.5 ng/ml with the placebo gum, 30.9 ng/ml with the 2-mg gum, and 40.7 ng/ml with the 4-mg gum. Peak carbon monoxide level was lower with nicotine gum than with placebo gum. Data indicate self-regulation of blood nicotine levels. The subjects appear to have compensated almost completely for the increased intake of nicotine from the 2-mg nicotine gum by decreasing the inhalation of tobacco smoke. Nicotine compensation provided by the 4-mg nicotine gum is only partial.