Plasma nicotine levels after smoking cigarettes with high, medium, and low nicotine yields.

Plasma nicotine three minutes after smoking a cigarette was measured in 10 sedentary workers in mid-morning and five hours later on four typical working days. The average mid-morning level after they had been smoking their usual cigarettes (mean nicotine yield 1-34 ng) was 150-4 nmol/l (24-4 ng/ml) (range 95-6-236-7 nmol/l (15-5-38-4 ng/ml)). Despite great variation between smokersthe mid-morning levels of each smoker were fairly consistent over the four mornings and correlated 0-82 with their carboxyhaemoglobin levels. After continuing to smoke their usual brand or switching to a high-nicotine brand (3-2 mg) average afternoon levels of 185-6 and 180-0 nmol/6 (30-1 and 29-2 ng/ml) respectively were not significantly higher than the morning levels, but after switching to low-nicotine cigarettes (0-14 mg) the plasma nicotine dropped to an average of 52-4 nmol/l (8-5 ng/ml). The changes between morning and afternoon while smoking usual or high-nicotine cigarettes showed marked individual variation. The findings suggest that the plasma nicotine level just after a cigarette depends more on the way the cigarette is smoked than on its nicotine yield or the number which have been smoked over the preceding few hours.