Intravenous nicotine simulation of passive smoking to estimate dosage to exposed non-smokers.

Abstract

SummaryTo estimate nicotine intake from passive smoking, six subjects received slow intravenous infusions of known doses of nicotine at a steady rate over one hour. The plasma and urinary nicotine concentrations produced by the infusions were compared with those found in previous studies of non‐smokers exposed to tobacco smoke, in non‐smokers in the general population, and in smokers during and after smoking their first cigarette of the day. It was estimated that the average rate of nicotine absorption was 0.23 mg/hr in a group of non‐smokers exposed in a poorly ventilated public house, 0.36 mg/hr in non‐smokers exposed to more extreme conditions in a smoke‐filled unventilated room, and that the average daily‐life exposure of a sample of 188 urban non‐smokers was 0.014 mg nicotine per hour. In contrast, the dose absorbed by three smokers from their first cigarette of the day averaged 1.4 mg nicotine. The results indicate that when passive exposure of non‐smokers results in carbon monoxide intake equivalent to the active smoking of one cigarette, the amount of nicotine absorbed is much less ‐ equivalent to about one third of a cigarette dose. In view of the small samples and various assumptions in deriving these estimates, they can only be viewed as approximate.