Nicotine increases alcohol self-administration in non-dependent male smokers

Background: Alcohol and tobacco are commonly co-administered, yet little is known about the effects of acute nicotine administration on alcohol consumption in humans. This study sought to determine how nicotine delivered by tobacco smoke influences alcohol intake in humans using a double-blind placebo controlled repeated measures design. Methods: During two randomized 120 min sessions 15 male occasional smokers smoked four nicotine-containing or four denicotinized cigarettes at 30 min intervals. Throughout the session, subjects could earn units of their preferred alcoholic beverage and glasses of water using a progressive-ratio (PR) task. Results: Wilcoxon signed-rank tests indicated that nicotine increased alcohol self-administration in a significant proportion of participants (P ≤ 0.03) without affecting water consumption (P ≥ 0.16). A two-way ANOVA supported this observation further, and, compared to denicotinized cigarettes, the nicotine-containing cigarettes increased PR breakpoints for alcohol but not water, as reflected by a Cigarette x Beverage interaction (P ≤ 0.055). Conclusions: The present data suggest that acute nicotine administration increases alcohol consumption in at least a subset of smokers.