There is one clinical trial.
To determine if the mu opioid receptor gene (OPRM1) A118G polymorphism moderates the subjective-rewarding effects of intravenous (IV) nicotine in male and female smokers. The subjective effects of nicotine will be measured with a Drug Effects Questionnaire, including the ratings of "good effects" and "drug liking". We hypothesize that smokers with the AG/GG genotype for the OPRM1 A118G will have attenuated subjective-rewarding effects from IV nicotine when compared to those with AA genotype.
In addition, the association of the G398A polymorphism of the CHRNA5 gene (rs16969968) with maximal response to nicotinic agonists justifies examination of this SNP as a moderator of IV nicotine sensitivity in humans (Bierut et al. 2008). --- G398A ---