Clinical pharmacology of nicotine in electronic nicotine delivery systems

Abstract

Electronic nicotine delivery systems (ENDS) are a heterogeneous class of products in which an electrically powered coil is used to heat a liquid matrix, or e-liquid, that contains nicotine, solvents (e.g. propylene glycol, vegetable glycerine) and, usually, flavourings. The user inhales the resulting aerosol, whichcontains variable concentrations of nicotine, a dependence-producing central nervous system stimulant. In many countries and certainly in the two largest markets, the European Union and the USA ENDS are regulated either as generic consumer products or as tobacco products. Products such as ENDS that are marketed to the public and contain drugs that act on the central nervous system, such as nicotine, ideally should have little potential for abuse or dependence for public health reasons. This is true, unless some level of abuse potential is desirable to maintain compliance and support substitution in place of a substance of greater potential abuse and harm. ENDS fall into this category on the basis of claims of a potential role in smoking cessation and reduction. The purpose of this background paper is to review the literature at the time of writing with some additions after review between March and December 2018 on the nicotine content and nicotine delivery of ENDS and to explore factors that influence the emissions of nicotine and non-nicotine toxicants. In addition, we review the potential role of ENDS in smoking cessation and the prospective population health impact. We also identify some relevant research gaps and make recommendations for policy.