Novel delivery systems for nicotine replacement therapy as an aid to smoking cessation and for harm reduction: rationale, and evidence for advantages over existing systems.

Nicotine replacement therapy (NRT) has been used in the treatment of tobacco dependence for over three decades. Whilst the choice of NRT was limited early on, in the last ten years there has been substantial increase in the number of nicotine delivery devices that have become available. This article briefly summarises existing forms of NRT, evidence of their efficacy and use, and reviews the rationale for the development of novel products delivering nicotine via buccal, transdermal or pulmonary routes (including nicotine mouth spray, nicotine films, advanced nicotine inhalers and electronic cigarettes). It presents available evidence on the efficacy, tolerability and abuse potential of these products, with a focus on their advantages as well as disadvantages compared with established forms of NRT for use as an aid to both smoking cessation as well as harm reduction.