Introduction:
Nicotine replacement therapy (NRT) is often used sub-optimally in smoking cessation attempts, especially when purchased over-the-counter (OTC). Previous research has focused on cognitive and attitudinal factors as potential reasons for low adherence to NRT. This study drew on theoretical frameworks of behaviour to comprehensively explore smokers’ NRT use to identify new intervention targets and improve the support offered to NRT users.

Methods:
Semi-structured face-to-face interviews were conducted with 16 adult UK-based smokers and recent ex-smokers who used NRT during quit attempts in past five years. The COM-B (Capability, Opportunity, Motivation, Behaviour) model and the Theoretical Domains Framework (TDF) informed the topic guide and analyses. Data were analysed using framework analysis in Nvivo 11.

Results:
Two related behaviours were identified relevant to optimal NRT use: use of NRT per se (B1), and engaging with information and support with NRT use (B2). A meta-theme of ‘missed opportunity’ identified instances when smokers had a chance to use NRT or get access to support, but did not or could not engage in these behaviours. For B1 these included limited ability to use and apply NRT, low motivation to optimise use, and lack of role models. For B2 they included low awareness of optimal NRT use techniques, selective information-seeking, low expectations, limited exposure to guidelines, deficient advice from healthcare professionals, and suboptimal product display. Participants often mentioned their prior suboptimal experience negatively affecting subsequent use and views. Participants expressed a need for more accessible and comprehensive guidelines on NRT.

Conclusions:
There appear to be important missed opportunities for optimal use of Nicotine Replacement Theory both in terms of use itself and access to and use of information on optimal use. These missed opportunities appear to arise from a range of capability, motivational and opportunity-related factors.

Funding:
This work was supported by AH’s 4-year British Heat Foundation PhD Studentship at UCL (FS/13/59/30649). RW and IT salaries are funded by a programme grant from Cancer Research UK (CRUK; C1417/A22962). The funding bodies had no role in the study design, data analysis or preparation of the present manuscript.