Our knowledge and understanding of e-cigarettes is still limited

A letter from M Cunningham exhorts “those in the profession opposed to e-cigarettes to come around in light of growing evidence” (
The Pharmaceutical Journal

2014;293:599). To support this argument, she cites the opinion of experts who spoke at a recent conference, ‘The e-cigarette summit: science, regulation and public health’, held on 13 November 2014. Although e-cigarettes have been welcomed as a safer option than smoking tobacco, it is important that we recognise the limitations in our knowledge and understanding of the benefits and harms associated with their use.

There is a general expectation that e-cigarettes provide another method of delivering nicotine replacement therapy and that such use will be successful in assisting patients to cut down or quit. In our review article (Do electronic cigarettes help with smoking cessation? Drug and Therapeutics Bulletin 2014; 52:126–129), we identified only two published randomised controlled trials that have assessed the efficacy of e-cigarettes in smoking cessation.

A study of 657 people who had expressed a desire to quit randomised them to commercially available e-cigarettes containing 16mg nicotine, 21mg nicotine patches or placebo e-cigarettes that contained no nicotine[1]
. Unfortunately, quit rates were considerably lower than expected, with the result that the study had “insufficient statistical power to conclude superiority of nicotine e-cigarettes to patches or to placebo e-cigarettes”. The second study recruited 300 regular smokers who were not intending to quit to try an e-cigarette to reduce the risk of tobacco smoking[2]
. Smokers were randomised to an e-cigarette with cartridges containing 7.2mg nicotine for 12 weeks, an e-cigarette with cartridges containing 7.2mg nicotine for six weeks followed by cartridges containing 5.4mg nicotine for six weeks, or cartridges that did not contain nicotine for 12 weeks. Reduction in smoking (≥50% reduction in the number of tobacco cigarettes/day since baseline) occurred in all three groups. There was no statistically significant difference in the results between those using nicotine-containing cartridges compared with those using no-nicotine cartridges.

Although anecdotal reports of the success of e-cigarettes in smoking cessation and survey data suggesting that e-cigarette use by those who have never smoked and long-term ex-smokers remains extremely rare are encouraging, there is still a lot that we do not know. As healthcare professionals, we have a duty to ensure that we are open and honest about the gaps in our knowledge, the limitations of the evidence surrounding the efficacy of e-cigarettes in relation to smoking cessation and the uncertainties relating to the safety of e-cigarette use. In the meantime, we believe that only products licensed for use as an aid to smoking cessation should be supplied or prescribed by healthcare professionals, and that pharmacies should not sell e-cigarettes that do not have marketing authorisation for cutting down, quitting and reducing the harms of smoking.

David Phizackerley

Deputy Editor

Drug and Therapeutics Bulletin


[1] Bullen C, Howe C, Laugesen M et al. Electronic cigarettes for smoking cessation: a randomised controlled trial. The Lancet 2013;382:1629–1637.

[2] Caponnetto P, Campagna D, Cibella F et al. Efficiency and safety of an electronic cigarette (ECLAT) as tobacco cigarettes substitute: a prospective 12-month randomized control design study. PLoS One 2013;8:e66317.

Last updated
The Pharmaceutical Journal, PJ, 17 January 2015, Vol 294, No 7845;294(7845):DOI:10.1211/PJ.2014.20067443

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