Caution is needed with e-cigarettes

In 2013, the World Health Organization (WHO) published a report on electronic nicotine delivery systems (ENDS), known as e-cigarettes. The working party responsible showed less enthusiasm than Margaret Cunningham (
The Pharmaceutical Journal 2014;293:599
). Its appraisal of the evidence suggested that a single randomised controlled trial had shown ENDS to have a comparable (but low) efficacy to conventional nicotine replacement treatment (NRT) products. This is far from the body of growing evidence that would be enough to bring doubters round. The WHO report also expresses concern that the ENDS can “undermine efforts to denormalise tobacco use”.

ENDS may have a role in some of the instances Cunningham describes, but they are mainly promulgated on the basis of being “less awful” than smoked tobacco. Pharmacists would be left in the position of recommending products whose design and marketing seems directed towards attracting new, younger smokers. Nicotine itself is hardly free from health concerns, and the WHO report points out that it has yet to be absolved of the cardiovascular harms caused by smoking cigarettes.

Currently unregulated, ENDS show wide variation in standards of manufacture. An NHS trust near me reported an episode where a member of staff used the USB socket of their trust PC to recharge the device, and the device overheated to such an extent that the computer keyboard was damaged beyond repair. Such variation in manufacture can also result in wide differences in the dose of nicotine delivered.

With the rise in popularity of e-cigarettes, global tobacco companies are moving into the market and introducing their own versions. If these products are considered for smoking cessation, a major conflict of interest emerges in an industry hardly renowned for its transparency.

Saffari et al
[1] compared particulate metals and organic compounds released from ENDS and conventional cigarettes. The general trend is a large (around ten-fold) reduction in emissions, clearly of benefit. Despite this, metals such as nickel, zinc and silver showed higher emission rates.

Finally, this paper also confirmed the absence of polycyclic aromatic hydrocarbons from ENDS. These compounds induce activity of cytochrome p450 1A2. Pharmacists will be aware that changing from tobacco products to smoke-free versions such as ENDS or NRT products will alter CYP 1A2 status. This can have dramatic effects on clearance of some drugs, notably clozapine[2]
. I would urge pharmacists to be mindful of the potential for this serious interaction whenever a patient’s nicotine delivery method changes.


Paul Hardy


West Yorkshire



[1] Saffari A, Daher N, Ruprecht D et al. Particulate metals and organic compounds from electronic and tobacco-containing cigarettes: comparison of emission rates and secondhand exposure. Environmental Science: Processes Impacts 2014;16:2259–2267.

[2] Smith TL & Mican LM. What to do when your patient who takes clozapine enters a smoke-free facility. Current Psychiatry 2014;13:47–48.

Last updated
The Pharmaceutical Journal, PJ, 3/10 January 2015, Vol 294, No 7843/4;294(7843/4):DOI:10.1211/PJ.2014.20067407

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