Effectiveness of Electronic Cigarettes as a Tool for Smoking Cessation or Reduction.

To examine the evidence concerning effectiveness of electronic cigarettes (e-cigarettes) in smoking cessation or reduction and reduction in desire to smoke and withdrawal symptoms. A PubMed literature search through May 2014 was performed using search terms or or ; and or limited to clinical trials in humans. Cochrane Library and International Pharmaceutical Abstracts were searched using the term . Relevant citations from identified articles were reviewed. All English-language clinical trials assessing cessation, reduction in cigarette use, desire to smoke, and/or reduction in withdrawal symptoms with e-cigarettes were included. Of 7 trials, one showed similar 6-month abstinence rates between e-cigarettes and nicotine patches. Another trial reported 12.5% of participants achieving abstinence at 24 months with e-cigarettes. Three studies demonstrated significant percentages of patients maintaining ≥50% reduction in cigarettes/day from baseline to 24 or 52 weeks. Another trial showed significant reductions in cigarette use from baseline through 52 weeks with e-cigarettes; no difference in abstinence rates beyond 12 weeks was found between nicotine and placebo e-cigarettes. Only 2 trials assessed reduction in desire to smoke or withdrawal symptoms, and results varied. The limited evidence available supports that e-cigarettes may be effective as monotherapy for smoking cessation and reduction. However, superiority to nicotine replacement therapy was not proven. Limited conclusions can be drawn regarding reduction in desire to smoke and withdrawal symptoms. The unknown long-term safety risk should also be considered.