Efficacy of electronic cigarettes for smoking cessation.

OBJECTIVE: To review data demonstrating effective smoking cessation with electronic cigarettes (e-cigarettes). DATA SOURCES: A literature search of MEDLINE/PubMed (1946-March 2014) was performed using the search terms e-cigarettes, electronic cigarettes, and smoking cessation. Additional references were identified from a review of literature citations. STUDY SELECTION AND DATA EXTRACTION: All English-language clinical studies assessing efficacy of e-cigarettes compared with baseline, placebo, or other pharmacological methods to aid in withdrawal symptoms, smoking reduction, or cessation were evaluated. DATA SYNTHESIS: A total of 6 clinical studies were included in the review. In small studies, e-cigarettes significantly decreased desire to smoke, number of cigarettes smoked per day, and exhaled carbon monoxide levels. Symptoms of nicotine withdrawal and adverse effects were variable. The most common adverse effects were nausea, headache, cough, and mouth/throat irritation. Compared with nicotine patches, e-cigarettes were associated with fewer adverse effects and higher adherence. Most studies showed a significant decrease in cigarette use acutely; however, long-term cessation was not sustained at 6 months.
CONCLUSIONS: There is limited evidence for the effectiveness of e-cigarettes in smoking cessation; however, there may be a place in therapy to help modify smoking habits or reduce the number of cigarettes smoked. Studies available provided different administration patterns such as use while smoking, instead of smoking, or as needed. Short-term studies reviewed were small and did not necessarily evaluate cessation with a focus on parameters associated with cessation withdrawal symptoms. Though long-term safety is unknown, concerns regarding increased poisoning exposures among adults in comparison with cigarettes are alarming.