Thursday, February 11, 2010

Behavioral Pharmacology Laboratory Study of Electronic Cigarettes Finds Little Nicotine Delivery, But Some Suppression of Craving for Cigarettes

The first published study of the effectiveness of electronic cigarettes was released yesterday by Tobacco Control. The study, funded by the National Cancer Institute, was conducted by Dr. Thomas Eissenberg of the Virginia Commonwealth University Behavioral Pharmacology Laboratory.

In the study, 16 smokers abstained from smoking for at least 12 hours and then smoked either their own cigarette, a sham cigarette, or one of two brands of electronic cigarettes in a laboratory setting. Subjects were instructed to take 10 puffs on their cigarette and then their plasma nicotine levels and subjective measures of their craving for a cigarette were assessed for one hour. The experiment was then repeated with 10 more puffs on the cigarette.

There were two major findings.

First, both brands of electronic cigarette delivered little to no nicotine. The plasma nicotine levels among electronic cigarette smokers were hardly distinguishable from those of sham cigarette smokers. Mean plasma nicotine levels with the electronic cigarettes never exceeded 3.5 ng/mL, while mean nicotine levels with the sham cigarette were as high as 2.0 ng/mL and mean nicotine levels with regular cigarettes reached as high as 20.0 ng/mL.

Second, the electronic cigarettes were less effective than regular cigarettes in reducing cigarette cravings. One of the electronic cigarette brands failed to produce any significant reduction in craving. However, the second electronic cigarette brand appears to have reduced cigarette craving, an effect which was statistically significant in one of the two trials (the second one).

The paper concludes: "Relative to a tobacco cigarette, 10 puffs from either of these electronic nicotine delivery devices (E-cigarettes) with a 16 mg nicotine cartridge delivered little to no nicotine an suppressed craving less effectively."

Importantly, the paper notes that the number of puffs taken by the e-cigarette users was limited and thus may not simulate real vaping conditions, where vapers may take more puffs with greater intensity (i.e., puff volume).

As Dr. Eissenberg notes: "Importantly, these results were from two specific products tested under acute conditions in which puff number was controlled. Variability in product design may influence vapour content and chronic use and/or more intensive puffing (i.e., more puffs, greater puff volume) may influence nicotine delivery. Given these and other factors, there is an ongoing need to evaluate electronic nicotine delivery devices (E-cigarettes)."

The Rest of the Story

To me, the most remarkable finding of this study is that in at least one trial of one of the e-cigarette brands, there was a significant suppression of the craving for cigarettes despite the lack of any evidence of significant nicotine delivery.

This means that the behavioral stimuli alone (i.e., simulation of the act of cigarette smoking) were sufficient to reduce the craving for cigarettes, even without any significant level of nicotine being delivered.

As I discussed yesterday, there is previous research (also conducted by Dr. Eissenberg) which demonstrates the suppression of some smoking abstinence symptoms (most notably, the urge to smoke) by denicotinized cigarettes. Thus, it may be that the simulation of the act of smoking, which electronic cigarettes provide, can - in some situations - help suppress the urge to smoke. This might be an explanation for the anecdotal observation that many vapers have found electronic cigarettes to be helpful in allowing them to quit smoking and stay off cigarettes for long periods of time.

Of course, it is important to note that this study was conducted under laboratory conditions in which subjects were instructed to take 10 puffs. It is not clear what results might have occurred if smokers were permitted to smoke freely and as intensively as they desired. It is also possible that it takes some "practice" for vapers to be able to effectively obtain nicotine from electronic cigarettes.

For these reasons, the results of this study should be interpreted cautiously and this provocative research should stimulate further studies to help clarify the answers to these outstanding questions.

In summary, I believe that based on these research results, electronic cigarettes remain a very promising innovation that could potentially play an important role in promoting smoking cessation, especially in the absence of any effective alternatives. If it is true that these devices might even suppress the urge to smoke without delivering nicotine, then the possibility for a safe alternative to cigarette smoking may truly exist. Even if some delivery of nicotine is necessary, these devices could well present a safer alternative to smoking.

Further research on electronic cigarettes should now be a public health priority. Instead of banning these devices and relegating them to history, the FDA should embrace the possibility that these devices could make a miraculous contribution to smoking cessation and should actively help, and work with manufacturers and distributors to gather the evidence necessary to determine whether these devices can have an important role in the nation's smoking cessation strategy.

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