Clinical laboratory assessment of the abuse liability of an electronic cigarette

Abstract

Aims: To provide an initial abuse liability assessment of an electronic cigarette (EC) in current tobacco cigarette smokers.

Design: The first of four within-subject sessions was an EC sampling session that involved six, 10-puff bouts (30 seconds inter-puff interval), each bout separated by 30 minutes. In the remaining three sessions participants made choices between 10 EC puffs and varying amounts of money, 10 EC puffs and a varying number of own brand cigarette (OB) puffs, or 10 OB puffs and varying amounts of money using the multiple-choice procedure (MCP). The MCP was completed six times at 30-minute intervals, and one choice was reinforced randomly at each trial.

Setting: Clinical laboratory.

Participants: Twenty current tobacco cigarette smokers.

Measurements: Sampling session outcome measures included plasma nicotine, cardiovascular response and subjective effects. Choice session outcome was the cross-over value on the MCP.

Findings: EC use resulted in significant nicotine delivery, tobacco abstinence symptom suppression and increased product acceptability ratings. On the MCP, participants chose to receive 10 EC puffs over an average of $1.06 or three OB puffs and chose 10 OB puffs over an average of $1.50 (P < 0.003).

Conclusions: Electronic cigarettes can deliver clinically significant amounts of nicotine and reduce cigarette abstinence symptoms and appear to have lower potential for abuse relative to traditional tobacco cigarettes, at least under certain laboratory conditions.

Figure 1

Average plasma nicotine concentration (1A), heart rate (1B), scores from QSU Factor 2 (anticipation of relief from withdrawal; 1C), and ratings of “Urge to smoke a cigarette” across six EC puffing bouts (N=20). BL indicates the baseline value (i.e. value observed at the start of the sampling session, prior to EC puffing). Filled symbols indicate a significant difference from baseline. Tukey's HSD (p < 0.05).

Figure 2

Average crossover values (i.e. the monetary value at which participants chose to receive money over 10 EC or OB puffs) collapsed across time for the OB vs. $ and EC vs. $ choice conditions. An asterisk indicates a significant effect of condition (p < 0.05).