title: Nicotine intake from electronic cigarettes on initial use and after 4 weeks of regular use.
abstract: BACKGROUND
  Electronic cigarettes (EC) have the potential to generate a substantial public health benefit if there is a switch from smoking to EC use on a population scale. The nicotine delivery from EC is likely to play a major role in their attractiveness to smokers. We assessed nicotine delivery from a first-generation EC and the effect of experience with its use on nicotine intake.
  
  
  METHODS
  Six smokers provided pharmacokinetic (PK) data after their first use of EC and again following 4 weeks of use.
  
  
  RESULTS
  The peak nicotine levels were achieved within 5 min of starting the EC use, which suggests that EC may provide nicotine via pulmonary absorption. There were large individual differences in nicotine intake. Compared with the PK profile when using EC for the first time, 4 weeks of practice generated a 24% increase in the peak plasma concentrations (from 4.6 to 5.7 ng/ml; nonsignificant) and a 79% increase in overall nicotine intake (AUC(0 → inf) increased from 115 to 206 ng*min/ml; p < .05).
  
  
  CONCLUSIONS
  First-generation EC provide faster nicotine absorption than nicotine replacement products, but to compete successfully with conventional cigarettes, EC may need to provide higher doses of nicotine. Nicotine intake from EC can increase with practice, but further studies are needed to confirm this effect.
authors.affiliation: Tobacco Dependence Research Unit, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK;
authors.forename: Peter
authors.initials: P
authors.lastname: Hajek
authors.affiliation: Department of Health Behavior, Roswell Park Cancer Institute, Buffalo, NY maciej.goniewicz@roswellpark.org.
authors.forename: Maciej L
authors.initials: ML
authors.lastname: Goniewicz
authors.affiliation: Tobacco Dependence Research Unit, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK;
authors.forename: Anna
authors.initials: A
authors.lastname: Phillips
authors.affiliation: Tobacco Dependence Research Unit, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK;
authors.forename: Katie
authors.initials: K
authors.lastname: Myers Smith
authors.affiliation: Tobacco Dependence Research Unit, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK;
authors.forename: Oliver
authors.initials: O
authors.lastname: West
authors.affiliation: Tobacco Dependence Research Unit, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK;
authors.forename: Hayden
authors.initials: H
authors.lastname: McRobbie
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D066300:Electronic Nicotine Delivery Systems; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D011634:Public Health; D012907:Smoking / Q000097:blood*; D000074606:Smoking Prevention; D013997:Time Factors
chemical_list: D009538:Nicotine