title: Self-titration by experienced e-cigarette users: blood nicotine delivery and subjective effects.
abstract: Self-titration is well documented in the tobacco literature. The extent to which e-cigarette users (vapers) self-titrate is unknown.
  
  
  
  This study explored the effects of high and low nicotine strength liquid on puffing topography, nicotine delivery and subjective effects in experienced vapers.
  
  
  
  Eleven experienced male vapers completed 60 min of ad libitum vaping under low (6 mg/mL) and high (24 mg/mL) nicotine liquid conditions in two separate sessions. Measurements included puffing topography (puff number, puff duration, volume of liquid consumed) and changes in plasma nicotine levels, craving, withdrawal symptoms, self-reported hit, satisfaction and adverse effects.
  
  
  
  Liquid consumption and puff number were higher and puff duration longer, in the low nicotine strength condition (all ps < 0.01). The mean difference in nicotine boost from baseline in the low condition was 8.59 (7.52) ng/mL, 16.99 (11.72) ng/mL and 22.03 (16.19) ng/mL at 10, 30 and 60 min, respectively. Corresponding values for the high condition were 33.77 (34.88) ng/mL, 35.48 (28.31) ng/mL and 43.57 (34.78) ng/mL (ps < 0.05). There were no statistically significant differences between conditions in self-reported craving, withdrawal symptoms, satisfaction, hit or adverse effects.
  
  
  
  Vapers engaged in compensatory puffing with lower nicotine strength liquid, doubling their consumption. Whilst compensatory puffing was sufficient to reduce craving and withdrawal discomfort, self-titration was incomplete with significantly higher plasma nicotine levels in the high condition.
authors.affiliation: Division of Psychology, School of Applied Sciences, London South Bank University, 103 Borough Road, London, SE1 0AA, UK. dawkinl3@lsbu.ac.uk.
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Dawkins
authors.affiliation: Drugs and Addictive Behaviours Research Group, School of Psychology, University of East London, Water lane, London, E15 4LZ, UK.
authors.forename: Catherine F
authors.initials: CF
authors.lastname: Kimber
authors.affiliation: ABS Laboratories Ltd., Biopark, Broadwater Road, Welwyn Garden City, Hertfordshire, AL7 3AX, UK.
authors.forename: Mira
authors.initials: M
authors.lastname: Doig
authors.affiliation: ABS Laboratories Ltd., Biopark, Broadwater Road, Welwyn Garden City, Hertfordshire, AL7 3AX, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Feyerabend
authors.affiliation: Medicines Research Group, School of Health, Sport and Bioscience, University of East London, Water lane, London, E15 4LZ, UK.
authors.forename: Olivia
authors.initials: O
authors.lastname: Corcoran
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D066300:Electronic Nicotine Delivery Systems; D006801:Humans; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000008:administration & dosage* / Q000097:blood; D018722:Nicotinic Agonists / Q000008:administration & dosage* / Q000097:blood; D012646:Self Administration; D057566:Self Report; D013375:Substance Withdrawal Syndrome / Q000517:prevention & control*; D013997:Time Factors; D014029:Tobacco Use Disorder / Q000503:physiopathology*; D000072137:Vaping; D055815:Young Adult
chemical_list: D018722:Nicotinic Agonists; D009538:Nicotine
keywords: Compensation; E-cigarette; Nicotine; Puffing topography; Titration