Pharmacokinetic and subjective assessment of prototype JUUL2 electronic nicotine delivery system in two nicotine concentrations, JUUL system, IQOS, and combustible cigarette

Acute analgesic effect of nicotine vaping using three experimental pain induction tasks: a randomized, placebo-controlled laboratory study

RATIONALE

Pain and nicotine use are co-occurring conditions with a significant impact on health. Experimental evidence supports an acute analgesic effect of nicotine which may reinforce nicotine use among those with chronic pain. Evidence for nicotine analgesia have primarily been gathered in combustible cigarette users and have not been extended to electronic nicotine delivery systems (ENDS or vaping). Furthermore, the mechanisms of nicotine analgesia in humans are not well understood.

OBJECTIVES

Assess the effect of acute vaped nicotine on subjective and behavioral indices of pain sensitivity using three tasks designed to probe distinct mechanisms of analgesia.

METHODS

This study recruited ENDS users (N = 86) to undergo a paced vaping protocol followed by pain tasks in counterbalanced order. Across four sessions, participants vaped e-liquid containing nicotine or placebo, and flavor or no-flavor in a 2 × 2 within-subject design. Assessments included cold pressor, submaximal effort tourniquet to induce ischemic pain, and temporal summation of heat pain, an index of central sensitization.

RESULTS

Compared to placebo, nicotine increased cold pressor pain tolerance (ηp2 = 0.031), ischemic pain threshold (ηp2 = 0.073) and tolerance (ηp2 = 0.056) but had no effect on temporal summation of pain. Flavor did not affect pain sensitivity. Females reported greater ischemic pain sensitivity (ηp2 = 0.027) and greater reductions in craving (ηp2 = 0.086).

CONCLUSIONS

Consistent with research from tobacco smoking, analgesia may be reinforcing and contribute to nicotine dependence among ENDS users. More research on sex differences is warranted.

Nicotine flux and pharmacokinetics-based considerations for early assessment of nicotine delivery systems

In the past few years, technological advancements enabled the development of novel electronic nicotine delivery systems (ENDS). Several empirical measures such as "nicotine flux" are being proposed to evaluate the abuse liability potential of these products. We explored the applicability of nicotine flux for clinical nicotine pharmacokinetics (PK) and 52-week quit success from cigarettes for a wide range of existing nicotine delivery systems. We found that the differences in nicotine flux for various nicotine delivery systems are not related to changes in PK, as nicotine flux does not capture key physiological properties such as nicotine absorption rate. Further, the 52-week quit success and abuse liability potential of nicotine nasal sprays (high nicotine flux product), and nicotine inhalers (nicotine flux similar to ENDS) are low, suggesting that nicotine flux is a poor metric for the assessment of nicotine delivery systems. PK indices are more dependable for characterizing nicotine delivery systems, and a nicotine plasmaC max T max > 1 could improve 52-week quit success from cigarettes. However, a single metric may be inadequate to fully assess the abuse liability potential of nicotine delivery systems and needs to be further studied. A combination of in vitro and in silico approaches could potentially address the factors influencing the inhaled aerosol dosimetry and resulting PK of nicotine to provide early insights for ENDS assessments. Further research is required to understand nicotine dosimetry and PK for ad libitum product use, and abuse liability indicators of nicotine delivery systems. This commentary is intended to (1) highlight the need to think beyond a single empirical metric such as nicotine flux, (2) suggest potential PK-based metrics, (3) suggest the use of in vitro and in silico tools to obtain early insights into inhaled aerosol dosimetry for ENDS, and (4) emphasize the importance of considering comprehensive clinical pharmacology outcomes to evaluate nicotine delivery systems.

Assessment of abuse liability and switching potential of menthol-flavored pod-based electronic nicotine delivery systems among US adults who smoke cigarettes

BACKGROUND

Menthol-flavored electronic nicotine delivery systems (ENDS) are a focus of public health and regulatory policy considerations. The abuse liability of five menthol-flavored pod-based ENDS was compared to combustible cigarettes, and switching potential of ENDS was also evaluated.

METHODS

215 US adults who smoke cigarettes (34.4% female; mean age[SD]=29.60[8.75]; 40.9% non-Hispanic White; mean cigarettes/day[SD]=12.04[8.52]) completed a randomized 6-arm within-person cross-over product-use study. Participants used five pod-based menthol-flavored ENDS (JUUL2 Polar Menthol 1.5%, JUUL2 Prototype Fresh Menthol 3.0%, JUUL Menthol 5.0%, Vuse Alto Menthol 5.0%, NJOY Ace Menthol 5.0%) and their usual brand (UB) cigarette for 20minutes ad libitum. After each product use, subjective reinforcing effects relevant to abuse liability and associated with switching away from cigarettes (e.g., satisfaction, product liking) were assessed.

RESULTS

All ENDS products were rated substantially and statistically significantly lower than UB cigarette on measures of subjective reinforcing effects (ps<0.001). Satisfying effects of JUUL2 1.5% were rated significantly higher than other ENDS products. JUUL2 Prototype 3.0% and Vuse Alto 5.0% did not significantly differ (ps>0.05), and both were rated significantly higher than JUUL 5.0% and NJOY Ace 5.0% (ps<0.05). Differences in subjective responses to study products did not significantly differ by preference for menthol cigarettes or by current ENDS use.

CONCLUSIONS

Abuse liability of all menthol-flavored ENDS in this study was substantially lower than combustible cigarettes. Abuse liability of JUUL2 1.5% was within the range of currently marketed pod-based menthol-flavored ENDS products. JUUL2 1.5% likely has high potential for facilitating switching among US adults who smoke.

The Product Science of Electrically Heated Tobacco Products: An Updated Narrative Review of the Scientific Literature

Heated tobacco products represent a novel category of tobacco products in which a tobacco consumable is heated to a temperature that releases nicotine from the tobacco leaf but not to a temperature sufficient to cause combustion. Heated tobacco products may therefore have the potential to be a less harmful alternative for adult smokers who would otherwise continue to smoke cigarettes, as their use should result in exposure to substantially fewer and lower levels of toxicants. This update represents a two-year extension to our previous narrative review, which covered peer-reviewed journal articles published up to August 31, 2021. The scientific evidence published between 2021 and 2023 continues to indicate that aerosols produced from heated tobacco products contain fewer and substantially lower levels of harmful and potentially harmful constituents and that these observed reductions consistently translate to reduced biological effects in both in vitro and in vivo toxicological studies. Biomarker and clinical data from studies in which product use is controlled within a clinical setting continue to suggest changes in levels of biomarkers of exposure, biomarkers of potential harm, and clinical endpoints indicating the potential for reduced harm with switching to exclusive use of heated tobacco products in adult smokers. Overall, the available peer-reviewed scientific evidence continues to indicate that heated tobacco products offer promise as a potentially less harmful alternative to cigarettes, and as such, the conclusions of our original narrative review remain valid.

Comparing identity, attitudes, and indicators of effectiveness in people who smoke, vape or use heated tobacco products: A cross-sectional study

BACKGROUND

There is limited long-term and independent research on heated tobacco products (HTPs). We compared people who used HTPs with those who used nicotine vaping products (NVP) or cigarettes on smoker identity, indicators of effectiveness and, among NVP/HTP users, perceptions of these products.

METHODS

Adults exclusive cigarette smokers (N = 45) and ex-smokers with medium/long-term (>3months) NVP (N = 46) or HTP use (N = 45) were recruited in London, UK. Participants completed a questionnaire assessing socio-demographics, smoking characteristics, smoker identity, dependence, intention to stop and attitudes towards HTP/NVP.

RESULTS

In adjusted analysis, people who used cigarettes (Mean Difference (MD) = 1.4, 95%Confidence Intervals (CI) 0.7,2.0) and HTPs (MD = 0.8, 95%CI 0.1, 1.5) reported stronger smoker identities than those who used NVPs. Compared with smokers, HTP/NVP users had lower cravings for cigarettes (MD = 3.0, 95%CI 1.6, 4.3; MD = 3.1, 95%CI 1.9, 4.3, respectively), and higher intention to stop product use (MD = -0.8, 95%CI -1.7,-0.01; MD = -1.2, 95%CI -2.0, -0.3, respectively). People using HTPs or NVPs reported similar perceived product satisfaction (HTP:M = 3.4, 95%CI 2.8, 3.9; NVP:M = 3.0, 95%CI 2.5, 3.5), efficacy for smoking cessation (HTP:M = 4.5, 95%CI 4.2, 4.9; NVP:M = 4.6, 95%CI 4.3, 4.9) and safety (HTP:M = 2.1, 95%CI 2.0, 2.2; NVP:M = 2.0, 95%CI 1.8, 2.1). HTP users reported greater perceived addictiveness than NVPs (MD = 0.3, 95%CI 0.2, 0.6).

CONCLUSIONS

HTP and NVP users perceived products to be similarly acceptable and effective suggesting that HTPs, like NVPs, may support smoking cessation. However, since HTP use appears to maintain a stronger smoker identity and perceived addiction, this may suggest a more limited role of HTP for a permanent transition away from cigarettes.

Impact of heat-not-burn cigarette passive smoking on children's oxidative stress, endothelial and platelet function

Growing global use of heat-not-burn cigarettes (HNBC) prompts investigation. Prior studies assessed HNBC's effects on cardiovascular health, revealing heightened oxidative stress, platelet activation, and endothelial dysfunction. However, limited understanding exists regarding passive smoking's impact on children exposed to HNBC. This study aims to assess levels of oxidative stress, endothelial and platelet function among children exposed to passive smoke from HNBC, traditional tobacco (TT) cigarettes and unexposed subjects. Seventy-eight children (2-18 years) were divided into three groups: HNBC passive smokers (n = 26), TT cigarette exposed (n = 26), and control (CNT) group (n = 26, unexposed). Oxidative stress was evaluated by serum NADPH oxidase-2 (NOX2) activity, assessed by soluble Nox2-derived peptide (sNOX2-dp), isoprostanes, hydrogen peroxide (H2O2) production, hydrogen break-down activity (HBA) and NO bioavailability. Endothelial function was assessed by brachial flow-mediated dilation (FMD). Platelet function was evaluated by soluble CD40 ligand (sCD40L), soluble P-selectin (sP-selectin) and thrombus formation by T-TAS analysis. Passive smoking-exposed children (both HNBC and TT) exhibited significantly increased serum sNOX2-dp, isoprostanes, H2O2, sCD40L sP-selectin and thrombus formation versus controls. Conversely, exposed children displayed reduced brachial FMD and serum NO bioavailability. No significant differences were found between children exposed to passive smoking of HNBC vs TT. Multivariable regression linked sNOX2 (standardized coefficient β: 0.284; SE: 0.040; p = 0.01) and H2O2 (standardized coefficient β: 0.243; SE: 0.0; p = 0.02) as independent predictors of FMD, and isoprostanes (standardized coefficient β:0.388; SE: 0.022; p < 0.001) and serum cotinine (standardized coefficient β:0.270; SE: 0.048; p = 0.01) with sNOX2-dp levels. Exposure to HNBC smoke heightened oxidative stress, endothelial dysfunction, platelet activation, and thrombus formation in children. Findings suggest avenues for interventions to curb childhood passive smoking exposure.

Examining acute psychopharmacological effects of nicotine vaping versus heated tobacco products in a randomised crossover study of product naïve adult smokers

Nicotine vaping products (NVPs) and heated tobacco products (HTPs) are designed to replicate the sensory and behavioural aspects of smoking cigarettes while avoiding combustion. The success of these products as harm reduction tools will partially depend on their ability to satisfy smokers and alleviate nicotine-related withdrawal symptoms. This study aims to compare short-term effects of NVPs (Juul and Aspire PockeX) versus HTPs (IQOS) on smoking-related withdrawal relief, product satisfaction, intention to switch to NVP/HTP, perceptions and attitudes in UK adult cigarette smokers naïve to these products. In a randomized cross-over study, 45 participants visited the lab twice, at each visit trying one of the two products (NVP/HTP) and completing a questionnaire. Responses were normalized on a 0-100% scale and mean differences (MD) between NVP and HTP scores computed, with positive and negative MD values indicating greater endorsement for NVP and HTP, respectively. Cigarette cravings were reduced similarly (~ 20.0%) by both products (MD = 4.5%, 95%Confidence Interval (CI) - 4.8, 13.8). Direct positive effects (MD = - 3.5%, 95%CI - 7.2, 0.2) and adverse side effects (MD = 1.8%, 95%CI - 0.3, 3.8) were comparable after each product use, though marginally favouring HTPs. HTPs were perceived as more satisfying overall (MD = - 13.2%, 95%CI - 20.3 - 6.1) than NVPs but both were perceived as similarly addictive (MD = 3.6%, 95%CI - 4.6, 11.8), relative to cigarettes. Intention to switch to either product was comparable (MD = 4.0%, 95%CI - 5.7, 13.8). Comparison of acute use of NVP versus HTP in a sample of UK smokers naïve to these products suggests that HTPs are perceived as more satisfying than NVPs, though still less satisfying than cigarettes.Registration: The analysis plan was pre-registered, and it is available at https://osf.io/6ymdu.

Two Different Heated Tobacco Products vs. Cigarettes: Comparison of Nicotine Delivery and Subjective Effects in Experienced Users

Heated tobacco products (HTPs) produce aerosol using a different mechanism than tobacco cigarettes, leading to lower emissions of some harmful substances, but also of nicotine as reported by some independent studies. Lower nicotine delivery could lead to compensatory puffing when product use does not sufficiently satisfy cravings. Thus, this three-arm crossover study was conducted to characterize the potential of two different HTPs to deliver nicotine and satisfy cravings compared with conventional cigarettes in users who had already switched to HTPs. Fifteen active, non-exclusive HTP users consumed the study products according to a pre-directed puffing protocol. At predetermined time points, venous blood was sampled and the subjective effects of consumption were assessed. Nicotine delivery by both HTPs was comparable, but significantly lower than that by conventional cigarettes, suggesting a lower addictive potential. Cravings were reduced by all products, with no statistically significant differences between them, despite the different nicotine deliveries. This indicated that HTPs do not necessarily need high nicotine deliveries with high addictive potential, as are characteristic of tobacco cigarettes. These results were followed up on with an ad libitum use study.

Comparing the Effects of the EU- Versus the US-JUUL Pod in a Sample of UK Smokers: Nicotine Absorption, Satisfaction, and Other Nicotine-Related Subjective Effects

INTRODUCTION

Pod Vaping Devices (PVD) such as JUUL have become extremely popular in the United States although their uptake and use in the United Kingdom remain lower. A key difference between the United States and the United Kingdom is the nicotine strength legally permitted, typically 59 mg/mL in the United States but capped at 20 mg/mL in the United Kingdom and European Union. This may limit the ability of EU vaping devices to deliver satisfactory nicotine levels. The primary aim was to compare the EU- (18 mg/mL nicotine strength) with the U.S.-JUUL (59 mg/mL) on daily smokers' subjective experiences, craving relief, and blood nicotine levels.

AIMS AND METHODS

Double-blind, counterbalanced within-participants design with two conditions: 18 mg/mL versus 59 mg/mL. On two separate occasions, UK smokers (N =19, 10 males, 9 females) vaped ad libitum for 60 mins and provided blood samples at baseline 5, 15, 30, and 60 min. Subjective effects (incl. satisfaction) were measured at 10 and 60 min and, craving and withdrawal symptoms (WS) at baseline, 10 and 60 min.

RESULTS

Satisfaction did not differ between conditions. There was a significant interaction between Time and Nicotine concentration for Nicotine Hit (p = .045). Mean self-report of Nicotine Hit increased under the use of the 59 mg/mL from 10 to 60 min and decreased under the 18 mg/mL. Participants reported higher Throat Hits following use of the 59 mg/mL (p = .017). There were no differences in other subjective effects including craving, WS relief (ps > .05). Liquid consumption was doubled under the 18 versus the 59 mg/mL (p = .001) and nicotine boost was significantly higher in the 59 mg/mL at all time-points (p ≤ .001).

CONCLUSIONS

The results did not support our hypotheses that satisfaction, craving, and withdrawal reduction would be higher with the 59 mg/mL JUUL. This could be because of the doubling of liquid consumption in the 18 mg/mL. Whether satisfaction and craving relief persist over the longer-term outside of the lab remains to be determined.

IMPLICATIONS

In a 60-min ad-lib vaping session, the EU-JUUL was found to produce comparable satisfaction, craving- and withdrawal relief as the U.S.-JUUL in this sample of UK smokers. These findings could suggest that the higher nicotine concentrations available in PVDs in the United States are not necessary for providing satisfaction and improving craving and WS. However, this was at the expense of a considerable increase in liquid consumption indicative of compensatory puffing.