Prolonged exposure to denicotinized cigarettes with or without transdermal nicotine

Very low nicotine content cigarettes and potential consequences on cardiovascular disease

Cigarette smoking remains highly prevalent in the U.S. and contributes significantly to cardiovascular disease (CVD). Tobacco control policies, including product regulation, can reduce smoking-related harm. One approach being considered in the U.S. is for the FDA to set a low nicotine standard for cigarettes. Such a standard could result in multiple beneficial outcomes including reduced cardiovascular toxicity related to nicotine, reduced smoking intensity in current smokers, increased cessation rates, decreased development of smoking dependence in youth, and decreased passive smoke exposure. Consequently, CVD risk in the U.S. could be dramatically improved by nicotine reduction in cigarettes. Possible pathways linking nicotine reduction in cigarettes to decreased CVD risk are discussed, while potential unintended consequences that could offset expected gains are also presented. Gaps in the literature, including limited data on CVD biomarkers and long-term CVD outcomes following the use of very low nicotine cigarettes, are discussed to highlight areas for new research.

Transient compensatory smoking in response to placebo cigarettes

RATIONALE

To address the public health problems caused by smoking, researchers have suggested a gradual reduction in the nicotine content of cigarettes. There remain concerns, however, about the potential for smokers to compensate for reductions in nicotine content by altering their smoking behavior. Such compensatory behaviors may negate any potential cessation and/or harm reduction benefits.

OBJECTIVE

The purpose of this study was to quantify smoking behavior (e.g., puff number, volume, duration, interpuff interval, and peak flow) in response to cigarettes, varying only in nicotine content, administered repeatedly.

METHODS

Sixty-seven dependent smokers participated in this two-session, within-subject study. Moderate nicotine content and placebo cigarettes (Quest© brand) were administered in a double-blind and counterbalanced manner. Each session required 12 h of tobacco abstinence and included four ad lib smoking bouts of the condition-assigned cigarette with 40 minutes separating each bout.

RESULTS

Placebo cigarettes produced increases in total puff volume and duration and decreases in total interpuff interval relative to cigarettes with moderate nicotine content. Differences in total puff volume and duration generally dissipated across smoking bouts, with differences in total puff volume nonexistent by the third and fourth bouts.

CONCLUSIONS

Placebo cigarettes produce compensatory smoking during initial exposures; however, these effects appear to be short lived. These findings are consistent with the previous work where smoking compensation has been observed in response to a single cigarette, but not over several days of smoking.

Clinical laboratory assessment of the abuse liability of an electronic cigarette

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.

Separate and combined effects of very low nicotine cigarettes and nicotine replacement in smokers with schizophrenia and controls

INTRODUCTION

The prevalence of smoking among people with schizophrenia in the United States is about 3 times that of the general population. Novel approaches are needed to reduce rates of smoking-related morbidity and mortality among these smokers.

METHODS

This study used a within-subjects design to investigate the separate and combined effects of sensorimotor replacement for smoking (very low nicotine content [VLNC] cigarettes vs. no cigarettes) and transdermal nicotine replacement (42 mg nicotine [NIC] vs. placebo [PLA] patches) in smokers with schizophrenia (SS; n = 30) and control smokers without psychiatric illness (CS; n = 26). Each session contained a 5-hr controlled administration period in which participants underwent the following conditions, in counterbalanced order: VLNC + NIC, VLNC + PLA, no cigarettes + NIC, no cigarettes + PLA, usual-brand cigarettes + no patches. Next, participants completed measures of cigarette craving, nicotine withdrawal, smoking habit withdrawal, and cigarette subjective effects, followed by a 90-min period of ad libitum usual-brand smoking.

RESULTS

Smoking VLNC cigarettes during the controlled administration periods reduced cigarette craving, nicotine withdrawal symptoms, habit withdrawal symptoms, and usual-brand smoking in SS and CS relative to the no cigarette conditions. VLNC cigarettes were well accepted by both groups and did not affect psychiatric symptom levels in SS. Transdermal nicotine significantly reduced cigarette craving but did not affect usual-brand smoking.

CONCLUSIONS

These findings suggest that reducing the nicotine content of cigarettes to nonaddictive levels may be a promising approach for reducing nicotine dependence among people with schizophrenia.

Acute phenylalanine/tyrosine depletion reduces motivation to smoke cigarettes across stages of addiction

The neurobiology of tobacco use is poorly understood, possibly in part because the relevant mechanisms might differ depending on past nicotine exposure and degree of addiction. In the present study we investigated whether these factors might affect the role of dopamine (DA). Using the acute phenylalanine/tyrosine depletion method (APTD), DA synthesis was transiently decreased in three groups of abstinent smokers (n=47): (1) early low-frequency smokers, who had smoked a maximum of five cigarettes per day for less than one year, (2) stable low-frequency smokers smoking at the same level as early low-frequency smokers for at least 3 years, and (3) stable high-frequency smokers, who smoked a minimum of 10 or more cigarettes per day for at least 5 years. Motivation to obtain tobacco was measured using a progressive ratio breakpoint schedule for nicotine-containing and de-nicotinized cigarettes. Compared with a nutritionally balanced control mixture, APTD decreased the self-administration of nicotine-containing cigarettes, and this occurred in all three groups of smokers. The results suggest that DA influenced the willingness to sustain effort for nicotine reward, and this was seen in participants at all three levels of cigarette addiction. In the transition from sporadic to addicted use, the role of DA in the motivation to seek drug may change less than previously proposed.

If the data contradict the theory, throw out the data: Nicotine addiction in the 2010 report of the Surgeon General

The reports of US Surgeon General on smoking are considered the authoritative statement on the scientific state of the art in this field. The previous report on nicotine addiction published in 1988 is one of the most cited references in scientific articles on smoking and often the only citation provided for specific statements of facts regarding nicotine addiction. In this commentary we review the chapter on nicotine addiction presented in the recent report of the Surgeon General. We show that the nicotine addiction model presented in this chapter, which closely resembles its 22 years old predecessor, could only be sustained by systematically ignoring all contradictory evidence. As a result, the present SG's chapter on nicotine addiction, which purportedly "documents how nicotine compares with heroin and cocaine in its hold on users and its effects on the brain," is remarkably biased and misleading.

The reinforcement-enhancing effects of nicotine: implications for the relationship between smoking, eating and weight

Concerns about body weight represent an important barrier to public health efforts aimed at reducing smoking. Epidemiological studies have found that current smokers weigh less than non-smokers, smoking cessation results in weight gain, and weight restriction is commonly cited as a reason for smoking. The mechanisms underlying the relationship between smoking and weight are complex and may involve a number of factors including changes in caloric intake, physical activity, metabolic rate, and lipogenesis. Amongst these possible mechanisms, nicotine-induced enhancement of food reinforcement may be particularly important. In this paper, we first review data from our laboratory that highlight two distinct ways in which nicotine impacts reinforced behavior: 1) by acting as a primary reinforcer; and 2) by directly (non-associatively) enhancing the reinforcing effects of other stimuli. We then elaborate on the reinforcement-enhancing effects of nicotine as they pertain to behaviors and stimuli related to food. Data from both laboratory animals and humans support the assertion that nicotine enhances the reinforcing efficacy of food and suggest that the influence of these effects on eating may be most important after nicotine cessation when nicotine's effects on satiety subside. Finally, we discuss the theoretical and clinical implications of this perspective for understanding and addressing the apparent tradeoff between smoking and weight gain. Better understanding of the mechanisms underlying the reinforcement-enhancing effects of nicotine broadly, and the effects on food reinforcement per se, may aid in the development of new treatments with better long term outcomes.

New methods for tobacco dependence treatment research

INTRODUCTION

Despite advances in tobacco dependence treatment in the past two decades, progress has been inconsistent and slow. This paper reviews pervasive methodological issues that may contribute to the lack of timely progress in tobacco treatment science including the lack of a dynamic model or framework of the cessation process, inefficient study designs, and the use of distal outcome measures that poorly index treatment effects. The authors then present a phase-based cessation framework that partitions the cessation process into four discrete phases based on current theories of cessation and empirical data. These phases include: (1) Motivation, (2) Precessation, (3) Cessation, and (4) Maintenance.

DISCUSSION

Within this framework, it is possible to identify phase-specific challenges that a smoker would encounter while quitting smoking, intervention components that would address these phase-specific challenges, mechanisms via which such interventions would exert their effects, and optimal outcome measures linked to these phase-specific interventions. Investigation of phase-based interventions can be accelerated by using efficient study designs that would permit more timely development of an optimal smoking cessation treatment package.

Nicotine reduction revisited: science and future directions

Regulation of nicotine levels in cigarettes and other tobacco products is now possible with the passage of the Family Smoking Prevention and Tobacco Control Act (FSPTCA) in 2009, giving the US Food and Drug Administration (FDA) authority to regulate tobacco products, and with Articles 9-11 of the WHO Framework Convention on Tobacco Control. Both regulatory approaches allow establishing product standards for tobacco constituents, including nicotine. The FSPTCA does not allow nicotine levels to be decreased to zero, although the FDA has the authority to reduce nicotine yields to very low, presumably non-addicting levels. The proposal to reduce levels of nicotine to a level that is non-addicting was originally suggested in 1994. Reduction of nicotine in tobacco products could potentially have a profound impact on reducing tobacco-related morbidity and mortality. To examine this issue, two meetings were convened in the US with non-tobacco-industry scientists of varied disciplines, tobacco control policymakers and representatives of government agencies. This article provides an overview of the current science in the area of reduced nicotine content cigarettes and key conclusions and recommendations for research and policy that emerged from the deliberations of the meeting members.

Reinforcing effects of nicotine and non-nicotine components of cigarette smoke

RATIONALE

Nicotine and non-nicotine components of cigarette smoke contribute to its reinforcing effects; however, the specific role of each component in maintaining behavior has not yet been elucidated.

OBJECTIVES

To assess the reinforcing effects of nicotine and non-nicotine components of cigarette smoke by presenting a concurrent choice paradigm in which participants had access to intravenous (IV) nicotine infusions vs. saline (placebo) infusions and puffs from denicotinized ("denic") cigarettes vs. air (sham puffs). We also measured the effects on self-administration of prior satiation with each component.

METHODS

Sixteen smokers participated in seven sessions: 1) a baseline smoking assessment, used to tailor the nicotine dose per infusion; 2) two sessions for training discrimination of IV nicotine vs. saline infusions and denic smoke vs. sham puffs; and 3) four sessions assessing choice behavior after different satiation conditions.

RESULTS

Denic smoke was self-administered more than any other alternative, including IV nicotine. IV nicotine, however, was preferred over IV saline and sham puffs. Preference for denic smoke vs. IV nicotine was inversely correlated with subjective ratings of "comfort" associated with nicotine. Smoke satiation reduced the number of denic puffs taken during choice periods, while prior nicotine administration did not affect puffing behavior. Smoking withdrawal symptoms were alleviated both by nicotine administration and by denic smoke.

CONCLUSIONS

In established smokers, non-nicotine aspects of cigarette smoking have potent reinforcing effects. While current smoking cessation pharmacotherapies primarily address the nicotine component of cigarette addiction, future cessation strategies should also be designed to target non-nicotine factors.

The effects of nicotine, denicotinized tobacco, and nicotine-containing tobacco on cigarette craving, withdrawal, and self-administration in male and female smokers

The effects of the acute administration of nicotine [through nicotine inhalers (NI) and placebo inhalers (PI)], nicotine-containing tobacco (NT), and denicotinized tobacco (DT), on smokers' subjective responses and motivation to smoke were examined in 22 smokers (12 male, 10 female; 11 low dependent, 11 high dependent). During four randomized blinded sessions, participants self-administered NI, PI, NT, or DT, and assessed their effects using Visual Analogue Scales and the Brief Questionnaire of Smoking Urges. They could then self-administer their preferred brand of cigarettes using a progressive ratio task. NT and DT were each associated with increased satisfaction and relaxation as well as decreased craving relative to the inhalers and NT increased ratings of stimulation relative to each of the other products. Both NT and DT delayed the onset of preferred tobacco self-administration relative to NI and PI but only NT reduced the total amount self-administered. Sex differences were evident in the effects of DT on withdrawal-related cravings with women experiencing greater DT-induced craving relief than men. Findings suggest that DT is effective in acutely reducing many smoking abstinence symptoms, especially in women, but a combination of nicotine and non-nicotine tobacco ingredients may be necessary to suppress smoking behavior.