Discriminative stimulus effects of nicotine in humans

Considering Drug-Associated Contexts in Substance Use Disorders and Treatment Development

Environmental contexts that are reliably associated with the use of pharmacologically active substances are hypothesized to contribute to substance use disorders. In this review, we provide an updated summary of parallel preclinical and human studies that support this hypothesis. Research conducted in rats shows that environmental contexts that are reliably paired with drug use can renew extinguished drug-seeking behavior and amplify responding elicited by discrete, drug-predictive cues. Akin to drug-associated contexts, interoceptive drug stimuli produced by the psychopharmacological effects of drugs can also influence learning and memory processes that play a role in substance use disorders. Findings from human laboratory studies show that drug-associated contexts, including social stimuli, can have profound effects on cue reactivity, drug use, and drug-related cognitive expectancies. This translationally relevant research supports the idea that treatments for substance use disorders could be improved by considering drug-associated contexts as a factor in treatment interventions. We conclude this review with ideas for how to integrate drug-associated contexts into treatment-oriented research based on 4 approaches: pharmacology, brain stimulation, mindfulness-based relapse prevention, and cognitive behavioral group therapy. Throughout, we focus on alcohol- and tobacco-related research, which are two of the most prevalent and commonly misused drugs worldwide for which there are known treatments.

Research on Behavioral Discrimination of Nicotine May Inform FDA Policy on Setting a Maximum Nicotine Content in Cigarettes

INTRODUCTION

The Food and Drug Administration may set a maximum nicotine content in cigarettes to minimize smoking's addictiveness. Our recent research may indirectly support setting levels applicable to the population of dependent smokers below 1 mg/g (mg nicotine/g of tobacco filler).

METHODS

Using a within-subjects design in laboratory-based studies totaling 61 nontreatment seeking adult dependent smokers, Spectrum research cigarettes with nicotine contents ranging from 1.3 to 17 mg/g (just one per session) were compared with the lowest content available, 0.4 mg/g. Identified for each participant was the smallest difference in nicotine content, or "threshold," between cigarettes that still supported behavioral discrimination (ie, ability to objectively distinguish their difference). The next lower nicotine content cigarette, not discriminated (by definition), was labeled their "subthreshold." Subjective perceptions and choice behavior were also assessed.

RESULTS

Thresholds varied widely among all 61 smokers but, importantly, fewer than 7% of smokers could discriminate the two lowest, 1.3 versus 0.4 mg/g nicotine, meaning more than 90% could not do so. Moreover, we found a consistent association between their nicotine discrimination threshold and their subjective perceptions and subsequent reinforcement behavior later in the session. Specifically, a participant's discrimination threshold cigarette was also more highly rated and preferred (ie, self-administered), whereas their subthreshold cigarette was rated similarly to the 0.4 mg/g and not preferred.

CONCLUSIONS

Cigarette nicotine content below the threshold for perceiving nicotine's effects (ie, its discriminability) in nearly all smokers from a no nicotine comparison is likely below 1.0 mg/g, or less than or equal to 10% of that in typical commercial cigarettes.

IMPLICATIONS

Cigarettes with nicotine contents able to be discriminated (threshold) are also reinforcing, and those unable to be discriminated are not reinforcing, as anticipated. Yet, research explicitly comparing cigarettes with contents below 1.0 mg/g versus no nicotine (ie, a "placebo") is needed with larger samples. Results may confirm what nicotine content lower than 1.0 mg/g is below the threshold for discrimination (and self-administration) in the vast majority (>95%) of adult dependent smokers as well as teens beginning to smoke. Identifying that content would strongly support the Food and Drug Administration policy to establish a maximum nicotine content in cigarettes that will not maintain dependence.

Cross-Species Translational Findings in the Discriminative Stimulus Effects of Ethanol

The progress on understanding the pharmacological basis of ethanol's discriminative stimulus effects has been substantial, but appears to have plateaued in the past decade. Further, the cross-species translational efforts are clear in laboratory animals, but have been minimal in human subject studies. Research findings clearly demonstrate that ethanol produces a compound stimulus with primary activity through GABA and glutamate receptor systems, particularly ionotropic receptors, with additional contribution from serotonergic mechanisms. Further progress should capitalize on chemogenetic and optogenetic techniques in laboratory animals to identify the neural circuitry involved in mediating the discriminative stimulus effects of ethanol. These infrahuman studies can be guided by in vivo imaging of human brain circuitry mediating ethanol's subjective effects. Ultimately, identifying receptors systems, as well as where they are located within brain circuitry, will transform the use of drug discrimination procedures to help identify possible treatment or prevention strategies for alcohol use disorder.

Preliminary test of cigarette nicotine discrimination threshold in non-dependent versus dependent smokers

BACKGROUND

Despite its potential for understanding tobacco dependence, behavioral discrimination of nicotine via smoking has not been formally examined as a function of nicotine dependence level.

METHODS

Spectrum research cigarettes were used to compare non-dependent with dependent smokers on the lowest content of nicotine they could discriminate (i.e., "threshold"). Dependent (n=21; 16M, 5F) or non-dependent (n=7; 4M, 3F) smokers were tested on ability to discriminate between cigarettes with nicotine contents of 17, 11, 5, 2, and 1mg/g, one per session, from an "ultra-low" cigarette with 0.4mg/g (all had 9-10mg "tar"). All abstained from smoking overnight prior to sessions, and number of sessions was determined by the lowest nicotine content they could reliably discriminate from the ultra-low on >80% of trials (i.e., ≥5 of 6). Subjective perceptions and cigarette choice behavior were also assessed and related to discrimination behavior.

RESULTS

Discrimination thresholds (and most perceptions) did not differ between dependent and non-dependent smokers, with median thresholds of 11mg/g for both subgroups. Yet, "liking" and puff choice for threshold cigarettes were greater in dependent but not non-dependent smokers, while cigarettes with nicotine contents below threshold did not support "liking" or choice in both groups.

CONCLUSIONS

In sum, this preliminary study suggests threshold for discriminating nicotine via smoking may not vary by dependence level, and further study is needed to confirm that cigarettes unable to be discriminated are also not reinforcing.

Threshold dose for behavioral discrimination of cigarette nicotine content in menthol vs. non-menthol smokers

RATIONALE

The lowest threshold content (or "dose") of nicotine discriminated in cigarettes may differ due to menthol preference.

OBJECTIVES

Menthol and non-menthol Spectrum research cigarettes differing in nicotine content were used to determine discrimination thresholds.

METHODS

Dependent smokers preferring menthol (n = 40) or non-menthol (n = 21) brands were tested on ability to discriminate cigarettes (matched for their menthol preference) with nicotine contents of 16-17, 11-12, 5, 2, and 1 mg/g, one per session, from an "ultra-low" cigarette with 0.4 mg/g. Controlled exposure to each cigarette was four puffs/trial, and the number of sessions was determined by the lowest nicotine content they could discriminate on >80% of trials (i.e., ≥5 of 6). We also assessed subjective perceptions and behavioral choice between cigarettes to relate them to discrimination responses.

RESULTS

Controlling for Fagerstrom Test of Nicotine Dependence score, discrimination thresholds were more likely to be at higher nicotine content cigarettes for menthol vs. non-menthol smokers (p < .005), with medians of 16 vs. 11 mg/g, respectively. Compared to the ultra-low, threshold and subthreshold (next lowest) cigarettes differed on most perceptions and puff choice, but menthol preference did not alter these associations. Notably, threshold cigarettes did, but subthreshold did not, increase choice over the ultra-low.

CONCLUSIONS

Threshold for discriminating nicotine via smoking may be generally higher for menthol vs. non-menthol smokers. More research is needed to identify why menthol smoking is related to higher nicotine thresholds and to verify that cigarettes unable to be discriminated do not support reinforcement.

Tobacco Influence on Taste and Smell: Systematic Review of the Literature

Introduction  In Brazil, estimates show that 14.7% of the adult population smokes, and changes in smell and taste arising from tobacco consumption are largely present in this population, which is an aggravating factor to these dysfunctions.

Objectives  The objective of this study is to systematically review the findings in the literature about the influence of smoking on smell and taste.

Data Synthesis  Our research covered articles published from January 1980 to August 2014 in the following databases: MEDLINE (accessed through PubMed), LILACS, Cochrane Library, and SciELO. We conducted separate lines of research: one concerning smell and the other, taste. We analyzed all the articles that presented randomized controlled studies involving the relation between smoking and smell and taste. Articles that presented unclear methodologies and those whose main results did not target the smell or taste of the subjects were excluded. Titles and abstracts of the articles identified by the research strategy were evaluated by researchers. We included four studies, two of which were exclusively about smell: the first noted the relation between the perception of puff strength and nicotine content; the second did not find any differences in the thresholds and discriminative capacity between smokers and nonsmokers. One article considered only taste and supports the relation between smoking and flavor, another considered both sensory modalities and observes positive results toward the relation immediately after smoking cessation.

Conclusion  Three of the four studies presented positive results for the researched variables.

Acute effects of snus in never-tobacco users: a pilot study

BACKGROUND

Snus tobacco characteristics may attract non-tobacco users, including relatively low, but pharmacologically active, doses of nicotine. Lower nicotine doses may limit adverse drug effects while also producing a physiologically active response.

OBJECTIVES

This pilot study is the first to profile the acute effects of snus on physiological and subjective assessments in a sample of never-tobacco users.

METHODS

Eleven never-tobacco users (five women; <100 uses/lifetime) were recruited from the community via university-approved advertisements. Using a within-subject design, participants consumed six pouches in ascending dose order (0, 1.6, 3.2, 4.8, 6.4, and 8.0 mg nicotine) within one session. The start of each snus bout was separated by 45 minutes, and pre- and post-pouch assessments included ratings of drug effects and physiological response.

RESULTS

The average heart rate and systolic blood pressure increased significantly from pre- to post-pouch use as a function of dose, though these increases were reliable for 8.0 mg nicotine only (p < .05). Collapsed across time, diastolic blood pressure was significantly higher for 8.0 mg nicotine than for all other doses (p < .05). Subjective ratings for "excessive salivation" and "satisfying" increased significantly from pre- to post-pouch use (p < .05), independent of dose.

CONCLUSION

Significant increases in physiological response at some doses suggest that users were exposed to pharmacologically active doses of nicotine. The lack of reliable subjective effects may be the product of the dosing regimen or the relatively small sample size. Findings highlight the need for identification of doses of snus that may promote abuse among naïve users.

Attenuated nicotine-like effects of varenicline but not other nicotinic ACh receptor agonists in monkeys receiving nicotine daily

BACKGROUND AND PURPOSE

Chronic treatment can differentially impact the effects of pharmacologically related drugs that differ in receptor selectivity and efficacy.

EXPERIMENTAL APPROACH

The impact of daily nicotine treatment on the effects of nicotinic ACh receptor (nAChR) agonists was examined in two groups of rhesus monkeys discriminating nicotine (1.78 mg·kg-1 base weight) from saline. One group received additional nicotine treatment post-session (1.78 mg·kg-1 administered five times daily, each dose 2 h apart; i.e. Daily group), and the second group did not (Intermittent group).

KEY RESULTS

Daily repeated nicotine treatment produced a time-related increase in saliva cotinine. There was no significant difference in the ED50 values of the nicotine discriminative stimulus between the Daily and Intermittent group. Mecamylamine antagonized the effects of nicotine, whereas dihydro-β-erythroidine did not. Midazolam produced 0% nicotine-lever responding. The nAChR agonists epibatidine, RTI-36, cytisine and varenicline produced >96% nicotine-lever responding in the Intermittent group. The respective maximum effects in the Daily group were 100, 72, 59 and 28%, which shows that the ability of varenicline to produce nicotine-like responding was selectively decreased in the Daily as compared with the Intermittent group. When combined with nicotine, both varenicline and cytisine increased the potency of nicotine to produce discriminative stimulus effects.

CONCLUSION AND IMPLICATIONS

Nicotine treatment has a greater impact on the sensitivity to the effects of varenicline as compared with some other nAChR agonists. Collectively, these results strongly suggest that varenicline differs from nicotine in its selectivity for multiple nAChR subtypes.

Assessing Discrimination of Nicotine in Humans Via Cigarette Smoking

INTRODUCTION

Nicotine's interoceptive stimulus effects likely help explain smoking's reinforcing efficacy, but human studies have been limited by difficulties controlling dosing via tobacco inhalation. Our objective was to describe a procedure to study nicotine discrimination via smoking.

METHODS

Dependent smokers abstinent overnight (>12 hours) were first "trained" to discriminate between two cigarettes differing in nicotine content, based on four puffs of exposure, and then tested on whether they successfully acquired that discrimination. After piloting with Quest brand commercial cigarettes, 29 subjects engaged in the main study with cigarettes available through NIDA (Spectrum; 16mg vs. 0.4mg nicotine content). Discrimination training first involved two trials, one with each cigarette, prior to six testing trials. Due to results with the first 20 subjects, the remaining nine received two training trials with each cigarette (four total). Subjective perceptions were also assessed during each testing trial, and puff choice between the two cigarettes available concurrently was assessed after testing, on the last two trials.

RESULTS

All five pilot subjects successfully discriminated Quest 1 versus Quest 3 (defined by at least five out of six trials correct, ie, >80%). Yet, only 10 of 20 subjects (50%) were able to discriminate the two Spectrum cigarettes based on two training trials. After changing to four training trials, eight of nine subjects were able to discriminate (89%). Subjective perceptions and puff choice differed between cigarettes more in those able versus unable to discriminate them.

CONCLUSIONS

With sufficient training exposures, smokers can discriminate nicotine between cigarettes differing in nicotine contents.

IMPLICATIONS

The interoceptive stimulus effects of nicotine are critical to understanding reinforcement from cigarette smoking behavior. Because of the very recent availability of Spectrum research cigarettes from NIDA, with specific known amounts of nicotine content, the study of nicotine discrimination in humans via cigarette smoking may now be feasible. Our results demonstrate that, with sufficient training, smokers can behaviorally discriminate nicotine from four puffs' exposure between cigarettes differing in nicotine contents. Future research should evaluate human discrimination of nicotine from greater amounts of cigarette smoke exposure, as well as in response to other procedural variations.

Threshold dose for discrimination of nicotine via cigarette smoking

RATIONALE

The lowest nicotine threshold "dose" in cigarettes discriminated from a cigarette containing virtually no nicotine may help inform the minimum dose maintaining dependence.

OBJECTIVES

Spectrum research cigarettes (from NIDA) differing in nicotine content were used to evaluate a procedure to determine discrimination thresholds.

METHODS

Dependent smokers (n = 18; 13 M, 5 F) were tested on ability to discriminate cigarettes with nicotine contents of 11, 5, 2.4, and 1.3 mg/g, one per session, from the "ultralow" cigarette with 0.4 mg/g, after having discriminated 16 mg/g from 0.4 mg/g (all had 9-10 mg "tar"). Exposure to each was limited to 4 puffs/trial. All subjects were abstinent from smoking overnight prior to each session, and the number of sessions was determined by the participant's success in discrimination behavior on >80 % of trials. Subjective perceptions and behavioral choice between cigarettes were also assessed and related to discrimination behavior.

RESULTS

The median threshold was 11 mg/g, but the range was 2.4 to 16 mg/g, suggesting wide variability in discrimination threshold. Compared to the ultralow, puff choice was greater for the subject's threshold dose but only marginal for the subthreshold (next lowest nicotine) cigarette. Threshold and subthreshold also differed on subjective perceptions but not withdrawal relief.

CONCLUSIONS

Under these testing conditions, threshold content for discriminating nicotine via cigarettes may be 11 mg/g or greater for most smokers, but some can discriminate nicotine contents one-half or one-quarter this amount. Further study with other procedures and cigarette exposure amounts may identify systematic differences in nicotine discrimination thresholds.

Sex Differences in Behavioral Dyscontrol: Role in Drug Addiction and Novel Treatments

The purpose of this review is to discuss recent findings related to sex differences in behavioral dyscontrol that lead to drug addiction, and clinical implications for humans are discussed. This review includes research conducted in animals and humans that reveals fundamental aspects of behavioral dyscontrol. The importance of sex differences in aspects of behavioral dyscontrol, such as impulsivity and compulsivity, is discussed as major determinants of drug addiction. Behavioral dyscontrol during adolescence is also an important consideration, as this is the time of onset for drug addiction. These vulnerability factors additively increase drug-abuse vulnerability, and they are integral aspects of addiction that covary and interact with sex differences. Sex differences in treatments for drug addiction are also reviewed in terms of their ability to modify the behavioral dyscontrol that underlies addictive behavior. Customized treatments to reduce behavioral dyscontrol are discussed, such as (1) using natural consequences such as non-drug rewards (e.g., exercise) to maintain abstinence, or using punishment as a consequence for drug use, (2) targeting factors that underlie behavioral dyscontrol, such as impulsivity or anxiety, by repurposing medications to relieve these underlying conditions, and (3) combining two or more novel behavioral or pharmacological treatments to produce additive reductions in drug seeking. Recent published work has indicated that factors contributing to behavioral dyscontrol are an important target for advancing our knowledge on the etiology of drug abuse, intervening with the drug addiction process and developing novel treatments.

Effects of the Nanoparticle-Based Vaccine, SEL-068, on Nicotine Discrimination in Squirrel Monkeys

A key feature of addiction to nicotine likely resides in its ability to produce subjective effects that, in turn, may be reflected in its discriminative-stimulus properties. Vaccination against such effects of nicotine offers an intriguing therapeutic approach for smoking cessation, but a reliably effective and immunologically safe vaccine remains to be identified. Here we report on the ability of SEL-068, a nanoparticle-based vaccine that targets nicotine, to modify the discriminative-stimulus effects of nicotine in a primate species. Results indicate that squirrel monkeys vaccinated with SEL-068 failed to acquire 0.1 mg/kg nicotine discrimination but readily learned to discriminate 0.001 mg/kg of the nicotinic full agonist (+)-epibatidine ((+)-EPI). After (+)-EPI training, doses of nicotine ⩾ 0.32 mg/kg, which produced behaviorally adverse actions, still failed to substitute for the (+)-EPI training stimulus in immunized monkeys, whereas (+)-EPI and the partial agonist varenicline engendered, respectively, complete and partial substitution in all monkeys with potency comparable to their potency in non-immunized subjects. In other subjects, nicotine was trained as a discriminative-stimulus and then replaced by (+)-EPI. Subsequent vaccination with SEL-068 led to a threefold and long-lasting (>30 weeks) decrease in the potency of nicotine but not (+)-EPI or varenicline. Collectively, our results show that SEL-068 can block the development of nicotine discrimination and attenuate nicotine's effects in nicotine-experienced monkeys without altering the discriminative-stimulus properties of other nicotinic drugs. The difference in the vaccine's effects in naive and nicotine-experienced subjects provides important insight into the conditions under which immunotherapy may be effective in combating nicotine addiction.

Sex differences in hormonal responses to stress and smoking relapse: a prospective examination

INTRODUCTION

Dysregulation in the hypothalamic-pituitary-adrenal axis has been shown to be associated with smoking relapse. No study has directly examined the role of sex differences in this relationship.

METHODS

Nicotine dependent men (n = 52) and women (n = 46) interested in cessation completed 2 laboratory stress sessions during ad libitum smoking and after 48 hr of abstinence. The laboratory session included baseline, stress, and recovery periods. Blood and saliva samples were collected at the end of each period for the measurement of cortisol and adrenocorticotropic hormone. Self-report measures of craving and withdrawal symptoms were also collected. Participants attended 4 weekly follow-up sessions for counseling where they provided biological samples and self-report measures including smoking status. Relapse was defined by smoking cigarettes for 7 consecutive days post-cessation.

RESULTS

Results showed that 60 participants relapsed during the 4-week period. Cox regression models from the abstinence session showed that cortisol levels regardless of source were predictive of relapse but the direction of prediction was sex dependent (Sex × Hormone, all ps < .05). Follow-up analyses further revealed that lower cortisol levels predicted relapse in men whereas greater cortisol levels predicted relapse in women (ps < .05). Enhanced craving predicted early smoking relapse in men but not in women (ps < .05). Data from the ad libitum session showed no differences in predicting relapse.

CONCLUSION

These findings highlight that sex differences in the hormonal response to stress and subjective craving during nicotine withdrawal are critical predictors of risk for understanding early relapse.

Subjective, physiological, and cognitive responses to intravenous nicotine: effects of sex and menstrual cycle phase

Nicotine dependence is a serious public health concern. Optimal treatment of nicotine dependence will require greater understanding of the mechanisms that contribute to the maintenance of smoking behaviors. A growing literature indicates sex and menstrual phase differences in responses to nicotine. The aim of this study was to assess sex and menstrual phase influences on a broad range of measures of nicotine response including subjective drug effects, cognition, physiological responses, and symptoms of withdrawal, craving, and affect. Using a well-established intravenous nicotine paradigm and biochemical confirmation of overnight abstinence and menstrual cycle phase, analyses were performed to compare sex (age 18-50 years; 115 male and 45 female) and menstrual cycle phase (29 follicular and 16 luteal) effects. Females had diminished subjective drug effects of, but greater physiological responses to, nicotine administration. Luteal-phase females showed diminished subjective drug effects and better cognition relative to follicular-phase women. These findings offer candidate mechanisms through which the luteal phase, wherein progesterone is dominant relative to estradiol, may be protective against vulnerability to smoking.

The reinforcement threshold for nicotine as a target for tobacco control

BACKGROUND

Cigarette smoking represents an enormous public health problem worldwide that leads to over 5 million deaths per year. The gradual reduction of the nicotine content of cigarettes below the threshold that is required to develop addiction is one strategy that might substantially reduce the number of addicted smokers and prevent adolescents from becoming addicted to nicotine (Benowitz and Henningfield, 1994). While the potential public health benefits of this approach are enormous, the guiding concepts and relevant empirical evidence needed to support the implementation of a nicotine reduction policy require a critical examination.

METHODS

The purpose of this paper is to briefly review the current concepts and research regarding nicotine reduction while also discussing the utility of the addictive threshold for nicotine in this approach. The accurate determination of the nicotine addiction threshold presents some conceptual challenges as there is a lack of consensus on how to best measure nicotine addiction. This difficulty can impede the progress for developing a science-based tobacco control policy. As an alternative, the nicotine reinforcement threshold is a relatively clear concept, and well-accepted methods and criteria are available to measure nicotine reinforcement.

RESULTS

However, there are many gaps in our current knowledge concerning the nicotine reinforcement threshold in humans. The threshold for nicotine reinforcement remains to be determined in controlled settings using different populations of current or potential tobacco users. In addition, the value of the nicotine reinforcement threshold in predicting tobacco use in real-world settings needs to be examined. The results of such studies will determine the potential utility of the estimated threshold for nicotine reinforcement in developing science-based tobacco control policies.

Translational research in addiction: toward a framework for the development of novel therapeutics

The development of novel substance use disorder (SUD) therapeutics is insufficient to meet the medical needs of a growing SUD patient population. The identification of translatable SUD models and tests is a crucial step in establishing a framework for SUD therapeutic development programs. The present review begins by identifying the clinical features of SUDs and highlights the narrow regulatory end-point required for approval of a novel SUD therapeutic. A conceptual overview of dependence is provided, followed by identification of potential intervention targets in the addiction cycle. The main components of the addiction cycle provide the framework for a discussion of preclinical models and their clinical analogs, all of which are focused on isolated behavioral end-points thought to be relevant to the persistence of compulsive drug use. Thus, the greatest obstacle to successful development is the gap between the multiplicity of preclinical and early clinical end-points and the regulatory end-point of sustained abstinence. This review proposes two pathways to bridging this gap: further development and validation of the preclinical extended access self-administration model; inclusion of secondary end-points comprising all of the measures highlighted in the present discussion in Phase 3 trials. Further, completion of the postdictive validation of analogous preclinical and clinical assays is of high priority. Ultimately, demonstration of the relevance and validity of a variety of end-points to the ultimate goal of abstinence will allow researchers to identify truly relevant therapeutic mechanisms and intervention targets, and establish a framework for SUD therapeutic development that allows optimal decision-making and resource allocation.

Abuse liability assessment of tobacco products including potential reduced exposure products

The harm produced by tobacco products is a result of frequent use of a highly toxic product. Reducing the adverse public health impact of tobacco products might be most effectively achieved by reducing the likelihood of their use and the toxicity of the products. Products that retain some characteristics of cigarettes but have been altered with the intention of reducing toxicity have been referred to as modified risk tobacco products or potential reduced exposure products (MRTP/PREP). Evaluation of their content, emission, and toxicity is discussed in other articles in this special issue. Here, we discuss the methodology that has been used to examine the likelihood of abuse or addiction. Abuse liability assessment (ALA) methodology has been used by the Food and Drug Administration (FDA) and other drug regulatory agencies world-wide for decades to assess the risks posed by a wide variety of pharmacologically active substances. ALA is routinely required among other evaluations of safety during the pre-market assessment of new drugs, and is continually adapted to meet the challenges posed by new drug classes and drug formulations. In the 2009 law giving FDA regulation over tobacco products, FDA is now required to evaluate new tobacco products including MRTP/PREPs to determine their risk for abuse and toxicity at the population level. This article describes the traditional tools and methods of ALA that can be used to evaluate new tobacco and nicotine products including MRTP/PREPs. Such ALA data could contribute to the scientific foundation on which future public policy decisions are based.