Naltrexone improves quit rates, attenuates smoking urge, and reduces alcohol use in heavy drinking smokers attempting to quit smoking

Elucidating the reinforcing effects of nicotine: a tribute to Nadia Chaudhri

Nadia Chaudhri worked with us as a graduate student in the Center for Neuroscience at the University of Pittsburgh from 1999 until she earned her PhD in 2005, a time that coincided with the discovery in our lab of the dual reinforcing actions of nicotine, a concept that she played an important role in shaping. The research that was described in her doctoral thesis is among the foundational pillars of the now well-accepted notion that nicotine acts as both a primary reinforcer and an amplifier of other reinforcer stimuli. This reinforcement-enhancing action of nicotine is robust and likely to be a powerful driver of nicotine use. Below, we discuss the evidence that these two actions of nicotine - primary reinforcement and reinforcement enhancement - are distinct and dissociable, a finding that Nadia was closely associated with. We go on to address two other topics that greatly interested Nadia during that time, the generalizability of the reinforcement-enhancing action of nicotine to multiple classes of reinforcing stimuli and potential sex differences in the dual reinforcing actions of nicotine. The research has greatly expanded since Nadia's involvement, but the core ideas that she helped to develop remain central to the concept of the dual reinforcing actions of nicotine and its importance for understanding the drivers of nicotine use.

Combination treatment with varenicline and naltrexone reduces World Health Organization risk drinking levels

BACKGROUND

The U.S. Food and Drug Administration identifies abstinence and the absence of heavy drinking days as outcomes for pharmacotherapy trials for alcohol use disorder (AUD). However, many individuals with AUD struggle to achieve these outcomes, which may discourage them from seeking treatment. World Health Organization (WHO) risk drinking levels have garnered attention in the alcohol field as potential non-abstinent outcomes for AUD medication trials. Further, testing combination pharmacotherapy for AUD represents an important direction in the field, particularly using medications such as naltrexone and varenicline, which are approved for treating AUD and smoking, respectively. The objective of the current study was to test the utility of the WHO risk drinking levels as a drinking outcome in a randomized clinical trial of combined varenicline and naltrexone for smoking cessation and drinking reduction. These analyses provide additional tests of the efficacy of this combination treatment.

METHODS

The current study is a secondary analysis of a phase 2, randomized, double-blind clinical trial, wherein participants (N = 165) who were daily smokers and heavy drinkers were randomly assigned to receive either 2 mg/day of varenicline plus 50 mg/day of naltrexone or 2 mg/day of varenicline plus placebo for 12 weeks. Medication effects on 1- and 2-level reductions in WHO risk drinking levels were assessed at 4, 8, and 12 weeks into the active medication period.

RESULTS

In logistic growth curve models individuals receiving the combined treatment had greater reductions in WHO risk drinking levels than individuals taking varenicline alone when assessed at 4 weeks into the active medication period. Among individuals who were WHO high and very high risk drinkers at baseline, the largest effect sizes favoring combination treatment were at Week 4 for the WHO 2-level reduction outcome (Cohen's h = 0.202) and Week 12 for the WHO 1-level reduction outcome (Cohen's h = 0.244), although these effects did not reach statistical significance.

CONCLUSIONS

These findings provide evidence that combined varenicline plus naltrexone treatment is effective at reducing WHO risk drinking levels, particularly among individuals who smoke cigarettes daily and drink heavily. These results add to a growing body of literature validating reductions in WHO risk drinking levels as outcomes of alcohol medication trials.

The impact of adolescent nicotine exposure on alcohol use during adulthood: The role of neuropeptides

Nicotine and alcohol abuse and co-dependence represent major public health crises. Indeed, previous research has shown that the prevalence of alcoholism is higher in smokers than in non-smokers. Adolescence is a susceptible period of life for the initiation of nicotine and alcohol use and the development of nicotine-alcohol codependence. However, there is a limited number of pharmacotherapeutic agents to treat addiction to nicotine or alcohol alone. Notably, there is no effective medication to treat this comorbid disorder. This chapter aims to review the early nicotine use and its impact on subsequent alcohol abuse during adolescence and adulthood as well as the role of neuropeptides in this comorbid disorder. The preclinical and clinical findings discussed in this chapter will advance our understanding of this comorbid disorder's neurobiology and lay a foundation for developing novel pharmacotherapies to treat nicotine and alcohol codependence.

The effects of pharmacological interventions on smoking cessation in people with alcohol dependence: A systematic review and meta-analysis of nine randomized controlled trials

BACKGROUND

Pharmacotherapies are widely used for smoking cessation. However, their efficacy for people with alcohol dependence remains unclear.

OBJECTIVE

This study aimed to explore the effects of pharmacotherapies on smoking cessation for people with alcohol dependence.

METHODS

Five electronic databases were searched in January 2021 for randomized controlled trials (RCTs) reporting the use of pharmacotherapies to promote smoking cessation in people with alcohol dependence. The risk of bias was assessed using the Cochrane tool. RevMan version 5.3 was used to perform meta-analyses of the changes in smoking behaviour, and the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach was used to assess the certainty of the evidence.

RESULTS

The search identified nine RCTs involving 908 smokers with alcohol dependence; eight were published in the USA and one in Canada. The risk of bias was low in three studies and unclear in the remaining six. The meta-analysis results showed that, compared with the placebo group, Varenicline had a significant effect on short-term smoking cessation (three RCTs, odds ratio [OR] = 6.27, 95% confidence interval [CI]: [2.49, 15.78], P < .05, very low certainty). Naltrexone had no significant effect on smoking cessation in short-term or long-term observations (three RCTs, OR = 0.99, 95% CI: [0.54, 1.81], P = .97, moderate certainty), and Topiramate had no significant effects (two RCTs, OR = 1.56, 95% CI: [0.67, 3.46], P > .05, low certainty). Only one trial reported that Bupropion did not affect smoking cessation.

CONCLUSION

Varenicline may promote smoking cessation in people with alcohol dependence. However, Naltrexone, Topiramate and Bupropion have no clear effect on increasing smoking abstinence among drinkers. The small number of studies and the low certainty of evidence indicate that the results should be interpreted cautiously.

Efficacy of Combining Varenicline and Naltrexone for Smoking Cessation and Drinking Reduction: A Randomized Clinical Trial

OBJECTIVE

Pharmacological treatments that can concomitantly address cigarette smoking and heavy drinking stand to improve health care delivery for these highly prevalent co-occurring conditions. This superiority trial compared the combination of varenicline and naltrexone against varenicline alone for smoking cessation and drinking reduction among heavy-drinking smokers.

METHODS

This was a phase 2 randomized double-blind clinical trial. Participants (N=165) who were daily smokers and drank heavily received either 2 mg/day of varenicline plus 50 mg/day of naltrexone or 2 mg/day of varenicline plus matched placebo pills for 12 weeks. Primary outcomes were 7-day point prevalence of nicotine abstinence (bioverified by a breath CO reading ≤5 ppm) at the 26-week follow-up and number of drinks per drinking day during the 12-week treatment phase.

RESULTS

Smoking abstinence at week 26 was significantly higher in the varenicline plus placebo condition than in the varenicline plus naltrexone condition (N=37 [45.1%] compared with N=22 [26.5%]). For drinks per drinking day, there was a medication effect favoring the combination of varenicline and naltrexone over varenicline alone across the 12-week treatment phase, although it did not meet the significance threshold.

CONCLUSIONS

These findings suggest that smoking cessation and drinking reduction can be concomitantly targeted with pharmacotherapy and that while varenicline alone may be sufficient as a smoking cessation aid in heavy-drinking smokers, the combination of varenicline and naltrexone may confer benefits with regard to drinking outcomes, particularly during the 12-week period of active medication treatment.

Combined varenicline and naltrexone attenuates alcohol cue-elicited activation in heavy drinking smokers

BACKGROUND

There is a strong bidirectional relationship between the use of alcohol and cigarettes which results in various challenges for treating those who co-use both substances. While varenicline and naltrexone each have FDA-approval for nicotine and alcohol use disorder, respectively, there is evidence that their clinical benefit may extend across the two disorders. Critically, the effect of combined varenicline and naltrexone on neural reactivity to alcohol cues among heavy drinking smokers has not yet been studied. Probing the effect of the combination therapy on alcohol cue-reactivity may give insight to the mechanisms underlying its efficacy.

METHODS

Forty-seven heavy drinking smokers enrolled in two medication studies were randomized to receive varenicline alone (n = 11), varenicline plus naltrexone (n = 11), or placebo (n = 25). Participants completed an fMRI alcohol cue-reactivity task and rated their in-scanner alcohol craving. Whole-brain analyses examined the effect of medication on alcohol cue-elicited neural response.

RESULTS

Varenicline plus naltrexone attenuated alcohol cue-elicited activation in mesolimbic regions relative to varenicline alone and to placebo (Z > 2.3, p < 0.05). The combination varenicline and naltrexone group also endorsed lower in-scanner alcohol craving relative to varenicline alone group (p = 0.04).

CONCLUSIONS

These findings provide evidence for the benefit of combined therapy of varenicline and naltrexone over varenicline alone for the attenuation of alcohol cue-elicited neural activation. This study provides a preliminary proof-of-mechanism for this combination pharmacotherapy and suggests that naltrexone may be driving the reductions in cue-elicited alcohol craving in the brain. Further clinical studies using the combined therapy to treat heavy drinking smokers are warranted.

Targeting the Opioid Receptors: A Promising Therapeutic Avenue for Treatment in “Heavy Drinking Smokers”

Aims

Despite a general decline in tobacco use in the last decades, the prevalence of tobacco smoking in individuals with alcohol use disorder (AUD) remains substantial (45–50%). Importantly, the co-use of both substances potentiates the adverse effects, making it a significant public health problem. Substantial evidence suggests that AUD and Tobacco use disorder (TUD) may share common mechanisms. Targeting these mechanisms may therefore provide more effective therapy. Numerous studies describe a potential role of the endogenous opioid system in both AUD and TUD. Reviewing this literature, we aim to evaluate the efficacy of molecules that target the opioid system as promising therapeutic interventions for treating alcohol and tobacco co-use disorders.

Methods

We provide a synthesis of the current epidemiological knowledge of alcohol and tobacco co-use disorders. We evaluate clinical and preclinical research that focuses on the regulation of the endogenous opioid system in alcohol, nicotine, and their interactions.

Results

The epidemiological data confirm that smoking stimulates heavy drinking and facilitates alcohol craving. Pharmacological findings suggest that treatments that are efficacious in the dual addiction provide a beneficial treatment outcome in comorbid AUD and TUD. In this regard, MOP, DOP and NOP-receptor antagonists show promising results, while the findings prompt caution when considering KOP-receptor antagonists as a treatment option in alcohol and tobacco co-use disorders.

Conclusions

Existing literature suggests a role of the opioid system in sustaining the high comorbidity rates of AUD and TUD. Molecules targeting opioid receptors may therefore represent promising therapeutic interventions in ‘heavy drinking smokers.’

Effects of ethanol, naltrexone, nicotine and varenicline in an ethanol and nicotine co-use model in Sprague-Dawley rats

BACKGROUND

As alcohol and nicotine use disorders are entwined, it may be possible to develop a single medication to treat both. We previously developed a model for ethanol (EtOH) and nicotine co-use in female selectively bred alcohol-preferring (P) rats. To model co-use in a genetically diverse population, we adapted the model to outbred Sprague-Dawley rats of both sexes and assessed the effect of drug pretreatments.

METHODS

In phase 1, rats were trained in a 2-bottle choice between water and a sweetened or unsweetened EtOH solution in operant chambers. In phase 2, rats were trained in nicotine self-administration under an increasing fixed ratio (FR) schedule with 2 bottles containing water or saccharin-sweetened EtOH also available. In phase 3, rats were pretreated with EtOH (0.5, 1.5 g/kg), naltrexone (0.3 mg/kg), nicotine (0.2, 0.6 mg/kg), varenicline (3.0 mg/kg) or vehicle before the session.

RESULTS

Sweetening the EtOH solution was required to obtain pharmacologically relevant levels of consumption in Phase 1, with males showing increased sweetened EtOH preference compared to females. In Phase 2, increasing the FR requirement for nicotine decreased nicotine infusions, but increased EtOH consumption. In Phase 3, EtOH, naltrexone, and nicotine failed to alter EtOH consumption; however, varenicline decreased both EtOH and nicotine intake.

CONCLUSIONS

The co-use model was successfully adapted to Sprague-Dawley rats by adding saccharin to the EtOH solution. In contrast to previous results in P rats, varenicline reduced both EtOH and nicotine intake, indicating it may be a useful monotherapy for co-use in a genetically diverse population.

A Digital Smoking Cessation Program for Heavy Drinkers: Pilot Randomized Controlled Trial

Background

Heavy drinking (HD) is far more common among smokers compared with nonsmokers and interferes with successful smoking cessation. Alcohol-focused smoking cessation interventions delivered by counselors have shown promise, but digital versions of these interventions—which could have far greater population reach—have not yet been tested.

Objective

This pilot randomized controlled trial aimed to examine the feasibility, acceptability, and effect sizes of an automated digital smoking cessation program that specifically addresses HD using an interactive web-based intervention with an optional text messaging component.

Methods

Participants (83/119, 69.7% female; 98/119, 82.4% white; mean age 38.0 years) were daily smokers recruited on the web from a free automated digital smoking cessation program (BecomeAnEX.org, EX) who met the criteria for HD: women drinking 8+ drinks/week or 4+ drinks on any day and men drinking 15+ drinks/week or 5+ drinks on any day. Participants were randomized to receive EX with standard content (EX-S) or an EX with additional content specific to HD (EX-HD). Outcomes were assessed by web-based surveys at 1 and 6 months.

Results

Participants reported high satisfaction with the website and the optional text messaging component. Total engagement with both EX-S and EX-HD was modest, with participants visiting the website a median of 2 times, and 52.9% of the participants enrolled to receive text messages. Participants in both the conditions showed substantial, significant reductions in drinking across 6 months of follow-up, with no condition effects observed. Although smoking outcomes tended to favor EX-HD, the condition effects were small and nonsignificant. A significantly smaller proportion of participants in EX-HD reported having a lapse back to smoking when drinking alcohol (7/58, 16%) compared with those in EX-S (18/61, 41%; χ²₁=6.2; P=.01).

Conclusions

This is the first trial to examine a digital smoking cessation program tailored to HD smokers. The results provide some initial evidence that delivering such a program is feasible and may reduce the risk of alcohol-involved smoking lapses. However, increasing engagement in this and other web-based interventions is a crucial challenge to address in future work.

Trial Registration

ClinicalTrials.gov NCT03068611; https://clinicaltrials.gov/ct2/show/NCT03068611

Current pharmacologic treatments for smoking cessation and new agents undergoing clinical trials

Smoking causes various diseases and is a major public health threat worldwide. Therefore, promoting smoking cessation is the most important intervention contributing to maintaining the health of smokers and nonsmokers and saving enormous financial expense. We reviewed existing and emerging smoking-cessation pharmacotherapies from the Cochrane Database of Systemic Reviews, PubMed, Ovid, and ClinicalTrials.gov databases. A literature review revealed that bupropion may be appropriate for patients interested in reducing smoking who dislike, or who have failed, nicotine-replacement therapy (NRT). Additionally, varenicline and NRT are efficacious first-line smoking cessation treatments and should be given to all individuals unless contraindicated.

The reviews of this paper are available via the supplementary material section.

Lack of Association between Opioid-Receptor Genotypes and Smoking Cessation Outcomes in a Randomized, Controlled Naltrexone Trial

AIMS

The present study examined how variation in mu- (OPRM1), kappa- (OPRK), and delta- (OPRD) opioid receptor genes may influence the efficacy of naltrexone in the context of a smoking cessation trial.

METHODS

The study's primary objective was to examine the association of the Asn40Asp OPRM1 single nucleotide polymorphism (SNP) with naltrexone's effects on smoking quit rate, weight gain, and heavy drinking behavior during a double-blind, randomized clinical trial in 280 adult DSM-IV nicotine-dependent participants. The secondary goal of the study was to examine the relationship of 20 additional SNPs of OPRM1, OPRK, and OPRD with the aforementioned outcomes.

RESULTS

Results indicated a null association between any opioid-receptor gene SNP and naltrexone's effects on smoking quit rate, weight gain, and heavy drinking behavior in this sample of nicotine dependent participants.

CONCLUSIONS

In sum, these results do not suggest that genetic variation in opioid-receptors is related to treatment responses to naltrexone in a smoking cessation trial.

Vibration of effects from diverse inclusion/exclusion criteria and analytical choices: 9216 different ways to perform an indirect comparison meta-analysis

BACKGROUND

Different methodological choices such as inclusion/exclusion criteria and analytical models can yield different results and inferences when meta-analyses are performed. We explored the range of such differences, using several methodological choices for indirect comparison meta-analyses to compare nalmefene and naltrexone in the reduction of alcohol consumption as a case study.

METHODS

All double-blind randomized controlled trials (RCTs) comparing nalmefene to naltrexone or one of these compounds to a placebo in the treatment of alcohol dependence or alcohol use disorders were considered. Two reviewers searched for published and unpublished studies in MEDLINE (August 2017), the Cochrane Library, Embase, and ClinicalTrials.gov and contacted pharmaceutical companies, the European Medicines Agency, and the Food and Drug Administration. The indirect comparison meta-analyses were performed according to different inclusion/exclusion criteria (based on medical condition, abstinence of patients before inclusion, gender, somatic and psychiatric comorbidity, psychological support, treatment administered and dose, treatment duration, outcome reported, publication status, and risk of bias) and different analytical models (fixed and random effects). The primary outcome was the vibration of effects (VoE), i.e. the range of different results of the indirect comparison between nalmefene and naltrexone. The presence of a "Janus effect" was investigated, i.e. whether the 1st and 99th percentiles in the distribution of effect sizes were in opposite directions.

RESULTS

Nine nalmefene and 51 naltrexone RCTs were included. No study provided a direct comparison between the drugs. We performed 9216 meta-analyses for the indirect comparison with a median of 16 RCTs (interquartile range = 12-21) included in each meta-analysis. The standardized effect size was negative at the 1st percentile (- 0.29, favouring nalmefene) and positive at the 99th percentile (0.29, favouring naltrexone). A total of 7.1% (425/5961) of the meta-analyses with a negative effect size and 18.9% (616/3255) of those with a positive effect size were statistically significant (p < 0.05).

CONCLUSIONS

The choice of inclusion/exclusion criteria and analytical models for meta-analysis can result in entirely opposite results. VoE evaluations could be performed when overlapping meta-analyses on the same topic yield contradictory result.

TRIAL REGISTRATION

This study was registered on October 19, 2016, in the Open Science Framework (OSF, protocol available at https://osf.io/7bq4y/ ).

Medication-enhanced behavior therapy for alcohol use disorder: Naltrexone, Alcoholics Anonymous Facilitation, and OPRM1 genetic variation

Medication-assisted behavior treatment for alcohol use disorder (AUD) holds promise to enhance the efficacy of medication and of behavior therapy when administered individually. The present study examines the treatment benefit of combined outpatient naltrexone (NTX) treatment with Alcoholics Anonymous Facilitation (AAF) behavior therapy, in the context of OPRM1 genotype. The minor OPRM1 Asp40 G-allele has been associated with greater positive reinforcing effects of alcohol consumption and greater alcohol craving, suggesting that individuals carrying the OPRM1 G allele may have an improved naltrexone response. Twenty patients, including 7 G-allele carriers, received 90 days of naltrexone with medication support and dispensing sessions, and ten AAF behavior therapy sessions. During treatment and the eight-week posttreatment follow-up, an overall increase in percent days abstinent was observed for the sample as a whole, but G-allele carriers reported relatively heavier drinking relative to other subjects. These findings suggest that this enhanced medication-assisted behavior treatment is a promising therapeutic combination, and mirror other recent findings that G-allele carriers may require more intensive treatment.

Neuroimaging findings from an experimental pharmacology trial of naltrexone in heavy drinkers of East Asian descent

BACKGROUND

Despite known genetic variation across races, studies examining pharmacogenetics of a single nucleotide polymorphism (SNP) of the mu-opioid receptor gene (OPRM1) on clinical response to naltrexone have been conducted in predominantly Caucasian samples. Evidence is mixed for pharmacogenetic OPRM1 and naltrexone effects on neural responses to alcohol cues. The current study tests the pharmacogenetic effects of naltrexone and OPRM1 on neural responses to alcohol taste cues in heavy drinkers of East Asian descent.

METHODS

Participants (N = 41) completed two double-blinded and counterbalanced functional magnetic resonance imaging (fMRI) sessions: one after taking naltrexone (50 mg/day) for four days and one after taking placebo for four days. Following titration, participants completed an fMRI alcohol taste-cues task. Analyses tested effects of naltrexone, OPRM1, and their interaction in whole-brain and region of interest (ROI) analyses of functional activation and functional connectivity in response to alcohol versus water taste cues.

RESULTS

We found no effects of naltrexone orOPRM1 on neural activation in whole-brain and ROI analyses, which included left and right ventral striatum (VS), anterior cingulate cortex (ACC), and orbitofrontal cortex (OFC). Naltrexone increased functional connectivity between left VS and clusters in medial prefrontal cortex, posterior cingulate gyrus, as well as right VS and occipital cortex, compared to placebo.

CONCLUSIONS

Naltrexone treatment enhanced functional connectivity in a key reinforcement-related pathway during alcohol versus water taste cues, corroborating neuroimaging work with other substances. Null medication and pharmacogenetics effects on functional activation add to a mixed naltrexone literature and may underscore the modest size of these effects in East Asians.

Naltrexone and alcohol effects on craving for cigarettes in heavy drinking smokers

Naltrexone has been extensively studied for the treatment of alcohol use disorder. However, less is known about the effects of naltrexone on smoking outcomes in the context of alcohol use among East Asian individuals who have been suggested to differ in response to alcohol and to naltrexone. The present study is a secondary analysis that used a double-blind placebo-controlled design (n = 31) to examine the (a) effects of alcohol on basal craving for cigarettes, (b) effects of naltrexone on cigarette craving and alcohol craving during alcohol administration, and (c) relationship between craving for alcohol and cigarettes. Heavy drinking smokers of East Asian descent completed two counterbalanced intravenous alcohol administration sessions, one after taking naltrexone (50 mg) for five days and one after taking a placebo for five days. Self-reported subjective craving for cigarettes and for alcohol was recorded during each experimental session. Craving for cigarettes and alcohol increased significantly throughout the intravenous alcohol administration. A significant breath alcohol concentration (BrAC) × Medication interaction revealed that naltrexone blunted cigarette craving during alcohol administration, compared to placebo. Naltrexone significantly reduced craving for alcohol during alcohol administration in this group of heavy drinking smokers. Alcohol craving significantly predicted cigarette craving, however this effect did not vary across rising alcohol administration or by medication. These findings demonstrate that naltrexone reduces the urge to smoke and to drink during alcohol administration. Clinical studies are needed to further ascertain whether naltrexone may be of benefit to this distinct subgroup of heavy drinking smokers. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

An improved model of ethanol and nicotine co-use in female P rats: Effects of naltrexone, varenicline, and the selective nicotinic α6β2* antagonist r-bPiDI

Background Although pharmacotherapies are available for alcohol (EtOH) or tobacco use disorders individually, it may be possible to develop a single pharmacotherapy to treat heavy drinking tobacco smokers by capitalizing on the commonalities in their mechanisms of action. Methods Female alcohol-preferring (P) rats were trained for EtOH drinking and nicotine self-administration in two phases: (1) EtOH alone (0 vs. 15% EtOH, 2-bottle choice) and (2) concomitant access, during which EtOH access continued with access to nicotine (0.03 mg/kg/infusion, i.v.) using a 2-lever choice procedure (active vs. inactive lever) in which the fixed ratio (FR) requirement was gradually increased to FR30. When stable co-use was obtained, rats were pretreated with varying doses of naltrexone, varenicline, or r-bPiDI, an α6β2* subtype-selective nicotinic acetylcholine receptor antagonist shown previously to reduce nicotine self-administration. Results While EtOH intake was initially suppressed in phase 2 (co-use), pharmacologically relevant intake for both substances was achieved by raising the "price" of nicotine to FR30. In phase 2, naltrexone decreased EtOH and water consumption but not nicotine intake; in contrast, naltrexone in phase 1 (EtOH only) did not significantly alter EtOH intake. Varenicline and r-bPiDI in phase 2 both decreased nicotine self-administration and inactive lever pressing, but neither altered EtOH or water consumption. Conclusions These results indicate that increasing the "price" of nicotine increases EtOH intake during co-use. Additionally, the efficacy of naltrexone, varenicline, and r-bPiDI was specific to either EtOH or nicotine, with no efficacy for co-use. Nevertheless, future studies on combining these treatments may reveal synergistic efficacy.

Distress Tolerance and Craving for Cigarettes Among Heavy Drinking Smokers

OBJECTIVE

Heavy drinking smokers experience significant difficulties with smoking cessation. Craving is closely tied to relapses during cessation attempts, and alcohol consumption increases cigarette craving among heavy drinking smokers. To date, however, few moderators of the relationship between craving and relapse have been identified. Individuals' capacity for distress tolerance predicts smoking cessation outcomes and may be connected to craving. Relatedly, pharmacotherapies like varenicline and naltrexone reduce cigarette and alcohol cravings, respectively. No studies have examined the interrelationships among distress tolerance, craving, and pharmacotherapy effects. This study therefore examines distress tolerance as a moderator of the relationship between overnight abstinence-induced cigarette craving and subsequent alcohol- and cigarette-induced changes in craving among heavy drinking smokers. This study also examines the impact of varenicline and naltrexone on these relationships.

METHOD

A total of 120 non-treatment-seeking heavy drinking smokers were randomized and titrated to one of the following conditions: (a) placebo, (b) varenicline, (c) naltrexone, or (d) varenicline + naltrexone. Participants then completed a laboratory paradigm after overnight abstinence that included consumption of alcohol (target .06 g/dl breath alcohol concentration) and one cigarette. Craving was assessed as abstinence-induced (Time 1), alcohol-induced (Time 2), and cigarette-induced (Time 3).

RESULTS

Within varenicline + naltrexone, low distress tolerance individuals exhibited higher increases from abstinence- to alcohol-induced cigarette craving relative to high distress tolerance individuals. Across medications, low distress tolerance individuals reported flatter decreases from abstinence- to cigarette-induced cigarette craving relative to high distress tolerance individuals.

CONCLUSIONS

Distress tolerance may differentially predict alcohol-induced cigarette craving when titrated to pharmacotherapy, as well as moderate decreases in craving after cigarette consumption. Future exploration of the identified interactive effects could elucidate specific conditions in which cravings are more proximally related to abstinence-induced smoking.

Distress Tolerance and Craving for Cigarettes Among Heavy Drinking Smokers

OBJECTIVE

Heavy drinking smokers experience significant difficulties with smoking cessation. Craving is closely tied to relapses during cessation attempts, and alcohol consumption increases cigarette craving among heavy drinking smokers. To date, however, few moderators of the relationship between craving and relapse have been identified. Individuals' capacity for distress tolerance predicts smoking cessation outcomes and may be connected to craving. Relatedly, pharmacotherapies like varenicline and naltrexone reduce cigarette and alcohol cravings, respectively. No studies have examined the interrelationships among distress tolerance, craving, and pharmacotherapy effects. This study therefore examines distress tolerance as a moderator of the relationship between overnight abstinence-induced cigarette craving and subsequent alcohol- and cigarette-induced changes in craving among heavy drinking smokers. This study also examines the impact of varenicline and naltrexone on these relationships.

METHOD

A total of 120 non-treatment-seeking heavy drinking smokers were randomized and titrated to one of the following conditions: (a) placebo, (b) varenicline, (c) naltrexone, or (d) varenicline + naltrexone. Participants then completed a laboratory paradigm after overnight abstinence that included consumption of alcohol (target .06 g/dl breath alcohol concentration) and one cigarette. Craving was assessed as abstinence-induced (Time 1), alcohol-induced (Time 2), and cigarette-induced (Time 3).

RESULTS

Within varenicline + naltrexone, low distress tolerance individuals exhibited higher increases from abstinence- to alcohol-induced cigarette craving relative to high distress tolerance individuals. Across medications, low distress tolerance individuals reported flatter decreases from abstinence- to cigarette-induced cigarette craving relative to high distress tolerance individuals.

CONCLUSIONS

Distress tolerance may differentially predict alcohol-induced cigarette craving when titrated to pharmacotherapy, as well as moderate decreases in craving after cigarette consumption. Future exploration of the identified interactive effects could elucidate specific conditions in which cravings are more proximally related to abstinence-induced smoking.

Nicotine-Use/Smoking Is Associated with the Efficacy of Naltrexone in the Treatment of Alcohol Dependence

BACKGROUND

The opioid antagonist naltrexone is not efficacious for every alcohol treatment seeker. However, various individual factors, such as genetic differences and nicotine-use/smoking status, have been suggested as predictors of naltrexone response. In a randomized clinical trial, we previously reported that nicotine-use/smoking status might be a stronger predictor of naltrexone efficacy than OPRM1 A118G single nucleotide polymorphism (SNP) genotype. In this report, we further characterize the nicotine-users in that trial, examine other drinking outcomes, examine the influence of smoking change on naltrexone effects on drinking, and validate the result in smokers with disialo carbohydrate-deficient transferrin (%dCDT) change as an independent biomarker of response.

METHODS

Individuals (n = 146) meeting DSM-IV criteria for alcohol dependence who were genotyped for the OPRM1 A118G SNP and who did, or did not, use nicotine/cigarettes were randomized, in a balanced fashion, to naltrexone (50 mg/d) or placebo and provided medical management (MM) over a 16-week clinical trial. Alcohol use and smoking during the trial were assessed and analyzed.

RESULTS

Nicotine-use/smoking status significantly interacted with medication in reducing percent heavy drinking days (PHDD) during the trial (p = 0.003), such that nicotine-users/smokers showed significantly lower PHDD on naltrexone versus placebo (p = 0.0001, Cohen's d = 0.89), while nonusers showed no significant difference between naltrexone and placebo (p = 0.95, Cohen's d = 0.02). Similar effects were shown for drinks per day and percent days drinking. The superiority of naltrexone over placebo on PHDD reduction in nicotine-users/smokers was confirmed with %dCDT (Cohen's d range 0.3 to 0.9 over the study). Naltrexone did not significantly change cigarette use in smokers, and change in use did not influence naltrexone's effect on PHDD.

CONCLUSIONS

These data confirm past findings that naltrexone is more efficacious in those who use nicotine/cigarettes. Compared to previous work on the OPRM1 A118G SNP, it appears that nicotine-use might be a more salient predictor of naltrexone treatment response. While naltrexone did not change cigarette use during the study, and smoking change was not related to alcohol reduction, it should be noted that participants were not seeking smoking cessation and MM did not address this issue.

Current and Emerging Pharmacotherapies for Cessation of Tobacco Smoking

Tobacco use disorder is a chronic illness. With its high comorbidity rate, it is a major cause of years of life lost or years lived with disability; however, it is also considered the most preventable cause of death in developed countries. Since the development of nicotine replacement therapy (NRT) in 1978, treatment options have continued to evolve and expand. Despite this, currently available treatments remain insufficient, with less than 25% of smokers remaining abstinent 1 year after treatment. In this article, we review existing and emerging smoking cessation pharmacotherapies, with a special emphasis on the most promising agents that are currently being investigated. A search of the Cochrane Database of Systematic Reviews and the PubMed, Ovid, and ClinicalTrials.gov databases (August 2 to September 1, 2017) was undertaken for articles on smoking cessation pharmacotherapies, applying no language restrictions. More than 40 pharmacotherapies were reviewed including conventional pharmacotherapies-NRT, bupropion, and varenicline (all approved by the U.S. Food and Drug Administration as first-line treatment of smoking cessation)-and novel therapies: cytisine, N-acetylcysteine, cycloserine, memantine, baclofen, topiramate, galantamine, and bromocriptine. Studies of combination NRT and varenicline showed the greatest smoking cessation rates. Clonidine and nortriptyline are second-line treatments used when first-line treatments fail or are contraindicated, or by patient preference. Some novel therapies, especially acetylcholinesterase inhibitors, cytisine, and N-acetylcysteine, display promising results. Because the results of randomized clinical trials were reported using varied end points and outcome measures, direct comparisons between different pharmacotherapies cannot easily be evaluated. Additional high-quality randomized double-blind placebo-controlled trials with long-term follow-up, using validated sustained abstinence measures, are needed to find more effective smoking cessation aids.

A Brief Smoking Cessation Intervention for Heavy Drinking Smokers: Treatment Feasibility and Acceptability

Approximately 20-25% of regular smokers report heavy drinking. Abstinent smokers are five times as likely to experience a smoking lapse during drinking episodes. Current efforts seek to improve treatments for this subgroup of heavy-drinking smokers. This study tested the feasibility and acceptability of addressing alcohol use in a brief, single session smoking cessation intervention (SMK+A) compared to smoking cessation counseling only (SMK); these interventions were grounded in a motivational interview framework and included personalized feedback, decisional balance, quit day setting, and tailored skills building (e.g., breathing techniques, coping with urges, dealing with social pressures) to maintain abstinence. Descriptive outcomes included reported helpfulness of intervention skills, readiness to change scores, and feasibility of participant recruitment and retention. We also assessed 7-day point prevalence of smoking cessation, and smoking and drinking reduction at 1-month follow-up. Participants (N = 22) were community-based treatment-seeking daily smokers (≥5 cigarettes/day) who were also heavy drinkers (≥14 drinks/week for men, ≥ 7 drinks/week for women; or ≥5 drinks on one episode in past week for men, ≥4 for women). Twenty five percent of interested individuals were eligible after initial phone screen, and all randomized participants were retained through follow up. All skills demonstrated high acceptability (i.e., rated between moderately and very helpful), and a significant proportion of participants in each condition reported taking action to reduce cigarette smoking and/or alcohol use at 1-month post-quit. Three participants in each condition (27.3%) attained bioverified (CO ≤ 4 parts per million and cotinine ≤ 3 ng/mL) smoking quit at follow-up. Given the modified intervention's acceptability and flexibility, larger studies may help to elucidate this intervention's effects on readiness to change, smoking cessation, and alcohol reduction.

Predictors of Naltrexone Response in a Randomized Trial: Reward-Related Brain Activation, OPRM1 Genotype, and Smoking Status

Naltrexone reduces drinking among individuals with alcohol use disorders (AUDs), but it is not effective for everyone. Variability in its effects on reward-related brain activation, genetic variation, and/or cigarette smoking may account for this mixed response profile. This randomized clinical trial tested the effects of naltrexone on drinking and alcohol cue-elicited brain activation, evaluated whether OPRM1 A118G genotype or smoking moderated these effects, and explored whether the effects of medication on cue-elicited activation predicted subsequent drinking. One hundred and fifty-two treatment-seeking individuals with alcohol dependence, half preselected to carry at least one A118G G (Asp) allele, were randomized to naltrexone (50 mg) or placebo for 16 weeks and administered an fMRI alcohol cue reactivity task at baseline and after 2 weeks of treatment. Naltrexone, relative to placebo, significantly reduced alcohol cue-elicited activation of the right ventral striatum (VS) between baseline and week 2 and reduced heavy drinking over 16 weeks. OPRM1 genotype did not significantly moderate these effects, but G-allele carriers who received naltrexone had an accelerated return to heavy drinking after medication was stopped. Smoking moderated the effects of medication on drinking, such that naltrexone was superior to placebo only among smokers. The degree of reduction in right VS activation between scans interacted with medication in predicting subsequent drinking, such that individuals with greater reduction in activation who received naltrexone, but not placebo, experienced the least heavy drinking during the following 14 weeks. These data replicate previous findings that naltrexone reduces heavy drinking and reward-related brain activation among treatment-seeking individuals with AUDs, and indicate that smoking and the magnitude of reduction in cue-elicited brain activation may predict treatment response.

A Descriptive Study of the Prevalence and Typology of Alcohol-Related Posts in an Online Social Network for Smoking Cessation

OBJECTIVE

Alcohol use and problem drinking are associated with smoking relapse and poor smoking-cessation success. User-generated content in online social networks for smoking cessation provides an opportunity to understand the challenges and treatment needs of smokers. This study used machine-learning text classification to identify the prevalence, sentiment, and social network correlates of alcohol-related content in the social network of a large online smoking-cessation program, BecomeAnEX.org.

METHOD

Data were analyzed from 814,258 posts (January 2012 to May 2015). Posts containing alcohol keywords were coded via supervised machine-learning text classification for information about the user's personal experience with drinking, whether the user self-identified as a problem drinker or indicated problem drinking, and negative sentiment about drinking in the context of a quit attempt (i.e., alcohol should be avoided during a quit attempt).

RESULTS

Less than 1% of posts were related to alcohol, contributed by 13% of users. Roughly a third of alcohol posts described a personal experience with drinking; very few (3%) indicated "problem drinking." The majority (70%) of alcohol posts did not express negative sentiment about drinking alcohol during a quit attempt. Users who did express negative sentiment about drinking were more centrally located within the network compared with those who did not.

CONCLUSIONS

Discussion of alcohol was rare, and most posts did not signal the need to quit or abstain from drinking during a quit attempt. Featuring expert information or highlighting discussions that are consistent with treatment guidelines may be important steps to ensure smokers are educated about drinking risks.

Optimizing follow-up and study retention in the 21st century: Advances from the front line in alcohol and tobacco research

AIMS

Longitudinal studies are integral in addiction research but retention of participants over time can be challenging. While statistical algorithms for missing data have advanced, they remain less desirable than collecting actual data with high retention rates. An update to methodological primers with consideration of evolving technology and privacy concerns is needed for 21st century researchers.

METHODS

Comprehensive follow-up methodological strategies were conducted in four concurrent laboratory- and intervention-based studies across N=697 drinker and smokers enrolled in studies at the Clinical Addictions Research Laboratory at the University of Chicago. The methods of three key longitudinal research themes and their outcomes are outlined, including: a) mindset of the research team starting at study enrollment, b) modalities with a particular focus on advances in technological strategies in follow-up, and c) mitigating difficult to reach and challenging participants.

RESULTS

The techniques described herein produced follow-up rates of 95% and 99% in two laboratory-based studies with follow-ups of 1- and 6-years, respectively and 94% and 97% in two intervention studies with follow-ups of 6- and 12- months. Adapting incentive strategies more than tripled on-time follow-up, from 18% to 68% of the sample, switching to more advanced technologies decreased participant burden and time by 30% from traditional telephone interviews, and difficult-to-reach participants averaged 47 contact attempts.

CONCLUSIONS

The methods presented produced exceptional follow-up retention across four studies. The principles and methodologies discussed may be modified across a range of studies to target various sub-populations in the addiction field.

A Double-Blind Randomized Placebo-Controlled Trial of Oral Naltrexone for Heavy-Drinking Smokers Seeking Smoking Cessation Treatment

BACKGROUND

Post hoc analyses of 2 randomized controlled trials suggest naltrexone may reduce alcohol use and improve smoking cessation outcomes among heavy drinkers receiving smoking cessation treatment. However, no studies have been conducted specifically to examine naltrexone for this purpose or to test whether naltrexone has benefit when added to smoking cessation counseling that explicitly addresses heavy drinking.

METHODS

We recruited heavy-drinking smokers from the community and randomized them to receive 10 weeks of either (i) 50 mg naltrexone (n = 75) or (ii) placebo (n = 75) daily. Participants received 6 weeks of transdermal nicotine patch and 6 sessions of counseling that addressed both heavy drinking and smoking. Participants were followed for 26 weeks after their target quit smoking date.

RESULTS

Across medication conditions, there were substantial reductions at follow-up in percent heavy drinking days (primary outcome) and average drinks per week (secondary outcome). However, participants receiving naltrexone did not differ significantly from those receiving placebo on percent heavy drinking days (effect size d = -0.04, 95% CI [-0.30, 0.22], p = 0.76) or average drinks per week (d = -0.09, 95% CI [-0.35, 0.18], p = 0.54) during follow-up. Naltrexone compared to placebo was not associated with a significant increase in smoking abstinence rates during follow-up, odds ratio = 0.93, 95% CI [0.46, 1.86], p = 0.83. The effect of naltrexone on these outcomes was not significantly moderated by current alcohol dependence or gender.

CONCLUSIONS

Results indicate that heavy-drinking smokers, including those with current alcohol dependence, can make substantial reductions in drinking in the context of smoking cessation treatment. However, this study provided no evidence that naltrexone is efficacious for enhancing reductions in drinking or improving smoking cessation in this population. Limitations of this study included lower-than-desired sample size and modest adherence to study medication.

Nociceptin/orphanin FQ receptor gene variation is associated with smoking status in Japanese

Aim: The endogenous opioid system has been reportedly implicated in tobacco/nicotine dependence. Materials & methods: We examined the genetic effects of eight SNPs in opioid receptor-related genes on smoking status and smoking-related traits in Japanese. Results: The genotypic and allelic variations of the rs2229205 SNP in the OPRL1 gene were significantly associated with smoking status, but no significant differences were found in the genetic variations of any of the SNPs with regard to smoking-related traits. The rs2229205 SNP did not show high linkage disequilibrium with the other SNPs in the linkage disequilibrium block that contained the SNP. Conclusion: The rs2229205 SNP in the OPRL1 gene may be a genetic factor that contributes to individual differences in the vulnerability to smoking in Japanese individuals.

A gene-by-sex interaction for nicotine reward: evidence from humanized mice and epidemiology

It has been proposed that vulnerability to nicotine addiction is moderated by variation at the μ-opioid receptor locus (OPRM1), but results from human studies vary and prospective studies based on genotype are lacking. We have developed a humanized mouse model of the most common functional OPRM1 polymorphism rs1799971_A>G (A118G). Here we use this model system together with a cohort of German youth to examine the role of the OPRM1 A118G variation on nicotine reward. Nicotine reinforcement was examined in the humanized mouse model using i.v. self-administration. Male (n=17) and female (n=26) mice homozygous either for the major human A allele (AA) or the minor G allele (GG) underwent eight daily 2 h sessions of nicotine self-administration. Furthermore, male (n=104) and female (n=118) subjects homozygous for the A allele or carrying the G allele from the Mannheim Study of Children at Risk were evaluated for pleasurable and unpleasant experiences during their initial smoking experience. A significant sex-by-genotype effect was observed for nicotine self-administration. Male 118GG mice demonstrated higher nicotine intake than male 118AA mice, suggesting increased nicotine reinforcement. In contrast, there was no genotype effect in female mice. Human male G allele carriers reported increased pleasurable effects from their first smoking experience, as compared to male homozygous A, female G and female homozygous A allele carriers. The 118G allele appears to confer greater sensitivity to nicotine reinforcement in males, but not females.

Do Alcohol Misuse, Smoking, and Depression Vary Concordantly or Sequentially? A Longitudinal Study of HIV-Infected and Matched Uninfected Veterans in Care

We analyzed temporal patterns of alcohol misuse, smoking, and depression among veterans in care to determine whether these conditions vary concordantly or sequentially. Using the Veterans Aging Cohort Study, harmful alcohol use (AUDIT-C ≥ 4), current smoking, and depression (PHQ-9 ≥ 8), were measured. In regression analyses, predictors included each outcome condition at baseline, the other two conditions in the same survey, the other two conditions in the immediately preceding survey, number of years since enrollment, and HIV status. We found that current smoking and depression were more common among HIV infected individuals. Harmful alcohol use was more common among uninfected individuals. Temporal analyses suggested a concurrent pattern: each condition was associated with the other two conditions (p < 0.03, OR 1.12-1.66) as well as with the prior presence of the same condition (p < 0.0001; OR 6.38-22.02). Smoking was associated with prior depression after controlling for current depression (OR 1.16; p = 0.003). In conclusion, alcohol misuse, smoking, and depression were temporally concordant and persistent, raising the question of whether they constitute a common syndrome in HIV infected patients and others with chronic diseases.

Current insights into the mechanisms and development of treatments for heavy drinking cigarette smokers

There is a strong association between cigarette smoking and alcohol use at the epidemiological, behavioral, and molecular levels, and this co-use creates substantial impediments to smoking cessation among smokers who are also heavy drinkers. Compared with individuals who only smoke, those who both drink and smoke heavily experience more severe health consequences and have greater difficulty in quitting smoking. During smoking abstinence, greater alcohol use is associated with decreased odds of smoking cessation, and smokers are substantially more likely to experience a smoking lapse during drinking episodes. As heavy drinking smokers are less responsive to the currently available pharmacological treatments, this subgroup of high-risk substance users possesses a unique clinical profile and treatment needs. Thus, treatment development for heavy drinking smokers represents a significant and understudied research area within the field of smoking cessation. This review will briefly describe findings from epidemiological, behavioral, and molecular studies illustrating alcohol and tobacco co-use and identify how the behavioral and neurobiological mechanisms underlying the interaction of alcohol and nicotine may inform the development of targeted treatments for this unique population of smokers.

Combined varenicline and naltrexone treatment reduces smoking topography intensity in heavy-drinking smokers

Heavy drinking smokers constitute a distinct sub-population of smokers for whom traditional smoking cessation therapies may not be effective. Recent evidence suggested that combined varenicline (VAR) and naltrexone (NTX) therapy may be more efficacious than either monotherapy alone in reducing smoking and drinking-related behavior in this population. The manner in which individuals smoke a cigarette (i.e., smoking topography) may be predictive of smoking cessation outcomes, yet the effects of smoking pharmacotherapies on puffing behavior have not been thoroughly examined. Therefore, the current double-blind medication study examined the effects of VAR alone (1mg BID), low dose NTX alone (25mg QD), the combination of VAR+NTX, and placebo on smoking topography measures in heavy drinking, non-treatment seeking daily smokers (n=120). After a 9-day titration period, participants completed a laboratory session in which they smoked their first cigarette of the day using a smoking topography device following 12h of nicotine abstinence and consumption of an alcoholic beverage (BrAC=0.06g/dl). The primary measures were puff count, volume, duration, and velocity and inter-puff interval (IPI). Independent of medication group, puff velocity and IPI increased, while puff volume and duration decreased, over the course of the cigarette. The active medication groups, vs. the placebo group, had significantly blunted puff duration and velocity slopes over the course of the cigarette, and this effect was particularly evident in the VAR+NTX group. Additionally, the VAR+NTX group demonstrated lower average IPI than the monotherapy groups and lower average puff volume than all other groups. These results suggest that smoking pharmacotherapies, particularly the combination of VAR+NTX, alter smoking topography in heavy drinking smokers, producing a pattern of less intense puffing behavior. As smoking topography has been predictive of the ability to quit smoking, future studies should examine how smoking pharmacotherapies' effects on puffing behavior relate to smoking cessation outcomes.