Opioid antagonists for smoking cessation

Impact of the Ottawa model on opiate screening and smoking cessation in methadone-treated patients with opioid use disorder: A retrospective cohort analysis

INTRODUCTION

Approximately 60 million individuals worldwide used opioids in 2021, constituting 1.2% of the global adult population. This study aimed to evaluate the effectiveness of integrated treatment strategies for opioid use disorder and nicotine use disorder by assessing the impact of smoking cessation within a methadone treatment framework.

METHODS

In a retrospective cohort study, 53 methadone maintenance patients were divided into 16 treatment-seeking smokers (TSS) and 37 treatment-rejecting smokers (TRS) based on their participation in the Ottawa model for smoking cessation plus 16 weeks of varenicline treatment. Both groups received standard methadone treatment for 68 weeks. TSS were followed up for 44 weeks to assess smoking cessation outcomes, while TRS had none due to their lack of participation in smoking cessation treatment.

RESULTS

The median age of the TSS group was 48 years, while that of the TRS group was 45.5 years. Males comprised 75% of TSS and 94.6% of the TRS. TSS exhibited an 83% decrease in positive opioid screen results compared to TRS (p=0.023). In TSS, peak smoking cessation success was observed at week 20, with 57% of participants maintaining carbon monoxide levels <5 ppm.

CONCLUSIONS

The significant reduction in positive opioid screens and the high smoking cessation rate in the TSS group highlight the efficacy of combined treatment methods. This study underscores the advantages of integrating smoking cessation with methadone maintenance treatment, indicating that comprehensive approaches can substantially improve treatment outcomes.

Neurological Effects of Combining Low Toxic Dose of Tramadol and Nicotine: An Animal Model Evidence of Endoplasmic Reticulum Stress

Tramadol abuse is a common problem in the Middle East in conjunction with smoking. The current study applied immunohistochemistry, western blot, real-time PCR, and ELISA to test the combination toxicity. Low toxic doses of tramadol induced animal brain cortex inflammation and hippocampus injury. Adding nicotine reverted hippocampus pathological changes without triggering marked brain injury. The expression of CHOP protein with real-time PCR showed mild endoplasmic reticulum stress (ER) in rat's brain. Histological, immunohistochemical, and western blotting analysis of CHOP (CCAAT-enhancer-binding protein homologous protein) and BIP (immunoglobulin heavy chain-binding protein) chaperones demonstrated endoplasmic reticulum stress in the brains of animals. Furthermore, the levels of apoptosis and autophagy markers demonstrated a mild reaction. The blood level of serotonin was high in all study groups, with a marked increase in the combined one. The high serotonin levels in the blood can be critical and associated with a high risk of serious withdrawal and pathological consequences. Serotonin receptor blockers such as olanzapine may increase systemic serotonin levels and need further investigation to utterly pinpoint their roles in managing mood disorders. In conclusion, the combination of tramadol and nicotine is less harmful than expected. However, serious withdrawal effects can occur as a result of high systemic serotonin effects.

Spirometry and Smoking Cessation in Primary Care: The ESPIROTAB STUDY, A Randomized Clinical Trial

This study aims to evaluate the effect of regularly reporting spirometry results during smoking cessation counseling from a primary care physician on the quit rate in adult smokers.

METHODS

A randomized, two-arm intervention study was conducted at six primary care centers. A total of 350 smokers, ≥18 years of age, who consulted their primary care physician, participated in the study. At the selection visit, smokers who gave their consent to participate underwent spirometry. Subsequently, an appointment (visit 0) was scheduled to complete a nicotine dependence test, a smoking cessation motivation questionnaire, and a sociodemographic questionnaire. Participants were also offered brief, structured advice on how to quit smoking, as well as detailed information on spirometry results. Patients were then randomized and scheduled for follow-up visits at 3, 6, 12, and 24 months. Both arms received brief, structured advice and detailed information on spirometry results at visit 0. At consecutive follow-up visits, the control group only received brief, structured smoking cessation advice, while the intervention group also received information on initial spirometry results at visits 3 and 6, and a spirometry retest at visit 12. Exhaled carbon monoxide testing was used to check smoking cessation.

RESULTS

The study included 350 smokers; 179 were assigned to the control group and 171 to the intervention group. Smoking cessation at one year was 24.0% in the intervention group compared to 16.2% in the control group. At two years, it was 25.2% in the intervention group and 18.4% in the control group. Overall, the adjusted odds of quitting smoking in the intervention group were 42% higher than in the control group (p = 0.018).

CONCLUSIONS

Regular and detailed feedback of spirometry results with smokers increases smoking cessation. Specifically, the likelihood of quitting smoking in the intervention group is 1.42 times higher than in the control group (p = 0.018).

F, Deng X, Wang Y, Wang Z, Wu Y, Xu M, Yang C, Li X, Yang K. Pharmacological interventions on smoking cessation: A systematic review and network meta-analysis

Objective: A network meta-analysis based on randomized controlled trials was conducted to investigate the effects of pharmacological interventions on smoking cessation.

Methods: English databases were searched to obtain randomized controlled trials reporting the effect of pharmacological interventions on smoking cessation. The risk of bias for the included trials was assessed using Cochrane Handbook tool. Stata 15.1 software was used to perform network meta-analysis, and GRADE approach was used to assess the evidence credibility on the effects of different interventions on smoking cessation.

Results: A total of 159 studies involving 60,285 smokers were included in the network meta-analysis. The analysis involved 15 interventions and which yielded 105 pairs of comparisons. Network meta-analysis showed that varenicline was more helpful for smoking cessation than other monotherapies, such as nicotine replacement therapy [Odds Ratio (OR) = 1.42, 95% confidence interval (CI) (1.16, 1.73)] and bupropion [OR = 1.52, 95% CI (1.22, 1.89)]. Furthermore, combined interventions were superior to monotherapy in achieving smoking cessation, such as varenicline plus bupropion over bupropion [OR = 2.00, 95% CI (1.11, 3.61)], varenicline plus nicotine replacement therapy over nicotine replacement therapy [OR = 1.84, 95% CI (1.07, 3.18)], and nicotine replacement therapy plus mecamylamine over naltrexone [OR = 6.29, 95% CI (1.59, 24.90)]. Finally, the surface under the cumulative ranking curve value indicated that nicotine replacement therapy plus mecamylamine had the greatest probability of becoming the best intervention.

Conclusion: Most pharmacological interventions demonstrated a benefit in smoking cessation compared with placebo, whether monotherapy or combination therapy. Moreover, confirmed evidence suggested that some combination treatments, such as varenicline plus bupropion and nicotine replacement therapy plus mecamylamine have a higher probability of being the best smoking cessation in

The Potential of Methocinnamox as a Future Treatment for Opioid Use Disorder: A Narrative Review

The opioid epidemic is an ongoing public health crisis, and the United States health system is overwhelmed with increasing numbers of opioid-related overdoses. Methocinnamox (MCAM) is a novel mu opioid receptor antagonist with an extended duration of action. MCAM has potential to reduce the burden of the opioid epidemic by being used as an overdose rescue treatment and a long-term treatment for opioid use disorder (OUD). The currently available treatments for OUD include naloxone, naltrexone, and methadone. These treatments have certain limitations, which include short duration of action, patient non-compliance, and diversion. A narrative review was conducted using PubMed and Google Scholar databases covering the history of the opioid epidemic, pain receptors, current OUD treatments and the novel drug MCAM. MCAM could potentially be used as both a rescue and long-term treatment for opioid misuse. This is due to its pseudo-irreversible antagonism of the mu opioid receptor, abnormally long duration of action of nearly two weeks, and the possibility of using kappa or delta opioid receptor agonists for pain management during OUD treatment. MCAM’s novel pharmacokinetic and pharmacodynamic properties open a new avenue for treating opioid misuse.

Tobacco and nicotine use

Tobacco smoking is a major determinant of preventable morbidity and mortality worldwide. More than a billion people smoke, and without major increases in cessation, at least half will die prematurely from tobacco-related complications. In addition, people who smoke have a significant reduction in their quality of life. Neurobiological findings have identified the mechanisms by which nicotine in tobacco affects the brain reward system and causes addiction. These brain changes contribute to the maintenance of nicotine or tobacco use despite knowledge of its negative consequences, a hallmark of addiction. Effective approaches to screen, prevent and treat tobacco use can be widely implemented to limit tobacco's effect on individuals and society. The effectiveness of psychosocial and pharmacological interventions in helping people quit smoking has been demonstrated. As the majority of people who smoke ultimately relapse, it is important to enhance the reach of available interventions and to continue to develop novel interventions. These efforts associated with innovative policy regulations (aimed at reducing nicotine content or eliminating tobacco products) have the potential to reduce the prevalence of tobacco and nicotine use and their enormous adverse impact on population health.

Inequity in smoking cessation clinical trials testing pharmacotherapies: exclusion of smokers with mental health disorders

OBJECTIVES

People suffering from mental health disorder (MHDs) are often under-represented in clinical research though the reasons for their exclusion are rarely recorded. As they have higher rates of smoking and nicotine dependence, it is crucial that they are adequately represented in clinical trials of established pharmacotherapy interventions for smoking cessation. This review aims to examine the practice of excluding smokers with MHDs and reasons for such exclusion in clinical trials evaluating pharmacotherapy treatments for smoking cessation.

DATA SOURCE

The Cochrane database of systematic reviews was searched until September 2020 for reviews on smoking cessation using pharmacotherapies.

STUDY SELECTION

Randomised controlled trials (RCTs) within the selected Cochrane reviews were included.

DATA EXTRACTION

Conducted by one author and independently verified by three authors.

DATA SYNTHESIS

We included 279 RCTs from 13 Cochrane reviews. Of all studies, 51 (18.3%) explicitly excluded participants with any MHDs, 152 (54.5%) conditionally excluded based on certain MHD criteria and 76 (27.2%) provided insufficient information to ascertain either inclusion or exclusion. Studies of antidepressant medications used for smoking cessation were found to be 3.33 times more likely (95% CI 1.38 to 8.01, p=0.007) to conditionally exclude smokers with MHDs than explicitly exclude compared with studies of nicotine replacement therapy.

CONCLUSION

Smokers with MHDs are not sufficiently represented in RCTs examining the safety and effectiveness of smoking cessation medications. Greater access to clinical trial participation needs to be facilitated for this group to better address access to appropriate pharmacotherapeutic interventions in this vulnerable population.

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 Varenicline Alone and in Combination With Low-dose Naltrexone on Alcohol-primed Smoking in Heavy-drinking Tobacco Users: A Preliminary Laboratory Study

OBJECTIVES

Heavy-drinking tobacco users are less likely to successfully quit smoking than their moderate-drinking counterparts, even when they are prescribed smoking cessation medication. One strategy for improving treatment outcomes in this subgroup of tobacco users may be to combine medication therapies to target both alcohol and tobacco use simultaneously. Adding naltrexone to frontline smoking cessation treatments may improve treatment outcomes in this group.

METHOD

This double-blind, placebo-controlled human laboratory study examined the effects of varenicline (2 mg/d) and varenicline (2 mg/d), combined with a low dose of naltrexone (25 mg/d) on alcohol-primed smoking behavior in a laboratory model of smoking relapse in heavy-drinking tobacco users (n = 30). Participants attended a laboratory session and received an alcohol challenge (target breath alcohol concentration = 0.030 g/dL). They completed a smoking delay task that assessed their ability to resist smoking followed by an ad libitum smoking phase (primary outcomes). They also provided ratings of subjective drug effects and craving, and carbon monoxide levels were measured after smoking (secondary outcomes).

RESULTS

Participants receiving varenicline monotherapy delayed smoking longer and smoked fewer cigarettes than those on placebo. Participants receiving varenicline + low-dose naltrexone did not delay smoking longer than those receiving varenicline alone. Participants in both active medication arms smoked fewer cigarettes ad libitum than those receiving placebo.

CONCLUSIONS

Varenicline can improve smoking outcomes even after an alcohol prime, supporting its use in heavy drinkers who wish to quit smoking. Findings did not support increased efficacy of combined varenicline + low-dose naltrexone relative to varenicline monotherapy.

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).

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.

Mechanisms and Clinical Features of Co-occurring Opioid and Nicotine Use

Purpose of review

To review the literature addressing shared pathophysiological and clinical features of opioid and nicotine use to inform etiology and treatment, and highlight areas for future research.

Recent findings

Opioid and nicotine use co-occur at an alarmingly high rate, and this may be driven in part by interactions between the opioid and cholinergic systems underlying drug reward and the transition to dependence. Pain, among other shared risk factors, is strongly implicated in both opioid and nicotine use and appears to play an important role in their co-occurrence. Additionally, there are important sex/gender considerations that require further study. Regarding treatment, smoking cessation can improve treatment outcomes in opioid use disorder, and pharmacological approaches that target the opioid and cholinergic systems may be effective for treating both classes of substance use disorders.

Summary

Understanding overlapping etiological and pathophysiological mechanisms of opioid and nicotine use can aid in understanding their co-occurrence and guiding their treatment.

Endogenous opioid system: a promising target for future smoking cessation medications

BACKGROUND

Nicotine addiction continues to be a health challenge across the world. Despite several approved medications, smokers continue to relapse. Several human and animal studies have evaluated the role of the endogenous opioid system as a potential target for smoking cessation medications.

METHODS

In this review, studies that have elucidated the role of the mu (MORs), delta (DORs), and kappa (KORs) opioid receptors in nicotine reward, nicotine withdrawal, and reinstatement of nicotine seeking will be discussed. Additionally, the review will discuss discrepancies in the literature and therapeutic potential of the endogenous opioid system, and suggest studies to address gaps in knowledge with respect to the role of the opioid receptors in nicotine dependence.

RESULTS

Data available till date suggest that blockade of the MORs and DORs decreased the rewarding effects of nicotine, while activation of the MORs and DORs decreased nicotine withdrawal-induced aversive effects. In contrast, activation of the KORs decreased the rewarding effects of nicotine, while blockade of the KORs decreased nicotine withdrawal-induced aversive effects. Interestingly, blockade of the MORs and KORs attenuated reinstatement of nicotine seeking. In humans, MOR antagonists have shown benefits in select subpopulations of smokers and further investigation is required to realize their full therapeutic potential.

CONCLUSION

Future work must assess the influence of polymorphisms in opioid receptor-linked genes in nicotine dependence, which will help in both identifying individuals vulnerable to nicotine addiction and the development of opioid-based smoking cessation medications. Overall, the endogenous opioid system continues to be a promising target for future smoking cessation medications.

Psychosocial interventions for supporting women to stop smoking in pregnancy

BACKGROUND

Tobacco smoking remains one of the few preventable factors associated with complications in pregnancy, and has serious long-term implications for women and babies. Smoking in pregnancy is decreasing in high-income countries, but is strongly associated with poverty and is increasing in low- to middle-income countries.

OBJECTIVES

To assess the effects of smoking cessation interventions during pregnancy on smoking behaviour and perinatal health outcomes.

SEARCH METHODS

In this sixth update, we searched the Cochrane Pregnancy and Childbirth Group's Trials Register (13 November 2015), checked reference lists of retrieved studies and contacted trial authors.

SELECTION CRITERIA

Randomised controlled trials, cluster-randomised trials, and quasi-randomised controlled trials of psychosocial smoking cessation interventions during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and trial quality, and extracted data. Direct comparisons were conducted in RevMan, with meta-regression conducted in STATA 14.

MAIN RESULTS

The overall quality of evidence was moderate to high, with reductions in confidence due to imprecision and heterogeneity for some outcomes. One hundred and two trials with 120 intervention arms (studies) were included, with 88 trials (involving over 28,000 women) providing data on smoking abstinence in late pregnancy. Interventions were categorised as counselling, health education, feedback, incentives, social support, exercise and dissemination.In separate comparisons, there is high-quality evidence that counselling increased smoking cessation in late pregnancy compared with usual care (30 studies; average risk ratio (RR) 1.44, 95% confidence interval (CI) 1.19 to 1.73) and less intensive interventions (18 studies; average RR 1.25, 95% CI 1.07 to 1.47). There was uncertainty whether counselling increased the chance of smoking cessation when provided as one component of a broader maternal health intervention or comparing one type of counselling with another. In studies comparing counselling and usual care (largest comparison), it was unclear whether interventions prevented smoking relapse among women who had stopped smoking spontaneously in early pregnancy. However, a clear effect was seen in smoking abstinence at zero to five months postpartum (11 studies; average RR 1.59, 95% CI 1.26 to 2.01) and 12 to 17 months (two studies, average RR 2.20, 95% CI 1.23 to 3.96), with a borderline effect at six to 11 months (six studies; average RR 1.33, 95% CI 1.00 to 1.77). In other comparisons, the effect was unclear for most secondary outcomes, but sample sizes were small.Evidence suggests a borderline effect of health education compared with usual care (five studies; average RR 1.59, 95% CI 0.99 to 2.55), but the quality was downgraded to moderate as the effect was unclear when compared with less intensive interventions (four studies; average RR 1.20, 95% CI 0.85 to 1.70), alternative interventions (one study; RR 1.88, 95% CI 0.19 to 18.60), or when smoking cessation health education was provided as one component of a broader maternal health intervention.There was evidence feedback increased smoking cessation when compared with usual care and provided in conjunction with other strategies, such as counselling (average RR 4.39, 95% CI 1.89 to 10.21), but the confidence in the quality of evidence was downgraded to moderate as this was based on only two studies and the effect was uncertain when feedback was compared to less intensive interventions (three studies; average RR 1.29, 95% CI 0.75 to 2.20).High-quality evidence suggests incentive-based interventions are effective when compared with an alternative (non-contingent incentive) intervention (four studies; RR 2.36, 95% CI 1.36 to 4.09). However pooled effects were not calculable for comparisons with usual care or less intensive interventions (substantial heterogeneity, I2 = 93%).High-quality evidence suggests the effect is unclear in social support interventions provided by peers (six studies; average RR 1.42, 95% CI 0.98 to 2.07), in a single trial of support provided by partners, or when social support for smoking cessation was provided as part of a broader intervention to improve maternal health.The effect was unclear in single interventions of exercise compared to usual care (RR 1.20, 95% CI 0.72 to 2.01) and dissemination of counselling (RR 1.63, 95% CI 0.62 to 4.32).Importantly, high-quality evidence from pooled results demonstrated that women who received psychosocial interventions had a 17% reduction in infants born with low birthweight, a significantly higher mean birthweight (mean difference (MD) 55.60 g, 95% CI 29.82 to 81.38 g higher) and a 22% reduction in neonatal intensive care admissions. However the difference in preterm births and stillbirths was unclear. There did not appear to be adverse psychological effects from the interventions.The intensity of support women received in both the intervention and comparison groups has increased over time, with higher-intensity interventions more likely to have higher-intensity comparisons, potentially explaining why no clear differences were seen with increasing intervention intensity in meta-regression analyses. Among meta-regression analyses: studies classified as having 'unclear' implementation and unequal baseline characteristics were less effective than other studies. There was no clear difference between trials implemented by researchers (efficacy studies), and those implemented by routine pregnancy staff (effectiveness studies), however there was uncertainty in the effectiveness of counselling in four dissemination trials where the focus on the intervention was at an organisational level. The pooled effects were similar in interventions provided for women classified as having predominantly low socio-economic status, compared to other women. The effect was significant in interventions among women from ethnic minority groups; however not among indigenous women. There were similar effect sizes in trials with biochemically validated smoking abstinence and those with self-reported abstinence. It was unclear whether incorporating use of self-help manuals or telephone support increased the effectiveness of interventions.

AUTHORS' CONCLUSIONS

Psychosocial interventions to support women to stop smoking in pregnancy can increase the proportion of women who stop smoking in late pregnancy and the proportion of infants born low birthweight. Counselling, feedback and incentives appear to be effective, however the characteristics and context of the interventions should be carefully considered. The effect of health education and social support is less clear. New trials have been published during the preparation of this review and will be included in the next update.

New Pharmacological Agents to Aid Smoking Cessation and Tobacco Harm Reduction: What Has Been Investigated, and What Is in the Pipeline?

A wide range of support is available to help smokers to quit and to aid attempts at harm reduction, including three first-line smoking cessation medications: nicotine replacement therapy, varenicline and bupropion. Despite the efficacy of these, there is a continual need to diversify the range of medications so that the needs of tobacco users are met. This paper compares the first-line smoking cessation medications with (1) two variants of these existing products: new galenic formulations of varenicline and novel nicotine delivery devices; and (2) 24 alternative products: cytisine (novel outside Central and Eastern Europe), nortriptyline, other tricyclic antidepressants, electronic cigarettes, clonidine (an anxiolytic), other anxiolytics (e.g. buspirone), selective serotonin reuptake inhibitors, supplements (e.g. St John's wort), silver acetate, Nicobrevin, modafinil, venlafaxine, monoamine oxidase inhibitors (MAOIs), opioid antagonists, nicotinic acetylcholine receptor (nAChR) antagonists, glucose tablets, selective cannabinoid type 1 receptor antagonists, nicotine vaccines, drugs that affect gamma-aminobutyric acid (GABA) transmission, drugs that affect N-methyl-D-aspartate (NMDA) receptors, dopamine agonists (e.g. levodopa), pioglitazone (Actos; OMS405), noradrenaline reuptake inhibitors and the weight management drug lorcaserin. Six 'ESCUSE' criteria-relative efficacy, relative safety, relative cost, relative use (overall impact of effective medication use), relative scope (ability to serve new groups of patients) and relative ease of use-are used. Many of these products are in the early stages of clinical trials; however, cytisine looks most promising in having established efficacy and safety with low cost. Electronic cigarettes have become very popular, appear to be efficacious and are safer than smoking, but issues of continued dependence and possible harms need to be considered.

Clinical Laboratory Evaluation of Electronic Cigarettes/Electronic Nicotine Delivery Systems: Methodological Challenges

OBJECTIVE

Evaluating electronic cigarettes (ECIGs) in the clinical laboratory is critical to understanding their effects. However, laboratory evaluation of ECIGs can be challenging, as they are a novel, varied, and evolving class of products. The objective of this paper is to describe some methodological challenges to the clinical laboratory evaluation of ECIGs.

METHODS

The authors gathered information about challenges involved in the laboratory evaluation of ECIGs. Challenges were categorized and solutions provided when possible.

RESULTS

Methods used to study combustible cigarettes may need to be adapted to account for ECIG novelty and differences within the class. Challenges to ECIG evaluation can include issues related to 1) identification of ECIG devices and liquids, 2) determination of short -term ECIG abstinence, 3) measurement of use behavior, and 4) assessment of dependence. These challenges are discussed, and some suggestions to inform ECIG evaluation using clinical laboratory methods are provided.

CONCLUSIONS

Awareness of challenges and developing, validating, and reporting methods used to address them aids interpretation of results and replication efforts, thus enhancing the rigor of science used to protect public health through appropriate, empirically-based, ECIG regulation.

An assessment of factors associated with quality of randomized controlled trials for smoking cessation

To reduce smoking-related diseases, a research priority is to develop effective interventions for smoking cessation, and evidence from randomized controlled trials (RCTs) is usually considered to be the most valid. However, findings from RCTs may still be misleading due to methodological flaws. This study aims to assess the quality of 1083 RCTs of smoking cessation interventions in 41 relevant Cochrane Systematic Reviews (CSRs). Logistic regression analysis was performed to identify significant variables associated with the quality of RCTs. It was found that evidence for smoking cessation from RCTs was predominantly from high income countries, and the overall quality was high in only 8.6% of the RCTs. High quality RCTs tended to have a larger sample size, to be more recently published, and conducted in multiple countries belonging to different income categories. In conclusion, the overall quality of RCTs of smoking cessation interventions is far from perfect, and more RCTs in less developed countries are required to generate high grade evidence for global tobacco control. Collaboration between researchers in developed and less developed countries should be encouraged.

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.

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.

Critical needs in drug discovery for cessation of alcohol and nicotine polysubstance abuse

Polysubstance abuse of alcohol and nicotine has been overlooked in our understanding of the neurobiology of addiction and especially in the development of novel therapeutics for its treatment. Estimates show that as many as 92% of people with alcohol use disorders also smoke tobacco. The health risks associated with both excessive alcohol consumption and tobacco smoking create an urgent biomedical need for the discovery of effective cessation treatments, as opposed to current approaches that attempt to independently treat each abused agent. The lack of treatment approaches for alcohol and nicotine abuse/dependence mirrors a similar lack of research in the neurobiology of polysubstance abuse. This review discusses three critical needs in medications development for alcohol and nicotine co-abuse: (1) the need for a better understanding of the clinical condition (i.e. alcohol and nicotine polysubstance abuse), (2) the need to better understand how these drugs interact in order to identify new targets for therapeutic development and (3) the need for animal models that better mimic this human condition. Current and emerging treatments available for the cessation of each drug and their mechanisms of action are discussed within this context followed by what is known about the pharmacological interactions of alcohol and nicotine. Much has been and will continue to be gained from studying comorbid alcohol and nicotine exposure.

The opioid receptors as targets for drug abuse medication

The endogenous opioid system is largely expressed in the brain, and both endogenous opioid peptides and receptors are present in areas associated with reward and motivation. It is well known that this endogenous system plays a key role in many aspects of addictive behaviours. The present review summarizes the modifications of the opioid system induced by chronic treatment with drugs of abuse reported in preclinical and clinical studies, as well as the action of opioid antagonists and agonists on the reinforcing effects of drugs of abuse, with therapeutic perspectives. We have focused on the effects of chronic psychostimulants, alcohol and nicotine exposure. Taken together, the changes in both opioid peptides and opioid receptors in different brain structures following acute or chronic exposure to these drugs of abuse clearly identify the opioid system as a potential target for the development of effective pharmacotherapy for the treatment of addiction and the prevention of relapse.

Nicotine and health

Nicotine, an alkaloid derived from the leaves of tobacco plants (Nicotiana tabacum and Nicotiana rustica) is the primary addictive agent in tobacco products.(1,2) There are different ways of administering the various products including smoking cigarettes, chewing tobacco, holding moist snuff in the mouth, inhaling dry snuff through the nose, inhaling smoke from a waterpipe and inhaling vapour from an electronic cigarette.(3-6) It can be difficult differentiating the effects of nicotine from the many other toxic substances these products also contain. Here we review the pharmacological effects of nicotine but we will not review the well-known harmful effects of cigarettes, where it is primarily the toxins and carcinogens in tobacco smoke rather than the nicotine that cause illness and death.(7) A future article will consider the use of electronic cigarettes.

Pharmacological Options for Smoking Cessation in Heavy-Drinking Smokers

There is a high prevalence of comorbid tobacco use and alcohol use disorder (AUD), affecting more than 6 million people in the US. Globally, tobacco and alcohol use rank fourth and fifth, respectively, for disability-adjusted life-years lost. Levels of alcohol use are higher in smokers than nonsmokers, and the prevalence of smoking is higher in heavy drinkers compared with nondrinkers. This relationship is driven by many different factors, including genetics, neurobiological mechanisms, conditioning processes, and psychosocial influences. Although this unique population tends to experience more negative health consequences, more severe AUD, and poorer response to treatment than those with either AUD or tobacco use disorder alone, there are currently no available treatment protocols tailored to this comorbid condition. In this review, we provide a comprehensive review of ongoing clinical research into smoking cessation options for heavy-drinking smokers (HDS) through an evaluation of the effect of promising novel pharmacotherapies as well as combination therapies, including varenicline, naltrexone, the combination of varenicline and naltrexone, and the combination of naltrexone and nicotine replacement therapy (NRT). These treatments are considered in light of the standard of care for smoking cessation, and seek to improve upon the available guidelines for this sizeable subgroup of smokers, namely those smokers who drink heavily.

Acute effects of low and high dose alcohol on smoking lapse behavior in a laboratory analogue task

RATIONALE

Smoking lapses (i.e., returns to smoking after quitting) often occur following alcohol consumption with observational data suggesting greater quantities of alcohol lead to greater risk. However, a causal dose-dependent effect of alcohol consumption on smoking lapse behavior has not been established, and the mechanisms that might account for such an effect have not been tested.

OBJECTIVES

In a within-subjects design, we examined the effects of low- (0.4 g/kg) and high-dose (0.8 g/kg) alcohol, relative to placebo, on smokers' ability to resist initiating smoking after acute smoking abstinence.

METHODS

Participants were 100 heavy alcohol drinkers, smoking 10-30 cigarettes per day. Across three separate days, participants consumed placebo, low-dose, or high-dose alcohol following 3 h of smoking abstinence and, 35 min later, were offered the opportunity to smoke while resisting smoking was monetarily reinforced proportional to the amount of time delayed.

RESULTS

Consistent with a dose-response effect, participants smoked 3.35 min (95 % confidence intervals (CI) [-7.09, 0.40], p = .08) earlier following low-dose alcohol and 6.36 min (95 % CI [-9.99, -2.73], p = .0006) earlier following high-dose alcohol compared to drinking a placebo beverage. Effects of dose on smoking behavior were partially mediated by increases in urge to smoke. There was no evidence that alcohol's effects on urge to smoke or ability to resist smoking were mediated through its stimulating or sedating effects.

CONCLUSIONS

Alcohol can reduce the ability to resist smoking in a dose-dependent fashion, in part, due to its effect on increasing the intensity of smoking urges.

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

BACKGROUND

Heavy drinking smokers (HDS) have more difficulty quitting smoking than lighter drinkers or abstainers. The opioid antagonist naltrexone may improve smoking quit rates and reduce alcohol use in drinker-smokers, but its relative efficacy in smokers with a range of drinking patterns is unknown. The current study tested the hypothesis that HDS would show differential benefit of naltrexone versus placebo relative to moderate-to-light or nondrinking smokers in terms of improving smoking outcomes and reducing alcohol consumption.

METHODS

Adult smokers (N = 315) enrolled in a 12-week, double-blinded, placebo-controlled trial of 50 mg naltrexone for smoking cessation were categorized into subgroups based upon past 6-month drinking patterns: HDS (n = 69; i.e., averaged ≥2 heavy drinking episodes per month), moderate-to-light drinking smokers (n = 204, i.e., consumed 1 drink up to a maximum of <2 heavy drinking episodes per month on average), or nondrinking smokers (n = 42, no alcohol consumed in the past 6 months). The groups were compared on the main study outcomes of biochemically verified prolonged abstinence quit rates (i.e., no smoking weeks 2 to 12), and smoking urge and alcohol use (drinks/wk) during treatment.

RESULTS

Naltrexone significantly increased 12-week smoking abstinence rates and decreased smoking urge and alcohol use among HDS, but not moderate-to-light or nondrinking smokers. Mediation analyses in HDS revealed that naltrexone's effect on smoking urge during the first 4 weeks of treatment mediated its effect on quit rates.

CONCLUSIONS

HDS appear to be particularly sensitive to naltrexone effects on smoking and drinking outcomes. This group may represent an important target for adjunctive treatment with naltrexone to optimize smoking cessation outcomes.

Efficacy of interventions to combat tobacco addiction: Cochrane update of 2013 reviews

AIMS

The Cochrane Collaboration is an international not-for profit organization which produces and disseminates systematic reviews. This paper is the second in a series of annual updates of Cochrane reviews on tobacco addiction interventions, covering new and updated reviews from 2013.

METHODS

In 2013, the Group published two new reviews and updated 11 others. This update summarizes and comments on these reviews as well as on a review of psychosocial interventions for smoking cessation in pregnant women, and presents pooled results from reviews of cessation interventions.

RESULTS

New reviews in 2013 found: low-quality evidence that behavioural interventions with mood management components could significantly increase long-term quit rates in people with current [risk ratio (RR) = 1.47, 95% confidence interval (CI) = 1.13-1.92) and past (RR = 1.41, 95% CI = 1.13-1.77] depression; evidence from network meta-analysis that varenicline and combined forms of nicotine replacement therapy (NRT) are associated with higher quit rates than bupropion or single-form NRT (varenicline versus single-form NRT odds ratio (OR) = 1.57, 95% credibility interval (CredI) = 1.29-1.91; versus bupropion OR = 1.59, 95% CredI = 1.29-1.96); and no evidence of a significant increase in serious adverse events in trial participants randomized to varenicline or bupropion when compared to placebo controls. New evidence emerging from updated reviews suggests that counselling interventions can increase quit rates in pregnant women and that school-based smoking programmes with social competence curricula can lead to a significant reduction in uptake of smoking at more than a year. Updated reviews also suggested that naltrexone, selective serotonin re-uptake inhibitors and St John's wort do not have a significant effect on long-term smoking cessation.

CONCLUSIONS

Cochrane systematic review evidence from 2013 suggests that adding mood management to behavioural support may improve cessation outcomes in smokers with current or past depression and strengthens evidence for previous conclusions, including the safety of varenicline and bupropion and the benefits of behavioural support for smoking cessation in pregnancy.

Spontaneous reductions in smoking during double-blind buprenorphine detoxification

OBJECTIVE

Evidence suggests a positive association between administration of psychoactive drugs and rates of cigarette smoking. Prevalence of smoking among opioid-dependent individuals, for example, is four times greater than the general population. We recently completed a randomized double-blind trial evaluating outpatient buprenorphine taper for prescription opioid (PO) abusers, which provided a unique opportunity to examine naturalistic changes in smoking among participants who detoxified without resumption of illicit opioid use.

METHOD

Participants received no smoking-cessation services and were not encouraged to alter their smoking in any way. A subset of 10 opioid-dependent smokers, who were randomized to receive the same 4-week buprenorphine taper and successfully completed detoxification, were included in the present study. They provided staff-observed urine specimens thrice-weekly throughout the 12-week trial. Specimens were analyzed on-site via enzyme-multiplied immunoassay for urinary cotinine, a metabolite of nicotine that provides a sensitive biochemical measure of smoking status.

RESULTS

Mean cotinine levels were significantly different across study phases, with significantly lower cotinine levels during taper (1317.5 ng/ml) and post-taper (1015.8 ng/ml) vs. intake (1648.5 ng/ml) phases (p''s<.05). Overall, mean cotinine levels decreased by 38% between intake and end-of-study, reflecting a reduction of approximately eight cigarettes per day.

CONCLUSIONS

These data provide additional evidence that opioids influence smoking and extend prior findings to include primary PO abusers, rigorous double-blind opioid dosing conditions and urinary cotinine. These results also suggest that, while likely insufficient for complete cessation, patients who successfully taper from opioids may also experience concurrent reductions in smoking and thus may be ideal candidates for smoking cessation services.

Systematic review and meta-analysis of opioid antagonists for smoking cessation

OBJECTIVES

This meta-analysis sought to evaluate the efficacy of opioid antagonists in promoting long-term smoking cessation. Post-treatment abstinence was examined as a secondary outcome and effects on withdrawal symptoms, craving and reduced consumption were also explored.

DESIGN

The search strategy for this meta-analysis included clinical trials (published and unpublished data) in the Cochrane Tobacco Addiction Group Specialized Register and MEDLINE.

PARTICIPANTS

Adult smokers.

INTERVENTIONS

We included randomised trials comparing opioid antagonists to placebo or an alternative therapy for smoking cessation and reported data on abstinence for a minimum of 6 months.

PRIMARY AND SECONDARY OUTCOME MEASURES

Outcomes included smoking abstinence at long-term follow-up (primary); abstinence at end of treatment (secondary); and effects on withdrawal, craving and smoking consumption (exploratory).

RESULTS

8 trials with a total of 1213 participants were included. Half the trials examined the benefit of adding naltrexone versus placebo to nicotine replacement therapy (NRT). There was no significant difference between naltrexone and placebo alone (relative risk (RR) 1.00; 95% CI 0.66 to 1.51) or as an adjunct to NRT (RR 0.95; 95% CI 0.70 to 1.30), with an overall pooled estimate of RR 0.97; 95% CI 0.76 to 1.24. Findings for naltrexone effects on withdrawal, craving and reduced smoking were equivocal.

CONCLUSIONS

The findings indicate no beneficial effect of naltrexone alone or as an adjunct to NRT on short-term or long-term smoking abstinence. While further trials may narrow the confidence limits, they are unlikely to appreciably alter the conclusion.

Effects of the opioid receptor antagonist naltrexone on smoking and related behaviors in smokers preparing to quit: a randomized controlled trial

AIMS

To determine if naltrexone affects smoking behaviors in smokers preparing to quit, and whether or not such pre-quit responses predict post-quit date outcomes.

DESIGN

Double-blind, placebo-controlled, randomized study. The current study focused on smoking-related outcomes in the pre-quit phase, which was 1 week prior to the quit date, and these findings were linked with reductions in the same outcomes demonstrated in the post-quit phase published previously for this randomized controlled trial (RCT) in mediation analyses.

SETTING

Community sample of adult smokers desiring to quit in Chicago, Illinois, USA.

PARTICIPANTS

Participants were 315 smokers randomized to naltrexone (n = 161; mean age = 42.58 years; 60% Caucasian) or placebo (n = 154; mean age = 41.32 years; 55% Caucasian).

MEASUREMENTS

The difference from baseline in the number of cigarettes smoked during the pre-quit phase interval was the primary outcome. Secondary pre-quit outcomes were assessed using Likert scales of subjective responses and consumption of cigarettes, alcohol and food. Number of cigarettes smoked, alcoholic drinks consumed and the Brief Questionnaire of Smoking Urges were assessed in the post-quit phase.

FINDINGS

Relative to placebo, naltrexone decreased the number of cigarettes smoked (-4.21 versus -2.93, P < 0.05), smoking urge (P = 0.02) and number of alcoholic drinks consumed (P = 0.04). Exploratory mediation analyses linking outcomes of the pre-quit and post-quit phases found that naltrexone's effects on reducing smoking urge, cigarettes smoked and alcoholic drinks consumed in the pre-quit phase demonstrated full mediation of their respective effects during the post-quit phase.

CONCLUSIONS

Naltrexone taken in the week before a quit attempt reduces cigarette consumption, urges to smoke and alcohol consumption relative to placebo. The size of the effect mediates statistically the size of similar effects after the quit date.