Varenicline and neuronal nicotinic acetylcholine receptors: a new approach to the treatment of co-occurring alcohol and nicotine addiction?

Emerging drugs in phase II and III clinical development for the treatment of alcohol use disorder

INTRODUCTION

Alcohol Use Disorder (AUD) poses an ongoing significant global health burden. AUD is highly prevalent and affects not only the individuals with AUD, but also their communities and society at large. Even though pharmacotherapy is an integral part of AUD treatment, the few available substances show limited efficacy and limited clinical impact. Thus, there is a need for new innovative pharmacotherapeutic approaches.

AREAS COVERED

This paper provides a comprehensive review of drugs approved for the treatment of AUD as well as those currently in phase II and III development. Data from recent clinical trials has been reviewed and supplemented by additional literature based on a systematic search of the PubMed database and clinical trials registries. Compounds discussed include disulfiram, naltrexone, nalmefene, acamprosat, baclofen, sodium oxybate, doxazosin, varenicline, zonisamide, gabapentin, apremilast, ibudilast, ivermectin, tolcapone, mifepristone, suvorexant, ketamine, psilocybin, semaglutide, oxytocin and cannabidiol.

EXPERT OPINION

Even though the majority of the discussed compounds lack sufficient evidence to support their efficacy, multiple promising new treatment options are currently under investigation. Future research has to consider specific phenotypes and subgroups of AUD as well as a possible enhancement of the effects of psychotherapy through combination with pharmacotherapy. Practitioners should be encouraged to use available compounds to support existing therapeutic regimens.

A novel tramadol-polycaprolactone implant could palliate heroin conditioned place preference and withdrawal in rats: behavioral and neurochemical study

Drug dependence is a chronic brain disease characterized by craving and recurrent episodes of relapse. Tramadol HCl is a promising agent for withdrawal symptoms management, considering its relatively low abuse potential and safety. Oral administration, however, is not preferred in abstinence maintenance programs. Introducing an implantable, long-lasting formula is suggested to help outpatient abstinence programs achieve higher rates of treatment continuation. Tramadol implants (T350 and T650) were prepared on polycaprolactone polymer ribbons by the wet method. Male Wistar rats were adapted to heroin-conditioned place preference (CPP) at escalating doses (3-30 mg/kg, intraperitoneally, for 14 days). Implants were surgically implanted in the back skin of rats. After 14 days, the CPP score was recorded. Naloxone (1 mg/kg, intraperitoneally) was used to induce withdrawal on day 15, and symptoms were scored. Elevated plus maze and open field tests were performed for anxiety-related symptoms. Striata were analyzed for neurochemical changes reflected in dopamine, 3,4-dihydroxyphenyl acetic acid, gamma-aminobutyric acid, and serotonin levels. Brain oxidative changes including glutathione and lipid peroxides were assessed. The tramadol implants (T350 and T650) reduced heroin CPP and limited naloxone-induced withdrawal symptoms. The striata showed increased levels of 3,4-dihydroxyphenyl acetic acid, and serotonin and decreased levels of gamma-aminobutyric acid and dopamine after heroin withdrawal induction, which were reversed after implanting T350 and T650. Implants restore the brain oxidative state. Nonsignificant low naloxone-induced withdrawal score after the implant was used in naive subjects indicating low abuse potential of the implants. The presented tramadol implants were effective at diminishing heroin CPP and withdrawal in rats, suggesting further investigations for application in the management of opioid withdrawal.

Heterogeneous network propagation with forward similarity integration to enhance drug-target association prediction

Identification of drug-target interaction (DTI) is a crucial step to reduce time and cost in the drug discovery and development process. Since various biological data are publicly available, DTIs have been identified computationally. To predict DTIs, most existing methods focus on a single similarity measure of drugs and target proteins, whereas some recent methods integrate a particular set of drug and target similarity measures by a single integration function. Therefore, many DTIs are still missing. In this study, we propose heterogeneous network propagation with the forward similarity integration (FSI) algorithm, which systematically selects the optimal integration of multiple similarity measures of drugs and target proteins. Seven drug-drug and nine target-target similarity measures are applied with four distinct integration methods to finally create an optimal heterogeneous network model. Consequently, the optimal model uses the target similarity based on protein sequences and the fused drug similarity, which combines the similarity measures based on chemical structures, the Jaccard scores of drug-disease associations, and the cosine scores of drug-drug interactions. With an accuracy of 99.8%, this model significantly outperforms others that utilize different similarity measures of drugs and target proteins. In addition, the validation of the DTI predictions of this model demonstrates the ability of our method to discover missing potential DTIs.

Off-label and investigational drugs in the treatment of alcohol use disorder: A critical review

Compounds known to be successful in the treatment of alcohol use disorder include the aversive agent, Disulfiram, the glutamatergic NMDA receptor antagonist, Acamprosate, and the opioid receptor antagonists, Naltrexone and Nalmefene. Although all four are effective in maintaining abstinence or reduction of alcohol consumption, only a small percentage of patients receive pharmacological treatment. In addition, many other medications have been investigated for their therapeutic potential in the treatment of alcohol use disorder. In this review we summarize and compare Baclofen, Gabapentin, Topiramate, Ondansetron, Varenicline, Aripiprazole, Quetiapine, Clozapine, Antidepressants, Lithium, Neuropeptide Y, Neuropeptide S, Corticotropin-releasing factor antagonists, Oxytocin, PF-05190457, Memantine, Ifenprodil, Samidorphan, Ondelopran, ABT-436, SSR149415, Mifepristone, Ibudilast, Citicoline, Rimonabant, Surinabant, AM4113 and Gamma-hydroxybutyrate While some have shown promising results in the treatment of alcohol use disorder, others have disappointed and should be excluded from further investigation. Here we discuss the most promising results and highlight medications that deserve further preclinical or clinical study. Effective, patient-tailored treatment will require greater understanding provided by many more preclinical and clinical studies.

Efficacy and acceptability of varenicline for alcoholism: A systematic review and meta-analysis of randomized-controlled trials

BACKGROUND

Current pharmacological treatment for alcoholism remains unsatisfactory. While there have been several clinical trials investigating the efficacy and safety of the therapeutic use of varenicline in alcoholism, no definitive review of this topic has been carried out. This systematic review aimed to determine the efficacy and acceptability of the use of varenicline in treating alcoholism.

METHODS

This systematic review included double-blinded, randomized, placebo-controlled trials reporting heavy drinking days, amount of alcohol consumption, overall dropouts, or dropouts due to adverse events. We searched PubMed, Scopus, Web of Science, ClinicalTrials.gov, and the Cochrane Library in January 2019. We independently selected the trials and assessed the quality of included studies. We calculated standardized mean differences on heavy drinking days and the amount of alcohol consumption. We calculated the relative risks for dropout rate. All data were pooled using random-effects models.

RESULT

This systematic review included nine double-blind, randomized, placebo-controlled trials (N = 585). The study duration ranged from 4 to 13 weeks. Varenicline therapy was not superior to placebo in decreasing heavy drinking days but significantly superior to placebo in decreasing alcohol consumption. There were no statistically significant differences between groups on dropout rates due to any reason or due to adverse events.

CONCLUSION

Varenicline therapy is effective in decreasing alcohol consumption over a period of time. It may be an option for decreasing heavy drinking days in patients with alcoholism. It is a well-accepted medication for alcoholism. More studies are needed to determine if varenicline is effective in decreasing heavy drinking.

Prolonged exposure of rats to varenicline increases anxiety and alters serotonergic system, but has no effect on memory

Varenicline is a drug used for smoking addiction cessation treatment and acts as a partial agonist of nicotinic cholinergic receptors. Recent clinical trial data support use of varenicline for treatment of conditions/addictions that are not related to smoking cessation. Considering the importance of this issue and the need for new studies on its effects, especially on behavior, more studies using animal models are necessary. Thus, the aim of this study was to evaluate the effects of prolonged exposure to varenicline in anxiety-like behavior and memory, as well as in cerebral neurochemistry of rats. Male rats received three different doses of varenicline: 0.03 (therapeutic dose for humans), 0.1 and 0.3 mg/kg orally (gavage) for 30 days. Animal behavior was analyzed through open field, elevated plus maze, light/dark box, social interaction, Barnes maze and novel object recognition tests. Neurotransmitter levels and their metabolites in different brain structures (hippocampus, striatum and frontal cortex) were measured. Results showed that prolonged exposure of rats to varenicline: 1) did not interfere in motor activity, but caused an anxiogenic effect on elevated plus maze, light/dark box and social interaction testes; 2) did not alter memory; and 3) promoted alterations on serotoninergic system in the striatum and frontal cortex. In conclusion, compilation of the data indicates that prolonged exposure of rats to varenicline promoted anxiogenic effects and alteration in serotonergic system, which corroborated behavioral findings.

Predictors of tobacco and alcohol co-use from ages 15 to 32: The Amsterdam Growth and Health Longitudinal Study

Tobacco and alcohol are often used in tandem over time, but specific predictors of course and patterns of course over time need explication. We examined differences in alcohol and tobacco course among an adolescent population as they transitioned into young adulthood across a 17-year period. Data came from participants (n = 303 for ages 15-21, n = 196 for ages 21 to 32; 52% female and 54% female, respectively) enrolled in the Amsterdam Growth and Health Longitudinal Study, an epidemiologic investigation examining disease across the life span. We utilized parallel latent growth modeling to assess the impact of sex, personality traits, cholesterol, blood pressure, and body mass index (BMI), on initial status and linear change over time in course of tobacco and alcohol. Females reported less alcohol use at adolescent baseline (β = -21.79), less increase during adolescence (β = -7.92, p < .05), slower decrease during young adulthood (β = 4.67, p < .05), and more rapid decline in tobacco use during young adulthood (β = -70.85, p < .05), relative to males. Alcohol and tobacco use baseline status' and change over time were all significantly associated with one another during both adolescence and young adulthood (p < .05; aside from alcohol baseline and slope during young adulthood). Effects of BMI, cholesterol, blood pressure, and personality traits were also observed on tobacco and alcohol course. In light of the strong, but sex dependent relationship between alcohol and tobacco course, particularly from ages 15 to 21, prevention efforts to curb heavy alcohol and tobacco use should consider targeting course taking into account biological sex and other notable covariates. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Pilot investigation: randomized-controlled analog trial for alcohol and tobacco smoking co-addiction using contingency management

Contingency management (CM) is associated with decreases in off-target drug and alcohol use during primary target treatment. The primary hypothesis for this trial was that targeting alcohol use or tobacco smoking would yield increased abstinence in the opposite, nontargeted drug. We used a 2 [CM vs. noncontingent control (NC) for alcohol]×2 (CM vs. NC for smoking tobacco) factorial design, with alcohol intake (through urinary ethyl glucuronide) and tobacco smoking (through urinary cotinine) as the primary outcomes. Thirty-four heavy-drinking smokers were randomized into one of four groups, wherein they received CM, or equivalent NC reinforcement, for alcohol abstinence, smoking abstinence, both drugs, or neither drug. The CM for alcohol and tobacco group had only two participants and therefore was not included in analysis. Compared with the NC for alcohol and tobacco smoking group, both the CM for the tobacco smoking group [odds ratio (OR)=12.03; 95% confidence interval (CI): 1.50-96.31] and the CM for the alcohol group (OR=37.55; 95% CI: 4.86-290.17) submitted significantly more tobacco-abstinent urinalyses. Similarly, compared with the NC for the alcohol and tobacco group, both the CM for smoking (OR=2.57; 95% CI: 1.00-6.60) and the CM for alcohol groups (OR=3.96; 95% CI: 1.47-10.62) submitted significantly more alcohol-abstinent urinalyses. These data indicate cross-over effects of CM on indirect treatment targets. Although this is a pilot investigation, it could help to inform the design of novel treatments for alcohol and tobacco co-addiction.

Varenicline for tobacco-dependence treatment in alcohol-dependent smokers: A randomized controlled trial

BACKGROUND

Tobacco use is prevalent among persons with alcohol abuse and dependence. Varenicline has been shown to be the most effective pharmacotherapy for smoking cessation and may decrease alcohol consumption. The purpose of this study was to evaluate the efficacy of 12 weeks of varenicline for increasing smoking abstinence rates in smokers with alcohol abuse or dependence.

METHODS

Participants were eligible for enrollment if they were 18 years or older, smoked 10 or more cigarettes per day for at least 6 months, had current alcohol abuse or dependence, and were interested in quitting smoking. Participants were randomly assigned to receive 12 weeks of varenicline 1 mg twice daily or matching placebo. The primary end point was 7-day point prevalence smoking abstinence at week 12.

RESULTS

The 7-day point prevalence smoking abstinence rate at 12 weeks was significantly higher with varenicline (n = 16) than placebo (n = 17) (43.8% vs 5.9%; P = .01). At 24 weeks, the 7-day point prevalence smoking abstinence rate was still significantly higher with varenicline than placebo (31.3% vs 0%; P = .02). At 12 weeks, mean (SD) drinks per drinking day was significantly lower with varenicline than placebo (5.7 [3.9] vs 9.0 [5.3] drinks; treatment effect estimate, -2.8 [90% CI, -6.6 to -1.0]). Adverse events were minor and comparable to varenicline clinical trials.

CONCLUSIONS

Varenicline is safe and efficacious for increasing smoking abstinence rates in smokers with alcohol abuse or dependence. Varenicline may decrease alcohol consumption in this population of smokers.

Blockade of nicotine sensitization by methanol extracts of Glycyrrhizae radix mediated via antagonism of accumbal oxidative stress

BACKGROUND

We previously reported that a methanol extract of Glycyrrhizae radix (MEGR) blocked methamphetamine-induced locomotor sensitization and conditioned place preference in rats. In the present study, the effects of MEGR on repeated nicotine-induced locomotor sensitization and enhanced extracellular dopamine (DA) release in the nucleus accumbens (Nacc) were evaluated.

METHODS

Male Sprague-Dawley rats received repeated administrations of nicotine (0.4 mg/kg, subcutaneous) or saline twice a day for 7 d and were challenged with nicotine 4 d after the last daily dosing. During the 4-d withdrawal period, the rats were treated once a day with MEGR (60 or 180 mg/kg/d). Extracellular DA levels were measured by in vivo microdialysis, the malondialdehyde levels and the activities of superoxide dismutase and catalase in the Nacc were biochemically evaluated, and the expression of antioxidant proteins was confirmed by Western blot assays. All data were assessed with analysis of variance tests followed by post-hoc comparison tests and p values <0.05 were considered statistically significant.

RESULTS

The expression of repeated nicotine-induced locomotor sensitization was dose-dependently attenuated by MEGR, and 180 mg/kg/d MEGR significantly inhibited augmented accumbal DA release induced by a direct local challenge of nicotine. Moreover, 180 mg/kg/d MEGR reversed increases in malondialdehyde production, decreases in superoxide dismutase and catalase activities, and the reduced expression of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1 in the nicotine-sensitized Nacc.

CONCLUSIONS

These results suggest that MEGR inhibited nicotine-induced locomotion and dopaminergic sensitization via antioxidant action.

Evaluation of Prolonged Exposure to Varenicline in Adult Rats: Haematological, Biochemical and Anatomopathological Studies

Varenicline is a synthetic chemical substance produced from the alkaloid cytisine, used for smoking treatment, which acts as a partial agonist for α4β2 and α3β4 nicotinic cholinergic receptors and as a total agonist for α7 receptor. While there are studies regarding varenicline's non-smoking-related effects, as in treatment for drug dependence, there are no studies in the literature evaluating the long-term toxicity of varenicline through a physiological approach. Thus, the aim of this study was to evaluate possible toxicity through haematological, biochemical and anatomopathological parameters of prolonged exposure (30 days) to varenicline in rats. Three doses of varenicline were used: 0.03 (therapeutic dose for human beings), 0.1 and 0.3 mg/kg orally (gavage). Body-weight, water and food intake were measured weekly during treatment. On the 30th treatment day, blood and various organs were collected for haematological, biochemical and anatomopathological evaluations. The results show a decrease in some biochemical parameters in animals from the 0.1 and 0.3 mg/kg group, although the values are within the normal range of the species. There were no changes in the other evaluations performed. Together, these data indicate that prolonged exposure of rats to different doses of varenicline was not able to alter haematological, biochemical and anatomopathological parameters.

Immediate and Sustained Decrease in Smoking Urges After Acute Insular Cortex Damage

INTRODUCTION

Smoking urges are fundamental aspects of nicotine dependence that contribute significantly to drug use and postquit relapse. Recent evidence has indicated that damage to the insular cortex disrupts smoking behaviors and claims to reduce urges associated with nicotine use, although tools that assess urge have yet to be used to validate these findings. We examined the effect of insular versus non-insular damage on urge using a well-accepted urge scale.

METHODS

This 3-month observational prospective cohort study consisted of 156 current smokers hospitalized for acute ischemic stroke (38 with insular infarctions, 118 with non-insular infarctions). During hospitalization, the Questionnaire of Smoking Urges (QSU)-brief was assessed retrospectively based on experiences before the stroke (baseline, T0), prospectively immediately following the stroke (T1) and once more via telephone at 3-month follow-up (T2), with higher scores indicating greater urge. Bivariate statistics and multivariable linear regression were used to evaluate differences in QSU-brief scores, relative to baseline, between exposure groups, controlling for age, baseline dependence, stroke severity, use of nicotine replacement, and damage to other mesocorticolimbic regions.

RESULTS

A greater reduction in QSU-brief score was seen in the insular group compared to the non-insular group from T0 to T1 (covariate-adjusted difference in means of -1.15, 95% CI: -1.85, -0.44) and similarly from T0 to T2 (covariate-adjusted difference in means of -0.93, 95% CI: -1.79, -0.07).

CONCLUSIONS

These findings confirm the potential role of the insula in regulating nicotine-induced urges and support the growing evidence of its novelty as a key target for smoking cessation interventions.

IMPLICATIONS

Human lesioning studies that evaluate the insula's involvement in maintaining nicotine addiction make inferences of the insula's role in decreasing urge, but do not use validated instruments that directly assess urges. This study corroborates prior findings using the continuous Questionnaire of Smoking Urges to quantify changes in urge from before lesion onset to immediate and 3-month follow-up time points.

Guidelines for biological treatment of substance use and related disorders, part 1: Alcoholism, first revision

These practice guidelines for the biological treatment of alcohol use disorders are an update of the first edition, published in 2008, which was developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBP). For this 2016 revision, we performed a systematic review (MEDLINE/PUBMED database, Cochrane Library) of all available publications pertaining to the biological treatment of alcoholism and extracted data from national guidelines. The Task Force evaluated the identified literature with respect to the strength of evidence for the efficacy of each medication and subsequently categorised it into six levels of evidence (A-F) and five levels of recommendation (1-5). Thus, the current guidelines provide a clinically and scientifically relevant, evidence-based update of our earlier recommendations. These guidelines are intended for use by clinicians and practitioners who evaluate and treat people with alcohol use disorders and are primarily concerned with the biological treatment of adults with such disorders.

PET imaging of α7 nicotinic acetylcholine receptors: a comparative study of [18F]ASEM and [18F]DBT-10 in nonhuman primates, and further evaluation of [18F]ASEM in humans

PURPOSE

The α₇ nicotinic acetylcholine receptor (nAChR) is implicated in many neuropsychiatric disorders, making it an important target for positron emission tomography (PET) imaging. The first aim of this work was to compare two α₇ nAChRs PET radioligands, [¹⁸F]ASEM (3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-6-([¹⁸F]fluorodibenzo[b,d]thiophene 5,5-dioxide) and [¹⁸F]DBT-10 (7-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-2-([¹⁸F]fluorodibenzo[b,d]thiophene 5,5-dioxide), in nonhuman primates. The second aim was to assess further the quantification and test-retest variability of [¹⁸F]ASEM in humans.

METHODS

PET scans with high specific activity [¹⁸F]ASEM or [¹⁸F]DBT-10 were acquired in three rhesus monkeys (one male, two female), and the kinetic properties of these radiotracers were compared. Additional [¹⁸F]ASEM PET scans with blocking doses of nicotine, varenicline, and cold ASEM were acquired separately in two animals. Next, six human subjects (five male, one female) were imaged with [¹⁸F]ASEM PET for 180 min, and arterial sampling was used to measure the parent input function. Different modeling approaches were compared to identify the optimal analysis method and scan duration for quantification of [¹⁸F]ASEM distribution volume (V _T). In addition, retest scans were acquired in four subjects (three male, one female), and the test-retest variability of V _T was assessed.

RESULTS

In the rhesus monkey brain [¹⁸F]ASEM and [¹⁸F]DBT-10 exhibited highly similar kinetic profiles. Dose-dependent blockade of [¹⁸F]ASEM binding was observed, while administration of either nicotine or varenicline did not change [¹⁸F]ASEM V _T. [¹⁸F]ASEM was selected for further validation because it has been used in humans. Accurate quantification of [¹⁸F]ASEM V _T in humans was achieved using multilinear analysis with at least 90 min of data acquisition, resulting in V _T values ranging from 19.6 ± 2.5 mL/cm³ in cerebellum to 25.9 ± 2.9 mL/cm³ in thalamus. Test-retest variability of V _T was 11.7 ± 9.8%.

CONCLUSIONS

These results confirm [¹⁸F]ASEM as a suitable radiotracer for the imaging and quantification of α₇ nAChRs in humans.

Treatment-refractory substance use disorder: Focus on alcohol, opioids, and cocaine

Substance use disorders are common, but only a small minority of patients receive adequate treatment. Although psychosocial therapies are effective, relapse is common. This review focusses on novel pharmacological and other treatments for patients with alcohol, opioid, or cocaine use disorders who do not respond to conventional treatments. Disulfiram, acamprosate, and the opioid antagonist naltrexone have been approved for the treatment of alcoholism. A novel, "as needed" approach is the use of the mu-opioid antagonist and partial kappa agonist nalmefene to reduce alcohol consumption. Other novel pharmacological approaches include the GABA-B receptor agonist baclofen, anticonvulsants such as topiramate and gabapentin, the partial nicotine receptor agonist varenicline, and other drugs. For opioid dependence, opioid agonist therapy with methadone or buprenorphine is the first-line treatment option. Other options include oral or depot naltrexone, morphine sulfate, depot or implant formulations, and heroin (diacetylmorphine) in treatment-refractory patients. To date, no pharmacological treatment has been approved for cocaine addiction; however, 3 potential pharmacological treatments are being studied, disulfiram, methylphenidate, and modafinil. Pharmacogenetic approaches may help to optimize treatment response in otherwise treatment-refractory patients and to identify which patients are more likely to respond to treatment, and neuromodulation techniques such as repeated transcranial magnetic stimulation and deep brain stimulation also may play a role in the treatment of substance use disorders. Although no magic bullet is in sight for treatment-refractory patients, some novel medications and brain stimulation techniques have the potential to enrich treatment options at least for some patients.

Interactions between nicotine and drugs of abuse: a review of preclinical findings

Polysubstance abuse is common among substance-use disorder patients, and nicotine is one of the most commonly co-used substances. Epidemiological and clinical laboratory studies suggest that nicotine, when combined with other drugs of abuse, increases intake of one or both substances. This review focuses on the preclinical literature regarding nicotine's interaction with alcohol, stimulants (i.e., cocaine, amphetamines), opioids (i.e., morphine, heroin), and Δ⁹-tetrahydrocannabinol (THC). The current understanding of how these various classes of abused drugs may interact with nicotine on behavioral, physiological, and pharmacological indices that may be important in maintaining co-use of one or both substances in human populations are highlighted. Suggestions as to future areas of research and gaps in knowledge are offered.

Moderators of Varenicline Treatment Effects in a Double-Blind, Placebo-Controlled Trial for Alcohol Dependence: An Exploratory Analysis

OBJECTIVES

To explore whether varenicline (Chantix) showed more efficacy in treating certain subgroups of patients. In a recent multisite trial, varenicline was shown to be effective in reducing drinking in alcohol-dependent patients, both smokers and nonsmokers. Given the heterogeneity among alcohol-dependent patients, secondary analyses were conducted to determine whether certain subgroups responded more favorably than others to treatment with varenicline.

METHODS

Data were drawn from a phase 2 randomized, double-blind, placebo-controlled multisite 13-week trial of varenicline in alcohol-dependent patients (Litten et al., 2013). Seventeen moderator variables were selected for exploratory testing on the basis of theoretical and scientific interest.

RESULTS

Of the 17 moderator variables assessed, 4 were statistically significant, including cigarettes per day reduction, treatment drinking goal, years drinking regularly, and age of the patient. Two other variables—the type of adverse events experienced by patients and the severity of alcohol-related consequences—seemed to moderate the varenicline treatment effect at borderline statistical significance. Individuals who reduced the number of cigarettes per day experienced a significant effect from varenicline in reducing drinking, whereas those who did not change or who increased their number of cigarettes observed no beneficial effect. Reviewing the moderators related to severity, varenicline seemed to have greater efficacy than placebo among less severely dependent patients.

CONCLUSIONS

Varenicline seems to be more efficacious in certain subgroups, particularly in those who reduced their smoking and in the "less severe" patient. Additional studies are warranted to confirm the results of these exploratory analyses.

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.

Smoking cessation behaviors three months following acute insular damage from stroke

BACKGROUND

Recent evidence suggests that the insular cortex may play an important role in cognitive and emotional processes that facilitate drug use but it is unclear whether changes to the insula would result in sustained abstinence. To better understand the role of the insula in maintaining abstinence, we examined quitting patterns in smokers with acute damage to their insula relative to other regions.

DESIGN

Prospective cohort study with 3month follow-up, beginning June 2013 and ending May 2014.

SETTING

Three acute care hospitals in Rochester, NY.

PARTICIPANTS

One-hundred-fifty-six current smokers hospitalized for acute ischemic stroke; 38 with insular infarctions and 118 with non-insular infarctions, assessed by 3 neuroradiologists.

MEASUREMENTS

Self-reported smoking status (seven-day point prevalence and continuous abstinence), complete abstinence from any nicotine product, and disruption of smoking addiction (defined by criteria on smoking status, difficulty of quitting, and urge) were assessed at three months post-stroke. Time to relapse (in days) after discharge was also assessed.

RESULTS

Insular damage was associated with increased odds of three-month continuous abstinence (OR=3.71, 95% CI: 1.59, 8.65) and complete cessation from any nicotine product (OR=2.72, 95% CI: 1.19, 6.22). Average time to relapse was longer in the insular-damaged group (17.50days, SD=19.82) relative to non-insular damage (10.42days, SD=18.49). Among quitters, insular damage was also associated with higher relative odds of experiencing a disruption of addiction compared to non-insular damage (adjusted OR=5.60, 95% CI: 1.52, 20.56).

CONCLUSIONS

These findings support the potential role of the insular cortex in maintaining smoking and nicotine abstinence. Further research is needed to establish whether the insula may be a novel target for smoking cessation interventions.

Working memory-related neural activity predicts future smoking relapse

Brief abstinence from smoking impairs cognition, particularly executive function, and this has a role in relapse to smoking. This study examined whether working memory-related brain activity predicts subsequent smoking relapse above and beyond standard clinical and behavioral measures. Eighty treatment-seeking smokers completed two functional magnetic resonance imaging sessions (smoking satiety vs 24 h abstinence challenge) during performance of a visual N-back task. Brief counseling and a short-term quit attempt followed. Relapse during the first 7 days was biochemically confirmed by the presence of the nicotine metabolite cotinine. Mean percent blood oxygen level-dependent (BOLD) signal change was extracted from a priori regions of interest: bilateral dorsolateral prefrontal cortex (DLPFC), medial frontal/cingulate gyrus, posterior cingulate cortex (PCC), and ventromedial prefrontal cortex. Signal from these brain regions and additional clinical measures were used to model outcome status, which was then validated with resampling techniques. Relapse to smoking was predicted by increased withdrawal symptoms, decreased left DLPFC and increased PCC BOLD percent signal change (abstinence vs smoking satiety). Receiver operating characteristic analysis demonstrated 81% area under the curve using these predictors, a significant improvement over the model with clinical variables only. The combination of abstinence-induced decreases in left DLPFC activation and reduced suppression of PCC may be a prognostic marker for poor outcome, specifically early smoking relapse.

Pharmacotherapy for alcohol use disorder: current and emerging therapies

Alcohol use disorder is a heterogeneous illness with a complex biology that is controlled by many genes and gene-by-environment interactions. Several efficacious, evidence-based treatments currently exist for treating and managing alcohol use disorder, including a number of pharmacotherapies that target specific aspects of biology that initiate and maintain dangerous alcohol misuse. This article reviews the neurobiological and neurobehavioral foundation of alcohol use disorder, the mechanisms of action and evidence for the efficacy of currently approved medications for treatment, and the literature on other emerging pharmacotherapies.

Varenicline in the treatment of alcohol use disorders

OBJECTIVE

To summarize the efficacy and safety data for the use of varenicline in the treatment of alcohol use disorders.

DATA SOURCES

A literature search was conducted in PubMed, International Pharmaceutical Abstracts, and Cochrane Library (through May 2014). Key search terms included varenicline, alcohol, alcohol dependence, alcoholism, ethanol, and nicotinic acetylcholine receptor. Additional references were identified from literature citations.

STUDY SELECTION AND DATA EXTRACTION

Results were limited to clinical trials and case reports that discussed either the use of varenicline in alcohol drinking patients or adverse effects experienced with its use. Only English language studies in humans were reviewed.

DATA SYNTHESIS

In all, 7 randomized, placebo-controlled clinical trials and 1 open-label study were identified that evaluated the impact of varenicline on various drinking-related end points. The studies were conducted in patients dependent on alcohol (n=4), non-alcohol-dependent patients (n=3), and patients with a history of alcohol dependence but who had been abstinent for at least 6 months (n=1). The majority of the studies classified their participants as heavy drinkers; however, this definition varied across studies. Most studies included smokers, but 2 trials included both smokers and nonsmokers.

CONCLUSIONS

Evidence supports the use of varenicline for the reduction of alcohol craving as well as for the reduction of overall alcohol consumption in patients with alcohol use disorders. However, it is not likely to improve abstinence rates. Although most of the data were derived from patients with concurrent nicotine dependence, the effects of varenicline appear to occur independent of baseline smoking status.

Tobacco use and cessation for cancer survivors: an overview for clinicians

Approximately 30% of all cancer deaths in the United States are caused by tobacco use and smoking. Cancers of eighteen sites have been causally linked to smoking, the most common of which are the lung, head and neck, bladder, and esophagus. While quit rates and quit attempt rates are relatively high shortly after a cancer diagnosis, the recidivism rates are also high. Therefore, screening, treating, and preventing relapse to tobacco use is imperative among patients with and survivors of cancer. To date, research has consistently shown that a combination of pharmacologic and behavioral interventions is needed to achieve the highest smoking cessation rates, with a recent emphasis on individualized treatment as a most promising approach. Challenges in health care systems, including the lack of appropriate resources and provider training, have slowed the progress in addition to important clinical considerations relevant to the treatment of tobacco dependence (eg, a high degree of comorbidity with psychiatric disorders and other substance use disorders). However, continued tobacco use has been shown to limit the effectiveness of major cancer treatments and to increase the risk of complications and of developing secondary cancers. The authors recommend that oncology providers screen all patients for tobacco use and refer users to specialized treatment when available. Alternatively, oncology clinicians can provide basic advice on tobacco use cessation and pharmacotherapy and/or referral to outside resources (eg, quitlines). Herein, the authors summarize the current knowledge on tobacco use and its treatment, with a focus on the related available evidence for patients with and survivors of cancer.