Nicotine and opioid co-dependence: Findings from bench research to clinical trials

Hepatitis C and Cigarette Smoking Behavior: Themes From Focus Groups

INTRODUCTION

People with chronic hepatitis C virus (HCV; PWHC) use cigarettes at a much higher prevalence than other individuals, and smoking can exacerbate the harms specifically related to HCV (eg, hepatocellular carcinoma). Little is known about factors related to cigarette use among PWHC.

AIMS AND METHODS

This study examined focus group data to explore beliefs and behaviors related to cigarette use among PWHC. Qualitative data from two focus groups of PWHC reporting current cigarette smoking (n = 15, 60% male) were collected using a semi-structured interview guide. Participants were asked about reasons for smoking, barriers to quitting smoking, and the relationship of HCV to smoking. Focus groups were transcribed verbatim and coded in NVivo 12. Four coders examined themes that arose in the focus groups. Common themes are described and supported with quotes.

RESULTS

Reasons for smoking included addiction to cigarettes, stress, substituting cigarettes for other drugs, and social norms, while reasons for quitting included health and being free from the use of all drugs. Barriers to quitting included concerns about coping with stress, weight gain, and having a lack of support for and education about quitting. Many participants believed there was a link between smoking and HCV and discussed smoking in relation to the stress of an HCV diagnosis.

CONCLUSIONS

Participants identified both HCV-related and non-HCV-related aspects of cigarette smoking and cessation-related behaviors that could be targeted in cessation treatment. More research is needed to identify the best treatment approaches that reduce the significant medical consequences of cigarette use among PWHC.

IMPLICATIONS

People with chronic hepatitis C virus (HCV; PWHC) smoke cigarettes at a high prevalence, yet little is known about their smoking behaviors. Moreover, there are no cessation treatments targeting PWHC. This is the first study to collect focus group data from PWHC who smoke in order to identify reasons for cigarette use (HCV-related and non-HCV-related), and motivators and barriers to quitting cigarettes. PWHC reports using cigarettes to cope with the stress of an HCV diagnosis and to celebrate HCV cure. These findings suggest there are specific times during the HCV care continuum where providers can aid with cessation efforts.

Adolescent nicotine exposure promotes adulthood opioid consumption that persists despite adverse consequences and increases the density of insular perineuronal nets

Adolescence marks a sensitive period for neurodevelopment wherein exposure to drugs of abuse may disrupt maturation and induce persistent changes in neurophysiology which may exacerbate the risk for developing substance use disorders in adulthood. Adolescent nicotine exposure (ANE) enhances motivation to obtain drugs of abuse, particularly opioids, and increases vulnerability for the development of opioid use disorder (OUD). Here, we characterized ANE effects on learning about the adverse consequences of opioid consumption in adulthood in the absence of further nicotine administration. First, we show that ANE engenders punishment resistant fentanyl self-administration in a heterogenous seeking-taking chain schedule of reinforcement at least at the tested dose of fentanyl (0.75 μg/kg). We found that ANE rats consumed significantly more fentanyl and contingent foot shock punishment was less efficacious in limiting fentanyl seeking in ANE rats, relative to nicotine-naïve controls. Next, we demonstrated that ANE limits learning about the deleterious consequences of acute opioid intoxication in adulthood. In a combined conditioned taste avoidance and place preference paradigm we found that ANE resulted in significant reductions in the strength of morphine-induced CTA, and a simultaneous enhancement of CPP at a higher dose that was less capable of driving reinforcement in naïve controls. Finally, we examined the expression of perineuronal nets (PNNs) within insular cortex (IC) and found ANE rats to have increased density of PNNs across the anterior IC and significantly more parvalbumin-labeled IC cells relative to naïve controls. Together, these data lay the framework for a mechanistic explanation of the extreme comorbidity between nicotine use and development of OUDs.

Disrupted brain state dynamics in opioid and alcohol use disorder: attenuation by nicotine use

Substance use disorder (SUD) is a chronic relapsing disorder with long-lasting changes in brain intrinsic networks. While most research to date has focused on static functional connectivity, less is known about the effect of chronic drug use on dynamics of brain networks. Here we investigated brain state dynamics in individuals with opioid use (OUD) and alcohol use disorder (AUD) and assessed how concomitant nicotine use, which is frequent among individuals with OUD and AUD, affects brain dynamics. Resting-state functional magnetic resonance imaging data of 27 OUD, 107 AUD, and 137 healthy participants were included in the analyses. To identify recurrent brain states and their dynamics, we applied a data-driven clustering approach that determines brain states at a single time frame. We found that OUD and AUD non-smokers displayed similar changes in brain state dynamics including decreased fractional occupancy or dwell time in default mode network (DMN)-dominated brain states and increased appearance rate in visual network (VIS)-dominated brain states, which were also reflected in transition probabilities of related brain states. Interestingly, co-use of nicotine affected brain states in an opposite manner by lowering VIS-dominated and enhancing DMN-dominated brain states in both OUD and AUD participants. Our finding revealed a similar pattern of brain state dynamics in OUD and AUD participants that differed from controls, with an opposite effect for nicotine use suggesting distinct effects of various drugs on brain state dynamics. Different strategies for treating SUD may need to be implemented based on patterns of co-morbid drug use.

A qualitative study on people with opioid use disorders' perspectives on smoking and smoking cessation interventions

Introduction

Smoking-related diseases are major contributors to disability and shorter life expectancy among opioid-dependent patients. Smoking prevalence is considerably higher for opioid-dependent persons than among the general population, and only a minority quit smoking in treatment settings. Studies show that pharmacological smoking cessation interventions have modest success rates. This study aimed to investigate patients' receiving opioid agonist therapy perspectives on factors affecting behavior and decisions related to smoking cessation, and their experiences with smoking cessation.

Methods

This is a qualitative study using semi-structured individual interviews. The participants were asked, among others, to elaborate on the participants' thoughts about smoking, previous attempts to quit tobacco use, and what could prompt a smoking cessation attempt. We analyzed the transcripts with systematic text condensation. The Standards for Reporting Qualitative Research and the Consolidated Criteria for Reporting Qualitative Research guidelines were followed. Opioid-dependent patients receiving opioid agonist therapy in outpatient clinics were invited to participate using a purposive sampling method. In total, fourteen individuals participated in this study.

Results

We identified six themes which were: (1) reflections on how smoking affected decisions, (2) smoking and its impact on physical and mental health, (3) the economy as a motivator to stop smoking, (4) emotions, desires, and habits related to smoking, (5) knowledge of smoking, smoking cessation, and quit attempts, and (6) social factors influencing the participants' choices and activities. The participants were well informed about the consequences of smoking and had some knowledge and experience in quitting. The participants' pulmonary health was an important motivational factor for change. Withdrawal symptoms, anxiety, and fear of using other substances discouraged several from attempting to quit smoking. In contrast, social support from partners and access to meaningful activities were considered important factors for success. Few reported being offered help from health professionals to make a smoking cessation attempt.

Discussion

Experiencing social support, being encouraged to quit smoking, and patients' concerns for their physical health were important reasons for wanting to quit smoking. Smoking cessation interventions based on patient preferences and on the behavior change wheel may enable a higher success rate among patients receiving opioid agonist therapy.

Mental health and substance use disorder comorbidities among Medicaid beneficiaries: Associations with opioid use disorder and prescription opioid misuse

Background

Medicaid presently insures about one-fourth of the US population and disproportionately insures about 38 % of non-elderly adults with an opioid use disorder (OUD). Owing to Medicaid's prominent role insuring persons with an OUD and that Medicaid coverage includes pharmaceutical benefits, there has been considerable interest in studying potential prescription opioid misuse among Medicaid beneficiaries and identifying subpopulations at higher risk for misuse and possible progression to an OUD.

Methods

The study goals were to explore the associations among prescription opioid misuse, OUD, and co-occurring mental health and other substance use disorders (SUD). We analyzed Illinois Medicaid 2018 claims data for 1102479 adult beneficiaries 18 to 64 years of age. Using algorithms based on previous studies, we first determined either the presence or absence of nine SUDS (including OUD), nine mental health disorders and likely prescription opioid misuse. Then, we subdivided the beneficiary sample into five groups: those who were prescribed opioids and evidenced either no, possible, or probable misuse; those evidencing an OUD; and those evidencing no opioid use or misuse.

Results

Bivariate analyses, upset plots, and multinomial logistic regressions were used to compare the five subgroups on the prevalence of co-occurring SUDS and mental health disorders. Those with an OUD or with probable prescription opioid misuse had the highest prevalence of most co-occurring conditions with beneficiaries with an OUD the most likely to evidence co-occurring SUDS, particularly tobacco use disorder, whereas those with probable misuse had elevated prevalence rates of co-occurring mental health disorders comparable to those with an OUD.

Conclusion

The medical complexity of persons with an OUD or misusing prescription opioids are considered in light of recent attempts to expand buprenorphine provision as a medication for OUD among Medicaid beneficiaries. Additionally, we consider the possibility of gender, co-occurring mental health disorders, and tobacco use disorder as important risk factors for progressing to prescription opioid misuse and an OUD.

Nicotine limits avoidance conditioning with opioids without interfering with the ability to discriminate an opioid-interoceptive state

Approximately 90 % of individuals undergoing treatment for opioid use disorder (OUD) report comorbid use of nicotine. As such, further investigation into underlying mechanisms contributing to the extreme comorbidity between nicotine and opioid use are warranted. Nicotine administration significantly escalates self-administration of opioids and this increase in motivational efficacy persists despite contingent punishment of opioid consumption. Additionally, both systemic and intra-insular administration of nicotine produces a rightward shift in the dose-response function in both morphine-induced conditioned place preference and taste avoidance paradigms, particularly at higher doses (5-20 mg/kg). Two possible interpretations arise from these outcomes. One is that nicotine may specifically affect learning about the malaise-inducing effects of morphine thus facilitating acceptance of higher doses of morphine. Another interpretation is that it more generally reduces sensitivity to the interoceptive effects of morphine such that higher doses are needed to produce comparable effects in nicotine-treated, relative to control, rats. To further address these possibilities, we asked whether nicotine administration interfered with the ability to discriminate the morphine interoceptive state, irrespective of its hedonic evaluation, at a dose that is impacted by nicotine in avoidance conditioning paradigms. First, we demonstrated that systemic nicotine pretreatment significantly attenuates taste avoidance induced by a low dose of morphine (3 mg/kg). Next, we used an occasion setting paradigm with this same dose of morphine to test whether systemic nicotine pretreatment interferes with the ability to discriminate between saline- and morphine-induced interoceptive states. Within this task, nicotine had no effect on the ability to effectively discriminate between the interoceptive effects of morphine and saline. Collectively, these data suggest that nicotine may be specifically altering the overall hedonic assessment of morphine perhaps by interfering with learning about its deleterious consequences.

Understanding the habenula: A major node in circuits regulating emotion and motivation

Over the last decade, the understanding of the habenula has rapidly advanced from being an understudied brain area with the Latin name 'habena" meaning "little rein", to being considered a "major rein" in the control of key monoaminergic brain centers. This ancient brain structure is a strategic node in the information flow from fronto-limbic brain areas to brainstem nuclei. As such, it plays a crucial role in regulating emotional, motivational, and cognitive behaviors and has been implicated in several neuropsychiatric disorders, including depression and addiction. This review will summarize recent findings on the medial (MHb) and lateral (LHb) habenula, their topographical projections, cell types, and functions. Additionally, we will discuss contemporary efforts that have uncovered novel molecular pathways and synaptic mechanisms with a focus on MHb-Interpeduncular nucleus (IPN) synapses. Finally, we will explore the potential interplay between the habenula's cholinergic and non-cholinergic components in coordinating related emotional and motivational behaviors, raising the possibility that these two pathways work together to provide balanced roles in reward prediction and aversion, rather than functioning independently.

A randomized controlled trial on the seeds of Sophora alopecuroides var. alopecuroides for the treatment of acute heroin withdrawal syndrome

BACKGROUND

and purpose: The seeds of Sophora alopecuroides var. alopecuroides have attenuated the acute opium withdrawal syndrome in humans. Therefore, the efficacy and safety of a standardized extract of the plant for the treatment of acute heroin withdrawal syndrome was evaluated in abstinent heroin addicts.

MATERIALS AND METHODS

The patients were randomized to take three 400 mg extract capsules (N = 50) or placebo (N = 50) once per day orally for eight days. The severity of withdrawal syndrome was assessed by the clinical opiate withdrawal scale (COWS) as the primary outcome measure at the baseline and on the days 3 and 8. The hepatic and renal functions and complete blood count were the secondary outcome measures tested at the baseline and end of the study.

RESULTS

The COWS score decreased in both groups after eight days, but the decrease was significantly higher in the experimental group (p < 0.001); the effect size of the decrease was 2.64. The groups had significant differences in the COWS scores on the days 3 and 8 (p < 0.001 for both). The extract had no significant effect on the other parameters. No side effect was noted.

CONCLUSION

The extract seems to alleviate acute heroin withdrawal syndrome safely.

Effectiveness of smoking cessation intervention in opioid-dependent male subjects on buprenorphine maintenance treatment: An open-label trial

Background

High prevalence (more than 80%) rates of tobacco smoking have been found both in, opioid-dependent subjects and among opioid-dependent subjects on opioid substitution treatment (OST) with buprenorphine or methadone.

Aim

We aimed to explore the efficacy of combined nicotine replacement therapy (NRT) and individual counseling (IC) when compared to NRT alone in subjects on OST with buprenorphine.

Methods

This study was carried out in a tertiary medical care center. It was an open-label randomized clinical trial. A total of 57 buprenorphine maintained smokers were recruited and randomized into two groups. They were assigned nicotine gum for 4 weeks plus either (1) a baseline IC session, and a second IC session after 1 week, or (2) simple advice to quit. In the first group, 31 subjects received NRT with IC and in the second group, 26 subjects received NRT plus simple advice to quit. The primary outcomes of this study were seven days point prevalence abstinence, biochemically confirmed by carbon monoxide (CO) breath analyzer, and reduction in smoking (mean no. of cigarettes or bidis/day). The smoking behavior during the 4 weeks follow-up period was assessed by the timeline follow-back (TLFB) method and confirmed by the CO breath analyzer.

Results

The group of subjects who received NRT with IC showed higher rates of smoking cessation at the end of treatment (51%) as compared to the NRT and simple advice group where smoking cessation rates were around 8% (P < 0.001).

Conclusion

A multi-component approach (pharmacotherapy and counseling) enhances treatment outcomes and enhances rates of abstinence from smoking.