Nicotine dependence predicts repeated use of prescribed opioids. Prospective population-based cohort study

Acute nicotine administration reduces the efficacy of punishment in curbing remifentanil consumption in a seeking-taking chain schedule of reinforcement

RATIONALE

Nicotine dependence is highly comorbid with opioid use disorders (OUDs). The use of nicotine-containing products increases the propensity to misuse prescription opioids and addressing both nicotine and opioid use simultaneously is more efficacious for treatment of OUDs than treating opioid use alone.

OBJECTIVES

Given this extreme comorbidity, further elucidation of the effects of nicotine as a factor in promoting vulnerability to development of OUDs is needed. Here, we sought to further explore the effects of nicotine administration on operant self-administration of remifentanil (RMF), a fast-acting synthetic µ-opioid receptor agonist, using a heterogenous seeking-taking chain schedule of reinforcement in unpunished and punished conditions.

METHODS

Male and female rats received nicotine (0.4 mg/kg) or saline prior to operant self-administration sessions. These sessions consisted of pressing a 'seeking' lever to gain access to a 'taking' lever that could be pressed for delivery of 3.2 µg/kg RMF. After acquisition, continued drug seeking/taking was punished through contingent delivery of foot-shock.

RESULTS

Nicotine, relative to saline, increased RMF consumption. Furthermore, nicotine treatment resulted in significantly higher seeking responses and cycles completed, and this effect became more pronounced during punished sessions as nicotine-treated rats suppressed RMF seeking significantly less than controls. Nicotine treatment functionally reduced the efficacy of foot-shock punishment as a deterrent of opioid-seeking.

CONCLUSIONS

Nicotine administration enhanced both appetitive and consummatory responding for RMF and engendered a punishment-insensitive phenotype for RMF that was less impacted by contingent administration of foot-shock punishment. These findings provide further support for the hypothesis that nicotine augments vulnerability for addiction-like behaviors for opioids.

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.

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.

The association between dual use of electronic nicotine products and illicit drugs with adverse cardiovascular and respiratory outcomes in a longitudinal analysis using the Population Assessment of Tobacco and Health (PATH) survey

Background

Drug use and electronic nicotine delivery systems (ENDS) are independently associated with increased risk of cardiovascular and respiratory outcomes. Literature on the association between the dual use of these key substances and potential health outcomes is limited.

Methods

We examined the association between dual use of ENDs and drugs (including heroin, methamphetamine, cocaine, painkillers, and misused stimulant medications) with adverse cardiovascular and respiratory outcomes in a longitudinal analysis using waves 1-5 from the Population Assessment of Tobacco and Health survey (2014-2018). Multivariable logistic regression with Generalized Estimating Equations was utilized.

Results

About 0.9% (n = 368) of respondents at wave 2 used both ENDS and drugs, 5.1% (n = 1,985) exclusively used ENDS, and 5.9% (n = 1,318) used drugs. Compared with people who do not use drugs, both those who used only ENDS (Adjusted Odds Ratio (AOR) 1.11 [95% CI 0.99-1.23], P = 0.07758) and those who used only drugs (AOR 1.36 [95% CI 1.15-1.60], P = 0.00027) were more likely to experience adverse respiratory conditions. Individuals who used drugs and ENDS compared to people who did not use drugs or ENDS had the largest odds of respiratory problems among all drug use category comparisons (AOR 1.52 [95% CI 1.20-1.93], P = 0.00054). Individuals who only used drugs had elevated odds of cardiovascular ailments compared to people who did not use drugs or ENDS (AOR 1.24 [95% CI 1.08-1.42], P = 0.00214) and compared to people who only used ENDS (AOR 1.22 [95% CI 1.04-1.42], P = 0.0117).

Conclusions

Inhaling electronic nicotine delivery systems and other substances may negatively affect the users' respiratory health.

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

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

Factors Associated With Pain Medication Use and the Relationship to Chiropractic Treatment Outcomes for Patients With Low Back and Neck Pain: A Cross-Sectional Study

OBJECTIVE

The study objectives were to identify baseline factors associated with pain medication use and determine any differences in chiropractic treatment outcomes in patients with low back pain (LBP) and neck pain (NP) depending on their use of pain medication.

METHODS

This cross-sectional, prospective outcomes study included 1077 adults with acute or chronic LBP and 845 adults with acute or chronic NP recruited from Swiss chiropractors in their offices within 4 years. Demographic data and the responses to the Patient's Global Impression of Change scale collected at 1 week, 1 month, 3 months, 6 months, and 1 year were analyzed with the χ2 test. Baseline pain and disability levels were measured using the numeric rating scale (NRS), Oswestry questionnaire for LBP, and Bournemouth questionnaire for patients with NP and analyzed with the Mann-Whitney U test between the 2 groups. To detect significant predictors of medication use at baseline, logistic regression analysis was performed.

RESULTS

Patients with acute LBP and NP were more likely than those with chronic pain to take pain medication (P < .001 LBP; P = .003 NP). Medication use was more likely with patients with radiculopathy (P < .001 LBP; P = .05 NP) who were smokers (P = .008 LBP; P = .024 NP) and those reporting below-average general health (P < .001 LBP and NP). Pain medication users had higher baseline pain (P < .001 LBP and NP) and disability (P < .001 LBP and NP) scores.

CONCLUSION

Patients with LBP and NP had significantly higher pain and disability levels at baseline, tended to have radiculopathy and poor health, were smokers, and presented during the acute phase. However, for this sample of patients, there were no differences in subjective improvement between users and non-users of pain medication for any data collection time point, which has management implications.

Acute nicotine treatment enhances compulsive-like remifentanil self-administration that persists despite contextual punishment

Opioid use disorder (OUD) and opioid-related deaths remain a significant public health crisis having reached epidemic status globally. OUDs are defined as chronic, relapsing conditions often characterized by compulsive drug seeking despite the deleterious consequences of drug taking. The use of nicotine-containing products has been linked to increased likelihood of prescription opioid misuse, and there exists a significant comorbidity between habitual nicotine use and opioid dependence. In rodent models, nicotine administration nearly doubles the amount of opioids taken in intravenous self-administration paradigms. Here, we examined the effect of acute systemic nicotine administration in male rats on responding for the synthetic opioid remifentanil (RMF) in a contextual punishment paradigm using either an exteroceptive punisher (foot-shock) or an interoceptive punisher (histamine). Nicotine administration, relative to saline, increased RMF intake in both unpunished and punished contexts, regardless of form of punishment, and resulted in significantly higher motivation to obtain RMF in the previously punished context, as measured by progressive ratio breakpoint. Additionally, regardless of context, nicotine-treated rats were slower to extinguish RMF responding following drug removal and displayed higher levels of cue-induced reinstatement than saline-treated controls. Furthermore, these data support that, compared with histamine adulteration, contingent foot-shock is a more potent form of punishment, as histamine punishment failed to support contextual discrimination between the unpunished and punished contexts. In contrast to RMF administration, augmentation of responding for an audiovisual cue by nicotine pretreatment was lost following contextual punishment. In conclusion, acute nicotine administration in adult male rats significantly enhances compulsive-like responding for RMF that persists despite contingent punishment of drug-directed responding.

Tobacco use severity in relation to opioid misuse and dependence among adult tobacco users with chronic pain: The moderating role of pain-related anxiety

The opioid epidemic is a significant public health crisis that is often linked to chronic pain management. One ensuing consequence of long-term opioid use for chronic pain is a high potential for opioid misuse and dependence. Although tobacco is commonly used among individuals with chronic pain, it is associated with an increased risk for opioid-related problems. Given the deleterious outcomes of tobacco use in the context of chronic pain, identifying individual difference factors involved in tobacco-opioid relations is of public health importance. Pain-related anxiety, or a tendency to respond to pain sensations with anxiety and fear, maybe an especially important mechanistic factor associated with the relationship between tobacco use severity and opioid misuse. Therefore, the current study examined the moderating role of pain-related anxiety on the relationship between tobacco use severity and opioid misuse and dependence. Participants were 258 tobacco-using adults who endorsed moderate to severe chronic pain and current use of an opioid medication (72.1% female, Mage = 37.19 years, SD = 10.17). Two hierarchical linear regression analyses were conducted to test main and interactive effects of tobacco use severity and pain-related anxiety for current opioid misuse and severity of opioid dependence. Results indicated a significant moderation effect, such that the relationship between tobacco use severity and opioid misuse and dependence was stronger among individuals with higher (but not lower) pain-related anxiety. These findings build upon the extant literature by demonstrating an interactive effect of tobacco use severity and pain-related anxiety in terms of opioid-related outcomes and suggest that current tobacco users with elevated levels of pain-related anxiety may be at increased risk for opioid misuse and dependence.

Prevalence and Childhood Precursors of Opioid Use in the Early Decades of Life

IMPORTANCE

Opioid use disorder and opioid deaths have increased dramatically in young adults in the US, but the age-related course or precursors to opioid use among young people are not fully understood.

OBJECTIVE

To document age-related changes in opioid use and study the childhood antecedents of opioid use by age 30 years in 6 domains of childhood risk: sociodemographic characteristics; school or peer problems; parental mental illness, drug problems, or legal involvement; substance use; psychiatric illness; and physical health.

DESIGN, SETTING, AND PARTICIPANTS

This community-representative prospective longitudinal cohort study assessed 1252 non-Hispanic White individuals and American Indian individuals in rural counties in the central Appalachia region of North Carolina from January 1993 to December 2015. Data were analyzed from January 2019 to January 2020.

EXPOSURES

Between ages 9 and 16 years, participants and their parents were interviewed up to 7 times using the Child and Adolescent Psychiatric Assessment and reported risk factors in 6 risk domains.

MAIN OUTCOMES AND MEASURES

Participants were assessed again at ages 19, 21, 25, and 30 years for nonheroin opioid use (any and weekly) and heroin use using the structured Young Adult Psychiatric Assessment.

RESULTS

Of 1252 participants, 342 (27%) were American Indian. By age 30 years, 322 participants had used a nonheroin opioid (24.2%; 95% CI, 21.8-26.5), 155 had used a nonheroin opioid weekly (8.8%; 95% CI, 7.2-10.3), and 95 had used heroin (6.6%; 95% CI, 5.2-7.9). Childhood risk markers for later opioid use included male sex, tobacco use, depression, conduct disorder, cannabis use, having peers exhibiting social deviance, parents with legal involvement, and elevated systemic inflammation. In final models, childhood tobacco use, depression, and cannabis use were most robustly associated with opioid use in young adulthood (ages 19 to 30 years). Chronic depression and dysthymia were strongly associated with any nonheroin opioid use (OR. 5.43; 95% CI, 2.35-12.55 and OR, 7.13; 95% CI, 1.99-25.60, respectively) and with weekly nonheroin opioid use (OR, 8.89; 95% CI, 3.61-21.93 and OR, 11.51; 95% CI, 3.05-42.72, respectively). Among young adults with opioid use, those with heroin use had the highest rates of childhood psychiatric disorders and comorbidities.

CONCLUSIONS AND RELEVANCE

Childhood tobacco use and chronic depression may be associated with impaired reward system functioning, which may increase young adults' vulnerability to opioid-associated euphoria. Preventing and treating early substance use and childhood mental illness may help prevent later opioid use.

Systemic nicotine enhances opioid self-administration and modulates the formation of opioid-associated memories partly through actions within the insular cortex

Habitual use of nicotine containing products increases propensity to misuse prescription opioids and its prevalence is substantially increased in individuals currently involved in opioid-treatment programs. Nicotine enhances self-administration of many classes of drugs in rodents, though evidence for direct effects on opioids is lacking. We sought to measure the effects of nicotine pretreatment on the reinforcing efficacy of opioids in both self-administration and contextual conditioning paradigms. First, we measured the effect of systemic nicotine pretreatment on self-administration of two opioids. Additionally, we measured the degree to which systemic nicotine pretreatment impacts the formation of morphine-associated contextual memories in conditioned taste avoidance and place preference paradigms. Given the involvement of the insula in the maintenance of substance abuse, its importance in nicotine addiction, and findings that insular inactivation impairs contextual drug conditioning, we examined whether nicotine administered directly to the insula could recapitulate the effects of systemic nicotine. We demonstrate that systemic nicotine pretreatment significantly enhances opioid self-administration and alters contextual conditioning. Furthermore, intra-insula nicotine similarly altered morphine contextual conditioning by blocking the formation of taste avoidance at all three morphine doses tested (5.0, 10, and 20 mg/kg), while shifting the dose–response curve of morphine in the place preference paradigm rightward. In conclusion, these data demonstrate that nicotine facilitates opioid intake and is partly acting within the insular cortex to obfuscate aversive opiate memories while potentiating approach to morphine-associated stimuli at higher doses.

Independent association of tobacco use with opioid use disorder in patients of European ancestry with chronic non-cancer pain

BACKGROUND

The harms associated with prescription opioid abuse have become a public health crisis. There is a need for evidence-based objective markers of the risk of opioid use disorder (OUD) in patients with pain receiving opioid treatment. The objective of this study was to evaluate the independent association of tobacco use and OUD in patients with chronic non-cancer pain.

METHODS

This cross-sectional naturalistic study evaluated 798 adults ≥ 18 years with chronic non-cancer pain treated with long-term opioid therapy (≥ 6 months) who either developed an OUD (cases, n = 216) or displayed no evidence of an OUD (controls, n = 582). The primary outcome was presence of OUD. In addition to current self-reported tobacco use (primary predictor), covariates included demographics, pain severity, and psychiatric history. Data were collected between November 2012 and September 2018.

RESULTS

Current tobacco use independently was strongly associated with OUD [odds ratio (OR) 14.0, 95 % confidence interval (CI) 9.5-20.6, p < 0.001], and this association remained significant after adjusting for other risk factors [adjusted odds ratio (aOR) 7.6, 95 % CI 4.8-12.2, p < 0.001]. Other factors associated independently with development of OUD included age, marital status, financial status, education and pain severity.

CONCLUSIONS AND RELEVANCE

Current tobacco use is significantly associated with OUD in patients with chronic pain receiving long-term opioid therapy.

Psycho-Social Correlates of Opioid Use Disorder among the US Adult Population: Evidence from the National Survey on Drug Use and Health, 2015-2018

The United States (US) has experienced an opioid epidemic over the last two decades. Drug overdose deaths increased by 21% from 2015 to 2016, with two-thirds of these deaths attributed to opioid use disorder (OUD). This study assessed the psycho-social correlates associated with OUD over 2015-2018 in the US. Methods: This study used data collected from 171,766 (weighted = 245,838,163) eligible non-institutionalized US adults in the pooled National Survey on Drug Use and Health from 2015-2018. Survey-weighted descriptive, bivariate, and multivariable analyses were performed to assess the psycho-social correlates of OUD. Results: About 0.85% of the respondents reported having OUD in the past year. About one-quarter (26.3%), one-sixth (14.8%), and half (47.3%) of the respondents with OUD reported alcohol, marijuana, and nicotine dependence, respectively. One-sixth (16.7%) had a criminal justice involvement history, and almost one-third (30.8%) experienced a major depressive episode (MDE) in the past year. In multivariable analysis, ≤64 years, White race, male gender, lower educational attainment, unemployment, large metro area residence, history of alcohol, marijuana, nicotine use disorder, history of criminal justice involvement, and MDE in previous year were associated with higher odds of OUD. In contrast, being married, non-Hispanic African American, non-Hispanic Other, and Hispanic ethnicity, good physical health, private health insurance, and higher risk perception about addictive substance use were associated with lower odds of OUD. Conclusions: OUD is more prevalent among certain sociodemographic groups in the US. Targeted interventions focusing on young, White, unmarried, male, and uninsured/Medicaid/Medicare populations should be implemented to reduce the OUD.

Cigarette smoking, prescription opioid use and misuse among young adults: An exploratory analysis

Young adults have the highest prevalence of misuse of prescription opioids. In 2016, 7.1% of 18- to 25-year-olds reported misuse, meaning use other than as prescribed. While smoking is known to be associated with opioid use, to our knowledge no study has examined the relationships between smoking, prescribed use of opioids, and opioid misuse in young adults at the population level. Online survey data were collected in spring 2018 from a nationally representative sample of 18-25-year-olds from the Truth Longitudinal Cohort (N = 10,502). Respondents self-reported cigarette smoking, and both lifetime and recent (past 6-month) prescribed use and misuse of opioids. Generalized ordered logistic regression modeling was used to determine associations between cigarette smoking and recent prescribed use and misuse while controlling for demographic characteristics, other substance use, sensation seeking, and mental health status. Overall, 61.0% of respondents reported lifetime prescribed use of opioids and 16% reported recent prescribed use. Lifetime misuse was reported by 19.4%, with 7.8% reporting recent misuse. Together, the models revealed a graded relationship, with current smokers having higher odds of both prescribed use and misuse, never smokers having lowest odds of use or misuse, and ever smokers, those who had smoked but not in the past 30 days, falling between current and never smokers. Findings indicate a clear association between smoking and use of opioids even after accounting for a strong association between prescribed use and misuse among young adults.

Enhancement of Opioid Antinociception by Nicotine

Nicotine can produce antinociception in preclinical pain models; however, the ability of nicotine to augment the antinociceptive effects of opioid agonists has not been investigated. The present experiments were conducted to determine how nicotine modifies the effects of opioid agonists differing in efficacy. Male squirrel monkeys responded for the delivery of milk under a fixed ratio 10 schedule of reinforcement. During the 30-second timeout period following each milk delivery, the subject's tail was immersed in 35, 50, 52, or 55°C water, and the latency to remove the tail was recorded. Dose-response functions for tail-withdrawal latency and operant performance were determined for fentanyl, oxycodone, buprenorphine, and nalbuphine alone and after treatment with nicotine. Excepting nalbuphine, all opioids produced dose-related disruptions in food-maintained responding and increases in tail-withdrawal latency at each water temperature. Nicotine did not exacerbate the behaviorally disruptive effects of the μ-opioids on operant performance but produced a significant mecamylamine-sensitive enhancement of the antinociceptive potency of each opioid. Failure of arecoline to augment the antinociceptive effects of oxycodone and antagonism by mecamylamine suggests this nicotine-induced augmentation of prescription opioid antinociception was nicotinic acetylcholine receptor (nAChR) mediated. This was reflected in leftward shifts in the antinociceptive dose-response curve of each opioid, ranging from 2- to 7-fold increases in the potency of oxycodone across all water temperatures to an approximately 70-fold leftward shift in the antinociceptive dose-response curve of nalbuphine at the lower and intermediate water temperatures. These results suggest that nicotine may enhance μ-opioid antinociceptive effects without concomitantly exacerbating their behaviorally disruptive effects. SIGNIFICANCE STATEMENT: Prescription opioids remain the most effective pain-management pharmacotherapeutics but are limited by their adverse effects. The present results indicate that nicotine enhances antinociceptive effects of various opioid agonists in nonhuman primates without increasing their disruptive effects on operant performance. These results suggest that nicotine might function as an opioid adjuvant for pain management by enabling decreased clinically effective analgesic doses of prescription opioids without exacerbating their adverse behavioral effects.

Association between tobacco smoking and opioid use: A meta-analysis

BACKGROUND

Tobacco smoking has been shown to be a major risk factor for opioid use and opioid use disorders in several observational studies; however, the results are inconsistent. Thus, this systematic review and meta-analysis of observational studies was conducted to investigate the association between smoking behavior and opioid use and opioid use disorders.

METHODS

A systematic literature search of relevant keywords was done in Medline, Embase, Scopus, Web of Science, and Google Scholar up to October 2017. The reference lists of retrieved articles were also examined for inclusion. While random effects meta-analysis was used, pooled odds ratio (OR) and 95% confidence intervals were calculated using Der-Simonian and Laird method, taking into account conceptual heterogeneity. Subgroup analyses were performed using participants and studies' characteristics to assess the sources of heterogeneity.

RESULTS

Ten eligible observational studies (6 cohorts and 4 population-based cross sectional studies), with 175,063 participants, were identified. The pooled OR of opioid use disorders was 8.23 (95% CI: 3.07-22.09) for current smokers compared to nonsmokers; pooled OR for opioid use was 2.51 (95% CI: 1.91-3.28). Opioid use or opioid use disorders were positively associated with earlier age at onset of smoking (pooled OR = 1.66; 95% CI: 1.28-2.16).

CONCLUSIONS

The results of this meta-analysis confirmed that tobacco smoking is associated with opioid use and opioid use disorders development. This conclusion has an important public health message for areas with high smoking prevalence and high opioid use and opioid use disorders incidence.

Rat brain CYP2D activity alters in vivo central oxycodone metabolism, levels and resulting analgesia

Oxycodone is metabolized by CYP2D to oxymorphone. Despite oxymorphone being a more potent opioid-receptor agonist, its contribution to oxycodone analgesia may be minor because of low peripheral production, low blood-brain barrier permeability and central nervous system efflux. CYP2D metabolism within the brain may contribute to variation in central oxycodone and oxymorphone levels, thereby affecting analgesia. Brain CYP2D expression and activity are subject to exogenous regulation; nicotine induces rat brain, but not liver, CYP2D consistent with higher brain CYP2D in smokers. We assessed the role of rat brain CYP2D in orally administered oxycodone metabolism (in vivo brain microdialysis) and analgesia (tail-flick test) by inhibiting brain CYP2D selectively with intracerebroventricular propranolol (mechanism-based inhibitor) and inducing brain CYP2D with nicotine. Inhibiting brain CYP2D increased brain oxycodone levels (1.8-fold; P < 0.03) and analgesia (1.5-fold AUC0-60 ; P < 0.001) after oxycodone, while inducing brain CYP2D increased brain oxymorphone levels (4.6-fold; P < 0.001) and decreased analgesia (0.8-fold; P < 0.02). Inhibiting the induced brain CYP2D reversed the change in oxycodone levels (1.2-fold; P > 0.1) and analgesia (1.1-fold; P > 0.3). Brain, but not plasma, metabolic ratios were affected by pre-treatments. Peak analgesia was inversely correlated with ex vivo brain (P < 0.003), but not hepatic (P > 0.9), CYP2D activity. Altering brain CYP2D did not affect analgesia from oral oxymorphone (P > 0.9 for AUC0-60 across all groups), which is not a CYP2D substrate. Thus, brain CYP2D metabolism alters local oxycodone levels and response, suggesting that people with increased brain CYP2D activity may have reduced oxycodone response. Factors that alter individual oxycodone response may be useful for optimizing treatment and minimizing abuse liability.

The association of tobacco use with prescription of muscle relaxants, benzodiazepines, and opioid analgesics for non-cancer pain

BACKGROUND AND OBJECTIVES

Tobacco use and co-prescription of sedative hypnotics are risk factors for misuse of prescribed opioids among patients with non-cancer pain. However, the association between tobacco use and these co-prescriptions has not been clarified. We aimed to assess differences in the prescription and co-prescription rates of opioid analgesics with muscle relaxants and/or benzodiazepines between tobacco users and non-users.

METHODS

Visit data were obtained from the 2006 to 2009 National Ambulatory Medical Care Survey, an annual cross-sectional survey of visits to office-based physicians in outpatient settings in the United States. Our sample patients were aged ≥18 years and diagnosed with non-cancer back and neck pain. The χ² test and multiple logistic regression analysis were used to assess bivariate and multivariate associations between prescription or co-prescription rates and tobacco use status.

RESULTS

We analyzed a total of 114,199,536 weighted visits (unweighted number: 3,521). Significant odds ratios (ORs) of tobacco users (vs non-users) for medical prescriptions were as follows: opioid analgesics, OR 2.14, 95% confidence interval (CI) 1.64-2.80; muscle relaxants and opioid analgesics, OR 2.57, 95%CI 1.76-3.74; benzodiazepines and opioid analgesics, OR 3.66, 95%CI 2.11-6.35, and muscle relaxants, benzodiazepines, and opioid analgesics, OR 7.02, 95%CI 2.98-16.57.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

Tobacco users were more likely to receive prescriptions for opioid analgesics with muscle relaxants and/or benzodiazepines than non-users. Healthcare professionals need to limit co-prescription of opioid analgesics with muscle relaxants and/or benzodiazepines among tobacco users and provide a comprehensive approach to pain management. (Am J Addict 2019;XX:1-8).

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.

Marijuana and Prescription Pain Reliever Use among Cigarette Smokers

Due to marijuana's analgesic effects and its growing national legal status, it is likely that marijuana's rising prevalence will impact prescription pain reliever (PPR) use. The present study investigates the relationship between marijuana and PPR use among U.S. adult current cigarette smokers. Data were analyzed from the Tobacco and Attitudes Beliefs Survey II, with 348 current cigarette smokers, aged 24-88. Logistic regression was used to examine the likelihood of current (past 30 days) PPR use by marijuana use (never, ever, and current) among cigarette smokers. Among PPR users (N = 76), we also investigated whether marijuana use frequency predicted current PPR use. Compared to never marijuana users, participants were more likely to report past 30-day PPR use if they have ever used marijuana (AOR: 2.58, 95% CI: 1.51-4.43) or have used marijuana in the past 30 days (AOR: 3.38, CI: 1.76-6.49). No significant relationship was found between marijuana use frequency and PPR use. Thus, in this sample of adult cigarette smokers, past and current marijuana users were two to three times more likely to report PPR use than never marijuana users. These findings can help inform policymakers and healthcare providers in their fight against the opioid epidemic.

Cigarette Smoking Status and Receipt of an Opioid Prescription Among Veterans of Recent Wars

Objective

Cigarette smokers seeking treatment for chronic pain have higher rates of opioid use than nonsmokers. This study aims to examine whether veterans of Operations Enduring Freedom/Iraqi Freedom/New Dawn (OEF/OIF/OND) who smoke are more likely to receive an opioid prescription than nonsmokers, adjusting for current pain intensity.

Design

Cross-sectional analysis of a cohort study of OEF/OIF/OND veterans who had at least one visit to a Veterans Health Administration primary care clinic between 2001 and 2012.

Methods

Smoking status was defined as current, former, and never. Current pain intensity (+/- 30 days of smoking status), based on the 0-10 numeric rating scale, was categorized as no pain/mild (0-3) and moderate/severe (4-10). Opioid receipt was defined as at least one prescription filled +/- 30 days of smoking status.

Results

We identified 406,954 OEF/OIF/OND veterans: The mean age was 30 years, 12.5% were women (n = 50,988), 66.3% reported no pain or mild pain intensity, 33.7% reported moderate or severe pain intensity, 37.2% were current smokers, and 16% were former smokers. Overall, 33,960 (8.3%) veterans received one or more opioid prescription. Current smoking (odds ratio [OR] = 1.56, 95% confidence interval [CI] = 1.52-1.61) and former smoking (OR = 1.27, 95% CI = 1.22-1.32) were associated with a higher likelihood of receipt of an opioid prescription compared with never smoking, after controlling for other covariates.

Conclusions

We found an association between smoking status and receipt of an opioid prescription. The effect was stronger for current smokers than former smokers, highlighting the need to determine whether smoking cessation is associated with a reduction in opioid use among veterans.

Understanding the demand side of the prescription opioid epidemic: Does the initial source of opioids matter?

BACKGROUND

These studies were carried out to examine whether the onset and progression of an opioid substance use disorder (SUD) differed in those who first used opioids to get "high" compared to those who received a prescription from a doctor to relieve pain (Non-Rx vs. Rx groups, respectively).

METHODS

A subset of patients (N=214) from an ongoing larger study of patients entering one of 125 drug treatment programs for opioid use disorder across the country agreed to give up their anonymity and participate in structured and open-ended online interviews examining drug abuse patterns.

RESULTS

With the exception that the Non-Rx group began their opioid abuse at a younger age than the Rx group and more quickly evolved from initial exposure to regular opioid abuse, there were relatively few differences in the characteristics, patterns and trajectories of opioid abuse. The vast majority of patients in both groups, most of whom had serious, antecedent psychiatric disorders, indicated that they used opioids to self-medicate psychological problems (67-73%) and/or stated that opioids provided a means to "escape" from the stresses of everyday life (79-85%). As the SUD progressed, for many individuals any "positive" attributes of opioids waned and avoidance of withdrawal became the overriding concern, often serving as the impetus for treatment.

CONCLUSIONS

Our results suggest that self-treatment of co-morbid psychiatric disturbances is a powerful motivating force to initiate and sustain abuse of opioids and that the initial source of drugs-a prescription or experimentation-is largely irrelevant in the progression to a SUD.

Guideline for Prescribing Opioids to Treat Pain in Injured Workers

Recently, there has been a dramatic increase in the use of opioids to treat chronic noncancer pain. Opioids are also being prescribed in stronger potencies and larger doses for musculoskeletal injuries. In some cases, the use of opioids for work-related injuries may actually increase the likelihood of disability. Chronic opioid use is associated with increased risk for overdose morbidity and mortality and other nonfatal adverse outcomes. The risk of dependence and addiction is much more common than previously thought. This guideline provides recommendations for prudent opioid prescribing and addresses issues critical to the care and rehabilitation of injured workers.

Opioid Analgesics and Nicotine: More Than Blowing Smoke

Practitioners are highly likely to encounter patients with concurrent use of nicotine products and opioid analgesics. Smokers present with more severe and extended chronic pain outcomes and have a higher frequency of prescription opioid use. Current tobacco smoking is a strong predictor of risk for nonmedical use of prescription opioids. Opioid and nicotinic-cholinergic neurotransmitter systems interact in important ways to modulate opioid and nicotine effects: dopamine release induced by nicotine is dependent on facilitation by the opioid system, and the nicotinic-acetylcholine system modulates self-administration of several classes of abused drugs-including opioids. Nicotine can serve as a prime for the use of other drugs, which in the case of the opioid system may be bidirectional. Opioids and compounds in tobacco, including nicotine, are metabolized by the cytochrome P450 enzyme system, but the metabolism of opioids and tobacco products can be complicated. Accordingly, drug interactions are possible but not always clear. Because of these issues, asking about nicotine use in patients taking opioids for pain is recommended. When assessing patient tobacco use, practitioners should also obtain information on products other than cigarettes, such as cigars, pipes, smokeless tobacco, and electronic nicotine delivery systems (ENDS, or e-cigarettes). There are multiple forms of behavioral therapy and pharmacotherapy available to assist patients with smoking cessation, and opioid agonist maintenance and pain clinics represent underutilized opportunities for nicotine intervention programs.

Gene network analysis shows immune-signaling and ERK1/2 as novel genetic markers for multiple addiction phenotypes: alcohol, smoking and opioid addiction

Background

Addictions to alcohol and tobacco, known risk factors for cancer, are complex heritable disorders. Addictive behaviors have a bidirectional relationship with pain. We hypothesize that the associations between alcohol, smoking, and opioid addiction observed in cancer patients have a genetic basis. Therefore, using bioinformatics tools, we explored the underlying genetic basis and identified new candidate genes and common biological pathways for smoking, alcohol, and opioid addiction.

Results

Literature search showed 56 genes associated with alcohol, smoking and opioid addiction. Using Core Analysis function in Ingenuity Pathway Analysis software, we found that ERK1/2 was strongly interconnected across all three addiction networks. Genes involved in immune signaling pathways were shown across all three networks. Connect function from IPA My Pathway toolbox showed that DRD2 is the gene common to both the list of genetic variations associated with all three addiction phenotypes and the components of the brain neuronal signaling network involved in substance addiction. The top canonical pathways associated with the 56 genes were: 1) calcium signaling, 2) GPCR signaling, 3) cAMP-mediated signaling, 4) GABA receptor signaling, and 5) G-alpha i signaling.

Conlusions

Cancer patients are often prescribed opioids for cancer pain thus increasing their risk for opioid abuse and addiction. Our findings provide candidate genes and biological pathways underlying addiction phenotypes, which may be future targets for treatment of addiction. Further study of the variations of the candidate genes could allow physicians to make more informed decisions when treating cancer pain with opioid analgesics.

Electronic supplementary material

The online version of this article (doi:10.1186/s12918-015-0167-x) contains supplementary material, which is available to authorized users.

Nicotine Increases Codeine Analgesia Through the Induction of Brain CYP2D and Central Activation of Codeine to Morphine

CYP2D metabolically activates codeine to morphine, which is required for codeine analgesia. Permeability across the blood-brain barrier, and active efflux, suggests that initial morphine in the brain after codeine is due to brain CYP2D metabolism. Human CYP2D is higher in the brains, but not in the livers, of smokers and 7-day nicotine treatment induces rat brain, but not hepatic, CYP2D. The role of nicotine-induced rat brain CYP2D in the central metabolic activation of peripherally administered codeine and resulting analgesia was investigated. Rats received 7-day nicotine (1 mg/kg subcutaneously) and/or a single propranolol (CYP2D mechanism-based inhibitor; 20 μg intracerebroventricularly) pretreatment, and then were tested for analgesia and drug levels following codeine (20 mg/kg intraperitoneally) or morphine (3.5 mg/kg intraperitoneally), matched for peak analgesia. Nicotine increased codeine analgesia (1.59X AUC(0-30 min) vs vehicle; p<0.001), while propranolol decreased analgesia (0.56X; p<0.05); co-pretreatment was similar to vehicle controls (1.23X; p>0.1). Nicotine increased, while propranolol decreased, brain, but not plasma, morphine levels, and analgesia correlated with brain (p<0.02), but not plasma (p>0.4), morphine levels after codeine. Pretreatments did not alter baseline or morphine analgesia. Here we show that brain CYP2D alters drug response despite the presence of substantial first-pass metabolism of codeine and further that nicotine induction of brain CYP2D increases codeine response in vivo. Thus variation in brain CYP2D activity, due to genetics or environment, may contribute to individual differences in response to centrally acting substrates. Exposure to nicotine may increase central drug metabolism, not detected peripherally, contributing to altered drug efficacy, onset time, and/or abuse liability.

Tobacco Smoking, Nicotine Dependence, and Patterns of Prescription Opioid Misuse: Results From a Nationally Representative Sample

INTRODUCTION

The misuse of prescription opioid medications is a growing public health crisis. Given evidence of complex nicotine-opioid interactions, and initial support for the role of smoking status as a risk factor for prescription opioid misuse, a more detailed analysis of how current and historical patterns of smoking may influence misuse of prescription opioids is warranted.

METHODS

The current study is the first to test whether varying levels of current/historical smoking (current daily, current intermittent, former daily, never) and indices of smoking heaviness/nicotine dependence may be associated with greater likelihood of past-year prescription opioid misuse in the general population. Data were derived from the National Survey on Drug Use and Health (N = 24,348).

RESULTS

Consistent with hypotheses, after accounting for sociodemographic factors and major depressive/alcohol use disorders, both daily and intermittent smokers were greater than 3 times more likely to report past-year nonmedical prescription opioid use than were never smokers. In addition, daily smokers were observed to be nearly 5 times more likely, and intermittent smokers were nearly 3 times more likely, to have met past-year abuse/dependence criteria, relative to never smokers. Results further revealed positive associations between various indices of smoking heaviness/nicotine dependence and opioid medication misuse, and these findings remained largely consistent when analyses were stratified by gender.

CONCLUSIONS

These findings indicate that smokers are not a homogeneous group with regard to risk for opioid misuse, and support the utility of comprehensive smoking assessment in the context of opioid-based treatment/tapering.

Nicotine dependence among clients receiving publicly funded substance abuse treatment

BACKGROUND

Smoking and nicotine dependence (ND) are prevalent among substance abusers but little is known about characteristics of ND in this population. This information would help identify those most in need of smoking cessation programs. This study evaluated the associations of socio-demographic, tobacco- and substance use-related, and health/mental health factors to ND in adults receiving publicly funded substance abuse treatment in Tennessee.

METHODS

All Tennessee residents who received federal block grant-funded substance abuse treatment during July-December, 2004 were invited to participate in a 6 month post-intake telephone follow-up interview. Socio-demographic characteristics, perceived health and mental health, tobacco use history and patterns, and ND, assessed by the Fagerstrom Test of Nicotine Dependence (FTND), were obtained at follow-up. Alcohol and illicit drug use and smoking status prior to treatment were assessed at intake. This paper analyzes data for 855 clients who were current cigarette smokers at both intake and follow-up.

RESULTS

Sixty three percent of smokers were ND (FTND score ≥ 4). Correlates of ND included older age, poorer self-rated overall health, earlier age of onset of cigarette smoking and substance abuse, fewer smoking quit attempts in past year, single substance use (alcohol or illicit drug, vs. multiple substances) at intake, use of opiates/narcotics and sedatives, and past month self-reported depression.

CONCLUSION

ND was highly prevalent and correlated with specific types and patterns of substance abuse and depression. These results suggest that intensive smoking cessation interventions, involving behavioral support, pharmacotherapy, and mood management, are needed to effectively assist this population.

Is smoking associated with alcohol-drug dependence in patients with pain and chronic pain patients? An evidence-based structured review

OBJECTIVE

The objective of this study was to determine if there is consistent evidence for smoking to be considered a red flag for development of opioid dependence during opioid exposure in patients with pain and chronic pain patients (CPPs).

METHODS

Six hundred and twenty-three references were found that addressed the areas of smoking, pain, and drug-alcohol dependence. Fifteen studies remained after exclusion criteria were applied and sorted into four groupings addressing four hypotheses: patients with pain and CPPs who smoke are more likely than their nonsmoking counterparts to use opioids, require higher opioid doses, be drug-alcohol dependent, and demonstrate aberrant drug-taking behaviors (ADTBs). Each study was characterized by the type of study it represented according to the Agency for Health Care Policy and Research (AHCPR) guidelines and independently rated by two raters according to 13 quality criteria to generate a quality score. The percentage of studies in each grouping supporting/not supporting each hypothesis was calculated. The strength and consistency of the evidence in each grouping was rated by the AHCPR guidelines.

RESULTS

In each grouping, 100% of the studies supported the hypothesis for that grouping. The strength and consistency of the evidence was rated as A (consistent multiple studies) for the first hypothesis and as B (generally consistent) for the other.

CONCLUSIONS

There is limited consistent indirect evidence that smoking status in patients with pain and CPPs is associated with alcohol-drug and opioid dependence. Smoking status could be a red flag for opioid-dependence development on opioid exposure.

Managing co-occurring substance use and pain disorders

The safest pain treatment strategy for an individual at risk or recovering from addiction is a nonopioid and benzodiazepine-free approach. If an opioid treatment is necessary, the extent of the risk can be stratified by the use of a biopsychosocial assessment and opioid screening tools. Individuals at high risk should have the greatest amount of structure and monitoring. A written informed consent and treatment agreement can provide a framework for the patient and the patient’s family, as well as the clinician. The structure of treatment should specify only that one prescribing physician will write a limited supply of opioids, without refills, until the analgesic efficacy, adverse events, and goals for functional restoration can be assessed. An additional recommendation is that prescriptions should be filled at the same pharmacy with no refill by phone or opportunity for replacement because of loss, damage, or stolen medications. Additionally, random urine drug screens and PDMP reports obtained will help determine if the patient is taking other substances, as well as monitor the patient’s medication use patterns. It is important to assess for risk factors in treating chronic pain with opioids; clinicians need to have a realistic appreciation of the resources available to them and the types of patients that can be managed in their practice. Chronic pain treatment with opioids should not be undertaken in patients who are currently addicted to illicit substances or alcohol. With the support of family and friends, ideally the patient can be motivated to participate in an intensive substance abuse treatment. In patients without an immediate risk, precautionary steps should be taken when prescribing opioids. Clinicians and patients need to review the risk factors for opioid-related problems including younger age, benzodiazepine use, and comorbid conditions such as depression, anxiety, and heavy smoking. Both the provider and the patient need a personal investment in the treatment plan and protocol to increase the safety of opioid treatment. New medications and treatment monitoring are being developed to provide maximal relief for the patient while protecting the public health. The optimal ingredients for safe opioid treatment include a strong provider-patient relationship and clinician training in the assessment and treatment of addiction and pain.

Patterns and correlates of prescription opioid use in OEF/OIF veterans with chronic noncancer pain

OBJECTIVES

Little is known about the treatment Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) veterans receive for chronic noncancer pain (CNCP). We sought to describe the prevalence of prescription opioid use, types, and doses of opioids received and to identify correlates of receiving prescription opioids for CNCP among OEF/OIF veterans.

DESIGN

Retrospective review of Veterans Affairs (VA) administrative data.

SETTING

Ambulatory clinics within a VA regional health care network.

PATIENTS

OEF/OIF veterans who had at least three elevated pain screening scores within a 12-month period in 2008. Within this group, those prescribed opioids (N = 485) over the next 12 months were compared with those not prescribed opioids (N = 277). In addition, patients receiving opioids short term (<90 days, N = 284) were compared with patients receiving them long term (≥90 consecutive days, N = 201).

RESULTS

Of 762 OEF/OIF veterans with CNCP, 64% were prescribed at least one opioid medication over the 12 months following their index dates. Of those prescribed an opioid, 59% were prescribed opioids short term and 41% were prescribed opioids long term. The average morphine-equivalent opioid dose for short-term users was 23.7 mg (standard deviation [SD] = 20.5) compared with 40.8 mg (SD = 36.1) for long-term users (P < 0.001). Fifty-one percent of long-term opioid users were prescribed short-acting opioids only, and one-third were also prescribed sedative hypnotics. In adjusted analyses, diagnoses of low back pain, migraine headache, posttraumatic stress disorder, and nicotine use disorder were associated with an increased likelihood of receiving an opioid prescription.

CONCLUSION

Prescription opioid use is common among OEF/OIF veterans with CNCP and is associated with several pain diagnoses and medical conditions.

Patterns of prescription opioid abuse and comorbidity in an aging treatment population

Very little is known about the impact of age and gender on drug abuse treatment needs. To examine this, we recruited 2,573 opioid-dependent patients, aged from 18 to 75 years, entering treatment across the country from 2008 to 2010 to complete a self-administered survey examining drug use histories and the extent of comorbid psychiatric and physical disorders. Moderate to very severe pain and psychiatric disorders, including polysubstance abuse, were present in a significant fraction of 18- to 24-year-olds, but their severity grew exponentially as a function of age: 75% of those older than 45 years had debilitating pain and psychiatric problems. Women had more pain than men and much worse psychiatric issues in all age groups. Our results indicate that a "one-size-fits-all" approach to prevention, intervention, and treatment of opioid abuse that ignores the shifting needs of opioid-abusing men and women as they age is destined to fail.