Gender difference in prescription opioid abuse: A focus on oxycodone and hydrocodone

Oxycodone self-administration and reinstatement in male and female squirrel monkeys: Effects of alternative reinforcer availability

The use of non-drug alternative reinforcers has long been utilized as a component of therapeutic interventions for the management of substance use disorder; however, the conditions under which alternative reinforcers are most effective are not well characterized. This study evaluated the impact of varying the magnitude of an alternative reinforcer on oxycodone self-administration and reinstatement in male and female squirrel monkeys. Subjects (n=4/sex) were trained under concurrent second-order schedules of reinforcement for intravenous oxycodone (0.001-0.1mg/kg/inj) on one lever, and sweetened condensed milk (5, 10, 20, 30% in water) on another. Oxycodone-primed reinstatement was evaluated by administering 0.32mg/kg oxycodone prior to sessions in which saline was available on the drug-paired lever. During oxycodone self-administration sessions, milk availability decreased oxycodone self-administration and preference in a concentration-dependent manner; low milk concentrations were more effective at decreasing oxycodone’s reinforcing potency in males. During reinstatement tests, milk significantly attenuated oxycodone-primed responding in both males and females; low milk concentrations were more effective at decreasing the priming effects of oxycodone in females. That alternative reinforcers differentially impacted self-administration and reinstatement in a sex-dependent manner suggests that treatment strategies that utilize alternative reinforcers may be more effective in males or females depending on when they are implemented.

Sex Differences in Oxycodone/Naloxone vs. Tapentadol in Chronic Non-Cancer Pain: An Observational Real-World Study

Despite the large body of research on sex differences in pain, there is a lack of translation to real-world pain management. Our aim was to analyse the sex differences in the analgesic response to oxycodone/naloxone (OXN) and tapentadol (TAP), in comparison with other opioids (OPO) commonly prescribed for chronic non-cancer pain (CNCP). An observational and cross-sectional study was conducted on ambulatory CNCP patients (n = 571). Sociodemographic, clinical (pain intensity, relief, and quality of life), safety (adverse events (AEs), adverse drug reactions), hospital frequentations and pharmacological (morphine equivalent daily dose (MEDD)) variables were collected. Multiple linear regressions were carried out to assess the association between sex and outcomes. Sex differences were observed, with lower female tolerability and higher hospital frequentation, especially in the OXN group (OR AEs report = 2.8 [1.8−4.4], p < 0.001). Here, females showed higher hospital use (23% hospital admission, 30% prescription change, p < 0.05), requiring a higher MEDD (127 ± 103 mg/day, p < 0.05), compared to OXN men. Regardless of the opioid group, CNCP women were significantly older than men (three years), with significantly higher benzodiazepine use (OR = 1.6 [1.1−2.3]), more constipation (OR = 1.34 [0.93−1.90]) and headache (OR = 1.45 [0.99−2.13]) AEs, than men who were more likely to refer sexual dysfunction (OR = 2.77 [1.53−5.01]), and loss of libido (OR = 1.93 [1.22−3.04]). Sex-differences were found related to poorer female drug tolerability and higher hospital resources, even worst in OXN female users. Other differences related to older female ages and benzodiazepine prescription, need to be further analysed from a gender perspective.

CYP2D6 phenotypes and opioid metabolism: the path to personalized analgesia

INTRODUCTION

Opioids play a fundamental role in chronic pain, especially considering when 1 of 5 Europeans adults, even more in older females, suffer from it. However, half of them do not reach an adequate pain relief. Could pharmacogenomics help to choose the most appropriate analgesic drug?

AREAS COVERED

The objective of the present narrative review was to assess the influence of cytochrome P450 2D6 (CYP2D6) phenotypes on pain relief, analgesic tolerability, and potential opioid misuse. Until December 2021, a literature search was conducted through the MEDLINE, PubMed database, including papers from the last 10 years. CYP2D6 plays a major role in metabolism that directly impacts on opioid (tramadol, codeine, or oxycodone) concentration with differences between sexes, with a female trend toward poorer pain control. In fact, CYP2D6 gene variants are the most actionable to be translated into clinical practice according to regulatory drug agencies and international guidelines.

EXPERT OPINION

CYP2D6 genotype can influence opioids' pharmacokinetics, effectiveness, side effects, and average opioid dose. This knowledge needs to be incorporated in pain management. Environmental factors, psychological together with genetic factors, under a sex perspective, must be considered when you are selecting the most personalized pain therapy for your patients.

Mitigating the opioid crisis for the lower extremity provider opioid stewardship programs

Opioids are an effective form of analgesia for pain treatment. Over prescribing of opioids agents have becom;1;e detrimental to the United States' public health. One of the most difficult challenges for any prescriber is to balance the potential benefits versus the potential risks of opioid prescribing. Addressing the opioid crisis requires an interprofessional team approach. The utilization of an opioid stewardship program provides the necessary frame work to identify gaps in the in quality and development in the implementation of a change of long standing opioid culture and practice. These programs address opioid prescribing, treatment for opioid use disorder, educational initiatives, and the use of information technology. A few acronyms have been created to assist providers to guide them when prescribing opioids. The purpose of this article is to explore the central theme of responsible opioid pain management. It will introduce, define, and defend with clinical base evidence a proposed acronym "MORPHINE" to assist and help shape prescription opioid strategies used for lower extremity pain. Implications for practicing lower extremity providers need to acknowledge the potential harm that prescribing opioids may cause to their patients. Opioid stewardship principles should become a priority in podiatric medicine and podiatric surgery.

Sex Differences in Substance Use and Misuse: A Toxicology Investigators' Consortium (ToxIC) Registry Analysis

Background

Variations between male and female populations are previously reported in classes of harmfully used/misused drugs, severity of substance use disorder and risk of relapse. The aim of this study was to provide a review of bedside medical toxicologist managed, sex-specific poisonings in adults that present with harmful drug use/misuse.

Methods

ToxIC Registry cases ≥19 and ≤65 years old, with harmful drug use or misuse during the timeframe June 2010–December 2016, were studied. Demographics, primary agents of toxic exposure, administration route and complications were analyzed. Descriptive methods were used in the analysis.

Results

The database included 51,440 cases. Of these, 3426 cases were analyzed in which the primary reason for the encounter was harmful substance use/misuse. Females were found to harmfully use/misuse pharmaceutical drugs (N=806, 65.6%) more than nonpharmaceutical drugs (N=423, 34.4%). Males more frequently used nonpharmaceutical drugs (N=1189, 54.1%) than pharmaceutical drugs (1008, 45.9%). Analgesics were used by females (N= 215, 18.2%) and males (N=137, 6.6%). Sedative hypnotics were used by females (N=165, 14%) and males (N=160, 7.8%). Psychoactive agents were used by males (N=325, 15.8%) and females (N=67, 5.7%). Sympathomimetics were used by males (N=381, 18.5%) and females (N=151, 12.8%). The majority of both male and female participants, 1712 (57.9%), utilized an oral route of administration. However, 312 (16.5%) of males utilized inhalation vs 73 (6.8%) of females inhaled their substance.

Conclusion

There were sex-specific differences among patients evaluated for harmful substance use/misuse by toxicologists. Considering these differences in regards to management and preventive approaches may be indicated.

Impact of CYP2D6, CYP3A5, and ABCB1 Polymorphisms on Plasma Concentrations of Donepezil and Its Metabolite in Patients With Alzheimer Disease

BACKGROUND

Donepezil is one of the most commonly prescribed drugs for the treatment of Alzheimer disease. It is predominantly metabolized through CYP2D6 and to a lesser extent by CYP3A4/5. There are conflicting reports regarding the influence of CYP2D6, CYP3A5, and ABCB1 polymorphisms on the plasma concentration of donepezil. This study investigated the influence of these polymorphisms and sex on the plasma concentrations of donepezil and its active metabolite, 6-O-desmethyl donepezil (6ODD), in 47 patients with Alzheimer disease.

METHODS

Plasma donepezil and 6ODD concentrations were measured using liquid chromatography tandem mass spectrometry. Sex, the concomitant use of psychotropics, and CYP2D6, CYP3A5, and ABCB1 polymorphisms were analyzed as possible influencers.

RESULTS

The mean plasma concentrations of donepezil and 6ODD were well correlated (R2 = 0.418). The mean plasma concentration ratio of donepezil to 6ODD (metabolic ratio) was significantly lower in intermediate metabolizers of CYP2D6 than in extensive metabolizers. The metabolic ratio in patients receiving psychotropics was significantly lower than in those not receiving psychotropics. Among intermediate metabolizers, patients positive for CYP3A5 *3/*3 showed a significant increase in plasma mean 6ODD concentrations when compared with those who did not express this gene (CYP3A5 *1/*1 or *1/*3).

CONCLUSIONS

Results indicate that the mean plasma concentration ratio of donepezil to 6ODD is associated with CYP2D6 polymorphism and the concomitant use of psychotropics in patients with Alzheimer disease. In intermediate metabolizers, CYP3A5 may play a significant role in the metabolism of donepezil.

Female and male rats readily consume and prefer oxycodone to water in a chronic, continuous access, two-bottle oral voluntary paradigm

The increasing abuse of opioids - such as oxycodone - poses major challenges for health and socioeconomic systems. Human prescription opioid abuse is marked by chronic, voluntary, oral intake and sex differences. To develop interventions, the field would benefit from a preclinical paradigm that similarly provides rodents with chronic, continuous, oral, voluntary and free-choice access to oxycodone. Here we show female and male rats voluntarily ingest and choose oxycodone over water and show both dependence and motivation to take oxycodone during a chronic oral voluntary, two-bottle choice, continuous access paradigm. Adult female and male Long-Evans rats were given unlimited, continuous homecage access to two bottles containing water (Control) or one bottle of water and one bottle of oxycodone dissolved in water (Experimental). Virtually all experimental rats voluntarily drank oxycodone (~10 mg/kg/day) and escalated their intake over 22 weeks. Females self-administered twice as much oxycodone by body weight (leading to higher blood levels of oxycodone) and engaged in more gnawing behavior of wooden blocks relative to males. Precipitated withdrawal revealed high levels of dependence in both sexes. Reflecting motivation to drink oxycodone, ascending concentrations of citric acid suppressed the intake of oxycodone (Experimental) and the intake of water (Control); however, Experimental rats returned to pre-citric acid preference levels whereas Controls rats did not. Pre-screening behaviors of rats on open field exploration predicted oxycodone intake. Thus, rats consumed and preferred oxycodone over time in this chronic two-bottle oral choice paradigm and both sexes displayed many features of human oxycodone abuse.

Erector spinae-plane block as an analgesic alternative in patients undergoing mitral and/or tricuspid valve repair through a right mini-thoracotomy - an observational cohort study

Introduction

One of the main challenges in cardiac surgery is effective postoperative analgesia. Erector spinae-plane block (ESP block) is a novel regional technique, introduced by Forero in 2016 for neuropathic chest pain, then used successfully for mastectomy.

Aim

To establish the efficacy of the ESP block in patients undergoing mitral and/or tricuspid valve repair through a right mini-thoracotomy.

Material and methods

It is a prospective observational cohort study performed in a tertiary health center. In the treatment group, a single-shot ESP block was performed before anesthetic induction. General anesthesia was induced with etomidate, remifentanil, and rocuronium, and continued with sevoflurane and remifentanil. Remifentanil infusion was continued for 2 h post-operatively, then stopped, and the patient’s trachea was extubated. Patient-controlled analgesia was started with oxycodone immediately. Total oxycodone consumption and pain severity on the visual analog scale during the first 24 h were analyzed. In the control group, no regional block was performed. Instead of remifentanil, fentanyl was used. Patients were extubated on the second day. Pain was treated with morphine, administered according to nurses’ discretion. Pain intensity was evaluated on the numerical rating scale.

Results

Nineteen patients were evaluated in the ESP and 25 in the control group. Mechanical ventilation time was shorter in the ESP group (0.6 (0.4–1.1) h) than in the control one (10 (8–17) h, p = 0.00001). Moreover, patients in the ESP group spent fewer days in the intensive care unit (1 (1–1) vs. (2 (2–2), p = 0.0001).

Conclusions

The ESP block seems to be safe and efficient for pain control in patients undergoing right mini-thoracotomy for mitral and/or tricuspid valve repair.

Preclinical and Clinical Pharmacology of Hydrocodone for Chronic Pain: A Mini Review

Hydrocodone is one of the most prescribed oral analgesic drugs and it is one of the most abused drugs in general population. It is a mu-opioid agonist predominantly metabolized to the O-demethylated product hydromorphone and to the N-demethylated product norhydrocodone. The purpose of the study is to summarize the preclinical and clinical characteristics of hydrocodone. Pharmacokinetic aspect (terminal half-life, maximum serum concentration, and time to maximum serum concentration) of hydrocodone and the influence of metabolic genetic polymorphism in analgesic response to hydrocodone are also illustrated and commented. Literature on experimental preclinical pharmacology investigating analgesic activity in laboratory animals is furtherly discussed. Moreover, the authors discuss and comment on the updated data regarding safety profile and effectiveness of hydrocodone in the treatment of chronic pain. A bibliographic research was carried out (from February 01, 2018 to August 28, 2018) independently by two researchers (blinded to the authors and initially on results) in the major scientific databases and research engines of peer-reviewed literature on life sciences and biomedical topics, starting from January 1990 to August 2018. Analysis of results of clinical studies suggests that abuse-deterrent extended-release (ER) hydrocodone formulations can be effective and they are well tolerated in the treatment of chronic low back pain. Weaker is the evidence of the analgesic effectiveness of ER hydrocodone on other chronic pain syndromes and non-cancer non-neuropathic chronic pain. In these conditions, hydrocodone showed to have positive effects in non-controlled open studies and needs to be further studied to assess the real strength of results.

Repeated Morphine Produces Sensitization to Reward and Tolerance to Antiallodynia in Male and Female Rats with Chemotherapy-Induced Neuropathy

Paclitaxel is a cancer chemotherapy drug with adverse effects that include chemotherapy-induced neuropathic pain (CINP) as well as depression of behavior and mood. In the clinical setting, opioids are often used concurrently with or after chemotherapy to treat pain related to the cancer or CINP, but repeated opioid exposure can also increase the risk of opioid abuse. In this study, male and female Sprague-Dawley rats were used to test the hypothesis that repeated 3.2-mg/kg doses of morphine would induce tolerance to its antinociceptive effects in a mechanical sensitivity assay and increased expression of its abuse-related rewarding effects in an assay of intracranial self-stimulation (ICSS). Three weeks after four injections of vehicle or 2.0 mg/kg of paclitaxel, the initial morphine dose-effect curves were determined in both assays. Subsequently, rats were treated with 3.2 mg/kg per day morphine for 6 days. On the final day of testing, morphine dose-effect curves were redetermined in both assays. On initial exposure, morphine produced dose-dependent antiallodynia in the assay of mechanical sensitivity, but it produced little or no rewarding effects in the assay of ICSS. After 6 days of repeated treatment, morphine antiallodynia decreased, and morphine reward increased. Females exhibited greater morphine reward on initial exposure than males, but repeated morphine eliminated this sex difference. These results suggest that repeated morphine may produce tolerance to therapeutically beneficial analgesic effects of morphine but increased sensitivity to abuse-related rewarding effects of morphine in subjects treated with paclitaxel.

Sex differences in prescription opioid use

PURPOSE OF REVIEW

Recent literature focused on prescription opioids has neglected sex differences in use. Here, we evaluated the recent literature (since 2015) examining sex differences in prescription opioid use.

RECENT FINDINGS

Between 2015 and 2016, our review found only eight articles addressing sex differences in prescription opioid use mostly opioid misuse in North America among individuals with chronic pain. Risk factors included depression, pain, and polydrug use. In addition to that review, we had the opportunity to further address sex differences in, and risk factors for, prescription opioid use through a community engagement program, HealthStreet. Among the sample (n = 8525, Mage = 43.7 years, 58.6% women), approximately half reported use of prescription opioids. Women were significantly more likely to report lifetime use (54.9 vs. 42.2%; P < 0.0001) and report cancer compared with men, yet, women with cancer had a significantly reduced risk of using opioids compared with men with cancer (odds ratio: 0.46; 95% confidence interval, 0.36-0.59).

SUMMARY

Only a few recently published studies analyzed sex differences related to prescription opioid use. Findings from the literature and our data suggest women are more likely to use prescription opioids compared with men. There is limited information on sex differences in opioid use risk factors and outcomes and more research in this area is warranted.

Pharmacokinetics of guaifenesin, pseudoephedrine and hydrocodone in a combination oral liquid formulation, administered as single and multiple doses in healthy Chinese volunteers, and comparison with data for individual compounds formulated as Antuss®

1. A new oral liquid formulation combining guaifenesin, pseudoephedrine and hydrocodone is effective in improving the symptoms of common cold. The pharmacokinetic properties of the individual components were evaluated in a randomized, open-label, four-period study in 12 healthy Chinese volunteers following single and multiple doses. The data were compared with data for the individual ingredients in Antuss®. 2. In the single-dose period, exposure levels (AUC and C_max) for guaifenesin, pseudoephedrine and hydrocodone increased directly as the dose of the oral liquid formulation increased from 5 to 15 mL. Only minor amounts of guaifenesin and hydrocodone were excreted in urine (∼0.10% and 4.66%, respectively). Pseudoephedrine was mainly excreted unchanged, with 44.95% of the dose excreted in urine within 24 h. After multiple dosing, there was no obvious accumulation of any drug, as assessed by AUC. When considering C_max, there was a trend toward accumulation of hydrocodone and pseudoephedrine. The pharmacokinetic profiles of guaifenesin and pseudoephedrine in the oral liquid formulation were similar to those in the branded preparation, Antuss®. 3. The newly developed oral liquid formulation combining guaifenesin, pseudoephedrine and hydrocodone was safe and well tolerated and might provide a reliable alternative to the branded formulation for patients with common colds.