Machine learning identifies risk factors associated with long-term opioid use in fibromyalgia patients newly initiated on an opioid.

OBJECTIVES: Fibromyalgia is frequently treated with opioids due to limited therapeutic options. Long-term opioid use is associated with several adverse outcomes. Identifying factors associated with long-term opioid use is the first step in developing targeted interventions. The aim of this study was to evaluate risk factors in fibromyalgia patients newly initiated on opioids using machine learning. METHODS: A retrospective cohort study was conducted using a nationally representative primary care dataset from the UK, from the Clinical Research Practice Datalink. Fibromyalgia patients without prior cancer who were new opioid users were included. Logistic regression, a random forest model and Boruta feature selection were used to identify risk factors related to long-term opioid use. Adjusted ORs (aORs) and feature importance scores were calculated to gauge the strength of these associations. RESULTS: In this study, 28 552 fibromyalgia patients initiating opioids were identified of which 7369 patients (26%) had long-term opioid use. High initial opioid dose (aOR: 31.96, mean decrease accuracy (MDA) 135), history of self-harm (aOR: 2.01, MDA 44), obesity (aOR: 2.43, MDA 36), high deprivation (aOR: 2.00, MDA 31) and substance use disorder (aOR: 2.08, MDA 25) were the factors most strongly associated with long-term use. CONCLUSIONS: High dose of initial opioid prescription, a history of self-harm, obesity, high deprivation, substance use disorder and age were associated with long-term opioid use. This study underscores the importance of recognising these individual risk factors in fibromyalgia patients to better navigate the complexities of opioid use and facilitate patient-centred care.

Low-Dose Alfentanil Inhibits Sufentanil-Induced Cough During Anesthesia Induction: A Prospective, Randomized, Double-Blind Study.

Background: Cough is one of the most common complications following intravenous administration of sufentanil during anesthesia induction. The study aimed to investigate the protective effect of alfentanil, afentanyl derivative with short onset time and short duration, in reducing sufentanil-induced cough. Patients and methods: Eighty patients that scheduled for thyroid surgery under general anesthesia were randomly divided into the alfentanil group and normal saline group, with 40 cases per group. Patients in the alfentanil group received intravenous administration of 2 µg/kg alfentanil prior to sufentanil injection during general anesthesia induction, while the same dose of normal saline was administered in the normal saline group. The outcomes measures included the incidence and severity of cough and common side effects of opioids following the administration of sufentanil during the induction of general anesthesia, intraoperative hemodynamics parameters and major adverse events during anesthesia recovery period. Results: The incidence of cough within one minute after the injection of sufentanil during anesthesia induction was 40% in the normal saline group, and the pretreatment of alfentanil significantly reduced the incidence of sufentanil-induced cough to 5% (p < 0.05). Correspondingly, the patients in the alfentanil group had decreased severity of sufentanil-induced cough compared with the normal saline group (p < 0.05). No significant differences in the incidences of common side effects of opioids (dizziness, nausea and vomiting, chest tightness and respiratory depression) within one minute after sufentanil injection were found (p > 0.05). Furthermore, there were no significant differences between the two groups in intraoperative hemodynamic parameters, extubation time, or the incidences of emergence agitation, respiratory depression, delayed recovery from anesthesia and postoperative nausea and vomiting during Postanesthesia Care Unit stay (p > 0.05). Conclusion: Pretreatment with low-dose alfentanil (2 µg/kg) effectively and safely reduced both the incidence and severity of sufentanil-induced cough during anesthesia induction. Clinical Trial Registration Number: Chinese Clinical Trial Registry (identifier: ChiCTR2300069286).

Balanced opioid-free anesthesia with lidocaine and esketamine versus balanced anesthesia with sufentanil for gynecological endoscopic surgery: a randomized controlled trial.

In this randomized controlled trial, 74 patients scheduled for gynecological laparoscopic surgery (American Society of Anesthesiologists grade I/II) were enrolled and randomly divided into two study groups: (i) Group C (control), received sufentanil (0.3 µg/kg) and saline, followed by sufentanil (0.1 µg/kg∙h) and saline; and (ii) Group F (OFA), received esketamine (0.15 mg/kg) and lidocaine (2 mg/kg), followed by esketamine (0.1 mg/kg∙h) and lidocaine (1.5 mg/kg∙h). The primary outcome was the 48-h time-weighted average (TWA) of postoperative pain scores. Secondary outcomes included time to extubation, adverse effects, and postoperative sedation score, pain scores at different time points, analgesic consumption at 48 h, and gastrointestinal functional recovery. The 48-h TWAs of pain scores were 1.32 (0.78) (95% CI 1.06-1.58) and 1.09 (0.70) (95% CI 0.87-1.33) for Groups F and C, respectively. The estimated difference between Groups F and C was - 0.23 (95% CI - 0.58 - 0.12; P = 0.195). No differences were found in any of the secondary outcomes and no severe adverse effects were observed in either group. Balanced OFA with lidocaine and esketamine achieved similar effects to balanced anesthesia with sufentanil in patients undergoing elective gynecological laparoscopic surgery, without severe adverse effects.Clinical Trial Registration: ChiCTR2300067951, www.chictr.org.cn 01 February, 2023.

Prevention of persistent pain with lidocaine infusions in breast cancer surgery (PLAN): study protocol for a multicenter randomized controlled trial.

BACKGROUND: Persistent pain is a common yet debilitating complication after breast cancer surgery. Given the pervasive effects of this pain disorder on the patient and healthcare system, post-mastectomy pain syndrome (PMPS) is becoming a larger population health problem, especially as the prognosis and survivorship of breast cancer increases. Interventions that prevent persistent pain after breast surgery are needed to improve the quality of life of breast cancer survivors. An intraoperative intravenous lidocaine infusion has emerged as a potential intervention to decrease the incidence of PMPS. We aim to determine the definitive effects of this intervention in patients undergoing breast cancer surgery. METHODS: PLAN will be a multicenter, parallel-group, blinded, 1:1 randomized, placebo-controlled trial of 1,602 patients undergoing breast cancer surgery. Adult patients scheduled for a lumpectomy or mastectomy will be randomized to receive an intravenous 2% lidocaine bolus of 1.5 mg/kg with induction of anesthesia, followed by a 2.0 mg/kg/h infusion until the end of surgery, or placebo solution (normal saline) at the same volume. The primary outcome will be the incidence of persistent pain at 3 months. Secondary outcomes include the incidence of pain and opioid consumption at 1 h, 1-3 days, and 12 months after surgery, as well as emotional, physical, and functional parameters, and cost-effectiveness. DISCUSSION: This trial aims to provide definitive evidence on an intervention that could potentially prevent persistent pain after breast cancer surgery. If this trial is successful, lidocaine infusion would be integrated as standard of care in breast cancer management. This inexpensive, widely available, and easily administered intervention has the potential to reduce pain and suffering in an already afflicted patient population, decrease the substantial costs of chronic pain management, potentially decrease opioid use, and improve the quality of life in patients. TRIAL REGISTRATION: This trial has been registered on clinicaltrials.gov (NCT04874038, Dr. James Khan. Date of registration: May 5, 2021).

[Pharmacological pain management in cancer patients]. / Medikamentöse Schmerztherapie bei Patienten mit Tumorerkrankungen.

Pharmacological pain therapy in cancer patients is based on guideline recommendations, which, however, do not fully coincide in all aspects due to varying weighting of evidence. The present article discusses current issues including the decreasing significance of the World Health Organization (WHO) analgesic ladder, with its distinction between step 2 and 3 being increasingly questioned. Risks of nonopioid analgesics such as paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs), particularly in older populations, are discussed. Paracetamol may potentially reduce the effectiveness of immunotherapies. Aspects of administering analgesics via a feeding tube are considered. Recommendations for the treatment of episodic pain, transitioning between different opioids, and some relevant interactions are also discussed.

Clinical prediction of opioid use disorder in chronic pain patients: a cohort-retrospective study with a pharmacogenetic approach.

BACKGROUND: Opioids are widely used in chronic non-cancer pain (CNCP) management. However, they remain controversial due to serious risk of causing opioid use disorder (OUD). Our main aim was to develop a predictive model for future clinical translation that include pharmacogenetic markers. METHODS: An observational study was conducted in 806 pre-screened Spanish CNCP patients, under long-term use of opioids, to compare cases (with OUD, N.=137) with controls (without OUD, N.=669). Mu-opioid receptor 1 (OPRM1, A118G, rs1799971) and catechol-O-methyltransferase (COMT, G472A, rs4680) genetic variants plus cytochrome P450 2D6 (CYP2D6) liver enzyme phenotypes were analyzed. Socio-demographic, clinical and pharmacological outcomes were also registered. A logistic regression model was performed. The model performance and diagnostic accuracy were calculated. RESULTS: OPRM1-AA genotype and CYP2D6 poor and ultrarapid metabolizers together with three other potential predictors: 1) age; 2) work disability; 3) oral morphine equivalent daily dose (MEDD), were selected with a satisfactory diagnostic accuracy (sensitivity: 0.82 and specificity: 0.85), goodness of fit (P=0.87) and discrimination (0.89). Cases were ten-year younger with lower incomes, more sleep disturbances, benzodiazepines use, and history of substance use disorder in front of controls. CONCLUSIONS: Functional polymorphisms related to OPRM1 variant and CYP2D6 phenotypes may predict a higher OUD risk. Established risk factors such as young age, elevated MEDD and lower incomes were identified. A predictive model is expected to be implemented in clinical setting among CNCP patients under long-term opioids use.

Opioid use disorder in pediatric populations: considerations for perioperative pain management and precision opioid analgesia.

INTRODUCTION: Opioids are commonly used for perioperative analgesia, yet children still suffer high rates of severe post-surgical pain and opioid-related adverse effects. Persistent and severe acute surgical pain greatly increases the child's chances of chronic surgical pain, long-term opioid use, and opioid use disorder. AREAS COVERED: Enhanced recovery after surgery (ERAS) protocols are often inadequate in treating a child's severe surgical pain. Research suggests that 'older' and longer-acting opioids such as methadone are providing better methods to treat acute post-surgical pain. Studies indicate that lower repetitive methadone doses can decrease the incidence of chronic persistent surgical pain (CPSP). Ongoing research explores genetic components influencing severe surgical pain, inadequate opioid analgesia, and opioid use disorder. This new genetic research coupled with better utilization of opioids in the perioperative setting provides hope in personalizing surgical pain management, reducing pain, opioid use, adverse effects, and helping the fight against the opioid pandemic. EXPERT OPINION: The opioid and analgesic pharmacogenomics approach can proactively 'tailor' a perioperative analgesic plan to each patient based on underlying polygenic risks. This transition from population-based knowledge of pain medicine to individual patient knowledge can transform acute pain medicine and greatly reduce the opioid epidemic's socioeconomic, personal, and psychological strains globally.

Opioid utilization after orthopaedic trauma hospitalization among Medicaid-insured adults.

Opioids are vital to pain management and sedation after trauma-related hospitalization. However, there are many confounding clinical, social, and environmental factors that exacerbate pain, post-injury care needs, and receipt of opioid prescriptions following orthopaedic trauma. This retrospective study sought to characterize differences in opioid prescribing and dosing in a national Medicaid eligible sample from 2010-2018. The study population included adults, discharged after orthopaedic trauma hospitalization, and receiving an opioid prescription within 30 days of discharge. Patients were identified using the International Classification of Diseases (ICD-9; ICD-10) codes for inpatient diagnosis and procedure. Filled opioid prescriptions were identified from National Drug Codes and converted to morphine milligram equivalents (MME). Opioid receipt and dosage (e.g., morphine milligram equivalents [MME]) were examined as the main outcomes using regressions and analyzed by year, sex, race/ethnicity, residence rurality-urbanicity, and geographic region. The study population consisted of 86,091 injured Medicaid-enrolled adults; 35.3% received an opioid prescription within 30 days of discharge. Male patients (OR = 1.12, 95% CI: 1.07-1.18) and those between 31-50 years of age (OR = 1.15, 95% CI: 1.08-1.22) were found to have increased odds ratio of receiving an opioid within 30 days of discharge, compared to female and younger patients, respectively. Patients with disabilities (OR = 0.75, 95% CI: 0.71-0.80), prolonged hospitalizations, and both Black (OR = 0.87, 95% CI: 0.83-0.92) and Hispanic patients (OR = 0.72, 95% CI: 0.66-0.77), relative to white patients, had lower odds ratio of receiving an opioid prescription following trauma. Additionally, Black and Hispanic patients received lower prescription doses compared to white patients. Individuals hospitalized in the Southeastern United States and those between the ages of 51-65 age group were found to be prescribed lower average daily MME. There were significant variations in opioid prescribing practices by race, sex, and region. National guidelines for use of opioids and other pain management interventions in adults after trauma hospitalization may help limit practice variation and reduce implicit bias and potential harms in outpatient opioid usage.

Advances in animal models of prenatal opioid exposure.

Neonatal opioid withdrawal syndrome (NOWS) is a growing public health concern. The complexity of in utero opioid exposure in clinical studies makes it difficult to investigate underlying mechanisms that could ultimately inform early diagnosis and treatments. Clinical studies are unable to dissociate the influence of maternal polypharmacy or the environment from direct effects of in utero opioid exposure, highlighting the need for effective animal models. Early animal models of prenatal opioid exposure primarily used the prototypical opioid, morphine, and opioid exposure that was often limited to a narrow period during gestation. In recent years, the number of preclinical studies has grown rapidly. Newer models utilize both prescription and nonprescription opioids and vary the onset and duration of opioid exposure. In this review, we summarize novel prenatal opioid exposure models developed in recent years and attempt to reconcile results between studies while critically identifying gaps within the current literature.

Perioperative pain optimization in the age of the opioid epidemic.

PURPOSE OF REVIEW: The opioid epidemic remains a constant and increasing threat to our society with overdoses and overdose deaths rising significantly during the COVID-19 pandemic. Growing evidence suggests a link between perioperative opioid use, postoperative opioid prescribing, and the development of opioid use disorder (OUD). As a result, strategies to better optimize pain management during the perioperative period are urgently needed. The purpose of this review is to summarize the most recent multimodal analgesia (MMA) recommendations, summarize evidence for efficacy surrounding the increased utilization of Enhanced Recovery After Surgery (ERAS) protocols, and discuss the implications for rising use of buprenorphine for OUD patients who present for surgery. In addition, this review will explore opportunities to expand our treatment of complex patients via transitional pain services. RECENT FINDINGS: There is ample evidence to support the benefits of MMA. However, optimal drug combinations remain understudied, presenting a target area for future research. ERAS protocols provide a more systematic and targeted approach for implementing MMA. ERAS protocols also allow for a more comprehensive approach to perioperative pain management by necessitating the involvement of surgical specialists. Increasingly, OUD patients taking buprenorphine are presenting for surgery. Recent guidance from a multisociety OUD working group recommends that buprenorphine not be routinely discontinued or tapered perioperatively. Lastly, there is emerging evidence to justify the use of transitional pain services for more comprehensive treatment of complex patients, like those with chronic pain, preoperative opioid tolerance, or substance use disorder. SUMMARY: Perioperative physicians must be aware of the impact of the opioid epidemic and explore methods like MMA techniques, ERAS protocols, and transitional pain services to improve the perioperative pain experience and decrease the risks of opioid-related harm.

Receipt of prescription opioid medication is associated with increased mortality in an Israeli population.

BACKGROUND: Despite Israel's increased use of prescription opioids, reported deaths resulting or associated with opioids have decreased, in fact dramatically, since 2005. This contrast is unique and difficult to explain. We sought to examine whether higher prescribed opioid dosages among adults without oncologic diagnoses were associated with higher all-cause mortality rates. METHODS: A historical cohort study in Clalit Health Services, using a data repository including all adult patients prescribed opiates between 2010 and 2020, excluding patients with oncologic diagnoses. Patients were classified into three groups according to opioid use: below 50 Morphine milligram equivalents (MME) per day, 50 to 90 MME per day, and above 90 MME per day. Sex, Charlson comorbidity score, age and socioeconomic status were recorded. Mortality rates were compared between the dosage groups and compared to age-standardized mortality rates in the general population. RESULTS: On multivariate analysis, patients receiving 90 or more MME per day were 2.37 (95%CI 2.1 to 2.68) more likely to have died compared to patients receiving below 50 MME per day. The respective hazard ratio among patients receiving between 50 and 90 MME per day was 2.23 (2.01 to 2.46). Among patients aged 18 to 50, standardized mortality ratios (SMRs) compared to the general population ranged between 5.4 to 8.6 among women, receiving between 50 and 90 MME per day, and between 8.07 and 10.7 among women receiving 90 or more MME per day. The respective SMRs among men were 1.2 to 3.8 and 2.7 to 5.4. CONCLUSION: Increased opioid use is independently associated with increased all-cause mortality among non-oncological patients. This result is most notable among young adults with little or no known comorbidities. These findings are consistent with results in other countries and seem more credible than previous Israeli reports. Healthcare regulators and providers should, therefore, act to curtail the increasing opioid prescriptions and devise and enhance controls in the healthcare system, which, until 2020, had very limited mechanisms in place.

Development of Opioid Use Disorder After Breast Reconstruction: Effects of Nicotine Exposure.

INTRODUCTION: After undergoing breast reconstructive surgery, patients are typically prescribed opioids. Smoking tobacco increases rate of opioid metabolism and is associated with development of opioid use disorder (OUD). The aim of this study was to determine whether patients who smoke have an increased risk of OUD after breast reconstructive surgery. Given that OUD is a known risk factor for injection drug use and intravenous drug use increases risk of acquiring blood-borne diseases including human immunodeficiency virus (HIV) and hepatitis, the secondary aim was to determine if these patients are also at increased risk of acquiring these communicable diseases associated with OUD. METHODS: A retrospective analysis was conducted using TriNetX, a multi-institutional deidentified database. Individuals included underwent a breast reconstructive surgery and received postoperative opioid treatment. The exposed group included patients who smoke. The control group did not smoke. Risk of developing OUD, hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV from 12 to 36 months after surgery was compared between groups. Patients with preexisting OUD or associated diseases were excluded. Cohorts were matched to control for confounding factors including age, sex, race, mental health history, and concomitant substance use. RESULTS: There were 8648 patients included in the analysis. After matching, 4324 patients comprised the exposure group, and 4324 patients remained in the control group. Preoperative smoking was significantly associated with increased risk of OUD at 12, 24, and 36 months after breast reconstruction (36 months: odds ratio [OR], 2.722; confidence interval [CI], 2.268-6.375). Smoking was also associated with increased risk of HIV and HCV at all time points after surgery (36 months HIV: OR, 2.614; CI, 1.977-3.458; 36 months HCV: OR, 3.718; CI, 2.268-6.375) and increased risk of HBV beginning at 24 months after surgery (36 months HBV: OR, 2.722; CI, 1.502-4.935). CONCLUSIONS: Individuals who smoke have an increased risk of developing OUD, HIV, HCV, and HBV after breast reconstructive surgery. This risk persists for at least 3 years after surgery. Additional research and clinical interventions focusing on early identification of OUD, prevention efforts, and harm reduction strategies for patients who smoke or have nicotine dependence undergoing breast reconstruction are warranted.

The influence of COMT and ABCB1 gene polymorphisms on sufentanil analgesic effect for postoperative pain in children with fracture.

The aim of this observational study was to investigate the effects of catechol-O-methyltransferase (COMT) and ATP-binding cassette transporter B1 (ABCB1) gene polymorphisms on the postoperative analgesic effect of sufentanil in Chinese Han pediatric patients with fractures. A total of 185 pediatric patients who underwent fracture surgery were included. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the polymorphisms of COMT and ABCB1 genes. Sufentanil was used for postoperative analgesia. The pain level of the patients was evaluated using the face, legs, activity, cry, and consolability scale before surgery, during awakening, at 2, 6, 12, and 24 hours after surgery. The postoperative Ramsay sedation score, sufentanil consumption, and incidence of adverse reactions were also recorded. Pediatric patients with different genotypes of ABCB1 and COMT showed no statistically significant differences in general data such as age, gender, weight, height, surgical duration, and American Society of Anesthesiologists classification (P > .05). There were no statistically significant differences in sedation scores after surgery between different genotypes of ABCB1 and COMT (P > .05). Among patients with CC genotype in ABCB1, the pain scores and total consumption of sufentanil at awakening, 2 and 6 hours after surgery were higher compared to TT and CT genotypes (P < .05), while there were no statistically significant differences between TT and CT genotypes (P > .05). Among patients with AA genotype in COMT, the pain scores and total consumption of sufentanil at awakening, 2, 6, 12, and 24 hours after surgery were higher compared to AG and GG genotypes (P < .05), while there were no statistically significant differences between AG and GG genotypes (P > .05). There were no statistically significant differences in adverse reactions between different genotypes of ABCB1 and COMT (P > .05). The polymorphisms of COMT gene rs4680 and ABCB1 gene rs1045642 are associated with the analgesic effect and consumption of sufentanil in pediatric patients after fracture surgery.

Opioid-induced respiratory depression suspected of drug interaction in a prostate cancer patient: a case report.

BACKGROUND: Many of the drugs used for the treatment and alleviation of symptoms in cancer patients are known to inhibit or induce cytochrome P450 (CYP). Therefore, it is important to pay attention to the drug interactions of opioid analgesics that are metabolized by CYPs, because for example when using oxycodone metabolized by CYP3A4, it is possible that the effect will be attenuated or enhanced by the concomitant use of drugs that induce or inhibit CYP3A4. Aprepitant, an antiemetic drug used in many patients receiving anticancer drugs, is known as a moderate competitive inhibitor of CYP3A4. We experienced a case of respiratory depression caused by opioids, which was suspected to be caused by a drug interaction with antiemetics especially aprepitant. CASE DESCRIPTION: The patient was a 72-year-old man. He had been treated with continuous oxycodone infusion for perianal pain associated with the rectal invasion of prostate cancer. No comorbidities other than renal dysfunction were observed. Oxycodone treatment was started at 48 mg/day, and was increased to 108 mg/day, and then the pain decreased. Once the pain was controlled, chemotherapy was planned. Antiemetics (dexamethasone, palonosetron, and aprepitant) were administered before anticancer drug administration. Approximately 3 hours after antiemetics administration and before the administration of the anticancer drugs, a ward nurse noticed that oversedation and respiratory depression had occurred. When the patient was called, he immediately woke up and was able to talk normally, so the anticancer drugs were administered as scheduled. About 2 hours after the nurse noticed oversedation, the attending physician reduced the dose of oxycodone infusion to 48 mg/day. After that, his drowsiness persisted, but his respiratory condition improved. Despite reducing the dose of oxycodone to less than half, the pain remained stable at numeric rating scale (NRS) 0-1, without the use of a rescue dose. The patient was discharged from the hospital 36 days after the administration of anticancer drugs, without any problems. CONCLUSIONS: The cause of respiratory depression in this case was thought to be a combination of factors, including drug interactions between oxycodone and antiemetics, and oxycodone accumulation due to renal dysfunction.

Dysphagia as a Missing Link Between Post-surgical- and Opioid-Related Pneumonia.

PURPOSE: Postoperative pneumonia remains a common complication of surgery, despite increased attention. The purpose of our study was to determine the effects of routine surgery and post-surgical opioid administration on airway protection risk. METHODS: Eight healthy adult cats were evaluated to determine changes in airway protection status and for evidence of dysphagia in two experiments. (1) In four female cats, airway protection status was tracked following routine abdominal surgery (spay surgery) plus low-dose opioid administration (buprenorphine 0.015 mg/kg, IM, q8-12 h; n = 5). (2) Using a cross-over design, four naive cats (2 male, 2 female) were treated with moderate-dose (0.02 mg/kg) or high-dose (0.04 mg/kg) buprenorphine (IM, q8-12 h; n = 5). RESULTS: Airway protection was significantly affected in both experiments, but the most severe deficits occurred post-surgically as 75% of the animals exhibited silent aspiration. CONCLUSION: Oropharyngeal swallow is impaired by the partial mu-opioid receptor agonist buprenorphine, most remarkably in the postoperative setting. These findings have implications for the prevention and management of aspiration pneumonia in vulnerable populations.

Peptide-derived ligands for the discovery of safer opioid analgesics.

Drugs targeting the µ-opioid receptor (MOR) remain the most efficacious analgesics for the treatment of pain, but activation of MOR with current opioid analgesics also produces harmful side effects, notably physical dependence, addiction, and respiratory depression. Opioid peptides have been accepted as promising candidates for the development of safer and more efficacious analgesics. To develop peptide-based opioid analgesics, strategies such as modification of endogenous opioid peptides, development of multifunctional opioid peptides, G protein-biased opioid peptides, and peripherally restricted opioid peptides have been reported. This review seeks to provide an overview of the opioid peptides that produce potent antinociception with much reduced side effects in animal models and highlight the potential advantages of peptides as safer opioid analgesics.

Duloxetine reduces opioid consumption and pain after total hip or knee arthroplasty: a meta-analysis of randomized controlled trials.

PURPOSE: There is no consensus in the current literature on the analgesic role of duloxetine after total hip arthroplasty (THA) or total knee arthroplasty (TKA). Thus, we designed this meta-analysis to reveal the analgesic effectiveness and safety of duloxetine in TKA or THA. METHODS: As of October 2022, two authors (L.C. and W.Q.J.) independently searched five main databases (EMBASE, Web of Science, PubMed, Cochrane Library, and Google Scholar) to find relevant studies. Duloxetine vs. placebo in randomized controlled trials (RCTs) for THA or TKA were included. We set perioperative total opioid consumption as the primary outcome. Secondary outcomes included resting or dynamic pain scores over time, gastrointestinal adverse events, neurological adverse events, and other adverse reactions. RESULTS: Eight RCTs with 695 patients were incorporated in our study. This meta-analysis showed high evidence that duloxetine was effective in reducing perioperative opioid consumption (Standard mean difference [SMD] = - 0.50, 95% confidence intervals [CI]: -0.70 to - 0.31, P < 0.00001) and low to moderate evidence that duloxetine could reduce pain within three weeks after surgery. Low to high evidence showed no differences between the two groups for most adverse events. Substantial evidence suggests that duloxetine can reduce nausea and vomiting after surgery (Risk ratio [RR] = 0.69, 95% CI: 0.50 to 0.95, P = 0.02, I2 = 4%). However, moderate evidence suggested that duloxetine might be associated with increased postoperative drowsiness (RR = 1.83, 95% CI: 1.08 to 3.09, P = 0.02, I2 = 0%). CONCLUSION: Duloxetine reduced overall opioid consumption in the perioperative period and relieved pain within three weeks after surgery without increasing the risk of adverse drug events. Duloxetine can be part of a multimodal management regimen in patients with THA and TKA.

Opioid use in cancer patients compared with noncancer pain patients in a veteran population.

BACKGROUND: Opioid safety initiatives may secondarily impact opioid prescribing and pain outcomes for cancer care. METHODS: We reviewed electronic health record data at a tertiary Veterans Affairs system (VA Palo Alto) for all patients from 2015 to 2021. We collected outpatient Schedule II opioid prescriptions data and calculated morphine milligram equivalents (MMEs) using Centers for Disease Control and Prevention conversion formulas. To determine the clinical impact of changes in opioid prescription, we used the highest level of pain reported by each patient on the 0-to-10 Numeric Rating Scale in each year, categorized into mild (0-3), moderate (4-6), and severe (7 and above). RESULTS: Among 89 569 patients, 9073 had a cancer diagnosis. Cancer patients were almost twice as likely to have an opioid prescription compared with noncancer patients (69.0% vs 36.7%, respectively). The proportion of patients who received an opioid prescription decreased from 27.1% to 18.1% (trend P < .01) in cancer patients and from 17.0% to 10.2% in noncancer patients (trend P < .01). Cancer and noncancer patients had similar declines of MMEs per year between 2015 and 2019, but the decline was more rapid for cancer patients (1462.5 to 946.4, 35.3%) compared with noncancer patients (1315.6 to 927.7, 29.5%) from 2019 to 2021. During the study period, the proportion of noncancer patients who experienced severe pain was almost unchanged, whereas it increased among cancer patients, reaching a significantly higher rate than among noncancer patients in 2021 (31.9% vs 27.4%, P < .01). CONCLUSIONS: Our findings suggest potential unintended consequences for cancer care because of efforts to manage opioid-related risks.

Efficacy and safety of naldemedine for opioid-induced constipation in older patients with cancer: a retrospective study.

BACKGROUND: Opioids are pain relievers that are often associated with opioid-induced constipation (OIC) that worsens with age. We performed a multicenter, retrospective analysis on the efficacy and safety of naldemedine, an opioid receptor antagonist, in treating OIC in patients with cancer (age >75 years). METHODS: The electronic medical records of cancer patients who received naldemedine at 10 Japanese institutions between 7 June 2017 and August 31, 2019, were retrieved. Patients aged ≥75 years who were treated with naldemedine for the first time and hospitalized for at least 7 days before and after initiating naldemedine therapy were included in this analysis. RESULTS: Sixty patients were observed for at least 7 days before and after starting naldemedine. The response rate was 68.3%, and the frequency of bowel movements increased significantly after naldemedine administration in the overall population ( P  < 0.0001) and among those who defecated <3 times/week before naldemedine administration ( P  < 0.0001). Diarrhea was the most frequent adverse event in all grades, observed in 45% of patients, of which 92.6% were Grade 1 or 2. Grade 4 or higher adverse events, including death, were not observed. CONCLUSION: Naldemedine exhibits significant efficacy and safety in OIC treatment in older patients with cancer.

Pharmacological prevention and treatment of opioid-induced constipation in cancer patients: A systematic review and meta-analysis.

BACKGROUND: Cancer-related pain often requires opioid treatment with opioid-induced constipation (OIC) as its most frequent gastrointestinal side-effect. Both for prevention and treatment of OIC osmotic (e.g. polyethylene glycol) and stimulant (e.g. bisacodyl) laxatives are widely used. Newer drugs such as the peripherally acting µ-opioid receptor antagonists (PAMORAs) and naloxone in a fixed combination with oxycodone have become available for the management of OIC. This systematic review and meta-analysis aims to give an overview of the scientific evidence on pharmacological strategies for the prevention and treatment of OIC in cancer patients. METHODS: A systematic search in PubMed, Embase, Web of Science and the Cochrane Library was completed from inception up to 22 October 2022. Randomized and non-randomized studies were systematically selected. Bowel function and adverse drug events were assessed. RESULTS: Twenty trials (prevention: five RCTs and three cohort studies; treatment: ten RCTs and two comparative cohort studies) were included in the review. Regarding the prevention of OIC, three RCTs compared laxatives with other laxatives, finding no clear differences in effectivity of the laxatives used. One cohort study showed a significant benefit of magnesium oxide compared with no laxative. One RCT found a significant benefit for the PAMORA naldemedine compared with magnesium oxide. Preventive use of oxycodone/naloxone did not show a significant difference in two out of three other studies compared to oxycodone or fentanyl. A meta-analysis was not possible. Regarding the treatment of OIC, two RCTs compared laxatives, of which one RCT found that polyethylene glycol was significantly more effective than sennosides. Seven studies compared an opioid antagonist (naloxone, methylnaltrexone or naldemedine) with placebo and three studies compared different dosages of opioid antagonists. These studies with opioid antagonists were used for the meta-analysis. Oxycodone/naloxone showed a significant improvement in Bowel Function Index compared to oxycodone with laxatives (MD -13.68; 95 % CI -18.38 to -8.98; I2 = 58 %). Adverse drug event rates were similar amongst both groups, except for nausea in favour of oxycodone/naloxone (RR 0.51; 95 % CI 0.31-0.83; I2 = 0 %). Naldemedine (NAL) and methylnaltrexone (MNTX) demonstrated significantly higher response rates compared to placebo (NAL: RR 2.07, 95 % CI 1.64-2.61, I2 = 0 %; MNTX: RR 3.83, 95 % CI 2.81-5.22, I2 = 0 %). With regard to adverse events, abdominal pain was more present in treatment with methylnaltrexone and diarrhea was significantly more present in treatment with naldemedine. Different dosages of methylnaltrexone were not significantly different with regard to both efficacy and adverse drug event rates. CONCLUSIONS: Magnesium oxide and naldemedine are most likely effective for prevention of OIC in cancer patients. Naloxone in a fixed combination with oxycodone, naldemedine and methylnaltrexone effectively treat OIC in cancer patients with acceptable adverse events. However, their effect has not been compared to standard (osmotic and stimulant) laxatives. More studies comparing standard laxatives with each other and with opioid antagonists are necessary before recommendations for clinical practice can be made.