Buprenorphine: a treatment and cause of opioid-induced respiratory depression

Research progress on the impact of opioids on the tumor immune microenvironment (Review)

Opioids have been extensively used in cancer pain management because they can significantly improve the quality of life of patients with advanced cancer. However, recent evidence suggests that opioids can also modulate the tumor immune microenvironment by interacting with opioid receptors on immune cells, potentially regulating tumor progression and efficacy of cancer treatments. Notably, morphine can exhibit a dose-dependent effect on tumor immunity in pancreatic cancer and renal cell models, with lower doses potentially promoting tumor migration and invasion of pancreatic cancer cells, whereas higher doses shows the effect of inhibiting migration and invasion through distinct molecular pathways. The present review therefore comprehensively explored the mechanisms by which opioids can regulate the tumor immune microenvironment, focusing on their effects on immune cells, oxidative stress and angiogenesis. It also examined the interactions between opioids and other analgesics, along with their potential impact on immune modulation. All relevant articles and materials were retrieved from PubMed using the key words 'opioids', 'immune system', 'T cells', 'monocytes', 'macrophages', 'lymphocytes', 'natural killer cell', 'immunotherapy', 'immune cell function' and 'dose dependent effect'. The immunosuppressive effects of opioids, particularly through the µ-opioid receptor, can suppress the activity of natural killer cells, impair antigen presentation and promote the function of regulatory T cells (Tregs). These effects may contribute to tumor progression and metastasis. The severity of these immunosuppressive effects appears to be dose-dependent and can vary among different tumor types. There is evidence to suggest that tumors with higher immune responsiveness will experience more pronounced suppression, including the reduction of tumor angiogenesis, resulting in a decrease in tumor volume and decrease in tumor metastases. Furthermore, the combination of opioids with other analgesics, such as non-steroidal anti-inflammatory drugs, has the potential to exacerbate immunosuppression, which can in turn increase the risk of infections. Therefore, although opioids are essential for pain management in patients with cancer, their potential to modulate the immune microenvironment and promote tumor progression requires careful consideration. Clinicians should evaluate the advantages and disadvantages of opioids, especially regarding emerging immunotherapies, to minimize their potential negative effects on the outcomes of cancer treatments. Future studies are recommended to prioritize the development of strategies that optimize pain management whilst preserving immune function, such as receptor-specific opioid formulations or adjunctive therapies targeting immunosuppressive pathways.

Dezocine modulates the reinstatement of conditioned place preference in morphine-dependent rats via the dopamine reward circuitry

Introduction

Opioid addiction is a significant public health issue, with existing treatments such as buprenorphine and methadone exhibiting limitations, including side effects and insufficient prevention of relapse. Novel therapeutic strategies are needed to address these challenges. This study investigates the potential of dezocine in reducing addiction-related behaviors and preventing relapse.

Methods

A morphine-induced conditioned place preference (CPP) model was established in rats to evaluate the effect of dezocine on addiction-related behaviors. Behavioral assessments were conducted to measure withdrawal symptoms and CPP reinstatement. To explore the underlying mechanism, Western blot (WB) and immunofluorescence (IF) were used to quantify the expression of phosphorylated DARPP32 (p-DARPP32) and DOPA decarboxylase (DDC) in reward-related brain regions, including the nucleus accumbens (NAc), ventral tegmental area (VTA), hippocampus (HP), and prefrontal cortex (PFC).

Results

Dezocine significantly reduced withdrawal symptoms and prevented CPP reinstatement, indicating its potential to alleviate addiction behaviors. Western blotting and immunofluorescence analysis revealed that dezocine increased p-DARPP32 expression in the NAc, VTA, HP, and PFC, without altering DDC levels.

Discussion

These findings suggest that dezocine may exert its therapeutic effects by inhibiting kappa opioid receptor activation and enhancing dopamine signaling in reward-related brain circuitry. The increase in p-DARPP32 expression in key brain regions supports this mechanism, providing insights into the potential clinical application of dezocine for managing opioid addiction. Dezocine represents a promising candidate for opioid addiction treatment, with the ability to control withdrawal symptoms and prevent relapse.

Comparative Efficacy of Esketamine vs Sufentanil with Propofol for Sedation in EUS: A Randomized, Controlled Study

Purpose

This randomized, controlled trial aimed to assess the sedative effects of esketamine and sufentanil combined with propofol during EUS.

Patients and Methods

Three hundred and forty patients undergone EUS were randomly divided into two groups to receive esketamine 0.25 mg/kg combined with propofol (esketamine group) or sufentanil 0.1 μg/kg combined with propofol (sufentanil group). The primary outcome measure was respiratory depression incidence. The secondary outcomes included the incidence of body movements, propofol dosage, lowest SPO2 during the operation, and management of airway obstruction. In addition, other procedures and anesthesia-related outcomes, and postoperative complications were recorded.

Results

A total of 340 patients underwent randomization. Of these, 172 were assigned to the esketamine group and 168 were assigned to the sufentanil group. 1 patient in the esketamine group was lost in the follow-up. During the EUS, 9 patients (5.3%) in the esketamine group and 26 (15.5%) in the sufentanil group developed respiratory depression; this difference was statistically significant (P = 0.002). Regarding secondary outcomes, the incidence of body movements, induction dosage, supplemental times, and total dosage of propofol were much higher in the sufentanil group than in the esketamine group (P < 0.05). In addition, the lowest SPO2 during the operation, occurrence rate of airway intervention, and management of airway obstruction were significantly different (P < 0.05). Compared to the sufentanil group, the induction time of sedation in the esketamine group was shorter, and the hemodynamics were more stable (P < 0.05). In addition, there were significant differences in the PACU incidence rates of nausea or vomiting between the two groups (P < 0.05), whereas the following day's complications showed no statistical difference.

Conclusion

Esketamine combined with propofol for sedation during EUS can decrease respiratory depression, reduce the dosage of propofol and PONV, and provide a more stable hemodynamic state. Consequently, esketamine could be considered as a potential alternative to sufentanil for sedation during EUS.

A Comparative Study of Esketamine-Propofol and Sufentanil-Propofol for Analgesia and Sedation During Breast Minimally Invasive Rotary Resection with Local Anesthesia: A Randomized Double-Blind Clinical Trial

Purpose

Minimally invasive rotary resection (MIRR) is crucial for diagnosing and treating breast tumors, but the optimal intravenous anesthesia regimen is unclear. Esketamine, an NMDA receptor antagonist with anesthetic, analgesic, and sympathomimetic properties, may provide an ideal adjunct to propofol sedation. This study aims to compare the safety and efficacy of esketamine versus sufentanil as adjuncts to propofol for analgesia and sedation during breast MIRR.

Patients and Methods

A total of 90 patients undergoing elective breast MIRR were randomly assigned to receive either sufentanil-propofol or esketamine-propofol for analgesia and sedation. The primary outcome was the occurrence of hypoxia (SpO2 < 92% for >10s or exhibiting a persistent downward trajectory). Other outcomes included incidence of subclinical respiratory depression (92% ≤ SpO2 < 95% for >10s), number of airway interventions, awakening time, satisfaction scores, postoperative exhaust time, hemodynamic parameters, and side events.

Results

Finally, 41 patients were assigned to the sufentanil group and 40 to the esketamine group. The occurrence of hypoxia was significantly lower in the esketamine group (17.5%) than in the sufentanil group (39%) (P = 0.032). Subclinical respiratory depression occurred in 32.5% of the esketamine group and 56.1% of the sufentanil group (P = 0.033). The sufentanil group required more airway interventions than the esketamine group (P = 0.032), and patients in the sufentanil group experiencing hypoxia received more mask-assisted ventilation (P = 0.029). Hemodynamic stability was better in the esketamine group. No significant differences were observed in awakening time, satisfaction score, postoperative exhaust time, or side events between groups.

Conclusion

Esketamine-propofol anesthesia significantly reduces the risk of hypoxia (SpO2 < 92%) compared to sufentanil-propofol, while maintaining similar awakening time, satisfaction, postoperative exhaust time, and side events. Its hemodynamic advantages make it valuable for clinical use, especially in procedures requiring respiratory and hemodynamic stability.

Psychiatric Disorders in Patients with Chronic Obstructive Pulmonary Disease: Clinical Significance and Treatment Strategies

Chronic obstructive pulmonary disease (COPD) is a debilitating lung disease characterized by chronic airflow limitation and persistent respiratory symptoms. It is a major cause of morbidity and mortality worldwide, significantly impacting healthcare systems with considerable socioeconomic consequences. The main risk factors include exposure to tobacco smoke, environmental pollutants, occupational dust, and genetic factors such as alpha-1 antitrypsin deficiency. COPD is often associated with extrapulmonary comorbidities, particularly psychiatric disorders like depression and anxiety, which worsen patients' quality of life and prognosis. The prevalence of these disorders in patients with COPD varies significantly but is always higher than in healthy controls. Psychiatric disorders can negatively influence COPD management and vice versa, creating a complex bidirectional interaction. Depression and anxiety are the most common psychiatric comorbidities in patients with COPD, influenced by factors such as social isolation, physical limitations, and fear of exacerbations. Diagnosis of these psychiatric disorders is complicated by the overlap of symptoms with those of COPD. However, some screening tools can facilitate early detection. The treatment of psychiatric disorders in patients with COPD in a rehabilitation setting requires a multidisciplinary approach involving pulmonologists, neurologists and psychologists. Pharmacological therapy with antidepressants shows mixed results in terms of efficacy and safety, with some studies reporting benefits on quality of life and others suggesting an increased risk of exacerbations and pneumonia. An integrated approach that includes the assessment and intervention of mental disorders is essential to improve the overall management of COPD and the quality of life of patients. This narrative review provides an overview of the main psychiatric comorbidities in COPD patients, aiming to fill gaps in the literature and suggest areas for future research.

Serotonin therapies for opioid-induced disordered swallow and respiratory depression

Opioids are well-known to cause respiratory depression, but despite clinical evidence of dysphagia, the effects of opioids on swallow excitability and motor pattern are unknown. We tested the effects of the clinically relevant opioid buprenorphine on pharyngeal swallow and respiratory drive in male and female rats. We also evaluated the utility of 5-HT1A agonists (8-OH-DPAT and buspirone) to improve swallowing and breathing following buprenorphine administration. Experiments were performed on 44 freely breathing Sprague-Dawley rats anesthetized with sodium pentobarbital. Bipolar fine wire electrodes were inserted into the mylohyoid, thyroarytenoid, posterior cricoarytenoid, thyropharyngeus, and diaphragm muscles to measure electromyographic (EMG) activity of swallowing and breathing. We evaluated the hypotheses that swallowing varies by stimulus, opioids depress swallowing and breathing, and that 5-HT1A agonists improve these depressions. Our results largely confirmed the following hypotheses: 1) swallow-related EMG activity was larger during swallows elicited by esophageal distension plus oral water infusion than by either stimulus alone. 2) Buprenorphine depressed swallow in both sexes, but females were more susceptible to total swallow suppression. 3) Female animals were also more vulnerable to opioid-induced respiratory depression. 4) 8-OH-DPAT rescued breathing following buprenorphine-induced respiratory arrest, and pretreatment with the partial 5-HT1A agonist buspirone prevented buprenorphine-induced respiratory arrest in female animals. 5) 8-OH-DPAT enhanced mylohyoid and thyropharyngeus EMG amplitude during swallow but did not restore excitability of the swallow pattern generator following total suppression by buprenorphine. Our results highlight sex-specific and behavior-specific effects of buprenorphine and provide preclinical evidence of a 5HT1A agonist for the treatment of respiratory depression and dysphagia.NEW & NOTEWORTHY This is the first study, to our knowledge, to evaluate sex-specific effects of opioid administration on pharyngeal swallow. We expand on a small but growing number of studies that report a lower threshold for opioid-induced respiratory depression in females compared with males, and we are the first to produce this effect with the partial μ-opioid-receptor agonist buprenorphine. This is the first demonstration, to our knowledge, that activation of 5-HT1A receptors can improve swallow and breathing outcomes following systemic buprenorphine administration.

Brain PET imaging using 11C-flumazenil and 11C-buprenorphine does not support the hypothesis of a mutual interaction between buprenorphine and benzodiazepines at the neuroreceptor level

Among opioids, buprenorphine presents a favorable safety profile with a limited risk of respiratory depression. However, fatalities have been reported when buprenorphine is combined to a benzodiazepine. Potentiation of buprenorphine interaction with opioid receptors (ORs) with benzodiazepines, and/or vice versa, is hypothesized to explain this drug-drug interaction (DDI). The mutual DDI between buprenorphine and benzodiazepines was investigated at the neuroreceptor level in nonhuman primates (n = 4 individuals) using brain PET imaging and kinetic modelling. The binding potential (BPND) of benzodiazepine receptor (BzR) was assessed using 11C-flumazenil PET imaging before and after administration of buprenorphine (0.2 mg, i.v.). Moreover, the brain kinetics and receptor binding of buprenorphine were investigated in the same individuals using 11C-buprenorphine PET imaging before and after administration of diazepam (10 mg, i.v.). Outcome parameters were compared using a two-way ANOVA. Buprenorphine did not impact the plasma nor brain kinetics of 11C-flumazenil. 11C-flumazenil BPND was unchanged following buprenorphine exposure, in any brain region (p > 0.05). Similarly, diazepam did not impact the plasma or brain kinetics of 11C-buprenorphine. 11C-buprenorphine volume of distribution (VT) was unchanged following diazepam exposure, in any brain region (p > 0.05). To conclude, our PET imaging findings do not support a neuropharmacokinetic or neuroreceptor-related mechanism of the buprenorphine/benzodiazepine interaction.

Transferring an extremely premature infant to an extra-uterine life support system: a prospective view on the obstetric procedure

To improve care for extremely premature infants, the development of an extrauterine environment for newborn development is being researched, known as Artificial Placenta and Artificial Womb (APAW) technology. APAW facilitates extended development in a liquid-filled incubator with oxygen and nutrient supply through an oxygenator connected to the umbilical vessels. This setup is intended to provide the optimal environment for further development, allowing further lung maturation by delaying gas exposure to oxygen. This innovative treatment necessitates interventions in obstetric procedures to transfer an infant from the native to an artificial womb, while preventing fetal-to-neonatal transition. In this narrative review we analyze relevant fetal physiology literature, provide an overview of insights from APAW studies, and identify considerations for the obstetric procedure from the native uterus to an APAW system. Lastly, this review provides suggestions to improve sterility, fetal and maternal well-being, and the prevention of neonatal transition.

Sleep disorders in chronic pain and its neurochemical mechanisms: a narrative review

Chronic pain (CP) is a prevalent problem, and more than half of patients with CP have sleep disorders. CP comorbidity with sleep disorders imposes immense suffering and seriously affects the patient's quality of life, which is a challenging issue encountered by clinicians. Although the reciprocal interactions between pain and sleep have been studied to some degree, there is still a lack of awareness and comprehensive description of CP comorbidity with sleep disorders. In this narrative review article, we summarize the current knowledge about the present estimates of the prevalence of comorbid sleep disorders in CP patients, sleep detection methods, sleep characterization in CP, and the effect of sleep disorders on CP and current therapies. We also summarize current knowledge of the neurochemical mechanisms of CP comorbidity with sleep disorders. In conclusion, insufficient attention has been paid to the role of sleep disorders in CP patients, and CP patients should be screened for sleep disorders in the clinic. Special attention should be given to a possible risk of drug-drug interaction when using two types of drugs targeting pain and sleep simultaneously. The current insight into the neurobiological mechanisms underlying CP comorbidity with sleep disorders is still rather limited.

Efficacy and Safety of a Subanesthetic Dose of Esketamine Combined with Propofol in Patients with Obesity Undergoing Painless Gastroscopy: A Prospective, Double-Blind, Randomized Controlled Trial

Purpose

Patients with obesity are more susceptible to hypoxemia. Anesthetic management for patients with obesity undergoing painless gastroscopy presents a severe challenge for anesthesiologists. Esketamine is a NMDA antagonist that has been proven to be beneficial for ameliorating respiratory depression owing to its sympathomimetic effect; however, there are no relevant reports on its use in patients with obesity. We designed a randomized controlled trial to evaluate whether esketamine can be the ideal adjuvant to propofol sedation in patients with obesity undergoing painless gastroscopy.

Patients and Methods

A total of 104 patients with obesity undergoing painless gastroscopy were randomly divided into group C (propofol+saline) and group S (propofol+esketamine 0.25 mg/kg). Anesthesia was induced by 2 mg/kg propofol with saline or esketamine. The consumption of propofol, hemodynamic parameters, duration of procedure, induction time, postoperative awakening time, and orientation recovery time were recorded. Adverse events and satisfaction scores were also recorded.

Results

Propofol consumption was 274.4±22.6 mg and 201.3±16.6 mg in groups C and S, respectively. The induction time of groups C and S were 25.4±2.3 s and 17.8±1.9 s, respectively. The postoperative awakening times of groups C and S were 6.2±1.1 min and 4.8±1.3 min, respectively. Hemodynamic parameters were more stable in group S than in group C. The incidence of adverse events such as injection pain, hypoxemia, hypotension, bradycardia, choking, and body movement were significantly lower in group S. The satisfaction scores of the endoscopist and anesthesiologist were (4.58±0.49 vs 3.71±0.83) and (4.75±0.44 vs 3.33±0.92), respectively.

Conclusion

The combination of propofol and esketamine (0.25 mg/kg) improves the safety and reduces the incidence of adverse events in patients with obesity during painless gastroscopy. Thus, this method is worthy of clinical application.

Clinical Trials Registration

ChiCTR 2200062547.

Suboxone: History, controversy, and open questions

There are more than 200 opioid overdose deaths each day in the US. In combating this epidemic we look to available treatment tools. Here, we find only three medications approved by the Food and Drug Administration (FDA) for the treatment of opioid use disorder. Of the three, buprenorphine is of particular importance due to its reduced overdose potential as a partial opioid agonist. Evidence supports its clinical equivalence to its full agonist cousin methadone, and suggests that it is better slated for long-term treatment of opioid use disorder compared to the non-selective opioid antagonist naltrexone. Buprenorphine is most popularized within Suboxone, a medication which also contains the non-selective opioid antagonist naloxone. The naloxone has no additional effect when the drug is taken as instructed, as it is intended to prevent diversion in those that would attempt to inject the medication. While Suboxone is regarded by some as the future of medical treatment, others have expressed concerns. This review aims to explore the history, controversy, and open questions that surround buprenorphine and its most prescribed variation, Suboxone. These include its pharmacological, legislative, and social history, alternative indications, efficacy as a treatment of opioid use disorder, and more. Armed with this information, the reader will have a more in-depth and holistic understanding of the medication's place in their community.