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Cell Nov 2022Morphine and fentanyl are among the most used opioid drugs that confer analgesia and unwanted side effects through both G protein and arrestin signaling pathways of...
Morphine and fentanyl are among the most used opioid drugs that confer analgesia and unwanted side effects through both G protein and arrestin signaling pathways of μ-opioid receptor (μOR). Here, we report structures of the human μOR-G protein complexes bound to morphine and fentanyl, which uncover key differences in how they bind the receptor. We also report structures of μOR bound to TRV130, PZM21, and SR17018, which reveal preferential interactions of these agonists with TM3 side of the ligand-binding pocket rather than TM6/7 side. In contrast, morphine and fentanyl form dual interactions with both TM3 and TM6/7 regions. Mutations at the TM6/7 interface abolish arrestin recruitment of μOR promoted by morphine and fentanyl. Ligands designed to reduce TM6/7 interactions display preferential G protein signaling. Our results provide crucial insights into fentanyl recognition and signaling of μOR, which may facilitate rational design of next-generation analgesics.
Topics: Humans; Analgesics, Opioid; Arrestin; Fentanyl; GTP-Binding Proteins; Morphine; Receptors, Opioid, mu
PubMed: 36368306
DOI: 10.1016/j.cell.2022.09.041 -
Pharmacogenomics Apr 2021Oxycodone is a semisynthetic μ- and κ-opioid receptor with agonist with a broad scope of use including postoperative analgesia as well as control of neuropathic and... (Review)
Review
Oxycodone is a semisynthetic μ- and κ-opioid receptor with agonist with a broad scope of use including postoperative analgesia as well as control of neuropathic and cancer pain. Advantages over other opioids include prolonged duration of action, greater potency than morphine and lack of histamine release or ceiling effect. Individual responses to oxycodone can vary due to genetic differences. This review article aims to summarize the oxycodone literature and provide context on its pharmacogenomics and pharmacokinetics. The evidence for clinical effect of genetic polymorphisms on oxycodone is conflicting. There is stronger evidence linking polymorphic genetic enzymes CYP2D6 and CYP3A with therapeutic outcomes. Further, research is needed to discern all of oxycodone's metabolites and their contribution to the overall analgesic effect.
Topics: Analgesics, Opioid; Cytochrome P-450 CYP2D6; Cytochrome P-450 CYP3A; Humans; Morphine; Oxycodone; Pharmacogenetics; Polymorphism, Genetic
PubMed: 33728947
DOI: 10.2217/pgs-2020-0143 -
JAMA Nov 2022Chronic breathlessness is common in people with chronic obstructive pulmonary disease (COPD). Regular, low-dose, extended-release morphine may relieve breathlessness,... (Randomized Controlled Trial)
Randomized Controlled Trial
IMPORTANCE
Chronic breathlessness is common in people with chronic obstructive pulmonary disease (COPD). Regular, low-dose, extended-release morphine may relieve breathlessness, but evidence about its efficacy and dosing is needed.
OBJECTIVE
To determine the effect of different doses of extended-release morphine on worst breathlessness in people with COPD after 1 week of treatment.
DESIGN, SETTING, AND PARTICIPANTS
Multicenter, double-blind, placebo-controlled randomized clinical trial including people with COPD and chronic breathlessness (defined as a modified Medical Research Council score of 3 to 4) conducted at 20 centers in Australia. People were enrolled between September 1, 2016, and November 20, 2019, and followed up through December 26, 2019.
INTERVENTIONS
People were randomized 1:1:1 to 8 mg/d or 16 mg/d of oral extended-release morphine or placebo during week 1. At the start of weeks 2 and 3, people were randomized 1:1 to 8 mg/d of extended-release morphine, which was added to the prior week's dose, or placebo.
MAIN OUTCOMES AND MEASURES
The primary outcome was change in the intensity of worst breathlessness on a numerical rating scale (score range, 0 [none] to 10 [being worst or most intense]) using the mean score at baseline (from days -3 to -1) to the mean score after week 1 of treatment (from days 5 to 7) in the 8 mg/d and 16 mg/d of extended-release morphine groups vs the placebo group. Secondary outcomes included change in daily step count measured using an actigraphy device from baseline (day -1) to the mean step count from week 3 (from days 19 to 21).
RESULTS
Among the 160 people randomized, 156 were included in the primary analyses (median age, 72 years [IQR, 67 to 78 years]; 48% were women) and 138 (88%) completed treatment at week 1 (48 in the 8 mg/d of morphine group, 43 in the 16 mg/d of morphine group, and 47 in the placebo group). The change in the intensity of worst breathlessness at week 1 was not significantly different between the 8 mg/d of morphine group and the placebo group (mean difference, -0.3 [95% CI, -0.9 to 0.4]) or between the 16 mg/d of morphine group and the placebo group (mean difference, -0.3 [95%, CI, -1.0 to 0.4]). At week 3, the secondary outcome of change in mean daily step count was not significantly different between the 8 mg/d of morphine group and the placebo group (mean difference, -1453 [95% CI, -3310 to 405]), between the 16 mg/d of morphine group and the placebo group (mean difference, -1312 [95% CI, -3220 to 596]), between the 24 mg/d of morphine group and the placebo group (mean difference, -692 [95% CI, -2553 to 1170]), or between the 32 mg/d of morphine group and the placebo group (mean difference, -1924 [95% CI, -47 699 to 921]).
CONCLUSIONS AND RELEVANCE
Among people with COPD and severe chronic breathlessness, daily low-dose, extended-release morphine did not significantly reduce the intensity of worst breathlessness after 1 week of treatment. These findings do not support the use of these doses of extended-release morphine to relieve breathlessness.
TRIAL REGISTRATION
ClinicalTrials.gov Identifier: NCT02720822.
Topics: Aged; Female; Humans; Male; Delayed-Action Preparations; Double-Blind Method; Dyspnea; Morphine; Pulmonary Disease, Chronic Obstructive; Respiratory System Agents; Chronic Disease; Treatment Outcome
PubMed: 36413230
DOI: 10.1001/jama.2022.20206 -
European Journal of Heart Failure Oct 2022Benzodiazepines have been used as safe anxiolytic drugs for decades and some authors have suggested they could be an alternative for morphine for treating acute... (Randomized Controlled Trial)
Randomized Controlled Trial
AIMS
Benzodiazepines have been used as safe anxiolytic drugs for decades and some authors have suggested they could be an alternative for morphine for treating acute cardiogenic pulmonary oedema (ACPE). We compared the efficacy and safety of midazolam and morphine in patients with ACPE.
METHODS AND RESULTS
A randomized, multicentre, open-label, blinded endpoint clinical trial was performed in seven Spanish emergency departments (EDs). Patients >18 years old clinically diagnosed with ACPE and with dyspnoea and anxiety were randomized (1:1) at ED arrival to receive either intravenous midazolam or morphine. Efficacy was assessed by in-hospital all-cause mortality (primary endpoint). Safety was assessed through serious adverse event (SAE) reporting, and the composite endpoint included 30-day mortality and SAE. Analyses were made on an intention-to-treat basis. The trial was stopped early after a planned interim analysis by the safety monitoring committee. At that time, 111 patients had been randomized: 55 to midazolam and 56 to morphine. There were no significant differences in the primary endpoint (in-hospital mortality for midazolam vs. morphine 12.7% vs. 17.9%; risk ratio[RR] 0.71, 95% confidence interval [CI] 0.29-1.74; p = 0.60). SAE were less common with midazolam versus morphine (18.2% vs. 42.9%; RR 0.42, 95% CI 0.22-0.80; p = 0.007), as were the composite endpoint (23.6% vs. 44.6%; RR 0.53, 95% CI 0.30-0.92; p = 0.03).
CONCLUSION
Although the number of patients was too small to draw final conclusions and there were no significant differences in mortality between midazolam and morphine, a significantly higher rate of SAEs was found in the morphine group.
Topics: Humans; Adolescent; Midazolam; Morphine; Pulmonary Edema; Heart Failure; Hospital Mortality
PubMed: 35780488
DOI: 10.1002/ejhf.2602 -
Anesthesiology Jun 2020Intrathecal opioids are routinely administered during spinal anesthesia for postcesarean analgesia. The effectiveness of intrathecal morphine for postcesarean analgesia... (Comparative Study)
Comparative Study Randomized Controlled Trial
BACKGROUND
Intrathecal opioids are routinely administered during spinal anesthesia for postcesarean analgesia. The effectiveness of intrathecal morphine for postcesarean analgesia is well established, and the use of intrathecal hydromorphone is growing. No prospective studies have compared the effectiveness of equipotent doses of intrathecal morphine versus intrathecal hydromorphone as part of a multimodal analgesic regimen for postcesarean analgesia. The authors hypothesized that intrathecal morphine would result in superior analgesia compared with intrathecal hydromorphone 24 h after delivery.
METHODS
In this single-center, double-blinded, randomized trial, 138 parturients undergoing scheduled cesarean delivery were randomized to receive 150 µg of intrathecal morphine or 75 µg of intrathecal hydromorphone as part of a primary spinal anesthetic and multimodal analgesic regimen; 134 parturients were included in the analysis. The primary outcome was the numerical rating scale score for pain with movement 24 h after delivery. Static and dynamic pain scores, nausea, pruritus, degree of sedation, and patient satisfaction were assessed every 6 h for 36 h postpartum. Total opioid consumption was recorded.
RESULTS
There was no significant difference in pain scores with movement at 24 h (intrathecal hydromorphone median [25th, 75th] 4 [3, 5] and intrathecal morphine 3 [2, 4.5]) or at any time point (estimated difference, 0.5; 95% CI, 0 to 1; P = 0.139). Opioid received in the first 24 h did not differ between groups (median [25th, 75th] oral morphine milligram equivalents for intrathecal hydromorphone 30 [7.5, 45.06] vs. intrathecal morphine 22.5 [14.0, 37.5], P = 0.769). From Kaplan-Meier analysis, the median time to first opioid request was 5.4 h for hydromorphone and 12.1 h for morphine (log-rank test P = 0.200).
CONCLUSIONS
Although the hypothesis was that intrathecal morphine would provide superior analgesia to intrathecal hydromorphone, the results did not confirm this. At the doses studied, both intrathecal morphine and intrathecal hydromorphone provide effective postcesarean analgesia when combined with a multimodal analgesia regimen.
Topics: Adult; Analgesia, Epidural; Analgesia, Obstetrical; Analgesics, Opioid; Cesarean Section; Double-Blind Method; Female; Humans; Hydromorphone; Male; Morphine; Pain, Postoperative; Treatment Outcome
PubMed: 32251031
DOI: 10.1097/ALN.0000000000003283 -
Ugeskrift For Laeger Jan 2024Chronic malignant pain is a common and feared condition. Especially, since many patients do not achieve proper pain relief from conventional peroral medication regimes... (Review)
Review
Chronic malignant pain is a common and feared condition. Especially, since many patients do not achieve proper pain relief from conventional peroral medication regimes and possible unacceptable side effects of high dosing. As argued in this review, in these patients, continuous intrathecal infusion of pain medicine by a programmable subcutaneously placed pump enables good pain relief, less systemic side effects, and better life quality. Intrathecal pain treatment should therefore be considered in patients with a proper performance score and suitable estimated life expectancy.
Topics: Humans; Morphine; Analgesics; Palliative Care; Pain Management; Pain; Chronic Pain
PubMed: 38305326
DOI: 10.61409/V08230541 -
Pharmacology, Biochemistry, and Behavior Jul 2022Ovarian hormones influence the activity of endogenous opioids, and exogenous administration of estradiol reduces opioid intake and opioid seeking in animal models of...
Ovarian hormones influence the activity of endogenous opioids, and exogenous administration of estradiol reduces opioid intake and opioid seeking in animal models of opioid reward and reinforcement. The purpose of this study was to examine the effects of ovarian hormones on the discriminative stimulus effects of morphine and naloxone-precipitated opioid withdrawal. To this end, separate groups of ovariectomized female rats were trained to discriminate the stimulus effects of either 3.0 or 10 mg/kg morphine, and substitution tests were conducted with estradiol or progesterone alone and in combination with morphine. At the conclusion of discrimination testing, rats were treated chronically with estradiol, progesterone, or their combination, and challenged with naloxone to measure opioid-like withdrawal symptoms. Finally, the effects of estradiol, progesterone, and their combination were examined on naloxone-precipitated withdrawal in morphine-dependent rats. Neither estradiol nor progesterone substituted for the morphine discriminative stimulus, but estradiol significantly increased the potency of morphine in rats trained to discriminate 10 mg/kg but not 3 mg/kg morphine. When administered chronically, neither hormone nor their combination produced an opioid-like withdrawal syndrome following a naloxone challenge. Acute administration of estradiol, but not progesterone or a combination of estradiol and progesterone, significantly reduced naloxone-precipitated weight loss in morphine-dependent rats. These data indicate that estradiol influences the behavioral effects of morphine, possibly by increasing endogenous tone at mu opioid receptors.
Topics: Analgesics, Opioid; Animals; Estradiol; Female; Morphine; Morphine Dependence; Naloxone; Narcotic Antagonists; Progesterone; Rats; Receptors, Opioid, mu; Substance Withdrawal Syndrome; Substance-Related Disorders
PubMed: 35850178
DOI: 10.1016/j.pbb.2022.173431 -
Molecules (Basel, Switzerland) Apr 20226,14-ethenomorphinans are semisynthetic opiate derivatives containing an ethylene bridge between positions 6 and 14 in ring-C of the morphine skeleton that imparts a... (Review)
Review
6,14-ethenomorphinans are semisynthetic opiate derivatives containing an ethylene bridge between positions 6 and 14 in ring-C of the morphine skeleton that imparts a rigid molecular structure. These compounds represent an important family of opioid receptor ligands in which the 6,14-etheno bridged structural motif originates from a [4 + 2] cycloaddition of morphinan-6,8-dienes with dienophiles. Certain 6,14-ethenomorphinans having extremely high affinity for opioid receptors are often non-selective for opioid receptor subtypes, but this view is now undergoing some revision. The agonist 20-etorphine and 20-dihydroetorphine are several thousand times more potent analgesics than morphine, whereas diprenorphine is a high-affinity non-selective antagonist. The partial agonist buprenorphine is used as an analgesic in the management of post-operative pain or in substitution therapy for opiate addiction, sometimes in combination with the non-selective antagonist naloxone. In the context of the current opioid crisis, we communicated a summary of several decades of work toward generating opioid analgesics with lesser side effects or abuse potential. Our summary placed a focus on Diels-Alder reactions of morphinan-6,8-dienes and subsequent transformations of the cycloadducts. We also summarized the pharmacological aspects of radiolabeled 6,14-ethenomorphinans used in molecular imaging of opioid receptors.
Topics: Analgesics; Analgesics, Opioid; Morphinans; Morphine; Naloxone; Receptors, Opioid; Receptors, Opioid, mu
PubMed: 35566212
DOI: 10.3390/molecules27092863 -
Journal of the American College of... Sep 2022Single-shot intrathecal morphine (ITM) is an effective strategy for postoperative analgesia, but there are limited data on its safety, efficacy, and relationship with...
BACKGROUND
Single-shot intrathecal morphine (ITM) is an effective strategy for postoperative analgesia, but there are limited data on its safety, efficacy, and relationship with functional recovery among patients undergoing pancreaticoduodenectomy.
STUDY DESIGN
This was a retrospective review of patients undergoing pancreaticoduodenectomy from 2014 to 2020 as identified by the institutional NSQIP Hepato-pancreato-biliary database. Patients were categorized by having received no spinal analgesia, ITM, or ITM with transversus abdominus plane block (ITM+TAP). The primary outcomes were average daily pain scores from postoperative days (POD) 0 to 3, total morphine equivalents (MEQ) consumed over POD 0 to 3, and average daily inpatient MEQ from POD 4 to discharge. Secondary outcomes included the incidence of opioid related complications, length of stay, and functional recovery.
RESULTS
A total of 233 patients with a median age of 67 years were included. Of these, 36.5% received no spinal analgesia, 49.3% received ITM, and 14.2% received ITM+TAP. Average pain scores in POD 0 to 3 were similar by mode of spinal analgesia (none [2.8], ITM [2.6], ITM+TAP [2.3]). Total MEQ consumed from POD 0 to 3 were lower for patients who received ITM (121 mg) and ITM+TAP (132 mg), compared with no spinal analgesia (232 mg) (p < 0.0001). Average daily MEQ consumption from POD 4 to discharge was lower for ITM (18 mg) and ITM+TAP (13.1 mg) cohorts compared with no spinal analgesia (32.9 mg) (p = 0.0016). Days to functional recovery and length of stay were significantly reduced for ITM and ITM+TAP compared with no spinal analgesia. These findings remained consistent through multivariate analysis, and there were no differences in opioid-related complications among cohorts.
CONCLUSIONS
ITM was associated with reduced early postoperative and total inpatient opioid utilization, days to functional recovery, and length of stay among patients undergoing pancreaticoduodenectomy. ITM is a safe and effective form of perioperative analgesia that may benefit patients undergoing pancreaticoduodenectomy.
Topics: Aged; Analgesics, Opioid; Humans; Injections, Spinal; Morphine; Pain Measurement; Pain, Postoperative; Pancreaticoduodenectomy
PubMed: 35758927
DOI: 10.1097/XCS.0000000000000261 -
Journal of Traditional Chinese Medicine... Oct 2023To evaluate the effect of berberine on morphine analgesia, tolerance, and hyperalgesia.
OBJECTIVE
To evaluate the effect of berberine on morphine analgesia, tolerance, and hyperalgesia.
METHODS
Morphine-induced acute tolerance model: mice received intraperitoneal berberine at doses of 2.5, 5.0, and 10 mg/kg; 30 min later, subcutaneous morphine 10 mg/kg was injected every hour for nine continuous h. Morphine 10 mg/kg alone was administered at 24 and 48 h. Morphine-induced chronic tolerance model: mice received intraperitoneal berberine 2.5, 5.0, and 10 mg/kg; 30 min later, 10 mg/kg morphine was injected subcutaneously for eight consecutive days. On the ninth day, morphine 10 mg/kg was given alone. Morphine-induced established tolerance model: mice were injected subcutaneously with morphine 10 mg/kg once a day for eight consecutive days. Berberine 2.5 mg/kg was administered on day one, four, and seven and morphine 10 mg/kg alone on day nine. The baseline latency (T0) and post-treatment latency (T1) were determined by the hot plate test, and the maximum possible analgesic effect (MPAE) was calculated. Nitric oxide synthase (NOS) activity and nitric oxide (NO) content in the spinal cord were measured by spectrophotometer. Verification of berberine analgesic effect by blocking N-methyl-D-aspartate (NMDA) receptor: HT-22 and HEK-293 cells transfected with NMDA plasmid were randomly divided into five groups: control group, NMDA group, berberine low-dose, medium-dose, and high-dose groups (5, 10, 20 μmol/L, respectively). Except for the control group, cells were treated with NMDA (HT-22 cells: 20 mmol/L; HEK-293 cells: 50 μmol/L). After 24 h, cell viability was detected by cell counting kit-8. The molecular mechanism between berberine and the NMDA receptor was studied by molecular docking.
RESULTS
Berberine 2.5 and 5.0 mg/kg could prolong the analgesic time of morphine. In acute and chronic morphine tolerance models, berberine could inhibit the decrease of MPAE and baseline latency (0.05). In the established tolerance model, berberine could rapidly reverse the decreased MPAE (0.05). The combination of berberine and morphine on day one could effectively inhibit the morphine-induced increase of NOS activity and NO content in the spinal cord (0.05). Berberine significantly increased the cell viability of NMDA-induced nerve injury in HT-22 and HEK-293 cells (0.05). Molecular docking showed that berberine binds to the receptor pocket of NMDA.
CONCLUSIONS
Berberine could effectively enhance and prolong the duration of morphine analgesia and inhibit the development of morphine-induced tolerance and hyperalgesia. Furthermore, berberine has a certain neuroprotective effect, which may be related to the inhibition of NMDA activity.
Topics: Humans; Animals; Mice; Hyperalgesia; Morphine; Berberine; HEK293 Cells; Molecular Docking Simulation; N-Methylaspartate; Nitric Oxide
PubMed: 37679979
DOI: 10.19852/j.cnki.jtcm.20230802.006