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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 -
Science Advances Jun 2023The association between rewarding and drug-related memory is a leading factor for the formation of addiction, yet the neural circuits underlying the association remain...
The association between rewarding and drug-related memory is a leading factor for the formation of addiction, yet the neural circuits underlying the association remain unclear. Here, we showed that the interstitial nucleus of the posterior limb of the anterior commissure (IPAC) integrated rewarding and environmental memory information by two different receiving projections from ventral tegmental area (VTA) and nucleus accumbens shell region (NAcSh) to mediate the acquisition of morphine conditioned place preference (CPP). A projection from the VTA GABAergic neurons (VTA) to the IPAC lateral region GABAergic neurons (IPACL) mediated the effect of morphine rewarding, whereas the pathway from NAcSh dopamine receptor 1-expressing neurons (NAcSh) to the IPAC medial region GABAergic neurons (IPACM) was involved in the acquisition of environmental memory. These findings demonstrated that the distinct IPAC circuits VTAIPACL and NAcShIPACM were attributable to the rewarding and environmental memory during the acquisition of morphine CPP, respectively, and provided the circuit-based potential targets for preventing and treating opioid addiction.
Topics: Morphine; Ventral Tegmental Area; Reward; GABAergic Neurons; gamma-Aminobutyric Acid
PubMed: 37352353
DOI: 10.1126/sciadv.adg5849 -
Clinical Pharmacology and Therapeutics Mar 2021Nonalcoholic steatohepatitis (NASH), the progressive form of nonalcoholic fatty liver disease, is increasing in prevalence. NASH-related alterations in hepatic protein...
Nonalcoholic steatohepatitis (NASH), the progressive form of nonalcoholic fatty liver disease, is increasing in prevalence. NASH-related alterations in hepatic protein expression (e.g., transporters) and in overall physiology may affect drug exposure by altering drug disposition and elimination. The aim of this study was to build a physiologically-based pharmacokinetic (PBPK) model to predict drug exposure in NASH by incorporating NASH-related changes in hepatic transporters. Morphine and morphine-3-glucuronide (M3G) were used as model compounds. A PBPK model of morphine with permeability-limited hepatic disposition was extended to include M3G disposition and enterohepatic recycling (EHR). The model captured the area under the plasma concentration-time curve (AUC) of morphine and M3G after intravenous morphine administration within 0.82-fold and 1.94-fold of observed values from 3 independent clinical studies for healthy adult subjects (6, 10, and 14 individuals). When NASH-related changes in multidrug resistance-associated protein 2 (MRP2) and MRP3 were incorporated into the model, the predicted M3G mean AUC in NASH was 1.34-fold higher compared to healthy subjects, which is slightly lower than the observed value (1.63-fold). Exploratory simulations on other physiological changes occurring in NASH (e.g., moderate decreases in glomerular filtration rate and portal vein blood flow) revealed that the effect of transporter changes was most prominent. Additionally, NASH-related transporter changes resulted in decreased morphine EHR, which could be important for drugs with extensive EHR. This study is an important first step to predict drug disposition in complex diseases such as NASH using PBPK modeling.
Topics: Administration, Intravenous; Analgesics, Opioid; Case-Control Studies; Computer Simulation; Humans; Liver; Metabolic Detoxication, Phase II; Models, Biological; Morphine Derivatives; Multidrug Resistance-Associated Protein 2; Multidrug Resistance-Associated Proteins; Non-alcoholic Fatty Liver Disease
PubMed: 32897538
DOI: 10.1002/cpt.2037 -
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 -
Assessment of the potential of novel and classical opioids to induce respiratory depression in mice.British Journal of Pharmacology Dec 2023Opioid-induced respiratory depression limits the use of μ-opioid receptor agonists in clinical settings and is the main cause of opioid overdose fatalities. The...
BACKGROUND AND PURPOSE
Opioid-induced respiratory depression limits the use of μ-opioid receptor agonists in clinical settings and is the main cause of opioid overdose fatalities. The relative potential of different opioid agonists to induce respiratory depression at doses exceeding those producing analgesia is understudied despite its relevance to assessments of opioid safety. Here we evaluated the respiratory depressant and anti-nociceptive effects of three novel opioids and relate these measurements to their in vitro efficacy.
EXPERIMENTAL APPROACH
Respiration was measured in awake, freely moving male CD-1 mice using whole body plethysmography. Anti-nociception was measured using the hot plate test. Morphine, oliceridine and tianeptine were administered intraperitoneally, whereas methadone, oxycodone and SR-17018 were administered orally. Receptor activation and arrestin-3 recruitment were measured in HEK293 cells using BRET assays.
KEY RESULTS
Across the dose ranges examined, all opioids studied depressed respiration in a dose-dependent manner, with similar effects at the highest doses, and with tianeptine and oliceridine showing reduced duration of effect, when compared with morphine, oxycodone, methadone and SR-17018. When administered at doses that induced similar respiratory depression, all opioids induced similar anti-nociception, with tianeptine and oliceridine again showing reduced duration of effect. These data were consistent with the in vitro agonist activity of the tested compounds.
CONCLUSION AND IMPLICATIONS
In addition to providing effective anti-nociception, the novel opioids, oliceridine, tianeptine and SR-17018 depress respiration in male mice. However, the different potencies and kinetics of effect between these novel opioids may be relevant to their therapeutic application in different clinical settings.
Topics: Male; Humans; Animals; Mice; Analgesics, Opioid; Oxycodone; HEK293 Cells; Morphine; Respiratory Insufficiency; Methadone
PubMed: 37489013
DOI: 10.1111/bph.16199