-
Kidney International Apr 2015Uremic pruritus or chronic kidney disease-associated pruritus (CKD-aP) remains a frequent and compromising symptom in patients with advanced or end-stage renal disease,... (Review)
Review
Uremic pruritus or chronic kidney disease-associated pruritus (CKD-aP) remains a frequent and compromising symptom in patients with advanced or end-stage renal disease, strongly reducing the patient's quality of life. More than 40% of patients undergoing hemodialysis suffer from chronic pruritus; half of them complain about generalized pruritus. The pathogenesis of CKD-aP remains obscure. Parathormone and histamine as well as calcium and magnesium salts have been suspected as pathogenetic factors. Newer hypotheses are focusing on opioid-receptor derangements and microinflammation as possible causes of CKD-aP, although until now this could not be proven. Pruritus may be extremely difficult to control, as therapeutic options are limited. The most consequential approaches to treatment are: topical treatment with or without anti-inflammatory compounds or systemic treatment with (a) gabapentin, (b) μ-opioid receptor antagonists and κ-agonists, (c) drugs with an anti-inflammatory action, (d) phototherapy, or (e) acupuncture. A stepwise approach is suggested starting with emollients and gabapentin or phototherapy as first-line treatments. In refractory cases, more experimental options as μ-opioid-receptor-antagonists (i.e., naltrexone) or κ-opioid-receptor agonist (nalfurafine) may be chosen. In desperate cases, patients suitable for transplantation might be set on 'high urgency'-status, as successful kidney transplantation will relieve patients from CKD-aP.
Topics: Acupuncture Therapy; Amines; Anti-Inflammatory Agents; Calcium Channel Blockers; Cyclohexanecarboxylic Acids; Gabapentin; Humans; Morphinans; Naltrexone; Narcotic Antagonists; Pentoxifylline; Phototherapy; Pregabalin; Pruritus; Receptors, Opioid, kappa; Renal Insufficiency, Chronic; Spiro Compounds; Tacrolimus; Thalidomide; Uremia; gamma-Aminobutyric Acid; gamma-Linolenic Acid
PubMed: 24402092
DOI: 10.1038/ki.2013.454 -
Nature Jun 2018The μ-opioid receptor (μOR) is a G-protein-coupled receptor (GPCR) and the target of most clinically and recreationally used opioids. The induced positive effects of...
The μ-opioid receptor (μOR) is a G-protein-coupled receptor (GPCR) and the target of most clinically and recreationally used opioids. The induced positive effects of analgesia and euphoria are mediated by μOR signalling through the adenylyl cyclase-inhibiting heterotrimeric G protein G. Here we present the 3.5 Å resolution cryo-electron microscopy structure of the μOR bound to the agonist peptide DAMGO and nucleotide-free G. DAMGO occupies the morphinan ligand pocket, with its N terminus interacting with conserved receptor residues and its C terminus engaging regions important for opioid-ligand selectivity. Comparison of the μOR-G complex to previously determined structures of other GPCRs bound to the stimulatory G protein G reveals differences in the position of transmembrane receptor helix 6 and in the interactions between the G protein α-subunit and the receptor core. Together, these results shed light on the structural features that contribute to the G protein-coupling specificity of the µOR.
Topics: Animals; Binding Sites; Cryoelectron Microscopy; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Female; GTP-Binding Protein alpha Subunits, Gi-Go; GTP-Binding Protein alpha Subunits, Gs; Humans; Ligands; Mice; Mice, Inbred BALB C; Molecular Dynamics Simulation; Morphinans; Protein Stability; Receptors, Adrenergic, beta-2; Receptors, Opioid, mu; Substrate Specificity
PubMed: 29899455
DOI: 10.1038/s41586-018-0219-7 -
Molecules (Basel, Switzerland) Aug 2020Several over-the-counter (OTC) drugs are known to be misused. Among them are opioids such as codeine, dihydrocodeine, and loperamide. This work elucidates their... (Review)
Review
Several over-the-counter (OTC) drugs are known to be misused. Among them are opioids such as codeine, dihydrocodeine, and loperamide. This work elucidates their pharmacology, interactions, safety profiles, and how pharmacology is being manipulated to misuse these common medications, with the aim to expand on the subject outlined by the authors focusing on abuse prevention and prevalence rates. The reviewed literature was identified in several online databases through searches conducted with phrases created by combining the international non-proprietary names of the drugs with terms related to drug misuse. The results show that OTC opioids are misused as an alternative for illicit narcotics, or prescription-only opioids. The potency of codeine and loperamide is strongly dependent on the individual enzymatic activity of CYP2D6 and CYP3A4, as well as P-glycoprotein function. Codeine can also be utilized as a substrate for clandestine syntheses of more potent drugs of abuse, namely desomorphine ("Krokodil"), and morphine. The dangerous methods used to prepare these substances can result in poisoning from toxic chemicals and impurities originating from the synthesis procedure. OTC opioids are generally safe when consumed in accordance with medical guidelines. However, the intake of supratherapeutic amounts of these substances may reveal surprising traits of common medications.
Topics: Analgesics, Opioid; Codeine; Drug Misuse; Humans; Loperamide; Nonprescription Drugs
PubMed: 32867117
DOI: 10.3390/molecules25173905 -
Neuropharmacology Jun 2019Opioid drugs are important tools to alleviate pain of different origins, but they have strong addictive potential and their abuse at higher doses often results in... (Review)
Review
Opioid drugs are important tools to alleviate pain of different origins, but they have strong addictive potential and their abuse at higher doses often results in serious health complications. Respiratory depression that leads to brain hypoxia is perhaps the most dangerous symptom of acute intoxication with opioids, and it could result in lethality. The development of substrate-specific sensors coupled with amperometry made it possible to directly evaluate physiological and drug-induced fluctuations in brain oxygen levels in awake, freely-moving rats. The goal of this review paper is to consider changes in brain oxygen levels induced by several opioid drugs (heroin, fentanyl, oxycodone, morphine). While some of these drugs are widely used in clinical practice, they all are abused, often at doses exceeding the clinical range and often resulting in serious health complications. First, we consider some basic knowledge regarding brain oxygen, its physiological fluctuations, and mechanisms involved in regulating its entry into brain tissue. Then, we present and discuss data on brain oxygen changes induced by each opioid drug within a wide range of doses, from low, behaviorally relevant, to high, likely to be self-administered by drug users. These data allowed us to compare the effects of these drugs on brain oxygen in terms of their potency, time-course, and their potential danger when used at high doses via rapid-onset administration routes. While most data discussed in this work were obtained in rats, we believe that these data have clear human relevance in addressing the alarming rise in lethality associated with the opioid abuse.
Topics: Analgesics, Opioid; Animals; Brain; Fentanyl; Heroin; Humans; Hypoxia, Brain; Morphine; Oxycodone; Rats; Respiratory Insufficiency
PubMed: 30735692
DOI: 10.1016/j.neuropharm.2019.02.008 -
The New England Journal of Medicine Sep 2014The androgen-receptor isoform encoded by splice variant 7 lacks the ligand-binding domain, which is the target of enzalutamide and abiraterone, but remains...
BACKGROUND
The androgen-receptor isoform encoded by splice variant 7 lacks the ligand-binding domain, which is the target of enzalutamide and abiraterone, but remains constitutively active as a transcription factor. We hypothesized that detection of androgen-receptor splice variant 7 messenger RNA (AR-V7) in circulating tumor cells from men with advanced prostate cancer would be associated with resistance to enzalutamide and abiraterone.
METHODS
We used a quantitative reverse-transcriptase-polymerase-chain-reaction assay to evaluate AR-V7 in circulating tumor cells from prospectively enrolled patients with metastatic castration-resistant prostate cancer who were initiating treatment with either enzalutamide or abiraterone. We examined associations between AR-V7 status (positive vs. negative) and prostate-specific antigen (PSA) response rates (the primary end point), freedom from PSA progression (PSA progression-free survival), clinical or radiographic progression-free survival, and overall survival.
RESULTS
A total of 31 enzalutamide-treated patients and 31 abiraterone-treated patients were enrolled, of whom 39% and 19%, respectively, had detectable AR-V7 in circulating tumor cells. Among men receiving enzalutamide, AR-V7-positive patients had lower PSA response rates than AR-V7-negative patients (0% vs. 53%, P=0.004) and shorter PSA progression-free survival (median, 1.4 months vs. 6.0 months; P<0.001), clinical or radiographic progression-free survival (median, 2.1 months vs. 6.1 months; P<0.001), and overall survival (median, 5.5 months vs. not reached; P=0.002). Similarly, among men receiving abiraterone, AR-V7-positive patients had lower PSA response rates than AR-V7-negative patients (0% vs. 68%, P=0.004) and shorter PSA progression-free survival (median, 1.3 months vs. not reached; P<0.001), clinical or radiographic progression-free survival (median, 2.3 months vs. not reached; P<0.001), and overall survival (median, 10.6 months vs. not reached, P=0.006). The association between AR-V7 detection and therapeutic resistance was maintained after adjustment for expression of full-length androgen receptor messenger RNA.
CONCLUSIONS
Detection of AR-V7 in circulating tumor cells from patients with castration-resistant prostate cancer may be associated with resistance to enzalutamide and abiraterone. These findings require large-scale prospective validation. (Funded by the Prostate Cancer Foundation and others.).
Topics: Androstenes; Androstenols; Benzamides; Drug Resistance, Neoplasm; Humans; Male; Morphinans; Nitriles; Phenylthiohydantoin; Prostatic Neoplasms; RNA, Neoplasm; Receptors, Androgen; Reverse Transcriptase Polymerase Chain Reaction; Survival Analysis
PubMed: 25184630
DOI: 10.1056/NEJMoa1315815 -
Frontiers in Immunology 2018Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory arthropathy associated with articular damage and attendant comorbidities. Even although RA treatment has... (Randomized Controlled Trial)
Randomized Controlled Trial
Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory arthropathy associated with articular damage and attendant comorbidities. Even although RA treatment has advanced remarkably over the last decade, a significant proportion of patients still do not achieve sustained remission. The cause of RA is not yet known despite the many potential mechanisms proposed. It has been confirmed that RA is associated with dysregulated immune system and persistent inflammation. Therefore, management of inflammation is always the target of therapy. Sinomenine (SIN) is the prescription drug approved by the Chinese government for RA treatment. A previous study found that SIN was a robust anti-inflammation drug. In this study, we screened the different secretory cytokines using inflammation antibody arrays and qRT-PCR in both LPS-induced and SIN-treated RAW264.7 cells followed by evaluation of the ability of SIN to modulate cytokine secretion in a cell model, collagen-induced arthritis (CIA) mouse model, and RA patients. Several clinical indexes affecting the 28-joint disease activity score (DAS28) were determined before and after SIN treatment. Clinical indexes, inflammatory cytokine secretion, and DAS28 were compared among RA patients treated with either SIN or methotrexate (MTX). To explore the mechanism of SIN anti-inflammatory function, RA-associated monocyte/macrophage subsets were determined using flow cytometry in CIA mouse model and RA patients, both treated with SIN. The results demonstrated that SIN regulated IL-6, GM-CSF, IL-12 p40, IL-1α, TNF-α, IL-1β, KC (CXCL1), Eotaxin-2, IL-10, M-CSF, RANTES, and MCP-1 secretion and and reduced RA activity and DAS28 in a clinical setting. Furthermore, SIN attenuated CD11bF4/80CD64 resident macrophages in the synovial tissue, CD11bLy6CCD43 macrophages in the spleen and draining lymph nodes of CIA mice. The percentage of CD14CD16 peripheral blood mononuclear cells was reduced by SIN in RA patients. These data indicated that SIN regulates the secretion of multiple inflammatory cytokines and monocyte/macrophage subsets, thereby suppressing RA progression. Therefore, along with MTX, SIN could be an alternative cost-effective anti-inflammatory agent for treating RA.
Topics: Adult; Aged; Animals; Antirheumatic Agents; Arthritis, Experimental; Arthritis, Rheumatoid; Collagen; Cytokines; Diclofenac; Disease Progression; Drug Therapy, Combination; Drugs, Chinese Herbal; Female; Humans; Inflammation Mediators; Macrophages; Male; Methotrexate; Mice; Mice, Inbred DBA; Middle Aged; Monocytes; Morphinans; RAW 264.7 Cells; Severity of Illness Index; Synovial Membrane; Treatment Outcome
PubMed: 30319663
DOI: 10.3389/fimmu.2018.02228 -
Nature Jan 2023Mu-opioid receptor (µOR) agonists such as fentanyl have long been used for pain management, but are considered a major public health concern owing to their adverse side...
Mu-opioid receptor (µOR) agonists such as fentanyl have long been used for pain management, but are considered a major public health concern owing to their adverse side effects, including lethal overdose. Here, in an effort to design safer therapeutic agents, we report an approach targeting a conserved sodium ion-binding site found in µOR and many other class A G-protein-coupled receptors with bitopic fentanyl derivatives that are functionalized via a linker with a positively charged guanidino group. Cryo-electron microscopy structures of the most potent bitopic ligands in complex with µOR highlight the key interactions between the guanidine of the ligands and the key Asp residue in the Na site. Two bitopics (C5 and C6 guano) maintain nanomolar potency and high efficacy at G subtypes and show strongly reduced arrestin recruitment-one (C6 guano) also shows the lowest G efficacy among the panel of µOR agonists, including partial and biased morphinan and fentanyl analogues. In mice, C6 guano displayed µOR-dependent antinociception with attenuated adverse effects, supporting the µOR sodium ion-binding site as a potential target for the design of safer analgesics. In general, our study suggests that bitopic ligands that engage the sodium ion-binding pocket in class A G-protein-coupled receptors can be designed to control their efficacy and functional selectivity profiles for G, G and G subtypes and arrestins, thus modulating their in vivo pharmacology.
Topics: Animals; Mice; Analgesics, Opioid; Arrestins; Cryoelectron Microscopy; Fentanyl; Ligands; Morphinans; Receptors, Opioid, mu; Binding Sites; Nociception; Drug Design
PubMed: 36450356
DOI: 10.1038/s41586-022-05588-y -
Clinical Journal of the American... Dec 2017Uremic pruritus in patients on hemodialysis is associated with depression, lower quality of life, and mortality. We studied the prevalence, awareness, and treatment of... (Comparative Study)
Comparative Study
BACKGROUND AND OBJECTIVES
Uremic pruritus in patients on hemodialysis is associated with depression, lower quality of life, and mortality. We studied the prevalence, awareness, and treatment of pruritus to assess how well this important condition is currently managed internationally.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS
Data from 35,452 patients on hemodialysis in up to 17 countries from the Dialysis Outcomes and Practice Patterns Study were analyzed to describe pruritus prevalence from 1996 to 2015. Data from 6256 patients and 268 medical directors in 17 countries in 2012-2015 were analyzed to describe predictors, effects, medical directors' awareness, and treatment of pruritus.
RESULTS
Patients very much or extremely bothered by itching declined from 28% in 1996 to 18% in 2015. In 2012-2015, among patients nearly always or always bothered by itching, pruritus had a major effect on work and social life; 18% used no treatment for pruritus, and 17% did not report itching to health care staff. In total, 69% of medical directors underestimated the prevalence of pruritus in their unit. Managing high serum phosphorus and low Kt/V was ranked as the most important intervention, but no relationship was found between these factors and pruritus; 57% of medical directors used oral antihistamines for first-line chronic treatment of pruritus. Gabapentin was used by 45% as first-, second-, or third-line treatment. Nalfurafine was only used in Japan.
CONCLUSIONS
The prevalence of pruritus in people on hemodialysis is decreasing but remains underestimated. Large numbers of patients on hemodialysis with severe pruritus do not receive treatment. There is wide variation in the use of unlicensed medications for the treatment of pruritus. These data provide a benchmark for initiatives to improve the management of uremic pruritus.
MULTIMEDIA
This article contains multimedia at https://vimeo.com/49458473This article contains multimedia at vimeo.com/49455976.
Topics: Aged; Aged, 80 and over; Amines; Antipruritics; Chronic Disease; Cyclohexanecarboxylic Acids; Female; Gabapentin; Health Knowledge, Attitudes, Practice; Histamine Antagonists; Humans; Hyperphosphatemia; Internationality; Male; Middle Aged; Morphinans; Nephrology; Practice Patterns, Physicians'; Prevalence; Pruritus; Renal Dialysis; Risk Factors; Spiro Compounds; Surveys and Questionnaires; Uremia; gamma-Aminobutyric Acid
PubMed: 28923831
DOI: 10.2215/CJN.03280317 -
British Journal of Anaesthesia Oct 2019
Topics: Humans; Naloxone
PubMed: 31420087
DOI: 10.1016/j.bja.2019.07.007 -
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