The Effect of Opiates on Bone Formation and Bone Healing

Drug-induced osteoporosis and mechanisms of bone tissue regeneration through trace elements

Osteoporosis is associated with an imbalance in bone formation, with certain drugs used in disease treatment being implicated in its development. Supplementation with trace elements may contribute to bone regeneration, offering an alternative approach by enhancing bone mineral density (BMD) and thereby thwarting the onset of osteoporosis. This review aims to assess the mechanisms through which trace elements such as copper (Cu), iron (Fe), selenium (Se), manganese (Mn), and zinc (Zn) are linked to increased bone mass, thus mitigating the effects of pharmaceuticals. Our findings underscore that the use of drugs such as aromatase inhibitors (AIs), proton pump inhibitors (PPIs), antiretrovirals, glucocorticoids, opioids, or anticonvulsants can result in decreased BMD, a primary contributor to osteoporosis. Research indicates that essential elements like Cu, Fe, Se, Mn, and Zn, through various mechanisms, can bolster BMD and forestall the onset of the disease, owing to their protective effects. Consequently, our study recommends a minimum daily intake of these essential minerals for patients undergoing treatment with the aforementioned drugs, as the diverse mechanisms governing the effects of trace elements Cu, Fe, Mn, Se, and Zn facilitate bone remodeling.

Protective effect of dexmedetomidine against delayed bone healing caused by morphine via PI3K/Akt mediated Nrf2 antioxidant defense system

Background

As a class of analgesics, opioids are frequently used to treat both acute and chronic moderate to severe pain. Patients frequently receive opioid painkillers after orthopedic accidents or surgeries. Evidence suggests that opioid drug users have a 55.1% higher risk of fracture and poor bone repair than non-users of opioid drugs. The key pathogenic alterations in the incidence and progression of poor bone repair are over apoptosis and aging of osteoblasts due to the stress caused by oxidation. Dexmedetomidine (Dex) has been proven to protect against a variety of degenerative illnesses by reducing oxidative stress. However, nothing is known about how it affects bone repair.

Methods

PI3K/Akt/Nrf2 pathway was detected by immunofluorescence and Western blot. SOD, CAT, JC-1, dihydroethidium and mitosox were used in the Oxidative Stress. Micro-CT, H&E and Masson's staining, immunohistochemically were performed to evaluate the therapeutic effects of DEX on calvarial defects in the morphine-induced rat model.

Results

We found that morphine-induced an imbalance in the metabolism and catabolism of primary rat Osteoblasts. However, these conditions could be inhibited by DEX treatment. In the meantime, DEX induced the expression of Nrf2-regulated antioxidant enzymes such as NQO1, HO-1, GCLm, GCLc, and TrxR1. DEX-mediated Nrf2 activation is linked to the PI3K/Akt signaling system. Furthermore, it has been established that intravenous DEX enhanced the growth of bone healing in a model of a surgically produced rat cranial lesion.

Conclusion

This is the first description of the unique DEX mechanism acting as a Nrf2 activator against morphine-mediated oxidative harm, raising the possibility that the substance may be used to prevent bone defects.

Problems with opioids beyond misuse

The U.S. is grappling with an opioid epidemic, with millions of adults on long-term opioid therapy (LTOT). Although patients often report pain relief and improved daily function with opioids, research shows no significant differences in short-term outcomes between opioid and non-opioid users, as well as no long-term opioid benefits. This scoping review aims to identify lesser-known side effects of long-term opioid use and increase awareness of them, allowing healthcare providers and patients to better assess the risks and benefits of opioid use. Our data search from PubMed and Google Scholar used keywords related to opioids, chronic pain, hypogonadism, endocrinopathies, cancer progression, cardiovascular events, renovascular events, sleep disturbances, mood disorders and others, narrowing down to English-language full articles published from January 2018 to April 2023. This review emphasizes the probable serious adverse consequences of long-term opioid use on various body systems in patients with chronic pain. Given the lack of long-term benefits and significant adverse effects, our review underscores the critical need for healthcare providers to include these risks in discussions with patients when considering the long-term use of opioid therapy.

Longitudinal Assessment of Bone Mineral Density in Women Living With and Without HIV Across Reproductive Phases

BACKGROUND

Women living with HIV commonly experience low areal bone mineral density (BMD), but whether this is affected by low ovarian hormonal states (prolonged amenorrhea or menopause) is unknown. We compared rates of BMD loss between women living with HIV and HIV-negative control women and investigated its association with low ovarian hormonal states.

SETTING

Women living with HIV were enrolled from Vancouver Canada and controls from 9 Canadian sites.

METHODS

This longitudinal analysis included age-matched women living with HIV in the Children and Women: AntiRetrovirals and Markers of Aging cohort and controls in the population-based Canadian Multicentre Osteoporosis Study. Rate of change/year in BMD at the total hip and lumbar spine (L1-L4) between 3 and 5 years was compared between groups, adjusting for sociodemographic and clinical variables.

RESULTS

Ninety-two women living with HIV (median [interquartile range] age: 49.5 [41.6-54.1] years and body mass index: 24.1 [20.7-30.8] kg/m 2 ) and 278 controls (age: 49.0 [43.0-55.0] years and body mass index: 25.8 [22.9-30.6] kg/m 2 ) were included. Total hip BMD loss was associated with HIV (β: -0.003 [95% CI: -0.006 to -0.0001] g/cm 2 /yr), menopause (β: -0.007 [-0.01 to -0.005] g/cm 2 /yr), and smoking (β: -0.003 [-0.006 to -0.0002] g/cm 2 /yr); BMD gain was linked with higher body mass index (β: 0.0002 [0.0007-0.0004] g/cm 2 /yr). Menopause was associated with losing L1-L4 BMD (β: -0.01 [-0.01 to -0.006] g/cm 2 /yr). Amenorrhea was not associated with BMD loss.

CONCLUSIONS

HIV and menopause negatively influenced total hip BMD. These data suggest women living with HIV require hip BMD monitoring as they age.

To Be Frail or Not to Be Frail: This Is the Question-A Critical Narrative Review of Frailty

Many factors have contributed to rendering frailty an emerging, relevant, and very popular concept. First, many pandemics that have affected humanity in history, including COVID-19, most recently, have had more severe effects on frail people compared to non-frail ones. Second, the increase in human life expectancy observed in many developed countries, including Italy has led to a rise in the percentage of the older population that is more likely to be frail, which is why frailty is much a more common concern among geriatricians compared to other the various health-care professionals. Third, the stratification of people according to the occurrence and the degree of frailty allows healthcare decision makers to adequately plan for the allocation of available human professional and economic resources. Since frailty is considered to be fully preventable, there are relevant consequences in terms of potential benefits both in terms of the clinical outcome and healthcare costs. Frailty is becoming a popular, pervasive, and almost omnipresent concept in many different contexts, including clinical medicine, physical health, lifestyle behavior, mental health, health policy, and socio-economic planning sciences. The emergence of the new "science of frailty" has been recently acknowledged. However, there is still debate on the exact definition of frailty, the pathogenic mechanisms involved, the most appropriate method to assess frailty, and consequently, who should be considered frail. This narrative review aims to analyze frailty from many different aspects and points of view, with a special focus on the proposed pathogenic mechanisms, the various factors that have been considered in the assessment of frailty, and the emerging role of biomarkers in the early recognition of frailty, particularly on the role of mitochondria. According to the extensive literature on this topic, it is clear that frailty is a very complex syndrome, involving many different domains and affecting multiple physiological systems. Therefore, its management should be directed towards a comprehensive and multifaceted holistic approach and a personalized intervention strategy to slow down its progression or even to completely reverse the course of this condition.

Comparing the efficacy of intravenous morphine versus ibuprofen or the combination of ibuprofen and acetaminophen in patients with closed limb fractures: a randomized clinical trial

INTRODUCTION

This study aims to investigate the effectiveness of intravenous ibuprofen or intravenous ibuprofen plus acetaminophen compared to intravenous morphine in patients with closed extremity fractures.

METHODS

A triple-blinded randomized clinical trial was conducted at a tertiary trauma center in Iran. Adult patients between 15 and 60 years old with closed, isolated limb fractures and a pain intensity of at least 6/10 on the visual analog scale (VAS) were eligible. Patients with specific conditions or contraindications were not included. Participants were randomly assigned to receive intravenous ibuprofen, intravenous ibuprofen plus acetaminophen, or intravenous morphine. Pain scores were assessed using the visual analog scale at baseline and 5, 15, 30, and 60 min after drug administration. The primary outcome measure was the pain score reduction after one hour.

RESULTS

Out of 388 trauma patients screened, 158 were included in the analysis. There were no significant differences in age or sex distribution among the three groups. The pain scores decreased significantly in all groups after 5 min, with the morphine group showing the lowest pain score at 15 min. The maximum effect of ibuprofen was observed after 30 min, while the ibuprofen-acetaminophen combination maintained its effect after 60 min. One hour after injection, pain score reduction in the ibuprofen-acetaminophen group was significantly more than in the other two groups, and pain score reduction in the ibuprofen group was significantly more than in the morphine group.

CONCLUSION

The study findings suggest that ibuprofen and its combination with acetaminophen have similar or better analgesic effects compared to morphine in patients with closed extremity fractures. Although morphine initially provided the greatest pain relief, its effect diminished over time. In contrast, ibuprofen and the ibuprofen-acetaminophen combination maintained their analgesic effects for a longer duration. The combination therapy demonstrated the most sustained pain reduction. The study highlights the potential of non-opioid analgesics in fracture pain management and emphasizes the importance of initiation of these medications as first line analgesic for patients with fractures. These findings support the growing trend of exploring non-opioid analgesics in pain management.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05630222 (Tue, Nov 29, 2022). The manuscript adheres to CONSORT guidelines.

Tuberous sclerosis complex 1 targeted depletion in macrophages promotes osteogenesis by modulating secretion of Oncostatin M in the inflammatory stage of bone healing

In bone healing, earlier bone formation benefits bone repair. The first process of repair following bone injury involves the interaction between macrophage polarization and osteogenic activation of osteoblast linage cells, but the radical difference between the contributions of classically-activated M1 macrophages and alternatively-activated M2 macrophages to osteogenesis remains obscure. To test our hypothesis that M1 macrophages promote bone healing, we generated transgenic mice with myeloid lineage-specific TSC1 deletion (TSC1KO) to investigate the functional roles of M1 macrophages in the process of bone defect healing. We demonstrated that constitutive activation of mammalian target of rapamycin complex 1 (mTORC1) enhances M1 macrophage polarization during bone healing. By creating tibial bone defect as a model of bone repair in TSC1KO mice and their littermates, we surprisingly found osteogenic responses in the defective bone region of TSC1KO mice, where repair occurred by intramembranous ossification (IO) in the mice was promoted due to the enhanced M1-polarized macrophage polarization. We propose that Oncostatin M (OSM) secreted by M1-polarized macrophages but not M2 macrophages likely functions as a paracrine factor in this promoted repair process, as verified by the induction of osteoblastic differentiation and matrix mineralization. Interestingly, the expression level of the OSM receptor (OSMR) was continually upregulated in osteoblast linage cells with M1 medium. Additionally, OSMR activated the signaling transduction system of JAK/STAT/RUNX2 in MSCs, which in turn stimulates the recruitment of osteoblast lineage cells and activates IO. These results indicate that TSC1 targeted depletion in macrophages promotes bone healing by inducing secretion of OSM. This study highlights that regulation of M1 macrophage polarization is a novel basis for the improvement of bone regeneration and that regulation of macrophage polarization can be a potential therapeutic strategy to treat defects in the repair phase of bone healing.

A Closer Look at Opioid-Induced Adrenal Insufficiency: A Narrative Review

Among several opioid-associated endocrinopathies, opioid-associated adrenal insufficiency (OIAI) is both common and not well understood by most clinicians, particularly those outside of endocrine specialization. OIAI is secondary to long-term opioid use and differs from primary adrenal insufficiency. Beyond chronic opioid use, risk factors for OIAI are not well known. OIAI can be diagnosed by a variety of tests, such as the morning cortisol test, but cutoff values are not well established and it is estimated that only about 10% of patients with OIAI will ever be properly diagnosed. This may be dangerous, as OIAI can lead to a potentially life-threatening adrenal crisis. OIAI can be treated and for patients who must continue opioid therapy, it can be clinically managed. OIAI resolves with opioid cessation. Better guidance for diagnosis and treatment is urgently needed, particularly in light of the fact that 5% of the United States population has a prescription for chronic opioid therapy.

Bulleyaconitine A reduces fracture-induced pain and promotes fracture healing in mice

A fracture is a severe trauma that causes dramatic pain. Appropriate fracture pain management not only improves the patient's subjective perception, but also increases compliance with rehabilitation training. However, current analgesics for fracture pain are unsatisfactory because of their negative effects on fracture healing or addiction problems. Bulleyaconitine A (BLA), a non-addictive analgesic medicine, is used for the treatment of chronic pain of musculoskeletal disorders in clinical practice, whereas the effects of BLA on fracture pain is undefined. To evaluate the analgesic effects of BLA on fracture, we generated tibial fracture mice here. It is found that oral administration of BLA to mice alleviates fracture-induced mechanical and thermal hyperalgesia. Interestingly, BLA significantly increases locomotor activity levels and reduces anxiety-like behaviors in fractured mice, as determined by open-field test. Notably, BLA treatment promotes bone mineralization and therefore fracture healing in mice, which may be attributed to the increase in mechanical stimulation caused by exercise. Our study suggests that BLA can be used as a promising analgesic agent for the treatment of fracture pain.

The Impact of P-Glycoprotein on Opioid Analgesics: What's the Real Meaning in Pain Management and Palliative Care?

Opioids are widely used in cancer and non-cancer pain management. However, many transporters at the blood-brain barrier (BBB), such as P-glycoprotein (P-gp, ABCB1/MDR1), may impair their delivery to the brain, thus leading to opioid tolerance. Nonetheless, opioids may regulate P-gp expression, thus altering the transport of other compounds, namely chemotherapeutic agents, resulting in pharmacoresistance. Other kinds of painkillers (e.g., acetaminophen, dexamethasone) and adjuvant drugs used for neuropathic pain may act as P-gp substrates and modulate its expression, thus making pain management challenging. Inflammatory conditions are also believed to upregulate P-gp. The role of P-gp in drug-drug interactions is currently under investigation, since many P-gp substrates may also act as substrates for the cytochrome P450 enzymes, which metabolize a wide range of xenobiotics and endobiotics. Genetic variability of the ABCB1/MDR1 gene may be accountable for inter-individual variation in opioid-induced analgesia. P-gp also plays a role in the management of opioid-induced adverse effects, such as constipation. Peripherally acting mu-opioid receptors antagonists (PAMORAs), such as naloxegol and naldemedine, are substrates of P-gp, which prevent their penetration in the central nervous system. In our review, we explore the interactions between P-gp and opioidergic drugs, with their implications in clinical practice.

Current and Future Therapeutic Options in Pain Management: Multi-mechanistic Opioids Involving Both MOR and NOP Receptor Activation

Opioids are widely used in chronic pain management, despite major concerns about their risk of adverse events, particularly abuse, misuse, and respiratory depression from overdose. Multi-mechanistic opioids, such as tapentadol and buprenorphine, have been widely studied as a valid alternative to traditional opioids for their safer profile. Special interest was focused on the role of the nociceptin opioid peptide (NOP) receptor in terms of analgesia and improved tolerability. Nociceptin opioid peptide receptor agonists were shown to reinforce the antinociceptive effect of mu opioid receptor (MOR) agonists and modulate some of their adverse effects. Therefore, multi-mechanistic opioids involving both MOR and NOP receptor activation became a major field of pharmaceutical and clinical investigations. Buprenorphine was re-discovered in a new perspective, as an atypical analgesic and as a substitution therapy for opioid use disorders; and buprenorphine derivatives have been tested in animal models of nociceptive and neuropathic pain. Similarly, cebranopadol, a full MOR/NOP receptor agonist, has been clinically evaluated for its potent analgesic efficacy and better tolerability profile, compared with traditional opioids. This review overviews pharmacological mechanisms of the NOP receptor system, including its role in pain management and in the development of opioid tolerance. Clinical data on buprenorphine suggest its role as a safer alternative to traditional opioids, particularly in patients with non-cancer pain; while data on cebranopadol still require phase III study results to approve its introduction on the market. Other bifunctional MOR/NOP receptor ligands, such as BU08028, BU10038, and AT-121, are currently under pharmacological investigations and could represent promising analgesic agents for the future.

How Do Drugs Affect the Skeleton? Implications for Forensic Anthropology

Simple Summary

Forensic anthropologists analyze human remains to assist in the identification of the deceased, predominantly by assessing age-at-death, sex, stature, ancestry and any unique identifying features. Whilst methods have been established to create this biological profile of the skeleton, these may be influenced by a number of factors. This paper, for the first time, provides an overview from a reading of the clinical and pharmacological literature to explore whether the intake of drugs can affect the skeleton and whether these may have implications for forensic anthropology casework. In effect, drugs such as tobacco, heroin, and prescription medications can alter bone mineral density, can increase the risk of fractures, destroy bone and changes to the dentition. By considering how drugs can affect the skeleton, forensic anthropologists can be aware of this when attempting to identify the deceased.

Abstract

Forensic anthropologists rely on a number of parameters when analyzing human skeletal remains to assist in the identification of the deceased, predominantly age-at-death, sex, stature, ancestry or population affinity, and any unique identifying features. During the examination of human remains, it is important to be aware that the skeletal features considered when applying anthropological methods may be influenced and modified by a number of factors, and particular to this article, prescription drugs (including medical and non-medical use) and other commonly used drugs. In view of this, this paper aims to review the medical, clinical and pharmacological literature to enable an assessment of those drug groups that as side effects have the potential to have an adverse effect on the skeleton, and explore whether or not they can influence the estimation of age-at-death, sex and other indicators of the biological profile. Moreover, it may be that the observation of certain alterations or inconsistencies in the skeleton may relate to the use of drugs or medication, and this in turn may help narrow down the list of missing persons to which a set of human remains could belong. The information gathered from the clinical and medical literature has been extracted with a forensic anthropological perspective and provides an awareness on how several drugs, such as opioids, cocaine, corticosteroids, non-steroidal anti-inflammatory drugs, alcohol, tobacco and others have notable effects on bone. Through different mechanisms, drugs can alter bone mineral density, causing osteopenia, osteoporosis, increase the risk of fractures, osteonecrosis, and oral changes. Not much has been written on the influence of drugs on the skeleton from the forensic anthropological practitioner perspective; and this review, in spite of its limitations and the requirement of further research, aims to investigate the current knowledge of the possible effects of both prescription and recreational drugs on bones, contributing to providing a better awareness in forensic anthropological practice and assisting in the identification process of the deceased.

The regulative effect and repercussion of probiotics and prebiotics on osteoporosis: involvement of brain-gut-bone axis

Osteoporosis (OP) is a systemic disease characterized by decreased bone mass and degeneration of bone microstructure. In recent years, more and more researches have focused on the close relationship between gut microbiota (GM) and the occurrence and progression of OP, and the regulation of probiotics and prebiotics on bone metabolism has gradually become a research hotspot. Based on the influence of brain-gut-bone axis on bone metabolism, this review expounds the potential mechanisms of probiotics and prebiotics on OP from next perspectives: regulation of intestinal metabolites, regulation of intestinal epithelial barrier function, involvement of neuromodulation, involvement of immune regulation and involvement of endocrine regulation, so as to provide a novel and promising idea for the prevention and treatment of OP in the future.

Exploring the effect of the "quaternary regulation" theory of "peripheral nerve-angiogenesis-osteoclast-osteogenesis" on osteoporosis based on neuropeptides

Osteoporosis is a common bone metabolic disease among the middle-aged and elderly, with its high incidence rate and a major cause of disability and mortality. Early studies found that bone metabolic homeostasis is achieved through osteogenesis-osteoclast coupling. Although current anti-osteoporosis drugs can attenuate bone loss caused by aging, they present specific side effects. With the discovery of CD31^hi Emcn^hi blood vessels in 2014, the effect of H-type blood vessels on bone metabolism has been valued by researchers, and the ternary regulation theory of bone metabolism of "Angiogenesis-Osteoclast-Osteogenesis" has also been recognized. Nowadays, more studies have confirmed that peripheral nerves substantially impact bone metabolism. However, due to the complex function of peripheral nerves, the crosstalk mechanism of "Peripheral nerve-Angiogenesis-Osteoclast-Osteogenesis" has not yet been fully revealed. Neuropeptide serves as signaling molecules secreted by peripheral nerves that regulate blood vessels, osteoblasts, and osteoclasts' functions. It is likely to be the breakthrough point of the quaternary regulation theory of "Peripheral nerve-Angiogenesis-Osteoclast-Osteogenesis". Here, we discuss the effect of peripheral nerves on osteoporosis based on neuropeptides.

Amplification by tramadol of PGD2-induced osteoprotegerin synthesis in osteoblasts: Involvement of μ-opioid receptor and 5-HT transporter

Tramadol, a weak μ-opioid receptor (MOR) agonist with inhibitory effects on the reuptake of serotonin (5-hydroxytryptamine; 5-HT) and norepinephrine, is an effective analgesic to chronic pains. Osteoprotegerin produced by osteoblasts is essential for bone remodeling to suppress osteoclastic bone resorption. We previously reported that prostaglandin D₂ (PGD₂) induces osteoprotegerin synthesis whereby p44/p42 mitogen-activated protein (MAP) kinase, p38 MAP kinase and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) are involved in osteoblast-like MC3T3-E1 cells. Herein, we investigated the mechanism underlying the effect of tramadol on the PGD₂-induced osteoprotegerin synthesis in these cells. Tramadol enhanced the PGD₂-induced release and mRNA expression of osteoprotegerin. Naloxone, a MOR antagonist, reduced the amplification by tramadol of the PGD₂-stimulated osteoprotegerin release. Not the selective norepinephrine reuptake inhibitor reboxetine but the selective serotonin reuptake inhibitors fluvoxamine and sertraline upregulated the PGD₂-induced osteoprotegerin release, which was further amplified by morphine. Tramadol enhanced PGD₂-stimulated phosphorylation of p38 MAP kinase and SAPK/JNK, but not p44/p42 MAP kinase. Both SB203580 and SP600125 suppressed the tramadol effect to enhance the PGD₂-stimulated osteoprotegerin release. Tramadol enhanced the PGE₂-induced osteoprotegerin release as well as PGD₂. These results suggest that tramadol amplifies the PGD₂-induced osteoprotegerin synthesis at the upstream of p38 MAP kinase and SAPK/JNK in the involvement of both MOR and 5-HT transporter in osteoblasts.

Negative pharmacological effect on spine fusion: A narrative review of the literature of evidence-based treatment

Spine fusion surgery is commonly performed for diverse indications, the most frequent one being degenerative spine diseases. Despite the growing importance of this surgery, there is limited evidence concerning the effects of drugs on the process of spine fusion and healing. While asymptomatic sometimes, nonunion of the spine can have tremendous repercussions on the patients' quality of life and the healthcare system rendering it an "expensive complication". This literature review identifies the role of some perioperative drugs in spine fusion and reveals their potential role in pseudarthrosis of the spine. This review also benefits spine surgeons looking for current evidence-based practices. We reviewed the data related to nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, vancomycin, bisphosphonates, proton pump inhibitors (PPIs), pregabalin, and opioids. From the available experimental and clinical studies, we conclude that bisphosphonates might positively influence the process of spine fusion, while steroids and vancomycin have shown variable effects, and the remaining medications likely disturb healing and union of the spine. We recommend spine surgeons be cautious about the drugs they resort to in the critical perioperative period until further clinical studies prove which drugs are safe to be used.

Tissue Regeneration: The Dark Side of Opioids

Opioids are regarded as among the most effective analgesic drugs and their use for the management of pain is considered standard of care. Despite their systematic administration in the peri-operative period, their impact on tissue repair has been studied mainly in the context of scar healing and is only beginning to be documented in the context of true tissue regeneration. Indeed, in mammals, growing evidence shows that opioids direct tissue repair towards scar healing, with a loss of tissue function, instead of the regenerative process that allows for recovery of both the morphology and function of tissue. Here, we review recent studies that highlight how opioids may prevent a regenerative process by silencing nociceptive nerve activity and a powerful anti-inflammatory effect. These data open up new perspectives for inducing tissue regeneration and argue for opioid-restricted strategies for managing pain associated with tissue injury.

Surgery start time and early implant failure: A case-control study

OBJECTIVE

To evaluate the influence of surgery start time (SST) and other patient- and therapy-related variables on the risk for early implant failure (EIF) in an academic setting.

MATERIAL AND METHODS

Data were extracted from the electronic health records of 61 patients who had at least one EIF and 140 age- and gender-matched, randomly selected, non-EIF controls. Bivariate and multivariable analyses were performed to identify relevant associations between EIF and different variables, such as SST.

RESULTS

Incidence of EIF was not significantly associated with SST (HR: 1.9 for afternoon implant placement, 95% CI: 0.9-3.9; p = .105). Other factors that were associated with a significantly increased risk for EIF in a multivariable model were pre-placement ridge augmentation (HR: 7.5, 95% CI: 2.2-25.1; p = .001), intra-operative complications (HR: 5.9, 95% CI: 2.2-16.3; p < .001), simultaneous soft tissue grafting (HR: 5.03, 95% CI: 1.3-19.5; p = .020), simultaneous bone grafting (HR: 3.7, 95% CI: 1.6-8.8; p = .002), and placement with sedation (HR: 3.4, 95% CI: 1.5-7.5; p = .002).

CONCLUSIONS

While SST was not associated with the occurrence of EIF in our cohort, other variables, such as ridge augmentation prior to implant placement, simultaneous bone or soft tissue grafting, intra-operative complications, implant placement with sedation, and number of implants in the oral cavity, were associated with an increased risk for this adverse event.

Factors Associated with Low Bone Density in Opioid Substitution Therapy Patients: A Systematic Review

Background: Long-term opioid therapy is a risk factor for low bone mineral density (BMD). However, other factors may also contribute to low BMD. Several studies have examined the variables that might contribute to low BMD in patients receiving opioid replacement therapy (OST). However, to our knowledge, there was no systemic review conducted to address this particular issue. Thus, we reviewed the articles on the factors associated with low BMD in the population of opioid use disorder receiving substitution therapy. Methods: The articles that examined correlates or risk factors of low BMD in OST population were retrieved from OVID, SCOPUS, and PUBMED from inception until July 2020 by two independent investigators. Results: A total of 429 articles from three databases were retrieved initially. After screening based on eligibility criteria, five articles were included in the final analysis. The risk factors or correlates found to be significantly associated with low BMD in the OST population include male gender, low body mass index, low testosterone level, methadone or heroin use, and longer duration of heavy alcohol use. The review limitations include small sample sizes and inconsistent definition of variables. Conclusion: OST patients should be screened for BMD and its associated factors. Guidelines and training of practitioners involving in the OST service should be provided to increase the detection of low BMD in the OST population.

Safe Use of Opioids in Chronic Kidney Disease and Hemodialysis Patients: Tips and Tricks for Non-Pain Specialists

In patients suffering from moderate-to-severe chronic kidney disease (CKD) or end-stage renal disease (ESRD), subjected to hemodialysis (HD), pain is very common, but often underestimated. Opioids are still the mainstay of severe chronic pain management; however, their prescription in CKD and HD patients is still significantly low and pain is often under-treated. Altered pharmacokinetics and the lack of clinical trials on the use of opioids in patients with renal impairment increase physicians' concerns in this specific population. This narrative review focused on the correct and safe use of opioids in patients with CKD and HD. Morphine and codeine are not recommended, because the accumulation of their metabolites may cause neurotoxic symptoms. Oxycodone and hydromorphone can be safely used, but adequate dosage adjustments are required in CKD. In dialyzed patients, these opioids should be considered as second-line agents and patients should be carefully monitored. According to different studies, buprenorphine and fentanyl could be considered first-line opioids in the management of pain in CKD; however, fentanyl is not appropriate in patients undergoing HD. Tapentadol does not need dosage adjustment in mild-to-moderate renal impairment conditions; however, no data are available on its use in ESRD. Opioid-related side effects may be exacerbated by common comorbidities in CKD patients. Opioid-induced constipation can be managed with peripherally-acting-μ-opioid-receptor-antagonists (PAMORA). Unlike the other PAMORA, naldemedine does not require any dose adjustment in CKD and HD patients. Accurate pain diagnosis, opioid titration and tailoring are mandatory to minimize the risks and to improve the outcome of the analgesic therapy.

Naldemedine: A New Option for OIBD

Opioid-induced bowel dysfunction (OIBD) is a common complication in long-term opioid users and abusers. It is a burdensome condition, which significantly limits quality of life and is associated with increasing health costs. OIBD affects up to 60% of patients with chronic non-cancer pain and over 80% of patients suffering from cancer pain and is one of the conditions of the most common symptoms associated with opioid maintenance. Given the continued use of opioids for chronic pain management in appropriate patients, OIBD is likely to persist in clinical practice in the coming years. We will herein review its underlying pathophysiological mechanisms and the available treatments. In the last years, pharmaceutical research has focused on the opportunity of targeting peripheral mu-opioid receptors without affecting their analgesic activity in the central nervous system, and several peripherally acting mu-opioid receptors antagonists (PAMORAs) drugs have been approved. We will mainly focus on naldemedine, discussing its pharmacological properties, its clinical efficacy and side effects. Head-to-head comparisons between naldemedine and the other PAMORAs are not available yet, but some considerations will be discussed based on the pharmacological and clinical data. As a whole, the available data suggest that naldemedine is a valid treatment option for OIBD, as it is a well-tolerated drug that alleviates constipation without affecting analgesia or causing symptoms of opioid withdrawal.