Novel endomorphin analogues CEMR-1 and CEMR-2 produce potent and long-lasting antinociception with a favourable side effect profile at the spinal level

BACKGROUND AND PURPOSE

Endomorphins have shown great promise as pharmaceutics for the treatment of pain. We have previously confirmed that novel endomorphin analogues CEMR-1 and CEMR-2 behaved as potent μ agonists and displayed potent antinociceptive activities at the supraspinal and peripheral levels. The present study was undertaken to evaluate the antinociceptive properties of CEMR-1 and CEMR-2 following intrathecal (i.t.) administration. Furthermore, their antinociceptive tolerance and opioid-like side effects were also determined.

EXPERIMENTAL APPROACH

The spinal antinociceptive effects of CEMR-1 and CEMR-2 were determined in a series of pain models, including acute radiant heat paw withdrawal test, spared nerve injury-induced neuropathic pain, complete Freund's adjuvant-induced inflammatory pain, visceral pain and formalin pain. Antinociceptive tolerance was evaluated in radiant heat paw withdrawal test.

KEY RESULTS

Spinal administration of CEMR-1 and CEMR-2 produced potent and prolonged antinociceptive effects in acute pain. CEMR-1 and CEMR-2 may produce their antinociception through distinct μ receptor subtypes. These two analogues also exhibited significant analgesic activities in neuropathic, inflammatory, visceral and formalin pain at the spinal level. It is noteworthy that CEMR-1 showed non-tolerance-forming analgesic properties, while CEMR-2 exhibited substantially reduced antinociceptive tolerance. Furthermore, both analogues displayed no or reduced side effects on conditioned place preference response, physical dependence, locomotor activity and gastrointestinal transit.

CONCLUSIONS AND IMPLICATIONS

The present investigation demonstrated that CEMR-1 and CEMR-2 displayed potent and long-lasting antinociception with a favourable side effect profile at the spinal level. Therefore, CEMR-1 and CEMR-2 might serve as promising analgesic compounds with minimal opioid-like side effects.

Risk factors for medication-related short-term readmissions in adults - a scoping review

BACKGROUND

Hospital readmissions due to medication-related problems occur frequently, burdening patients and caregivers emotionally and straining health care systems economically. In times of limited health care resources, interventions to mitigate the risk of medication-related readmissions should be prioritized to patients most likely to benefit. Focusing on general internal medicine patients, this scoping review aims to identify risk factors associated with drug-related 30-day hospital readmissions.

METHODS

We began by searching the Medline, Embase, and CINAHL databases from their inception dates to May 17, 2022 for studies reporting risk factors for 30-day drug-related readmissions. We included all peer-reviewed studies, while excluding literature reviews, conference abstracts, proceeding papers, editorials, and expert opinions. We also conducted backward citation searches of the included articles. Within the final sample, we analyzed the types and frequencies of risk factors mentioned.

RESULTS

After deduplication of the initial search results, 1159 titles and abstracts were screened for full-text adjudication. We read 101 full articles, of which we included 37. Thirteen more were collected via backward citation searches, resulting in a final sample of 50 articles. We identified five risk factor categories: (1) patient characteristics, (2) medication groups, (3) medication therapy problems, (4) adverse drug reactions, and (5) readmission diagnoses. The most commonly mentioned risk factors were polypharmacy, prescribing problems-especially underprescribing and suboptimal drug selection-and adherence issues. Medication groups associated with the highest risk of 30-day readmissions (mostly following adverse drug reactions) were antithrombotic agents, insulin, opioid analgesics, and diuretics. Preventable medication-related readmissions most often reflected prescribing problems and/or adherence issues.

CONCLUSIONS

This study's findings will help care teams prioritize patients for interventions to reduce medication-related hospital readmissions, which should increase patient safety. Further research is needed to analyze surrogate social parameters for the most common drug-related factors and their predictive value regarding medication-related readmissions.

Case report: The lesson from opioid withdrawal symptoms mimicking paraganglioma recurrence during opioid deprescribing in cancer pain

Pain is one of the predominant and troublesome symptoms that burden cancer patients during their whole disease trajectory: adequate pain management is a fundamental component of cancer care. Opioid are the cornerstone of cancer pain relief therapy and their skillful management must be owned by physicians approaching cancer pain patients. In light of the increased survival of cancer patients due to advances in therapy, deprescription should be considered as a part of the opioid prescribing regime, from therapy initiation, dose titration, and changing or adding drugs, to switching or ceasing. In clinical practice, opioid tapering after pain remission could be challenging due to withdrawal symptoms' onset. Animal models and observations in patients with opioid addiction suggested that somatic and motivational symptoms accompanying opioid withdrawal are secondary to the activation of stress-related process (mainly cortisol and catecholamines mediated). In this narrative review, we highlight how the lack of validated guidelines and tools for cancer patients can lead to a lower diagnostic awareness of opioid-related disorders, increasing the risk of developing withdrawal symptoms. We also described an experience-based approach to opioid withdrawal, starting from a case-report of a symptomatic patient with a history of metastatic pheochromocytoma-paraganglioma.

General anesthesia combined with bilateral 2-level erector spinae plane block may accelerate postoperative gastrointestinal function recovery and rehabilitation process in patients undergoing posterior lumbar surgery: A randomized controlled trial

BACKGROUND

This randomized controlled trial explored whether bilateral 2-level erector spinae plane block could accelerate postoperative gastrointestinal function and rehabilitation in patients undergoing posterior lumbar surgery.

METHODS

A total of 80 adult patients undergoing posterior lumbar surgery between March 2021 and August 2021 were randomized to either ultrasound-guided bilateral 2-level erector spinae plane block (group E) or not (group C). General anesthesia was routinely performed. The primary outcome was the time of the first flatus after surgery. We also recorded the first food and liquid intake, first off-bed activity, days of hospital stay, and postoperative complications. Postoperative visual analog scale score and opioid consumption were also recorded. A venous blood sample was taken to measure the serum concentration of lipopolysaccharides, c-reactive protein, tumor necrosis factor-alpha, interleukin-6, and blood glucose before induction of anesthesia, immediately after, and 24 and 48 hours after surgery.

RESULTS

Seventy-seven patients, 39 in group C and 38 in group E, finished the trial. Patients in group E had a significantly shorter time to first flatus (16.2 ± 3.2 vs 19.7 ± 3.0 hours, P < .05), earlier liquid intake (1.7 ± 0.2 vs 1.9 ± 0.3 hours, P < .05), earlier food intake (1.9 ± 0.2 vs 2.1 ± 0.3 hours, P < .05), and first off-bed activity (27.9 ± 3.2 vs 31.4 ± 3.3 h, P < .05). Patients in group E had shorter postoperative hospital stay (4.6 [4.2-5.5] d vs 5.4 [4.5-6.3], P < .05). We found that patients in group E had less pain and total sufentanil consumption (129 [120-133] vs 138 [132-147] μg, P < .05) within 24 hours after surgery. At 24 hours after surgery, the serum concentrations of lipopolysaccharides, tumor necrosis factor-alpha, interleukin-6, and C-reactive protein in group E were significantly decreased compared to group C (P < .05).

CONCLUSION

Bilateral 2-level erector spinae plane block can accelerate gastrointestinal function recovery and shorten the length of hospital stay in patients undergoing open posterior lumbar surgery. The potential mechanism may attribute to the opioids-sparing effects and anti-stress-related anti-inflammatory effects of bilateral 2-level erector spinae plane block.

Prevalence, Recognition, and Risk Factors of Constipation among Medically Hospitalized Patients: A Cohort Prospective Study

Background and Objective: Constipation is a prevalent gastrointestinal condition that has a substantial impact on individuals and healthcare systems. This condition adversely affects health-related quality of life and leads to escalated healthcare expenses due to an increase in office visits, referrals to specialists, and hospital admission. This study aimed to evaluate the prevalence, recognition, risk factors, and course of constipation among hospitalized patients in medical wards. Materials and Methods: A prospective study was conducted, including all adult patients admitted to the General Medicine Unit between 1 February 2022 and 31 August 2022. Constipation was identified using the Constipation Assessment Scale (CAS), and relevant factors were extracted from the patients' medical records. Results: Among the patients who met the inclusion criteria (n = 556), the prevalence of constipation was determined to be 55.6% (95% CI 52.8-58.4). Patients with constipation were found to be older (p < 0.01) and had higher frailty scores (p < 0.01). Logistic regression analysis revealed that heart failure (Odds ratio (OR) 2.1; 95% CI 1.2-3.7; p = 0.01), frailty score (OR 1.4; 95% CI 1.2-1.5; p < 0.01), and dihydropyridines calcium channel blockers (OR 1.8; 95% CI 1.2-2.8; p < 0.01) were independent risk factors for constipation. Furthermore, the medical team did not identify constipation in 217 patients (64.01%). Conclusions: Constipation is highly prevalent among medically hospitalized patients. To ensure timely recognition and treatment, it is essential to incorporate a daily constipation assessment scale into each patient's medical records.

Gangrenous cholecystitis during extracorporeal membrane oxygenation operation: A case report and literature review

A 50-year-old male presented to the emergency department of a hospital with an acute myocardial infarction who underwent cardiopulmonary resuscitation (CPR) followed by extracorporeal membrane oxygenation (ECMO). The patient developed persistent jaundice during the course of the disease, which was later found to be gangrenous cholecystitis. We believe this case report will alert clinicians to the possibility of this complication and encourage early detection and intervention to improve the prognosis. Traditionally, the gallbladder has received secondary attention in patients receiving ECMO support, as vital organs tend to be prioritized. However, this case report illustrates the importance of preserving gallbladder function in patients receiving ECMO support.

Perioperative Management in the Collegiate Athlete: An Integrated Approach

Collegiate athletes face rigorous physical, academic, and emotional demands. While significant attention has been paid to injury prevention among young athletes in the past two decades, orthopedic injury rates remain high among collegiate athletes, and a significant number will undergo surgical management for injuries each year. In this narrative review, we describe techniques for perioperative management of pain and stress after surgery in collegiate athletes. In particular, we outline pharmacologic and non-pharmacologic management of surgical pain, with a goal of minimizing opiate consumption. We emphasize a multi-disciplinary approach to optimizing post-operative recovery in collegiate athletes help minimize reliance on opiate pain medication. Additionally, we recommend that institutional resources should be harnessed to support athletes in their well-being, from a nutritional, psychological and sleep standpoint. Critical to success in perioperative pain management is the communication among the athletic medicine team members and with the athlete and family to address pain and stress management and encourage timely, safe return to play.

The Effect of Nursing Management of Patients Undergoing Interventional Therapy for Liver Cancer Compared with Standard Care on Patient-Reported Outcomes

BACKGROUND

To investigate the efficacy of individualized symptom management based on patients' self-reports during interventional therapy (IT) for liver cancer.

METHODS

Patients with liver cancer who received IT at First Affiliated Hospital of ****** University from April to August 2019 were apportioned to either an intervention or control group (n = 70 each). The control group received routine nursing care and the intervention group received a nursing management program. The severity of specific symptoms, as measured by the Karnofsky Performance Scale (KPS), and satisfaction with nursing care, were analyzed.

RESULTS

Compared to the control group, patients given individualized management experienced significantly less severe pain, nausea, anxiety, and fatigue (p < .05). The scores for KPS and satisfaction with care were both significantly improved in the intervention group than in the control group (p < .05).

CONCLUSION

This high-quality nursing management program predicated on patients' self-reports is worthy of clinical application and popular adoption.

Reducing Opioid-Induced Constipation Post-Cardiac Surgery: An Improvement Project in a Pediatric Cardiac Intensive Care Unit

BACKGROUND

Pain management with opioids and underutilization of prophylaxis for constipation can prolong a patient's hospital length of stay and impede pain management efforts.

PROBLEM

In pediatric postoperative cardiac patients, opioid therapy is a common approach to pain management but often places them at greater risk for constipation due to anatomy and age.

METHODS

A retrospective review of 50 patients' medical records for baseline data was conducted, and a survey evaluated providers' current knowledge and practice.

INTERVENTIONS

The intervention was an electronic order set that provided decision support. Additionally, prophylactic measures were supported by a validated assessment tool that created a common language to report constipation risk.

RESULTS

Although not statistically significant, postintervention data demonstrated a 21.5% decrease in postoperative constipation and a 57% increase in ordered bowel regimens.

CONCLUSION

More focus is needed toward prophylactic bowel regimens to reduce the risk in this already high-risk population.

Opioid Analgesia and Opioid-Induced Adverse Effects: A Review

Opioids are widely used as therapeutic agents against moderate to severe acute and chronic pain. Still, these classes of analgesic drugs have many potential limitations as they induce analgesic tolerance, addiction and numerous behavioural adverse effects that often result in patient non-compliance. As opium and opioids have been traditionally used as painkillers, the exact mechanisms of their adverse reactions over repeated use are multifactorial and not fully understood. Older adults suffer from cancer and non-cancer chronic pain more than younger adults, due to the physiological changes related to ageing and their reduced metabolic capabilities and thus show an increased number of adverse reactions to opioid drugs. All clinically used opioids are μ-opioid receptor agonists, and the major adverse effects are directly or potentially connected to this receptor. Multifunctional opioid ligands or peripherally restricted opioids may elicit fewer adverse effects, as shown in preclinical studies, but these results need reproducibility from further extensive clinical trials. The current review aims to overview various mechanisms involved in the adverse effects induced by opioids, to provide a better understanding of the underlying pathophysiology and, ultimately, to help develop an effective therapeutic strategy to better manage pain.

Acupuncture Relieves Opioid-Induced Constipation in Clinical Cancer Therapy - A Meta-Analysis and Systematic Review

Cancer pain is a common problem in clinical cancer therapy. Opioid analgesia is one of the most effective drugs for pain relief with satisfying performance besides the side effect of opioid-induced constipation (OIC). Acupuncture, as a Chinese traditional non-invasive intervention, has been applied to clinical cancer pain management and functional constipation therapy. However, only a few studies have adopted this treatment for OIC patients. Due to limited numbers of investigated subjects and variability of application methods, including treatment apparatus, acupoints, durations, and sessions, the interpretation of acupuncture’s therapy effects from single-site randomized clinical trials (RCT) is limited. Therefore, we conducted a meta-analysis by collecting published data from Pubmed, Embase, Cochrane library, and Web of Science. Five RCTs focusing on the application of acupuncture with or without medication in OIC patients were included. An overall remission rate of 86.8% in the acupuncture-treated group was achieved, higher than the control group (78.9%; RR, 1.10, 95% CI [1.03, 1.18]). The symptom scores, reporting on defecation frequency, defecation straining, abdominal pain, defection time, and stool property, in acupuncture groups were lower than control groups with a standardized mean difference (SMD) of −2.21 [−4.15, −0.27]. The quality of life (QOL) for patients in the acupuncture treated group increased compared to the control group with reduced PAC-QOL scores (SMD, −1.02 [−1.78, −0.26]). Referring to the effects from pure acupuncture treatment (SMD, −0.43 [−0.83, −0.03]), the co-intervention of acupuncture and drugs (SMD, −1.77 [−2.51, −1.02]) improved the life quality of patients more remarkably (P < 0.05). Overall, our data confirmed the therapeutic effects of acupuncture in the treatment of OIC. The co-intervention of acupuncture with drugs improves the outcomes of OIC patients better than a single strategy. Combined therapy with both medicine and acupuncture has insightful potential for future clinical cancer patient management on constipation problems.

Management of Opioid-Induced Constipation and Bowel Dysfunction: Expert Opinion of an Italian Multidisciplinary Panel

The prescribing and use of opioid analgesics is increasing in Italy owing to a profusion in the number and types of opioid analgesic products available, and the increasing prevalence of conditions associated with severe pain, the latter being related to population aging. Herein we provide the expert opinion of an Italian multidisciplinary panel on the management of opioid-induced constipation (OIC) and bowel dysfunction. OIC and opioid-induced bowel dysfunction are well-recognised unwanted effects of treatment with opioid analgesics that can profoundly affect quality of life. OIC can be due to additional factors such as reduced mobility, a low-fibre diet, comorbidities, and concomitant medications. Fixed-dose combinations of opioids with mu (μ) opioid receptor antagonists, such as oxycodone/naloxone, have become available, but have limited utility in clinical practice because the individual components cannot be independently titrated, creating a risk of breakthrough pain as the dose is increased. A comprehensive prevention and management strategy for OIC should include interventions that aim to improve fibre and fluid intake, increase mobility or exercise, and restore bowel function without compromising pain control. Recommended first-line pharmacological treatment of OIC is with an osmotic laxative (preferably polyethylene glycol [macrogol]), or a stimulant laxative such as an anthraquinone. A second laxative with a complementary mechanism of action should be added in the event of an inadequate response. Second-line treatment with a peripherally acting μ opioid receptor antagonist (PAMORA), such as methylnaltrexone, naloxegol or naldemedine, should be considered in patients with OIC that has not responded to combination laxative treatment. Prokinetics or intestinal secretagogues, such as lubiprostone, may be appropriate in the third-line setting, but their use in OIC is off-label in Italy, and should therefore be restricted to settings such as specialist centres and clinical trials.

Discovery, Structure-Activity Relationship, and Mechanistic Studies of 1-((3R,4S)-3-((Dimethylamino)methyl)-4-hydroxy-4-(3-methoxyphenyl)piperidin-1-yl)-2-(2,4,5-trifluorophenyl)ethan-1-one as a Novel Potent Analgesic

Management of moderate to severe pain relies heavily on opioid analgesics such as morphine, oxycodone, and fentanyl in clinics. However, their prolonged use was associated with undesirable side effects. Many new strategies to reduce side effects have been proposed, but not without disadvantages. Using a hot plate model as a phenotypic screening method, our studies identified (3R,4S)-9d with a new scaffold as a potent analgesic with ED₅₀ values of 0.54 mg/kg and 0.021 mg/kg in hot plate and antiwrithing models, respectively. Mechanistic studies showed that it elicited its analgesic effect via the active metabolite (3R,4S)-10a. The mechanism of (3R,4S)-10a-induced activation of the μ opioid receptor (MOR) was proposed by means of molecular dynamics (MD) simulation.

Acupuncture for opioid-induced constipation: Protocol for a systematic review and meta-analysis

BACKGROUND

Opioid-induced constipation (OIC) is one of the most common complications of analgesic therapy for cancer pain patients who suffer moderate to severe pain. Acupuncture as an effective treatment in constipation has been widely applied. But its efficacy has not been assessed systematically. Thus, the purpose of this study is to provide a protocol to explore the efficacy and safety of acupuncture for OIC.

METHODS

Randomized Controlled Trials (RCTs) of acupuncture treatment for OIC in 4 Chinese electronic databases (China National Knowledge Infrastructure, Chinese Biological and Medical Database, China Scientific Journal Database, Wan-Fang Data) and 3 English electronic databases (PubMed, Embase, Cochrane Library) will be searched from their inception to September 31, 2020. RevMan 5.3 software and Stata 14.0 software will be used for meta-analysis, EndNote X9.2 and Cochrane Risk of Bias Tool will be used for literature screening and quality assessment.

RESULTS

This study will present an assessment of the efficacy and safety of acupuncture treatment for OIC patients through summarize high-quality clinical evidence.

CONCLUSION

The conclusion of our systematic review and meta-analysis may provide evidence of whether acupuncture treatment is beneficial to patients with OIC.INPLASY registration number: INPLASY2020100026.

Nonrandomized Clinical Trial of the Effectiveness of a Laxative Treatment Protocol to Time of First Bowel Movement After Uterine Artery Embolization Procedure: A Pilot Study

PURPOSE

The purpose of this pilot study was to determine the efficacy of a proactive laxative protocol for constipation prevention in patients undergoing uterine artery embolization (UAE).

DESIGN

A nonrandomized clinical trial.

METHODS

A nonrandomized trial study design was piloted using a convenience sample of 35 patients undergoing UAE in the course of 1 year.

FINDINGS

There was a statistically significant difference (P < .0001) in time of first bowel movement after UAE when patients followed a proactive laxative protocol. A combination of senna and stool softener taken twice a day for 2 days preoperatively was associated with a shorter time to first bowel movement postoperatively.

CONCLUSIONS

This pilot study supports the benefits of a proactive laxative protocol in helping achieve procedural recovery uncomplicated by constipation in patients undergoing UAE.

Chronic Constipation

Constipation is a common symptom that may be primary (idiopathic or functional) or associated with a number of disorders or medications. Although most constipation is self-managed by patients, 22% seek health care, mostly to primary care physicians (>50%) and gastroenterologists (14%), resulting in large expenditures for diagnostic testing and treatments. There is strong evidence that stimulant and osmotic laxatives, intestinal secretagogues, and peripherally restricted μ-opiate antagonists are effective and safe; the lattermost drugs are a major advance for managing opioid-induced constipation. Constipation that is refractory to available laxatives should be evaluated for defecatory disorders and slow-transit constipation using studies of anorectal function and colonic transit. Defecatory disorders are often responsive to biofeedback therapies, whereas slow-transit constipation may require surgical intervention in selected patients. Both efficacy and cost should guide the choice of treatment for functional constipation and opiate-induced constipation. Currently, no studies have compared inexpensive laxatives with newer drugs that work by other mechanisms.

Pathophysiology and management of opioid-induced constipation: European expert consensus statement

Background

Opioid-induced bowel dysfunction is a complication of opioid therapy, in which constipation is the most common and problematic symptom. However, it is frequently under-recognised and thus effective management is often not instituted despite a number of treatment options.

Objective

The central objective of this study is to provide a summary of the pathophysiology and clinical evaluation of opioid-induced constipation and to provide a pragmatic management algorithm for day-to-day clinical practice.

Methods

This summary and the treatment algorithm is based on the opinion of a European expert panel evaluating current evidence in the literature.

Results

The pathophysiology of opioid-induced constipation is multi-faceted. The key aspect of managing opioid-induced constipation is early recognition. Specific management includes increasing fluid intake, exercise and standard laxatives as well as addressing exacerbating factors. The Bowel Function Index is a useful way of objectively evaluating severity of opioid-induced constipation and monitoring response. Second-line treatments can be considered in those with recalcitrant symptoms, which include gut-restricted or peripherally acting mu-opioid receptor antagonists. However, a combination of interventions may be needed.

Conclusion

Opioid-induced constipation is a common, yet under-recognised and undertreated, complication of opioid therapy. We provide a pragmatic step-wise approach to opioid-induced constipation, which should simplify management for clinicians.

Food pyramid for subjects with chronic pain: foods and dietary constituents as anti-inflammatory and antioxidant agents

Emerging literature suggests that diet constituents may play a modulatory role in chronic pain (CP) through management of inflammation/oxidative stress, resulting in attenuation of pain. We performed a narrative review to evaluate the existing evidence regarding the optimum diet for the management of CP, and we built a food pyramid on this topic. The present review also describes the activities of various natural compounds contained in foods (i.e. phenolic compounds in extra-virgin olive oil (EVO)) listed on our pyramid, which have comparable effects to drug management therapy. This review included 172 eligible studies. The pyramid shows that carbohydrates with low glycaemic index should be consumed every day (three portions), together with fruits and vegetables (five portions), yogurt (125 ml), red wine (125 ml) and EVO; weekly: legumes and fish (four portions); white meat, eggs and fresh cheese (two portions); red or processed meats (once per week); sweets can be consumed occasionally. The food amounts are estimates based on nutritional and practical considerations. At the top of the pyramid there is a pennant: it means that CP subjects may need a specific customised supplementation (vitamin B12, vitamin D, n-3 fatty acids, fibre). The food pyramid proposal will serve to guide dietary intake with to the intent of alleviating pain in CP patients. Moreover, a targeted diet can also help to solve problems related to the drugs used to combat CP, i.e. constipation. However, this paper would be an early hypothetical proposal due to the limitations of the studies.

Parameters Affecting the Enhanced Permeability and Retention Effect: The Need for Patient Selection

The enhanced permeability and retention (EPR) effect constitutes the rationale by which nanotechnologies selectively target drugs to tumors. Despite promising preclinical and clinical results, these technologies have, in our view, underachieved compared to their potential, possibly due to a suboptimal exploitation of the EPR effect. Here, we have systematically analyzed clinical data to identify key parameters affecting the extent of the EPR effect. An analysis of 17 clinical studies showed that the magnitude of the EPR effect was varied and was influenced by tumor type and size. Pancreatic, colon, breast, and stomach cancers showed the highest levels of accumulation of nanomedicines. Tumor size also had an effect on the accumulation of nanomedicines, with large-size tumors having higher accumulation than both medium- and very large-sized tumors. However, medium tumors had the highest percentage of cases (100% of patients) with evidence of the EPR effect. Moreover, tumor perfusion, angiogenesis, inflammation in tumor tissues, and other factors also emerged as additional parameters that might affect the accumulation of nanomedicines into tumors. At the end of the commentary, we propose 2 strategies for identification of suitable patient subpopulations, with respect to the EPR effect, in order to maximize therapeutic outcome.

Mashiningan Improves Opioid-Induced Constipation in Rats by Activating Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel

Opioid receptor stimulants are analgesics used in patients with and without cancer; however, they often cause constipation, resulting in poor adherence and deterioration of the quality of life. Hence, suitable treatments for constipation are required. In this study, we investigated the pharmacological mechanisms of action of mashiningan (MNG), a Kampo medicine used to treat constipation, and evaluated the effect of MNG on opioid-induced constipation in rats. MNG (100 or 300 mg/kg) was orally administered to normal or codeine phosphate (CPH)-induced constipation in rats, and its effect was evaluated on the basis of fecal counts, characteristics, and weight. Small intestinal fluid secretion was measured after treatment with MNG alone or coadministration with a cystic fibrosis transmembrane conductance regulator (CFTR)-specific inhibitor (CFTRinh-172). The effects of MNG on the CFTR and type-2 chloride channel were determined using patch-clamp or short-circuit current experiments, respectively. MNG increased the fecal weight and proportion of soft feces in normal rats. CPH-induced constipation in rats decreased fecal counts and weight, whereas MNG prevented these effects and increased the proportion of soft feces. MNG increased the electronic chloride current, and this effect was inhibited by the CFTRinh-172 in the CFTR assay. Furthermore, MNG increased small intestinal fluid secretion, and this effect was abolished by coadministration with the CFTRinh-172. MNG improved opioid-induced constipation in rats, and this improvement may have been mediated by increasing intestinal fluid secretion via CFTR chloride channel activation. Therefore, MNG is expected as a medicine of the treatment of constipation in patients taking opioids.