Chronic Pain and Chronic Opioid Use After Intensive Care Discharge - Is It Time to Change Practice?

Managing Chronic Pain in Ventilated Critical Care Patients

Pain experienced by mechanically ventilated patients in intensive care units (ICUs) is often overlooked, but it is a significant issue. With over 5 million annual ICU admissions in the United States, the prevalence of pain during hospitalization and its aftermath is a pressing concern. Chronic pain in ICU survivors has been linked to post-traumatic stress disorder, poor quality of life, and long-term impairments known as postintensive care syndrome. Barriers to effective pain management include psychological factors, sedation restrictions, and inadequate use of valid assessment tools.

Using implementation science to decrease variation and high opioid administration in a surgical ICU

BACKGROUND

High doses and prolonged duration of opioids are associated with tolerance, dependence, and increased mortality. Unfortunately, despite recent efforts to curb outpatient opioid prescribing because of the ongoing epidemic, utilization remains high in the intensive care setting, with intubated patients commonly receiving infusions with a potency much higher than doses required to achieve pain control. We attempted to use implementation science techniques to monitor and reduce excessive opioid prescribing in ventilated patients in our surgical intensive care unit (SICU).

METHODS

We conducted a prospective study investigating opioid administration in a closed SICU at an academic medical center over 18 months. Commonly accepted conversions were used to aggregate daily patient opioid use. Patients with a history of chronic opioid use and those being treated with an intracranial pressure monitor/drain, neuromuscular blocker, or extracorporeal membrane oxygenation were excluded. If the patient spent a portion of a day on a ventilator, that day's total was included in the "vent group." morphine milligram equivalents per patient were collected for each patient and assigned to the on-call intensivist. Intensivists were blinded to the data for the first 7 months. They were then provided with academic detailing followed by audit and feedback over the subsequent 11 months, demonstrating how opioid utilization during their time in the SICU compared with the unit average and a blinded list of the other attendings. Student's t tests were performed to compare opioid utilization before and after initiation of academic detailing and audit and feedback.

RESULTS

Opioid utilization in patients on a ventilator decreased by 20.1% during the feedback period, including less variation among all intensivists and a 30.9% reduction by the highest prescribers.

CONCLUSION

Implementation science approaches can effectively reduce variation in opioid prescribing, especially for high outliers in a SICU. These interventions may reduce the risks associated with prolonged use of high-dose opioids.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level II.

Knowledge, attitudes, and perceived barriers regarding pain assessment and management among Thai critical care nurses: A cross-sectional study

BACKGROUND

Pain is a distressing problem which commonly occurs among critically ill patients. Nurses' knowledge of, attitudes, and perceived barriers to pain assessment and management can influence the effectiveness of nursing care.

OBJECTIVE

To explore the current knowledge of, attitudes, and perceived barriers to pain assessment and management among Thai critical care unit nurses.

METHODS

A cross-sectional survey conducted between November 2022 and January 2023 among 158 Thai nurses working in one of eight adult critical care units in a tertiary hospital, evaluated their knowledge of, attitudes, and perceived barriers to pain assessment and management.

RESULTS

Nurses possessed inadequate knowledge and negative attitudes regarding pain assessment and management. The most important barrier to pain assessment and management was "patients are unable to communicate their pain". The results showed a significantly weak positive correlation between nurses' attitudes toward pain assessment and management age (r = 0.26, p = 0.001), year of ICU experience (r = 0.29, p < 0.001), and obtaining a certificate in intensive care nursing (r = 0.37, P < 0.001).

CONCLUSIONS

Thai critical care unit nurses possessed inadequate knowledge and negative attitudes. Further training and education regarding pain assessment and management could include case studies or simulation and immersive virtual reality to improve critical care unit nurses' knowledge and attitudes as well as identifying potential barriers to pain assessment and management in the critical care settings.

IMPLICATIONS FOR CLINICAL PRACTICE

The implications for clinical practice recommend that continued quality assurance procedures should be implemented and maintained to evaluate the effectiveness of current pain assessment practices. Additionally, the perceived barriers to effective pain assessment and management should be considered and managed not only through continued education and training but could include using nursing case review, morbidity and mortality data identifying those patients that experience chronic pain post-ICU discharge.

Meeting complex multidimensional needs in older patients and their families during and beyond critical illness

PURPOSE OF REVIEW

To highlight the emerging crisis of critically ill elderly patients and review the unique burden of multidimensional morbidity faced by these patients and caregivers and potential interventions.

RECENT FINDINGS

Physical, psychological, and cognitive sequelae after critical illness are frequent, durable, and robust across the international ICU outcome literature. Elderly patients are more vulnerable to the multisystem sequelae of critical illness and its treatment and the resultant multidimensional morbidity may be profound, chronic, and significantly affect functional independence, transition to the community, and quality of life for patients and families. Recent data reinforce the importance of baseline functional status, health trajectory, and chronic illness as key determinants of long-term functional disability after ICU. These risks are even more pronounced in older patients.

SUMMARY

The current article is an overview of the outcomes of older survivors of critical illness, putative interventions to mitigate the long-term morbidity of patients, and the consequences for families and caregivers. A multimodal longitudinal approach designed to follow patients for one or more years may foster a better understanding of multidimensional morbidity faced by vulnerable older patients and families and provides a detailed understanding of recovery trajectories in this unique population to optimize outcome, goals of care directives, and ongoing informed consent to ICU treatment.

Prevalence and services for the treatment of chronic pain at residential substance treatment centers

Introduction: Studies suggest that a large proportion of patients with substance use disorders (SUDs) also have underlying chronic pain. There is limited data on prevalence of chronic pain treatment as a component of residential substance use treatment. This initiative sought to investigate the prevalence and type of chronic pain services offered at these residential programs.Methods: This study was a retrospective review of information obtained from residential substance use treatment facility websites contained in SAMHSA's treatment navigator. Nine hundred-fifty out of 2952 websites were randomly selected for analysis. The primary outcome was prevalence of facilities that had chronic pain programs. Services offered were specified as available. Descriptive statistics were used to summarize data.Results: Nine-hundred nine websites (95.7%, [94,97]) were accessible. Twenty-six facilities (2.9%,[1.9,4.2]) had a chronic pain program and of these 22 (84.6%, [64.3,95.0]) specified services offered. Common services included physical therapy (6, 27.3%), massage (12, 54.6%), and acupuncture (10, 45.5%). Of the remaining sites, 630 (69.3%, [66.2,72.3]) specified services offered, including yoga (122, 19.4%) and exercise (199, 31.6%).Conclusion: Our study demonstrated that despite most facilities offering adjunctive services, few had chronic pain programs. This suggests that there is a possible need for better updating of facility websites or possibly an area for improvement in residential substance use treatment settings.

Weighted Blankets for Pain and Anxiety Relief in Acutely Injured Trauma Patients

To determine the impact of a weighted blanket on acute pain and anxiety in trauma patients, a preliminary prospective/retrospective study at a level-one trauma center (n = 24 patients) was conducted. In this study, 12 patients using weighted blankets for five consecutive days were compared to a matched retrospective cohort of 12 patients not using a blanket. The change in morphine milligram equivalents (MME) and alprazolam milligram equivalents (AME) over five days were compared. There was a significant difference of MME per day between the intervention group (mean MME change = -22.9) and matched controls (mean MME change = 6.2; p = 0.0072) by blanket use. Total MMEs in the intervention group decreased by 275.5 and in the control group increased by 75 between day 1 and day 5. There was no significant difference in AME change between groups (p = 0.3227). The majority of patients who took a post-intervention questionnaire reported less pain and less anxiety with blanket use compared to those without blanket use (78% and 56% of patients, respectively). To summarize, trauma patients in acute pain had less opioid use and reported less pain and anxiety when using a weighted blanket for five consecutive days compared to a control group who did not use a blanket.

Pain and psychopathology after intensive care unit admission

Pain and psychopathology are observed in 18% and 55% of patients, respectively, 1 year after intensive care unit (ICU) admission. It is well known that chronic pain and psychopathology have a bidirectional relation in the general population, but it is not known whether this holds true for ICU survivors. The aim of this study was to investigate whether pain before, during and after ICU admission is related to psychopathology in ICU survivors 1 year after discharge. We performed a cohort study in a mixed ICU in the Netherlands between 2013 and 2016. At 1-year follow-up, patients completed the Hospital Anxiety and Depression Scale, the Impact of Event Scale/Impact of Event Scale-Revised, and answered standardised questions regarding pain. Psychopathology was defined as having anxiety, depressive and/or post-traumatic stress disorder symptoms. We used multivariable logistic regression analysis to evaluate the association of pain before, during and after ICU admission with psychopathology at 1 year follow-up. We included 1105 patients of whom 558 (50%) (95% confidence interval (CI) 0.48 to 0.54) had psychopathology at 1 year follow-up. Pain before ICU admission (odds ratio (OR) 1.18; 95% CI 1.10 to 1.26) and pain after ICU admission (OR 2.38; 95% CI 1.68 to 3.35) were associated with psychopathology. Pain during ICU stay was not associated with psychopathology, but the memory of insufficient pain management during ICU stay was (OR 2.19; 95% CI 1.39 to 3.45). Paying attention to pain and pain treatment experiences related to ICU admission may therefore contribute to early identification of ICU survivors at risk of psychopathology development.

Pain Management Strategies in Intensive Care Unit: Challenges and Best Practice

Pain management in the ICU (intensive care unit) is a very complex problem which involves a wide variety of conditions, lack of sufficient tools for use, and high personnel to patient ratio. In the last three decades, pain as a clinical issue has become well analyzed, and treatment protocols based on scientific evidence have been established. Besides medication, some non-pharmacological methods such as music therapy, relaxation, and massage have been proven to be very much practical and manageable in pain management of ICU. The main opioids are utilized predominantly due to their power but NSAIDs and local anesthesia are combined with opioids with the aim to reduce the pain as much as possible. Yet more research now has to prove that pain evaluation and management is effective. This article discusses on the issues and the best approaches to solving them when managing pain in ICU patients.

Characterization of Opioid Use in the Intensive Care Unit and Its Impact Across Care Transitions: A Prospective Study

Purpose: The objective of this study is to characterize opioid intensity in the intensive care unit (ICU) and its association with opioid utilization across care transitions. Methods: This is a prospective cohort study. Medically ill ICU patients with complete medication histories who survived to discharge were included. Opioid intensity was characterized based on IV morphine milligram equivalents (IV MME). Primary outcomes were opioid prescribing upon ICU and hospital discharge. Results: Opioids were prescribed to 34.1% and 31.1% of patients upon ICU and hospital discharge. Within the ≥50 mean IV MME/ICU day cohort, 64.7% of patients received opioids after ICU discharge compared to 45.8% and 13.6% in the 1-49 mean IV MME/ICU day and no opioid groups (P < .05). Within the ≥50 mean IV MME/ICU day cohort, 70.6% of patients were prescribed opioids after hospitalization compared to 37.3% and 13.6% of patients who received less or no opioids. (P < .05). Within the ≥50 mean IV MME/ICU day cohort, 29.4% of patients were opioid naïve and discharged with an opioid, which is over double compared to patients with lower opioid requirements (P < .05). Conclusion: Patients with higher mean daily ICU opioid requirements had increased opioid prescribing across care transitions despite preadmission opioid use.

Long term opioid use after burn injury: a retrospective cohort study

BACKGROUND

Patients who have survive a burn injury might be at risk of opioid dependence after discharge. This study examined the use of opioids in patients who suffer burn injury and explored factors associated with persistent opioid use after hospital discharge.

METHODS

This retrospective cohort study compared adults admitted with a burn injury from 2009 to 2019 with two matched comparison cohorts from the general population and adults with a diagnosis of acute pancreatitis. Pre-admission prescription opioid use was determined, and a multivariable negative binomial regression analysis used to explore post-discharge opioid use.

RESULTS

A total of 7147 burn patients were matched with 6810 pancreatitis patients and with 28 184 individuals from the general population. Pre-admission opioid use was higher in the burn and pancreatitis cohorts (29% and 40%, respectively) compared with the general population (17%). Opioid use increased in both burn and pancreatitis cohorts after discharge (41% and 53%, respectively), although patients with pancreatitis were at even higher risk of increased opioid use in an adjusted analysis (incidence rate ratio 1.43). Female sex, lower socioeconomic status, ICU admission, pre-injury opioid use, and a history of excess alcohol use were all associated with an increase in opioid prescriptions after discharge.

CONCLUSIONS

Opioid use is high in those admitted with a burn injury or acute pancreatitis when compared with the general population, increasing further after hospital discharge. Female sex and socioeconomic deprivation are among factors that make increased opioid use more likely, although this phenomenon seems even more pronounced in those with acute pancreatitis compared with burn injuries.

Clinical and Demographic Factors Associated with Receiving an Opioid Prescription following Admission to the Pediatric Intensive Care Unit

Opioids are commonly used to treat pain in the pediatric intensive care unit (PICU), and many children receive opioid prescription(s) at discharge. The frequency of opioid prescriptions at discharge and associations with individual characteristics and clinical factors are unknown. This study aimed to identify (1) the number of children who receive an opioid prescription at PICU discharge and (2) the demographic and clinical factors associated with receiving an opioid prescription. Data were collected via the electronic medical record. The sample was 3345 children (birth to 18 years) admitted to the PICU and discharged to home or an inpatient rehabilitation setting. In total, 23.7% of children were prescribed an opioid at discharge. There were group differences in who received opioid prescriptions (yes/no) related to PICU diagnosis, length of hospital stay, number of days on mechanical ventilation, number of previous hospitalizations, organ dysfunction score, and admission type (surgical versus non-surgical). Binary logistic regression models examined predictors of opioid prescription at discharge for the total sample and diagnostic subgroups. Older age and surgical admission type were the most consistent predictors of receiving an opioid prescription. Future research should examine prescription usage patterns and how use of opioids is associated with pain and functional outcomes over time.

Neurological toll of COVID-19

The first case of coronavirus illness was discovered in Wuhan, China, in January 2020 and quickly spread worldwide within the next couple of months. The condition was initially only linked with respiratory disorders. After the evolution of various variants of the SARS-CoV-2, the critical impact of the virus spread to multiple organs and soon, neurological disorder manifestations started to appear in the infected patients. The review is focused on the manifestation of various neurological disorders linked with both the central nervous system and peripheral nervous system. Disorders such as cytokine release syndrome, encephalitis, acute stroke, and Bell's palsy are given specific attention and psychological manifestations are also investigated. For a clear conclusion, cognitive impairment, drug addiction disorders, mood and anxiety disorders, and post-traumatic stress disorder are all fully examined. The association of the SARS-CoV-2 with neurological disorders and pathway is yet to be clear. For better understanding, the explanation of the possible mechanism of viral infection influencing the nervous system is also attempted in the review. While several vaccines and drugs are already involved in treating the SARS-CoV-2 condition, the disease is still considered fatal and more likely to leave permanent neurological damage, which leads to an essential requirement for more research to explore the neurological toll of the COVID-19 disease.

Nonopioid analgesics for analgesia in critically ill patients: Friends, enemies, or collaborators

Patients in intensive care units (ICUs) experience pain, which they describe as a significant cause of stress during treatment. It can progress to chronic pain and significantly affect the quality of life. Opioids have long been the backbone of ICU pain therapy. The consequences of their long-term use are known today, such as prolonged ICU stay and mechanical ventilation, resulting in increased treatment costs. Additionally, abstinence syndrome is a consequence of abrupt opioid withdrawal. Also, there is a risk of tolerance and hyperalgesia after prolonged opioid use. Globally, opioid dependence after hospital opioid treatment is alarming, although there is still a lack of data on its incidence after ICU. Multimodal analgesia enables comfort to the patient, opioid-sparing, and avoidance of side effects of non-opioid analgesics. Nonsteroidal anti-inflammatory drugs (NSAIDs) are a broad group of drugs recommended with paracetamol to treat mild to moderate acute postoperative pain. Although often prescribed by intensivists, their use in treating painful conditions in ICU is controversial due to the possible consequences on the organs of critically ill patients. Due to the inhibition of cyclooxygenases, NSAIDs indirectly cause vasoconstriction of the renal arteries and arterioles, leading to kidney damage. NSAIDs inhibit platelet aggregation and may predispose to bleeding. Analgesia of a critically ill patient is a important part of their treatment, however it can be challenging in certain patients. Numerous combinations of pharmacological and non-pharmacological approaches can be adapted to the patient's current characteristics.

Determinants of pain assessment documentation in intensive care units

PURPOSE

The underassessment of pain is a major barrier to effective pain management, and the lack of pain assessment documentation has been associated with negative patient outcomes. This study aimed to 1) describe the contextual factors related to pain assessment and management in five Québec intensive care units (ICUs); 2) describe their pain assessment documentation practices; and 3) identify sociodemographic and clinical determinants related to pain assessment documentation.

METHODS

A descriptive-correlational retrospective design was used. Sociodemographic data (i.e., age, sex), clinical data (i.e., diagnosis, mechanical ventilation, level of consciousness, severity of illness, opioids, sedatives), and pain assessments were extracted from 345 medical charts of ICU admissions from five teaching hospitals between 2017 and 2019. Descriptive statistics and multiple linear regression were performed.

RESULTS

All sites reported using the 0-10 numeric rating scale, but the implementation of a behavioural pain scale was variable across sites. A median of three documented pain assessments were performed per 24 hr, which is below the minimal recommendation of eight to 12 pain assessments per 24 hr. Overall, pain assessment was present in 70% of charts, but only 20% of opioid doses were followed by documented pain reassessment within one hour post-administration. Higher level of consciousness (β = 0.37), using only breakthrough doses (β = 0.24), and lower opioid doses (β = -0.21) were significant determinants of pain assessment documentation (adjusted R2 = 0.25).

CONCLUSION

Pain assessment documentation is suboptimal in ICUs, especially for patients unable to self-report or those receiving higher opioid doses. Study findings highlight the need to implement tools to optimize pain assessment and documentation.

Effect of Opioids on Sleep

Opioid medications are often used to manage pain in the intensive care unit. Opioids, whether used as recreational drugs or for hospital patient pain management, impact the quality of sleep. Nurses should assess for pain and provide appropriate amounts of pain medications, while minimizing opioid use once the patient can tolerate non-narcotic medications. Nurses should assess the intensive care unit patient's sleep quality and be mindful of the effect that opioid medications have on sleep quality.

Long-term outcomes after critical illness: recent insights

Intensive care survivors often experience post-intensive care sequelae, which are frequently gathered together under the term “post-intensive care syndrome” (PICS). The consequences of PICS on quality of life, health-related costs and hospital readmissions are real public health problems. In the present Viewpoint, we summarize current knowledge and gaps in our understanding of PICS and approaches to management.

Reducing Opioid Use in Patients Undergoing Cardiac Surgery - Preoperative, Intraoperative, and Critical Care Strategies

Patients undergoing cardiothoracic surgery are exposed to opioids in the operating room and intensive care unit and after hospital discharge. Opportunities exist to reduce perioperative opioid use at all stages of care and include alternative oral and intravenous medications, novel intraoperative regional anesthetic techniques, and postoperative opioid-sparing sedative and analgesic strategies. In this review, currently used and investigational strategies to reduce the opioid burden for cardiothoracic surgical patients are explored.

Adjuvant Analgesic Use in the Critically Ill: A Systematic Review and Meta-Analysis

Supplemental Digital Content is available in the text.

This systematic review and meta-analysis addresses the efficacy and safety of nonopioid adjunctive analgesics for patients in the ICU.

Using a clinical judgement model to understand the impact of validated pain assessment tools for burn clinicians and adult patients in the ICU: A multi-methods study

BACKGROUND

Intensive care (ICU) patients' burn pain is difficult to assess, communicate and address, risking chronic pain syndromes and psychological morbidity.

AIMS

To understand how the introduction of validated pain tools (Critical Care Pain Observation Tool [CPOT], Numerical Rating Scale [NRS], Pain Assessment in Advanced Dementia [PAINAD]) affected clinical judgement processes, analgesia/sedation administration and the experience of burn-injured patients.

METHODS

Consecutive chart review compared type and amount of analgesia/sedation administered, ventilation time and length of ICU/hospital stay between consecutive burn patients pre- and 6-months post-intervention (n=70). Analysis of 36 qualitative interviews with ICU clinicians (n=12) and burn-injured adults (n=12) pre- and post-intervention was guided by Tanner's (2006) Clinical Judgement Model.

RESULTS

Overall, there was a significant increase in morphine (P=0.04) and propofol (P=0.04) use and a trend towards increased paracetamol (P=0.06) use post-intervention. There was a trend towards greater Midazolam use for TBSA<20% (P=0.06), and significantly increased propofol use for TBSA≥20% (P=0.03). Ventilation time and ICU/hospital length of stay were unchanged. Qualitative analysis revealed complex clinical judgement dependent on the context of the patient's situation, unit culture, background beliefs of clinicians and in knowing the patient. Whilst the CPOT and NRS enhanced analytic reasoning and pain advocacy, the PAINAD appeared redundant.

CONCLUSIONS

Effective pain assessment, management and advocacy are assisted by evidence-based assessment practices.

Potential mechanism of action of Ixeris sonchifolia extract injection against cardiovascular diseases revealed by combination of HPLC-Q-TOF-MS, virtual screening and systems pharmacology approach

Ixeris sonchifolia extract injection, a Chinese medicine preparation named as Kudiezi injection (KDZI) in China, has been widely used for the treatment of cardiovascular diseases (CVDs) in recent years. Owing to the component complexity of the preparation, the study on the effect mechanism of the herbal medicine against CVDs is a big challenge. In this research, HPLC-Q-TOF-MS was used to analyze the constituents of the preparation, disclosing that the KDZI mainly consists of 10 ingredients, namely 3-caffeoylquinic acid (KDZI-1), 4-caffeoylquinic acid (KDZI-2), 5-caffeoylquinic acid (KDZI-3), apigenin-7-O-β-d-glucuronide (KDZI-4), caffeic acid (KDZI-5), chicoric acid (KDZI-6), caftaric acid (KDZI-7), luteolin-7-O-β-d-gentiobioside (KDZI-8), luteolin-7-O-β-d-glucopyranoside (KDZI-9) and luteolin-7-O-β-d-glucuronide (KDZI-10). Afterwards, target fishing and an integrated systems pharmacology approach combined with molecular docking (Sybyl 1.3 and AutoDock Vina) were adopted to predict the potential targets and pathways for the main ingredients in KDZI. As results, 39 protein targets and 9 KEGG pathways, possessing high relevance to the therapeutic effects of the ingredients of KDZI against CVDs, were screened out reasonably. The integrated pharmacology analysis suggested that KDZI could exert its therapeutic effects against CVDs possibly via multi-targets including EGFR, MAPK10, and SRC and multi-pathways referring to MAPK, focal adhesion, complement and coagulation cascades, etc. This research provides insights into understanding the comprehensive therapeutic effect and mechanism of the KDZI on CVDs.

Ixeris sonchifolia extract injection, a Chinese medicine preparation named as Kudiezi injection (KDZI) in China, has been widely used for the treatment of cardiovascular diseases (CVDs) in recent years.

The Effect of the Open and Closed System Suctions on Pain Severity and Physiological Indicators in Mechanically Ventilated Patients with Traumatic Brain Injury: A Randomised Controlled Trial

Objective

Tracheal suctioning can cause pain and physiological indicator variations in patients with traumatic brain injury (TBI). The aim of the present study was to compare pain severity and physiological indicator variations during the closed tracheal suction system (CTSS) and open tracheal suction system (OTSS) in patients with TBI.

Methods

This study was a clinical trial. Samples included all ventilated patients with TBI. The patients were randomly divided into the OTSS and CTSS groups. In both groups, the Critical Care Pain Observation Tool (CPOT) and physiological indicators were recorded by three nurses prior to suctioning, the end of suctioning and 5 min after suction completion. Data were analysed using the independent t-test and repeated measurement tests.

Results

A total of 112 patients participated in the present study. Before the interventions, the mean value of the Glasgow Coma Scale was 6.45±1.13, blood pressure 128.33±20.54, saturated oxygen in arterial blood (SpO₂) 96.74±2.76, respiratory rate (RR) 15.06±3.98, end-tidal CO2 (EtCO₂) 36.2±21.98, heart rate 82.18±42.33 and CPOT-based pain 0.43±0.94 in the patients. Independent t-test was used to compare CTSS and OTSS, suggesting significant differences with respect to the mean values of SpO₂, RR and EtCO₂ immediately after suctioning. This test showed significant differences between the two groups with respect to pain intensity at all three points of measurement. The two groups were also found to be significantly different with respect to RR measured 5 min after suctioning (p<0.05).

Conclusion

Compared to OTSS, CTSS can cause higher reductions in pain levels during and after suctioning in patients with head traumas and can also cause higher improvements in physiological indicators, such as RR, O₂ saturation and EtCO₂.

Long-Lasting Anti-Inflammatory and Antinociceptive Effects of Acute Ammonium Glycyrrhizinate Administration: Pharmacological, Biochemical, and Docking Studies

The object of the study was to estimate the long-lasting effects induced by ammonium glycyrrhizinate (AG) after a single administration in mice using animal models of pain and inflammation together with biochemical and docking studies. A single intraperitoneal injection of AG was able to produce anti-inflammatory effects in zymosan-induced paw edema and peritonitis. Moreover, in several animal models of pain, such as the writhing test, the formalin test, and hyperalgesia induced by zymosan, AG administered 24 h before the tests was able to induce a strong antinociceptive effect. Molecular docking studies revealed that AG possesses higher affinity for microsomal prostaglandin E synthase type-2 compared to type-1, whereas it seems to locate better in the binding pocket of cyclooxygenase (COX)-2 compared to COX-1. These results demonstrated that AG induced anti-inflammatory and antinociceptive effects until 24-48 h after a single administration thanks to its ability to bind the COX/mPGEs pathway. Taken together, all these findings highlight the potential use of AG for clinical treatment of pain and/or inflammatory-related diseases.