Comparison of analgesic efficacy of tramadol, morphine and methadone in cats undergoing ovariohysterectomy

OBJECTIVES

The aim of this study was to compare the analgesic efficacy and the effect on physiological variables and behavior of the use of tramadol, methadone and morphine as preoperative analgesia in healthy cats undergoing elective ovariohysterectomy.

METHODS

Cats undergoing ovariohysterectomy were randomly assigned to receive one of the following premedication treatments intramuscularly: methadone (0.2 mg/kg; n = 10); morphine (0.2 mg/kg; n = 10); or tramadol (3 mg/kg; n = 10). Induction of anesthesia was done with propofol, and maintenance of anesthesia was done with isoflurane. Intraoperative heart rate, arterial blood pressure, respiratory rate, end-tidal isoflurane concentration and frequency of rescue analgesia (fentanyl 2.5 µg/kg) were compared between groups. Postoperative analgesia was assessed using the UNESP-Botucatu Multidimensional Composite Pain Scale, and perioperative serum glucose, cortisol concentrations and postoperative rescue analgesia were evaluated.

RESULTS

Intraoperative rescue analgesia was required in 76.5% of cats at some time during surgery, and 27% of cats required postoperative rescue analgesia up to 6 h after extubation. There were no significant differences between groups with respect to intraoperative and postoperative rescue analgesia, pain scale scores and end-tidal isoflurane concentrations. In the immediate postoperative period, after extubation, most of the patients presented with hypothermia; however, 1-6 h postoperatively, hyperthermia was observed in most of the patients, and was most common in the tramadol group.

CONCLUSIONS AND CLINICAL RELEVANCE

Under the conditions of this study, methadone, morphine and tramadol produced satisfactory postoperative analgesia in most of the cats undergoing ovariohysterectomy, and the effects lasted up to 6 h postoperatively. Intraoperative analgesia was not sufficient in most cases. Significant cardiovascular or respiratory effects contraindicating the use of these drugs were not found. Postanesthetic hyperthermia occurred with all opioids studied and was more frequent in the tramadol group.

The impact of opioid administration on the incidence of postanaesthetic colic in horses

Effective management of postoperative pain is essential to ensure patient welfare, reduce morbidity and optimize recovery. Opioids are effective in managing moderate to severe pain in horses but concerns over their adverse effects on gastrointestinal (GI) motility and associated increased colic risk limit their widespread use. Studies investigating the impact of systemic opioids on both GI motility and colic incidence in horses have yielded inconclusive outcomes. Therefore, this retrospective study aims to assess the influence of systemic administration of butorphanol, morphine, and methadone on post-anaesthetic colic (PAC) incidence. Horses undergoing general anaesthesia for non-gastrointestinal procedures that were hospitalized for at least 72 h post-anaesthesia were included in this study. Anaesthetised horses were stratified by procedure type into horses undergoing diagnostic imaging without surgical intervention, emergency or elective surgery. In addition, patients were grouped by opioid treatment regime into horses receiving no opioids, intraanaesthetic, short- (<24 h) or long-term (>24 h) postoperative opioids. Administered opioids encompassed butorphanol, morphine and methadone. The number of horses showing signs of colic in the 72 h after anaesthesia was assessed for each group. A total of 782 horses were included, comprising 659 undergoing surgical procedures and 123 undergoing diagnostic imaging. The overall PAC incidence was 15.1%. Notably, horses undergoing diagnostic imaging without surgery had a significantly lower PAC rate of 6.5% compared to those undergoing surgery (16.7%, p = 0.0146). Emergency surgeries had a significantly lower PAC rate of 5.8% compared to elective procedures (18%, p = 0.0113). Of the 782 horses, 740 received intraoperative opioids and 204 postoperative opioids, 102 of which long-term (≥24 h). Neither intraoperative (p = 0.4243) nor short-term postoperative opioids (p = 0.5744) increased PAC rates. Notably, only the long-term (≥24 h) administration of morphine significantly increased PAC incidence to 34% (p = 0.0038). In contrast, long-term butorphanol (5.3% PAC, p = 0.8482) and methadone (18.4% PAC, p = 0.6161) did not affect PAC rates. In summary, extended morphine administration was the only opioid treatment associated with a significantly increased risk of PAC.

The Effect of Epidural Analgesia on Quality of Recovery (QoR) after Open Radical Nephrectomy: Randomized, Prospective, and Controlled Trial

No studies are currently evaluating the quality of recovery (QoR) after open radical nephrectomy (ORN) and epidural morphine analgesia. This was a randomized, prospective, and controlled study that explored the QoR on the first postoperative day after ORN. Eighty subjects were randomized into two groups. The first group received general anesthesia combined with epidural anesthesia and postoperative epidural analgesia with morphine and ropivacaine. The second group received general anesthesia and continuous postoperative intravenous analgesia with tramadol. Both groups received multimodal analgesia with metamizole. The primary outcome measure was the total QoR-40 score. The secondary outcome measures were QoR-15, QoR-VAS, and the visual analog scale (VAS) for pain, anxiety, and nausea. The median difference in the QoR-40 score after 24 postoperative hours between the two groups of patients was 10 (95% CI: 15 to 5), p < 0.0001. The median score and IQR of QoR-40 during the first 24 postoperative hours in the epidural group was 180 (9.5), and in the control group, it was 170 (13). The general independence test for secondary outcomes between groups was significant (p < 0.01). QoR-VAS was correlated with QoR-40 (r = 0.63, p ≤ 0.001) and with QoR-15 (r = 0.54, p ≤ 0.001). The total QoR-40 and QoR-15 alpha coefficients with a 95% CI were 0.88 (0.85-0.92) and 0.73 (0.64-0.81), respectively. There was a significant difference in the QoR between the epidural and the control groups after ORN. The QoR-40 and QoR-15 showed good convergent validity and reliability.

Neural Network Connectivity Following Opioid Dependence is Altered by a Common Genetic Variant in the µ-Opioid Receptor, OPRM1 A118G

Opioid use disorder is a chronic, relapsing disease associated with persistent changes in brain plasticity. A common single nucleotide polymorphism (SNP) in the µ-opioid receptor gene, OPRM1 A118G, is associated with altered vulnerability to opioid addiction. Reconfiguration of neuronal connectivity may explain dependence risk in individuals with this SNP. Mice with the equivalent Oprm1 variant, A112G, demonstrate sex-specific alterations in the rewarding properties of morphine and heroin. To determine whether this SNP influences network-level changes in neuronal activity, we compared FOS expression in male and female mice that were opioid-naive or opioid-dependent. Network analyses identified significant differences between the AA and GG Oprm1 genotypes. Based on several graph theory metrics, including small-world analysis and degree centrality, we show that GG females in the opioid-dependent state exhibit distinct patterns of connectivity compared to other groups of the same genotype. Using a network control theory approach, we identified key cortical brain regions that drive the transition between opioid-naive and opioid-dependent brain states; however, these regions are less influential in GG females leading to sixfold higher average minimum energy needed to transition from the acute to the dependent state. In addition, we found that the opioid-dependent brain state is significantly less stable in GG females compared to other groups. Collectively, our findings demonstrate sex- and genotype-specific modifications in local, mesoscale, and global properties of functional brain networks following opioid exposure and provide a framework for identifying genotype differences in specific brain regions that play a role in opioid dependence.

Repeated pre-exposure to morphine inhibited the amnesic effect of ethanol on spatial memory: Involvement of CaMKII and BDNF

Evidence has suggested that addiction and memory systems are related, but the signaling cascades underlying this interaction have not been completelyealed yet. The importance of calcium-calmodulin-dependent protein kinase II (CaMKII) and brain-derived neurotrophic factor (BDNF) in the memory processes and also in drug addiction has been previously established. In this present investigation, we examined the effects of repeated morphine pretreatment on impairment of spatial learning and memory acquisition induced by systemic ethanol administration in adult male rats. Also, we assessed how these drug exposures influence the expression level of CaMKII and BDNF in the hippocampus and amygdala. Animals were trained by a single training session of 8 trials, and a probe test containing a 60-s free-swim without a platform was administered 24 h later. Before training trials, rats were treated with a once-daily subcutaneous morphine injection for 3 days followed by a 5-day washout period. The results showed that pre-training ethanol (1 g/kg) impaired spatial learning and memory acquisition and down-regulated the mRNA expression of CaMKII and BDNF. The amnesic effect of ethanol was suppressed in morphine- (15 mg/kg/day) pretreated animals. Furthermore, the mRNA expression level of CaMKII and BDNF increased significantly following ethanol administration in morphine-pretreated rats. Conversely, this improvement in spatial memory acquisition was prevented by daily subcutaneous administration of naloxone (2 mg/kg) 15 min prior to morphine administration. Our findings suggest that sub-chronic morphine treatment reverses ethanol-induced spatial memory impairment, which could be explained by modulating CaMKII and BDNF mRNA expressions in the hippocampus and amygdala.

Morphine exposure modulates dimensional bias and set formation in anthropoids

Humans demonstrate significant behavioural advantages with particular perceptual dimensions (such as colour or shape) and when the relevant dimension is repeated in consecutive trials. These dimension-related behavioural modulations are significantly altered in neuropsychological and addiction disorders; however, their underlying mechanisms remain unclear. Here, we studied whether these behavioural modulations exist in other trichromatic primate species and whether repeated exposure to opioids influences them. In a target detection task where the target-defining dimension (colour or shape) changed trial by trial, humans exhibited shorter response time (RT) and smaller event-related electrodermal activity with colour dimension; however, macaque monkeys had shorter RT with shape dimension. Although the dimensional biases were in the opposite directions, both species were faster when the relevant dimension was repeated, compared with conditions when it changed, across consecutive trials. These indicate that both species formed dimensional sets and that resulted in a significant 'switch cost'. Scheduled and repeated exposures to morphine, which is analogous to its clinical and recreational use, significantly augmented the dimensional bias in monkeys and also changed the switch cost depending on the relevant dimension. These cognitive effects occurred when monkeys were in abstinence periods (not under acute morphine effects) but expressing significant morphine-induced conditioned place preference. These findings indicate that significant dimensional biases and set formation are evolutionarily preserved in humans' and monkeys' cognition and that repeated exposure to morphine interacts with their manifestation. Shared neural mechanisms might be involved in the long-lasting effects of morphine and expression of dimensional biases and set formation in anthropoids.

Comparative effects of epidural analgesia and intramuscular morphine on maternal and neonatal outcomes: a retrospective cohort study

BACKGROUND

The global practice of pain management during labor involves the use of epidural analgesia or intramuscular morphine. However, the impact of these methods on maternal and neonatal short-term outcomes remains uncertain.

OBJECTIVE

This study aimed to evaluate the effect of labor exposure to epidural analgesia and intramuscular morphine on neonatal intensive care unit admission rates and other associated maternal and neonatal outcomes such as sepsis, respiratory distress, instrumental delivery, birth trauma, low Apgar score, and chorioamnionitis.

STUDY DESIGN

A study at the Women's Wellness and Research Center in Qatar analyzed 7721 low-risk normal vaginal deliveries from January 2017 to April 2018. Results were analyzed using descriptive and backward stepwise multinomial regression analysis, categorizing outcomes on the basis of pain management during active labor.

RESULTS

Of the 7607 participants in the final sample, 2606 received epidural analgesia, 1338 received intramuscular morphine, 286 received both, and 3304 received neither. Multinomial regression analysis revealed no difference in neonatal intensive care unit admission in the epidural analgesia group or in the intramuscular morphine group compared with the group that received neither intervention. However, the analysis showed a significant association between the combined use of epidural analgesia and intramuscular morphine and neonatal intensive care unit admission due to respiratory depression (adjusted odds ratio, 8.63; 95% confidence interval, 1.07-69.46; P=.04). Moreover, there was a significant association between prolonged duration of the second stage of labor and receiving epidural analgesia alone (adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.02; P<.001) or the combination of epidural analgesia and intramuscular morphine (adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.03; P<.001). In addition, the combined use of epidural analgesia and intramuscular morphine was associated with gestational age (adjusted odds ratio, 1.86; 95% confidence interval, 1.19-2.90; P=.01) and infant sex (adjusted odds ratio, 3.72; 95% confidence interval, 1.54-9.01; P=.003). Intramuscular morphine alone was only linked to low Apgar score at 1 minute (adjusted odds ratio, 6.29; 95% confidence interval, 1.33-29.83; P=.02).

CONCLUSION

In low-risk mothers, combining epidural analgesia and intramuscular morphine during labor increases NICU admission risk due to respiratory depression. However, the individual use of either method shows distinct clinical profile. Further research is warranted to enhance understanding and optimize pain management protocols.

Comparison of different sustained-release opioids and acute respiratory conditions in patients with cancer and chronic kidney disease

STUDY OBJECTIVE

Few data are available on the association between the use of oxycodone in patients with chronic kidney disease (CKD) and acute respiratory conditions. The aim of this study was to investigate whether oxycodone is associated with an increased risk of acute respiratory conditions in patients with cancer and CKD compared with other opioids.

DESIGN AND SETTING

The data were obtained from a claims database in Japan. Patients with cancer and CKD who had received sustained-release opioids, including oral oxycodone, oral morphine, or transdermal fentanyl, between April 2014 and May 2021 were selected. The primary outcome was defined as an acute respiratory condition. Data for age and sex, morphine equivalent daily dose, concomitant use of specified medications, comorbidities defined based on the modified Charlson comorbidity index, substance use disorder, and lung cancer or metastatic lung cancer were investigated as covariates. Distribution of acute respiratory conditions was compared among the three sustained-release opioid groups using the log-rank test. Estimates of the incidence of acute respiratory conditions were compared among the groups using a Cox proportional hazards model with time-varying variables.

MAIN RESULTS

A significant difference in the distribution of acute respiratory conditions was found among the three groups (p < 0.01). Cox regression analysis showed a significantly higher risk of acute respiratory conditions with morphine (hazard ratio [HR]: 3.04, 95% confidence interval [CI]: 1.07-8.65, p = 0.04) compared with oxycodone but no significant difference in risk with oxycodone (HR 0.67, 95% CI: 0.32-1.38, p = 0.27) compared with fentanyl.

CONCLUSIONS

The findings suggest that the risk of acute respiratory conditions may be lower in patients with CKD who use oxycodone for cancer pain than in those who use morphine. Additionally, no difference in the risk of acute respiratory conditions was found between oxycodone and fentanyl use.

Intravenous Ketamine for Pain Control in First-Trimester Surgical Abortion: Interim Analysis of a Randomized Controlled Trial

OBJECTIVES

Surgical abortion is common, with most completed in the first trimester. Gold standard pain control is intravenous (IV) fentanyl and midazolam, requiring continuous cardio-respiratory monitoring, a potential challenge where this monitoring is unavailable. Ketamine is a sedative and analgesic without the cardio-respiratory depression risk associated with IV opioids, representing a potential alternative. Investigating non-opiate pain control methods is imperative given the context of the opioid crisis. This is an interim analysis of 45 participants from a randomized controlled trial comparing IV ketamine, oral morphine, and IV fentanyl for pain control in first-trimester surgical abortion. We hypothesize that ketamine will provide better pain control than morphine.

METHODS

This is a double-blind, single-centre superiority trial of 3 parallel groups. Participants were ≥18 years old with confirmed intrauterine pregnancy of gestational age <12 weeks. Pain was assessed using the Visual Analogue Scale and the Wong-Baker Faces Pain Rating Scale.

RESULTS

In total, 2 participants were excluded post-randomization for 43 treated. Findings indicate that ketamine (n = 14; M = 0.7; 95% CI 0.1-1.3) provides better intra-operative pain control than morphine (n = 15, M = 4.4, 95% CI 2.9-5.9) and fentanyl (n = 14; M = 4.3; 95% CI 3.0-5.6; P < 0.001). The ketamine group was more satisfied with the anaesthetic method than the morphine group (P = 0.017). No group experienced serious adverse events.

CONCLUSIONS

Findings support continuation of the randomized controlled trial and highlight ketamine as a compelling non-opiate pain control option in first-trimester surgical abortion. Ketamine use may represent more optimal pain control in settings where continuous cardio-respiratory monitoring is unavailable.

Individual Factors Modifying Postoperative Pain Management in Elective Total Hip and Total Knee Replacement Surgery

Total hip and knee replacements are the most common orthopedic procedures performed due to osteoarthritis. Pain is an intrinsic symptom accompanying osteoarthritis, persisting long before surgery, and continuing during the preoperative and postoperative periods. Appropriate pain management after surgery determines the comfort, duration, and cost of hospitalization, as well as the effectiveness of postoperative rehabilitation. Individual differences in pain perception and tolerance in orthopedic patients remain an important research topic. Therefore, the aim of this study was to investigate the predictors of analgesic requirements (morphine, acetaminophen, and ketoprofen), including individual pain threshold and tolerance, body mass index (BMI), diabetes, and beliefs about pain control in patients undergoing elective hip or knee arthroplasty using a multilevel regression model (N = 147, 85 women, 62 men, 107 after hip replacement, and 40 after knee replacement). Results: Higher pain tolerance was associated with a lower dose of morphine per kg after surgery. Patients undergoing hip surgery received a lower dose of ketoprofen than patients undergoing knee surgery. The more the patient believed in personal pain control, the stronger the negative relationship between pain tolerance and morphine requirement. The lowest doses were given to patients with the highest pain tolerance and the greatest belief in personal control. Factors such as belief in pain control and pain tolerance should be considered in comprehensive postoperative pain management in orthopedic patients to reduce opioid doses and, thus, side effects.

Analgesic Efficacy of Oxycodone in Postoperative Dressings after Surgical Treatment of Burn Wounds: A Randomised Controlled Trial

INTRODUCTION

This study aimed to assess the analgesic efficacy of oxycodone at doses of 10 mg and 20 mg in dressings after surgery of burn wounds.

MATERIAL AND METHODS

Twenty adult patients who underwent surgical treatment of third-degree burn wounds under general anaesthesia were included. Burn wounds were treated with dressings, to which oxycodone was added at 20 mg in Group 1 and 10 mg in Group 2. After the surgery, plasma oxycodone and noroxycodone concentrations were assayed, and pain intensity was assessed with Numerical Rating Scale (NRS).

RESULTS

In Group 1, no patient reported pain; in Group 2, four patients reported pain. The pain intensity, according to NRS, was 1-8. Plasma concentration of oxycodone in the blood serum was in the range of 1.24-3.15 ng/mL and 1.09-1.28 ng/mL in Group 1 and Group 2, respectively. Noroxycodone was not detected in the plasma. Adverse effects were not observed in any of the treated patients.

CONCLUSIONS

Oxycodone in dressings provides patients with adequate and safe analgesia.

J-2156, a small molecule somatostatin type 4 receptor agonist, alleviated hindpaw hypersensitivity in the streptozotocin-induced rat model of painful diabetic neuropathy but with a 2-fold decrease in potency at an advanced stage in the model, mimicking morphine

There is a large unmet need for novel pain-killers to improve relief of painful diabetic neuropathy (PDN). Herein, we assessed the efficacy of the somatostatin type 4 (SST4) receptor agonist, J-2156, for relief of PDN in rats. Diabetes was induced with streptozotocin (STZ; 70 mg/kg) and bilateral hindpaw hypersensitivity was fully developed by 8-week post-STZ. In the intervals, 8-12-weeks (morphine-sensitive phase; Phase 1) and 16-18-weeks (morphine-hyposensitive phase; Phase 2) post-STZ, rats received a single dose of intraperitoneal (i.p.) J-2156 (10, 20, 30 mg/kg), gabapentin (100 mg/kg i.p.), subcutaneous morphine (1 mg/kg) or vehicle. Hindpaw withdrawal thresholds (PWTs) were assessed using von Frey filaments pre-dose and at regular intervals over 3-h post-dose. In Phase 1, J-2156 at 30 mg/kg evoked significant anti-allodynia in the hindpaws with maximal effect at 1.5 h compared with 1 h for gabapentin and morphine. The durations of action for all three compounds were greater than 3 h. The corresponding mean (±SEM) extent and duration of anti-allodynia (ΔPWT AUC) for gabapentin did not differ significantly from that for J-2156 (30 mg/kg) or morphine. However, in Phase 2, the ΔPWT AUC for morphine was reduced to approximately 25% of that in Phase 1, mirroring our previous work. Similarly, the mean (±SEM) ΔPWT AUC for J-2156 (30 mg/kg) in Phase 2 was approximately 45% of that for Phase 1 whereas for gabapentin the mean (±SEM) ΔPWT AUCs did not differ significantly (p > 0.05) between the two phases. Our findings further describe the preclinical pain relief profile of J-2156 and complement previous work in rat models of inflammatory pain, neuropathic pain and low back pain. SST4 receptor agonists hold promise as novel therapeutics for the relief of PDN, a type of peripheral neuropathic pain that is often intractable to relief with clinically used drug treatment options.

Comparison of the ED50 of prophylactic butorphanol in preventing morphine-induced pruritus with or without palonosetron: a prospective, double-blinded, randomized dose-response trial using an up-down sequential allocation method

BACKGROUND

Butorphanol has been used to reduce the incidence and severity of neuraxial morphine-induced pruritus. Palonosetron is a commonly used antiemetic for the prevention of postoperative nausea and vomiting. The aim of our study was to compare the effective dose in 50% of subjects (ED50) of intravenous butorphanol infusion with or without a single intravenous bolus of palonosetron for preventing pruritus induced by epidural administration of morphine.

METHODS

A total of 120 parturients were randomly assigned to receive an intravenous bolus injection of palonosetron plus continuous infusion of butorphanol (Group P + B) or an intravenous bolus of saline plus continuous infusion of butorphanol (Group B) after epidural administration of morphine. The antipruritic effect was graded as satisfactory (numerical rating scale (NRS) of pruritus ≤3) or unsatisfactory (NRS >3) within 48 h after morphine treatment. The first patient in each group received butorphanol infusion at a rate of 4 µg/kg/h. The infusion dose for each subsequent patient in the corresponding group was increased by 0.2 µg/kg/h after an unsatisfactory response or decreased by 0.2 µg/kg/h after a satisfactory response. The ED50 was calculated for each group and compared using up-down sequential analysis.

RESULTS

The ED50 (mean [95% confidence interval (CI)]) of the dose of intravenous butorphanol infusion for preventing moderate to severe pruritus was lower in Group P + B (3.29 µg/kg/min [3.25-3.34 µg/kg/min]) than in Group B (3.57 µg/kg/min [3.47-3.67 µg/kg/min]) (p < 0.05).

CONCLUSIONS

Under the conditions of the present study, a prophylactic use of 0.25 mg palonosetron reduced the ED50 of prophylactic infusion of butorphanol by approximately 8% to achieve a satisfactory antipruritic effect after epidural morphine for post-caesarean analgesia.

The Effect of Prenatal and Neonatal Fluoride Exposure to Morphine-Induced Neuroinflammation

Physical dependence is associated with the formation of neuroadaptive changes in the central nervous system (CNS), both at the molecular and cellular levels. Various studies have demonstrated the immunomodulatory and proinflammatory properties of morphine. The resulting neuroinflammation in drug dependence exacerbates substance abuse-related behaviors and increases morphine tolerance. Studies prove that fluoride exposure may also contribute to the development of neuroinflammation and neurodegenerative changes. Morphine addiction is a major social problem. Neuroinflammation increases tolerance to morphine, and neurodegenerative effects caused by fluoride in structures related to the development of dependence may impair the functioning of neuronal pathways, change the concentration of neurotransmitters, and cause memory and learning disorders, which implies this element influences the development of dependence. Therefore, our study aimed to evaluate the inflammatory state of selected brain structures in morphine-dependent rats pre-exposed to fluoride, including changes in cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) expression as well as microglial and astroglial activity via the evaluation of Iba1 and GFAP expression. We provide evidence that both morphine administration and fluoride exposure have an impact on the inflammatory response by altering the expression of COX-1, COX-2, ionized calcium-binding adapter molecule (Iba1), and glial fibrillary acidic protein (GFAP) in brain structures involved in dependence development, such as the prefrontal cortex, striatum, hippocampus, and cerebellum. We observed that the expression of COX-1 and COX-2 in morphine-dependent rats is influenced by prior fluoride exposure, and these changes vary depending on the specific brain region. Additionally, we observed active astrogliosis, as indicated by increased GFAP expression, in all brain structures of morphine-dependent rats, regardless of fluoride exposure. Furthermore, the effect of morphine on Iba1 expression varied across different brain regions, and fluoride pre-exposure may influence microglial activation. However, it remains unclear whether these changes are a result of the direct or indirect actions of morphine and fluoride on the factors analyzed.

Ibuprofen for acute postoperative pain in children

BACKGROUND

Children often require pain management following surgery to avoid suffering. Effective pain management has consequences for healing time and quality of life. Ibuprofen, a frequently used non-steroidal anti-inflammatory drug (NSAID) administered to children, is used to treat pain and inflammation in the postoperative period.

OBJECTIVES

1) To assess the efficacy and safety of ibuprofen (any dose) for acute postoperative pain management in children compared with placebo or other active comparators. 2) To compare ibuprofen administered at different doses, routes (e.g. oral, intravenous, etc.), or strategies (e.g. as needed versus as scheduled).

SEARCH METHODS

We used standard Cochrane search methods. We searched CENTRAL, MEDLINE, Embase, CINAHL and trials registries in August 2023.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in children aged 17 years and younger, treated for acute postoperative or postprocedural pain, that compared ibuprofen to placebo or any active comparator. We included RCTs that compared different administration routes, doses of ibuprofen and schedules.

DATA COLLECTION AND ANALYSIS

We adhered to standard Cochrane methods for data collection and analysis. Our primary outcomes were pain relief reported by the child, pain intensity reported by the child, adverse events, and serious adverse events. We present results using risk ratios (RR) and standardised mean differences (SMD), with the associated confidence intervals (CI). We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included 43 RCTs that enroled 4265 children (3935 children included in this review). We rated the overall risk of bias at the study level as high or unclear for 37 studies that had one or several unclear or high risk of bias judgements across the domains. We judged six studies as having a low risk of bias across all domains. Ibuprofen versus placebo (35 RCTs) No studies reported pain relief reported by the child or a third party, or serious adverse events. Ibuprofen probably reduces child-reported pain intensity less than two hours postintervention compared to placebo (SMD -1.12, 95% CI -1.39 to -0.86; 3 studies, 259 children; moderate-certainty evidence). Ibuprofen may reduce child-reported pain intensity, two hours to less than 24 hours postintervention (SMD -1.01, 95% CI -1.24 to -0.78; 5 studies, 345 children; low-certainty evidence). Ibuprofen may result in little to no difference in adverse events compared to placebo (RR 0.79, 95% CI 0.51 to 1.23; 5 studies, 384 children; low-certainty evidence). Ibuprofen versus paracetamol (21 RCTs) No studies reported pain relief reported by the child or a third party, or serious adverse events. Ibuprofen likely reduces child-reported pain intensity less than two hours postintervention compared to paracetamol (SMD -0.42, 95% CI -0.82 to -0.02; 2 studies, 100 children; moderate-certainty evidence). Ibuprofen may slightly reduce child-reported pain intensity two hours to 24 hours postintervention (SMD -0.21, 95% CI -0.40 to -0.02; 6 studies, 422 children; low-certainty evidence). Ibuprofen may result in little to no difference in adverse events (0 events in each group; 1 study, 44 children; low-certainty evidence). Ibuprofen versus morphine (1 RCT) No studies reported pain relief or pain intensity reported by the child or a third party, or serious adverse events. Ibuprofen likely results in a reduction in adverse events compared to morphine (RR 0.58, 95% CI 0.40 to 0.83; risk difference (RD) -0.25, 95% CI -0.40 to -0.09; number needed to treat for an additional beneficial outcome (NNTB) 4; 1 study, 154 children; moderate-certainty evidence). Ibuprofen versus ketorolac (1 RCT) No studies reported pain relief or pain intensity reported by the child, or serious adverse events. Ibuprofen may result in a reduction in adverse events compared to ketorolac (RR 0.51, 95% CI 0.27 to 0.96; RD -0.29, 95% CI -0.53 to -0.04; NNTB 4; 1 study, 59 children; low-certainty evidence).

AUTHORS' CONCLUSIONS

Despite identifying 43 RCTs, we remain uncertain about the effect of ibuprofen compared to placebo or active comparators for some critical outcomes and in the comparisons between different doses, schedules and routes for ibuprofen administration. This is largely due to poor reporting on important outcomes such as serious adverse events, and poor study conduct or reporting that reduced our confidence in the results, along with small underpowered studies. Compared to placebo, ibuprofen likely results in pain reduction less than two hours postintervention, however, the efficacy might be lower at two hours to 24 hours. Compared to paracetamol, ibuprofen likely results in pain reduction up to 24 hours postintervention. We could not explore if there was a different effect in different kinds of surgeries or procedures. Ibuprofen likely results in a reduction in adverse events compared to morphine, and in little to no difference in bleeding when compared to paracetamol. We remain mostly uncertain about the safety of ibuprofen compared to other drugs.

A non-inferiority randomized controlled trial comparing nebulized ketamine to intravenous morphine for older adults in the emergency department with acute musculoskeletal pain

OBJECTIVE

Our study aimed to investigate the analgesic efficacy of nebulized ketamine in managing acute moderate-to-severe musculoskeletal pain in older emergency department (ED) patients compared with intravenous (IV) morphine.

METHODS

This was a non-inferiority, double-blind, randomized controlled trial conducted at a single medical centre. The patients aged 65 and older, who presented at the ED musculoskeletal pain within 7 days and had a pain score of 5 or more on an 11-point numeric rating scale (NRS), were included in the study. The outcomes were a comparison of the NRS reduction between nebulized ketamine and IV morphine 30 minutes after treatment, incidence of adverse events and rate of rescue therapy.

RESULTS

The final study included 92 individuals, divided equally into two groups. At 30 minutes, the difference in mean NRS between the nebulized ketamine and IV morphine groups was insignificant (5.2 versus 5.7). The comparative mean difference in the NRS change from baseline between nebulized ketamine and IV morphine [-1.96 (95% confidence interval-CI: -2.45 to -1.46) and -2.15 (95% CI: -2.64 to -1.66) = 0.2 (95% CI: -0.49 to 0.89)] did not exceed the non-inferiority margin of 1.3. The rate of rescue therapy did not differ between the groups. The morphine group had considerably higher incidence of nausea than the control group (zero patients in the ketamine group versus eight patients (17.4%) in the morphine group; P = 0.006).

CONCLUSIONS

Nebulized ketamine has non-inferior analgesic efficacy compared with IV morphine for acute musculoskeletal pain in older persons, with fewer adverse effects.

Developing mathematical models to compare and analyse the pharmacokinetics of morphine and fentanyl

Background and Aims

The two-compartment model is generally used in pharmacokinetics to illustrate the distribution and excretion of drugs. In this study, we evaluated the distribution patterns of morphine and fentanyl by using a two-compartment model.

Methods

Using numeric analysis techniques, non-linear ordinary differential equations were used to mathematically analyse drug distribution, transition, and concentration in the body compartments. Math Works, Inc., MATLAB, version 2023a, a programming tool, was used to characterise the impact of initial concentration and rate constants on the kinetics of the drug. For a definite therapeutic concentration of morphine and fentanyl in blood, pharmacokinetic characteristics were plotted.

Results

The study results showed the time taken by morphine and fentanyl to reach a target concentration in the blood that is sufficient to generate the preferred therapeutic effects. The mathematical models comparing morphine and fentanyl pharmacokinetics showed that fentanyl reached the target therapeutic concentration 125 minutes earlier than morphine and was metabolised and removed from the body more rapidly (44 minutes earlier than morphine).

Conclusion

These comparative mathematical models on morphine and fentanyl enable the determination of drug dosages and understanding of drug efficacy that facilitates optimising dosing regimens. The right choice between them can be made based on the time to reach the target therapeutic concentration in the blood, elimination time, severity of pain, and patient characteristics.

Patient Controlled Subcutaneous Analgesia of Hydromorphone Versus Morphine to Treat Moderate and Severe Cancer Pain: A Randomized Double-Blind Controlled Trial

CONTEXT

Hydromorphone and morphine are the common drugs used for the treatment of moderate to severe cancer pain. Patient controlled subcutaneous analgesia (PCSA) is an effective technique to manage cancer pain. However, few studies have been conducted to show the efficacy and safety of PCSA of hydromorphone for the relief of cancer pain.

OBJECTIVES

To explore the short-term efficacy and safety of PCSA elicited by hydromorphone for moderate to severe cancer pain.

METHODS

This was a single-center, randomized, active-controlled, double-blind trial (from April 2019 to August 2021). Sixty patients with moderate to severe cancer pain were randomized (1:1) to hydromorphone or morphine groups according to drug delivery by PCSA. The primary outcome was the pain intensity measured by a numerical rating scale (NRS) at 72 hours. Secondary outcomes included pain intensity measured by NRS at baseline, 15 minutes, 30 minutes, two hours, eight hours, 24 hours and 48 hours. The daily occurrence of breakthrough pain (BTP), impact of pain on quality of life measured by the brief pain inventory (BPI), the daily additional consumption of opioids and the incidence of adverse events were also recorded. Adverse events included nausea, vomiting, dizziness, constipation and respiratory depression.

RESULTS

A total of 57 patients (28 patients in the hydromorphone group and 29 patients in the morphine group) in the West China Hospital of Sichuan University were investigated. The mean (standard deviation [SD]) NRS in the two groups at baseline was 7.8 (1.7) in the hydromorphone group and 7.6 (1.7) in the morphine group, and at 72 hours were 3.4 (1.8) and 3.2 (1.5), respectively. The postoperative NRS in both groups was decreased significantly compared to baseline. The mean (SD) NRS at 30 minutes in the hydromorphone group was significantly lower than in the morphine group (3.9 [2.6] vs. 5.3 [2.1], P = 0.035). The daily occurrence of BTP in both groups at 48 hours and 72 hours decreased significantly compared to the corresponding baseline (P < 0.05), and there was no significant difference between the two groups. The total scores and sub-item scores of BPI at 24 hours and 72 hours after PCSA in both groups decreased significantly from baseline. A comparison of daily additional consumption of opioids between the two groups revealed no statistically significant difference. There were no significant differences in the incidences of nausea, vomiting, dizziness or constipation between the two groups (P > 0.05).

CONCLUSION

This study found that the PCSA of both hydromorphone and morphine could effectively and safely relieve short-term moderate to severe cancer pain. Of note, the PCSA of hydromorphone took effect more quickly than that of morphine.

Prescription opioids induced microbial dysbiosis worsens severity of chronic pancreatitis and drives pain hypersensitivity

Opioids, such as morphine and oxycodone, are widely used for pain management associated with chronic pancreatitis (CP); however, their impact on the progression and pain sensitivity of CP has never been evaluated. This report investigates the impact of opioid use on the severity of CP, pain sensitivity, and the gut microbiome. C57BL/6 mice were divided into control, CP, CP with morphine/oxycodone, and either morphine or oxycodone alone groups. CP was induced by administration of caerulein (50ug/kg/h, i.p. hourly x7, twice a week for 10 weeks). The mouse-to-pancreas weight ratio, histology, and Sirius red staining were performed to measure CP severity. Tail flick and paw pressure assays were used to measure thermal and mechanical pain. DNA was extracted from the fecal samples and subjected to whole-genome shotgun sequencing. Germ-free mice were used to validate the role of gut microbiome in sensitizing acute pancreatic inflammation. Opioid treatment exacerbates CP by increasing pancreatic necrosis, fibrosis, and immune-cell infiltration. Opioid-treated CP mice exhibited enhanced pain hypersensitivity and showed distinct clustering of the gut microbiome compared to untreated CP mice, with severely compromised gut barrier integrity. Fecal microbiota transplantation (FMT) from opioid-treated CP mice into germ-free mice resulted in pancreatic inflammation in response to a suboptimal caerulein dose. Together, these analyses revealed that opioids worsen the severity of CP and induce significant alterations in pain sensitivity and the gut microbiome in a caerulein CP mouse model. Microbial dysbiosis plays an important role in sensitizing the host to pancreatic inflammation.

No significant change of N6 -methyladenosine modification landscape in mouse brain after morphine exposure

OBJECTIVES

N6 -methyladenosine (m6 A) plays a crucial role in regulating neuroplasticity and different brain functions at the posttranscriptional level. However, it remains unknown whether m6 A modification is involved in acute and chronic morphine exposure.

MATERIALS AND METHODS

In this study, we conducted a direct comparison of m6 A levels and mRNA expression of m6 A-associated factors between morphine-treated and nontreated C57BL/6 wild-type mice. We established animal models of both acute and chronic morphine treatment and confirmed the rewarding effects of chronic morphine treatment using the conditioned place preference (CPP) assay. The activation status of different brain regions in response to morphine was assessed by c-fos staining. To assess overall m6 A modification levels, we employed the m6 A dot blot assay, while mRNA levels of m6 A-associated proteins were measured using a quantitative polymerase chain reaction (qPCR) assay. These analyses were performed to investigate whether and how m6 A modification and m6 A-associated protein expression will change following morphine exposure.

RESULTS

The overall m6 A methylation and mRNA levels of m6 A-associated proteins were not significantly altered in brain regions that were either activated or not activated during acute morphine stimulation. Similarly, the overall m6 A modification and mRNA levels of m6 A-associated proteins remained unaffected in several key brain regions associated with reward following chronic morphine exposure.

CONCLUSION

This study showed that the overall m6 A modification level and mRNA expression levels of m6 A-associated factors were not affected after acute and chronic morphine exposure in different brain regions, indicating m6 A modification may not be involved in brain response to morphine exposure.

Comparative Analysis of Intravenous Opioids Versus Thoracic Epidural Anesthesia in Fractured Rib Pain Management: A Systematic Review and Meta-Analysis

Rib fractures, common among trauma victims, lead to significant morbidity and mortality. Managing the associated pain is challenging, with IV opioids and thoracic epidural analgesia (TEA) being utilized. While epidural analgesia is often preferred for fractured rib pain, existing data encompasses both lumbar and thoracic approaches. This review aimed to compare TEA and IV opioids for persistent rib fracture pain. A comprehensive search across five databases yielded 987 articles, of which seven met the eligibility criteria. Outcomes were categorized into primary (pain reduction) and secondary (mortality, hospital/ICU stays, analgesia-related complications) endpoints. Analyzed with Review Manager (RevMan) Version 5.4.1 (2020; The Cochrane Collaboration, London, United Kingdom), the pooled data from two sources showed TEA significantly more effective in reducing pain than IV opioids (standardized mean difference (SMD): 2.23; 95%CI: 1.65-2.82; p < 0.00001). Similarly, TEA was associated with shorter ICU stays (SMD: 0.73; 95%CI: 0.33-1.13; p = 0.0004), while hospitalization duration showed no substantial difference (SMD: 0.82; 95%CI: -0.34-1.98). Mortality rates also did not significantly differ between TEA and IV opioids (risk ratio (RR): 1.20; 95%CI: 0.36-4.01; p = 0.77). Subgroup analysis revealed fewer pneumonia cases with TEA (RR: 2.06; 95%CI: 1.07-3.96; P = 0.03), with no notable disparities in other complications. While TEA's superiority in pain relief for rib fractures suggests it is the preferred analgesic, the recommendation's strength is tempered by the low methodological quality of supporting articles.

Ultramicronized N-palmitoylethanolamine Contributes to Morphine Efficacy Against Neuropathic Pain: Implication of Mast Cells and Glia

BACKGROUND

In the current management of neuropathic pain, in addition to antidepressants and anticonvulsants, the use of opioids is wide, despite their related and well-known issues.

OBJECTIVE

N-palmitoylethanolamine (PEA), a natural fatty-acid ethanolamide whose anti-inflammatory, neuroprotective, immune-modulating and anti-hyperalgesic activities are known, represents a promising candidate to modulate and/or potentiate the action of opioids.

METHODS

This study was designed to evaluate if the preemptive and morphine concomitant administration of ultramicronized PEA, according to fixed or increasing doses of both compounds, delays the onset of morphine tolerance and improves its analgesic efficacy in the chronic constriction injury (CCI) model of neuropathic pain in rats.

RESULTS

Behavioral experiments showed that the preemptive and co-administration of ultramicronized PEA significantly decreased the effective dose of morphine and delayed the onset of morphine tolerance. The activation of spinal microglia and astrocytes, commonly occurring both on opioid treatment and neuropathic pain, was investigated through GFAP and Iba-1 immunofluorescence. Both biomarkers were found to be increased in CCI untreated or morphine treated animals in a PEA-sensitive manner. The increased density of endoneural mast cells within the sciatic nerve of morphine-treated and untreated CCI rats was significantly reduced by ultramicronized PEA. The decrease of mast cell degranulation, evaluated in terms of reduced plasma levels of histamine and N-methyl-histamine metabolite, was mainly observed at intermediate-high doses of ultramicronized PEA, with or without morphine.

CONCLUSION

Overall, these results show that the administration of ultramicronized PEA in CCI rats according to the study design fully fulfilled the hypotheses of this study.

Effect of a Multidisciplinary Review Panel on Daily Morphine Milligram Equivalents for Patients With Chronic Pain

INTRODUCTION/OBJECTIVE

Physicians and other health care professionals are challenged regularly to balance managing pain for patients with chronic pain receiving chronic opioid therapy (COT) with following the national guidelines and standards regarding daily morphine milligram equivalents (MME). This quality improvement project aimed to determine the effect of referral to a multidisciplinary review panel on daily MME for patients receiving COT for chronic pain.

METHODS

This quality improvement project included patients who had an established relationship with a primary care or community internal medicine clinician at a large health care organization and were referred to a newly created multidisciplinary review panel for their recommendations regarding treatment of pain. Criteria for patient referral were diagnosis of a chronic, painful condition, and use of chronic opioid medications. These patients were selected and referred at the discretion of their primary care clinician from January 2, 2019, through December 31, 2020. Data for this project were collected at the time of initial referral to the panel and 6 months after recommendations. The daily MME were assessed at the 2 time points.

RESULTS

Thirteen patients were referred to the review panel during the project period. The median daily MME at the time of referral was 180. Daily MME decreased by a median of 14 MME after 6 months. The MME did not increase during the project period for any participants.

CONCLUSIONS

Referral of patients receiving COT to a multidisciplinary review panel may reduce their daily opioid dose.