Analysis of cardiohemodynamic and electrophysiological effects of morphine along with its toxicokinetic profile using the halothane-anesthetized dogs.

Although morphine has been used for treatment-resistant dyspnea in end-stage heart failure patients, information on its cardiovascular safety profile remains limited. Morphine was intravenously administered to halothane-anesthetized dogs (n=4) in doses of 0.1, 1 and 10 mg/kg/10 min with 20 min of observation period. The low and middle doses attained therapeutic (0.13 µg/mL) and supratherapeutic (0.97 µg/mL) plasma concentrations, respectively. The low dose hardly altered any of the cardiovascular variables except that the QT interval was prolonged for 10-15 min after its start of infusion. The middle dose reduced the preload and afterload to the left ventricle for 5-15 min, then decreased the left ventricular contractility and mean blood pressure for 10-30 min, and finally suppressed the heart rate for 15-30 min. Moreover, the middle dose gradually but progressively prolonged the atrioventricular conduction time, QT interval/QTcV, ventricular late repolarization period and ventricular effective refractory period without altering the intraventricular conduction time, ventricular early repolarization period or terminal repolarization period. A reverse-frequency-dependent delay of ventricular repolarization was confirmed. The high dose induced cardiohemodynamic collapse mainly due to vasodilation in the initial 2 animals by 1.9 and 3.3 min after its start of infusion, respectively, which needed circulatory support to treat. The high dose was not tested further in the remaining 2 animals. Thus, intravenously administered morphine exerts a rapidly appearing vasodilator action followed by slowly developing cardiosuppressive effects. Morphine can delay the ventricular repolarization possibly through IKr inhibition in vivo, but its potential to develop torsade de pointes will be small.

Pharmacokinetic and neuroimmune pharmacogenetic impacts on slow-release morphine cancer pain control and adverse effects.

The aim was to determine if opioid neuroimmunopharmacology pathway gene polymorphisms alter serum morphine, morphine-3-glucuronide and morphine-6-glucuronide concentration-response relationships in 506 cancer patients receiving controlled-release oral morphine. Morphine-3-glucuronide concentrations (standardised to 11 h post-dose) were higher in patients without pain control (median (interquartile range) 1.2 (0.7-2.3) versus 1.0 (0.5-1.9) µM, P = 0.006), whereas morphine concentrations were higher in patients with cognitive dysfunction (40 (20-81) versus 29 (14-60) nM, P = 0.02). TLR2 rs3804100 variant carriers had reduced odds (adjusted odds ratio (95% confidence interval) 0.42 (0.22-0.82), P = 0.01) of opioid adverse events. IL2 rs2069762 G/G (0.20 (0.06-0.52)), BDNF rs6265 A/A (0.15 (0.02-0.63)) and IL6R rs8192284 carrier (0.55 (0.34-0.90)) genotypes had decreased, and IL6 rs10499563 C/C increased (3.3 (1.2-9.3)), odds of sickness response (P ≤ 0.02). The study has limitations in heterogeneity in doses, sampling times and diagnoses but still suggests that pharmacokinetics and immune genetics co-contribute to morphine pain control and adverse effects in cancer patients.

Assessing the Impact of Morphine on Adverse Outcomes in ACS Patients Treated with P2Y12 Inhibitors: Insights from Multiple Real-World Evidence.

Purpose: Mechanistic studies showed that morphine may impair the antiplatelet effect of P2Y12 inhibitors. However, Several clinical studies with cardiovascular events as an outcome are contradictory, and the broader impact of this drug interaction on additional organ systems remains uncertain. With multisource data, this study sought to determine the effects of morphine interaction with P2Y12 inhibitors on major adverse outcomes comprehensively, and identify the warning indicators. Patients and Methods: Interaction signals were sought in 187,919 safety reports from the FDA Adverse Event Reporting System (FAERS) database, utilizing reporting odds ratios (repOR). In a cohort of 5240 acute coronary syndrome patients, the analyses were validated, and the biological effects of warning indicators were further studied with Mendelian randomization and mediation analysis. Results: Potential risk of renal system adverse events in patients cotreated with morphine is significantly higher in FAERS (repOR 4.83, 95% CI 4.42-5.28, false discovery rate adjusted-P =3.55*10-209). The analysis of in-house patient cohorts validated these results with an increased risk of acute kidney injury (adjusted OR: 1.65; 95% CI: 1.20 to 2.26), and we also found a risk of myocardial infarction in patients treated with morphine (adjusted OR: 1.55; 95% CI: 1.14 to 2.11). The Morphine group exhibited diminished Plateletcrit (PCT) levels post-surgery and lower PCT levels were associated with an increased risk of AKI. Conclusion: The administration of morphine in patients treated with P2Y12 receptor inhibitors should be carefully evaluated. PCT may serve as a potential warning indicator for morphine-related renal injury.

TET1-Lipid Nanoparticle Encapsulating Morphine for Specific Targeting of Peripheral Nerve for Pain Alleviation.

Background: Opioids are irreplaceable analgesics owing to the lack of alternative analgesics that offer opioid-like pain relief. However, opioids have many undesirable central side effects. Restricting opioids to peripheral opioid receptors could reduce those effects while maintaining analgesia. Methods: To achieve this goal, we developed Tet1-LNP (morphine), a neural-targeting lipid nanoparticle encapsulating morphine that could specifically activate the peripheral opioid receptor in the dorsal root ganglion (DRG) and significantly reduce the side effects caused by the activation of opioid receptors in the brain. Tet1-LNP (morphine) were successfully prepared using the thin-film hydration method. In vitro, Tet1-LNP (morphine) uptake was assessed in differentiated neuron-like PC-12 cells and dorsal root ganglion (DRG) primary cells. The uptake of Tet1-LNP (morphine) in the DRGs and the brain was assessed in vivo. Von Frey filament and Hargreaves tests were used to assess the antinociception of Tet1-LNP (morphine) in the chronic constriction injury (CCI) neuropathic pain model. Morphine concentration in blood and brain were evaluated using ELISA. Results: Tet1-LNP (morphine) had an average size of 131 nm. Tet1-LNP (morphine) showed high cellular uptake and targeted DRG in vitro. CCI mice treated with Tet1-LNP (morphine) experienced prolonged analgesia for nearly 32 h compared with 3 h with free morphine (p < 0.0001). Notably, the brain morphine concentration in the Tet1-LNP (morphine) group was eight-fold lower than that in the morphine group (p < 0.0001). Conclusion: Our study presents a targeted lipid nanoparticle system for peripheral neural delivery of morphine. We anticipate Tet1-LNP (morphine) will offer a safe formulation for chronic neuropathic pain treatment, and promise further development for clinical applications.

Intrathecal Morphine for Cardiac Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

ABSTRACT: Cardiac surgeries often result in significant postoperative pain, leading to considerable use of opioids for pain management. However, excessive opioid use can lead to undesirable side effects and chronic opioid use. This systematic review and meta-analysis aimed to evaluate whether preoperative intrathecal morphine could reduce postoperative opioid consumption in patients undergoing cardiac surgery requiring sternotomy. We conducted a systematic search of Cochrane, EMBASE, and MEDLINE databases from inception to May 2022 for randomized controlled trials that evaluated the use of intrathecal morphine in patients undergoing cardiac surgery. Studies that evaluated intrathecal administration of other opioids or combinations of medications were excluded. The primary outcome was postoperative morphine consumption at 24 h. Secondary outcomes included time to extubation and hospital length of stay. The final analysis included ten randomized controlled trials, with a total of 402 patients. The results showed that postoperative morphine consumption at 24 h was significantly lower in the intervention group (standardized mean difference -1.43 [-2.12, -0.74], 95% CI, P < 0.0001). There were no significant differences in time to extubation and hospital length of stay. Our meta-analysis concluded that preoperative intrathecal morphine is associated with lower postoperative morphine consumption at 24 h following cardiac surgeries, without prolonging the time to extubation. The use of preoperative intrathecal morphine can be considered part of a multimodal analgesic and opioid-sparing strategy in patients undergoing cardiac surgery.

Opioid Coprescription Through Risk Mitigation Guidance and Opioid Agonist Treatment Receipt.

Importance: At the onset of the COVID-19 pandemic, the government of British Columbia, Canada, released clinical guidance to support physicians and nurse practitioners in prescribing pharmaceutical alternatives to the toxic drug supply. These alternatives included opioids and other medications under the risk mitigation guidance (RMG), a limited form of prescribed safer supply, designed to reduce the risk of SARS-CoV-2 infection and harms associated with illicit drug use. Many clinicians chose to coprescribe opioid medications under RMG alongside opioid agonist treatment (OAT). Objective: To examine whether prescription of hydromorphone tablets or sustained-release oral morphine (opioid RMG) and OAT coprescription compared with OAT alone is associated with subsequent OAT receipt. Design, Setting, and Participants: This population-based, retrospective cohort study was conducted from March 27, 2020, to August 31, 2021, included individuals from 10 linked health administrative databases from British Columbia, Canada. Individuals who were receiving OAT at opioid RMG initiation and individuals who were receiving OAT and eligible but unexposed to opioid RMG were propensity score matched at opioid RMG initiation on sociodemographic and clinical variables. Data were analyzed between January 2023 and February 2024. Exposure: Opioid RMG receipt (≥4 days, 1-3 days, or 0 days of opioid RMG dispensed) in a given week. Main Outcome and Measures: The main outcome was OAT receipt, defined as at least 1 dispensed dose of OAT in the subsequent week. A marginal structural modeling approach was used to control for potential time-varying confounding. Results: A total of 4636 individuals (2955 [64%] male; median age, 38 [31-47] years after matching) were receiving OAT at the time of first opioid RMG dispensation (2281 receiving ongoing OAT and 2352 initiating RMG and OAT concurrently). Opioid RMG receipt of 1 to 3 days in a given week increased the probability of OAT receipt by 27% in the subsequent week (adjusted risk ratio, 1.27; 95% CI, 1.25-1.30), whereas receipt of opioid RMG for 4 days or more resulted in a 46% increase in the probability of OAT receipt in the subsequent week (adjusted risk ratio, 1.46; 95% CI, 1.43-1.49) compared with those not receiving opioid RMG. The biological gradient was robust to different exposure classifications, and the association was stronger among those initiating opioid RMG and OAT concurrently. Conclusions and Relevance: This cohort study, which acknowledged the intermittent use of both medications, demonstrated that individuals who were coprescribed opioid RMG had higher adjusted probability of continued OAT receipt or reengagement compared with those not receiving opioid RMG.

Low-dose short infusion ketamine as adjunct to morphine for acute long bone fracture in the emergency department: a randomized controlled trial.

BACKGROUND: Ketamine is recognized as an alternative for pain management; however, concerns about emergent adverse reactions have limited its widespread adoption. This study aimed to assess the efficacy of a short infusion of low-dose ketamine (LDK) compared to intravenous morphine (MOR) as adjunctive analgesia for acute long bone fracture pain. METHODS: This single-blinded, randomized controlled trial was conducted in a single emergency department. Patients with acute long bone fractures and numerical rating scale (NRS) pain scores ≥ 6 following an initial dose of intravenous morphine were assigned to receive either a LDK (0.3 mg/kg) over 15 min or intravenous MOR at a dose of 0.1 mg/kg administered over 5 min. Throughout a 120-min observation period, patients were regularly evaluated for pain level (0-10), side effects, and the need for additional rescue analgesia. RESULTS: A total of 58 subjects participated, with 27 in the MOR group and 31 in the LDK group. Demographic variables and baseline NRS scores were comparable between the MOR (8.3 ± 1.3) and LDK (8.9 ± 1.2) groups. At 30 min, the LDK group showed a significantly greater mean reduction in NRS scores (3.1 ± 2.03) compared to the MOR group (1.8 ± 1.59) (p = 0.009). Similarly, at 60 min, there were significant differences in mean NRS score reductions (LDK 3.5 ± 2.17; MOR mean reduction = 2.4, ± 1.84) with a p-value of 0.04. No significant differences were observed at other time intervals. The incidence of dizziness was higher in the LDK group at 19.4% (p = 0.026). CONCLUSION: Short infusion low-dose ketamine, as an adjunct to morphine, is effective in reducing pain during the initial 30 to 60 min and demonstrated comparability to intravenous morphine alone in reducing pain over the subsequent 60 min for acute long bone fractures. However, it was associated with a higher incidence of dizziness. TRIAL REGISTRATION: NMRR17318438970 (2 May 2018; www.nmrr.gov.my ).

Low doses of acetaminophen produce antidepressive-like effects through the opioid system in mice.

Acetaminophen (paracetamol) is one of the most popular analgesics for the management of fever and pain but few reports have investigated its antidepressant-like effect. Moreover, the role of the opioidergic pathway has been indicated in depression pathophysiology. This study aimed to examine the involvement of the opioid receptors in the antidepressant-like effect of acetaminophen after acute and sub-chronic administration using mice forced swimming test (FST). Our finding showed that administration of acetaminophen (50 and 100 mg/kg, i.p.) 30 min before the FST produced an antidepressant effect which was reduced by naloxone (1 mg/kg, i.p., a nonselective opioid receptor antagonist). Moreover, we observed that acetaminophen in higher doses (200 and 400 mg/kg) was ineffective. Also, the response of the non-effective dose of acetaminophen (25 mg/kg) was potentiated by the non-effective dose of morphine (0.1 mg/kg) in the FST that was antagonized by naloxone. Also, in contrast to morphine (10 mg/kg), acetaminophen (100 mg/kg, i.p.) induced neither tolerance to the anti-immobility behavior nor withdrawal syndrome after repeated administration. In addition, RT-PCR showed that hippocampal mu- and kappa-opioid receptor mRNA expression increased in mice after repeated administration of acetaminophen; however, morphine therapy for 6 days did not affect kappa-opioid receptor expression. Our findings demonstrated that acetaminophen in lower doses but not high doses revealed an antidepressant-like activity without inducing tolerance and withdrawal syndromes. Moreover, the observed effect of acetaminophen may be via altering the opioid system, particularly hippocampal mu- and kappa-receptors.

Effectiveness and safety of prehospital analgesia with nalbuphine and paracetamol versus morphine by paramedics - an observational study.

BACKGROUND: Despite the development of various analgesic concepts, prehospital oligoanalgesia remains very common. The present work examines prehospital analgesia by paramedics using morphine vs. nalbuphine + paracetamol. METHODS: Patients with out-of-hospital-analgesia performed by paramedics from the emergency medical services of the districts of Fulda (morphine) and Gütersloh (nalbuphine + paracetamol) were evaluated with regards to pain intensity at the beginning and the end of prehospital treatment using the Numeric-Rating-Scale for pain (NRS), sex, age, and complications. The primary endpoint was achievement of adequate analgesia, defined as NRS < 4 at hospital handover, depending on the analgesics administered (nalbuphine + paracetamol vs. morphine). Pain intensity before and after receiving analgesia using the NRS, sex, age and complications were also monitored. RESULTS: A total of 1,808 patients who received out-of-hospital-analgesia were evaluated (nalbuphine + paracetamol: 1,635 (90.4%), NRS-initial: 8.0 ± 1.4, NRS-at-handover: 3.7 ± 2.0; morphine: 173(9.6%), NRS-initial: 8.5 ± 1.1, NRS-at-handover: 5.1 ± 2.0). Factors influencing the difference in NRS were: initial pain intensity on the NRS (regression coefficient (RK): 0.7276, 95%CI: 0.6602-0.7950, p < 0.001), therapy with morphine vs. nalbuphine + paracetamol (RK: -1.2594, 95%CI: -1.5770 - -0.9418, p < 0.001) and traumatic vs. non-traumatic causes of pain (RK: -0.2952, 95%CI: -0.4879 - -0.1024, p = 0.002). Therapy with morphine (n = 34 (19.6%)) compared to nalbuphine + paracetamol (n = 796 (48.7%)) (odds ratio (OR): 0.274, 95%CI: 0.185-0.405, p < 0.001) and the initial NRS score (OR:0.827, 95%CI: 0.771-0.887, p < 0.001) reduced the odds of having an NRS < 4 at hospital handover. Complications occurred with morphine in n = 10 (5.8%) and with nalbuphine + paracetamol in n = 35 (2.1%) cases. Risk factors for complications were analgesia with morphine (OR: 2.690, 95%CI: 1.287-5.621, p = 0.008), female sex (OR: 2.024, 95%CI: 1.040-3.937, p = 0.0379), as well as age (OR: 1.018, 95%CI: 1.003-1.034, p = 0.02). CONCLUSIONS: Compared to morphine, prehospital analgesia with nalbuphine + paracetamol yields favourable effects in terms of analgesic effectiveness and a lower rate of complications and should therefore be considered in future recommendations for prehospital analgesia.

Comparison of the Analgesic Effect of Pericapsular Nerve Group Block and Lumbar Erector Spinae Plane Block in Elective Hip Surgery.

Background and Objectives: The aim of this study was to compare the effectiveness of pericapsular nerve group (PENG) and lumbar erector spinae plane (L-ESP) blocks, both administered with a high volume (40 mL) of local anesthetic (LA), for multimodal postoperative analgesia in patients undergoing hip surgery. Materials and Methods: This was a prospective, double-blind, randomized study that included 75 adult patients who were divided into three equal groups: control, PENG, and L-ESP. The study compared pain intensity, morphine consumption, time to first morphine request, and postoperative satisfaction between the control group, which received standard multimodal analgesia, and the block groups, which received PENG or L-ESP block in addition to multimodal analgesia. The numerical rating scale (NRS) was used to measure pain intensity. Results: The results showed that the block groups had lower pain intensity scores and morphine consumption, a longer time to the first morphine request, and higher postoperative satisfaction compared to the control group. The median maximum NRS score during the first 12 h was four in the control group, two in the PENG group, and three in the L-ESP group. The control group (21.52 ± 9.63 mg) consumed more morphine than the two block groups (PENG, 11.20 ± 7.55 mg; L-ESP, 12.88 ± 8.87 mg) and requested morphine 6.8 h earlier and 5 h earlier than the PENG and L-ESP groups, respectively. The control group (median 3) had the lowest Likert satisfaction scores, while the PENG group (median 4) had the lowest NRS scores (L-ESP, median 4). Conclusions: The application of PENG or L-ESP blocks with high-volume LA in patients undergoing hip surgery reduces the need for postoperative analgesia and improves the quality of multimodal analgesia.

Challenges of acute pain management in older patients.

Adequate management of acute pain in the older population is crucial. However, it is inherently complex because of multiple physiological changes that significantly impact both the pharmacokinetics and pharmacodynamics of medications. Current guidelines promote paracetamol as the first-line analgesic for acute pain in older adults, whereas opioids are advised cautiously for moderate to severe acute pain. However, opioids come with a significant array of side effects, which can be more pronounced in older individuals. Ketamine administered via intranasal (IN) and nebulised inhalation in the emergency department for managing acute pain in older patients shows promising potential for improving pain management and reducing opioid reliance Kampan, Thong-on, Sri-on (2024, Age Ageing, 53, afad255). Nebulised ketamine appears superior in terms of adverse event incidence. However, the adoption of IN or nebulised ketamine in older adult acute pain management remains unclear because of the lack of definitive conclusions and clear guidelines. Nevertheless, these modalities can be valuable options for patients where opioid analgesics are contraindicated or when intravenous morphine titration is impractical or contraindicated. Here, we review these concepts, the latest evidence and propose avenues for research.

Effect of postoperative intermittent boluses of subcostal quadratus lumborum block on pulmonary function recovery and analgesia after gastrectomy: a randomized controlled clinical trial.

BACKGROUND: Following the gastrectomy, the reduction in pulmonary function is partly attributed to postoperative pain. Subcostal quadratus lumborum block (QLB) has recently emerged as a promising component in multimodal analgesia. We aimed to assess the impact of intermittent boluses of subcostal QLB on pulmonary function recovery and analgesic efficacy after gastrectomy. METHODS: Sixty patients scheduled for gastrectomy were randomly assigned to either control group (multimodal analgesia) or intervention group (intermittent boluses of subcostal QLB plus multimodal analgesia). Two primary outcomes included the preservation of forced expiratory volume in the first second (FEV1) and the pain scores (0-10 cm visual analog score) on coughing 24 h postoperatively. We assessed the pulmonary function parameters, pain score, morphine consumption and number of rescue analgesia at a 24-h interval up to 72 h (Day1, Day2, Day3 respectively) as secondary outcomes. RESULTS: 59 patients were analyzed in a modified intention-to-treat set. The preservation of FEV1 (median difference: 4.0%, 97.5% CI: -5.7 to 14.9, P = 0.332) and pain scores on coughing (mean difference: 0.0 cm, 97.5% CI: -1.1 to 1.2, P = 0.924) did not differ significantly between two groups. In the intervention group, the recovery of forced vital capacity (FVC) was faster 72 h after surgery (interaction effect of group*(Day3-Day0): estimated effect (ß) =0.30 L, standard error (SE) =0.13, P = 0.025), pain scores at rest were lower in the first 3 days (interaction effect of group*(Day1-Day0): ß = - 0.8 cm, SE = 0.4, P = 0.035; interaction effect of group*(Day2-Day0): ß = - 1.0 cm, SE = 0.4, P = 0.014; and interaction effect of group*(Day3-Day0): ß = - 1.0 cm, SE = 0.4, P values = 0.009 respectively), intravenous morphine consumption was lower during 0-24 h (median difference: -3 mg, 95% CI -6 to -1, P = 0.014) and in total 72 h (median difference: -5 mg, 95% CI -10 to -1, P = 0.019), and the numbers of rescue analgesia was fewer during 24-48 h (median difference: 0, 95% CI 0 to 0, P = 0.043). Other outcomes didn't show statistical differences. CONCLUSION: Postoperative intermittent boluses of subcostal QLB did not confer advantages in terms of the preservation of FEV1 or pain scores on coughing 24 h after gastrectomy. However, notable effects were observed in analgesia at rest and FVC recovery.

Commonly used antiemetics for prophylaxis of postoperative nausea and vomiting after Caesarean delivery with neuraxial morphine: a network meta-analysis.

BACKGROUND: Dopamine antagonists, 5-HT3 antagonists, and dexamethasone are frequently used in obstetrics to prevent postoperative nausea and vomiting (PONV). However, the superiority of any drug class is yet to be established. This network meta-analysis aimed to compare the efficacy of these antiemetics for PONV prophylaxis in women receiving neuraxial morphine for Caesarean delivery. METHODS: We searched PubMed, Embase, CENTRAL, Web of Science, and Wanfang Data for eligible randomised controlled trials. Primary outcomes were the incidences of postoperative nausea (PON) and postoperative vomiting (POV) within 24 h after surgery. We used a Bayesian random-effects model and calculated odds ratios with 95% credible intervals for dichotomous data. We performed sensitivity and subgroup analyses for primary outcomes. RESULTS: A total of 33 studies with 4238 women were included. In the primary analyses of all women, 5-HT3 antagonists, dopamine antagonists, dexamethasone, and 5-HT3 antagonists plus dexamethasone significantly reduced PON and POV compared with placebo, and 5-HT3 antagonists plus dexamethasone were more effective than monotherapy. In the subgroup analyses, similar results were seen in women receiving epidural morphine or intrathecal morphine alone but not in women receiving intrathecal morphine with fentanyl or sufentanil. However, most included studies had some concerns or a high risk of bias, and the overall certainty of the evidence was low or very low. CONCLUSIONS: Combined 5-HT3 antagonists plus dexamethasone are more effective than monotherapy in preventing PONV associated with neuraxial morphine after Caesarean delivery. Future studies are needed to determine the role of prophylactic antiemetics in women receiving intrathecal morphine and lipophilic opioids. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42023454602.

Intravenous administration of recombinant Phα1ß: Antinociceptive properties and morphine tolerance reversal in a cancer-associated pain model.

Cancer-related pain is considered one of the most prevalent symptoms for those affected by cancer, significantly influencing quality of life and treatment outcomes. Morphine is currently employed for analgesic treatment in this case, however, chronic use of this opioid is limited by the development of analgesic tolerance and adverse effects, such as digestive and neurological disorders. Alternative therapies, such as ion channel blockade, are explored. The toxin Phα1ß has demonstrated efficacy in blocking calcium channels, making it a potential candidate for alleviating cancer-related pain. This study aims to assess the antinociceptive effects resulting from intravenous administration of the recombinant form of Phα1ß (r-Phα1ß) in an experimental model of cancer-related pain in mice, tolerant or not to morphine. The model of cancer-induced pain was used to evaluate these effects, with the injection of B16F10 cells, followed by the administration of the r-Phα1ß, and evaluation of the mechanical threshold by the von Frey test. Also, adverse effects were assessed using a score scale, the rotarod, and open field tests. Results indicate that the administration of r-Phα1ß provoked antinociception in animals with cancer-induced mechanical hyperalgesia, with or without morphine tolerance. Previous administration of r-Phα1ß was able to recover the analgesic activity of morphine in animals tolerant to this opioid. r-Phα1ß was proved safe for these parameters, as no adverse effects related to motor and behavioral activity were observed following intravenous administration. This study suggests that the concomitant use of morphine and r-Phα1ß could be a viable strategy for pain modulation in cancer patients.

Intermittent intravenous paracetamol versus continuous morphine in infants undergoing cardiothoracic surgery: a multi-center randomized controlled trial.

BACKGROUND: To determine whether intermittent intravenous (IV) paracetamol as primary analgesic would significantly reduce morphine consumption in children aged 0-3 years after cardiac surgery with cardiopulmonary bypass. METHODS: Multi-center, randomized, double-blinded, controlled trial in four level-3 Pediatric Intensive Care Units (PICU) in the Netherlands and Belgium. Inclusion period; March 2016-July 2020. Children aged 0-3 years, undergoing cardiac surgery with cardiopulmonary bypass were eligible. Patients were randomized to continuous morphine or intermittent IV paracetamol as primary analgesic after a loading dose of 100 mcg/kg morphine was administered at the end of surgery. Rescue morphine was given if numeric rating scale (NRS) pain scores exceeded predetermined cutoff values. Primary outcome was median weight-adjusted cumulative morphine dose in mcg/kg in the first 48 h postoperative. For the comparison of the primary outcome between groups, the nonparametric Van Elteren test with stratification by center was used. For comparison of the proportion of patients with one or more NRS pain scores of 4 and higher between the two groups, a non-inferiority analysis was performed using a non-inferiority margin of 20%. RESULTS: In total, 828 were screened and finally 208 patients were included; parents of 315 patients did not give consent and 305 were excluded for various reasons. Fourteen of the enrolled 208 children were withdrawn from the study before start of study medication leaving 194 patients for final analysis. One hundred and two patients received intermittent IV paracetamol, 106 received continuous morphine. The median weight-adjusted cumulative morphine consumption in the first 48 h postoperative in the IV paracetamol group was 5 times lower (79%) than that in the morphine group (median, 145.0 (IQR, 115.0-432.5) mcg/kg vs 692.6 (IQR, 532.7-856.1) mcg/kg; P < 0.001). The rescue morphine consumption was similar between the groups (p = 0.38). Non-inferiority of IV paracetamol administration in terms of NRS pain scores was proven; difference in proportion - 3.1% (95% CI - 16.6-10.3%). CONCLUSIONS: In children aged 0-3 years undergoing cardiac surgery, use of intermittent IV paracetamol reduces the median weight-adjusted cumulative morphine consumption in the first 48 h after surgery by 79% with equal pain relief showing equipoise for IV paracetamol as primary analgesic. Trial Registration Clinicaltrials.gov, Identifier: NCT05853263; EudraCT Number: 2015-001835-20.

Evaluation of neuraxial analgesia on outcomes for patients undergoing robot assisted abdominal surgery.

STUDY OBJECTIVE: Following robot assisted abdominal surgery, the pain can be moderate in severity. Neuraxial analgesia may decrease the activity of the detrusor muscle, reduce the incidence of bladder spasm and provide effective somatic and visceral analgesia. In this systematic review, we assessed the role of neuraxial analgesia in robot assisted abdominal surgery. DESIGN: Systematic review. SETTINGS: Robot assisted abdominal surgery. PATIENTS: Adults. INTERVENTIONS: Subsequent to a search of the electronic databases, observational studies and randomized controlled trials that assessed the effect of neuraxial analgesia instituted at induction of anesthesia or intraoperatively in adult and robot assisted abdominal surgery were considered for inclusion. The outcomes of observational studies as well as randomized controlled trials which were not subjected to meta-analysis were presented in descriptive terms. Meta-analysis was conducted if an outcome of interest was reported by two or more randomized controlled trials. MAIN RESULTS: We included 19 and 11 studies that investigated spinal and epidural analgesia in adults, respectively. The coprimary outcomes were the pain score at rest at 24 h and the cumulative intravenous morphine consumption at 24 h. Spinal analgesia with long acting neuraxial opioid did not decrease the pain score at rest at 24 h although it reduced the cumulative intravenous morphine consumption at 24 h by a mean difference (95%CI) of 14.88 mg (-22.13--7.63; p < 0.0001, I2 = 50%) with a low and moderate quality of evidence, respectively, on meta-analysis of randomized controlled trials. Spinal analgesia with long acting neuraxial opioid had a beneficial effect on analgesic indices till the second postoperative day and a positive influence on opioid consumption up to and including the 72 h time point. The majority of studies demonstrated the use of spinal analgesia with long acting neuraxial opioid to lead to no difference in the incidence of postoperative nausea and vomiting, and the occurrence of pruritus was found to be increased with spinal analgesia with long acting neuraxial opioid in recovery but not at later time points. No difference was revealed in the incidence of urinary retention. The evidence in regard to the quality of recovery-15 score at 24 h and hospital length of stay was not fully consistent, although most studies indicated no difference between spinal analgesia and control for these outcomes. Epidural analgesia in robot assisted abdominal surgery was shown to decrease the pain on movement at 12 h but it had not been studied with respect to its influence on the pain score at rest at 24 h or the cumulative intravenous morphine consumption at 24 h. It did not reduce the pain on movement at later time points and the evidence related to the hospital length of stay was inconsistent. CONCLUSIONS: Spinal analgesia with long acting neuraxial opioid had a favourable effect on analgesic indices and opioid consumption, and is recommended by the authors, but the evidence for spinal analgesia with short acting neuraxial opioid and epidural analgesia was limited.

Research Note: Morphine influences circulating and tissue concentrations of met-enkephalin and proenkephalin (PENK) expression and plasma concentrations of corticosterone in chickens.

The effects of the administration of the opioid agonist, morphine, on plasma and tissue concentrations of Met-enkephalin were determined in 14 wk old female chickens. In addition, effects of morphine on proenkephalin (PENK) expression were examined. Plasma concentrations of Met-enkephalin were reduced 10 minutes after morphine administration. Plasma concentrations of peptides that contain Met-enkephalin motifs were decreased 30 minutes after morphine administration. Tissue concentrations of Met-enkephalin tended to be depressed following morphine administration. Adrenal concentrations of PENK peptides containing Met-enkephalin motifs were decreased in chickens challenged with morphine. Expression of PENK in the anterior pituitary gland and adrenal glands were decreased in morphine treated compared to control pullets. In contrast, plasma concentrations of corticosterone were elevated 10 min after morphine treatment. Morphine also induced changes in mu (µ) opioid receptors and delta (δ) opioid receptors in both anterior pituitary tissue and adrenal tissues.

Model of negative affect induced by withdrawal from acute and chronic morphine administration in male mice.

Opioid use disorder (OUD) is a chronic relapsing disorder that is a major burden for the lives of affected individuals, and society as a whole. Opioid withdrawal is characterized by strong physical symptoms, along with signs of negative affect. Negative affect due to opioid withdrawal is a major obstacle to recovery and relapse prevention. The mechanisms behind negative affect due to either spontaneous or antagonist-precipitated opioid withdrawal are not well known, and more animal models need be developed. Here, we present behavioral models of negative affect upon naloxone-precipitated morphine withdrawal in adult male mice. Social, anxiety, and despair-like deficits were investigated following naloxone administration in mice receiving morphine under three dosing regimens; acute, chronic constant dose and chronic escalating doses. Social behaviour in the three-chamber social preference test was decreased following withdrawal from chronic and escalating but not acute morphine. Anxiety-like behaviour in the open field was increased for all three treatments. Despair-like behaviour was increased following withdrawal from chronic and escalating but not acute morphine. Altogether, these animal models will contribute to study behavioural and neuronal circuitries involved in the several negative affective signs characterizing OUD.

Preoperative Intrathecal Morphine is Associated With Reduced Postoperative Pain, Agitation, and Delirium In Living Donor Kidney Transplantation Recipients.

BACKGROUND: Postoperative delirium after organ transplantation can lead to increased length of hospital stay and mortality. Because pain is an important risk factor for delirium, perioperative analgesia with intrathecal morphine (ITM) may mitigate postoperative delirium development. We evaluated if ITM reduces postoperative delirium incidence in living donor kidney transplant (LDKT) recipients. METHODS: Two hundred ninety-six patients who received LDKT between 2014 and 2018 at our hospital were retrospectively analyzed. Recipients who received preoperative ITM (ITM group) were compared with those who did not (control group). The primary outcome was postoperative delirium based on the Confusion Assessment Method for Intensive Care Unit results during the first 4 postoperative days. RESULTS: Delirium occurred in 2.6% (4/154) and 7.0% (10/142) of the ITM and control groups, respectively. Multivariable analysis showed age (odds ratio [OR]: 1.07, 95% CI: 1.01-1.14; P = .031), recent smoking (OR: 7.87, 95% CI: 1.43-43.31; P = .018), preoperative psychotropics (OR: 23.01, 95% CI: 3.22-164.66; P = .002) were risk factors, whereas ITM was a protective factor (OR: 0.23, 95% CI: 0.06-0.89; P = .033). CONCLUSIONS: Preoperative ITM showed an independent association with reduced post-LDKT delirium. Further studies and the development of regional analgesia for delirium prevention may enhance the postoperative recovery of transplant recipients.