Acute Pain Management in Emergency Department, Low Dose Ketamine Versus Morphine, A Randomized Clinical Trial

A systematic review and meta-analysis comparing the efficacy and safety of ketamine versus morphine for the treatment of acute pain

INTRODUCTION

Ketamine is reported as a potent opioid alternative that provides significant reduction in pain with no severe adverse events. However, some studies didn't find its use satisfactory and reported less reduction in pain score with ketamine. The purpose of this study is to compare the efficacy and safety of ketamine versus morphine for the treatment of acute pain in emergency situations.

EVIDENCE ACQUISITION

The PubMed, MEDLINE, PsycINFO EMBASE, Cochrane Library, PROSPERO registry platform, and ClinicalTrials.gov websites were queried in accordance with the PRISMA guidelines in order to locate relevant studies. According to the predefined PICOS criteria, articles were included and event data pertaining to changes in Visual Analog Scale or Numeric Rating Scale pain scales were extracted. Using RevMan and MedCalc, a meta-analysis was conducted to compare the effects of ketamine and morphine for the treatment of acute pain.

EVIDENCE SYNTHESIS

Twelve studies met the criteria for inclusion in this meta-analysis. Ketamine was found to be more effective than morphine at reducing pain scores, with an odds ratio of 0.60 (95% CI 0.48 to 0.76). Similarly, no severe adverse events related to ketamine were reported in any study, and it has a low-risk ratio of 0.78 (95% CI 0.70 to 0.87). Egger's Test P values (0.3052) and Begg's Test P values (0.3869) indicate a low risk of bias, and the Bland-Altman plot demonstrates a high degree of concordance.

CONCLUSIONS

Ketamine is a potent and effective alternative to morphine for the management of acute pain, and it reduces pain score significantly with minimal side effects.

Continued Opioid Use and Adverse Events Following Provision of Opioids for Musculoskeletal Pain in the Emergency Department: A Systematic Review and Meta-Analysis

BACKGROUND

The prevalence of continued opioid use or serious adverse events (SAEs) following opioid therapy in the emergency department (ED) for musculoskeletal pain is unclear. The aim of this review was to examine the prevalence of continued opioid use and serious adverse events (SAEs) following the provision of opioids for musculoskeletal pain in the emergency department (ED) or at discharge.

METHODS

Records were searched from MEDLINE, EMBASE and CINAHL from inception to 7 October 2022. We included randomised controlled trials and observational studies enrolling adult patients with musculoskeletal pain who were administered and/or prescribed opioids in the ED. Continued opioid use and opioid misuse data after day 4 since ED discharge were extracted. Adverse events were coded using the Common Terminology Criteria for Adverse Events (CTCAE), and those rated as grades 3-4 (severe or life-threatening) and grade 5 (death) were considered SAEs. Risk of bias was assessed using the Quality in Prognosis Studies (QUIPS) tool.

RESULTS

Seventy-two studies were included. Among opioid-naïve patients who received an opioid prescription, 6.8-7.0% reported recent opioid use at 3-12 months after discharge, 4.4% filled ≥ 5 opioid prescriptions and 3.1% filled > 90-day supply of opioids within 6 months. The prevalence of SAEs was 0.02% [95% confidence interval (CI) 0, 0.2%] in the ED and 0.1% (95% CI 0, 1.5%) within 2 days. One study observed 42.9% of patients misused opioids within 30 days after discharge.

CONCLUSIONS

Around 7% of opioid-naïve patients with musculoskeletal pain receiving opioid therapy continue opioid use at 3-12 months after ED discharge. SAEs following ED administration of an opioid were uncommon; however, studies only monitored patients for 2 days.

PROTOCOL REGISTRATION

10.31219/osf.io/w4z3u.

The Effectiveness of Ketamine Versus Opioids in Patients With Acute Pain in the Emergency Department: A Systematic Review and Meta-Analysis

Opioids are the mainstay of treatment for acute pain in the emergency department. However, its misuse led to the investigation of alternative effective analgesic options for acute pain complaints such as ketamine. Therefore, this systematic review and meta-analysis aimed to determine the effectiveness of ketamine in comparison to opioids in the management of acute pain. This was a systematic review and meta-analysis of randomized controlled trials comparing ketamine to opioids for the relief of acute pain in the ED. Eligible studies were identified by searching the following electronic databases: Medline, Embase, and Central. Studies utilizing either the visual analog scale (VAS) or the numeric rating scale (NRS) for pain scoring in ketamine vs opioids were included. The revised Cochrane risk-of-bias tool for randomized trials was utilized. A random-effects model was performed, and all outcomes were pooled by the inverse variance weighting method. The total number of studies that met the criteria of systematic reviews was nine of which seven of them were included in the meta-analysis with 789 participants. The overall effect of NRS trials was the standardized mean difference (SMD) = -0.07, 95% confidence interval (CI) -0.31 to 0.17, P-value = 0.56, I² =85%. While VAS trials showed an overall effect of SMD = -0.02, 95% CI -0.22 to 0.18, P = 0.84, I² = 59%). Moreover, higher adverse events were reported in opioids; however, this was not statistically significant (SMD = 1.23, 95% CI 0.93-1.64, P = 0.15, I2 =38%). Ketamine for immediate pain relief at 15 minutes could be an effective alternative to opioids, but its overall effect in comparison to opioids for improving the pain has not shown a statistically significant difference. There was high heterogeneity in the included studies; thus, a sub-group analysis was performed.

Comparing the Effects of Low-Dose Ketamine, Fentanyl, and Morphine on Hemorrhagic Tolerance and Analgesia in Humans

Hemorrhage is a leading cause of preventable battlefield and civilian trauma deaths. Ketamine, fentanyl, and morphine are recommended analgesics for use in the prehospital (i.e., field) setting to reduce pain. However, it is unknown whether any of these analgesics reduce hemorrhagic tolerance in humans. We tested the hypothesis that fentanyl (75 µg) and morphine (5 mg), but not ketamine (20 mg), would reduce tolerance to simulated hemorrhage in conscious humans. Each of the three analgesics was evaluated independently among different cohorts of healthy adults in a randomized, crossover (within drug/placebo comparison), placebo-controlled fashion using doses derived from the Tactical Combat Casualty Care Guidelines for Medical Personnel. One minute after an intravenous infusion of the analgesic or placebo (saline), we employed a pre-syncopal limited progressive lower-body negative pressure (LBNP) protocol to determine hemorrhagic tolerance. Hemorrhagic tolerance was quantified as a cumulative stress index (CSI), which is the sum of products of the LBNP and the duration (e.g., [40 mmHg x 3 min] + [50 mmHg x 3 min] …). Compared with ketamine (p = 0.002 post hoc result) and fentanyl (p = 0.02 post hoc result), morphine reduced the CSI (ketamine (n = 30): 99 [73-139], fentanyl (n = 28): 95 [68-130], morphine (n = 30): 62 [35-85]; values expressed as a % of the respective placebo trial's CSI; median [IQR]; Kruskal-Wallis test p = 0.002). Morphine-induced reductions in tolerance to central hypovolemia were not well explained by a prediction model including biological sex, body mass, and age (R2=0.05, p = 0.74). These experimental data demonstrate that morphine reduces tolerance to simulated hemorrhage while fentanyl and ketamine do not affect tolerance. Thus, these laboratory-based data, captured via simulated hemorrhage, suggest that morphine should not be used for a hemorrhaging individual in the prehospital setting.

Effectiveness of Opioid Analgesic Medicines Prescribed in or at Discharge From Emergency Departments for Musculoskeletal Pain : A Systematic Review and Meta-analysis

BACKGROUND

The comparative benefits and harms of opioids for musculoskeletal pain in the emergency department (ED) are uncertain.

PURPOSE

To evaluate the comparative effectiveness and harms of opioids for musculoskeletal pain in the ED setting.

DATA SOURCES

Electronic databases and registries from inception to 7 February 2022.

STUDY SELECTION

Randomized controlled trials of any opioid analgesic compared with placebo or a nonopioid analgesic administered or prescribed to adults in or on discharge from the ED.

DATA EXTRACTION

Pain and disability were rated on a scale of 0 to 100 and pooled using a random-effects model. Certainty of evidence was assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework.

DATA SYNTHESIS

Forty-two articles were included (n = 6128). In the ED, opioids were statistically but not clinically more effective in reducing pain in the short term (about 2 hours) than placebo and paracetamol (acetaminophen) but were not clinically or statistically more effective than nonsteroidal anti-inflammatory drugs (NSAIDs) or local or systemic anesthetics. Opioids may carry higher risk for harms than placebo, paracetamol, or NSAIDs, although evidence is very uncertain. There was no evidence of difference in harms associated with local or systemic anesthetics.

LIMITATIONS

Low or very low GRADE ratings for some outcomes, unexplained heterogeneity, and little information on long-term outcomes.

CONCLUSION

The risk-benefit balance of opioids versus placebo, paracetamol, NSAIDs, and local or systemic anesthetics is uncertain. Opioids may have equivalent pain outcomes compared with NSAIDs, but evidence on comparisons of harms is very uncertain and heterogeneous. Although factors such as route of administration or dosage may explain some heterogeneity, more work is needed to identify which subgroups will have a more favorable benefit-risk balance for one analgesic over another. Longer-term pain management once dose thresholds are reached is also uncertain.

PRIMARY FUNDING SOURCE

None. (PROSPERO: CRD42021275293).

Low-dose morphine reduces tolerance to central hypovolemia in healthy adults without affecting muscle sympathetic outflow

Hemorrhage is a leading cause of preventable battlefield and civilian trauma deaths. Low-dose (i.e., an analgesic dose) morphine is recommended for use in the prehospital (i.e., field) setting. Morphine administration reduces hemorrhagic tolerance in rodents. However, it is unknown whether morphine impairs autonomic cardiovascular regulation and consequently reduces hemorrhagic tolerance in humans. Thus, the purpose of this study was to test the hypothesis that low-dose morphine reduces hemorrhagic tolerance in conscious humans. Thirty adults (15 women/15 men; 29 ± 6 yr; 26 ± 4 kg·m-2, means ± SD) completed this randomized, crossover, double-blinded, placebo-controlled trial. One minute after intravenous administration of morphine (5 mg) or placebo (saline), we used a presyncopal limited progressive lower-body negative pressure (LBNP) protocol to determine hemorrhagic tolerance. Hemorrhagic tolerance was quantified as a cumulative stress index (mmHg·min), which was compared between trials using a Wilcoxon matched-pairs signed-rank test. We also compared muscle sympathetic nerve activity (MSNA; microneurography) and beat-to-beat blood pressure (photoplethysmography) during the LBNP test using mixed-effects analyses [time (LBNP stage) × trial]. Median LBNP tolerance was lower during morphine trials (placebo: 692 [473-997] vs. morphine: 385 [251-728] mmHg·min, P < 0.001, CI: -394 to -128). Systolic blood pressure was 8 mmHg lower during moderate central hypovolemia during morphine trials (post hoc P = 0.02; time: P < 0.001, trial: P = 0.13, interaction: P = 0.006). MSNA burst frequency responses were not different between trials (time: P < 0.001, trial: P = 0.80, interaction: P = 0.51). These data demonstrate that low-dose morphine reduces hemorrhagic tolerance in conscious humans. Thus, morphine is not an ideal analgesic for a hemorrhaging individual in the prehospital setting.NEW & NOTEWORTHY In this randomized, crossover, placebo-controlled trial, we found that tolerance to simulated hemorrhage was lower after low-dose morphine administration. Such reductions in hemorrhagic tolerance were observed without differences in MSNA burst frequency responses between morphine and placebo trials. These data, the first to be obtained in conscious humans, demonstrate that low-dose morphine reduces hemorrhagic tolerance. Thus, morphine is not an ideal analgesic for a hemorrhaging individual in the prehospital setting.

Low-Dose Morphine Reduces Pain Perception and Blood Pressure, but Not Muscle Sympathetic Outflow, Responses During the Cold Pressor Test

Our knowledge about how low-dose (analgesic) morphine affects autonomic cardiovascular regulation is primarily limited to animal experiments. Notably, it is unknown if low-dose morphine affects human autonomic cardiovascular responses during painful stimuli in conscious humans. Therefore, we tested the hypothesis that low-dose morphine reduces perceived pain and subsequent sympathetic and cardiovascular responses in humans during an experimental noxious stimulus. Twenty-nine participants (14F/15M; 29±6 y; 26±4 kg•m^-2, mean ± SD) completed this randomized, crossover, placebo-controlled trial during two laboratory visits. During each visit, participants completed a cold pressor test (CPT; hand in ~0.4 °C ice bath for two minutes) before and ~35 minutes after drug/placebo administration (5 mg IV morphine or saline). We compared pain perception (100 mm visual analog scale), muscle sympathetic nerve activity (MSNA; microneurography; 14 paired recordings), and beat-to-beat blood pressure (BP; photoplethysmography) between trials (at both pre- and post-drug/placebo time points) using paired, two-tailed t-tests. Before drug/placebo infusion, perceived pain (p=0.92), Δ MSNA burst frequency (n=14, p=0.21), and Δ mean BP (p=0.39) during the CPT were not different between trials. After the drug/placebo infusion, morphine versus placebo attenuated perceived pain (morphine: 43±20 vs. placebo: 57±24 mm,p<0.001) and Δ mean BP (morphine: 10±7 vs. placebo: 13±8 mmHg,p=0.003), but not Δ MSNA burst frequency (morphine: 10±11 vs. placebo: 13±11 bursts/minute,p=0.12), during the CPT. Reductions in pain perception and Δ mean BP were only weakly related (r=0.34,p=0.07; post-morphine CPT minus post-placebo CPT). These data provide valuable information regarding how low-dose morphine affects autonomic cardiovascular responses during an experimental painful stimulus.

Interactions between Ketamine and Magnesium for the Treatment of Pain: Current State of the Art

BACKGROUND

Over the past three decades, NMDA-receptor antagonists have been shown to be efficient drugs for treating pain, particularly pain resistant to conventional analgesics. Emphasis will be on the old-new drugs, ketamine and magnesium, and their combination as a novel approach for treating chronic pain.

METHODS

The MEDLINE database was searched via PubMed for articles that were published up to March 1, 2020, with the keywords 'ketamine', 'magnesium', and 'pain' (in the title/abstract).

RESULTS

Studies in animals, as well as humans, have shown that interactions of ketamine and magnesium can be additive, antagonistic, and synergistic. These discrepancies might be due to differences in magnesium and ketamine dosage, administration times, and the chronological order of drug administration. Different kinds of pain can also be the source of divergent results.

CONCLUSION

This review explains why studies performed with a combination of ketamine and magnesium have given inconsistent results. Because of the lack of efficacy of drugs available for pain, ketamine and magnesium in combination provide a novel therapeutic approach that needs to be standardized with a suitable dosing regimen, including the chronological order of drug administration.

Comparison of the efficacy of intranasal ketamine versus intravenous ketorolac on acute non-traumatic headaches: a randomized double-blind clinical trial

INTRODUCTION

Non - traumatic headaches are one of the most common causes of referral to hospital emergency. This study aimed to compare the efficacy of intranasal ketamine and intravenous ketorolac on acute non-traumatic headaches.

METHODS

This randomized and double-blind clinical trial was conducted in 2019. One hundred and forty samples were randomly divided into intranasal ketamine (A) and intravenous ketorolac (B). Group (A) received ketamine intranasal (0.75 mg/kg, max 75 mg), and group B received intravenous ketorolac (30 mg). Headache severity was measured on arrival, 30, 60, and 120 min after intervention with Visual Analogue Scale (VAS). The side effects were recorded an hour after the intervention.

RESULT

The mean difference of pain intensity 30, 60, and 120 min after the intervention between the two groups was statistically significant (p < 0.001). In the first 30 min, significant changes were observed in the VAS levels of the two groups. These changes were significantly greater in the intranasal ketamine group (p < 0.001). Side effects such as fatigue, dizziness, general discomfort, nausea, increased heart rate, and hypertension were significantly higher in the ketamine group (p < 0.05).

CONCLUSION

Intranasal ketamine and intravenous ketorolac both effectively reduced headaches. However, more analgesic effects of intranasal ketamine in a short time can be considered as a selective approach to reducing headaches.

TRIAL REGISTRATION

IRCT20180108038276N3 , Registered 29 September 2019.

ETHICS COMMITTEE REFERENCE NUMBER

IR.KUMS.REC.1398.068.

A Comparison of Tertiary Drug Resources' Consistency Regarding Drug-Drug Interactions of Adjunctive Analgesics

Background: Health care providers routinely rely on tertiary drug information resources to affirm knowledge or proactively verify the safety and efficacy of medications. Though all patient care areas are affected, the reliability of these resources is perhaps nowhere as poignant as it is in high-acuity settings, including the emergency department and the intensive care unit. As providers seek to identify adjunctive analgesics for acute pain in these areas, they must be able to rely on the integrity to whichever resource their institution has granted access. Objective: To determine the congruency of drug-drug interaction information found on 3 tertiary drug resources. Methods: A drug-drug interaction analysis was conducted on Micromedex, Lexicomp, and Medscape. Adjunctive analgesics included dexmedetomidine and ketamine, which were compared with the intravenous opioid products morphine, fentanyl, and hydromorphone. Results: Significant discrepancies were appreciated with regard to the severity of drug-drug interactions. In addition, the heterogeneity in which reaction severity and likelihood are described by each respective resource makes direct comparisons difficult. Interaction warnings for dexmedetomidine and fentanyl included a "major interaction" from Micromedex, whereas Lexicomp did not identify a risk and Medscape only recommended increased monitoring on the grounds of respiratory and central nervous system depression. Conclusions: Health care providers must remain vigilant when reviewing tertiary drug information resources. Pharmacists possess the training and skills necessary to assist interdisciplinary medical teams in providing optimal patient care through evaluating and applying the information gleaned from these resources.

Melatonin Blocks Morphine-Induced Place Preference: Involvement of GLT-1, NF-κB, BDNF, and CREB in the Nucleus Accumbens

Opioid addiction remains a widespread issue despite continuous attempts by the FDA to help maintain abstinence. Melatonin is a neurohormone considered to be involved only in the neuroendocrine and reproductive systems; however, recent reports have demonstrated its potential to attenuate drug addiction and dependence. Cumulative studies have suggested that melatonin can attenuate the rewarding effects of several drugs of abuse, including opioids. This study aimed to investigate the effect of melatonin (50 mg/kg) on morphine (5 mg/kg) to produce place preference. We also investigated the effect of melatonin and morphine on the expression of GLT-1, BDNF, NF-κB, and CREB within the nucleus accumbens. Male Wistar rats were divided into control, morphine, melatonin, and the morphine + melatonin groups. The study involved a two-phase habituation phase from day 1 to day 3 and an acquisition phase from day 5 to day 14. The conditioned place preference (CPP) score, distance traveled, resting time, ambulatory count, and total activity count were measured for all animals. Rats that received morphine showed a significant increase in CPP score compared to those in the control group. Morphine treatment reduced the mRNA expression of GLT-1, BDNF, and CREB and increased that of NF-κB. However, melatonin treatment administered 30 min before morphine treatment attenuated morphine place preference and reversed GLT-1, BDNF, NF-κB, and CREB expression levels. In conclusion, the study results indicate, for the first time, the new potential targets of melatonin in modulating morphine-induced CPP.

Low-Dose Ketamine Infusion Versus Morphine Infusion During Abdominoplasty to Change the Postoperative Pain Profile

BACKGROUND

With the increased number of abdominoplasty all over the world, and the need to manage postoperative pain, it is a must to find proper and effective drugs to decrease opioid consumption in the postoperative period.

OBJECTIVES

In this double-blind randomized controlled clinical trial, we assumed that low-dose ketamine infusion will reduce the postoperative pain profile than the conventional method of morphine.

METHODS

The scheduled patients for abdominoplasty under general anesthesia were recruited in two groups: group (K) with low-dose ketamine infusion intra-operatively (80 patients) and group (M) with morphine infusion intra-operatively (80 patients). Both groups were monitored intraoperatively and postoperatively for rescue doses of fentanyl, visual analogue scale (VAS), and side effects.

RESULTS

There were no statistical differences between both groups regarding the fentanyl rescue doses intra- and postoperative with no remarkable side effects.

CONCLUSIONS

Low-dose ketamine has a useful analgesic effect in abdominoplasty similar to morphine without remarkable side effects, such as sedation or hallucinations.

Comparative Effectiveness of Analgesics to Reduce Acute Pain in the Prehospital Setting

Objectives: The objectives of this study were to assess comparative effectiveness and harms of opioid and nonopioid analgesics for the treatment of moderate to severe acute pain in the prehospital setting. Methods: We searched MEDLINE^®, Embase^®, and Cochrane Central from the earliest date through May 9, 2019. Two investigators screened abstracts, reviewed full-text files, abstracted data, and assessed study level risk of bias. We performed meta-analyses when appropriate. Conclusions were made with consideration of established clinically important differences and we graded each conclusion's strength of evidence (SOE). Results: We included 52 randomized controlled trials and 13 observational studies. Due to the absence or insufficiency of prehospital evidence we based conclusions for initial analgesia on indirect evidence from the emergency department setting. As initial analgesics, there is no evidence of a clinically important difference in the change of pain scores with opioids vs. ketamine administered primarily intravenously (IV) (low SOE), IV acetaminophen (APAP) (low SOE), or nonsteroidal anti-inflammatory drugs (NSAIDs) administered primarily IV (moderate SOE). The combined use of an opioid and ketamine, administered primarily IV, may reduce pain more than an opioid alone at 15 and 30 minutes (low SOE). Opioids may cause fewer adverse events than ketamine (low SOE) when primarily administered intranasally. Opioids cause less dizziness than ketamine (low SOE) but may increase the risk of respiratory depression compared with ketamine (low SOE), primarily administered IV. Opioids cause more dizziness (moderate SOE) and may cause more adverse events than APAP (low SOE), both administered IV, but there is no evidence of a clinically important difference in hypotension (low SOE). Opioids may cause more adverse events and more drowsiness than NSAIDs (low SOE), both administered primarily IV. Conclusions: As initial analgesia, opioids are no different than ketamine, APAP, and NSAIDs in reducing acute pain in the prehospital setting. Opioids may cause fewer total side effects than ketamine, but more than APAP or NSAIDs. Combining an opioid and ketamine may reduce acute pain more than an opioid alone but comparative harms are uncertain. When initial morphine is inadequate, giving ketamine may provide greater and quicker acute pain relief than giving additional morphine, although comparative harms are uncertain. Due to indirectness, strength of evidence is generally low, and future research in the prehospital setting is needed.

Assessment of Acute Pain Management and Associated Factors among Emergency Surgical Patients in Gondar University Specialized Hospital Emergency Department, Northwest Ethiopia, 2018: Institutional Based Cross-Sectional Study

Background

Adequate pain management has led to increased comfort in emergency patients, reducing morbidity and improving long term outcomes. Different pain management modalities have been applied in the emergency department among which systemic analgesia is commonly used by preceding a nerve block. Several factors have been associated with poor pain management in low resource setting areas. We aimed to determine pain management modalities and associated factors among emergency surgical patients.

Patients and Methods

After obtaining ethical approval from Ethical Review Committee, 203 volunteer patients were enrolled. Institutional based cross-sectional prospective study was conducted from April to May 2018 in Gondar University Specialized Hospital Emergency Department. The severity of pain was measured through Numerical Rating Scale and statistical analysis was performed using SPSS statistical package version 23. Descriptive statistics cross-tab and binary logistics were performed to identify factors related to pain management in emergency department.

Results

A total of 203 patients, 138 (68%) males and 65 (32%) females with response rate of 94%, participated in this study. Among them, 66% patients received analgesia within two hours of ED presentation with a mean ± SD of 61.0 ± 34.1 minutes. 70.4 % of patients complained of moderate and severe pain after receiving analgesia. There was a significant difference between trauma and nontrauma patients in mean time of analgesia receiving and residual pain severity (p < 0.001). Age, trauma, physician pain assessment, and severity of pain were the predicting factors for analgesia delivery.

Conclusion

The overall practice of pain management in Gondar University Specialized Hospital Emergency Department was not adequate. Therefore, it is vital to implement an objective pain assessment method and documentation of the pain severity to improve pain management practice.