Comparison of patient-controlled epidural analgesia and epidural morphine for post-cesarean section analgesia: experience from a tertiary center in China.

PURPOSE: To compare patient-controlled epidural analgesia (PCEA) and epidural morphine (EM) for post-cesarean section analgesia in real-world experience from China. METHODS: Parturients receiving one dose of EM (1-2 mg), PCEA, or both EM and PCEA from Peking Union Medical College Hospital were retrospectively recruited. Logistic models were used to identify risk factors. RESULTS: Of 1079 parturients enrolled, 919 (85.2%) parturients received only EM, 105 (9.7%) parturients received PCEA, and 55 (5.1%) parturients received both EM and PCEA. Significantly more parturients from EM group requested supplementary analgesia than those from PCEA and PCEA + EM group (583, 63.4% vs 52, 49.5% vs 25, 45.5%, P = 0.001) with more times of supplementary analgesia (1, IQR: 0-2 vs 0, IQR: 0-1 vs 0, IQR: 0-1 times, P < 0.001) and larger amounts of nonsteroidal anti-inflammatory drugs (NSAIDs) (50, IQR: 0-100 mg vs 0, IQR: 0-50 mg vs 0, IQR: 0-50 mg, P < 0.001). In multivariable Logistic regression for the supplementary analgesia risk, the application of PCEA (OR: 0.557, 95%CI 0.396-0.783, P = 0.001) and the use of NSAIDs intraoperatively (OR: 2.996, 95%CI 1.811-4.957, P < 0.001) were identified as independent predictors. A total of 1040 (96.4%) patients received prophylactic antiemetic therapy during surgery. Only 13 (1.2%) and 7 (0.6%) patients in our cohort requested antiemetic and antipruritic drugs, respectively. CONCLUSION: The use of PCEA was an independent protective factor for supplementary analgesia during the post-cesarean section. Prophylactic antiemetic therapy may reduce the side effects of post-cesarean analgesia.

Efficacy and Safety of Intrathecal Morphine for Cesarean Delivery: A Narrative Review.

PURPOSE OF REVIEW: Pain management is a critical aspect of care during and following a cesarean delivery. Without proper control of pain, individuals can experience poor mobility, increased thromboembolic events, and difficulty caring for the neonate in the postpartum period. There have been multiple methods for pain management for cesarean delivery and intrathecal morphine (ITM) has emerged as a prominent option for post-operative analgesia due to its efficacy, safety, and potential benefits over other treatments. This review analyzes data on efficacy, side effects, and safety of ITM and the pain control alternatives. RECENT FINDINGS: A comprehensive literature review was conducted to compare ITM with other analgesic techniques in post-cesarean patients. ITM was found to be as effective or better than other analgesic options, including bilateral quadratus lumborum block (QLB), opioid-free epidural analgesia (CSEA-EDA), and intravenous fentanyl. One study found that both ITM and oral analgesia were effective in pain control and that ITM caused fewer breakthrough pain events but had a longer duration and a greater rate of side effects than oral opioid analgesia. Commonly observed side effects of intrathecal opioids include nausea, vomiting, pruritus, and urinary retention, and it is thought that the adverse effects from intrathecal administration of opioids are short-lived. ITM may provide a decreased risk of DVT and coagulation by decreasing lower extremity weakness and numbness, thereby decreasing recovery time and increasing mobility. ITM is a safe and effective option for post-cesarean analgesia, with comparable pain relief to alternative forms of pain control, and side effects that are generally manageable. Further research is warranted to explore beneficial combinations with other methods of pain management and optimal dosing strategies.

Additive Anticonvulsive Effects of Sumatriptan and Morphine on Pentylenetetrazole-Induced Clonic Seizures in Mice.

Background and Purpose: Sumatriptan protects the brain from damage and enhance the anti-seizure effect of morphine. There is evidence that nitric oxide (NO) may mediate these effects of both drugs. In the present study, we investigated the effects of sumatriptan (0.1-20 mg/kg, intraperitoneal [i.p.]) and morphine (0.1-20 mg/kg, i.p.) alone or in combination on seizure thresholds in an in vivo model of seizure in mice. Using various NO synthase inhibitors as well as the NO precursor, we assessed possible involvement of NO signaling in these effects. Methods: Clonic seizures were induced in male Naval Medical Research Institute mice by intravenous administration of pentylenetetrazol (PTZ). Results: Acute sumatriptan administration exerted anti-convulsive effects at 0.5 (p<0.01) and 1 mg/kg (p<0.05), but pro-convulsive effects at 20 mg/kg (p<0.05). Morphine had anti-convulsive effects at 0.5 (p<0.05) and 1 mg/kg (p<0.001), but exerted pro-convulsive effect at 20 mg/kg (p<0.05). Combination treatment with sub-effective doses of sumatriptan (0.1 mg/kg) and morphine (0.1 mg/kg) significantly (p<0.05) exerted an anti-convulsive effect. Co-administration of the NO precursor L-arginine (60 mg/kg) with sub-effective doses of sumatriptan and morphine significantly (p<0.05) increased seizure threshold compared with sumatriptan alone, but not sumatriptan+morphine group. While concomitant administration of either the non-selective NO synthase (NOS) inhibitor L-NG-nitroarginine methyl ester (5 mg/kg) or the selective inducible NOS inhibitor aminoguanidine (50 mg/kg) with combined sub-effective doses of morphine and sumatriptan produced significant anticonvulsive effects, concomitant administration with the selective neuronal NOS inhibitor 7-nitroindazole (30 mg/kg) inhibited this effect. Conclusions: Our data suggest a possible role for the NO signaling in the anticonvulsive effects of combined sumatriptan and morphine on the PTZ-induced clonic seizures in mice.

Effect of repeated intraperitoneal injections of different concentrations of oxycodone on immune function in mice.

Background: The effect of oxycodone as an opioid receptor agonist on immune function is still controversial. In this study, we investigated the possible effects of oxycodone on immune function in mice and its possible mechanisms of action. Methods: By repeated intraperitoneal injections of 25 mg/kg morphine and 5 mg/kg, 20 mg/kg, and 60 mg/kg oxycodone, we assessed possible changes in the number of splenic lymphocytes and inflammatory cytokines in the serum of mice. CD4+ T cells and CD8+ T cells were sorted from the spleen to observe whether the expression levels of opioid receptors and downstream signals were altered. Results: Repeated administration of oxycodone at a dose above 20 mg/kg resulted in significant weight loss. Repeated administration of oxycodone exhibits significant dose-dependent reduction in CD4+ T cells, with little effect on CD8+ T cells and little effect on inflammatory cytokine levels. Low- and intermediate-dose oxycodone increased the mRNA expression level of MOR, KOR, and DOR to varying degrees. Moreover, oxycodone increases the mRNA expression levels of the TLR4 signaling pathway to varying degrees. Conclusion: Repeated intraperitoneal injection of oxycodone induces immunosuppression in mice.

Attenuation of acute postoperative pain and opioid requirement with the use of magnesium sulfate in patients undergoing limb amputations.

OBJECTIVE: To compare the effects of magnesium sulphate on the total dose of intravenous morphine consumption postoperatively following limb amputations along with rescue analgesia requirement, pain scores and side effects. METHODS: This prospective, triple-blinded, randomised controlled study was conducted from October 2021 to May 2022 at the Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan, and comprised of patients scheduled for limb amputations. They were randomised into 2 equal groups. The anaesthesia protocol was uniform for all patients. Intervention group A was administered 30mg/kg loading dose and 10mg/kg/hr maintenance dose of magnesium sulphate intravenously, while patients in control group B received the same amount of plain isotonic saline. Morphine consumption, including that used for rescue analgesia and patient-controlled analgesia, was measured for 24 hours postoperatively. Numeric rating scale was used for the evaluation of postoperative pain in both groups at 15min, 1h, 2h, at discharge from the post-anaesthesia care unit and at 12h and 24h in the ward. Data was analysed using SPSS 23. RESULTS: Of the 24 patients enrolled, the study was completed by 20(83.33%). There were 10(50%) patients in group A; 8(40%) males and 2(20%) females with mean age 24.8±14.14 years and mean surgery time 130.5±47.86 minutes. There were 10(50%) patients in group B; 8(40%) males and 2(20%) females with mean age 23.2±7.4 years and mean surgery time 117±23.85 minutes (p>0.05). Total morphine used over 24 hours in group A was 16±3.1 mg compared to 29.6±11.2 mg in group B (p<0.05). The time for first use of patient-controlled analgesia after arriving in the postanaesthesia care unit was significantly delayed in group A (72.2±24.95 minutes) compared to that in group B (25±26.68 minutes) (p<0.05). Pain scores were significantly higher in the group B at 15min compared to group A (p<0.05), but not at the rest of the time points (p>0.05). CONCLUSIONS: Intravenous magnesium sulphate proved to be effective in lowering postoperative opioid requirement following limb amputations.

Effects of Thymbra spicata extract and Thymol on morphine withdrawal syndrome in mice (insights to the liver function, antioxidant, and behavioral responses).

Safe chemicals for drug withdrawal can be extracted from natural sources. This study investigates the effects of clonidine and Thymbra spicata extract (TSE) on mice suffering from morphine withdrawal syndrome. Thymol, which is the active constituent in TSE, was also tested. A total of 90 mice were divided into nine groups. Group 1 was the control group, while Group 2 was given only morphine, and Group 3 received morphine and 0.2 mg/kg of clonidine. Groups 4-6 were given morphine along with 100, 200, and 300 mg/kg of TSE, respectively. Groups 7-9 received morphine plus 30, 60, and 90 mg/kg of Thymol, respectively, for 7 days. An oral naloxone challenge of 3 mg/kg was used to induce withdrawal syndrome in all groups. Improvement of liver enzyme levels (aspartate aminotransferase, alkaline phosphatase, and alanine transaminase) (p < .01) and behavioral responses (frequencies of jumping, frequencies of two-legged standing, Straub tail reaction) (p < .01) were significantly observed in the groups receiving TSE and Thymol (Groups 4-9) compared to Group 2. Additionally, antioxidant activity in these groups was improved compared to Group 2. Nitric oxide significantly decreased in Groups 4 and 6 compared to Groups 2 and 3 (p < .01). Superoxide dismutase increased dramatically in Groups 5, 8, and 9 compared to Groups 2 and 3 (p < .01). Groups 5-9 were significantly different from Group 2 in terms of malondialdehyde levels (p < .01). Certain doses of TSE and Thymol were found to alleviate the narcotics withdrawal symptoms. This similar effect to clonidine can pave the way for their administration in humans.

Ferroptosis inhibitor ferrostatin-1 attenuates morphine tolerance development in male rats by inhibiting dorsal root ganglion neuronal ferroptosis.

Background: Ferrostatin-1 and liproxstatin-1, both ferroptosis inhibitors, protect cells. Liproxstatin-1 decreases morphine tolerance. Yet, ferrostatin-1's effect on morphine tolerance remains unexplored. This study aimed to evaluate the influence of ferrostatin-1 on the advancement of morphine tolerance and understand the underlying mechanisms in male rats. Methods: This experiment involved 36 adult male Wistar albino rats with an average weight ranging from 220 to 260 g. These rats were categorized into six groups: Control, single dose ferrostatin-1, single dose morphine, single dose ferrostatin-1 + morphine, morphine tolerance (twice daily for five days), and ferrostatin-1 + morphine tolerance (twice daily for five days). The antinociceptive action was evaluated using both the hot plate and tail-flick tests. After completing the analgesic tests, tissue samples were gathered from the dorsal root ganglia (DRG) for subsequent analysis. The levels of glutathione, glutathione peroxidase 4 (GPX4), and nuclear factor erythroid 2-related factor 2 (Nrf2), along with the measurements of total oxidant status (TOS) and total antioxidant status (TAS), were assessed in the tissues of the DRG. Results: After tolerance development, the administration of ferrostatin-1 resulted in a significant decrease in morphine tolerance (P < 0.001). Additionally, ferrostatin-1 treatment led to elevated levels of glutathione, GPX4, Nrf2, and TOS (P < 0.001), while simultaneously causing a decrease in TAS levels (P < 0.001). Conclusions: The study found that ferrostatin-1 can reduce morphine tolerance by suppressing ferroptosis and reducing oxidative stress in DRG neurons, suggesting it as a potential therapy for preventing morphine tolerance.

Fragile Treg cells: traitors in immune homeostasis?

Regulatory T (Treg) cells play a key role in maintaining immune tolerance and tissue homeostasis. However, in some disease microenvironments, Treg cells exhibit fragility, which manifests as preserved FoxP3 expression accompanied by inflammation and loss of immunosuppression. Fragile Treg cells are formatively, phenotypically and functionally diverse in various diseases, further complicating the role of Treg cells in the immunotherapeutic response and offering novel targets for disease treatment by modulating specific Treg subsets. In this review, we summarize findings on fragile Treg cells to provide a framework for characterizing the formation and role of fragile Treg cells in different diseases, and we discuss how this information may guide the development of more specific Treg-targeted immunotherapies.

Evaluation of Postoperative Efficacy and Safety of Celecoxib in Children Hospitalized After Adenotonsillectomy.

OBJECTIVE: The choice of optimal analgesia following an adenotonsillectomy is a clinical issue because of the risk of respiratory depression and bleeding. The objective of this study was to assess the effect of celecoxib on opioid use and pain scores in children hospitalized after adenotonsillectomy and to document its adverse effects. METHODS: This retrospective study was conducted in a tertiary care pediatric hospital. We compared a group of subjects aged 1 to 17 years who were prescribed celecoxib and opioids between January 2017 and June 2020 following an adenotonsillectomy during a 3-day or less hospitalization to a group of matched controls for sex, age, and length of stay who were prescribed opioids. RESULTS: A total of 228 patients were identified (76 in the celecoxib + opioids group, 152 in the control group). Opioid use, in oral morphine equivalent daily dose, was lower in the celecoxib + opioids group at 0 to 24 hours of hospitalization (0.15 vs 0.20 mg/kg/day, p = 0.05). Initiating celecoxib within 24 hours of surgery (n = 60) significantly reduced opioid requirement for up to 48 hours compared with controls (0-24 hours: 0.12 vs 0.20 mg/kg/day, p = 0.002; 25-48 hours: 0.02 vs 0.09 mg/kg/day, p = 0.001). A shorter length of stay was observed for patients receiving celecoxib + opioids during the first 24-hour post--operative period (27 vs 32 hours, p = 0.01). With celecoxib use, no significant change in pain scores and occurrence of adverse effects including bleeding was found. CONCLUSIONS: Using celecoxib early after an adenotonsillectomy has reduced both opioid use and duration of hospital stay without increasing adverse effects or bleeding.

Regional anesthesia is safe for use in intramedullary nailing of low-energy tibial shaft fractures.

PURPOSE: The purpose was to compare perioperative outcomes of patients who underwent general or regional anesthesia for intramedullary (IM) nailing of tibial shaft fractures (TSFs). METHODS: Retrospective chart review was performed on a consecutive series of low-energy TSF patients who presented to a single academic medical center and a level 1 trauma center who underwent operative repair with a reamed IM nail. Collected information included demographics, injury information, anesthesia type (general or regional i.e. peripheral nerve block), intra-operative opiate consumption (converted to morphine milliequivalents [MME], and post-operative pain visual-analog scale [VAS] pain scores. Patients were divided into 3 groups based on the type of anesthesia received and univariate analysis was performed to compare the 3 groups. RESULTS: Seventy-six patients were included, with an average age of 44.47±16.0 years. There were 38 (50 %) who were administered general anesthesia and 38 (50 %) who were administered regional anesthesia in the form of a peripheral nerve block. There were no differences between the groups with respect to demographics, medical co-morbidities, rate of open fractures or AO/OTA fracture classification. Regional anesthesia patients received less intra-operative MME than general anesthesia patients (17.57±10.6, 28.96±13.8, p < 0.001). Patients who received regional anesthesia also spent less time in the operating room, received less MME on post-operative day 1, and ambulated further on post-operative day 1, however none of these differences were statistically significant. There were no cases of missed post-operative compartment syndrome or complications related to the administration of the peripheral nerve block. CONCLUSIONS: Regional anesthesia in TSF surgery received less intra-operative opioid requirements, without any untoward effects. LEVEL OF EVIDENCE: Therapeutic Level III.

Effects of Acetic Acid and Morphine in Shore Crabs, Carcinus maenas: Implications for the Possibility of Pain in Decapods.

Noxious chemicals, coupled with morphine treatment, are often used in studies on pain in vertebrates. Here we show that injection of morphine caused several behavioural changes in the crab, Carcinus maenas, including reduced pressing against the sides of the enclosure and more rubbing and picking at the mouth parts and, at least for a short time, more defensive displays. Subsequent injection of acetic acid into one rear leg caused rubbing of the injected leg and the injected leg was held vertically off the ground. These activities directed at or involving the specific leg are consistent with previous observations of directed behaviour following noxious stimuli and are consistent with the idea that decapods experience pain. Further, acetic acid but not injection of water induced autotomy of the injected leg in these animals. Because autotomy is temporally associated with directed behaviour, it is possible that the autotomy is a pain-related response. Acetic acid is clearly a noxious substance when applied to decapods. However, morphine had no effect on the activities associated with acetic acid injection and thus there is no evidence for an analgesic effect. Further, the injection of acetic acid did not interfere with behavioural effects of morphine. The activities directed towards the site of injection are like those observed with injection, or with external application, of various noxious substances and the present study adds to a growing body of knowledge about possible pain in decapods.

Meperidine compared to morphine for rigors associated with monoclonal antibody-related infusion reactions.

INTRODUCTION: Infusion reactions, characterized by symptoms such as rigors, fever, and hypotension, are common adverse events that occur during monoclonal antibody (MAB) therapy. The treatment of rigors often involves opioids, most commonly meperidine, despite limited evidence supporting use in the setting of MAB infusions. This study aims to compare the efficacy and safety of intravenous (IV) meperidine and morphine is treatment of MAB-related rigors, filling a significant gap in the literature. METHODS: This was a single-center, retrospective cohort study which reviewed patients either inpatient or within outpatient infusion centers from January 2015 to January 2024. Patients receiving IV 2 mg morphine or 25 mg meperidine for MAB-related rigors were included. The primary outcome was defined as the number of opioid doses required for rigors ablation. Secondary outcomes included rates of naloxone administration and documented sedation. RESULTS: A total of 1251 administration events were screened, of which 127 and 26 rigor events were in the meperidine and morphine cohorts, respectively, were included. A majority of both cohorts required only one dose of either agent for rigors ablation with <20% of either cohort requiring 2 or more doses (p = 0.539). Low rates of sedation were observed in both groups. CONCLUSION: Both meperidine and morphine effectively manage MAB-related rigors within minimal safety concerns. These findings suggest that morphine is a suitable alternative to meperidine for this indication, which may influence future formulary decision, provide alternatives for drug shortage, and optimize supportive care for patients undergoing MAB therapy.

S-nitrosoglutathione reductase alleviates morphine analgesic tolerance by restricting PKCα S-nitrosation.

Morphine, a typical opiate, is widely used for controlling pain but can lead to various side effects with long-term use, including addiction, analgesic tolerance, and hyperalgesia. At present, however, the mechanisms underlying the development of morphine analgesic tolerance are not fully understood. This tolerance is influenced by various opioid receptor and kinase protein modifications, such as phosphorylation and ubiquitination. Here, we established a murine morphine tolerance model to investigate whether and how S-nitrosoglutathione reductase (GSNOR) is involved in morphine tolerance. Repeated administration of morphine resulted in the down-regulation of GSNOR, which increased excessive total protein S-nitrosation in the prefrontal cortex. Knockout or chemical inhibition of GSNOR promoted the development of morphine analgesic tolerance and neuron-specific overexpression of GSNOR alleviated morphine analgesic tolerance. Mechanistically, GSNOR deficiency enhanced S-nitrosation of cellular protein kinase alpha (PKCα) at the Cys78 and Cys132 sites, leading to inhibition of PKCα kinase activity, which ultimately promoted the development of morphine analgesic tolerance. Our study highlighted the significant role of GSNOR as a key regulator of PKCα S-nitrosation and its involvement in morphine analgesic tolerance, thus providing a potential therapeutic target for morphine tolerance.

Nalbuphine versus morphine: an adjuvant to spinal anesthesia for controlling pain after total knee arthroplasty: a propensity score-matched analysis.

BACKGROUND: Nalbuphine, a synthetic k-agonist and µ-antagonist, provides efficient pain relief while reducing opioid-related adverse effects. This study aims to compare the efficacy of intrathecal nalbuphine (ITN) with intrathecal morphine (ITM) for post-TKA pain. METHODS: A retrospective cohort analysis of 131 patients who underwent TKA with spinal anesthesia (SA), a single shot of adductor canal block, and periarticular injections was conducted. The patients were divided into 2 groups, Group N received 0.8 mg nalbuphine, and Group M received 0.2 mg morphine as an adjuvant to SA. Propensity-score matching was employed to compare the visual analog scales (VAS) of postoperative pain intensity, cumulative morphine use (CMU), maximum knee flexion angle, straight leg raise (SLR) ability, incidence of postoperative nausea and vomiting (PONV), and length of hospital stay (LHS). RESULTS: The mean VAS of group M were significantly lower than group N at 6, 12, 18, and 24 h (P < 0.01). Group M had lower CMU than group N at 24 h (P < 0.01) and 48 h (P < 0.01), while there was no significant difference between groups in terms of knee flexion angle and SLR at any time point. Additionally, 29.3 and 57.9% of patients in group N and M experienced PONV, respectively (p = 0.04), and group N had significantly shorter LHS compared to group M (P < 0.001). CONCLUSION: Although, intrathecal morphine (ITM) still provides better pain control particularly in the first 24 h, patients who received intrathecal nalbuphine (ITN) had significantly fewer incidence of PONV, and shorter LHS.

Peripheral nerve blocks for analgesia following cesarean delivery A narrative review.

Spinal and epidural blocks are commonly employed for pain relief during and following cesarean section. Intrathecal morphine (ITM) has been the gold standard for the same for many years. In recent times, many peripheral nerve blocks (PNBs) have been tried for postoperative analgesia following cesarean delivery (PACD). This article has reviewed the common PNBs used for PACD. The role of PNBs along with ITM has been studied and the current best strategy for PACD has also been explored. Currently, Ilio-inguinal nerve and anterior transversus abdominis plane block in conjunction with intrathecal morphine have been found to be the most effective strategy, providing lower rest pain at 6 hours as compared to ITM alone. In patients not receiving intrathecal morphine, recommended PNBs are lateral transversus abdominis plane block, single shot local anesthetic wound infiltration, or continuous wound infiltration with catheter below rectus fascia. PNBs are recommended for PACD. They have an opioid-sparing effect and are devoid of adverse effects associated with central neuraxial blocks such as hypotension, bradycardia, and urine retention. However, caution must be observed with PNBs for possible local anesthetic toxicity due to the large volumes of drug required.

Effect of Morphine Used to Relieve Dyspnea Due to Heart Failure on Delirium.

Background: Delirium management is crucial in palliative care. Morphine effectively relieves dyspnea due to heart failure. However, the effect of morphine, which is used to relieve dyspnea due to heart failure, on the incidence of delirium has not been examined to date. Objective: To evaluate the effect of morphine, which is used to relieve dyspnea due to heart failure, on delirium. Design: Retrospective observational study. Setting/Subjects: Subjects were identified from Osaka University Hospital records, located in Japan, from January 1, 2010, to September 30, 2021. The case group consisted of admissions for heart failure or cardiomyopathy registered in electronic medical records. Morphine was administered to relieve dyspnea due to heart failure, and no surgeries or procedures were performed. The control group consisted of admissions for heart failure or cardiomyopathy in the Diagnosis Procedure Combination (DPC) database, which did not include administration of morphine, oxycodone, or fentanyl during the hospitalization period and patients did not undergo surgery or any other procedure. Measurements: The incidence of delirium was assessed. Results: The odds ratios for morphine in the multivariate logistic regression analysis with propensity score and univariate logistic regression analysis after propensity score matching were 1.406 (95% confidence interval (CI) [0.249-7.957]) and 1.034 (95% CI [0.902-1.185]), respectively. Conclusions: Morphine, which is used to relieve dyspnea due to heart failure, had minimal effect on the incidence of delirium. This information is likely to be beneficial for the future use of morphine in the management of dyspnea in patients with heart failure.

A systematic review of morphine equivalent conversions in plastic surgery: Current methods and future directions.

INTRODUCTION: Protocols surrounding opioid reduction have become commonplace in plastic surgery to improve peri-operative outcomes. Within such protocols, opioid requirement is a frequently analyzed outcome. Though often examined, there is no literature standard conversion for morphine milligram equivalents (MME) at present, leading to questionable external validity. We hypothesized significant heterogeneity in MME reporting would exist within plastic surgery literature. METHODS: Following the PRISMA guidelines, the authors conducted a systematic review of 16 journals. Clinical studies focused on opioid reduction within plastic surgery were identified. Primary outcomes included reporting of morphine equivalents (ME) delivery (IV/oral), operative ME, inpatient ME, outpatient ME, timeline, and method of calculation. RESULTS: Among the 101 studies analyzed, 73% reported opioid requirements in the form of ME. Among those that used ME, 3% reported IV ME, 41% reported oral, 32% reported both, and 25% gave no indication of either. Operative ME were reported in 19% of studies. Furthermore, 54% of studies reported inpatient ME whereas 32% of studies reported outpatient ME. Only 19% reported the number of days opioids were consumed postoperatively. Moreover, 27% of the studies reported the actual method of ME conversion, with 17 unique methods described. Only 8 studies (8%) reported using the Center for Disease Control and Prevention guidelines for ME conversion. CONCLUSION: There is significant variability among the reported ME conversion methodology within plastic surgery literature. Highlighting these discrepancies is an essential step in creating and implementing a single, standard method to mitigate opioid morbidity in plastic surgery and to optimize enhanced recovery protocols.