Comparison of analgesic efficacy of oxycodone and morphine in postoperative intravenous patient-controlled analgesia

Determining the Maximum Tolerable Concentration of Ropivacaine to Maintain Sensation of the Nerve Root in Percutaneous Endoscopic Transforaminal Lumbar Discectomy: Can Epidural Anaesthesia Achieve Pain-Tactile Separation Block to Avoid Nerve Injury?

Introduction

Nerve injury is a serious complication of percutaneous endoscopic transforaminal lumbar discectomy due to nerve root contact. The maximum tolerable concentration (MTC) of ropivacaine concentration for epidural anaesthesia, is defined as the concentration that minimises pain while preserving the sensation of the nerve roots. This distinct advantage allows the patient to provide feedback to the surgeon when the nerve roots are contacted.

Methods

We used a biased-coin design to determine the MTC, which was estimated by the 10% effective concentration (EC10), ie, the concentration at which 10% of patients lost sensation in the nerve roots. The determinant for positive response was lack of sensory feedback upon contact with the nerve root, and the feedback from occurrence of sensations in the innervation area upon contact with the nerve root was defined as a negative response. Primary outcome was the response from contact nerve root. Secondary outcomes were the type and number of statements of negative response and each patient's pain score during surgery.

Results

Fifty-four patients were included in this study. The EC10 was 0.434% (95% CI: 0.410%, 0.440%) using isotonic regression in comparison with 0.431% (95% CI: 0.399%, 0.444%) using probit regression. Three type statements of negative response were reported including "tactile sensation", radiculalgia, and numbness.

Conclusion

The MTC of ropivacaine used for epidural anaesthesia was 0.434% to avoid nerve injury in percutaneous endoscopic transforaminal lumbar discectomy.

Oxycodone: A Current Perspective on Its Pharmacology, Abuse, and Pharmacotherapeutic Developments

Oxycodone, a semisynthetic derivative of naturally occurring thebaine, an opioid alkaloid, has been available for more than 100 years. Although thebaine cannot be used therapeutically due to the occurrence of convulsions at higher doses, it has been converted to a number of other widely used compounds that include naloxone, naltrexone, buprenorphine, and oxycodone. Despite the early identification of oxycodone, it was not until the 1990s that clinical studies began to explore its analgesic efficacy. These studies were followed by the pursuit of several preclinical studies to examine the analgesic effects and abuse liability of oxycodone in laboratory animals and the subjective effects in human volunteers. For a number of years oxycodone was at the forefront of the opioid crisis, playing a significant role in contributing to opioid misuse and abuse, with suggestions that it led to transitioning to other opioids. Several concerns were expressed as early as the 1940s that oxycodone had significant abuse potential similar to heroin and morphine. Both animal and human abuse liability studies have confirmed, and in some cases amplified, these early warnings. Despite sharing a similar structure with morphine and pharmacological actions also mediated by the μ-opioid receptor, there are several differences in the pharmacology and neurobiology of oxycodone. The data that have emerged from the many efforts to analyze the pharmacological and molecular mechanism of oxycodone have generated considerable insight into its many actions, reviewed here, which, in turn, have provided new information on opioid receptor pharmacology. SIGNIFICANCE STATEMENT: Oxycodone, a μ-opioid receptor agonist, was synthesized in 1916 and introduced into clinical use in Germany in 1917. It has been studied extensively as a therapeutic analgesic for acute and chronic neuropathic pain as an alternative to morphine. Oxycodone emerged as a drug with widespread abuse. This article brings together an integrated, detailed review of the pharmacology of oxycodone, preclinical and clinical studies of pain and abuse, and recent advances to identify potential opioid analgesics without abuse liability.

Intraoperative Diastolic Hypotension-Prolonged Postoperative Hospital Stay in Patients with Gastric Cancer: A Retrospective Cohort Study with Propensity Score Matching

Purpose

In patients undergoing surgical resection for gastric cancer, perioperative hemodynamic fluctuations may affect organ perfusion, increase the incidence of postoperative complications, and prolong hospital stay.

Patients and Methods

We retrospectively identified patients who underwent resection for gastric cancer at our institution from April 1, 2015 to October 30, 2018. Demographic information, perioperative data, and information on postoperative recovery were recorded. The primary outcome was length of postoperative hospital stay; the secondary outcome was incidence of postoperative complications. Propensity score matching was performed. The associations between perioperative factors and postoperative hospital stay were analyzed using multivariable logistic regression models in the full and matched cohorts.

Results

In total, 933 patients were included; of these, 676 had diastolic hypotension (defined as diastolic blood pressure <60 mmHg for >10 min). In both cohorts, patients with diastolic hypotension had statistically significantly longer postoperative hospital stay (full: mean 14.5 ± standard deviation 10.2 vs 11.6 ± 6.5 days, P < 0.001; matched: 13.7 ± 9.9 vs 11.7 ± 6.6 days, P = 0.009) and a higher incidence of postoperative complications (full: 170 [25.1%] vs 27 [10.5%] cases, P < 0.001; matched: 60 [24.4%] vs 33 [13.4%] cases, P = 0.003), compared with patients without diastolic hypotension. After correction for confounding factors, intraoperative diastolic hypotension was associated with longer postoperative hospital stay in both the full and the matched cohort (full: HR, 1.535 [95% CI, 1.115-2.114], P = 0.009; matched: HR, 1.532 [95% CI, 1.032-2.273], P = 0.034).

Conclusion

For patients with gastric cancer, intraoperative diastolic hypotension may increase the incidence of postoperative complications and prolong postoperative hospital stay.

Effects of Ultramicronized N-Palmitoylethanolamine Supplementation on Tramadol and Oxycodone Analgesia and Tolerance Prevention

Chronic pain management requires increasing doses of opioids, the milestone of painkillers, which may result in the onset of tolerance with exacerbated side effects. Maintaining stable analgesia with low doses of opioids is thus imperative. N-palmitoylethanolamine (PEA) is an endogenous lipid compound endowed with pain-relieving as well as anti-inflammatory properties. The ultramicronized formulation of PEA was recently demonstrated to be able to modulate morphine’s effects, delaying tolerance and improving efficacy. To evaluate the possible application to other opioids, in this study, we analysed the capacity of ultramicronized PEA to regulate analgesia and tolerance induced by oxycodone and tramadol. Pre-emptive and continuative treatment with ultramicronized PEA (30 mg kg⁻¹, daily, per os) delayed the onset of opioid tolerance and enhanced opioid analgesia when it was acutely administered in association with tramadol (20 mg kg⁻¹, daily, subcutaneously) or oxycodone (0.5 mg kg⁻¹, daily, subcutaneously). Moreover, PEA exerted antinociceptive effects on tolerant rats, suggesting the use of PEA together with opioids for stable, long-lasting analgesia. To that purpose, the oxycodone dose needed to be increased from 0.3 mg kg⁻¹ (day 1) up to 1 mg kg⁻¹ (day 31) in the oxycodone + vehicle group; the tramadol dose was progressively enhanced from 15 mg kg⁻¹ to 50 mg kg⁻¹ in 31 days in the tramadol + vehicle group. Acute oral co-treatment with PEA (120 mg kg⁻¹) achieved the same analgesia without increasing the dose of both opioids. The behavioural effects of PEA on opioid chronic treatment paralleled a decrease in astrocyte activation in the dorsal horn of the spinal cord (a marker of the development of opioid tolerance) and with a modulation of mRNA expression of IL-6 and serpin-A3. In conclusion, pre- and co-administration of ultramicronized PEA delayed the development of tramadol tolerance, potentiating either oxycodone or tramadol analgesia and allowing a long-lasting analgesic effect with a low opioid dose regimen. The use of PEA is suggested for clinical purposes to support the opioid-based management of persistent pain.

Oxycodone target concentration dosing for acute pain in children

BACKGROUND

Oxycodone pharmacokinetics have been described in premature neonates through to obese adults. Covariate influences have been accounted for using allometry (size) and maturation of oxycodone clearance with age. The target concentration is dependent on pain intensity that may differ over pain duration or between individuals.

METHODS

We assumed a target concentration of 35 mcg.L^-1 (acceptable range ±20%) to be associated with adequate analgesia without increased risk of adverse effects from respiratory depression. Pharmacokinetic simulation was used to estimate dose in neonates through to obese adults given intravenous or parenteral oxycodone.

RESULTS

There were 84% of simulated oxycodone concentrations within the acceptable range during maintenance dosing. Variability around the simulated target concentration decreased with age. The maturation of oxycodone clearance is reflected in changes to context-sensitive halftime where clearance is immature in neonates compared with older children and adults. The intravenous loading and maintenance doses for a typical 5-year-old child are 100 mcg.kg^-1 and 33 mcg.kg^-1 .h^-1 . In a typical adult, the loading dose is 100 mcg.kg^-1 and maintenance dose 23 mcg.kg^-1 .h^-1 .

CONCLUSION

Simulation was used to suggest loading and maintenance doses to attain an oxycodone concentration of 35 mcg.L^-1 predicted in adults. Although the covariates age and weight contribute 92% variability for clearance, there remains variability accounting for 16% of concentrations outside the target range. Duration of analgesic effect after ceasing infusion is anticipated to be longer in neonates where context-sensitive halftime is greater than older children and adults.

Perioperative Use of Glucocorticoids and Intraoperative Hypotension May Affect the Incidence of Postoperative Infection in Patients with Gastric Cancer: A Retrospective Cohort Study

Background

In patients undergoing surgical resection for gastric cancer, postoperative complications—in particular, postoperative infections—remain an important problem and can result in delayed recovery and increased postoperative mortality.

Objective

To investigate the association between perioperative anesthesia management and postoperative infectious complications in patients undergoing resection for gastric cancer.

Design

Retrospective cohort study.

Setting

A single-center study performed from April 1, 2015, to June 30, 2018, at Peking University Cancer Hospital.

Patients

Patients who underwent resection for gastric cancer.

Main Outcome Measures

Demographic information, perioperative data (including anesthesia-related data, surgery-related data, and cancer diagnosis), and information on postoperative recovery were recorded. The primary outcome was incidence of postoperative infection; the secondary outcome was length of hospital stay. The associations between perioperative factors and postoperative infectious complications were analyzed using multivariable logistic regression models and the classification tree method.

Results

A total of 880 patients were included in the study; of these, 111 (12.6%) had postoperative infectious complications during hospitalization, including 78 surgical site infections and 62 remote infections. After correction for confounding factors on logistic multivariable analysis, perioperative use of glucocorticoids was associated with a lower incidence of postoperative infection (hazard ratio 0.968, 95% confidence interval 0.939 to 0.997, P=0.029), and intraoperative systolic blood pressure <90 mmHg for >10 min was associated with a higher incidence of postoperative infection (hazard ratio 2.112, 95% confidence interval 1.174 to 3.801, P=0.013). In addition, older age, preoperative hypoproteinemia, and total gastrectomy were identified as independent predictors of postoperative infection.

Conclusion

For patients with gastric cancer, perioperative use of glucocorticoids and avoiding intraoperative hypotension may decrease the incidence of postoperative infectious complications.

Oxycodone versus morphine for analgesia after laparoscopic endometriosis resection

Background

The objective of this study was to compare the analgesic potency of oxycodone versus morphine after laparoscopic deep infiltrating endometriosis resection.

Methods

Fifty patients undergoing laparoscopic deep infiltrating endometriosis resection were randomized to receive oxycodone or morphine intravenous-PCA after surgery. The primary outcome was opioid consumption during the 24 h after surgery. Secondary outcomes included time to first request for analgesia, the number of bolus, pain, sedation, nausea, vomiting, respiratory depression, and bradycardia. The prominent pain that caused patients to press the analgesic device was also recorded.

Results

Oxycodone consumption (14.42 ± 2.83) was less than morphine consumption (20.14 ± 3.83). Compared with the morphine group, the total number of bolus (78 vs 123) was less and the average time to first request for analgesia (97.27 ± 59.79 vs 142.17 ± 51) was longer in the oxycodone group. The incidence of nausea was higher in the morphine group than in the oxycodone group at 0–2 h (45.45% vs 17.19%), 2–4 h (50% vs 17.19%),12–24 h (40.91% vs 13.04%) and 0–24 h (39.17% vs 19.13%). The overall incidence of vomiting was higher in the morphine group (27.27% vs 13.92%). There was no difference in visual analogue scale score, the incidence of respiratory depression, and bradycardia between groups. Of the three types of pain that prompted patients to request analgesia, the incidence of visceral pain was highest (59.9%, P < 0.01).

Conclusion

Oxycodone was more potent than morphine for analgesia after laparoscopic endometriosis resection, and oxycodone has fewer side effects than morphine.

Name of the registry: Chinese Clinical Trial Registry

Trial registration number: ChiCTR1900021870

URL of trial registry record:http://www.chictr.org.cn/edit.aspx?pid=35799&htm=4

Date of registration: 2019/3/13 0:00:00

Intrathecal morphine versus transversus abdominis plane block for caesarean delivery: a systematic review and meta-analysis

BACKGROUND

The number of caesarean deliveries has been increasing. Although intrathecal morphine (ITM) can relieve pain and is widely applied in caesarean deliveries, it is associated with many side effects. Transversus abdominis plane block (TAPB), a new analgesic technology, has also began playing a certain role after caesarean delivery, with fewer adverse effects. This study mainly compares the analgesic and adverse effects of ITM and TAPB in caesarean delivery.

METHODS

We systematically searched PubMed, Cochrane Library, EMBASE, and Web of Science, for randomised controlled trials (RCTs) published before 9 October, 2020 to compare the effects of ITM and TAPB. Primary outcome of the study was the pain score at rest 24 h after caesarean delivery, whereas the secondary outcomes were the pain score at movement 24 h after operation, postoperative nausea and vomiting (PONV), itching, and morphine consumption. For the outcome assessment, we conducted a sensitivity analysis.

RESULT

Six RCTs involving 563 patients and meeting the study inclusion criteria were included in this study. Results indicated no significant difference in the pain score between ITM and TAPB at 24 h of rest or movement. The sensitivity analysis results indicated that the resting pain score (95% CI = - 1.27 to - 0.28; P = 0.002) and 24-h moving pain score (95% CI = - 1.8 to - 0.07; P = 0.03) of the ITM group were lower than those of the TAPB group. The consumption of morphine in the ITM group was lower than in the TAPB group (95% CI = 1.92 to 4.87; P < 0.00001); however, in terms of adverse reactions, the incidence of pruritus (95% CI = 1.17 to 8.26; P = 0.02) and PONV (95% CI = 1.92 to 4.87, P < 0.00001) in the ITM group was higher than in the TAPB group.

CONCLUSION

Parturients in the ITM and TAPB groups exhibited similar analgesic effects. However, in the sensitivity analysis performed by eliminating the studies causing heterogeneity, the ITM group was found to have superior analgesic effects compared with the TAPB group, with less morphine consumption. Differently, the TAPB group displayed less side effects such as PONV. Therefore, TAPB is still a valuable analgesia option for patients who cannot use ITM for analgesia after caesarean delivery or those having a high risk of PONV.

TRIAL REGISTRATION

Registration number: Registered on Prospero with the registration number of CRD42020210135 .

Effect of intravenous oxycodone on the physiologic responses to extubation following general anesthesia

BACKGROUND

Endotracheal intubation and extubation may cause undesirable hemodynamic changes. Intravenous oxycodone has recently been introduced and used for relieving hemodynamic alterations in response to intubation, but there is insufficient information regarding its application in stabilizing hemodynamics during extubation in the patients emerging from general anesthesia.

METHODS

One hundred patients, who had undergone assorted laparoscopic surgeries under general anesthesia, were randomly assigned to Control group (saline injection, 50 cases) and Study group (intravenous injection of 0.08 mg/kg oxycodone immediately after completion of the surgical procedure, 50 cases). Blood pressure, heart rate, blood oxygen saturation (SpO₂) as well as blood concentrations of epinephrine, norepinephrine, and cortisol were recorded or measured immediately before extubation (T₀), during extubation (T₁), as well as one minute (T₂), 5 min (T₃), and 10 min after extubation (T₄). In addition, coughing and restlessness, time of eye-opening, and duration from completing surgery to extubation as well as Ramsay Sedation Scale were analyzed.

RESULTS

Blood pressure and heart rate as well as blood concentrations of epinephrine, norepinephrine, and cortisol were significantly higher in the Control group compared with the Study group at the time of extubation as well as 1, 5, and 10 min after extubation (P < 0.05). When the patients emerged from general anesthesia, 70 % of the Control group had cough, which was significantly higher than that of Study group (40 %, P < 0.05). Significantly higher number of patients manifested restlessness in the Control group before (40 %) and after extubation (20 %) compared with that in the Study group (20 and 2 %, respectively, P < 0.05). In addition, patients of Control group had lower Ramsay score at extubation (1.7 ± 0.7) as well as 30 min after extubation (2.4 ± 0.9) compared to that of the patients of Study group (2.2 ± 0.9, and 3.0 ± 0.8, respectively, P = 0.003 and 0.001).

CONCLUSIONS

Intravenous oxycodone attenuated alterations of hemodynamics and blood hormones associated with extubation during emergence from general anesthesia.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR2000040370 (registration date: 11-28-2020) "'retrospectively registered".

Feasibility of using oxycodone as the sole opioid for induction and maintenance of general anaesthesia in minor/moderate surgery: a prospective, observational, descriptive study

Objectives

This study presented the feasibility of oxycodone as the sole opioid for general anaesthesia in minor/moderate surgery.

Methods

In this prospective, observational, descriptive study, 62 patients were enrolled and received intravenous oxycodone as the sole opioid for the induction and maintenance of general anaesthesia. We observed all of these patients to determine whether oxycodone alone could provide sufficient intraoperative and postoperative analgesia, as well as to record the extubation times and adverse events.

Results

A total oxycodone dose of 0.316 ± 0.05 mg/kg was used for induction and maintenance of general anaesthesia. The dose could maintain haemodynamic stability during surgery and good postoperative analgesia. Oxycodone caused deep sedation (nine patients had Ramsey sedation scores ≥4), leading to respiratory depression and long stays in the post-anaesthesia care unit (PACU). The extubation time (16.9 ± 6.4 minutes) increased with increasing oxycodone doses.

Conclusion

Oxycodone can be used as the sole opioid for general anaesthesia in minor/moderate surgery. However, care should be taken because of its deep sedation effect.

Trial registration: This study is registered at the Chinese Clinical Trial Registry (www.chictr.org.cn): ChiCTR-opc-16009175

Pharmacogenomics of oxycodone: a narrative literature review

Oxycodone is a semisynthetic μ- and κ-opioid receptor with agonist with a broad scope of use including postoperative analgesia as well as control of neuropathic and cancer pain. Advantages over other opioids include prolonged duration of action, greater potency than morphine and lack of histamine release or ceiling effect. Individual responses to oxycodone can vary due to genetic differences. This review article aims to summarize the oxycodone literature and provide context on its pharmacogenomics and pharmacokinetics. The evidence for clinical effect of genetic polymorphisms on oxycodone is conflicting. There is stronger evidence linking polymorphic genetic enzymes CYP2D6 and CYP3A with therapeutic outcomes. Further, research is needed to discern all of oxycodone's metabolites and their contribution to the overall analgesic effect.

Ultrasound-guided transmuscular quadratus lumborum block reduced postoperative opioids consumptions in patients after laparoscopic hepatectomy: a three-arm randomized controlled trial

Background

To investigate whether transmuscular quadratus lumborum block (TQLB) combined with oxycodone-based patient-controlled intravenous analgesia (PCIA) compared with sufentanil-based patient-controlled intravenous analgesia could reduce postoperative pain and opioid consumption in patients undergoing laparoscopic hepatectomy.

Methods

Eighty patients undergoing laparoscopic hepatectomy surgery were randomly divided into Group S (Sufentanil for PCIA group), Group O (Oxycodone for PCIA group) and Group QO (transmuscular quadratus lumborum block + oxycodone for PCIA group). Primary outcome was Numerical Rating Scale (NRS) pain score when coughing at 6th hour after the operation. We summarized opioid consumption and recorded complications, opioid drug adverse reaction and analgesia satisfaction.

Results

NRS pain scores were significantly lower in Group QO while patients coughing at 6th hour after the operation compared with Group S and Group O (median (interquartile range [IQR]):Group S vs. Group O vs. Group QO 4.0 [3.0, 5.0] vs. 4.0[3.0,5.0]vs.3.0 [2.0, 3.0], p < 0.05). Within 24 h after surgery, the bolus times of PCIA (patient controlled intravenous analgesia) in the QO group was reduced which was compared with the Group S and Group O (median (interquartile range [IQR]):Group S vs. Group O vs. Group QO 13.0 [10.3, 19.5] vs. 11.5 [7.8, 18.3]vs.6.5[3.5,12.0], p < 0.05). The proportion of patients in the three groups who required additional analgesia was ranked as Group QO < Group O < Group S(p < 0.05). The analgesic satisfaction of patients in Group QO was higher than the Group S (p = 0.001) and Group O (p = 0.012).

Conclusions

TQLB combined with oxycodone-based PCIA provided satisfactory postoperative analgesia and reduced oxycodone consumption in patients following laparoscopic hepatectomy.

Trial registration

ChiCTR1900028467 (22/12/2019).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01255-3.

Perioperative Glucocorticoids are Associated with Improved Recurrence-Free Survival After Pancreatic Cancer Surgery: A Retrospective Cohort Study with Propensity Score-Matching

Purpose

Perioperative anesthetic management may affect long-term outcome after cancer surgery. This study investigated the effect of perioperative glucocorticoids on long-term survival in patients after radical resection for pancreatic cancer.

Methods

In this retrospective cohort study with propensity score-matching, patients who underwent radical resection for pancreatic cancer from January 2005 to December 2016 were recruited. Baseline and perioperative data including use of glucocorticoids for prevention of postoperative nausea and vomiting were collected. Patients were followed up by qualified personnel for cancer recurrence and survival. The primary outcome was the recurrence-free survival. Outcomes were compared before and after propensity matching. The association between perioperative glucocorticoid use and recurrence-free survival was analyzed with multivariable regression models.

Results

A total of 215 patients were included in the study; of these, 112 received perioperative glucocorticoids and 103 did not. Patients were followed up for a median of 74.0 months (95% confidence interval [CI] 68.3–79.7). After propensity score-matching, 64 patients remained in each group. The recurrence-free survivals were significantly longer in patients with glucocorticoids than in those without (full cohort: median 12.0 months [95% CI 6.0–28.0] vs 6.9 months [4.2–17.0], P<0.001; matched cohort: median 12.0 months [95% CI 5.8–26.3] vs 8.3 months [4.3–18.2], P=0.015). After correction for confounding factors, perioperative glucocorticoids were significantly associated with prolonged recurrence-free survivals (full cohort: HR 0.66, 95% CI 0.48–0.92, P=0.015; matched cohort: HR 0.54, 95% CI 0.35–0.84, P=0.007).

Conclusion

Perioperative use of low-dose glucocorticoids is associated with improved recurrence-free survival in patients following radical surgery for pancreatic cancer.

Post-operative opioid-related adverse events with intravenous oxycodone compared to morphine: A randomized controlled trial

BACKGROUND

The value of intravenous oxycodone compared to morphine remains controversial. The purpose of this trial was to compare opioid-related adverse events (ORAES) of intravenous oxycodone and morphine after total hip arthroplasty.

METHODS

Patients scheduled for total hip arthroplasty were enrolled in this study of post-operative pain treatment with intravenous oxycodone or intravenous morphine (ratio 1:1). After surgery, patients received similar drug regimens for titration in the post-operative care unit followed by intravenous patient-controlled analgesia (PCA). The primary outcome was the number of patients with ≥1 ORAEs within the first 24 hours defined as either nausea, vomiting, respiratory depression, pruritus, urinary retention requiring evacuation, allergy, hallucinations. Secondary outcomes included pain scores and opioid consumption.

RESULTS

The analysis included 238 patients with similar characteristics. There were 55 patients with at least one ORAEs in the oxycodone group vs 46 in the morphine group: 48% vs 40%, P = .19; relative risk = 1.22 (0.91:1.63). Intravenous oxycodone vs intravenous morphine requirements were respectively (median, IQR): 6 (0-11) vs 8 (0-12) mg (P = .06) for titration, 15 (8-26) vs 8 (5-16) mg (P = .001) for PCA, and 22 (12-37) mg vs 19 (11-28) mg for cumulated intravenous consumption (P = .048). During the first 24 hours, there was no difference in secondary outcomes (oxycodone vs morphine, respectively, in %): nausea (15 vs 13), vomiting (5 vs 5), urinary retention (20 vs 12) or pain scores.

CONCLUSION

This study demonstrates that IV oxycodone did not significantly reduce ORAEs within the first 24 hours compared to similar ratio of IV morphine.

Comparison of Analgesic and Adverse Effects of Oxycodone- and Fentanyl-Based Patient-Controlled Analgesia in Patients Undergoing Robot-Assisted Laparoscopic Gastrectomy Using a 55:1 Potency Ratio of Oxycodone to Fentanyl: A Retrospective Study

Purpose

Oxycodone has affinities for both kappa- and mu-opioid receptors. Therefore, it has been used for postoperative analgesia of surgeries in which visceral pain is expected to be the main cause of pain. However, there are few studies of the 55:1 potency ratio of oxycodone to fentanyl when using it as intravenous patient-controlled analgesia (IV-PCA). Thus, we compared the analgesic and adverse effects of IV-PCA using the 55:1 potency ratio of oxycodone to fentanyl in patients who underwent robot-assisted laparoscopic gastrectomy.

Patients and Methods

This retrospective study included 100 patients using an automatic PCA pump with oxycodone or fentanyl who underwent robot-assisted laparoscopic gastrectomy between January and November 2017. All patients were provided with an IV-PCA consisting of 20 μg/kg of fentanyl or 1.1 mg/kg of oxycodone mixed with 0.9% normal saline solution to a total volume of 250 mL, which was infused basally at a rate of 0.1 mL/h with a bolus dose of 1 mL and lockout time of 6 min. The primary and secondary endpoints were to evaluate the efficacies of IV-PCA using the 55:1 potency ratio of oxycodone to fentanyl on analgesic and adverse effects.

Results

Pain intensity on arrival at the post-anesthesia care unit (PACU; 3.6±1.4 vs 4.4±2.0, P=0.031) and additional analgesic requirement within an hour after surgery (including the PACU period) (12% vs 37%; P=0.005) were significantly lower in the oxycodone group (n=49) than in the fentanyl group (n=51). Regarding adverse effects, the rate of postoperative nausea within 1 h after surgery (2% vs 16%; P=0.031) was also significantly lower in the oxycodone group than that in the fentanyl group.

Conclusion

Oxycodone-based IV-PCA by dose calculations with a 55:1 potency ratio may achieve better analgesia without any significant adverse effects, when using IV-PCA in patients undergoing robot-assisted laparoscopic gastrectomy.

Comparison between total intravenous anesthesia and balanced anesthesia on postoperative opioid consumption in patients who underwent laparoscopic-assisted distal gastrectomy

Remifentanil is the most frequently prescribed opioid for total intravenous anesthesia (TIVA) or balanced anesthesia (BA), due to its favorable pharmacological properties. However, several studies have reported opioid-induced hyperalgesia and/or acute tolerance after intraoperatively using remifentanil. In addition, it is imperative to control postoperative pain with lower doses of opioid anesthetic agents. Therefore, we compared the amount of opioid consumption between TIVA with propofol-remifentanil and BA with desflurane-remifentanil, to control postoperative pain in patients who underwent laparoscopic-assisted distal gastrectomy (LADG) with gastroduodenostomy.We retrospectively evaluated demographic variables (age, gender, height, weight, and smoking habits), the duration of general anesthesia (GA), and intraoperatively administered remifentanil consumption through the electronic medical records of patients who underwent LADG with gastroduodenostomy due to early stomach cancer. The primary outcome was postoperative opioid consumption during postoperative day (POD) 2. The secondary outcomes were the incidence of any rescue opioid analgesics administered, numeric rating scale, and various adverse effects during POD 2. We categorized the data in 2 patient groups to compare TIVA with propofol-remifentanil (TIVA group) to BA with desflurane-remifentanil (BA group) on the postoperative opioid analgesic consumption.We divided 114 patients into the TIVA (46 patients) and BA (68 patients) groups. Opioid consumption as a primary outcome was significantly higher in the BA group than in the TIVA group during POD 2 except in the post-anesthesia care unit. The cumulative opioid consumption was significantly higher in the BA than in the TIVA group. The incidence of rescue analgesic at POD 2 was higher in the BA than in the TIVA group. In the TIVA group, remifentanil consumption was higher, and the duration of GA was shorter than that in the BA group. No statistically significant differences were observed when comparing other variables.Our results indicated that the maintenance of GA with TIVA (propofol-remifentanil) reduces opioid consumption for postoperative pain control compared to BA (desflurane-remifentanil) in patients undergoing LADG with gastroduodenostomy.

Sedation and Analgesia for Liver Cancer Percutaneous Radiofrequency Ablation: Fentanyl and Oxycodone Comparison

Background: Sedation and analgesia use in percutaneous radiofrequency ablation (RFPA) for liver cancer is a necessary part of the procedure; however, the optimal medicine for sedation and analgesia for PRFA remains controversial. The aim of this study was to compare the perioperative pain management, haemodynamic stability and side effects between oxycodone (OXY) and fentanyl (FEN) use in patients under dexmedetomidine sedation. Methods: Two hundred and five adults with an American Society of Anaesthesiologists physical status score of I to II were included in this study. Patients were assigned to the OXY (n=101) or FEN (n=104) group. Radiofrequency ablation was performed under spontaneous breathing and with painless anaesthesia administered intravenously. The outcomes included fluctuations in mean arterial pressure, heart rate, side effects and the perioperative numerical rating scale (NRS). Results: Radiofrequency ablation was successfully performed in 205 patients. No significant differences were observed in mean blood pressure fluctuations between the two groups despite the longer durations of ablation and total sedation time in the OXY group. The highest NRS score during the surgery and 1 hour and 2 hours after the surgery were significantly lower in the OXY group than in the FEN group. Heart rate fluctuations were significantly lower in the OXY group than in FEN group throughout the surgery. More patients in the FEN group displayed unwanted body movement and respiratory depression. Conclusions: Both oxycodone and fentanyl can be applied for liver cancer percutaneous radiofrequency ablation; however, oxycodone provides a better patient experience, lower postoperative pain, less respiratory depression and stable haemodynamic fluctuations.

An Open-Label Study of Sufentanil Sublingual Tablet 30 Mcg in Patients with Postoperative Pain

Objective

To evaluate sufentanil sublingual tablet 30 mcg (SST 30 mcg) for postoperative pain in an older patient population with comorbidities.

Design

Multicenter, open-label, single-arm study.

Setting

Nine hospitals across the United States.

Subjects

Adults aged ≥40 years who had undergone a surgical procedure.

Methods

Patients with a postoperative pain intensity score ≥4 on an 11-point numeric rating scale (NRS) were allowed to enter the study and receive SST 30 mcg as requested for pain (minimum 60-minute redosing interval) over the 12-hour study period. Efficacy was assessed by patient reports of pain intensity on the NRS and a five-point pain relief scale. Safety was monitored throughout the study; plasma sufentanil concentrations were also measured. The primary efficacy endpoint was the time-weighted summed pain intensity difference (SPID) to baseline over 12 hours (SPID12).

Results

Of the 140 patients enrolled, 69% were American Society of Anesthesiologists Physical Class II or III, 44% had a body mass index (BMI) ≥30 mg/kg², and 29% had hepatic and/or renal impairment. Average age was 54.7 years (SD = 9.9 years), and average baseline pain intensity was 6.2 (SD = 1.9). The most common surgeries were abdominal (59%) and orthopedic (20%). The mean SPID12 was 36.0 (standard error of the mean = 2.2); mean scores were similar, regardless of age, sex, race, and BMI. From baseline, mean pain intensity decreased significantly starting 30 minutes postdose, and mean pain relief increased significantly starting 15 minutes postdose, remaining relatively stable through 12 hours (P < 0.001 at each time point). Four (3%) patients discontinued due to inadequate analgesia, and 45 (32%) patients had one or more adverse events that were considered possibly or probably related to the study drug. Mean plasma sufentanil concentrations were generally similar regardless of age, sex, BMI, or organ impairment status.

Conclusions

SST 30 mcg was effective and well tolerated for the management of moderate-to-severe acute postoperative pain.

Intravenous Oxycodone Versus Other Intravenous Strong Opioids for Acute Postoperative Pain Control: A Systematic Review of Randomized Controlled Trials

Introduction

Optimal pain management is crucial to the postoperative recovery process. We aimed to evaluate the efficacy and safety of intravenous oxycodone with intravenous fentanyl, morphine, sufentanil, pethidine, and hydromorphone for acute postoperative pain.

Methods

A systematic literature search of PubMed, Cochrane Library, and EMBASE databases was performed for randomized controlled trials published from 2008 through 2017 (inclusive) that evaluated the acute postoperative analgesic efficacy of intravenous oxycodone against fentanyl, morphine, sufentanil, pethidine, and hydromorphone in adult patients (age ≥ 18 years). Outcomes examined included analgesic consumption, pain intensity levels, side effects, and patient satisfaction.

Results

Eleven studies were included in the review; six compared oxycodone with fentanyl, two compared oxycodone with morphine, and three compared oxycodone with sufentanil. There were no eligible studies comparing oxycodone with pethidine or hydromorphone. Overall, analgesic consumption was lower with oxycodone than with fentanyl or sufentanil. Oxycodone exhibited better analgesic efficacy than fentanyl and sufentanil, and comparable analgesic efficacy to morphine. In terms of safety, there was a tendency towards more side effects with oxycodone than with fentanyl, but the incidence of side effects with oxycodone was comparable to morphine and sufentanil. Where patient satisfaction was evaluated, higher satisfaction levels were observed with oxycodone than with sufentanil and comparable satisfaction was noted when comparing oxycodone with fentanyl. Patient satisfaction was not evaluated in the studies comparing oxycodone with morphine.

Conclusions

Our findings suggest that intravenous oxycodone provides better analgesic efficacy than fentanyl and sufentanil, and comparable efficacy to morphine with less adverse events such as sedation. No studies comparing intravenous oxycodone with pethidine or hydromorphone were identified in this review. Better alignment of study methodologies for future research in this area is recommended to provide the best evidence base for a meta-analysis.

Funding

Mundipharma Singapore Holding Pte Ltd, Singapore.

Electronic supplementary material

The online version of this article (10.1007/s40122-019-0122-4) contains supplementary material, which is available to authorized users.

Perioperative intravenous ketamine for acute postoperative pain in adults

BACKGROUND

Inadequate pain management after surgery increases the risk of postoperative complications and may predispose for chronic postsurgical pain. Perioperative ketamine may enhance conventional analgesics in the acute postoperative setting.

OBJECTIVES

To evaluate the efficacy and safety of perioperative intravenous ketamine in adult patients when used for the treatment or prevention of acute pain following general anaesthesia.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to July 2018 and three trials registers (metaRegister of controlled trials, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP)) together with reference checking, citation searching and contact with study authors to identify additional studies.

SELECTION CRITERIA

We sought randomised, double-blind, controlled trials of adults undergoing surgery under general anaesthesia and being treated with perioperative intravenous ketamine. Studies compared ketamine with placebo, or compared ketamine plus a basic analgesic, such as morphine or non-steroidal anti-inflammatory drug (NSAID), with a basic analgesic alone.

DATA COLLECTION AND ANALYSIS

Two review authors searched for studies, extracted efficacy and adverse event data, examined issues of study quality and potential bias, and performed analyses. Primary outcomes were opioid consumption and pain intensity at rest and during movement at 24 and 48 hours postoperatively. Secondary outcomes were time to first analgesic request, assessment of postoperative hyperalgesia, central nervous system (CNS) adverse effects, and postoperative nausea and vomiting. We assessed the evidence using GRADE and created a 'Summary of findings' table.

MAIN RESULTS

We included 130 studies with 8341 participants. Ketamine was given to 4588 participants and 3753 participants served as controls. Types of surgery included ear, nose or throat surgery, wisdom tooth extraction, thoracotomy, lumbar fusion surgery, microdiscectomy, hip joint replacement surgery, knee joint replacement surgery, anterior cruciate ligament repair, knee arthroscopy, mastectomy, haemorrhoidectomy, abdominal surgery, radical prostatectomy, thyroid surgery, elective caesarean section, and laparoscopic surgery. Racemic ketamine bolus doses were predominantly 0.25 mg to 1 mg, and infusions 2 to 5 µg/kg/minute; 10 studies used only S-ketamine and one only R-ketamine. Risk of bias was generally low or uncertain, except for study size; most had fewer than 50 participants per treatment arm, resulting in high heterogeneity, as expected, for most analyses. We did not stratify the main analysis by type of surgery or any other factor, such as dose or timing of ketamine administration, and used a non-stratified analysis.Perioperative intravenous ketamine reduced postoperative opioid consumption over 24 hours by 8 mg morphine equivalents (95% CI 6 to 9; 19% from 42 mg consumed by participants given placebo, moderate-quality evidence; 65 studies, 4004 participants). Over 48 hours, opioid consumption was 13 mg lower (95% CI 10 to 15; 19% from 67 mg with placebo, moderate-quality evidence; 37 studies, 2449 participants).Perioperative intravenous ketamine reduced pain at rest at 24 hours by 5/100 mm on a visual analogue scale (95% CI 4 to 7; 19% lower from 26/100 mm with placebo, high-quality evidence; 82 studies, 5004 participants), and at 48 hours by 5/100 mm (95% CI 3 to 7; 22% lower from 23/100 mm, high-quality evidence; 49 studies, 2962 participants). Pain during movement was reduced at 24 hours (6/100 mm, 14% lower from 42/100 mm, moderate-quality evidence; 29 studies, 1806 participants), and 48 hours (6/100 mm, 16% lower from 37 mm, low-quality evidence; 23 studies, 1353 participants).Results for primary outcomes were consistent when analysed by pain at rest or on movement, operation type, and timing of administration, or sensitivity to study size and pain intensity. No analysis by dose was possible. There was no difference when nitrous oxide was used. We downgraded the quality of the evidence once if numbers of participants were large but small-study effects were present, or twice if numbers were small and small-study effects likely but testing not possible.Ketamine increased the time for the first postoperative analgesic request by 54 minutes (95% CI 37 to 71 minutes), from a mean of 39 minutes with placebo (moderate-quality evidence; 31 studies, 1678 participants). Ketamine reduced the area of postoperative hyperalgesia by 7 cm² (95% CI -11.9 to -2.2), compared with placebo (very low-quality evidence; 7 studies 333 participants). We downgraded the quality of evidence because of small-study effects or because the number of participants was below 400.CNS adverse events occurred in 52 studies, while 53 studies reported of absence of CNS adverse events. Overall, 187/3614 (5%) participants receiving ketamine and 122/2924 (4%) receiving control treatment experienced an adverse event (RR 1.2, 95% CI 0.95 to 1.4; high-quality evidence; 105 studies, 6538 participants). Ketamine reduced postoperative nausea and vomiting from 27% with placebo to 23% with ketamine (RR 0.88, 95% CI 0.81 to 0.96; the number needed to treat to prevent one episode of postoperative nausea and vomiting with perioperative intravenous ketamine administration was 24 (95% CI 16 to 54; high-quality evidence; 95 studies, 5965 participants).

AUTHORS' CONCLUSIONS

Perioperative intravenous ketamine probably reduces postoperative analgesic consumption and pain intensity. Results were consistent in different operation types or timing of ketamine administration, with larger and smaller studies, and by higher and lower pain intensity. CNS adverse events were little different with ketamine or control. Perioperative intravenous ketamine probably reduces postoperative nausea and vomiting by a small extent, of arguable clinical relevance.

Oxycodone versus sufentanil in adult patient-controlled intravenous analgesia after abdominal surgery: A prospective, randomized, double-blinded, multiple-center clinical trial

BACKGROUND

A randomized controlled trial was performed to compare analgesic effects and adverse effects of oxycodone and sufentanil in patient-controlled intravenous analgesia (PCIA) after abdominal surgery under general anesthesia.

METHODS

Adult patients undergoing elective abdominal surgery were randomly allocated into oxycodone and sufentanil groups according to the randomization sequence. Study personnel, health-care team members, and patients were masked to the group assignment throughout the study period. Oxycodone (0.1 mg/kg for endoscopy; 0.15 mg/kg for laparotomy) or sufentanil (0.1 μg/kg for endoscopy; 0.15 μg/kg for laparotomy) was administrated at the end of surgeries. Postoperative pain was controlled using PCIA. Bolus dose was 2 mg and 2 μg for oxycodone and sufentanil group, respectively. The lockout time was 5 minutes for all patients, and there was no background infusion for oxycodone group, whereas 0.02 μg/kg/h background infusion was administrated in sufentanil group. The primary outcomes were the total analgesic doses in PCIA, effective bolus times, the length of first bolus since patients returning to ward from postanesthesia care unit (PACU), rescue analgesic rate in PACU, numeric rating scales, functional activity scores, and patients' satisfaction scores.

RESULTS

A total of 200 patients were screened, and 175 patients were enrolled. Patients were randomly assigned to oxycodone (n = 87) and sufentanil (n = 88) groups. Both oxycodone and sufentanil PCIA provided adequate postoperative pain relief. Patients in oxycodone group showed a shorter consciousness recovery time after surgery. The major adverse effect in patients from oxycodone group was nausea/vomiting, whereas multiple adverse complications including nausea/vomiting, pruritus, and respiratory depression were observed in patients from sufentanil group. Patients from oxycodone group showed significantly reduced analgesic drug consumption (calculated as equivalent dose of morphine), functional activity scores, and patient satisfaction scores.

DISCUSSION

Compared with sufentanil PCIA, oxycodone PCIA showed better analgesic effects, lower incidence of adverse complications, and less analgesic drug consumption during postoperative pain management.

Comparison of different methods of postoperative analgesia after thoracotomy-a randomized controlled trial

Background

Continuous thoracic epidural analgesia (TEA) is a preferred method of postoperative analgesia in thoracic surgery. Intravenous patient-controlled analgesia (IVPCA) may be an effective alternative. One of the most commonly used opioids in PCA is morphine. It has high antinociceptive efficacy but is associated with many adverse events. Oxycodone can be an alternative. A small number of scientific reports comparing morphine and oxycodone in PCA for the treatment of acute postoperative pain after thoracotomy was the reason to conduct this study.

Methods

Prospective, randomised, observational study. In total of 99 patients scheduled for elective thoracotomy were randomized into three study groups. TEA group received continuous TEA as a method of postoperative pain management, morphine (MF) group received morphine IVPCA, and morphine (OXY) group oxycodone IVPCA. For 48 hours' hemodynamic parameters, level of pain, sedation and the need for rescue analgesia were monitored. After 48 hours' patients were asked about their satisfaction with pain treatment using Likert scale and assessment of opioid related adverse events via overall benefit of analgesia score (OBAS).

Results

The level of pain in visual analogic score (VAS) and Prince Henry Hospital Pain Score (PHHPS) scales was significantly lower in TEA group with no significant difference between groups MF and OXY. Using morphine in PCA was associated with a significantly higher likelihood of need of rescue analgesia. The level of sedation in Ramsay scale was significantly higher in MF compared to OXY and TEA group. There were no significant differences between groups in OBAS scale. TEA group was characterized by the highest degree of patient satisfaction.

Conclusions

TEA provided superior anaesthesia compared to PCA in our study group. Use of PCA oxycodone in postoperative pain management after open thoracotomy provides similar nociception control compared to morphine but is associated with less sedation and patients using oxycodone IVPCA require smaller doses of rescue analgesia compared to systemic morphine IVPCA.

Opioids and the Blood-Brain Barrier: A Dynamic Interaction with Consequences on Drug Disposition in Brain

Background:

Opioids are widely used in pain management, acting via opioid receptors and/or Toll-like receptors (TLR) present at the central nervous system (CNS). At the blood-brain barrier (BBB), several influx and efflux transporters, such as the ATP-binding cassette (ABC)

P-glycoprotein (P-gp, ABCB1), Breast Cancer Resistance Protein (BCRP, ABCG2) and multidrug resistance-associated proteins (MRP, ABCC) transporters, and solute carrier transporters (SLC), are responsible for the transport of xenobiotics from the brain into the bloodstream or vice versa.

Objective:

ABC transporters export several clinically employed opioids, altering their neuro-

pharmacokinetics and CNS effects. In this review, we explore the interactions between opioids

and ABC transporters, and decipher the molecular mechanisms by which opioids can modify their expression at the BBB.

Results:

P-gp is largely implicated in the brain-to-blood efflux of opioids, namely morphine and oxycodone. Long-term ex-posure to morphine and oxycodone has proven to up-regulate the expression of ABC transporters, such as P-gp, BCRP and MRPs, at the BBB, which may lead to increased tolerance to the antinociceptive effects of such drugs. Recent studies uncov-er two mechanisms by which morphine may up-regulate P-gp and BCRP at the BBB: 1) via a glutamate, NMDA-receptor and COX-2 signaling cascade, and 2) via TLR4 activation, subsequent development of neuro-

inflammation, and activation of NF-κB, presumably via glial cells.

Conclusion:

The BBB-opioid interaction can culminate in bilateral consequences, since ABC transporters condition the brain disposition of opioids, while opioids also affect the expression of ABC transporters at the BBB, which may result in increased CNS drug pharmacoresistance.

The Safety and Efficacy of Oxycodone Versus Fentanyl in Percutaneous Microwave Ablation of a Liver Tumour Abutting the Capsule

PURPOSE

The present study compared the safety and efficacy of oxycodone with those of fentanyl under non-intubated general anaesthesia in percutaneous microwave ablation (MWA) of a liver tumour abutting the capsule.

MATERIALS AND METHODS

Thirty-eight patients underwent MWA of liver cancers abutting the capsule. Patients received 0.1 mg/kg oxycodone (O group) or 1 μg/kg fentanyl (F group) prior to the start of ablation. Both groups received continuous infusions of propofol for non-intubated general anaesthesia during ablation. The primary outcomes were the pain scores (11-point numeric rating scale, NRS) within 24 h after MWA. Vital signs, body movement during ablation, and opioid side effects after ablation were recorded. The need for additional analgesics was recorded 24 h after MWA.

RESULTS

The pain NRS scores were lower in the O group than in the F group at 0.5 (P = 0.035), 3 (P = 0.002), and 6 h (P = 0.001) after MWA, and fewer patients required additional analgesics in the O group (6 of 20 vs. 13 of 18, P = 0.022) within 24 h. The average 24-h dose of dezocine was 5.5 ± 4.1 mg in the F group and 2.1 ± 3.3 mg in the O group (P = 0.008). A significant reduction in the respiratory rate (P = 0.020) and more body movements were observed in the F group (P = 0.027) during ablation with non-intubated general anaesthesia. No differences in post-operative nausea and vomiting (PONV) were observed between the two groups, but dizziness occurred significantly more often in the O group (P = 0.033). No significant differences in other vital signs were observed before, during, and after the procedure.

CONCLUSIONS

Oxycodone provides better analgesia and reduces post-operative opioid consumption without significant respiratory or hemodynamic instability.

Comparison of the effects of oxycodone versus fentanyl on airway reflex to tracheal extubation and postoperative pain during anesthesia recovery after laparoscopic cholecystectomy: A double-blind, randomized clinical consort study

BACKGROUND

Fentanyl has been suggested to be effective for controlling airway and hemodynamic responses to tracheal extubation. This study was performed to compare the effects of oxycodone and fentanyl on airway and hemodynamic responses and postoperative pain during the recovery period in patients undergoing laparoscopic cholecystectomy.

METHODS

Ninety patients aged 18 to 65 years were randomly allocated to 1 of 3 groups: fentanyl, oxycodone, and control. Coughing responses (incidence and severity), hemodynamic responses during the recovery period, and acute postoperative pain were assessed.

RESULTS

The incidence of cough was decreased in the fentanyl and oxycodone groups compared with that in the control group at the points of awareness and extubation, and no significant difference was observed between the 2 treatment groups. Severe cough response was decreased in the fentanyl and oxycodone groups compared with that in the control group at the point of extubation, and no significant change was observed in cough severity between the 2 treatment groups. Postoperative pain scores were lower in the fentanyl and oxycodone groups than those in the control group at 5 and 30 minutes postoperatively, and no significant difference was observed between the 2 treatment groups. Hemodynamic responses did not differ among the 3 groups during the recovery period.

CONCLUSION

Oxycodone treatment before tracheal extubation reduced cough response and was as effective as fentanyl treatment for improving extubation quality. Furthermore, single boluses of fentanyl and oxycodone showed equal effectiveness in attenuating acute postoperative pain in patients undergoing laparoscopic cholecystectomy.

The opioid epidemic: a central role for the blood brain barrier in opioid analgesia and abuse

Opioids are currently the primary treatment method used to manage both acute and chronic pain. In the past two to three decades, there has been a surge in the use, abuse and misuse of opioids. The mechanism by which opioids relieve pain and induce euphoria is dependent on the drug crossing the blood-brain barrier and accessing the central nervous system. This suggests the blood brain barrier plays a central role in both the benefits and risks of opioid use. The complex physiological responses to opioids that provide the benefits and drive the abuse also needs to be considered in the resolution of the opioid epidemic.

Intravenous Oxycodone versus Intravenous Morphine in Cancer Pain: A Randomized, Open-Label, Parallel-Group, Active-Control Study

Objective

To compare efficacy and safety of intravenous continuous infusion of oxycodone with morphine in patients with cancer pain.

Methods

A 5-day, randomized, open-label, exploratory study at 6 sites in the Republic of Korea. Sixty-six adults aged ≥19 years with moderate-to-severe cancer pain (Numeric Rating Scale [NRS] ≥ 4) were enrolled. The study group received intravenous (IV) oxycodone, and the comparator group received IV morphine which were titrated depending on pain intensity. The efficacy endpoint is change in average NRS score from baseline to Day 5. Other assessments included worst, current, and average pain intensity; patient satisfaction; medication dose; and adverse events.

Results

Both groups achieved >50% reduction in average pain intensity: from “moderate” at baseline (oxycodone versus morphine: 6.0 ± 1.8 versus 5.9 ± 1.4) to “mild” at Day 5 (2.5 ± 1.8 versus 2.8 ± 1.6). While this reduction was similar between groups (3.5 ± 2.2 versus 3.1 ± 1.8, P value = 0.562), oxycodone achieved faster pain relief (average pain: 3.0 ± 1.6 versus 3.9 ± 1.6, P value = 0.020) on Day 2 and significant NRS reductions for worst pain on Day 2 (P value = 0.045) and current pain on Day 2 (P value = 0.035) and Day 5 (P value = 0.020) compared to morphine. Patient satisfaction, adverse events, and adverse drug reactions were similar for both groups.

Conclusions

For Asian patients with cancer pain, IV oxycodone is faster acting and showed similar analgesic efficacy and safety profiles as IV morphine. This trial is registered with Clinicaltrials.gov NCT02660229.

The Effectiveness of Intravenous Oxycodone in the Treatment of Acute Postoperative Pain: A Systematic Review

PURPOSE

Intravenous (IV) opioids are administered for management of acute postoperative pain in the postanesthesia care unit. The benefits of parenteral oxycodone for acute pain management are understudied. The purpose of this review was to evaluate the effectiveness of IV oxycodone for acute postoperative pain.

DESIGN

A systematic review of quantitative studies using the Joanna Briggs Institute approach.

METHODS

A search for randomized controlled trials was conducted, revealing 314 potentially relevant studies. These were compared with the inclusion criteria. Those that met these criteria were critically appraised.

FINDINGS

Participants (N = 506) in eight trials were included in this review. Four studies supported the use of IV oxycodone as patient-controlled analgesia and IV bolus. The remaining studies showed equipotent effects between oxycodone and control. Higher incidences of adverse effects were associated with IV oxycodone.

CONCLUSIONS

IV oxycodone can be considered as effective analgesia for acute postoperative pain with careful regards to its adverse effects.

Analgesic efficacy and safety of epidural oxycodone in patients undergoing total hip arthroplasty: a pilot study

BACKGROUND AND OBJECTIVES

Oxycodone is poorly studied as an adjuvant to central blockades. The aim of this pilot study was to assess the efficacy and safety of oxycodone hydrochloride in epidural blockade among patients undergoing total hip arthroplasty (THA).

PATIENTS AND METHODS

In 11 patients (American Society of Anesthesiologists physical status classification system II/III, age range: 59-82 years), THA was conducted with an epidural blockade using 15 mL 0.25% bupivacaine (37.5 mg) with 5 mg oxycodone hydrochloride and sedation with propofol infusion at a dose of 3-5 mg/kg/h. After the surgery, patients received ketoprofen at a dose of 100 mg twice daily. In the first 24 hours postoperative period, pain was assessed by numerical rating scale at rest and on movement; adverse effects (AEs) were recorded; and plasma concentrations of oxycodone, noroxycodone, and bupivacaine were measured.

RESULTS

The administration of epidural oxycodone at a dose of 5 mg in patients undergoing THA provided analgesia for a mean time of 10.3±4.89 h. In one patient, mild pruritus was observed. Oxycodone did not evoke other AEs. Plasma concentrations of oxycodone while preserving analgesia were >2.9 ng/mL. Noroxycodone concentrations in plasma did not guarantee analgesic effect.

CONCLUSION

The administration of epidural oxycodone at a dose of 5 mg prolongs the analgesia period to ~10 hours in patients after THA. Oxycodone may evoke pruritus. A 5 mg dose of oxycodone hydrochloride used in an epidural blockade seems to be a safe drug in patients after THA.

Comparison of the analgesic effect of patient-controlled oxycodone and fentanyl for pain management in patients undergoing colorectal surgery

Oxycodone is a μ-opioid receptor agonist and is generally indicated for the relief of moderate to severe pain. The aim of this study was to compare the analgesic efficacy of patient-controlled oxycodone and fentanyl for postoperative pain in patients undergoing colorectal surgery. Patients scheduled to undergo elective colorectal surgery (n=82) were allocated to receive oxycodone (n=41, concentration of 1 mg/mL) or fentanyl (n=41, concentration of 15 μg/mL) for postoperative pain management. After the operation, pain using a numerical rating scale (NRS), delivery to demand ratio, infused dose of patient-controlled analgesia (PCA), side effects, and sedation levels were evaluated. Median (25%-75%) cumulative PCA dose of oxycodone group at 48 hours (66.9, 58.4-83.7 mL) was significantly less than that of fentanyl group (80.0, 63.4-103.3 mL, P=.037). Six hours after surgery, the mean (SD) NRS scores of the oxycodone and fentanyl groups were 6.2 (2.4) and 6.8 (1.9), respectively (P=.216). The mean equianalgesic potency ratio of oxycodone to fentanyl was 55:1. The groups did not differ in postoperative nausea, vomiting, and level of sedation. Patient-controlled oxycodone provides similar effects for pain relief compared to patient-controlled fentanyl in spite of less cumulative PCA dose. Based on these results, oxycodone can be a useful alternative to fentanyl for PCA in patients after colorectal surgery.

Revisiting Oxycodone Analgesia: A Review and Hypothesis

Oxycodone, a semisynthetic opioid analgesic, is widely used in clinical practice. Oxycodone and morphine seem to be equally effective and equipotent; however, morphine is 10 times more potent than oxycodone when given epidurally. This article provides an updated review of the basic pharmacology of oxycodone with a special focus on pharmacokinetic/pharmacodynamics properties. The controversy regarding oxycodone-mediated effects for visceral pain via agonism and the possible role of peripheral opioid analgesia are discussed in the present investigation in an attempt to propose a plausible explanation to the perplexing question of oxycodone analgesia.

Oxycodone versus fentanyl for intravenous patient-controlled analgesia after laparoscopic supracervical hysterectomy: A prospective, randomized, double-blind study

BACKGROUND

Oxycodone, a semisynthetic thebaine derivative opioid, is widely used for the relief of moderate to severe pain. The aim of this study was to compare the efficacy and side effects of oxycodone and fentanyl in the management of postoperative pain by intravenous patient-controlled analgesia (IV-PCA) in patients who underwent laparoscopic supracervical hysterectomy (LSH).

METHODS

The 127 patients were randomized to postoperative pain treatment with either oxycodone (n = 64, group O) or fentanyl group (n = 63, group F). Patients received 7.5 mg oxycodone or 100 μg fentanyl with 30-mg ketorolac at the end of anesthesia followed by IV-PCA (potency ratio 75:1) for 48 hours postoperatively. A blinded observer assessed postoperative pain based on the numerical rating scale (NRS), infused PCA dose, patient satisfaction, sedation level, and side effects.

RESULTS

Accumulated IV-PCA consumption in group O was less (63.5 ± 23.9 mL) than in group F (85.3 ± 2.41 mL) during the first 48 hours postoperatively (P = 0.012). The NRS score of group O was significantly lower than that of group F at 4 and 8 hours postoperatively (P < .001); however, the incidence of postoperative nausea and vomiting (PONV), dizziness, and drowsiness was significantly higher in group O than in group F. Patient satisfaction was lower in group O than in group F during the 48 hours after surgery (P < 0.001).

CONCLUSIONS

Oxycodone IV-PCA (potency ratio 1:75) provided superior analgesia to fentanyl IV-PCA after LSH; however, the higher incidence of side effects, including PONV, dizziness, and drowsiness, suggests that the doses used in this study were not equipotent.

Optimal dose of intravenous oxycodone for attenuating hemodynamic changes after endotracheal intubation in healthy patients: A randomized controlled trial

BACKGROUND

Intravenous oxycodone has been used as an adjunct to anesthetic agents. This study aimed to assess the optimal dose of intravenous oxycodone for the attenuation of the hemodynamic responses to laryngoscopy and endotracheal intubation.

METHODS

A prospective, randomized, double-blind study was conducted. Ninety-five patients were randomly divided into 5 groups based on the oxycodone dose: 0, 0.05, 0.1, 0.15, 0.2 mg/kg. After administering the assigned dose of intravenous oxycodone, anesthesia was induced with thiopental. Heart rate (HR) and blood pressure (BP) were measured at baseline, before intubation, and 1, 2, and 3 minutes after intubation. The percentage increase of BP was calculated as (highest BP after intubation - baseline BP)/baseline BP × 100 (%). The percentage increase of HR was calculated in same formula as above. Hypertension was defined as a 15% increase of systolic BP from baseline, and probit analysis was conducted.

RESULTS

Hemodynamic data from 86 patients were analyzed. The percentage increase of mean arterial pressure after intubation in groups 0.05, 0.1, 0.15, and 0.2 was significantly different from that in the control (P < 0.001). For HR, the percentage increase was lower than control group when oxycodone was same or more than 0.1 mg/kg (P < 0.05). Using probit analysis, the 95% effective dose (ED95) for preventing hypertension was 0.159 mg/kg (95% confidence interval [CI], 0.122-0.243). In addition, ED50 was 0.020 mg/kg (95% CI, -0.037 to 0.049). However, oxycodone was not effective for maintaining the HR in our study dosage. There were no significant differences in the incidence of hypotension during induction between groups.

CONCLUSIONS

Using 0.1 mg/kg of intravenous oxycodone is sufficient to attenuate the increase of BP and HR during induction period in healthy patients. The ED95, which was 0.159 mg/kg, can be useful to adjust the dosage of IV oxycodone for maintain stable BP during induction of general anesthesia.

Multimodal Analgesia, Current Concepts, and Acute Pain Considerations

PURPOSE OF REVIEW

Management of acute pain following surgery using a multimodal approach is recommended by the American Society of Anesthesiologists whenever possible. In addition to opioids, drugs with differing mechanisms of actions target pain pathways resulting in additive and/or synergistic effects. Some of these agents include alpha 2 agonists, NMDA receptor antagonists, gabapentinoids, dexamethasone, NSAIDs, acetaminophen, and duloxetine.

RECENT FINDINGS

Alpha 2 agonists have been shown to have opioid-sparing effects, but can cause hypotension and bradycardia and must be taken into consideration when administered. Acetaminophen is commonly used in a multimodal approach, with recent evidence lacking for the use of IV over oral formulations in patients able to take medications by mouth. Studies involving gabapentinoids have been mixed with some showing benefit; however, future large randomized controlled trials are needed. Ketamine is known to have powerful analgesic effects and, when combined with magnesium and other agents, may have a synergistic effect. Dexamethasone reduces postoperative nausea and vomiting and has been demonstrated to be an effective adjunct in multimodal analgesia. The serotonin-norepinephrine reuptake inhibitor, duloxetine, is a novel agent, but studies are limited and further evidence is needed. Overall, a multimodal analgesic approach should be used when treating postoperative pain, as it can potentially reduce side effects and provide the benefit of treating pain through different cellular pathways.

Opioid Conversions in Acute Care

Objective:

To discuss the historical basis and limitations of opioid conversion tables, review the relevant literature, and establish an evidence-based equianalgesic dose ratio (EDR) table for performing conversions in the acute care setting.

Data Sources:

Articles were identified through searches of MEDLINE (1966–January 2007) using the key words opioid, tolerance, conversion, dose, equianalgesic, equipotent, acute care, morphine, hydromorphone, fentanyl, methadone, and oxycodone. Additional references were located through a review of the bibliographies of articles cited and references cited in conversion tables.

Study Selection and Data Extraction:

All data sources identified were evaluated, and all information deemed relevant was included, with the exception of case series and case reports when higher level evidence was available.

Data Synthesis:

Opioid conversion tables are published in major textbooks, medical references, national guidelines, and review articles. Some conversion tables do not accurately reflect the dose ratios for which evidence is available. There is marginal evidence-based clinical data to support the dose ratios cited in these tables, particularly in the acute care setting where the clinical status of patients often changes rapidly. The barriers when performing route and opioid-to-opioid conversions in the acute care setting are formidable, but EDRs are provided, based on the best available evidence.

Conclusions:

In the acute care setting, calculation of dose ratios for opioids, based solely on opioid conversion tables, is an oversimplification of pain management, with a potential for adverse consequences. The calculation of EDRs is one step in an interdisciplinary process that must take into account patient- and institution-specific factors.

Comparison of hemodynamic response to tracheal intubation and postoperative pain in patients undergoing closed reduction of nasal bone fracture under general anesthesia: a randomized controlled trial comparing fentanyl and oxycodone

Background

The present study aimed to compare the intravenous bolus effect of oxycodone and fentanyl on hemodynamic response after endotracheal intubation and postoperative pain in patients undergoing closed reduction of nasal bone fracture.

Methods

In this prospective randomized double-blinded study, 64 patients undergoing closed reduction of nasal bone fracture were randomized into one of two groups: the fentanyl group (Group F) or the oxycodone group (Group O). Each drug (fentanyl 2 mcg/kg in Group F and oxycodone 0.2 mg/kg in Group O) was administered prior to the induction of general anesthesia. Hemodynamic changes after endotracheal intubation and postoperative pain were then measured in both groups.

Results

There was no significant difference in the change in mean arterial pressure and heart rate between pre-induction and post-intubation in both Groups F and O (P > 0.05). Postoperative pain in Group O was milder than that in Group F (P < 0.001); however, time to awakening from the end of operation was shorter in Group F (P = 0.012).

Conclusion

In patients undergoing closed reduction of nasal bone fracture, oxycodone attenuates hemodynamic response to endotracheal intubation similar to fentanyl. However, oxycodone is more effective than fentanyl in improving postoperative pain.

Trial registration

Clinical Research Information Service (Trial registry number: KCT0001153) on 3 July, 2014

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-016-0279-x) contains supplementary material, which is available to authorized users.

A Comparison of Oxycodone and Alfentanil in Intravenous Patient-Controlled Analgesia with a Time-Scheduled Decremental Infusion after Laparoscopic Cholecystectomy

Background. Oxycodone, a semisynthetic opioid, has been widely used for acute and chronic pain. Objectives. The aim of this study was to compare the analgesic and adverse effects of oxycodone and alfentanil on postoperative pain after laparoscopic cholecystectomy. Methods. This was a prospective, randomized, double-blind study. A total of 82 patients undergoing laparoscopic cholecystectomy were randomly assigned to receive either oxycodone or alfentanil using intravenous patient-controlled analgesia (PCA). PCA was administered as a time-scheduled decremental continuous infusion based on lean body mass for 48 hours postoperatively. Patients were assessed for pain with a visual analogue scale (VAS), the cumulative PCA dose, adverse effects, sedation level at 1, 4, 8, 16, 24, and 48 hours postoperatively, and satisfaction during the postoperative 48 hours. Results. There were no significant differences (p < 0.05) between the two groups in VAS score, cumulative PCA dose, adverse effects, sedation level at 1, 4, 8, 16, 24, and 48 hours postoperatively, and satisfaction during the postoperative 48 hours. Conclusions. Our data showed that the analgesic and adverse effects of oxycodone and alfentanil were similar. Therefore, oxycodone may be a good alternative to alfentanil for pain management using intravenous PCA after laparoscopic cholecystectomy when used at a conversion ratio of 10 : 1. This trial is registered with KCT0001962.

Perspectives on Intravenous Oxycodone for Control of Postoperative Pain

Intravenous (IV) analgesia has particular advantages in the immediate postoperative period. For example, IV administration results in a faster onset of pain relief and results in more predictable pharmacokinetics than does administration by other routes. It also allows for convenient dosing before or during surgery, permitting the initiation of effective analgesia in the early phase of the postoperative period. In addition, when patients are able to tolerate oral intake, they can be switched from IV to oral dosing based on maintaining the predictable analgesia established by the IV route. IV morphine is widely used for the control of postoperative pain, but there is a trend toward the use of oxycodone. Oxycodone (which may be mediated partly through kappa- as well as mu-opioid receptors) offers several potential advantages. Published studies comparing IV oxycodone to other IV opioids for postsurgical pain report that oxycodone is a safe and effective analgesic. Some studies show that IV oxycodone may be associated with greater pain control, fewer or less severe adverse events, and faster onset of action, although the results are not consistent across all studies. Oxycodone has been reported to be safe in the geriatric and other special populations when adequate clinical adjustments are made. Thus, the clinical reports and oxycodone's pharmacologic profile make intravenous oxycodone a potentially important "new" old drug for postoperative pain control.

Efficacy and tolerability of oxycodone versus fentanyl for intravenous patient-controlled analgesia after gastrointestinal laparotomy: A prospective, randomized, double-blind study

BACKGROUND

It has been suggested that oxycodone is effective in relieving acute postoperative pain. The aim of this study was to investigate the efficacy and tolerability of oxycodone (O) versus fentanyl (F), and the adequate potency ratio of oxycodone and fentanyl in patients with intravenous patient-controlled analgesia after gastric laparotomy.

METHODS

In this double-blinded, randomized, controlled study, 60 patients undergoing elective gastric laparotomy were allocated to receive either oxycodone or fentanyl for postoperative intravenous patient-controlled analgesia (potency ratio 60:1). The patients received ketorolac 60 mg before the end of anesthesia and then continued with patient-controlled analgesia for 48 hours postsurgery. Pain severity, side effects and respiration rate were recorded 30 minutes, 3, 6, 12, 24, and 48 hours after the surgery. Cumulative opioid requirements and patient satisfaction were also measured.

RESULTS

The median consumption more than 48 hours after operation of oxycodone was 50 mg (range: 40.0-62.4 mg) and fentanyl was 0.8 mg (range: 0.6-1.1 mg), and the percentage of patients requiring rescue medication was not statistically significant. Numeric rating scores at rest and upon movement were significantly lower in group O than in F (P < 0.05). Whereas the incidences of adverse events were similar between the groups (33.3% vs 27.6%, P = 0.64), a significant higher sedation scores were found in patients given fentanyl at 30 minutes after the surgery (P = 0.04).

CONCLUSION

Oxycodone was comparable to fentanyl in the relief of postoperative pain following gastric laparotomy. Oxycodone not only provides better postoperative pain relief and less sedation, but also there was a tendency toward more side effects with oxycodone.

A new therapeutic option for postoperative pain management with oxycodone HCI injection

Fentanyl is the most commonly used opioid analgesic in intravenous patient-controlled analgesia (IV PCA) in Korea. IV oxycodone was approved for postoperative IV PCA by the Ministry of Food and Drug Safety of Korea in 2013. The approved dosage regimen for postoperative pain relief with IV oxycodone is IV bolus loading of 2 mg followed by PCA composed of demand boluses of 1 mg and no background infusion with an oxycodone concentration of 1 mg/ml. However, a simulation study indicated that the minimum effective analgesic concentration (MEAC, as indicated by relief of pain by administering rescue analgesics) of oxycodone was reached most quickly with a higher loading dose of 0.1 mg/kg and IV PCA with background infusion. Oxycodone is a therapeutic option as an analgesic for postoperative pain management. It is necessary to reduce the analgesic dose of oxycodone in elderly patients because metabolic clearance decreases with age.