Oxycodone for the treatment of postoperative pain

Patient Controlled Intravenous Analgesia with Oxycodone or Sufentanil After Hip Surgery: Study Protocol for a Multi-Centered, Randomized Controlled Trial

Background: Patient-controlled intravenous analgesia (PCIA) after hip surgery should be focused on sufficient analgesia, recovery, and the risk of adverse effects. Sufentanil PCIA offers effective analgesia but with obvious side effects. Oxycodone, a semi-synthetic opioid, is reported to have good analgesic effects with fewer adverse effects compared to strong opioids. We hypothesize that in hip surgery, compared with sufentanil PCIA, oxycodone PCIA in an equipotent dose to sufentanil could achieve similar postoperative analgesia while reducing the incidence of adverse effects associated with strong opioids. Methods: This multi-centered, randomized, controlled open-label clinical trial compares the efficacy of oxycodone and sufentanil for PCIA in hip surgery patients. Results: A total of 570 subjects will be randomly allocated in a 1:1 ratio into either the oxycodone group or sufentanil group. The primary outcome is the resting numerical rating scale (NRS) pain scores at 2 h after surgery. The secondary outcomes include the incidence of postoperative nausea and vomiting (PONV), NRS pain scores on movement, complications, mobilization time, length of hospital stay, total in-hospital cost, etc. Conclusions: This trial will provide evidence for the choice of PCIA in hip surgery by comparing the analgesic efficacy and side effects of oxycodone and sufentanil, serving as a foundation for postoperative pain management guidelines and recommendations. Trial Registration: Clinical Trials NCT03685188.

Impact of oxycodone for the treatment of acute postoperative pain in cesarean section: A review

The review aimed to summarize the recent pharmacological and published clinical trials that used oxycodone for pain management after cesarean section (CS). This narrative review is based on published studies in PubMed, EMbase, Web of science, and EBSCO on oxycodone for pain control after CS. Random studies that used oxycodone only or used oxycodone as a major part of a multimodal analgesia regimen were included. Non-English trials, abstract of conference, letters to the editor, animal studies, or studies with insufficient data were excluded. The initial search terms included a combination of free text words and Medical Subject Headings terms. There are 14 clinical trials included and the total number of participants was 1651. These included documents disputed oral oxycodone and patient-controlled intravenous analgesia (PCIA) morphine, compared oral oxycodone and intravenous morphine, investigated sustained-release oral oxycodone and intrathecal morphine, investigated slow release tapentadol and controlled-release oxycodone, investigated ketoprofen, combination of acetaminophen + oxycodone, acetaminophen, and placebo, evaluated oral oxycodone and epidural ropivacaine + sufentanil, evaluated oral oxycodone and PCIA piritramide, evaluated the combination oxycodone + acetaminophen and separately administered oxycodone/acetaminophen, compared the immediate-release oxycodone and controlled-release oxycodone, compared the oral and intravenous oxycodone, disputed PCIA oxycodone or morphine, compared epidural oxycodone and morphine, evaluated PCIA oxycodone, sufentanil or their combination. Oxycodone showed superior or similar postoperative analgesic efficacy compared with other opioids in various administration and reduced the need for rescue medication and side effects. Oxycodone can be successfully used for postoperative analgesia after CS with comparable side effects.

Comparison of oxycodone hydrochloride and flurbiprofen axetil on analgesia in mechanically ventilated patients with respiratory failure in a multicenter study

The design of this study is to compare the effectiveness of two analgesic drugs in the intervention of pain events for patients on mechanical ventilation. 414 patients from three hospitals with respiratory failure requiring mechanical ventilation were randomly assigned to oxycodone hydrochloride or flurbiprofen axetil. The primary endpoints is the difference in the proportion of patients with a Behavioral Pain Scale (BPS) score > 5 within 48 h. The secondary endpoints is to compare the dosage of sedative drugs (midazolam, propofol, dexmedetomidine) and to assess the clinical outcomes such as duration of mechanical ventilation. There was no significant difference in BPS scores between the two groups at enrollment, and BPS scores in oxycodone group were significantly lower than those in flurbiprofen axetil group at 24 and 48 h of enrollment. The proportion of patients with BPS less than 5 points in the Oxycodone hydrochloride group was also significantly lower than that in the flurbiprofen axetil group. For patients with Acute Physiology and Chronic Health Evaluation II (APACHE II) score greater than 10, subgroup analysis showed that the mechanical ventilation time of oxycodone hydrochloride group was significantly lower than that of flurbiprofen axetil group with statistical significance, and the dosage of midazolam was significantly lower than that of flurbiprofen axetil group. The length of ICU stay was significantly lower than that of flurbiprofen axetil group. Oxycodone hydrochloride was more potent than flurbiprofen axetil for analgesia for patients with respiratory failure requiring mechanical ventilation.

Oxycodone attenuates lipopolysaccharide-induced myocardial injury by inhibiting inflammation, oxidation and pyroptosis via Nrf2/HO-1 signalling pathway

Myocardial injury and cardiovascular dysfunction are the most common complications of sepsis, and effective therapeutic candidate is still lacking. This study aims to investigate the protective effect of oxycodone in myocardial injury of lipopolysaccharide-induced sepsis and its related signalling pathways. Wild-type and nuclear factor erythroid 2-related factor 2 (Nrf2)-knockout mice, as well as H9c2 cardiomyocytes cultures treated with lipopolysaccharide (LPS) were used as models of septic myocardial injury. H9c2 cardiomyocytes culture showed that oxycodone protected cells from pyroptosis induced by LPS. Mice model confirmed that oxycodone pretreatment significantly attenuated myocardial pathological damage and improved cardiac function demonstrated by increased ejection fraction (EF) and fractional shortening (FS), as well as decreased cardiac troponin I (cTnI) and creatine kinase isoenzymes MB (CK-MB). Oxycodone also reduced the levels of inflammatory factors and oxidative stress damage induced by LPS, which involves pyroptosis-related proteins including: Nod-like receptor protein 3 (NLRP3), Caspase 1, Apoptosis-associated speck-like protein contain a CARD (ASC), and Gasdermin D (GSDMD). These changes were mediated by Nrf2 and heme oxygenase-1 (HO-1) because Nrf2-knockout mice or Nrf2 knockdown in H9c2 cells significantly reversed the beneficial effect of oxycodone on oxidative stress, inflammatory responses and NLRP3-mediated pyroptosis. Our findings yielded that oxycodone therapy reduces LPS-induced myocardial injury by suppressing NLRP3-mediated pyroptosis via the Nrf2/HO-1 signalling pathway in vivo and in vitro.

Effect of Oxycodone-Based Multimodal Analgesia on Visceral Pain After Major Laparoscopic Gastrointestinal Surgery: A Randomised, Double-Blind, Controlled Trial

Purpose

Oxycodone is a potent μ- and κ-opioid receptor agonist that can relieve both somatic and visceral pain. We assessed oxycodone- vs sufentanil-based multimodal analgesia on postoperative pain following major laparoscopic gastrointestinal surgery.

Methods

In this randomised double-blind controlled trial, 40 adult patients were randomised (1:1, stratified by type of surgery) to receive oxycodone- or sufentanil-based multimodal analgesia, comprising bilateral transverse abdominis plane blocks, intraoperative dexmedetomidine infusion, flurbiprofen axetil, and oxycodone- or sufentanil-based patient-controlled analgesia. The co-primary outcomes were time-weighted average (TWA) of visceral pain (defined as intra-abdominal deep and dull pain) at rest and on coughing during 0-24 h postoperatively, assessed using the numerical rating scale (0-10) with a minimal clinically important difference of 1.

Results

All patients completed the study (median age, 64 years; 65% male) and had adequate postoperative pain control. The mean (SD) 24-h TWA of visceral pain at rest was 1.40 (0.77) in the oxycodone group vs 2.00 (0.98) in the sufentanil group (mean difference=-0.60, 95% CI, -1.16 to -0.03; P=0.039). Patients in the oxycodone group had a significantly lower 24-h TWA of visceral pain on coughing (2.00 [0.83] vs 2.98 [1.26]; mean difference=-0.98, 95% CI, -1.66 to -0.30; P=0.006). In the subgroup analyses, the treatment effect of oxycodone vs sufentanil on the co-primary outcomes did not differ in terms of age (18-65 years or >65 years), sex (female or male), or type of surgery (colorectal or gastric). Secondary outcomes (24-h TWA of incisional and shoulder pain, postoperative analgesic usage, rescue analgesia, adverse events, and patient satisfaction) were comparable between groups.

Conclusion

For patients undergoing major laparoscopic gastrointestinal surgery, oxycodone-based multimodal analgesia reduced postoperative visceral pain in a statistically significant but not clinically important manner.

Trial Registration

Chinese Clinical Trial Registry (ChiCTR2100052085).

Genetic background and sex influence somatosensory sensitivity and oxycodone analgesia in the Hybrid Rat Diversity Panel

Opioid use disorder (OUD) is an ongoing public health concern in the United States, and relatively little work has addressed how genetic background contributes to OUD. Understanding the genetic contributions to oxycodone-induced analgesia could provide insight into the early stages of OUD development. Here, we present findings from a behavioral phenotyping protocol using several inbred strains from the Hybrid Rat Diversity Panel. Our behavioral protocol included a modified "up-down" von Frey procedure to measure inherent strain differences in the sensitivity to a mechanical stimulus on the hindpaw. We also performed the tail immersion assay, which measures the latency to display tail withdrawal in response to a hot water bath. Initial withdrawal thresholds were taken in drug-naïve animals to record baseline thermal sensitivity across the strains. Oxycodone-induced analgesia was measured after administration of oxycodone over the course of 2 h. Both mechanical and thermal sensitivity are shaped by genetic factors and display moderate heritability (h2 = 0.23-0.40). All strains displayed oxycodone-induced analgesia that peaked at 15-30 min and returned to baseline by 2 h. There were significant differences between the strains in the magnitude and duration of their analgesic response to oxycodone, although the heritability estimates were quite modest (h2 = 0.10-0.15). These data demonstrate that genetic background confers differences in mechanical sensitivity, thermal sensitivity, and oxycodone-induced analgesia.

Importance of cytochrome 3A4 and 2D6-mediated drug-drug interactions in oxycodone consumption among older adults hospitalized for hip fracture: a cross-sectional study

Hip fracture is a common injury and represents a major health problem with an increasing incidence. In older adults, opioids such as oxycodone are often preferred to other analgesics such as tramadol because of a lower risk of delirium. Different parameters, such as inhibition of cytochrome P450 (CYP450) 2D6 and/or 3A4, can potentially lead to pharmacokinetic variations of oxycodone representing a risk of adverse drugs effects or lack of drug response. There is a risk of drug-drug interactions involving CYP450 in older adults due to the high prevalence of polypharmacy. This study sought to identify patient characteristics that influence oxycodone administration. A single-center observational study included 355 patients with a hip fracture hospitalized in a geriatric postoperative unit. Composite endpoint based on form, duration, and timing to intake separated patients into three groups: "no oxycodone", "low oxycodone ", and "high oxycodone ". CYP450 interactions were studied based on a composite variable defining the most involved CYP450 pathways between CYP2D6 and CYP3A4. CYP450 interactions with CYP2D6 pathway involved were associated with the risk of "high oxycodone" [odds ratio adjusted on age and the type of hip fracture (OR*) 4.52, 95% confidence interval (CI) 1.39-16.83, p = 0.02)], as well as serum albumin levels (OR* 1.09, 95% CI 1.02-1.17, p = 0.01). Cognitive impairment was negatively associated with the risk of "high oxycodone" (OR* 0.38, 95% CI 0.18-0.77, p = 0.02). This study showed an association between CYP2D6 interactions and higher oxycodone consumption indirectly reflecting the existence of uncontrolled postoperative pain.

Population pharmacokinetics of oxycodone: Premature neonates to adults

BACKGROUND

Oxycodone is used in children and adults for the control of acute postoperative pain. Covariate influences such as age, size, and fat mass on oxycodone pharmacokinetic parameters over the human lifespan are poorly quantified.

METHODS

Pooled oxycodone time-concentration profiles were available from preterm neonates to adults. Data from intravenous, intramuscular, buccal, and epidural formulations were analyzed using nonlinear mixed-effects models. Normal fat mass was used to determine the influence of fat on oxycodone pharmacokinetics. Theory-based allometry was used to scale pharmacokinetic parameters to a 70 kg individual. A maturation function described the increase in clearance in neonates and infants.

RESULTS

There were 237 subjects (24 weeks postmenstrual age to 75 years; 0.44-110 kg) providing 1317 plasma concentrations. A three-compartment model with first-order elimination best described oxycodone disposition. Population parameter estimates were clearance (CL) 48.6 L.h^-1 .70 kg^-1 (CV 71%); intercompartmental clearances (Q2) 220 L.h^-1 .70 kg^-1 (CV 64%); Q3 1.45 L.h^-1 .70 kg^-1 ; volume of distribution in the central compartment (V1) 98.2 L.70 kg^-1 (CV 76%); rapidly equilibrating peripheral compartment (V2) 90.1 L. 70 kg^-1 (CV 76%); slow equilibrating peripheral compartment (V3) 28.9 L.70 kg^-1 . Total body weight was the best size descriptor for clearances and volumes. Absorption halftimes (T_ABS ) were: 1.1 minutes for intramuscular, 70 minutes for epidural, 82 minutes for nasogastric, and 159.6 minutes for buccal administration routes. The relative bioavailability after nasogastric administration was 0.673 with a lag time of 8.7 minutes.

CONCLUSIONS

Clearance matured with age; 8% of the typical adult value at 24 weeks postmenstrual age, 33% in a term neonate and reached 90% of the adult clearance value by the end of the first year of life. Allometric scaling using total body weight was the better size descriptor of oxycodone clearance than fat-free mass.

The Effect of Oxycodone on Post-operative Pain and Inflammatory Cytokine Release in Elderly Patients Undergoing Laparoscopic Gastrectomy

Background: To evaluate the effect of oxycodone on post-operative pain and inflammation in elderly patients undergoing laparoscopic gastrectomy. Methods: Sixty patients who were of both sexes, American Society of Anesthesiologists Physical Status (ASA-PS) Class I or II, over 65 years of age and undergoing an elective laparoscopic radical gastrectomy were randomly divided into two groups: an oxycodone group (Group O) including 20 males and 10 females and a sufentanil group (Group S) including 21 males and 9 females. The post-operative analgesia regimen was as follows: 40 mg of parecoxib sodium and 0.1 mg/kg of oxycodone was intravenously injected into Group O before the abdomen closure, while 40 mg of parecoxib sodium and 0.1 μg/kg of sufentanil was injected intravenously into Group S. Both groups were infiltrated with 20 ml of 1% ropivacaine at the end of the operation. The level of serum IL-6 and IL-10 were assayed immediately at the following timepoints: at the conclusion of surgery (T1), 1 h (T2), 6 h (T3), and 24 h (T4) after the completion of the surgery. The numerical rating scale (NRS), the Ramsay sedation score, analgesic-related adverse events, post-operative pulmonary inflammation events and the post-operative stay were recorded. Results: Compared with Group S, the serum IL-6 concentrations of Group O decreased at T₃ and T₄, while the serum IL-10 concentrations increased (P < 0.05). In Group O, the serum IL-6 concentrations at T₃ and T₄ were lower than those at T₁ (P < 0.05). The incidence of post-operative nausea and vomiting (PONV) and pulmonary inflammation in Group O was lower than that in Group S (P < 0.05). At each time point, the NRS of visceral pain in Group O was lower than that in Group S. At 6 and 24 h after extubation, the NRS of incision pain in Group O was lower than that in Group S (P < 0.05). Conclusion: Oxycodone can regulate the level of inflammatory cytokines and reduce post-operative inflammatory response.

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.

A Scoping Review of Intravenous Opioid Pain Protocols and Their Dose-Time Intervals in the Management of Acute Postoperative Pain in the Postanesthesia Care Unit

PURPOSE

This review aims to explore intravenous opioid pain protocols and their dose-time intervals in managing acute postoperative pain in adults in the postanesthesia care unit (PACU).

DESIGN

A scoping review using a systematic search strategy.

METHODS

Sixteen articles were identified from MEDLINE, CINAHL, PubMed, Embase, and Cochrane specific to the aims.

FINDINGS

The literature demonstrated several variations on dose-time intervals used for opioid pain protocol administration globally. Furthermore, opioid analgesic pain protocols in the PACU appear to be effective in postoperative pain management. However, the literature did not identify optimal time intervals related to dose administration within these protocols.

CONCLUSIONS

Literature gaps were identified regarding the significance of dose-time intervals when using opioid analgesic pain protocols in the PACU.

Oxycodone vs Sufentanil in Patient-Controlled Intravenous Analgesia After Gynecological Tumor Operation: A Randomized Double-Blind Clinical Trial

Background

This study aims to compare analgesic effect and side effects of oxycodone and sufentanil in transition analgesia and patient-controlled intravenous analgesia (PCIA) after gynecological tumor operation under general anesthesia.

Patients and Methods

A prospective, randomized, double-blind research was conducted. Patients undergoing elective gynecological tumor surgery were randomized into four groups: Group S (sufentanil transition analgesia and sufentanil PCIA), Group OS (oxycodone transition analgesia and sufentanil PCIA), Group SO (sufentanil transition analgesia and oxycodone PCIA) and Group O (oxycodone transition analgesia and oxycodone PCIA). The primary outcomes were Numerical Rating Scale (NRS) at rest and coughing, accumulated opioid consumption in PCIA and patients’ satisfaction.

Results

Patients in Group OS and Group O showed shorter time of consciousness recovery and extubation after surgery. Accumulated opioid consumption in PCIA (equal to morphine) in Group SO and Group O was significantly less than that in Group S and Group OS. Patients in Group O showed lower NRS at rest and coughing, but higher patients’ satisfaction 3, 24 and 48 hours after surgery. Patients in Group SO and Group O showed a shorter time of intestinal recovery, first feeding and first-time movement.

Conclusion

Both oxycodone and sufentanil provided adequate pain relief in transitional analgesia and PCIA treatment after surgery. Oxycodone without background infusion showed less analgesic drug consumption and faster recovery than sufentanil with background infusion in PCIA after gynecological tumor operation under general anesthesia.

Preemptive oxycodone is superior to equal dose of sufentanil to reduce visceral pain and inflammatory markers after surgery: a randomized controlled trail

Background

Postoperative visceral pain is common after surgery and previous studies have demonstrated that oxycodone is an effective treatment. In this study, we compared the effects of preemptive oxycodone to equal dose of sufentanil on postoperative pain and serum level of inflammatory factors (TNF-α, IL-6, IL-10) after laparoscopic cholecystectomy.

Methods

Forty patients undergoing laparoscopic cholecystectomy were randomized into preemptive oxycodone group or preemptive sufentanil group.

Patients were given either oxycodone 0.1 mg/kg (oxycodone group, n = 20) or sufentanil 0.1 μg/kg (sufentanil group, n = 20) for preemptive analgesia. We evaluated pain/sedation scores at 0 h, 0.5 h, 2 h, 4 h, 6 h, 8 h and 24 h after surgery and measured serum concentrations of TNF-α, IL-6 and IL-10 before surgery and at 0 h, 6 h and 24 h after surgery.

Results

Twenty patients were recruited in each group. Numerical rating scale (NRS) of visceral pain in the oxycodone group at 2 h when resting (0.5(0,2.75) vs 3(2,4), P = 0.008) and moving (0.5(0,3) vs 3(2.25,4), P = 0.015) and 4 h when moving (2(0,3) vs 3(0,4.75), P = 0.043) after surgery were significantly lower than the sufentanil group. Serum concentrations of TNF-α at 6 h (38.68 ± 10.49 vs 73.02 ± 16.27, P<0.001) and 24 h (43.12 ± 8.40 vs 74.00 ± 21.30, P<0.001) in the oxycodone group were lower than the sufentanil group.

Conclusions

Preemptive oxycodone 0.1 mg/kg administration could effectively suppress visceral pain at 2 h and 4 h after surgery and had lower inflammatory marker, serum TNF-α, level when compared to equal dose of sufentanil.

Trial registration

Clinical trials registration number: ChiCTR-IOR-17013738http://www.chictr.org.cn/showproj.aspx?proj=17346. Date of registration: 6th December 2017.

Population pharmacokinetics of oxycodone in plasma and cerebrospinal fluid after epidural and intravenous administration

Objectives: To establish the first plasma and cerebrospinal fluid (CSF) oxycodone population pharmacokinetic (PopPK) model after epidural (EPI) and intravenous (IV) oxycodone administration. Methods: The study was conducted with 30 female subjects undergoing elective gynecological surgery with epidural analgesia. A parallel single dose of EPI oxycodone with IV placebo (EPI group; n = 18) or IV oxycodone with EPI placebo (IV group; n = 12) was administered. An epidural catheter for drug administration was placed at T12/L1 and a spinal catheter for CSF sampling at L3/4. Plasma and CSF for oxycodone analysis were frequently collected. A PopPK model was built using the NONMEM software package. Results: Plasma and CSF oxycodone concentrations were evaluated using separate central plasma and CSF compartments and separate peripheral plasma and CSF compartments. Epidural space served as a depot compartment with transfer to both the plasma and CSF central compartments. The population parameters for plasma clearance and apparent distribution volumes for central and peripheral compartments for plasma and CSF were 37.4 L/h, 90.2 L, 68.9 L, 0.035 L (fixed based on literature), and 0.039 L, respectively. Conclusion: A PopPK model was developed and found to precisely and accurately describe oxycodone time-concentration data in plasma and CSF.

Effect of Intravenous Oxycodone Versus Sufentanil on the Incidence of Postoperative Nausea and Vomiting in Patients Undergoing Gynecological Laparoscopic Surgery

More than 30% of patients who undergo surgery will experience postoperative nausea and vomiting (PONV) if no prophylactic treatments are used. Although numerous studies have been performed to investigate the factors related to PONV, the effect of perioperative intravenous oxycodone on the incidence of PONV has not been well investigated. In this study, gynecological patients (grade I-II, aged 18-65 years, scheduled to undergo elective gynecological laparoscopic surgery under general anesthesia) were randomized to the oxycodone group or the sufentanil group. In the oxycodone group, patients received intravenous oxycodone for the induction and maintenance of anesthesia, as well as postoperative analgesia, while sufentanil was used in the sufentanil group. The primary outcome variable was the incidence of PONV. As secondary outcomes, time to first PONV, the rating of the most severe PONV, postoperative pain scores at different time points, hemodynamics, and side effects were evaluated. We found that, compared with sufentanil, oxycodone decreased the incidence of PONV by 13.5% (P = .041). The time to first vomiting was longer in the oxycodone group than in the sufentanil group. Postoperative pain scores at different time points and hemodynamics were comparable between the oxycodone and sufentanil groups. We concluded that the incidence of PONV in gynecological patients who underwent laparoscopic surgery was lower when using intravenous oxycodone for anesthesia induction, anesthesia maintenance, and postoperative analgesia than when using intravenous sufentanil. However, oxycodone and sufentanil provided the same stable hemodynamics during surgery and satisfactory postoperative analgesia.

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.

The analgesic efficacy and pharmacokinetics of epidural oxycodone after gynaecological laparotomy: a randomized, double-blind, double-dummy comparison with intravenous administration

AIM

The aim of the present study was to compare the analgesic efficacy of epidural and intravenous (i.v.) oxycodone at the same dose.

METHODS

In this randomized, double-blind, double-dummy clinical trial, 30 women, aged 24-67 years, undergoing elective gynaecological laparotomy, were administrated either i.v. saline and epidural oxycodone 0.1 mg·kg^-1 (EPI group; n = 15) or i.v. oxycodone 0.1 mg·kg^-1 and epidural saline (IV group; n = 15). For multimodal analgesia, patients received i.v. paracetamol and dexketoprofen, and a triple-mixture epidural infusion after the first 4 h postoperatively. The primary outcome was the total dose of i.v. fentanyl for rescue analgesia during the first 4 h postoperatively.

RESULTS

All patients required fentanyl during the first 4 h. The median number of fentanyl doses were three (quartiles 1, 8) in the EPI group and seven (6, 9) in the IV group (mean difference 3.1; 95% confidence interval 0.9, 5.2; P = 0.01). After the first 4 h, the two groups needed a similar total dose of epidural infusion. Patient satisfaction was similarly high in both groups, and both administration routes were well tolerated.

CONCLUSIONS

The data support the superiority of epidural oxycodone compared with that of i.v. administration in pain management after laparotomy.

Oxycodone pharmacokinetics and fetal exposure after intravenous or epidural administration to the ewe

INTRODUCTION

There are limited data on oxycodone pharmacokinetics during pregnancy and on fetal exposure after maternal administration. The present study describes the pharmacokinetics of intravenous (i.v.) oxycodone in pregnant sheep and fetal exposure after intravenous and epidural administration.

MATERIAL AND METHODS

Ten pregnant sheep received 0.1 mg·kg^-1 oxycodone intravenously, and blood samples were collected up to 24 hours. Seven days later, the ewes were randomized to receive 0.5 mg·kg^-1 oxycodone intravenously (n = 5) or epidurally (n = 5) as a single bolus, before laparotomy for placement of catheters into the fetal superior vena cava and carotid artery. Paired maternal and fetal blood samples were taken when the fetal arterial catheter was in place and at the end of surgery. Maternal blood samples were taken up to 24 hours.

RESULTS

After 0.1 mg·kg^-1 oxycodone intravenously, the median clearance was 5.2 L·h^-1 ·kg^-1 (range 4.6-6.2), but the volume of distribution varied between 1.5 and 4.7 L·kg^-1 . The area under the curve was 17 h·ng·mL^-1 (range 14-19) and the plasma concentration at 2 minutes 60 ng·mL^-1 (range 50-74). Following administration of 0.5 mg·kg^-1 intravenously or epidurally, oxycodone concentrations were similar in the maternal and the fetal plasma. Accumulation of oxymorphone in the fetus occurred; fetal-to-maternal ratios were 1.3-3.5 (median 2.1) in the i.v.-group and 0.9-3.0 (1.3) in the Epidural-group.

CONCLUSIONS

We determined the pharmacokinetics of oxycodone in pregnant sheep. We showed accumulation of oxymorphone, which an active metabolite of oxycodone, in the fetus. Further studies in human pregnancies are required to evaluate the safety of oxycodone.

A prospective, randomized, open label, controlled study investigating the efficiency and safety of 3 different methods of rectus sheath block analgesia following midline laparotomy

BACKGROUND

There is a controversy regarding the efficacy of rectus sheath block (RSB). The aim of the present study was to evaluate analgesic efficacy and safety of three different methods of RSB in postoperative pain management after midline laparotomy.

METHODS

A prospective, randomized, controlled, open-label clinical trial with 4 parallel groups was conducted in a tertiary care hospital in Finland. A total of 57 patients undergoing midline laparotomy were randomized to the control group (n = 12) or to 1 of the 3 active RSB analgesia groups: single-dose (n = 16), repeated-doses (n = 12), or continuous infusion (n = 17). Opioid consumption with iv-patient-controlled analgesia pump was recorded, and pain scores and patients' satisfaction were surveyed on an 11-point numeric rating scale for the first 48 postoperative h. Plasma concentrations of oxycodone and levobupivacaine were analyzed. All adverse events during the hospital stay were recorded.

RESULTS

Oxycodone consumption was less during the first 12 h in the repeated-doses and in the continuous infusion groups (P = .07) and in numerical values up to 48 h in the repeated-doses group. Plasma oxycodone concentrations were similar in all 4 groups. Pain scores were lower in the repeated-doses group when coughing during the first 4 h (P = .048 vs. control group), and at rest on the first postoperative morning (P = .034 vs. the other 3 groups) and at 24 h (P = .006 vs. the single-dose group). All plasma concentrations of levobupivacaine were safe. The patients' satisfaction was better in the repeated-doses group compared with the control group (P = .025). No serious or unexpected adverse events were reported.

CONCLUSIONS

RSB analgesia with repeated-doses seems to have opioid sparing efficacy, and it may enhance pain relief and patients' satisfaction after midline laparotomy.

The Opioid-Sparing Effect of Perioperative Dexmedetomidine Combined with Oxycodone Infusion during Open Hepatectomy: A Randomized Controlled Trial

Background: A large right subcostal incision performed by open hepatectomy is associated with significant post-operative pain and distress. However, post-operative analgesia solutions still need to be devised. We investigated the effects of intra- and post-operative infusion of dexmedetomidine (Dex) combined with oxycodone during open hepatectomy.

Methods: In this prospective, randomized and double-blind investigation, 52 patients undergoing selective open hepatectomy were divided into Dex group (DEX infusion at an initial loading dose of 0.5 μg⋅kg^-1 over 10 min before intubation then adjusted to a maintenance dose of 0.3 μg⋅kg^-1⋅h^-1 until incision suturing) or control (Con) group (0.9% sodium chloride was administered). Patient-controlled analgesia was administered for 48 h after surgery (Dex group: 60 mg oxycodone and 360 μg DEX diluted to 120 ml and administered at a bolus dose of 2 ml, with 5 min lockout interval and a 1 h limit of 20 ml. Con group: 60 mg oxycodone alone with the same regimen). The primary outcome was post-operative oxycodone consumption. The secondary outcomes included requirement of narcotic and vasoactive drugs, hemodynamics, incidence of adverse effects, satisfaction, first exhaust time, pain intensity, and the Ramsay Sedation Scale.

Results: Post-operative oxycodone consumption was significantly reduced in Dex group from 4 to 48 h after surgery (P < 0.05). Heart rate in Dex group was statistically decreased from T1 (just before intubation) to T6 (20 min after arriving at the post-anesthesia care unit), while mean arterial pressure was significantly decreased from T1 to T3 (during surgical incision; P < 0.05). The consumption of propofol and remifentanil were significantly decreased in Dex group (P < 0.05). The VAS scores at rest at 1, 4, and 8 h and with cough at 24, and 48 h after surgery were lower, the first exhaust time were shorter, satisfaction with pain control was statistically higher and the incidence of nausea and vomiting was less in Dex group than in Con group (all P < 0.05).

Conclusion: The combination of DEX and oxycodone could reduce oxycodone consumption and the incidence of nausea and vomiting, enhance the analgesic effect, improves patient satisfaction and shorten the first exhaust time.

Effect of oxycodone patient-controlled intravenous analgesia after cesarean section: a randomized controlled study

Background

Oxycodone is a semisynthetic μ-opioid receptor agonist with a potentially good analgesic efficacy in visceral pain. This study aims to compare the efficacy of oxycodone with sufentanil patient-controlled intravenous analgesia (PCIA).

Methods

One hundred and twenty primiparas undergoing elective cesarean section were randomized into four groups by different drugs of PCIA: group S (sufentanil 100 μg), group OS1 (sufentanil 70 μg, oxycodone 30 mg), group OS2 (sufentanil 50 μg, oxycodone 50 mg), and group O (oxycodone 100 mg). Ramosetron 0.3 mg was added to each group. In all groups, drugs were diluted to 100 mL and managed with a continuous infusion of 1 mL·h⁻¹, a bolus dose of 2 mL, and a lockout interval of 15 min. The maximum dose of PCIA per hour was 10 mL. After surgery, pain scores, PCIA doses, and side effects were compared among groups.

Results

At all time points (6, 12, and 24 h after surgery), Numerical Rating Scale (NRS) of uterine cramping pain (NRS-U) scores in group O were lower than those in groups OS1 and S (P<0.008) and NRS-U scores in groups OS2 and OS1 were lower than that in group S (P<0.008). NRS of moving into the sitting position (NRS-S) scores in group O were lower than those in the other groups (P<0.008). NRS-S scores in group OS2 were lower than those in groups OS1 and S (P<0.008). At 12 and 24 h after surgery, NRS of incision pain at rest (NRS-R) scores in group O were lower than those in the other groups (P<0.008). At all time points, NRS-R scores in group OS2 were lower than those in groups OS1 and S (P<0.008). The number of PCIA boluses and amount of opioid consumption in group O were lower than those in groups OS1 and S at all time points (P<0.008).

Conclusion

Oxycodone PCIA may be more effective than sufentanil PCIA for pain relief after cesarean section but the incidence of side effects needs further investigation.

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.

Effect of Preoperative Intravenous Oxycodone After Transurethral Resection of Prostate Under General Anesthesia

The objective of this study was to investigate the effect of intravenous oxycodone administered before transurethral resection of prostate (TURP) on postoperative pain and tramadol consumption. Preemptive analgesia can decrease postoperative pain and analgesic consumption. Sixty patients undergoing elective TURP were divided into 2 groups: group O (n = 30) received intravenous oxycodone (0.1 mg/kg) 10 minutes before surgery over 2 minutes and group C (n = 30) received normal saline as a placebo. A standardized general anesthesia method was performed with a laryngeal mask airway device. Data with respect to pain intensity, incidence of lower urinary tract discomfort, time to the first tramadol requirement, tramadol consumption, overall patient satisfaction, and adverse effects were collected. Preoperative oxycodone contributed to better analgesia at 1, 2, 6, and 12 hours after shifting the patients to the recovery room, a longer time interval to the first tramadol request, fewer patients requiring tramadol analgesia, and reduced tramadol consumption. Adverse effects were comparable between the 2 groups. Preoperative intravenous oxycodone (0.1 mg/kg) 10 minutes before TURP improves postoperative analgesia, prolongs time to the first tramadol request, and reduces tramadol consumption without an influence on lower urinary tract discomfort and adverse effects.

Analgesic efficacy, adverse effects, and safety of oxycodone administered as continuous intravenous infusion in patients after total hip arthroplasty

Background

Total hip arthroplasty (THA) causes extensive tissue damage and severe pain. This study aimed to assess the analgesic efficacy, adverse effects (AEs), and safety of continuous intravenous (iv) oxycodone infusion with ketoprofen (injected into the iv line) in patients after THA, and to assay serum oxycodone levels.

Patients and methods

Fourteen patients, aged 59‒82 years with American Society of Anesthesiologists (ASA) classification I or III, underwent THA with intrathecal analgesia and sedation induced by iv propofol. After the surgery, oxycodone (continuous iv infusion) at a dose of 1 mg/h (five patients) or 2 mg/h (nine patients) with 100 mg ketoprofen (injected into the iv line) was administered to each patient every 12 h. Pain was assessed using a numerical rating scale (NRS: 0 – no pain, 10 – the most severe pain) at rest and during movement. AEs, including hemodynamic unsteadiness, nausea, vomiting, pruritus, cognitive impairment, and respiratory depression, were registered during the first 24 h after surgery.

Results

Oxycodone (continuous iv infusion) at a dose of 2 mg/h with ketoprofen (100 mg) administered every 12 h provided satisfactory analgesia in all nine patients without the need of rescue analgesics within the first 24 h after THA. In three out of five patients, oxycodone at 1 mg/h was effective. Oxycodone did not induce drowsiness, vomiting, pruritus, respiratory depression, or changes in blood pressure. Bradycardia appeared in two patients, and nausea was observed in one patient.

Conclusion

Oxycodone infusion with ketoprofen administered by iv is effective in patients after THA. Intravenous infusion of oxycodone is a predictable, stable, and safe method of drug administration.

Opioid-Induced Bowel Dysfunction in Patients Undergoing Spine Surgery: Comparison of Oxycodone and Oxycodone-Naloxone Treatment

Introduction

Opioids are needed for postoperative pain in spine surgery patients, but opioid-induced constipation is a harmful adverse event. The aim of this clinical trial was to compare the use of a controlled-release oxycodone-naloxone combination product with oxycodone controlled-release tablets in these patients. The main outcome measure was the prevalence of constipation at 7 days postoperatively assessed with a Bowel Function Index questionnaire. A follow-up assessment at 21 days after surgery was also included.

Methods

A total of 180 patients undergoing spine surgery, 91 having preoperative opioids in use and 89 opioid-naïve, were randomized to receive twice-daily oxycodone 10 mg or oxycodone-naloxone 10/5 mg controlled-release tablets for the first 7 postoperative days. Patients were followed-up for 21 days after surgery.

Results

At baseline, prevalence of constipation was common both in the opioid-naïve—25/87 (29%) and on-opioid groups 43/90 (48%) (P = 0.009). This increased at 7 days postoperatively with no difference between the groups, 54/89 with oxycodone and 54/88 with oxycodone-naloxone had constipation. At 21 days, constipation was less than in the baseline in both groups, in the opioid-naïve group the prevalence of constipation was 3/43 (7%) in patients with oxycodone-naloxone compared to 9/44 (21%) with oxycodone (effect size 0.68; P = 0.068). Both study compounds provided similar pain relief and were well tolerated.

Conclusion

In patients presented for back surgery, the prevalence of constipation was significantly higher than that in the community. In opioid-naïve subjects, oxycodone-naloxone was beneficial concerning constipation; but this was not distinguishable in subjects with chronic opioid use. The analgesic efficacy of oxycodone and oxycodone-naloxone was similar.

Trial registration: European Clinical Trials Database (EudraCT no. 2012-001816-42) and ClinicalTrials.gov database (Identifier: NCT02573922).

Maturation of oxycodone pharmacokinetics in neonates and infants: Oxycodone and its metabolites in plasma and urine

AIMS

This study aimed to characterize the pharmacokinetics of oxycodone and its major metabolites in infants and covered the age range between extremely preterm neonates and 2-year-old infants.

METHODS

Seventy-nine infants (gestational age 23-42 weeks; postnatal age 0-650 days) received intravenous oxycodone hydrochloride trihydrate at a dose of 0.1 mg kg^-1 during or after surgery. Three to seven blood samples were taken from each infant, and plasma concentrations of oxycodone, noroxycodone, oxymorphone, and noroxymorphone were quantified. The unconjugated forms of these compounds were determined in urine collected after up to 24 or 48 h from 25 infants. Pharmacokinetics was determined using noncompartmental analysis and reported for six clinically relevant age groups based on postmenstrual age.

RESULTS

Oxycodone pharmacokinetics changed markedly with patient age. Preterm neonates were found to have the highest pharmacokinetic variability out of the study population. In extremely preterm neonates (n = 6) median of elimination half-life was 8.8 h (range 6.8-12.5), in preterm (n = 11) 7.4 h (4.2-11.6), and in older neonates (n = 22) 4.1 h (2.4-5.8), all of which were significantly longer than that in infants aged 6-24 months (n = 12) 2.0 h (1.7-2.6). Median renal clearance was fairly constant in all age groups, whereas non-renal clearance markedly increased with age. Noroxycodone was the major metabolite in plasma and urine.

CONCLUSIONS

Oxycodone elimination is slower and pharmacokinetic variability more pronounced in neonates when compared to older infants. These findings highlight the importance of careful dose titration for neonates.

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.

Pharmacotherapy of Pain in the Older Population: The Place of Opioids

Pain is a common symptom in older people. It is possible that pain is underreported in older persons due to an incorrect belief that it is an inevitable part of aging. Opioid analgesics are potent medications, with confirmed efficacy for the treatment of moderate to severe pain. These drugs are commonly used in older persons. However, there is insufficient evidence regarding safety of opioids in older patients. One of the reasons for this is the lack of randomized, controlled clinical trials. People of advanced age often have comorbidites and use other prescription drugs, as well as over-the-counter (OTC) compounds, thus making them more suceptible to the risk of interactions with opioids. Significant pharmacokinetic and pharmacodynamic changes that occur with advancing age increase the risk of adverse effects of opioids. There are also some discrepancies between guidelines, which recommend the use of lower doses of opioids in older patients, and the findings in the literature which suggest that pain is often undertreated in this age group. It seems that there are significant variations in the tolerability of different opioid analgesics in older people. Morphine, fentanyl, oxycodone, and buprenorphine are still the preferred evidence-based choices for add-on opioid therapy for these patients. However, the safety and efficacy of other opioids in older patients, especially if comorbidities and polypharmacy are present, is still questionable. This review addresses the most important aspects of the use of opioids in older persons, focusing on pharmacokinetics, pharmacodynamics, adverse effects, and interactions.

Present-day challenges and future solutions in postoperative pain management: results from PainForum 2014

This paper is a summary of presentations on postoperative pain control by the authors at the 2014 PainForum meeting in People's Republic of China. Postoperative pain is often untreated or undertreated and may lead to subsequent chronic pain syndromes. As more procedures migrate to the outpatient setting, postoperative pain control will become increasingly more challenging. Evidence-based guidelines for postoperative pain control recommend pain assessment using validated tools on a consistent basis. In this regard, consistency may be more important than the specific tool selected. Many hospitals have introduced a multidisciplinary acute pain service (APS), which has been associated with improved patient satisfaction and fewer adverse events. Patient education is an important component of postoperative pain control, which may be most effective when clinicians chose a multimodal approach, such as paracetamol (acetaminophen) and opioids. Opioids are a mainstay of postoperative pain control but require careful monitoring and management of side effects, such as nausea, vomiting, dizziness, and somnolence. Opioids may be administered using patient-controlled analgesia systems. Protocols for postoperative pain control can be very helpful to establish benchmarks for pain management and assure that clinicians adhere to evidence-based standards. The future of postoperative pain control around the world will likely involve more and better established APSs and greater communication between patients and clinicians about postoperative pain. The changes necessary to implement and move forward with APSs is not a single step but rather one of continuous improvement and ongoing change.

Preoperative versus postoperative ultrasound-guided rectus sheath block for improving pain, sleep quality and cytokine levels of patients with open midline incisions undergoing transabdominal gynaecological operation: study protocol for a randomised controlled trial

Background

Rectus sheath block (RSB) is used for postoperative pain relief in patients undergoing abdominal surgery with midline incision. Preoperative RSB has been shown to be effective, but it has not been compared with postoperative RSB. The aim of the present study is to evaluate postoperative pain, sleep quality and changes in the cytokine levels of patients undergoing gynaecological surgery with RSB performed preoperatively versus postoperatively.

Methods/Design

This study is a prospective, randomised, controlled (randomised, parallel group, concealed allocation), single-blinded trial. All patients undergoing transabdominal gynaecological surgery will be randomised 1:1 to the treatment intervention with general anaesthesia as an adjunct to preoperative or postoperative RSB. The objective of the trial is to evaluate postoperative pain, sleep quality and changes in the cytokine levels of patients undergoing gynaecological surgery with RSB performed preoperatively (n = 32) versus postoperatively (n = 32). All of the patients, irrespective of group allocation, will receive patient-controlled intravenous analgesia (PCIA) with oxycodone.

The primary objective is to compare the interval between leaving the post-anaesthesia care unit and receiving the first PCIA bolus injection on the first postoperative night between patients who receive preoperative versus postoperative RSB. The secondary objectives will be to compare (1) cumulative oxycodone consumption at 24 hours after surgery; (2) postoperative sleep quality, as measured using a BIS-Vista monitor during the first night after surgery; and (3) cytokine levels (interleukin-1, interleukin-6, tumour necrosis factor-α and interferon-γ) during surgery and at 24 and 48 hours postoperatively.

Discussion

Clinical experience has suggested that RSB is a very effective postoperative analgesic technique, and we will answer the following questions with this trial. Do preoperative block and postoperative block have the same duration of analgesic effects? Can postoperative block extend the analgesic time? The results of this study could have actual clinical applications that could help to reduce postoperative pain and shorten hospital stays.

Trial registration

Current Controlled Trials NCT02477098 15 June 2015.

Comparison of oxycodone and fentanyl for postoperative patient-controlled analgesia after laparoscopic gynecological surgery

BACKGROUND

Opioids are widely used in boluses and patient-controlled analgesia (PCA) for postoperative pain control. In this study, we compared the effects of oxycodone and fentanyl on postoperative pain in patients with intravenous patient-controlled analgesia (IV-PCA) after laparoscopic gynecological surgery.

METHODS

Seventy-four patients undergoing elective total laparoscopic hysterectomy or laparoscopic myomectomy were randomly assigned to the administration of either fentanyl or oxycodone using IV-PCA (potency ratio 1 : 60). The cumulative dose administered in the patient-controlled mode during the initial 48 hours after the operation was measured. Patients were also assessed for postoperative pain severity, adverse effects, and patient satisfaction.

RESULTS

No significant differences were observed in patient satisfaction with the analgesia during the postoperative period. Patients in the oxycodone group experienced significantly more dizziness compared to the fentanyl group. Patients in the oxycodone group showed significantly lower consumption of opioid in the patient-controlled mode (10.1 ± 8.5 ml vs. 16.6 ± 12.0 ml, P = 0.013).

CONCLUSIONS

Our data suggest that oxycodone and fentanyl demonstrated similar effects, and therefore oxycodone may be a good alternative to fentanyl in postoperative pain management. Further studies in various clinical settings will be needed to determine the adequate potency ratio.

Safety and tolerability of controlled-release oxycodone on postoperative pain in patients submitted to the oncologic head and neck surgery

OBJECTIVE

To evaluate the safety and tolerability of controlled-release oxycodone in the treatment of postoperative pain of head and neck oncologic resections.

METHODS

We conducted a prospective, observational and open study, with 83 patients with moderate to severe pain after head and neck oncological operations. All patients received general anesthesia with propofol, fentanyl and sevoflurane. Postoperatively, should they have moderate or severe pain, we began controlled-release oxycodone 20 mg 12/12 b.i.d on the first day and 10 mg b.i.d. on the second. We assessed the frequency and intensity of adverse effects, the intensity of postoperative pain by a verbal numeric scale and the use of rescue analgesia from 12 hours after administration of the drug and between 7 and 13 days after the last oxycodone dose.

RESULTS

The most common adverse events were nausea, vomiting, dizziness, pruritus, insomnia, constipation and urinary retention, most mild. No serious adverse events occurred. In less than 12 hours after the use of oxycodone, there was a significant decrease in the intensity of postoperative pain, which remained until the end of the study. The rescue medication was requested at a higher frequency when the opioid dose was reduced, or after its suspension.

CONCLUSION

Controlled release oxycodone showed to be safe and well tolerated and caused a significant decrease in post-operative pain.

OPRM1 A118G Gene Variant and Postoperative Opioid Requirement

Background:

Although a number of studies have investigated the association of the OPRM1 A118G polymorphism with pain response, a consensus has not yet been reached.

Methods:

The authors searched PubMed, EMBASE, and the Cochrane Library to identify gene-association studies that explored the impact of the OPRM1 A118G polymorphism on postoperative opioid requirements through July 2013. Two evaluators independently reviewed and selected articles on the basis of prespecified selection criteria. The authors primarily investigated the standardized mean difference (SMD) of required amounts of opioids between AA homozygotes and G-allele carriers. The authors also performed subgroup analyses for race, opioid use, and type of surgery. Potential bias was assessed using the Egger’s test with a trim and fill procedure.

Results:

Three hundred forty-six articles were retrieved from databases, and 18 studies involving 4,607 participants were included in the final analyses. In a random-effect meta-analysis, G-allele carriers required a higher mean opioid dose than AA homozygotes (SMD, −0.18; P = 0.003). Although there was no evidence of publication bias, heterogeneity was present among studies (I2 = 66.8%). In the subgroup meta-analyses, significance remained robust in Asian patients (SMD, −0.21; P = 0.001), morphine users (SMD, −0.29; P &lt;0.001), and patients who received surgery for a viscus (SMD, −0.20; P = 0.008).

Conclusions:

The OPRM1 A118G polymorphism was associated with interindividual variability in postoperative response to opioids. In a subpopulation, identifying OPRM1 A118G polymorphism may provide valuable information regarding the individual analgesic doses that are required to achieve satisfactory pain control.

Oxycodone vs. fentanyl patient-controlled analgesia after laparoscopic cholecystectomy

OBJECTIVES

Oxycodone is semi-synthetic opioid, oral and parenteral preparations have been widely used for acute and chronic pain. The aim of this study was to assess the efficacy and side effects of oxycodone and fentanyl in patient controlled analgesia (PCA) after laparoscopic cholecystectomy.

METHODS

A prospective, randomized, double-blind study was conducted. 81 patients were randomly divided into two groups; fentanyl (10 mcg fentanyl and 1.5 mg ketorolac) and oxycodone group (1 mg oxycodone and 1.5 mg ketorolac). After the operation, a blinded observer assessed pain using a numerical rating scale (NRS), infused PCA dose, side effects, sedation levels, and satisfaction.

RESULTS

Cumulative PCA dose of oxycodone group at 48 h (31.4 ± 16.0 ml) was significantly less than that of fentanyl group (43.8 ± 23.1 ml, P = 0.009). Oxycodone group showed more nausea at 6-24 h after the operation (P = 0.001), but there was no difference in satisfaction score (P = 0.073). There were no significant differences in other side effects, sedation and NRS scores between two groups.

CONCLUSION

Oxycodone showed comparable effects for pain relief compared to fentanyl in spite of less cumulative PCA dose. Based on these results, we could conclude that oxycodone may be useful as an alternative to fentanyl for PCA after laparoscopic cholecystectomy.

Prolonged-release Oxycodone/Naloxone in Postoperative Pain Management: From a Randomized Clinical Trial to Usual Clinical Practice

Objective:

These studies evaluated the feasibility of using oral prolonged-release oxycodone/naloxone (OXN PR) for the management of acute postoperative pain.

Methods:

Three studies were undertaken: (i) the analgesic efficacy of OXN PR was compared with prolonged-release oxycodone (OXY PR) in patients with knee arthroplasty in an immediate postoperative period (IPOP) study; (ii) OXN PR treatment was compared with other opioids during rehabilitation after knee arthroplasty in a noninterventional study (NIS); and (iii) surgical patients on other opioids were switched to OXN PR postoperatively during a quality improvement programme (QIP).

Results:

In the IPOP study, the pain intensity at rest score decreased by a similar amount in the OXN PR and OXY PR groups, indicating similar analgesic efficacies. In the NIS, patient assessments indicated enhanced efficacy and tolerability for OXN PR compared with other opioids. The QIP indicated significant improvements in bowel function and less difficulty passing urine at the end of OXN PR treatment compared with baseline. No safety concerns were raised.

Conclusions:

The analgesic efficacies of OXN PR and OXY PR were similar in postoperative pain settings. OXN PR reduced the degree of restriction in relation to patients carrying out physio - therapy compared with other opioids, and improved bowel and bladder function.