Comparison of Propofol and Fentanyl for Preventing Emergence Agitation Following Sevoflurane Anesthesia in Pediatric Patients: A Single-Center Study in Bangladesh

Background: Emergence agitation (EA) is a common phenomenon observed in pediatric patients following general anesthesia. This study aimed to assess the efficacy of propofol and fentanyl in preventing EA and to compare their associated complications or side effects. Methods: This prospective randomized observational comparative study was conducted at Dhaka Medical College Hospital from July 2013 to June 2014. The study aimed to evaluate the effects of propofol and fentanyl on EA in children aged 18 to 72 months undergoing circumcision, herniotomy, and polypectomy operations. Ninety children were included in the study, with 45 in each group. Patients with psychological or neurological disorders were excluded. Various parameters including age, sex, weight, American Society of Anesthesiologists (ASA) class, duration of anesthesia, Saturation of Peripheral Oxygen (SPO2), heart rate (HR), respiratory rate (RR), Pediatric Anesthesia Emergence Delirium (PAED) score, duration of post-anesthesia care unit (PACU) stay, incidence of laryngospasm, nausea, vomiting, and rescue drug requirement were compared between the two groups. Results: Age, sex, weight, ASA class, and duration of anesthesia were comparable between the two groups. Perioperative SpO2 and HR were similar in both groups. However, the PAED score was significantly higher in the fentanyl group during all follow-ups except at 30 minutes postoperatively. The mean duration of PACU stay was significantly longer in the fentanyl group. Although the incidence of laryngospasm was higher in the fentanyl group, it was not statistically significant. Conversely, nausea or vomiting was significantly higher in the fentanyl group. The requirement for rescue drugs was significantly higher in the fentanyl group compared to the propofol group. Conclusion: Both propofol and fentanyl were effective in preventing emergence agitation in pediatric patients undergoing various surgical procedures under sevoflurane anesthesia. However, propofol demonstrated a better safety profile with fewer incidences of nausea, vomiting, and rescue drug requirements compared to fentanyl.

Fentanyl and xylazine crisis:Crafting coherent strategies for opioid overdose prevention

The United States is in the throes of a severe opioid overdose epidemic,primarily fueled by the pervasive use of fentanyl and the emerging threat of xylazine,a veterinary sedative often mixed with fentanyl.The high potency and long duration of fentanyl is compounded by the added risks from xylazine,heightening the lethal danger faced by opioid users.Measures such as enhanced surveillance,public awareness campaigns,and the distribution of fentanylxylazine test kits,and naloxone have been undertaken to mitigate this crisis.Fentanyl-related overdose deaths persist despite these efforts,partly due to inconsistent policies across states and resistance towards adopting harm reduction strategies.A multifaceted approach is imperative in effectively combating the opioid overdose epidemic.This approach should include expansion of treatment access,broadening the availability of medications for opioid use disorder,implementation of harm reduction strategies,and enaction of legislative reforms and diminishing stigma associated with opioid use disorder.

Neonatal Cord Tox Panel and Maternal Perinatal Fentanyl Exposure: A Retrospective Chart Review

Objective: The specific aim of this study was to determine if the currently available cutoff for fentanyl in umbilical cord (UC) was appropriate to distinguish illicit fentanyl exposure from therapeutic in-hospital administration of fentanyl. Study Design: Medical record review was conducted for perinatal administration of fentanyl and the detection of fentanyl in the corresponding routine UC toxicology. Specimens were initially tested with immunoassay followed by mass spectrometry (n = 62). Result: Excluding a single specimen that was confirmed positive, specimens were below the assays’ limit of quantification. The immunoassay’s mean b/b0 for the cases that received and did not receive fentanyl prior to delivery was 91.3% ± 10.6% and 98.2% ± 6.5%, respectively (p = 0.003). Conclusion: We demonstrated that UC is a suitable specimen type for the detection of fentanyl and that the cutoff selected adequately identifies illicit fentanyl use while not flagging cases where fentanyl was administered by the hospital prior to birth.

Evaluation of the clinical effects of atropine in combination with remifentanil in children undergoing surgery for acute appendicitis

BACKGROUND Acute appendicitis(AA)is the most common cause of acute abdomen in children.Anesthesia significantly influences the surgical treatment of AA in children,making the scientific and effective selection of anesthetics crucial.AIM To assess the clinical effect of atropine(ATR)in combination with remifentanil(REMI)in children undergoing surgery for AA.METHODS In total,108 cases of pediatric AA treated between May 2020 and May 2023 were selected,58 of which received ATR+REMI[research group(RG)]and 50 who received REMI[control group(CG)].Comparative analyses were conducted on the time to loss of eyelash reflex,pain resolution time,recovery time from anesthesia,incidence of adverse events(AEs;respiratory depression,hypoxemia,bradycardia,nausea and vomiting,and hypotension),intraoperative responses(head shaking,limb activity,orientation recovery,safe departure time from the operating room),hemodynamic parameters[oxygen saturation(SPO2),mean arterial pressure,heart rate,and respiratory rate],postoperative sedation score(Ramsay score),and pain level[the Face,Legs,Activity,Cry,Consolability(FLACC)Behavioral Scale].RESULTS Compared with the CG,the RG showed significantly shorter time to loss of eyelash reflex,pain resolution,recovery from anesthesia,and safe departure from the operating room.Furthermore,the incidence rates of overall AEs(head shaking,limb activity,etc.)were lower,and influences on intraoperative hemodynamic parameters and stress response indexes were fewer.The Ramsay score at 30 min after extubation and the FLACC score at 60 min after extubation were significantly lower in the RG than in the CG.CONCLUSION ATR+REMI is superior to REMI alone in children undergoing AA surgery,with a lower incidence of AEs,fewer influences on hemodynamics and stress responses,and better post-anesthesia recovery.

Transdermal Fentanyl for Management of Cancer Pain in Elderly Patients in China

Objective: Objective: To assess the effect and adverse effects of transdermal fentanyl for elderly patients with cancer pain in China. Methods: A total of 1664 elderly patients (aged 65-90 with mean age of 72.6) with cancer pain enrolled in the multicenter study from 136 institutes in China. Of them, 408 (28.8%) patients were 75 years old or older. All patients received transdermal fentanyl for the management of cancer pain. The patients were asked to record the attacks of pain, quality of life, and any side effects of the treatment. Results: Baseline mean of pain intensity was 7.34. On day 1, 3, 6, 9 15, and 30, the pain mean scores were decreased to 3.82, 2.80, 2.43, 2.11, 1.83, 1.64 (P=0.000). The effective rate was 97.18%. The mean doses of fentanyl was 31.34 g/h (25-150 g/h) initially, and 40.59 g/h and 47.50 g/h (25-200 g/h) at day 15 and day 30. At treatment day 15, the dose of fentanyl was ranger from 25 to 50 g/h in 91.8% of patients, 75 to 100 g/h in 7.5% patients, and 125 to 200 g/h only in 0.8% patients. The fine quality of life was in 25.4% patients before treatment, and was 71.15% and 73.04% at day 15 and day 30 respectively (P=0.0000). The common side effects were constipation (10.70%), nausea (11.96%), dizzy (6.85%), vomiting (3.85%), sedation (2.40%), Respiratory depression (0.12%). 86.2% patients preferred continue treated by transdermal fentanyl. Conclusions: Transdermal fentanyl for the elderly with cancer pain is effective, safe, convenient, and can improve the quality of life. Transdermal fentanyl can be recommended as a first-line drug for the treatment of elderly patients with moderate to severe cancer pain, and the initial doses is recommended as 25 g/h.

The Effect of Test Dose Fentanyl on Predicting Postoperative Respiratory Depression in Patients with Continuous Intravenous Morphine Analgesia

Objective: To evaluate the effect of test dose fentanyl on predictingpostoperative analgesia and respiratory depression. Methods: Preoperatively the lowest pulseoximeter saturation (SpO_2) under room air breathing was measured after 2 μg/kg of fentanyl givenintravenously in 35 patients who were scheduled with continuous intravenous morphine analgesia (12μg·kg^(-1)·h^(-1)) postoperatively. Results: The test dose fentanyl resulted in respiratorydepression in 19 of 35 cases, while 8 (42.1%) of the 19 cases developed respiratory depressionpostoperatively. However in the rest 16 patients, no patient (0) developed respiratory depression (P< 0.01). The fentanyl-induced lowest SpO_2 significantly correlated with the lowest SpO_2postoperatively (P < 0.01). The analgesia effect in terms of verbal analogue scale was correlatedneither with the fentanyl-induced lowest SpO_2 nor with the lowest SpO_2 postoperatively (P > 0.05).Conclusion: The patient who was sensitive to fentanyl-induced respiratory depression would take ahigh risk to develop postoperative respiratory depression with intravenous morphine analgesia andthe patient with respiratory depression does not always go with satisfactory analgesia.

4-取代Fentanyl类化合物电子结构及构效关系研究

本文对十一个4-取代Fentanyl类化合物进行了量子化学(INDO)计算,研究了它们的电子结构及构效关系.结果表明,这些化合物同其他Fentanyl类化合物在主要活性部位和电子结构趋势上基本相同.酰胺氧原子是最重要的负电中心,哌啶氮原子在季铵化后发挥正电中心作用.4-取代基的极性基团可能以电荷转移作用或氢键接受体形式与受体极性部位结合,并能影响其他活性部位电子密度,另外,4-取代基的立体因素与疏水因素同生物活性相关.

Using Umbilical Cord Tissue to Identify Prenatal Exposure to Fentanyl and Other Commonly Abused Drugs

Background: Prenatal exposure to fentanyl may lead to Neonatal Abstinence Syndrome (NAS), a constellation of symptoms observed when newborns begin withdrawing from addictive substances such as opioids. The use of umbilical cord tissue segments (UC) for newborn toxicology has been increasing due to its apparent long detection window, sensitivity, and ease of collection. However, very little has been reported in the literature concerning the prevalence of in utero exposure to fentanyl and co-exposure with other commonly abused substances. Specific aim: The specific aims of this retrospective study are twofold. We will report prevalence of neonatal exposure to fentanyl for a nationwide high-risk population using UC submitted to a national reference laboratory for routine forensic toxicology analysis and the co-exposure patterns observed for these fentanyl-exposed neonates. Methods: A secondary analysis was performed using historical data for UC received between January 1, 2020 and December 31, 2020 for routine forensic toxicology analysis. Results: During the study period, our laboratory received 23,104 UC for analysis and 9667 (41.8%) of those UC were positive for at least one drug. The prevalence of fentanyl detection was 1.9% (n = 429). Of these 429 specimens there were 407 UC where both fentanyl and norfentanyl were detected. There were 14 UC where only fentanyl was detected and 8 UC where only norfentanyl was detected. When detected, the median concentrations of fentanyl and norfentanyl were 4029 pg/g (IQR: 1696, 9230 pg/g) and 10,756 pg/mg (IQR: 3925, 25,288 pg/g), respectively. Of the 429 positive fentanyl and/or norfentanyl UC, 33 (7.7%) were only positive for fentanyl and/or norfentanyl. Of the 396 polypositive UC, morphine was the highest co-exposure with 243 UC (56.6%) being positive for both fentanyls and morphine. The second most prevalent co-exposure observed was methamphetamine/amphetamine (n = 173;40.3%) followed by cannabinoids (n = 113;26.3%) and benzoylecgonine (cocaine metabolite;n = 106;24.7%). Conclusions: Nonmedical use of fentanyl is an alarming trend in this country including this maternal demographic reported here. Fentanyl was typically found with other commonly abused substances.

Comparison of bolus remifentanil versus bolus fentanyl for blunting cardiovascular intubation responses in children： a randomized, double-blind study

Background The authors found no study to compare the efficacy of bolus dose fentanyl and remifentanil blunting the cardiovascular intubation response in children, so they designed this randomized, double-blind clinical study to assess the effects of remifentanil 2 μg/kg and fentanyl 2 μg/kg by bolus injection on the cardiovascular intubation response in healthy children.Methods One hundred and two children, the American Society of Anesthesiologists （ASA） physical status 1-2 and scheduled for elective plastic surgery under general anesthesia, were randomly divided into one of two groups to receive the following treatments in a double blind manner： remifentanil 2μg/kg （Group R） and fentanyl 2 μg/kg （Group F） when anesthesia was induced with propofol and vecuronium. The orotracheal intubation was performed using a direct laryngoscope. Blood pressure （BP） and heart rate （HR） were recorded before anesthesia induction （baseline values）, immediately before intubation, at intubation and every minute for 5 minutes after intubation. The percent changes of systolic blood pressure （SBP） and HR relative to baseline values and the rate pressure product （RPP） at every observing point were calculated. The incidences of SBP and HR percent changes 〉30% of baseline values and RPP 〉22 000 during the observation were recorded.Results There were no significant differences between groups in the demographic data, baseline values of BP and HR and the intubation time. As compared to baseline values, BP, HR and RPP at intubation and their maximum values during observation increased significantly in Group F, but they all decreased significantly in Group R. BP, HR and RPP at all observed points, and their maximum values during the observation, were significantly different between groups. There were also significant differences between groups in the percent change of SBP and HR relative to baseline values at all observed points and their maximum percent changes during the observation. The incidences of SBP and HR percent increased 〉30% of the baseline values and RPP 〉22 000 during the observation, were significantly higher in Group F than in Group R, but the incidences of SBP and HR percent decreased 〉30% of baseline values were significantly lower in Group F compared with Group R.Conclusions When used as part of routine anesthesia induction with propofol and vecuronium in children, fentanyl 2 μg/kg by bolus injection fails to effectively depress the cardiovascular intubation response. Remifentanil 2 μg/kg by bolus injection can completely abolish the cardiovascular intubation response, but also cause more adverse complications of temporary siclnificant cardiovascular depression.

Pharmacokinetics of Remifentanil in Chinese Patients Undergoing Elective Surgery

Aim To study the pharmacokinetics of remifentanil in Chinese aduh patients undergoing elective surgery and compare the results with the data already published. Methods The pharmacokinetics of remifentanil was determined in 10 aduh patients undergoing elective surgery. Remifentanil 5 - 6 μg·kg^-1 was administered within 1 min after the induction of anesthesia. One point five millilitre of arterial blood samples were collected at 0 （baseline）, 1,2, 3, 5,7, 10, 15, 20, 25, 30, 45, 60, and 90 min after drug administration. Remifentanil concentration was assayed by HPLC/MS/MS. Resuits The concentration-time course of remifentanil was best described by a two-compartment model. Total clearance （CL = 2. 149 ± 0. 431 L·min^-1） of remifentanil was greater than the normal hepatic blood flow. The distribution half-life （t1/2α） [ 1.56 ± 0. 52 min （0.73 - 2.31 ） ] and the elimination half-life （t1/2β） [22.07 ± 10.30 min （9, 71 -36.07）] were similar with those in previous reports. Volume of distribution （ Vd = 65. 766 ± 29. 100 L） was about two times greater than that reported in previous studies of other ethnics. Conclusion In the present study, the volume of distribution is significantly greater than thai reported in previous studies of other ethnics, indicating that there are some differences in the pharmacokinetics of remifentanil among different ethnics.

Effects of Morphine,Fentanyl and Tramadol on Human Immune Response

Summary： Morphine has been reported to suppress human immune response. We aimed to observe the effects of morphine, fentanyl and tramadol on NF- K B and IL-2 from both laboratory and clinical perspective. Jurkat cells were incubated with ten times clinically relevant concentrations of morphine, fentanyl and tramadol before being stimulated with PMA. NF- κB binding activity and IL-2 levels were measured, In the clinical study, 150 consenting patients were randomized into 3 groups according to the analgesics used in them, namely, group morphine （M）, group fentanyl （F） and group tramadol （T）. IL-2 was measured preoperatively and 1, 3 and 24 h after operation. Consequently, NF-κB activation was suppressed by morphine and fentanyl but not by tramadol. IL-2 was significantly decreased by morphine and fentanyl but not by tramadol in vitro. In the PCA patients, IL-2 was decreased in group M and increased in group F postoperatively. Whereas in group T, IL-2 was unchanged 1 h after operation but was significantly elevated 3 and 24 h after operation. Our results showed that the inhibition of morphine on IL-2 was most probably related to its suppression on NF-κB, Fentanyl had different effects on human immune response in vitro and in vivo. Tramadol may have immune enhancing effect.

Multicenter Clinical Study for Evaluation of Efficacy and Safety of Transdermal Fentanyl Matrix Patch in Treatment of Moderate to Severe Cancer Pain in 474 Chinese Cancer Patients

Objective: Although a new matrix formulation fentanyl has been used throughout the world for cancer pain management, few data about its efficacy and clinical outcomes associated with its use in Chinese patients have been obtained. This study aimed to assess the efficacy and safety of the new system in Chinese patients with moderate to severe cancer pain. Methods: A total of 474 patients with moderate to severe cancer pain were enrolled in this study and were treated with the new transdermal fentanyl matrix patch (TDF) up to 2 weeks. All the patients were asked to record pain intensity, side effects, quality of life (QOL), adherence and global satisfaction. The initial dose of fentanyl was 25 ?g/h titrated with opioid or according to National Comprehensive Cancer Network (NCCN) guidelines. Transdermal fentanyl was changed every three days. Results: After 2 weeks. The mean pain intensity of the 459 evaluated patients decreased significantly from 5.63?1.26 to 2.03?1.46 (P<0.0001). The total remission rate was 91.29%, of which moderate remission rate 53.16%, obvious remission rate 25.49% and complete remission rate 12.64%. The rate of adverse events was 33.75%, 18.78% of which were moderate and 3.80% were severe. The most frequent adverse events were constipation and nausea. No fatal events were observed. The quality of life was remarkably improved after the treatment (P<0.0001). Conclusion: The new TDF is effective and safe in treating patients with moderate to severe cancer pain, and can significantly improve the quality of life.

Determination of structure-activity relationships between fentanyl analogs and human μ-opioid receptors based on active binding site models

Fentanyl is a potent and widely used clinical narcotic analgesic, as well as a highly selective IJ-opioid agonist. The present study established a homologous model of the human μ-opioid receptor; an intercomparison of three types of μ-opioid receptor protein sequence homologous rates was made. The secondary receptor structure was predicted, the model reliability was assessed and verified using the Ramachandran plot and ProTab analysis. The predictive ability of the CoMFA model was further validated using an external test set. Using the Surflex-Dock program, a series of fentanyl analog molecules were docked to the receptor, the calculation results from Biopolymer/SitelD showed that the receptor had a deep binding area situated in the extracellular side of the transmembrane domains （TM） among TM3, TM5, TM6, and TMT. Results suggested that there might be 5 active areas in the receptor. The important residues were Asp147, Tyr148, and Tyr149 in TM3, Trp293, and His297 in TM6, and Trp318, His319, Ile322, and Tyr326 in TM7, which were located at the 5 active areas. The best fentanyl docking orientation position was the piperidine ring, which was nearly perpendicular to the membrane surface in the 7 TM domains. Molecular dynamic simulations were applied to evaluate potential relationships between ligand conformation and fentanyl substitution.

Fentanyl inhibits glucose-stimulated insulin release from β-cells in rat pancreatic islets

AIM： TO explore the effects of fentanyl on insulin release from freshly isolated rat pancreatic islets in static culture. METHODS： Islets were isolated from the pancreas of mature Sprague Dawley rats by common bile duct intraductal collagenase V digestion and were purified by discontinuous Ficoll density gradient centrifugation. The islets were divided into four groups according to the fentanyl concentration： control group （0 ng/mL）, group I （0.3 ng/mL）, group I （3.0 ng/mL）, and group III （30 ng/mL）. In each group, the islets were co-cultured for 48 h with drugs under static conditions with fentanyl alone, fentanyl ＋ 0.1 μg/mL naloxone or fentanyl ＋ 1.0 μg/mL naloxone. Cell viability was assessed by the MTT assay. Insulin release in response to low and high concentrations （2.8 mmol/L and 16.7 mmol/L, respectively） of glucose was investigated and electron microscopy morphological assessment was performed. RESULTS： Low- and high-glucose-stimulated insulin release in the control group was significantly higher than in groups I and II （62.33 ± 9.67 μIU vs 47.75 ± 8.47 μIU, 39.67 ± 6.18 μIU and 125.5 ± 22.04 μIU vs 96.17 ± 14.17 μIU, 75.17 ± 13.57 μIU, respectively, P 〈 0.01） and was lowest in group III （P 〈 0.01）. After adding 1 μg/mL naloxone, insulin release in groups II and II was not different from the control group. Electron microscopy studies showed that the islets were damaged by 30 ng/ml fentanyl. CONCLUSION： Fentanyl inhibited glucose-stimulated insulin release from rat islets, which could be prevented by naloxone. Higher concentrations of fentanyl significantly damaged β-cells of rat islets.

Conversing Rate from Morphine to Continuous Infusion of Fentanyl in Patients Suffering Cancer Pain

Objective： To investigate the proper conversing rate from morphine to continuous infusion of fentanyl in patients suffering cancer pain. Methods： A retrospective study was carried on in 20 patients with cancer pain in Shizuoka Cancer Center from Sep. 2002 to Nov. 2003. Pain intensity, adverse reactions, and satisfaction index of patients were evaluated. Results： The pain intensity was stable in 17 patients indicating good pain-control within 1 week after conversion and unstable in 3 patients after conversion suggesting poor pain-control. Fentanyl injection could alleviate side effects and increase the satisfaction index of patients. Conclusion： The equipotent ratio for conversion of low dose morphine to fentanyl injection was established as 72：1, and for non low dose morphine a ratio less than 72：1 was proposed to get stable pain-relieving effect. But the equipotent ratio for conversion of morphine to continuous infusion of fentanyl could not be determined. We must consider the morphine dose before the confirmation of the conversing rate.

Efficacy and Safety of Transdermal Fentanyl(TDF)in Treatment of Pain Caused by Interventional Embolization Therapy

Objective： Interventional embolization therapy is well accepted in cancer treatment, but patient may suffer from a moderate-to-severe pain after therapy and its quality of life （QoL） is influenced, this study is to observe the efficacy and safety of transdermal fentanyl （TDF） in the management of pain caused by interventional embolization therapy. Methods： Morphine 10mg and TDF 25μg/h were immediately used in 52 patients who had moderate-to-severe pain complicated by interventional embolization therapy, the pain intensity was evaluated by visual analogue scale （VAS）. If VAS≥4 at t2 h after treatment, the dosage of TDF added into 50 μg/h. At 0h, 12h, 24h, 72h, 1 week, 2 weeks after TD, the vas and adverse events were observed respectively. Result： There was an obvious decrease in VAS at 12h after TDF treatment in the patients of which only 9 patients used 50ug/h dosage after partial splenic embolization （PSE） therapy. Most patients got satisfactory pain relief both the TDF 25 μg/h and TDF 50 μg/h group （VAS 0-1）. The adverse events were nausea, vomiting and dizzy, especially in the TDF 50 μg/h group. No respiratory depression was observed and only one patient got retention of urine. Conclusion： TDF was effective and safe in the treatment of moderate-to-severe pain after interventional embolizafion therapy.

Membrane Separator Interface for Mass-Spectrometric Analysis of Desflurane, Propofol and Fentanyl in Plasma and Cerebrospinal Fluid

Mass-spectrometric interface for the measurement of anaesthetic agent concentration in biological fluids (blood plasma and cerebrospinal fluid) is described. Sampling of biological fluids was performed during balanced inhalational (desflurane, fentanyl) anaesthesia and total intravenous (propofol, fentanyl) anaesthesia. The described method for drug concentration measurement in biologic fluids does not require long-term sample processing before injecting the sample into mass-spectrometer interface, in contrast to chromatographic methods. A hydrophobic membrane was used in the interface to separate anaesthetic agents from biological fluids: inhalational anaesthetic desflurane, hypnotic propofol, analgesic fentanyl. A possibility to use the interface for measurement of desflurane and propofol absolute concentration in blood plasma and cerebrospinal fluid was demonstrated for the study of blood-brain barrier (BBB) properties.

Effect of pretreatment with different concertrations of morphine, fentanyl and tramadol on the differentiation of human helper T cells in vitro

Objective： To investigate and compare the .effects of different concentrations of morphine, fentanyl and tramadol on the differentiation of human adult helper T cells in vitro. Methods： Twenty out-patients without immune disease were selected and their peripheral blood was collected. Then the Whole blood of peripheral blood mononuclear cells （PBMCs） were pretreated with different concentration of morphine, fentanyl and tramadol for 24 h. The level of CD4^＋ IFN-γ^＋ IL-2^＋/CD4^＋ IL-4^＋ IL-10^＋ was analyzed by three-color flow cytometry, and the CD4^＋ CCR5^＋ and CD4^＋ CCR3 ^＋ cells were counted to observe the imbalance of Th2/Th2. Results： The number of Th2 increased significantly and the ratio of Th2/Th2 decreased dramatically compared with the control group, and there was a dose-dependent fashion in all drugs. Conclusion： Morphine, fentanyl and tramadol can direct Th0 cells toward Th2 differentiation, especially morphine and fentanyl.

Three-dimensional pharmacophore screening for fentanyl derivatives

Fentanyl is a highly selective u-opioid receptor agonist with high analgesic activity. Three-dimensional pharmacophore models were built from a set of 50 fentanyl derivatives. These were employed to elucidate ligand-receptor interactions using information derived only from the ligand structure to identify new potential lead compounds. The present studies demonstrated that three hydrophobic regions, one positive ionizable region and two hydrogen bond acceptor region sites located on the molecule seem to be essential for analgesic activity. The results of the comparative molecular field analysis model suggested that both steric and electrostatic interactions play important roles. The contributions from steric and electrostatic fields for the model were 0.621 and 0.379, respectively. The pharmacophore model provides crucial information about how well the common features of a subject molecule overlap with the hypothesis model, which is very valuable for designing and optimizing new active structures.

Effects of Dexamethasone, Clonidine, Tramadol and Nalbuphine on Fentanyl-Induced Hyperalgesia in Rats

Opioids are drugs used to alleviate pain. However, studies have demonstrated that these drugs can cause an increase in pain sensitivity, which is called opioid-induced hyperalgesia. The objective of this study was to describe the effects of dexamethasone, clonidine, tramadol and nalbuphine on fentanyl-induced hyperalgesia in rats. After obtaining approval from the Committee for the Ethical Use of Animals (CEUA), 36 male Wistar rats were divided into 6 groups: Group 1 (GCSSL) wherein the rats received 1 ml 0.9% saline solution in two injections;Group 2 (GFTSL), received fentanyl at a dose of 100 ug·kg-1 followed by 1 ml 0.9% saline solution via intraperitoneal;the remaining groups (3, 4, 5, 6) received fentanyl at a dose of 100 ug·kg-1 following doses via intraperitoneal: Group 3 (GFTDX), dexamethasone at a dose of 1.0 mg·kg-1;Group 4 (GFTCL), clonidine at a dose of 20 mg·kg-1;Group 5 (GFTTR), tramadol at a dose of 50 mg·kg-1, and Group 6 (GFTNB), nalbuphine at a dose of 5 mg·kg-1. Under general anestesia using isoflurane, the animals were submitted to a surgical incision. Hyperalgesia was evaluated by applying Von Frey filaments at 2 hours after the incision and on the 1st, 3rd and 5th days afterward. At 2 hours after the surgical procedure, there was lower intensity of pain in the fentanyl group (GFTSL) compared to the other groups, and on the fifth day there were no significant differences for pain intensity between groups. The results suggest the presence of fentanyl-induced hyperalgesia and efficacy in its reduction by dexamethasone, clonidine, tramadol and nalbuphine.