Vaccines as Immunotherapies for Substance Use Disorders.

Substance use disorders (SUD) present a worldwide challenge with few effective therapies except for the relative efficacy of opioid pharmacotherapies, despite limited treatment access. However, the proliferation of illicit fentanyl use initiated a dramatic and cascading epidemic of lethal overdoses. This rise in fentanyl overdoses regenerated an interest in vaccine immunotherapy, which, despite an optimistic start in animal models over the past 50 years, yielded disappointing results in human clinical trials of vaccines against nicotine, stimulants (cocaine and methamphetamine), and opioids. After a brief review of clinical and selected preclinical vaccine studies, the "lessons learned" from the previous vaccine clinical trials are summarized, and then the newest challenge of a vaccine against fentanyl and its analogs is explored. Animal studies have made significant advances in vaccine technology for SUD treatment over the past 50 years, and the resulting anti-fentanyl vaccines show remarkable promise for ending this epidemic of fentanyl deaths.

Perioperative analgesic effects of the erector spinae plane block with bupivacaine or bupivacaine-dexmedetomidine in dogs undergoing hemilaminectomy: A randomized controlled trial.

Objective: To compare the perioperative opioid requirements among dogs receiving an erector spinae plane (ESP) block with bupivacaine, with or without dexmedetomidine, and a control group. Animals and procedure: Thirty client-owned, healthy adult dogs undergoing hemilaminectomy were included in this randomized, prospective, blinded clinical study. Dogs were randomly assigned to 1 of 3 treatment groups: Group B, ESP block with bupivacaine; Group BD, ESP block with bupivacaine and dexmedetomidine; and Group C, control. Rescue intra- and postoperative analgesia consisted of fentanyl and methadone, respectively. Postoperative pain was evaluated using the short form of the Glasgow Composite Measure Pain Scale (CMPS-SF). Results: In Group BD, 0/10 dogs required intraoperative fentanyl, compared to 9/10 in Group C (P < 0.001), whereas 1/10 required postoperative methadone, compared to 9/10 in Group B (P = 0.003) and 10/10 in Group C (P < 0.001). The total amount of intraoperative fentanyl (µg/kg) was 0 (0 to 4) in Group B and 0 (0 to 0) in BD, compared to 6 (0 to 8) in C (P = 0.004 and P < 0.001, respectively). Postoperative methadone (mg/kg) required during the first 12 h was 0.5 (0 to 1.4) in Group B (P = 0.003) and 0 (0 to 0) in BD (P < 0.001), compared to C (P = 0.003 and P < 0.001, respectively). Conclusion: An ESP block with bupivacaine, with or without dexmedetomidine, was associated with a reduction in perioperative opioid consumption and provided effective acute pain control.

Effets analgésiques périopératoires du bloc des érecteurs du rachis avec de la bupivacaïne ou de la bupivacaïne-dexmédétomidine chez les chiens subissant une hémilaminectomie: un essai contrôlé randomisé. Objectif: Comparer les besoins périopératoires en opioïdes chez les chiens recevant un bloc des érecteurs de la colonne vertébrale (ESP) avec de la bupivacaïne, avec ou sans dexmédétomidine, et un groupe témoin. Animaux et procédure: Trente chiens adultes en bonne santé appartenant à des clients subissant une hémilaminectomie ont été inclus dans cette étude clinique randomisée, prospective et en aveugle. Les chiens ont été répartis au hasard dans 1 des 3 groupes de traitement: groupe B, bloc ESP avec bupivacaïne; groupe BD, bloc ESP avec bupivacaïne et dexmédétomidine; et groupe C, témoin. L'analgésie de secours peropératoire et postopératoire consistait respectivement en fentanyl et en méthadone. La douleur postopératoire a été évaluée à l'aide du formulaire abrégé de l'échelle de mesure de la douleur de Glasgow (CMPS-SF). Résultats: Dans le groupe BD, 0/10 chiens ont eu besoin de fentanyl peropératoire, contre 9/10 dans le groupe C (P < 0,001), tandis que 1/10 ont eu besoin de méthadone postopératoire, contre 9/10 dans le groupe B (P = 0,003) et 10/10 dans le groupe C (P < 0,001). La quantité totale de fentanyl peropératoire (µg/kg) était de 0 (0 à 4) dans le groupe B et de 0 (0 à 0) dans le groupe BD, contre 6 (0 à 8) dans le groupe C (P = 0,004 et P < 0,001, respectivement). La méthadone postopératoire (mg/kg) nécessaire au cours des 12 premières heures était de 0,5 (0 à 1,4) dans le groupe B (P = 0,003) et de 0 (0 à 0) dans le groupe BD (P < 0,001), par rapport au groupe C (P = 0,003). et P < 0,001, respectivement). Conclusion: Un bloc ESP avec de la bupivacaïne, avec ou sans dexmédétomidine, a été associé à une réduction de la consommation peropératoire d'opioïdes et a permis un contrôle efficace de la douleur aiguë.(Traduit par Dr Serge Messier).

Comparative study between remifentanil (or fentanyl) and dexmedetomidine for the analgesia of rhinoplasty: A meta-analysis of randomized controlled trials.

BACKGROUND: Remifentanil (or fentanyl) and dexmedetomidine may have some potential to improve the analgesia of rhinoplasty, and this meta-analysis aims to compare their efficacy for the analgesia of rhinoplasty. METHODS: PubMed, Embase, Web of Science, EBSCO, and Cochrane Library databases were systematically searched, and we included randomized controlled trials (RCTs) assessing the analgesic effect of remifentanil (or fentanyl) versus dexmedetomidine for rhinoplasty. RESULTS: Four RCTs were finally included in the meta-analysis. In patients undergoing rhinoplasty, remifentanil (or fentanyl) infusion and dexmedetomidine infusion resulted in similar good patient satisfaction (odd ratio [OR] = 2.71; 95% confidence interval [CI] = 0.63 to 11.64; P = .18), good surgeon satisfaction (OR = 1.68; 95% CI = 0.02 to 181.40; P = .83), extubation time (mean difference [MD] = 7.56; 95% CI = -11.00 to 26.12; P = .42), recovery time (MD = -2.25; 95% CI = -23.41 to 18.91; P = .83), additional analgesic requirement (OR = 0.16; 95% CI = 0 to 8.65; P = .37) and adverse events (OR = 8.50; 95% CI = 0.47 to 153.30; P = .15). CONCLUSIONS: Remifentanil (or fentanyl) and dexmedetomidine may have comparable analgesia for patients undergoing rhinoplasty.

Melatonin attenuates fentanyl - induced behavioral sensitization and circadian rhythm disorders in mice.

Melatonin is a neurohormone synthesized by the pineal gland to regulate the circadian rhythms and has proven to be effective in treating drug addiction and dependence. However, the effects of melatonin to modulate the drug-seeking behavior of fentanyl and its underlying molecular mechanism is elusive. This study was designed to investigate the effects of melatonin on fentanyl - induced behavioral sensitization and circadian rhythm disorders in mice. The accompanying changes in the expression of Brain and Muscle Arnt-Like (BMAL1), tyrosine hydroxylase (TH), and monoamine oxidase A (MAO-A) in relevant brain regions including the suprachiasmatic nucleus (SCN), nucleus accumbens (NAc), prefrontal cortex (PFC), and hippocampus (Hip) were investigated by western blot assays to dissect the mechanism by which melatonin modulates fentanyl - induced behavioral sensitization and circadian rhythm disorders. The present study suggest that fentanyl (0.05, 0.1 and 0.2 mg/kg) could induce behavioral sensitization and melatonin (30.0 mg/kg) could attenuate the behavioral sensitization and circadian rhythm disorders in mice. Fentanyl treatment reduced the expression of BMAL1 and MAO-A and increased that of TH in relevant brain regions. Furthermore, melatonin treatment could reverse the expression levels of BMAL1, MAO-A, and TH. In conclusion, our study demonstrate for the first time that melatonin has therapeutic potential for fentanyl addiction.

Gastrointestinal adverse effects associated with the use of intravenous oliceridine compared with intravenous hydromorphone or fentanyl in acute pain management utilizing adjusted indirect treatment comparison methods.

Background: In the absence of head-to-head comparative data from randomized controlled trials, indirect treatment comparisons (ITCs) may be used to compare the relative effects of treatments versus a common comparator (either placebo or active treatment). For acute pain management, the effects of oliceridine have been compared in clinical trials to morphine but not to fentanyl or hydromorphone. Aim: To assess the comparative safety (specifically differences in the incidence of nausea, vomiting and opioid-induced respiratory depression [OIRD]) between oliceridine and relevant comparators (fentanyl and hydromorphone) through ITC analysis. Methods: A systematic literature review identified randomized clinical trials with oliceridine versus morphine and morphine versus fentanyl or hydromorphone. The ITC utilized the common active comparator, morphine, for the analysis. Results: A total of six randomized controlled trials (oliceridine - 2; hydromorphone - 3; fentanyl - 1) were identified for data to be used in the ITC analyses. The oliceridine data were reported in two studies (plastic surgery and orthopedic surgery) and were also reported in a pooled analysis. The ITC focused on nausea and vomiting due to limited data for OIRD. When oliceridine was compared with hydromorphone in the ITC analysis, oliceridine significantly reduced the incidence of nausea and/or vomiting requiring antiemetics compared with hydromorphone (both orthopedic surgery and pooled data), while results in plastic surgery were not statistically significant. When oliceridine was compared with hydromorphone utilizing data from Hong, the ITC only showed a trend toward reduced risk of nausea and vomiting with oliceridine that was not statistically significant across all three comparisons (orthopedic surgery, plastic surgery and combined). An ITC comparing oliceridine with a study of fentanyl utilizing the oliceridine orthopedic surgery data and combined orthopedic and plastic surgery data showed a trend toward reduced risk that was not statistically significant. Conclusion: In ITC analyses, oliceridine significantly reduced the incidence of nausea and/or vomiting or the need for antiemetics in orthopedic surgery compared with hydromorphone and a non-significant trend toward reduced risk versus fentanyl.

Fentanyl abuse proportion in methadone maintenance treatment, and patients' knowledge about its risks.

INTRODUCTION: Fentanyl is not yet routinely monitored among methadone maintenance treatment (MMT) patients in Israel. We aimed 1. to evaluate urine fentanyl proportion changes over 3 years and characterize patients' characteristics 2. To study patients' self-report on fentanyl usage, and compare knowledge about fentanyl risk, before and following brief educational intervention. METHODS: Fentanyl in the urine of all current MMT patients was tested every 3 months year between 2021 and 2023, and patients with positive urine fentanyl were characterized. Current patients were interviewed using a fentanyl knowledge questionnaire (effects, indications, and risks) before and following an explanation session. RESULTS: Proportion of fentanyl ranged between 9.8 and 15.1%, and patients with urine positive for fentanyl (September 2023) were characterized as having positive urine for pregabalin, cocaine, and benzodiazepine (logistic regression). Of the current 260 patients (87% compliance), 78(30%) self-reported of fentanyl lifetime use ("Ever"), and 182 "never" use. The "Ever" group had higher Knowledge scores than the "Never", both groups improved following the explanatory session (repeated measure). The "Ever" group patients were found with urine positive for cannabis and benzodiazepine on admission to MMT, they were younger, did not manage to gain take-home dose privileges and had a higher fentanyl knowledge score (logistic regression). CONCLUSIONS: In the absence of routine fentanyl tests, a high knowledge score, shorter duration in MMT, benzodiazepine usage on admission, and current cannabis usage, may hint of the possibility of fentanyl abuse.

Fact vs. fiction: naloxone in the treatment of opioid-induced respiratory depression in the current era of synthetic opioids.

Opioid-induced respiratory depression (OIRD) deaths are ~80,000 a year in the US and are a major public health issue. Approximately 90% of fatal opioid-related deaths are due to synthetic opioids such as fentanyl, most of which is illicitly manufactured and distributed either on its own or as an adulterant to other drugs of abuse such as cocaine or methamphetamine. Other potent opioids such as nitazenes are also increasingly present in the illicit drug supply, and xylazine, a veterinary tranquilizer, is a prevalent additive to opioids and other drugs of abuse. Naloxone is the main treatment used to reverse OIRD and is available as nasal sprays, prefilled naloxone injection devices, and generic naloxone for injection. An overdose needs to be treated as soon as possible to avoid death, and synthetic opioids such as fentanyl are up to 50 times more potent than heroin, so the availability of new, higher-dose, 5-mg prefilled injection or 8-mg intranasal spray naloxone preparations are important additions for emergency treatment of OIRDs, especially by lay people in the community. Higher naloxone doses are expected to reverse a synthetic overdose more rapidly and the current formulations are ideal for use by untrained lay people in the community. There are potential concerns about severe withdrawal symptoms, or pulmonary edema from treatment with high-dose naloxone. However, from the perspective of first responders, the balance of risks would point to administration of naloxone at the dose required to combat the overdose where the risk of death is very high. The presence of xylazines as an adulterant complicates the treatment of OIRDs, as naloxone is probably ineffective, although it will reverse the respiratory depression due to the opioid. For these patients, hospitalization is particularly vital. Education about the benefits of naloxone remains important not only in informing people about how to treat emergency OIRDs but also how to obtain naloxone. A call to emergency services is also essential after administering naloxone because, although the patient may revive, they may overdose again later because of the short half-life of naloxone and the long-lasting potency of fentanyl and its analogs.

Lower extremity peripheral nerve block for total knee arthroplasty in a patient with chronic inflammatory demyelinating polyneuropathy: A case report.

RATIONALE: Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disorder that affects the peripheral nerves, leading to weakness and sensory symptoms. CIDP is a rare disease, and few studies have reported on anesthetic management in patients with this condition, especially the peripheral nerve block (PNB). Therefore, a safe and standardized anesthetic approach remains to be established. This case report aims to address this gap in evidence by documenting our experience with PNB in a patient with CIDP undergoing surgery. It contributes significantly to expanding the range of anesthetic options and enhancing perioperative outcomes for patients with CIDP. PATIENT CONCERNS: A 58-year-old woman diagnosed with CIDP was scheduled to undergo left total knee arthroplasty due to osteonecrosis. We anticipated postoperative pain and aggravation of neurological symptoms. DIAGNOSIS: CIDP. INTERVENTIONS: To manage the postoperative pain, we planned a combination of general anesthesia (GA) and lower extremity PNBs, viz. the tibial and femoral nerve blocks, supplemented with intravenous patient-controlled analgesia. An initial dose of fentanyl 50 µg was administered as analgesia. The tibial and femoral nerves were identified using a peripheral nerve stimulator in conjunction with an ultrasonic echo device while the patient was conscious, to minimize the risk of nerve injury. The tibial and femoral nerve blocks were performed with 20 mL of ropivacaine (0.25%) and dexamethasone 2.2 mg, respectively. Subsequently, we administered fentanyl and ketamine and initiated continuous infusion of remifentanil. Thereafter, propofol 120 mg was administered intravenously over a span of 1 minute, followed by continuous infusion at 4 mg/kg/h. Upon confirming loss of consciousness, we induced GA using a supraglottic airway device without using muscle relaxants. For postoperative analgesia, we administered acetaminophen 1000 mg. OUTCOMES: The patient experienced no pain immediately after surgery, and good analgesia was achieved subsequently without worsening of sensory symptoms during rehabilitation. LESSONS: We achieved effective anesthetic management in a patient with CIDP by combining GA with nerve stimulation and ultrasound-guided PNB. It is crucial to devise a personalized anesthesia plan that focuses on the patients' safety and comfort while minimizing risk in patients with CIDP.

Effectiveness of opioid switching for dyspnea and its predictors in cancer patients: a single-center retrospective observational study.

BACKGROUND: Morphine is the most used opioid for dyspnea, but other opioids such as oxycodone and fentanyl are increasingly used, and opioid switching to these is sometimes undertaken. No studies have verified the effectiveness of opioid switching for relief of dyspnea. We retrospectively investigated the effectiveness of opioid switching for dyspnea and its predictors. METHODS: All patients with opioid switching for dyspnea during hospitalization at Komaki City Hospital from January 2019 to August 2022 were included. Opioid switching was defined as a change to another opioid, and the assessment period for evaluating the effectiveness and adverse events of opioid switching was set as 1 week. Patients with Numeric Rating Scale or Japanese version of the Support Team Assessment Schedule reduction for dyspnea of at least 1, or with clear improvement based on medical records, were considered valid. Mitigating factors for dyspnea were identified using logistic regression analysis. RESULTS: Of the 976 patients with opioid switching, 57 patients had opioid switching for relief of dyspnea. Of these, opioid switching was effective in 21 patients (36.8%). In a multivariate analysis, older patients (odds ratio: 5.52, 95% CI: 1.50-20.20, P < 0.01), short prognosis for post-opioid switching (odds ratio: 0.20, 95% CI: 0.04-0.87, P = 0.03) and cachexia (odds ratio: 0.12, 95% CI: 0.02-0.64, P < 0.01) were significantly associated with opioid switching effects for dyspnea. There were no serious adverse events after opioid switching. CONCLUSION: This study indicates that opioid switching for dyspnea may have some effect. Furthermore, opioid switching for dyspnea may be more effective in older patients and less effective in terminally ill patients or in those with cachexia.

Expiratory Muscle Activity Counteracts Positive End-Expiratory Pressure and Is Associated with Fentanyl Dose in Patients with Acute Respiratory Distress Syndrome.

Rationale: Hypoxemia during mechanical ventilation might be worsened by expiratory muscle activity, which reduces end-expiratory lung volume through lung collapse. A proposed mechanism of benefit of neuromuscular blockade in acute respiratory distress syndrome (ARDS) is the abolition of expiratory efforts. This may contribute to the restoration of lung volumes. The prevalence of this phenomenon, however, is unknown. Objectives: To investigate the incidence and amount of end-expiratory lung impedance (EELI) increase after the administration of neuromuscular blocking agents (NMBAs), clinical factors associated with this phenomenon, its impact on regional lung ventilation, and any association with changes in pleural pressure. Methods: We included mechanically ventilated patients with ARDS monitored with electrical impedance tomography (EIT) who received NMBAs in one of two centers. We measured changes in EELI, a surrogate for end-expiratory lung volume, before and after NMBA administration. In an additional 10 patients, we investigated the characteristic signatures of expiratory muscle activity depicted by EIT and esophageal catheters simultaneously. Clinical factors associated with EELI changes were assessed. Measurements and Main Results: We included 46 patients, half of whom showed an increase in EELI of >10% of the corresponding Vt (46.2%; IQR, 23.9-60.9%). The degree of EELI increase correlated positively with fentanyl dosage and negatively with changes in end-expiratory pleural pressures. This suggests that expiratory muscle activity might exert strong counter-effects against positive end-expiratory pressure that are possibly aggravated by fentanyl. Conclusions: Administration of NMBAs during EIT monitoring revealed activity of expiratory muscles in half of patients with ARDS. The resultant increase in EELI had a dose-response relationship with fentanyl dosage. This suggests a potential side effect of fentanyl during protective ventilation.

Analgesic Efficacy of Epidural Patient-Controlled Analgesia on Cancer Pain: A Retrospective Observational Study.

BACKGROUND: In patients with severe cancer pain, systemic analgesics are often refractory or have limited application due to the side effects of opioids. In these cases, epidural analgesia may be effective. However, data on the effects of epidural patient-controlled analgesia (PCA) on cancer pain are limited. OBJECTIVES: To evaluate the analgesic efficacy of epidural PCA in patients with cancer pain through a retrospective chart review. STUDY DESIGN: Retrospective analysis. SETTING: A single academic center in Daegu, South Korea. METHODS: The analgesic efficacy of epidural PCA on cancer pain was analyzed in patients who underwent epidural PCA using a disposable balloon pump with a flow regulator between 2012 and 2021. The pump was filled with a 600-mL mixture of 6 ampoules of 0.2% ropivacaine, 1 mg fentanyl, and normal saline. For the first use of epidural PCA, the basal rate, bolus dose, and lockout time were set as 4 mL/h, 2 mL, and 15 min, respectively. The basal rate was increased and decreased depending on the degree of pain relief effect and occurrence of side effects, respectively. To increase the usage time of epidural PCA and reduce the patient's cost burden, the fentanyl dose was increased by 1 mg when the disposable balloon pump was replaced with a new one after exhaustion of the drug if no side effects from the previous dose were observed. Analgesic efficacy was confirmed by comparing the number of types and the total amount of opioids used in patients before and after epidural PCA application in terms of the equivalent dose of oral morphine. RESULTS: Epidural catheterization was performed 105 times, and PCA was refilled 257 times in 88 patients. On average, epidural catheterization was performed 1.2 ± 0.4 (1-3) times, and epidural PCA was refilled 3.2 ± 2.3 (1-11) times per patient. The mean duration of PCA use was 15.6 ± 13.4 (1-82) days. The mean number of opioid types used the day before the procedure and the mean smallest number of opioids used per day up to 5 days after the procedure were 3.4 ± 1.2 and 2.4 ± 1.4, respectively (P < 0.05). The total amount of opioids used the day before the procedure and the smallest total amount of opioids used per day up to 5 days after the procedure were converted into oral morphine equivalent doses, respectively, and the mean doses were 449.5 ± 555.9 and 331.9 ± 462.8 mg, respectively (P < 0.05). LIMITATIONS: The study results are the author's observations from a single center. Epidural PCA was performed only on hospitalized patients. Individual differences were not considered in the composition of drugs for PCA. Transmucosal immediate-release fentanyl was not accurately converted to oral morphine; thus, it was excluded from the analysis of the total amount used, and the effect of adjuvant analgesics could not be considered. CONCLUSION: Epidural PCA using subcutaneous tunneling is a useful cancer pain control method. Furthermore, it can be safely used for a longer duration owing to its low infection risk.

Deaths From Drug Overdoses What School Nurses Need to Know.

Drug overdose deaths in pre-teen and adolescent students have risen over the past several years, causing increasing concerns in our society, along with concerns over the rise in availability of more counterfeit pills and illegally manufactured fentanyl. School nurses interface regularly with pre-teen and adolescent students and therefore are in a position to recognize students at risk for illicit drug use and provide important education to students, staff, parents, and the community. The purpose of this article is to briefly discuss risk factors for opioid misuse and to provide recommendations for interventions school nurses can use, including collaboration with other school and community leaders, to help prevent opioid overdose and death in pre-teen and adolescence.

A randomized controlled trial of propofol-remifentanil total intravenous anesthesia and sevoflurane-fentanyl anesthesia on early postoperative fatigue in patients undergoing laparoscopic colorectal surgery.

PURPOSE: Even after uncomplicated surgery, postoperative fatigue prevalence has been reported to be 30-80% for various surgeries. We evaluated postoperative fatigue according to anesthetic technique in patients who underwent colorectal surgery. METHODS: One hundred thirty patients who underwent colorectal surgery were randomly assigned to either propofol-remifentanil total intravenous anesthesia (propofol-remifentanil group, n = 65) or sevoflurane-fentanyl anesthesia (sevoflurane-fentanyl group, n = 65). The primary outcome was the prevalence of postoperative fatigue, as defined by the Chalder Fatigue Questionnaire (total score ≥ 16), at 24 h postoperatively. Secondary outcomes were early postoperative complications during hospitalization and laboratory examination. RESULTS: The final analyses included 127 patients. The prevalence of postoperative fatigue on the 1st postoperative day was lower in the propofol-remifentanil group than the sevoflurane-fentanyl group: 56.3% (36/64) in the propofol-remifentanil group and 73.0% (46/63) in the sevoflurane-fentanyl group (relative risk [RR] = 0.77, 95% confidence interval [CI] 0.59-1.00; P = 0.048). However, there was no difference between the two groups in postoperative fatigue at postoperative day 3. Other postoperative outcomes including the severity of pain and the incidence of nausea/vomiting were not different between the two groups, but postoperative atelectasis on chest X-ray was higher in the sevoflurane-fentanyl group (2/64 [3.1%] vs. 9/63 [14.3%], P = 0.025). C-reactive protein change from preoperative to postoperative day 1 and 5 was significantly lower in the propofol-remifentanil group (P = 0.044). CONCLUSION: Propofol-remifentanil total intravenous anesthesia was associated with reduced postoperative fatigue at the 1st postoperative day compared with sevoflurane-fentanyl anesthesia. Clinical trial The Korean Clinical Research Registry (study identifier: KCT0006917, principal investigator's name: MiHye Park, date of registration: January 12, 2022).

Comparison of the Effects of OPRM1 A118G Polymorphism Using Different Opioids: A Prospective Study.

CONTEXT: µ-opioid receptor gene (OPRM1) A118G polymorphism (rs1799971) causes loss of N-glycosylation sites at the extracellular domain of µ-opioid receptors. G-allele carriers show a limited response to morphine; however, studies investigating the impact of A118G polymorphism on the efficacy of opioids other than morphine are limited. OBJECTIVE: To compare the impact of A118G polymorphism on the efficacy of various opioids. METHODS: This prospective cohort study enrolled 222 in-patients administered one of the following opioid therapies for cancer pain as part of an opioid introduction or rotation strategy: tapentadol extended-release tablets, methadone tablets, hydromorphone controlled-release tablets, oxycodone controlled-release tablets, or transdermal fentanyl patches. The impact of A118G polymorphism on the difference in the Brief Pain Inventory-Short Form score on days three, seven, and 14 from baseline was compared among the groups. RESULTS: Overall, 81, 74, and 67 patients had the AA, AG, and GG genotypes, respectively, with an OPRM1 A118G G-allele variant frequency of 0.47. The reduction in the Brief Pain Inventory-Short Form score after opioid therapy initiation did not differ significantly among the patients with the three A118G genotypes treated with tapentadol (p = 0.84) or methadone (p = 0.97), whereas it was significantly smaller in G-allele carriers than that in AA homozygous patients treated with hydromorphone (p < 0.001), oxycodone (p = 0.031), or fentanyl (p < 0.001). CONCLUSION: Tapentadol and methadone may be more suitable than hydromorphone, oxycodone, and fentanyl for G-allele carriers due to their dual mechanism of action and low susceptibility to OPRM1 A118G polymorphism.

Cancer-related breathlessness: opioids other than morphine - comprehensive literature review.

INTRODUCTION: Although there is low-quality evidence, there has been an increase in publications on the experience of evaluating and managing cancer-related breathlessness using opioids other than morphine. METHODS: The author conducted a non-systematic literature review in the PubMed/Medline and Embase until 4 October 2022. Eligible studies have evaluated the efficacy of opioids other than morphine for cancer-related breathlessness. Studies focused on sedation, anaesthesia, paediatric patients, opioid toxicity or basic research were excluded. Reviews/meta-analyses and non-English language publications were also excluded. RESULTS: A total of 1556 records were identified, of which 23 studies including 469 patients who were treated with fentanyl (n=223), oxycodone (n=171) and hydromorphone (n=75) were considered eligible. Six phase II randomised clinical trials (RCTs), four observational studies and four case reports of fentanyl were found. For breathlessness on exertion, fentanyl yielded promising results, but no RCT showed significant superiority of fentanyl to placebo or morphine. For terminal breathlessness, three RCTs, five non-randomised or observational studies and one case report on oxycodone or hydromorphone were found. Although the results of the observational studies suggested that oxycodone and hydromorphone might be effective alternatives to morphine, the superiority over placebo or non-inferiority to morphine had not been demonstrated in the RCTs. CONCLUSION: As an alternative to morphine, the author recommends fentanyl for breathless crisis or breathlessness on exertion, and oxycodone or hydromorphone for terminal breathlessness in advanced cancer. Larger and well-designed studies based on firm research policies are needed to confirm this current knowledge.

Finding predictors for successful opioid response in cancer patients: An analysis of data from four randomized controlled trials.

CONTEXT: There is no consensus on which "strong" (or step 3 WHO analgesic ladder) opioid to prescribe to a particular patient with cancer-related pain. A better understanding of opioid and patient characteristics on treatment response will contribute to a more personalized opioid treatment. OBJECTIVES: Assessment of potential predictors for successful opioid treatment response in patients with cancer pain. METHODS: An international partnership between four cancer pain research groups resulted in a combined individual-level database from four relevant randomized controlled trials (RCTs; n = 881). Together, these RCTs investigated the short-term (1 week) and medium-term (4 or 5 weeks) treatment responses for morphine, buprenorphine, methadone, oxycodone, and fentanyl. Candidate predictors for treatment response were sex, age, pain type, pain duration, depression, anxiety, Karnofsky performance score, opioid type, and use of anti-neuropathic drug. RESULTS: Opioid type and pain type were found statistically significant predictors of short-term treatment success. Sex, age, pain type, anxiety, and opioid type were statistically, significantly associated with medium-term treatment success. However, these models showed low discriminative power. CONCLUSION: Fentanyl and methadone, and mixed pain were found to be statistically significant predictors of treatment success in patients with cancer-related pain. With the predictors currently assessed our data did not allow for the creation of a clinical prediction model with good discriminative power. Additional - unrevealed - predictors are necessary to develop a future prediction model.

Intravenous Ketamine for Pain Control in First-Trimester Surgical Abortion: Interim Analysis of a Randomized Controlled Trial.

OBJECTIVES: Surgical abortion is common, with most completed in the first trimester. Gold standard pain control is intravenous (IV) fentanyl and midazolam, requiring continuous cardio-respiratory monitoring, a potential challenge where this monitoring is unavailable. Ketamine is a sedative and analgesic without the cardio-respiratory depression risk associated with IV opioids, representing a potential alternative. Investigating non-opiate pain control methods is imperative given the context of the opioid crisis. This is an interim analysis of 45 participants from a randomized controlled trial comparing IV ketamine, oral morphine, and IV fentanyl for pain control in first-trimester surgical abortion. We hypothesize that ketamine will provide better pain control than morphine. METHODS: This is a double-blind, single-centre superiority trial of 3 parallel groups. Participants were ≥18 years old with confirmed intrauterine pregnancy of gestational age <12 weeks. Pain was assessed using the Visual Analogue Scale and the Wong-Baker Faces Pain Rating Scale. RESULTS: In total, 2 participants were excluded post-randomization for 43 treated. Findings indicate that ketamine (n = 14; M = 0.7; 95% CI 0.1-1.3) provides better intra-operative pain control than morphine (n = 15, M = 4.4, 95% CI 2.9-5.9) and fentanyl (n = 14; M = 4.3; 95% CI 3.0-5.6; P < 0.001). The ketamine group was more satisfied with the anaesthetic method than the morphine group (P = 0.017). No group experienced serious adverse events. CONCLUSIONS: Findings support continuation of the randomized controlled trial and highlight ketamine as a compelling non-opiate pain control option in first-trimester surgical abortion. Ketamine use may represent more optimal pain control in settings where continuous cardio-respiratory monitoring is unavailable.

Open-label investigation of rapid initiation of extended-release buprenorphine in patients using fentanyl and fentanyl analogs.

BACKGROUND AND OBJECTIVES: Synthetic opioids, including fentanyl and fentanyl analogs, account for over 70,000 annual overdose deaths in the United States, but there is limited information examining methods of induction and maintenance outcomes for buprenorphine treatment of patients with opioid use disorder (OUD) using these opioids. METHODS: A secondary analysis of results grouped by fentanyl use status was completed for an open-label study with rapid induction of extended-release buprenorphine in the inpatient research unit. Eligible participants received a single 4 mg dose of transmucosal buprenorphine (BUP-TM) followed by an extended-release buprenorphine 300 mg injection ([BUP-XR]) after approximately 1 h. An extension study continued follow-up up to 6 months (6 monthly injections). RESULTS: Among participants with fentanyl-positive urine samples (FEN+; n = 19), all received BUP-TM, 17 received BUP-XR, 13 elected to receive a second BUP-XR injection, and 10 received all six scheduled injections. Among participants with fentanyl-negative samples (FEN-; n = 7), all received BUP-TM and BUP-XR, four elected to receive a second injection, and two participants received all six scheduled injections. Induction day clinical opioid withdrawal scale (COWS) scores were similar for FEN+ and FEN- groups. In the FEN+ group, mean COWS scores fell to below 5 within 24 h of BUP-XR injection. DISCUSSION AND CONCLUSIONS: The treatment of individuals with OUD using fentanyl with a rapid 1-day induction to BUP-XR 300 mg injection is feasible and well-tolerated. SCIENTIFIC SIGNIFICANCE: A prospective trial of participants grouped by fentanyl use status at induction demonstrates comparable patient retention and clinical response following single-day induction of BUP-XR in participants who are FEN+ and FEN-.