Pharmacokinetics, Fecal Output, and Grimace Scores in Rabbits Given Long-acting Buprenorphine or Fentanyl for Postsurgical Analgesia.

The New Zealand white rabbit (Oryctolagus cuniculus) is a frequently used surgical model. Pain management after surgery is a critical aspect of animal welfare. Recently, a long-acting buprenorphine formulation (Ethiqa XR; EXR) was approved for use in rats and mice but has not yet been investigated in rabbits. The current study aimed to determine whether a single subcutaneous dose of 0.15mg/kg of EXR could achieve and maintain therapeutic buprenorphine plasma concentrations (0.1ng/mL) for 72h in male and female rabbits. We also evaluated the safety profiles of EXR and the fentanyl patch (FP) by assessing fecal output after surgery, because opioids are known to decrease intestinal motility. Behavior and pain scores were compared for rabbits that received either EXR or the FP after undergoing an annulus puncture procedure to induce osteoarthritis. EXR at 0.15mg/kg SC provided a shorter time to onset and sustained analgesia for 72h in male and female rabbits, whereas the FP provided suboptimal analgesia after 48h. Both EXR and FP reduced fecal output after surgery. Output returned to baseline levels within 72h for the EXR group and remained slightly below baseline at 96h after surgery for the fentanyl group. Grimace pain scores revealed no significant difference between treatment groups. These results suggest that EXR is a safe and effective option for postoperative pain management in rabbits.

Relationship between opioid cross-tolerance during buprenorphine stabilization and return to opioid use during buprenorphine dose tapering.

RATIONALE: Opioid injection drug use (IDU) has been linked to a more severe pattern of use (e.g. tolerance, overdose risk) and shorter retention in treatment, which may undermine abstinence attempts. OBJECTIVES: This secondary data analysis of four human laboratory studies investigated whether current opioid IDU modulates subjective abuse liability responses to high-dose hydromorphone during intermediate-dose buprenorphine stabilization (designed to suppress withdrawal but allow surmountable agonist effects), and whether hydromorphone response magnitude predicts latency of return to opioid use during buprenorphine dose-tapering. METHODS: Regular heroin users not currently seeking treatment (n = 54; 29 current injectors, 25 non-injectors) were stabilized on 8-mg/day sublingual buprenorphine and assessed for subjective responses (e.g. 'liking', craving) to hydromorphone 24-mg intramuscular challenge (administered 16-hr post-buprenorphine) under randomized, double-blinded, controlled conditions. A subgroup (n = 35) subsequently completed a standardized 3-week outpatient buprenorphine dose-taper, paired with opioid-abstinent contingent reinforcement, and were assessed for return to opioid use based on thrice-weekly urinalysis and self-report. RESULTS: During buprenorphine stabilization, IDU reported lower 'liking' of buprenorphine and post-hydromorphone peak 'liking', 'good effect' and 'high' compared to non-IDU. Less hydromorphone peak increase-from-baseline in 'liking' (which correlated with less hydromorphone-induced craving suppression) predicted significantly faster return to opioid use during buprenorphine dose-tapering. CONCLUSIONS: In these buprenorphine-stabilized regular heroin users, IDU is associated with attenuated 'liking' response (more cross-tolerance) to buprenorphine and to high-dose hydromorphone challenge and, in turn, this cross-tolerance (but not IDU) predicts faster return to opioid use. Further research should examine mechanisms that link cross-tolerance to treatment response.

Multicentered masked placebo-controlled phase 2 clinical study of an extended duration transdermal buprenorphine solution for postoperative pain in cats.

A prospective, double-masked, placebo-controlled, multicentered phase 2 clinical study was conducted to select the transdermal buprenorphine solution (TBS) dosage for the control of postoperative pain in cats. One-hundred fifteen (115) cats were randomized to a single topical dose of placebo solution, low-TBS dosage (1.91-2.07 mg/kg) or high-TBS dosage (4.27-4.88 mg/kg) prior to surgical reproductive sterilization in conjunction with forelimb onychectomy. The low- and high-TBS doses were applied 2-4 and 1-2 hours prior to surgery. Interactive pain assessments and physiological variables were quantified through 96 hours post-anesthetic recovery and rescue analgesia was administered any time that analgesia was considered inadequate. Cats requiring rescue analgesia were considered treatment failures. The estimated overall treatment success rates from generalized linear mixed effects model analysis were 0.10 (95% CI: [0.02-0.36]), 0.56 (95% CI: [0.25-0.83]), 0.71 (95% CI: [0.38-0.91]) in the placebo-, low-, and high-TBS dose groups, respectively. Success rates for both TBS treatment groups were superior to placebo. Adverse events were infrequent in all treatment groups although the postoperative body temperatures over the duration of the study were on average 0.31 (95% CI: [0.08-0.55]) and 0.30 (95% CI: [0.05-0.53]) °C higher in low- and high-TBS dose cats, respectively, compared to placebo. It is concluded that both the low- and high-TBS dosages were safe and effective. The high-TBS dosage resulted in a greater proportion of treatment successes over 96 h, had a more acceptable preoperative application time of 1-2 h prior to surgery, and was therefore selected for further study.

Multicentered masked placebo-controlled phase 3 clinical study of an extended duration transdermal buprenorphine solution for post-operative pain in cats.

A prospective, double masked, placebo-controlled, multicentered phase 3 clinical study was conducted to evaluate the safety and effectiveness of transdermal buprenorphine solution (TBS) for the control of post-operative pain in cats. A total of 228 cats from 12 US investigational sites met the enrollment criteria of which 107 placebo- and 112 TBS-treated cats were included into the per protocol efficacy analysis. The dose of TBS was 8 mg (0.4 ml) to cats 1.2 to 3 kilograms and 20 mg (1 ml) to cats >3 to 7.5 kilograms applied topically to the dorsal unclipped cervical skin 1-2 h prior to the undergoing elective surgical reproductive sterilization in conjunction with forelimb onychectomy. Interactive pain assessments and physiological variables were quantified through 96 h following recovery from anesthesia, and rescue analgesia was administered any time that pain control was scored inadequate. Cats requiring rescue analgesia or experiencing an adverse event suspected to be treatment related were considered treatment failures. Sixty-five and 23 cats were considered treatment failures in the placebo and TBS groups, respectively, with most occurring on the day of surgery. The treatment success rates were 0.40 (95% confidence interval [CI]: [0.28-0.53]) and 0.81 (95% CI: [0.70-0.89]) in the placebo and TBS groups, respectively, and the difference was significant (p < .05). Adverse events occurred at a similar frequency and were not clinically meaningful in either treatment group. The post-operative body temperatures over the duration of the study were on average 0.35 (95% CI: [0.20-0.50]) °C higher than baseline in TBS-treated cats and were not clinically meaningful, an observation typical of opioids in cats. These results serve as substantial evidence that TBS is safe and effective for the control of orthopedic and soft tissue post-operative pain in cats when a single topical dose is applied 1-2 h prior to surgery.

Complete opioid transition to sublingual Buprenorphine after abdominal surgery is associated with significant reductions in opioid requirements, but not reduction in hospital length of stay: a retrospective cohort study.

BACKGROUND: The use of sublingual buprenorphine (SLBup) for acute pain after major abdominal surgery may offer the potential advantages of unique analgesic properties and more reliable absorption during resolving ileus. We hypothesized that complete opioid transition to SLBup rather than oral oxycodone (OOxy) in the early postoperative period after major abdominal surgery would reduce hospital length of stay, and acute pain and total OMEDD (Oral Morphine Equivalent Daily Dose) requirements in the first 24 h from post-parenteral opioid transition. METHODS: We reviewed 146 patients who had undergone elective and emergency abdominal surgery under our quaternary referral centre's Upper Gastro-Intestinal and Colo-Rectal Surgical Units 6 months before and after the introduction of complete postoperative transition to sublingual buprenorphine, rather than oral oxycodone, in July 2017. Our primary endpoint was 24-hourly post-transition OMEDDs; secondary endpoints were 24-hourly post-transition Mean NRS-11 pain scores on movement (POM) and length of hospital stay (LOS). Univariate analysis and linear multivariate regression analyses were used to quantify effect size and identify surgical, patient & other analgesic factors associated with these outcome measures. RESULTS: Patients transitioning to SLBup had reduced 24-hourly post-transition OMEDD requirements on postoperative day 2 (POD) (26 mg less, p = 0.04) and NRS-11 POM at POD1 (0.7 NRS-11 units less, p = 0.01). When adjusting for patient, surgical and special analgesic factors, SLBup was associated with a similar reduction in OMEDDs (Unstandardised beta-coefficient -26 mg, p = 0.0001), but not NRS-11 POM (p = 0.47) or hospital LOS (p = 0.16). CONCLUSIONS: Our change of practice from use of OOxy to SLBup as primary transition opioid from patient-controlled analgesia delivered full opioid agonists was associated with a clinically significant decrease in 24-hourly post-parenteral opioid transition OMEDDs and improved NRS-11 POM, but without an association with hospital LOS after major abdominal surgery. Further prospective randomized work is required to confirm these observed associations and impact on other important patient-centred outcomes.

Inhibiting Kiss1 Neurons With Kappa Opioid Receptor Agonists to Treat Polycystic Ovary Syndrome and Vasomotor Symptoms.

CONTEXT: Recent evidence suggests that vasomotor symptoms (VMS) or hot flashes in the postmenopausal reproductive state and polycystic ovary syndrome (PCOS) in the premenopausal reproductive state emanate from the hyperactivity of Kiss1 neurons in the hypothalamic infundibular/arcuate nucleus (KNDy neurons). OBJECTIVE: We demonstrate in 2 murine models simulating menopause and PCOS that a peripherally restricted kappa receptor agonist (PRKA) inhibits hyperactive KNDy neurons (accessible from outside the blood-brain barrier) and impedes their downstream effects. DESIGN: Case/control. SETTING: Academic medical center. PARTICIPANTS: Mice. INTERVENTIONS: Administration of peripherally restricted kappa receptor agonists and frequent blood sampling to determine hormone release and body temperature. MAIN OUTCOME MEASURES: LH pulse parameters and body temperature. RESULTS: First, chronic administration of a PRKA to bilaterally ovariectomized mice with experimentally induced hyperactivity of KNDy neurons reduces the animals' elevated body temperature, mean plasma LH level, and mean peak LH per pulse. Second, chronic administration of a PRKA to a murine model of PCOS, having elevated plasma testosterone levels and irregular ovarian cycles, suppresses circulating levels of LH and testosterone and restores normal ovarian cyclicity. CONCLUSION: The inhibition of kisspeptin neuronal activity by activation of kappa receptors shows promise as a novel therapeutic approach to treat both VMS and PCOS in humans.

Sustained release buprenorphine effectively attenuates postoperative hypersensitivity in an incisional pain model in neonatal rats (Rattus norvegicus).

Despite the need for safe and effective postoperative analgesia in neonates, research regarding pain management in neonatal rodents is relatively limited. Here, we investigate whether sustained release buprenorphine (Bup SR) effectively attenuates thermal hypersensitivity in a neonatal rat model of incisional pain. Male and female postnatal day 3 Sprague Dawley rat pups (n = 34) were randomly assigned to one of four treatment groups: 1) saline (control), 0.1 mL, once subcutaneously (SC); 2) buprenorphine HCl (Bup HCl), 0.05 mg/kg, once SC; 3) low dose Bup SR (low-SR), 0.5 mg/kg, once SC; 4) high dose Bup SR (high-SR), 1 mg/kg, once SC. Pups were anesthetized with sevoflurane and a 0.5-cm long skin incision was made over the left lateral thigh. The underlying muscle was dissected and closed using surgical glue. Thermal hypersensitivity testing was performed at 24 h prior to surgery and subsequently at 1, 4, 8, 24, and 48 h post-surgery using an infrared diode laser. Thermal hypersensitivity was attenuated at 1 h post-surgery in the Bup HCl group, while it was attenuated through the entire postoperative period in both low-SR and high-SR groups. This data suggests that a single dose of low-SR (0.5 mg/kg) or high-SR (1 mg/kg) effectively attenuates thermal hypersensitivity for at least 8 h in neonatal rat pups.

Exploración de la eficacia analgésica de dos parches transdérmicos analgésicos de opioides, buprenorfina y fentanilo, según sus variaciones de dosis en el control del dolor en pacientes paliativos oncológicos / Exploration of the analgesic efficacy of two-transdermal analgesic patches of opioids, buprenorphine and fentanyl, according to their dose variations in pain control in palliative cancer patients

Objetivo: El presente trabajo de investigación tuvo como objetivo explorar la eficacia analgésica mediante la comparación de la respuesta analgésica de los parches transdérmicos (PTD) de buprenorfina y fentanilo en dolor oncológico y patrón de uso. Material y Método: Se obtuvieron los datos y variables desde los registros clínicos de pacientes ingresados a la Unidad de Cuidados Paliativos (UCP) del Instituto Nacional del Cáncer (INC) que estaban bajo tratamiento en mayo del 2017. Se incluyó en este estudio a 78 pacientes con PTD, que representan el 13% de los pacientes en control mensual. De estos, 66 estaban bajo tratamiento con buprenorfina y 8 bajo tratamiento con fentanilo. Resultados: Los resultados mostraron que el PTD de buprenorfina se utiliza más frecuentemente que el de fentanilo. El principal motivo de rotación fue dolor no controlado, seguido por imposibilidad de contar con la administración por vía oral. En pacientes con mayores intensidades de dolor somático o visceral se indicó fentanilo y en aquellos con componente neuropático se prefirió el uso de buprenorfina. PTD de fentanilo fue indicado en dosis mayores que buprenorfina, incluso al comparar sus dosis equianalgésicas, siendo la variación de dosis alta para ambos parches: aumentó en promedio 257%. Se logró una mejor respuesta analgésica con buprenorfina, con una variación de intensidad de escala numérica verbal (ENV) de 2,94 y 1,88 puntos de promedio para buprenorfina y fentanilo, respectivamente. Adicionalmente, se presentó mayor reacción local dérmica con fentanilo. Conclusiones: Se evidenció diferencias en patrón de uso y, a diferencia de lo esperado, se obtuvo una mejor eficacia analgésica con buprenorfina. Datos que deben ser corroborados en estudios con mayor número de pacientes bajo tratamiento con fentanilo.

Objective: This study aims to explore analgesic efficacy comparisons of buprenorphine and fentanyl transdermal patches (TDP) in cancer pain and it's usage pattern. Material and Method: Data and variables were collected from patient's clinical reports who were admitted in the National Cancer Institute's (NCI) Palliative Care Unit (PCU) and were under treatment with TDP in May 2017. 78 TDP patients were studied and represented 13% of the monthly control patients in the PCU. Of these, 66 were under buprenorphine treatment and 8 under fentanyl treatment. Results: The results showed that buprenorphine TDP is more frequently used than fentanyl TDP, and the main reason for exchange between them was uncontrolled pain, followed by oral administration impossibility. Fentanyl TDP was indicated in patients with higher somatic or visceral pain intensities and Buprenorphine TDP was preferred in patients with neuropathic pain. Fentanyl TDP was indicated in higher doses than buprenorphine, even when comparing its equianalgesic doses, the dose variation was high for both patches throughout the treatment: it increased on average by 257%. A better analgesic response was achieved with buprenorphine, with a variation of intensity of the Verbal Numerical Scale (VNS) of 2.94 and 1.88 average points, for buprenorphine and fentanyl respectively. Additionally, there was a higher local dermal reaction with fentanyl TDP. Conclusions: Differences in usage patterns were evidenced and, unlike what was expected, better analgesic efficacy was obtained with buprenorphine TDP. This data should be corroborated in receiving fentanyl treatment.

Real-world reduction in healthcare resource utilization following treatment of opioid use disorder with reSET-O, a novel prescription digital therapeutic.

INTRODUCTION: Buprenorphine medication assisted treatment (B-MAT) adherence for opioid use disorder (OUD) is suboptimal. reSET-O, an FDA-cleared prescription digital therapeutic, delivers neurobehavioral therapy (community-reinforcement approach+fluency training+contingency management) to B-MAT-treated OUD patients. METHODS: This retrospective claims study (10/01/2018-10/31/2019) evaluated healthcare resource utilization up to 6 months before/after reSET-O initiation. Repeated-measures negative binomial models compared incidences of encounters/procedures. Net change in costs was assessed. RESULTS: Among 351 patients (mean age 37; 59.5% female; 82.6% Medicaid), 334 had pharmacy claims and 240 (71.9%) received buprenorphine pre-/post-index (medication possession ratio 0.73 and 0.82, respectively; P = 0.004). Facility encounters decreased, with 45 fewer inpatient (P = 0.024) and 27 fewer emergency department (ED) visits (P = 0.247). Clinical encounters with largest changes were drug testing (638 fewer; P < 0.001), psychiatry (349 fewer; P = 0.036), case management (176 additional; P = 0.588), other pathology/laboratory (166 fewer; P = 0.039), office/other outpatient (154 fewer; P = 0.302), behavioral rehabilitation (111 additional; P = 0.124), alcohol/substance rehabilitation (96 fewer; P = 0.348), other rehabilitation (66 fewer; P = 0.387), mental health rehabilitation (61 additional; P = 0.097), and surgery (60 fewer; P = 0.070). Changes in facility/clinical encounters saved $2,150/patient. CONCLUSION: reSET-O initiation was associated with fewer inpatient, ED, and other clinical encounters, increased case management/rehabilitative services, and lower net costs over six months. EXPERT OPINION: Real-world evidence is helpful in evaluating the effectiveness of interventions in usual-care conditions, outside of controlled research environments. Large observational studies based on health care claims are important to understand the actual pharmacoeconomic and outcomes impact of interventions at the health care system and population level.

Retrospective analysis of heroin detoxification with buprenorphine in a psychiatric hospital in Japan.

AIM: We assessed the efficacy of buprenorphine replacement taper therapy in a psychiatric hospital in Japan. METHODS: Based on the medical records, a retrospective analysis was performed to evaluate the outcomes of buprenorphine replacement taper therapy in 106 subjects with heroin dependence. RESULTS: We found that replacement and taper therapy with buprenorphine could significantly reduce withdrawal symptoms during detoxification. In addition, the completion rate of detoxification was significantly improved and the length of hospital stay was significantly reduced relative to those who received conventional treatment without buprenorphine. However, the readmission rate increased after the introduction of detoxication therapy with buprenorphine. CONCLUSION: The present findings suggest not only the efficacy and safety of buprenorphine replacement and taper therapy, but also the requirement for maintenance therapy for individuals with heroin dependence.

A narrative review of buprenorphine in adult cancer pain.

INTRODUCTION: Adult cancer pain is a disease state battled on a global scale. Proper pain management is essential to prevent health complications and promote patient well-being. Due to the opioid misuse crisis in the United States, providers are looking for alternatives to traditional opioids used for adult cancer pain. Buprenorphine has a unique pharmacologic profile, allowing it to be delivered in noninvasive ways; thus, it offers an alternative to traditional options. Randomized controlled trials have shown improved pain scores with transdermal buprenorphine, and they showed reductions in pain scores and increased improvement in quality of life scores versus other opioids. Sublingual buprenorphine has more limited, but promising data for reducing cancer pain. AREAS COVERED: We provide a narrative review of pathophysiological pathways of pain in cancer, how they are treated, and the unique properties of buprenorphine. Guidelines addressing pain management during cancer treatment are assessed to identify buprenorphine's place in therapy. Recent literature reporting efficacy and safety of buprenorphine use in pain management during cancer treatment will be presented. EXPERT OPINION: Current literature shows strong data for transdermal buprenorphine and promising data for sublingual buprenorphine. With this evidence, buprenorphine could have a more expanded role in managing adult cancer pain.

[Transdermal buprenorphine for acute postoperative pain: a systematic review]. / Uso da buprenorfina transdérmica na dor aguda pós­operatória: revisão sistemática.

BACKGROUND AND OBJECTIVES: Postoperative pain is still a major concern in several surgical procedures. Multimodal analgesia is best for postoperative pain management; however, opioid therapy is still the main treatment for pain after surgical procedures. Transdermal buprenorphine is a partial µ agonist opioid widely used for chronic pain syndromes, with limited evidence for acute postoperative pain. A systematic review of studies examining transdermal buprenorphine for acute pain management after surgery was conducted. CONTENTS: Data from PubMed, Embase, The Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL via EBSCOhost, and LILACS were reviewed, including randomized clinical trials that evaluated total postoperative pain, postoperative analgesic consumption, drug-related side effects and patient satisfaction with analgesia regimen. Data from nine studies (615 patients) were included in this review. Most studies initiated transdermal buprenorphine use 6 to 48 hours before surgery, maintaining use from 1 to 8 days after the procedure. Most studies showed lower or similar postoperative pain scores, postoperative analgesic consumption and patient satisfaction comparing buprenorphine to placebo, tramadol, celecoxib, flurbiprofen and parecoxib. The incidence of side effects varied between studies, with most showing no increase in drug-related side effects with buprenorphine use, except one study, which compared buprenorphine to oral tramadol, and one to transdermal fentanyl. However, most results were derived from evidence with an overall high or unclear risk of bias. CONCLUSIONS: Although more studies are necessary, initial results show that transdermal buprenorphine seems to be an effective and safe opioid choice for management of acute postoperative pain.

Deprescribing Opioids in Chronic Non-cancer Pain: Systematic Review of Randomised Trials.

BACKGROUND: Deprescribing, the process of reducing or discontinuing unnecessary or harmful medicines is an essential part of clinical practice. OBJECTIVE: To evaluate the efficacy of interventions designed to deprescribe opioid analgesics for pain relief in patients with chronic non-cancer pain. METHODS: We searched electronic databases, including clinical trial registries, from database inception to 13th January 2020 without restrictions, and conducted citation tracking. Our systematic review included randomised controlled trials (RCTs) evaluating interventions reducing the prescription, or use of opioid analgesics in patients with chronic pain versus control. Inventions could be aimed at the patient, clinician, or both. We excluded trials enrolling patients with cancer or illicit drug use. Two authors independently screened and extracted data. Outcome follow-up timepoints were short (≤ 3 months), intermediate (> 3 but < 12 months) or long (≥ 12 months) term. Primary outcome was the reduction in opioid dose [morphine milligram equivalent (MME) mg/day]. Methodological quality was assessed using the Cochrane Risk of Bias Tool. RESULTS: We included ten patient-focused RCT interventions (n = 835; median 37 participants) and 2 testing clinician-focused interventions (n = 291 clinicians); none at low risk of bias. Patient-focused interventions did not reduce opioid dose in the intermediate term [e.g. dose reduction protocol, mean difference (MD) - 19.9 MME, 95% CI - 107.5 to 67.7], nor did they increase the number of participants who ceased their dose, or increase the risk of serious adverse events or adverse events. One clinician intervention of education plus decision tools versus decision tools alone reduced the number of opioid prescriptions (risk difference (RD) - 0.1, 95% CI - 0.2 to - 0.1), dose (MD - 5.3 MME, 95% CI - 6.2 to - 4.5) and use (RD - 0.1, 95% CI - 0.1 to - 0.0) in the long term. LIMITATIONS: Study heterogeneity prevented meta-analysis. CONCLUSION: The small number of studies and heterogeneity prevented firm conclusions to recommend any one opioid-analgesic-deprescribing strategy in patients with chronic pain. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42017068422.

Transdermal buprenorphine for acute postoperative pain: a systematic review / Uso da buprenorfina transdérmica na dor aguda pós-operatória: revisão sistemática

Background and objectives: Postoperative pain is still a major concern in several surgical procedures. Multimodal analgesia is best for postoperative pain management; however, opioid therapy is still the main treatment for pain after surgical procedures. Transdermal buprenorphine is a partial µ-agonist opioid widely used for chronic pain syndromes, with limited evidence for acute postoperative pain. A systematic review of studies examining transdermal buprenorphine for acute pain management after surgery was conducted. Contents: Data from PubMed, Embase, The Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL via EBSCOhost, and LILACS were reviewed, including randomized clinical trials that evaluated total postoperative pain, postoperative analgesic consumption, drug-related side effects and patient satisfaction with analgesia regimen. Data from nine studies (615 patients) were included in this review. Most studies initiated transdermal buprenorphine use 6 to 48 hours before surgery, maintaining use from 1 to 28 days after the procedure. Most studies showed lower or similar postoperative pain scores, postoperative analgesic consumption and patient satisfaction comparing buprenorphine to placebo, tramadol, celecoxib, flurbiprofen and parecoxib. The incidence of side effects varied between studies, with most showing no increase in drug-related side effects with buprenorphine use, except one study, which compared buprenorphine to oral tramadol, and one to transdermal fentanyl. However, most results were derived from evidence with an overall high or unclear risk of bias. Conclusions: Although more studies are necessary, initial results show that transdermal buprenorphine seems to be an effective and safe opioid choice for management of acute postoperative pain

Justificativa e objetivos: A dor pós-operatória ainda é uma queixa importante em vários procedimentos cirúrgicos. A analgesia multimodal é a melhor conduta para a dor pós-operatória, embora a terapia com opioides ainda seja o principal tratamento para a dor após procedimentos cirúrgicos. A buprenorfina transdérmica é um opioide agonista µ amplamente prescrito nas síndromes de dor crônica, mas com limitada evidência do seu uso para dor aguda no pós-operatório. Realizamos revisão sistemática de estudos que examinaram o papel da buprenorfina transdérmica no tratamento da dor aguda pós-operatória. Conteúdo: Revisamos os dados de PubMed, Embase, Registro Central de Ensaios Controlados Cochrane (CENTRAL), CINAHL via EBSCOhost e LILACS, incluindo estudos clínicos randomizados que avaliaram a dor pós-operatória total, consumo de analgésicos pós-operatórios, efeitos colaterais relacionados a medicamentos e satisfação do paciente com esquema de analgesia. Dados de nove estudos (615 pacientes) foram incluídos nesta revisão. A maioria dos estudos iniciou o uso transdérmico de buprenorfina 6 a 48 horas antes da cirurgia, mantendo o uso de 1 a 28 dias após o procedimento. A maioria dos estudos encontrou valores semelhantes ou menores para o escore de dor pós-operatória, consumo pós-operatório de analgésicos e satisfação do paciente quando a buprenorfina foi comparada ao placebo, tramadol, celecoxibe, flurbiprofeno e parecoxibe. A incidência de efeitos colaterais oscilou nos estudos, e a maioria não mostrou aumento de efeito colateral relacionado ao uso de buprenorfina, exceto em dois estudos, um que comparou buprenorfina ao tramadol oral e outro ao fentanil transdérmico. No entanto, a maioria dos resultados foi obtida a partir de evidências com um risco geral alto ou risco de viés impreciso. Conclusões: Embora sejam necessários mais estudos, os resultados iniciais mostram que a buprenorfina transdérmica parece ser uma forma de administração segura e efetiva de opioide no tratamento da dor aguda pós-operatória

Comparison of buprenorphine and methadone in the management of maternal opioid use disorder in full term pregnancies.

Objectives To compare pregnancy outcomes with medication assisted treatment using. methadone or buprenorphine in term mothers with opioid use disorder. Methods A cohort of women receiving medication assisted treatment with either methadone or buprenorphine were identified from delivery records over a 10-year period. Women were excluded with delivery <37 weeks, multiple gestations, or a known anomalous fetus. Maternal demographics, medications, mode of delivery, birthweight, newborn length of stay, and neonatal abstinence syndrome were extracted. The study was IRB approved and a p-value of <0.05 was significant. Results There were 260 women, 140 (53.8%) with methadone use and 120 (46.2%) with buprenorphine use. Groups were similar for maternal age, race, parity, homeless rate, tobacco use, mode of delivery and incidence of neonatal abstinence syndrome. The methadone group had a lower mean newborn birthweight (2874±459 g) and a greater incidence of low birth weight (11.4%) than the buprenorphine group (3282±452 g; p<0.001 and 2.5%; p=0.006). The incidence of neonatal abstinence syndrome was similar between groups (97% methadone vs. 92.5% buprenorphine; p=0.08). The methadone group had a longer newborn length of stay (11.4+7.4 days) and more newborn treatment with morphine (44.6%) than the buprenorphine group (8.2+4.4 days; p<0.001 and 24.2%; p<0.001). Maternal methadone use was an independent predictor for a newborn length of hospital stay >7 days (OR 3.61; 95% confidence interval 1.32-9.86; p=0.01). Conclusions Medication assisted treatment favors buprenorphine use when compared to. methadone with an increased birthweight, reduced need for newborn treatment, and a shorter newborn length of stay in term infants.

Scalable in silico Simulation of Transdermal Drug Permeability: Application of BIOiSIM Platform.

INTRODUCTION: Transdermal drug delivery is gaining popularity as an alternative to traditional routes of administration. It can increase patient compliance because of its painless and noninvasive nature, aid compounds in bypassing presystemic metabolic effects, and reduce the likelihood of adverse effects through decreased systemic exposure. In silico physiological modeling is critical to predicting dermal exposure for a therapeutic and assessing the impact of different formulations on transdermal disposition. METHODS: The present study aimed at developing a physiologically based transdermal platform, "BIOiSIM", that could be globally applied to a wide variety of compounds to predict their transdermal disposition. The platform integrates a 16-compartment model of compound pharmacokinetics and was used to simulate and predict drug exposure of three chemically and biologically distinct drug-like compounds. Machine learning optimization was composed of two components: exhaustive search algorithm (coarse-tuning) and descent (fine-tuning) integrated with the platform used to quantitatively determine parameters influencing pharmacokinetics (eg permeability, kperm) of test compounds. RESULTS: The model successfully predicted drug exposure (AUC, Cmax and Tmax) following transdermal application of morphine, buprenorphine and nicotine in human subjects, mostly with less than two-fold absolute average fold error (AAFE). The model was further able to successfully characterize the relationship between observed systemic exposure and intended pharmacological effect. The predicted systemic concentration of morphine and plasma levels of endogenous pain biomarkers were used to estimate the effectiveness of a given therapeutic regimen. CONCLUSION: BIOiSIM marks a novel approach to in silico prediction that will enable leveraging of machine learning technology in the pharmaceutical space. The approach to model development outlined results in scalable, accurate models and enables the generation of large parameter/coefficient datasets from in vivo clinical data that can be used in future work to train quantitative structure activity relationship (QSAR) models for predicting likelihood of compound utility as a transdermally administered therapeutic.

A Comparison of Buprenorphine, Sustained release Buprenorphine, and High concentration Buprenorphine in Male New Zealand White Rabbits.

Pain management in rabbits can be difficult because they are adept at hiding pain and can be stressed by handling and restraint for injection. The use of opioid analgesics with prolonged durations of activity could alleviate pain, but associated adverse effects including gastrointestinal ileus, inappetence, and tissue reactions have been reported. In this study, we compared gross tissue reactions at the site of injection, food consumption, and fecal production after single injections of buprenorphine HCl (Bup; n = 7), sustained-release buprenorphine (BupSR; n = 8), and high-concentration buprenorphine (BupHC; n = 7) during the first 3 d after minor survival surgery. We also measured plasma concentrations of the parent drug, buprenorphine, and 3 metabolites (buprenorphine-3-glucuronide (B3G), norbuprenorphine-3ß-glucuronide (N3G), and norbuprenorphine (NB)). Plasma levels of buprenorphine remained above the theoretical minimal analgesic concentration for 4 h for Bup and 42 h for BupHC. For BupSR, plasma levels of buprenorphine remained above the theoretical minimal analgesic concentration for approximately 77 h, starting 15 h after administration. For all 3 formulations, N3G was the most prominent metabolite in the blood. No injection site reactions were visible grossly in any rabbit. Relative to baseline measures and compared with controls (n = 8), food consumption was suppressed on days 1 through 3 in rabbits that received BupSR and on days 2 through 3 in those given BupHC. Feces production on day 3 was reduced to a greater extent in BupSR rabbits than control animals. Two rabbits in the BupHC group exhibited neurologic signs after drug administration. These adverse effects should be considered when choosing a long-lasting buprenorphine formulation to manage pain in rabbits.

Analgesic impact of buprenorphine transdermal patch in total hip arthroplasty: A randomized controlled trial protocol.

BACKGROUND: The efficacy and safety of buprenorphine transdermal patch (BTP) has been well established in chronic pain, but data regarding acute postoperative pain relief is still very limited. Therefore, we design a prospective, randomized, controlled study to evaluate the effectiveness and safety of the BTP for postoperative analgesia in total hip arthroplasty. METHODS: This study is designed as a single-center, prospective, double-blind, randomized controlled trial. Group A receives a 10 mg patch of buprenorphine at the conclusion of surgery which is continued for 14 days. Group B receives a conventional analgesic regimen, that is, IV paracetamol 1 mg every 8 hours alternating with parenteral tramadol 50 mg every 8 hours for the first 2 postoperative days followed by oral administration of the same drug still the end of 2 weeks. A total of 160 patients are needed with an allowance for 10% drop-out. The primary outcome of this noninferiority study is opioid consumption within the first 24 hours following surgery. The secondary outcomes included numerical rating scale scores at rest, postoperative complications, length of hospital stay, and patient satisfaction. RESULTS: This trial is expected to be the largest randomized trial assessing the efficacy of BTP after primary total hip arthroplasty and powered to detect a potential difference in the primary outcome. TRIAL REGISTRATION NUMBER: This study protocol was registered in Research Registry (researchregistry5524).

Recommendations for Managing Opioid-Tolerant Surgical Patients within Enhanced Recovery Pathways.

PURPOSE OF REVIEW: One of the consequences of the opioid epidemic is an increase in the number of opioid-tolerant patients. These patients are at higher risk for readmission and longer hospital stays following surgery. Enhanced recovery after surgery (ERAS) pathways can be used as a framework for providing high-quality comprehensive care to patient population. It is estimated that as many as 15% of all surgery patients in the USA are receiving opioids going into surgery. The number of patients on medication maintenance therapy with long-acting opioids such as methadone or partial mu receptor agonists like buprenorphine is rising, which poses a challenge for perioperative healthcare providers. RECENT FINDINGS: Preoperative opioid tolerance is an independent predictor for increased length of hospital stays, high costs, and increased readmission rates following surgery. Given the recent trends, it is likely that more opioid-tolerant patients will require surgery in near future. Enhanced recovery programs can be used to provide a framework for high-quality care to opioid-tolerant patients throughout all phases of the perioperative process. To improve the quality of care of opioid-tolerant patients, we present five general recommendations for clinicians to consider and possibly incorporate into ERAS programs and care protocols. Recommendations include the following: opioid-tolerant patients should not be excluded from ERAS programs; opioid-tolerant patients should be identified preoperatively; programs should establish standard practices for patients on medication maintenance therapy and buprenorphine; opioid-tolerant patients should receive multimodal analgesia perioperatively; and opioid-tolerant patients should receive coordinated follow up after surgery.