Extended-release versus oral buprenorphine as opioid maintenance treatment during pregnancy-maternal and neonatal outcomes.

OBJECTIVE: To get information on subcutaneous extended-release buprenorphine as opioid maintenance treatment during pregnancy, we compared it to orally administered buprenorphine and buprenorphine-naloxone treatments. We hypothesized that maternal and neonatal outcomes do not differ between the treatment groups. Study design In this population-based cohort study, 60 pregnant individuals receiving non-changed opioid maintenance treatment for opioid use disorder with a buprenorphine product from the time before conception to the time after delivery and their newborns were included. They were divided into three groups based on the pharmacotherapy with subcutaneous extended-release buprenorphine, sublingual buprenorphine, or buprenorphine-naloxone. Statistical analyses were conducted using Fischer's exact tests, ANOVA tests, and Kruskal-Wallis tests. All the statistical tests were two-tailed. RESULTS: The frequency of pregnancy or delivery complications did not significantly differ between the group receiving extended-release buprenorphine and the other groups. During pregnancy, 38 % of the women used illicit drugs concomitantly, with equal frequency in the extended-release buprenorphine group and the other groups. Of the neonates, 93 % were born full-term and 90 % got at least eight Apgar points in one minute age, without significant differences between the groups (p = 0.57). The need for pharmacotherapy for neonatal opioid withdrawal syndrome was the lowest in the extended-release buprenorphine group (25 %) and highest in the sublingual buprenorphine group (67 %). Still, the difference between the treatment groups did not reach statistical significance (p = 0.17). Among all neonates, the breastfed infants were less likely to receive pharmacotherapy for withdrawal symptoms than the formula-fed ones (p = 0.048). CONCLUSIONS: Extended-release buprenorphine with steady drug concentration seems to be a promising pharmacotherapy option during pregnancy for mothers. Maternal health during pregnancy may contribute to the well-being of newborns. Larger trials are urgently needed to confirm these results..

High-Dose Buprenorphine Initiation in the Management of Opioid Use Disorder in Pregnancy.

Buprenorphine is commonly used as a treatment for opioid use disorder (OUD). Transition to buprenorphine traditionally has been done using a low-dose initiation regimen due to concerns surrounding precipitated withdrawal. There are increasing data supporting use of a high-dose initiation regimen in the nonpregnant population. This retrospective case series describes six individuals with OUD who underwent high-dose buprenorphine initiation in pregnancy. There were no instances of sedation, respiratory depression, supplemental oxygen use, or death. All individuals were successfully transitioned to buprenorphine. These findings provide support for high-dose buprenorphine initiation in pregnancy, but future large studies are needed.

Neuraxial clonidine is not associated with lower post-cesarean opioid consumption or pain scores in parturients on chronic buprenorphine therapy: a retrospective cohort study.

PURPOSE: Adequate post-cesarean delivery analgesia can be difficult to achieve for women diagnosed with opioid use disorder receiving buprenorphine. We sought to determine if neuraxial clonidine administration is associated with decreased opioid consumption and pain scores following cesarean delivery in women receiving chronic buprenorphine therapy. METHODS: This was a retrospective cohort study at a tertiary care teaching hospital of women undergoing cesarean delivery with or without neuraxial clonidine administration while receiving chronic buprenorphine. The primary outcome was opioid consumption (in morphine milligram equivalents) 0-6 h following cesarean delivery. Secondary outcomes included opioid consumption 0-24 h post-cesarean, median postoperative pain scores 0-24 h, and rates of intraoperative anesthetic supplementation. Multivariable analysis evaluating the adjusted effects of neuraxial clonidine on outcomes was conducted using linear regression, proportional odds model, and logistic regression separately. RESULTS: 196 women met inclusion criteria, of which 145 (74%) received neuraxial clonidine while 51 (26%) did not. In univariate analysis, there was no significant difference in opioid consumption 0-6 h post-cesarean delivery between the clonidine (8 [IQR 0, 15]) and control (1 [IQR 0, 8]) groups (P = 0.14). After adjusting for potential confounders, there remained no significant association with neuraxial clonidine administration 0-6 h (Difference in means 2.77, 95% CI [- 0.89 to 6.44], P = 0.14) or 0-24 h (Difference in means 8.56, 95% CI [- 16.99 to 34.11], P = 0.51). CONCLUSION: In parturients receiving chronic buprenorphine therapy at the time of cesarean delivery, neuraxial clonidine administration was not associated with decreased postoperative opioid consumption, median pain scores, or the need for intraoperative supplementation.

Direct induction onto high-dose long-acting injectable buprenorphine: A case series.

INTRODUCTION: This case series reports on five patients with opioid use disorder (OUD) who were commenced directly onto high-dose long-acting injectable buprenorphine (LAIB). METHOD: A retrospective audit and manual review of the electronic medical record at cohealth Innerspace was conducted for patients who had been directly inducted onto high-dose LAIB. RESULTS: Five cases were identified on retrospective manual file review. All patients identified were males aged between 33 and 60 years old and were treated with either high-dose Buvidal Weekly and Monthly preparations. No immediate significant adverse effects were noticed and 4 out of 5 remain engaged with treatment. CONCLUSION: This case series shows it is possible to directly induct patients with OUD onto high-dose LAIB preparations without significant side effects or harm to the patient and could be considered a viable option in the treatment of patients with OUD.

Buprenorphine dispensing before and after the April 2021 X-Waiver exemptions: An interrupted time series analysis.

BACKGROUND: Until the end of 2022, a special registration, known as the X-waiver, was required to prescribe buprenorphine in the US. Before its removal, US federal regulations trialed an X-waiver exemption, initiated on April 28, 2021, which permitted buprenorphine prescribing for up to 30 patients without additional training. We aimed to understand if these regulatory changes impacted buprenorphine dispensing. METHODS: We conducted an interrupted time series analysis to understand changes in buprenorphine dispensing during the 26 weeks after the X-waiver exemption compared to the expected baseline trend established in the 26 weeks before using the IQVIA Longitudinal Prescription claims database. The primary outcome was number of new buprenorphine prescribers nationwide (defined as no prior buprenorphine prescription dispensed in the last 26 weeks). Segmented regression estimated relative changes in buprenorphine dispensing at 1, 13, and 26 weeks post-X-waiver change. RESULTS: A total of 15,517,525 prescriptions filled for 1,328,172 patients (43.4 % female) ordered by 62,312 providers were included for analysis. At 26 weeks post-X-waiver change, there was no change in the number of new prescribers compared to the expected baseline trend (-2.7 % [95 % CI:-8.3,2.9]). The number of new (15.2 % [4.6,25.8]) and existing (1.7 % [0.9,2.4]) patients and patients per prescriber (4.3 % [3,5.6]) increased. Buprenorphine prescriptions reimbursed by Medicaid increased (7.5 % [6.6,8.4]) while commercial fills decreased (-3.4 % [-5.3,-1.5]). CONCLUSIONS: The number of new prescribers did not increase six months post-X-waiver exemption while new patients continued to enter treatment at higher-than-expected rates. These findings suggest that additional interventions beyond the recent X-waiver removal may be needed to increase access to buprenorphine.

Effects of Midazolam/Dexmedetomidine with Buprenorphine or Extended-release Buprenorphine Anesthesia in C57BL/6 Mice.

The effects of commonly used injectable combinations of anesthetics such as ketamine and xylazine, with or without acepromazine, vary widely across individuals, have a shallow-dose response curve, and do not provide long-term analgesia. These drawbacks indicate the importance of continuing efforts to develop safe and effective injectable anesthetic combinations for mice. In this study, a series of experiments was designed to validate the use of dexmedetomidine and midazolam to provide chemical restraint for nonpainful procedures and the addition of buprenorphine or extended-release buprenorphine to reliably provide a surgical plane of anesthesia in C57BL/6J mice. Loss of consciousness was defined as the loss of the righting reflex (LORR); a surgical plane of anesthesia was defined as the LORR and loss of pedal withdrawal after application of a 300 g noxious stimulus to a hind paw. The combination of intraperitoneal 0.25 mg/kg dexmedetomidine and 6 mg/kg midazolam produced LORR, sufficient for nonpainful or noninvasive procedures, without achieving a surgical plane in 19 of 20 mice tested. With the addition of subcutaneous 0.1 mg/kg buprenorphine or 1 mg/kg buprenorphine-ER, 29 of 30 mice achieved a surgical plane of anesthesia. The safety and efficacy of the regimen was then tested by successfully performing a laparotomy in 6 mice. No deaths occurred in any trial, and, when administered 1 mg/kg atipamezole IP, all mice recovered their righting reflex within 11 min. The anesthetic regimen developed in this study is safe, is reversible, and includes analgesics that previous studies have shown provide analgesia beyond the immediate postsurgical period. Buprenorphine-ER can be safely substituted for buprenorphine for longer-lasting analgesia.

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.

Buprenorphine microdosing regimen using transdermal buprenorphine patches to transition from methadone to buprenorphine.

INTRODUCTION: This case series records a cohort of patients treated with transdermal buprenorphine patches as part of a buprenorphine microdose induction protocol to transition from methadone to buprenorphine in a community setting. This has historically been a difficult process to manage in community settings and this case series explored a method to gradually manage this in an outpatient setting. METHOD: A retrospective file audit was conducted of the electronic medical records of cohealth Innerspace patients who had undergone buprenorphine microdose induction using transdermal patches. A total of 32 patients were identified. RESULTS: In this case series 23 of the 32 patients successfully transitioned from methadone to sublingual or long-acting injectable depot buprenorphine preparations utilising the transdermal buprenorphine microdosing technique. All patients in this case series regardless of the success of the transition were retained in treatment. DISCUSSION AND CONCLUSIONS: A fixed-dose transdermal buprenorphine patch regimen enabled 23 of 32 patients in this case series transition from methadone to buprenorphine in an outpatient setting. Given the small sample size further research is required to demonstrate the effectiveness of this technique.

Tinkering with care: Implementing extended-release buprenorphine depot treatment for opioid dependence.

We examine how extended-release buprenorphine depot (BUP-XR) is put to use and made to work in implementation practices, attending to how care practices are challenged and adapted as a long-acting technology is introduced into service in opioid agonist treatment (OAT) in Australia. Our approach is informed by ideas in science and technology studies (STS) emphasising the irreducible entanglement of care practices and technology, and in particular the concept of 'tinkering' as a practice of adaptation. To make our analysis, we draw on qualitative interview accounts (n = 19) of service providers involved in BUP-XR implementation across five sites. Our analysis considers the disruptive novelty of BUP-XR. Tinkering to make a novel technology work in practice slows down the expectation of implementation in relation to transformative innovation, despite the promise of dramatic or rapid change. Tinkering allowed for more open relations, for new care practices that departed from the routine and familiar, opening potential for how BUP-XR could be put to use and made to work in its new situation, and as its situation evolved along-with its implementation. Flexibility and openness of altering relations was, however, at times, held in tension with inflexibility and closure. This analysis identifies a concern for what is made present and what is made absent in the altered care network affected by BUP-XR, with the multiple effects of supervised daily dosing practices thrown into relief as they become absented. Tinkering to implement BUP-XR locally connects with a broader assemblage of trial and movement in the constitution of treatment. The introduction of long-acting technologies prompts new questions about embedded implementation practices, including supervised dosing, urinalysis, the time and place of psychosocial support, and how other social aspects of care might be recalibrated in drug treatment.

Buprenorphine induced opioid withdrawal syndrome relieved by adjunctive Magnesium: A clinical trial.

INTRODUCTION: Precipitated opioid withdrawal syndrome (OWS) is a severe and intolerable situation that may occur by a pharmaceutical agent. Reactivation of inhibited N-methyl-d-aspartate (NMDA) receptor in person with prolonged opioid use can led to severe OWS. We conducted a double-blind, randomized clinical trial to assess the effect of magnesium sulfate (MGSO4) as an NMDA receptor antagonist on OWS. MATERIALS AND METHODS: The study randomly divided forty patients with precipitated OWS due to partial agonist (buprenorphine) use referred to the emergency unit of Toxicology Department of Mashhad University of Medical Sciences, Iran; into two groups. The control group received conventional therapies, including clonidine 0.1 mg tablet each hour, intravenous infusion of 10 mg diazepam every 30 min, and IV paracetamol (Acetaminophen) 1 g, while the intervention group received 3 g of MGSO4 in 20 min and then 10 mg/kg/h up to 2 h, in addition to the conventional treatment. The clinical opiate withdrawal scale (COWS) evaluated OWS at the start of the treatment, 30 min, and 2 h later. RESULTS: Both groups had similar demographic, opiate types, and COWS severity at the start of the intervention. COWS was lower in the intervention than the control group at 30 min (11.20 ± 2.86 and 14.65 ± 2.36, respectively, P = 0.002) and at 2 h (3.2 ± 1.61 and 11.25 ± 3.27, respectively, P < 0.001) after treatment. The intervention group received lesser doses of clonidine (0.12 ± 0.51 and 0.17 ± 0.45 mg, P = 0.003) and Diazepam (13.50 ± 5.87, 24.0 ± 6.80 mg, P = 0.001) than the control group. Serum magnesium levels raised from 1.71 ± 0.13 mmol/L to 2.73 ± 0.13 mmol/L in the intervention group. CONCLUSION: Magnesium can significantly reduce the severity of OWS. Additional studies are required to confirm these results.

Naloxone access in perinatal substance use disorder.

BACKGROUND: Risk of fatal drug overdose is higher in pregnant and postpartum people with substance use disorder (SUD) than for nonpregnant women of reproductive age. It is recommended that naloxone is prescribed for pregnancies complicated by opioid or stimulant use disorder. OBJECTIVE: The purpose of this study was to assess the rates of naloxone coprescribing with buprenorphine in a perinatal SUD (PSUD) specialty clinic and identify opportunities for pharmacist-led interventions to improve communication and documentation surrounding naloxone access to achieve a rate of 100% coprescribing of naloxone with buprenorphine. PRACTICE DESCRIPTION: A clinical pharmacist practitioner is embedded on the Project CARA (Care that Advocates Respect/Resilience/Recovery for All) team, which provides outpatient SUD care integrated with perinatal care in Western North Carolina. PRACTICE INNOVATION: The clinical pharmacist practitioner assessed baseline rates of naloxone coprescribing with medications for opioid use disorder. Interventions to improve rates of coprescribing include provider education, electronic health record (EHR) documentation templates, and direct patient outreach. EVALUATION METHODS: Baseline rates of naloxone coprescribing were assessed and then re-evaluated after different interventions to measure pharmacist impact. RESULTS: Each intervention improved rates of naloxone coprescribing in a PSUD clinic. EHR documentation templates had the largest impact on baseline efforts, although the long-term benefits derived from these efforts have not yet been demonstrated. Substantial time investment from the pharmacist was required to address patients' barriers to obtaining naloxone after their visits. CONCLUSION: Further process improvement should address barriers to naloxone access for both patients and providers. This may include proactive identification of patients in need of naloxone and a "meds-to-beds" pilot to assist patients in navigating logistical challenges.

Characterizing acute and postsurgical pain management in patients receiving buprenorphine or buprenorphine/naloxone.

BACKGROUND: There is currently a clinical dilemma in treating acute pain in patients receiving long-term buprenorphine products. METHODS: This is a retrospective cohort review involving patients receiving long-term buprenorphine therapy who either underwent a surgical procedure or presented to an emergency department (ED) for acute pain between January 1, 2012 and January 1, 2022. Patients were excluded if opioids were prescribed 30 days before the index date. Chart reviews were conducted to characterize buprenorphine treatment strategies and the addition of new pain medications. Chart review revealed (1) incidence of opioid use disorder (OUD) relapse, (2) hospital re-presentation for pain or OUD, (3) fatal and non-fatal overdose, and (4) all-cause mortality and suicidality. Descriptive statistics were used to analyze results. RESULTS: A total of 70 of 259 screened patients met inclusion criteria. The mean (±SD) age was 50.3 ± 13 years, 92.9% male, 64.3% White, and 78.6% had an OUD diagnosis. While 84.3% presented to the ED, 15.7% underwent surgical procedures. For the primary endpoint, the total daily dose of buprenorphine or buprenorphine/naloxone from index date to discharge was continued in 90.0%, increased in 2.9%, decreased in 1.4%, and discontinued in 5.7% of cases. At discharge, 46.2% were prescribed an additional pain medication. A total of 7.1% re-presented for pain or OUD relapse, 15.7% experienced an OUD relapse, 1.4% experienced new-onset suicidality, and 1.4% experience all-cause mortality within 90 days of the index date. No fatal or non-fatal opioid overdoses were observed. CONCLUSION: The most commonly observed practice was continuing buprenorphine doses in patients with acute or postsurgical pain, which was effective and safe. Although further data is necessary to fully elucidate these findings, the data herein may suggest that clinicians can safely continue buprenorphine doses in the acute pain setting in patients receiving these products chronically.

Pharmacokinetic-pharmacodynamic analysis of drug liking blockade by buprenorphine subcutaneous depot (CAM2038) in participants with opioid use disorder.

Buprenorphine is used to treat opioid use disorder (OUD). Weekly and monthly subcutaneous long-acting buprenorphine injections (CAM2038) provide more stable buprenorphine plasma levels and reduce the treatment burden, misuse, and diversion associated with sublingual transmucosal buprenorphine formulations. To characterize the pharmacokinetic/pharmacodynamic (PK/PD) relationship, a maximum inhibition (Imax) model was developed relating CAM2038 buprenorphine plasma concentration to drug liking maximum effect (Emax) visual analog scale (VAS; bipolar) score after intramuscular hydromorphone administration. Data included time-matched observations of buprenorphine plasma concentration and drug liking Emax VAS score after hydromorphone 18 mg administration in 47 non-treatment-seeking adults with moderate to severe OUD in a phase 2 study. Analysis used non-|linear mixed-effects modeling (NONMEM®). The final Imax model adequately described the PK/PD relationship between buprenorphine plasma concentration and drug liking Emax VAS score. Simulations showed drug liking was effectively blocked at low buprenorphine plasma concentrations (0.4 ng/mL) where the upper 95% confidence interval of the drug liking Emax VAS score was below the pre-defined 11-point complete blockade threshold. The buprenorphine plasma concentration required to achieve 90% of the maximal effect (IC90) of drug liking was 0.675 ng/mL. Interindividual variability in responses to buprenorphine was observed; some participants experienced fluctuating responses, and a few did not achieve drug liking blockade even with higher buprenorphine plasma concentrations. This affirms the need to individualize treatment and titrate doses for optimal treatment outcomes. PK/PD models were also developed for desire to use VAS and Clinical Opiate Withdrawal Scale (COWS) scores, with results aligned to those for drug liking.

Availability of Long-Acting Injectable Buprenorphine at Substance Use Treatment Facilities in 2021.

This study assesses the proportion of US substance use and mental health care facilities that offered any medications for opioid use disorder and, specifically, long-acting injectable buprenorphine in 2021.

Medications for opioid use disorder associated with reduced readmissions for patients with severe injection-related infections: A matched cohort study.

INTRODUCTION: Hospitalizations due to severe injection-related infections (SIRIs) and patient-directed discharge (PDD) in people who inject drugs (PWID) are increasing, but research on readmission outcomes at PDD is limited. In this retrospective, matched cohort study we evaluated predictors of 30-day readmission by discharge status among PWID. METHODS: Among patients diagnosed with SIRIs at a tertiary hospital, Fisher's exact tests assessed differences in readmission rates by discharge status. Medications for opioid use disorder (MOUD) at discharge was defined as either having a buprenorphine dose dispensed within 24 h of discharge and buprenorphine being included in the discharge summary as a prescription, or a methadone dose dispensed inpatient within 24 h of discharge. Logistic regression analyses evaluated predictors of readmission outcomes. RESULTS: Among 148 PWID with SIRI diagnosis, 30-day readmission rate following PDD was higher than standard discharge (25.7 % vs. 9.5 %, p = 0.016) and MOUD decreased odds of 30-day readmission (OR = 0.32, 95 % CI: 0.12,0.83, p = 0.012). >7 missed days of antibiotic treatment increased odds of 30-day readmission (OR 4.65, 95 % CI: 1.14, 31.72, p = 0.030) within PDD patients. CONCLUSIONS: PDD carries higher 30-day readmission rate compared to standard discharge. Strategies to reduce PDD rates and increase MOUD initiation may improve readmission outcomes.

Benzodiazepine Dose Intensity among Patients Concurrently Prescribed Buprenorphine in Rhode Island.

Background: The concomitant use of buprenorphine and benzodiazepines has been linked to patient fatalities, with greater risk occurring with higher doses of benzodiazepines. We assessed benzodiazepine dose intensity among patients who were concurrently prescribed buprenorphine, as compared with patients prescribed benzodiazepines who were not receiving buprenorphine. Methods: We conducted a cross-sectional analysis of adult patients who received at least a 30-day supply of benzodiazepines during 2018, using data from the Rhode Island (RI) Prescription Drug Monitoring Program. Mean daily diazepam milligram equivalents (DME) were calculated overall and according to patient sex, age group, payment type, and RI county. Multivariable logistic regression analyses were conducted to assess the odds of higher-dose benzodiazepine utilization among patients with concurrent use of buprenorphine, as compared with patients not prescribed buprenorphine, adjusting for patient demographics. Results: Compared to patients prescribed benzodiazepines who were not receiving buprenorphine, those with concurrent buprenorphine utilization had a significantly higher mean DME/day (19.22, 95% CI: 18.70-19.74; vs 10.94, 95% CI: 10.93-10.95; p < 0.001). Patients who were prescribed benzodiazepines with concurrent utilization of buprenorphine also had a comparatively higher odds of a DME/day ≥15 (aOR: 2.86, 95% CI: 2.63-3.10), ≥20 DME/day (aOR: 2.98, 95% CI: 2.75-3.24), and ≥25 DME/day (aOR: 2.99, 95% CI: 2.65-3.18). Conclusion: Compared to patients prescribed benzodiazepines for at least 30 days who were not receiving buprenorphine, patients concurrently utilizing benzodiazepines and buprenorphine had more than twice the odds of higher dose benzodiazepine utilization. Future studies are needed to assess the relationship between benzodiazepine dose intensity, overdose outcomes, and treatment retention among patients receiving buprenorphine.

A buprenorphine depot formulation provides effective sustained post-surgical analgesia for 72 h in mouse femoral fracture models.

Adequate pain management is essential for ethical and scientific reasons in animal experiments and should completely cover the period of expected pain without the need for frequent re-application. However, current depot formulations of Buprenorphine are only available in the USA and have limited duration of action. Recently, a new microparticulate Buprenorphine formulation (BUP-Depot) for sustained release has been developed as a potential future alternative to standard formulations available in Europe. Pharmacokinetics indicate a possible effectiveness for about 72 h. Here, we investigated whether the administration of the BUP-Depot ensures continuous and sufficient analgesia in two mouse fracture models (femoral osteotomy) and could, therefore, serve as a potent alternative to the application of Tramadol via the drinking water. Both protocols were examined for analgesic effectiveness, side effects on experimental readout, and effects on fracture healing outcomes in male and female C57BL/6N mice. The BUP-Depot provided effective analgesia for 72 h, comparable to the effectiveness of Tramadol in the drinking water. Fracture healing outcome was not different between analgesic regimes. The availability of a Buprenorphine depot formulation for rodents in Europe would be a beneficial addition for extended pain relief in mice, thereby increasing animal welfare.