Snakebites in Cameroon: Tolerance of a Snake Antivenom (Inoserp™ PAN-AFRICA) in Africa in Real-Life Conditions.

Snakebite envenomation (SBE) is a public health issue in sub-Saharan countries. Antivenom is the only etiological treatment. Excellent tolerance is essential in managing SBE successfully. This study aimed to evaluate tolerance of InoserpTM PAN-AFRICA (IPA). It was conducted on fourteen sites across Cameroon. IPA was administered intravenously and repeated at the same dose every two hours if needed. Early and late tolerance was assessed by the onset of clinical signs within two hours and at a visit two weeks or more after the first IPA administration, respectively. Over 20 months, 447 patients presenting with a snakebite were included. One dose of IPA was administered to 361 patients and repeated at least once in 106 patients. No significant difference was shown between the proportion of adverse events in patients who received IPA (266/361, 73.7%) and those who did not (69/85, 81.2%) (p = 0.95). Adverse reactions, probably attributable to IPA, were identified in four (1.1%) patients, including one severe (angioedema) and three mild. All these reactions resolved favorably. None of the serious adverse events observed in twelve patients were attributed to IPA. No signs of late intolerance were observed in 302 patients. Tolerance appears to be satisfactory. The availability of effective and well-tolerated antivenoms would reduce the duration of treatment and prevent most disabilities and/or deaths.

Mesenchymal Stem Cells Increase Drug Tolerance of A431 Cells Only in 3D Spheroids, Not in 2D Co-Cultures.

Mesenchymal stem cells (MSCs) are an integral part of the tumor microenvironment (TME); however, their role is somewhat controversial: conflicting reports suggest that, depending on the stage of tumor development, MSCs can either support or suppress tumor growth and spread. Additionally, the influence of MSCs on drug resistance is also ambiguous. Previously, we showed that, despite MSCs proliferating significantly more slowly than cancer cells, there are chemotherapeutic drugs which proved to be similarly toxic to both cell types. Here we established 2D co-cultures and 3D co-culture spheroids from different ratios of GFP-expressing, adipose tissue-derived MSCs and A431 epidermoid carcinoma cells tagged with mCherry to investigate the effect of MSCs on cancer cell growth, survival, and drug sensitivity. We examined the cytokine secretion profile of mono- and co-cultures, explored the inner structure of the spheroids, applied MSC-(nutlin-3) and cancer cell-targeting (cisplatin) treatments separately, monitored the response with live-cell imaging and identified a new, double-fluorescent cell type emerging from these cultures. In 2D co-cultures, no effect on proliferation or drug sensitivity was observed, regardless of the changes in cytokine secretion induced by the co-culture. Conversely, 3D spheroids developed a unique internal structure consisting of MSCs, which significantly improved cancer cell survival and resilience to treatment, suggesting that physical proximity and cell-cell connections are required for MSCs to considerably affect nearby cancer cells. Our results shed light on MSC-cancer cell interactions and could help design new, better treatment options for tumors.

Natural History of Opioid Use in Naive and Tolerant Patients in Revision Total Hip Arthroplasty.

BACKGROUND: Opioid use after revision total hip arthroplasty (rTHA) has not been well characterized. The purpose of this study was to characterize preoperative, perioperative, and postoperative opioid use during rTHA. METHODS: Patients undergoing revision THA from 2010 to 2018 were screened for opioid use 3 months before revision surgery and tracked 24 months postoperatively. Patients were categorized as naïve or tolerant. Opioid prescriptions and average morphine milligram equivalents (MME) were compared between the two groups. RESULTS: One hundred twenty-four of 247 patients (50%) in the tolerant group averaged a preoperative MME of 23.7 mg/day. Postoperatively, tolerant patients received significantly higher daily MME at all time points, including at 3 months 31.4 versus 18.1 mg/day (P < 0.001), 6 months 19.9 versus 2.95 mg/day (P < 0.001), 12 months 14.3 versus 3.5 mg/day (P < 0.001), and 24 months 10.7 versus 2.17 mg/day (P < 0.001). Tolerant patients were more likely to have a prescription at 6 months (44% versus 22%), 12 months (41.4% versus 24%), and 24 months (38% versus 19.3%) (P < 0.001, P = 0.002, P < 0.001, respectively). DISCUSSION: Opioid-tolerant patients had higher postoperative MME requirements for longer recovery duration. Both groups reduced opioid use at 3 months and plateaued at 6 months. These findings can help the revision surgeon counsel patients and expectations.

Motivation and context of concurrent stimulant and opioid use among persons who use drugs in the rural United States: a multi-site qualitative inquiry.

BACKGROUND: In recent years, stimulant use has increased among persons who use opioids in the rural U.S., leading to high rates of overdose and death. We sought to understand motivations and contexts for stimulant use among persons who use opioids in a large, geographically diverse sample of persons who use drugs (PWUD) in the rural settings. METHODS: We conducted semi-structured individual interviews with PWUD at 8 U.S. sites spanning 10 states and 65 counties. Content areas included general substance use, injection drug use, changes in drug use, and harm reduction practices. We used an iterative open-coding process to comprehensively itemize and categorize content shared by participants related to concurrent use. RESULTS: We interviewed 349 PWUD (64% male, mean age 36). Of those discussing current use of stimulants in the context of opioid use (n = 137, 39%), the stimulant most used was methamphetamine (78%) followed by cocaine/crack (26%). Motivations for co-use included: 1) change in drug markets and cost considerations; 2) recreational goals, e.g., seeking stronger effects after heightened opioid tolerance; 3) practical goals, such as a desire to balance or alleviate the effects of the other drug, including the use of stimulants to avoid/reverse opioid overdose, and/or control symptoms of opioid withdrawal; and 4) functional goals, such as being simultaneously energized and pain-free in order to remain productive for employment. CONCLUSION: In a rural U.S. cohort of PWUD, use of both stimulants and opioids was highly prevalent. Reasons for dual use found in the rural context compared to urban studies included changes in drug availability, functional/productivity goals, and the use of methamphetamine to offset opioid overdose. Education efforts and harm reduction services and treatment, such as access to naloxone, fentanyl test strips, and accessible drug treatment for combined opioid and stimulant use, are urgently needed in the rural U.S. to reduce overdose and other adverse outcomes.

Intravenous administration of recombinant Phα1ß: Antinociceptive properties and morphine tolerance reversal in a cancer-associated pain model.

Cancer-related pain is considered one of the most prevalent symptoms for those affected by cancer, significantly influencing quality of life and treatment outcomes. Morphine is currently employed for analgesic treatment in this case, however, chronic use of this opioid is limited by the development of analgesic tolerance and adverse effects, such as digestive and neurological disorders. Alternative therapies, such as ion channel blockade, are explored. The toxin Phα1ß has demonstrated efficacy in blocking calcium channels, making it a potential candidate for alleviating cancer-related pain. This study aims to assess the antinociceptive effects resulting from intravenous administration of the recombinant form of Phα1ß (r-Phα1ß) in an experimental model of cancer-related pain in mice, tolerant or not to morphine. The model of cancer-induced pain was used to evaluate these effects, with the injection of B16F10 cells, followed by the administration of the r-Phα1ß, and evaluation of the mechanical threshold by the von Frey test. Also, adverse effects were assessed using a score scale, the rotarod, and open field tests. Results indicate that the administration of r-Phα1ß provoked antinociception in animals with cancer-induced mechanical hyperalgesia, with or without morphine tolerance. Previous administration of r-Phα1ß was able to recover the analgesic activity of morphine in animals tolerant to this opioid. r-Phα1ß was proved safe for these parameters, as no adverse effects related to motor and behavioral activity were observed following intravenous administration. This study suggests that the concomitant use of morphine and r-Phα1ß could be a viable strategy for pain modulation in cancer patients.

Pharmacological agents targeting drug-tolerant persister cells in cancer.

Current cancer therapy can be effective, but the development of drug resistant disease is the usual outcome. These drugs can eliminate most of the tumor burden but often fail to eliminate the rare, "Drug Tolerant Persister" (DTP) cell subpopulations in residual tumors, which can be referred to as "Persister" cells. Therefore, novel therapeutic agents specifically targeting or preventing the development of drug-resistant tumors mediated by the remaining persister cells subpopulations are needed. Since approximately ninety percent of cancer-related deaths occur because of the eventual development of drug resistance, identifying, and dissecting the biology of the persister cells is essential for the creation of drugs to target them. While there remains uncertainty surrounding all the markers identifying DTP cells in the literature, this review summarizes the drugs and therapeutic approaches that are available to target the persister cell subpopulations expressing the cellular markers ATP-binding cassette sub-family B member 5 (ABCB5), CD133, CD271, Lysine-specific histone demethylase 5 (KDM5), and aldehyde dehydrogenase (ALDH). Persister cells expressing these markers were selected as the focus of this review because they have been found on cells surviving following drug treatments that promote recurrent drug resistant cancer and are associated with stem cell-like properties, including self-renewal, differentiation, and resistance to therapy. The limitations and obstacles facing the development of agents targeting these DTP cell subpopulations are detailed, with discussion of potential solutions and current research areas needing further exploration.

Development of opioid analgesic tolerance in rat to extended-release buprenorphine formulated for laboratory subjects.

Buprenorphine in an extended-release formulation intended for use in laboratory subjects is frequently administered to rats to provide extended analgesia without repeated handling. While levels of buprenorphine may persist in serum once extended-release buprenorphine has been introduced, exposure to opioids can cause opioid tolerance or opioid-induced hypersensitivity. This work examined the analgesic duration and efficacy of a single administration of extended-release buprenorphine intended for use in laboratory subjects in models of inflammatory pain and post-operative pain and the development of opioid tolerance in rat. After subcutaneous administration of 1 mg/kg extended-release buprenorphine, analgesic efficacy did not persist for the expected 72 hours. No changes were observed in mechanical thresholds in the hindpaws that were contralateral to the injury, suggesting a lack of centrally mediated opioid-induced hypersensitivity. To determine whether opioid tolerance arose acutely after one exposure to extended-release buprenorphine, we conducted the warm water tail flick assay; on Day 1 we administered either saline or extended-release buprenorphine (1 mg/kg) and on Day 3 we quantified the standard buprenorphine dose-response curve (0.1-3 mg/kg). Rats previously given extended-release buprenorphine displayed decreased analgesic responses after administration of standard buprenorphine as compared to the robust efficacy of standard buprenorphine in control subjects. Males appeared to show evidence of acute opioid tolerance, while females previously exposed to opioid did not demonstrate a decreased response at the doses examined. Taken together, these results suggest that opioid tolerance arises quickly in male rats after exposure to the extended-release formulation of buprenorphine. This tolerance may account for the brief period of antinociception observed.

Evaluation of basal rate infusion in intravenous patient-controlled analgesia for post-cesarean section pain management: A randomized pilot study.

OBJECTIVE: Administering opioids via intravenous patient-controlled analgesia is a prevalent approach for managing postoperative pain. Nevertheless, due to concerns about opioid-related side effects and the potential for opioid tolerance, there is a growing emphasis on adopting opioid-sparing techniques for postoperative pain management. We aimed to investigate the effect of adding a basal rate infusion in fentanyl-based IVA following a cesarean section (CS). METHOD: Forty-eight patients, who received pain management through IVA after CS, were assigned randomly into 3 groups based on the background rate setting: Group 0 (0 mcg/hour, n = 16), Group 1 (15 mcg/hour, n = 16), and Group 2 (30 mcg/hour, n = 16). We assessed the impact of the basal infusion rate on opioid consumption and the visual analog scale (VAS) scores during the first 48 hours post-CS and also investigated opioid-induced side effects and the requirement for rescue analgesics in the ward during the first 48 hours after CS. RESULTS: In the initial 24 hours following CS, fentanyl consumption significantly increased in Group 2 compared with Group 0 and Group 1 (P = .037). At 24 hours, VAS scores both at rest and during movement, tended to decrease, as the basal rate increased; however, no significant differences were observed between the groups (P = .218 and 0.827, respectively). Between the first 24- and 48-hours post-CS, fentanyl consumption showed a marked increase in both Group 1 and Group 2 compared to Group 0 (P < .001). At 48 hours, the VAS scores at rest displayed a trend toward reduction; however, no significant differences between groups were evident (P = .165). Although the incidence of opioid-induced complications was noted, no statistically significant differences were recorded between groups during the initial 24 hours and subsequent 24 to 48 hours period (P = .556 and P = .345, respectively). CONCLUSION: The inclusion of a basal fentanyl infusion in the IVA protocol did not provide any advantages over an IVA devoid of a basal rate infusion in managing acute pain following CS.

The Devil's in the Depot Details: Case of Iatrogenic Opioid Intoxication After Buprenorphine Injection Requiring Surgical Excision.

ABSTRACT: Monthly long-acting injectable buprenorphine (LAI-BUP) is a treatment option for moderate to severe opioid use disorder. Safe administration of LAI-BUP requires preexisting opioid tolerance to prevent sedation and respiratory depression. In the event of adverse medication effects including oversedation, LAI-BUP can be surgically excised up to 14 days after administration ( https://www.sublocadehcp.com/dosing-administration ). However, the manufacturer does not provide guidance on the proper procedure for excision, and no case reports have been published documenting this procedure. We report a case of a man with methamphetamine use disorder and multiple unintentional fentanyl overdoses who inadvertently received LAI-BUP for overdose protection. This resulted in significant sedation for days, ultimately necessitating excision 5 days after administration. His sedation improved moderately at 24 hours after excision and significantly by 36 hours after excision. Providers seeking to use LAI-BUP to prevent overdose among those with unintentional opioid exposure must ensure sublingual buprenorphine tolerance before injection to avoid iatrogenic harm. Although manufacturer instructions mention that LAI-BUP can be excised under local anesthesia within 14 days of insertion, ideal excision is best performed in a setting with surgical instruments and cautery-such as the operating room-as the depot can adhere strongly to the surrounding subcutaneous tissue.

Strategies for treating acute pain in patients with opioid dependence: a scoping review protocol.

INTRODUCTION: People who are dependent on opioids experience acute pain similar to other individuals. However, treating acute pain in these patients renders unique challenges such as opioid-induced hyperalgesia, opioid tolerance, withdrawal and stigma from healthcare providers. Thus, it is crucial to identify effective strategies for treating acute pain in this population and to highlight gaps in knowledge to create a high standard of care. The main objective of the proposed scoping review is to identify current strategies for treating the acute pain in individuals with opioid dependence or use disorder. METHODS AND ANALYSIS: MEDLINE via the PubMed interface, Embase and Cochrane Central, Web of Science: Conference Proceedings Citation Index and Google Scholar will be searched. Forward and backward citation searching of the final included studies will also be conducted. Two independent reviewers will screen the titles and abstracts of sources, review and assess relevant full-text studies and extract data. Data will be presented in a diagram and will contribute to a qualitative thematic analysis. ETHICS AND DISSEMINATION: Data will be gathered from publicly accessible sources, so ethics approval is not necessary. The results will be disseminated through a peer-reviewed journal and reported at conferences related to addiction medicine. TRIAL REGISTRATION NUMBER: 10.17605/OSF.IO/BG6SJ.

Antibiotic resistance and tolerance: What can drug delivery do against this global threat?

Antimicrobial resistance and tolerance (AMR&T) are urgent global health concerns, with alarmingly increasing numbers of antimicrobial drugs failing and a corresponding rise in related deaths. Several reasons for this situation can be cited, such as the misuse of traditional antibiotics, the massive use of sanitizing measures, and the overuse of antibiotics in agriculture, fisheries, and cattle. AMR&T management requires a multifaceted approach involving various strategies at different levels, such as increasing the patient's awareness of the situation and measures to reduce new resistances, reduction of current misuse or abuse, and improvement of selectivity of treatments. Also, the identification of new antibiotics, including small molecules and more complex approaches, is a key factor. Among these, novel DNA- or RNA-based approaches, the use of phages, or CRISPR technologies are some potent strategies under development. In this perspective article, emerging and experienced leaders in drug delivery discuss the most important biological barriers for drugs to reach infectious bacteria (bacterial bioavailability). They explore how overcoming these barriers is crucial for producing the desired effects and discuss the ways in which drug delivery systems can facilitate this process.

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.

Efficacy and safety of adamgammadex for reversing rocuronium-induced deep neuromuscular blockade: A multicenter, randomized, phase IIb study.

The rapid reversal of deep neuromuscular blockade (NMB) is important but remains challenging. This study aimed to evaluate the efficacy and safety of adamgammadex versus sugammadex in reversing deep rocuronium-induced NMB. This multicenter, randomized, phase IIb study included 80 patients aged 18-64 years, American Society of Anesthesiologists (ASA) grade 1-2, undergoing elective surgery under general anesthesia with rocuronium. Patients were randomized to the adamgammadex 7, 8, and 9 mg/kg group or the sugammadex 4 mg/kg group. The primary efficacy variable was the time to recovery of train-of-four ratio (TOFr) to 0.9. The secondary efficacy variables were the time to recovery of TOFr to 0.7, antagonistic success rate of the recovery of TOFr to 0.9 within 5 min, and incidence rate of recurarization within 30 min after drug administration. The explorative efficacy variable was the time to recovery of the corrected TOFr to 0.9 (actual/baseline TOF ratio). Adamgammadex 7, 8, and 9 mg/kg and sugammadex 4 mg/kg groups did not significantly differ in all efficacy variables. Importantly, adamgammadex 9 mg/kg permitted reversal within a geometric mean of 2.9 min. According to the safety profile, adamgammadex achieved good tolerance and low incidence of drug-related adverse events compared with the 4 mg/kg sugammadex. Adamgammadex 7, 8, and 9 mg/kg facilitated rapid reversal of deep rocuronium-induced NMB and had good tolerance and low incidence of drug-related adverse events. Therefore, adamgammadex is a potential and promising alternative to sugammadex.

Unlocking the enigma of phenotypic drug tolerance: Mechanisms and emerging therapeutic strategies.

In the ongoing battle against antimicrobial resistance, phenotypic drug tolerance poses a formidable challenge. This adaptive ability of microorganisms to withstand drug pressure without genetic alterations further complicating global healthcare challenges. Microbial populations employ an array of persistence mechanisms, including dormancy, biofilm formation, adaptation to intracellular environments, and the adoption of L-forms, to develop drug tolerance. Moreover, molecular mechanisms like toxin-antitoxin modules, oxidative stress responses, energy metabolism, and (p)ppGpp signaling contribute to this phenomenon. Understanding these persistence mechanisms is crucial for predicting drug efficacy, developing strategies for chronic bacterial infections, and exploring innovative therapies for refractory infections. In this comprehensive review, we dissect the intricacies of drug tolerance and persister formation, explore their role in acquired drug resistance, and highlight emerging therapeutic approaches to combat phenotypic drug tolerance. Furthermore, we outline the future landscape of interventions for persistent bacterial infections.

Efficacy and Tolerance of Thalidomide in Patients With Very Early Onset Inflammatory Bowel Disease.

BACKGROUND: Few drugs have been studied for patients with very early onset inflammatory bowel disease (VEOIBD). This study aimed to evaluate the efficacy and tolerance of thalidomide in children with VEOIBD compared with children with pediatric-onset IBD (pIBD). METHODS: A retrospective cohort study with a control group was conducted. Propensity score 1:1 matching was used to identify control subjects. The treatment persistence; the causes of drug withdrawal; the rate of clinical remission and mucosal healing at 1, 2, and 3 years; and adverse events (AEs) were evaluated in children with VEOIBD treated with thalidomide and compared with children with pIBD. RESULTS: Thirty-nine courses of treatment with thalidomide in VEOIBD and pIBD patients were compared. The treatment persistence at 1, 2, and 3 years was 68.2% (95% confidence interval [CI], 50.8%-80.6%), 57.0% (95% CI, 39.6%-71.1%), and 50.9% (95% CI, 33.7%-65.8%) for VEOIBD patients and 81.7% (95% CI, 65.3%-90.9%), 60.0% (95% CI, 41.7%-74.3%) and 33.0% (95% CI, 17.4%-49.5%) for pIBD patients, respectively (P = .12). A significantly higher proportion of VEOIBD patients discontinued therapy due to lack of efficacy (48.2% vs 17.2%; P = .03), while AEs were the main reason for discontinuation in pIBD patients. Clinical remission and mucosal healing rates did not significantly differ between VEOIBD and pIBD patients. A significatively lower number of VEOIBD patients experienced AEs compared with pIBD patients (14 [35.9%] vs 30 [76.9%]; P = .0005). CONCLUSIONS: Thalidomide is an effective and tolerated treatment in children with VEOIBD. Discontinuation due to lack of efficacy is more frequent, but AEs are less common than in children with pIBD.

Thalidomide is a valid therapeutic option in children with very early onset inflammatory bowel diseases unresponsive to conventional therapies. Discontinuation due to lack of efficacy is more frequent, but adverse events are less common than in children with pediatric-onset inflammatory bowel disease.

Opioid dose titration for cancer pain.

BACKGROUND: Opioid dose titration is a fundamental process of opioid therapy in cancer pain. AIMS: To assess data opioid dose titration. METHODS: The principal opioid dose titration methods, outcomes, and modalities of administration regarding the different opioid preparations were examined in different clinical contexts. RESULTS: Most studies suggested that opioid-naive patients should be started at doses of 15-30 mg/day of oral morphine equivalents. Opioid-tolerant patients may receive low or higher doses of oral morphine equivalents, depending on the level of opioid tolerance. Generally, dose increments of 30%-50% seem to be indicated to start dose titration. Some patients with severe excruciating cancer pain may present as an emergency requiring a rapid application of powerful analgesic strategies. The intravenous use of opioids may circumvent this problem providing a faster pain relief, due to the large availability and rapid achievement of effective plasma concentrations. DISCUSSION: Opioid dose titration is a delicate passage in patients with cancer pain. This approach may be different according to different clinical conditions. Opioid dose titration requires expertise to optimize cancer pain management while minimizing the development of adverse effects. CONCLUSION: While most approaches are meaningful and partially supported by existing literature, more studies are necessary to establish advantages and disadvantages in different clinical conditions. Optimization of opioid dose titration is of paramount importance. SIGNIFICANCE: This review provides the most recent insights on the different modalities of opioid dose titration in cancer pain management.

A Balancing Act: Learning from the Past to Build a Future-Focused Opioid Strategy.

The harmful side effects of opioid drugs such as respiratory depression, tolerance, dependence, and abuse potential have limited the therapeutic utility of opioids for their entire clinical history. However, no previous attempt to develop effective pain drugs that substantially ameliorate these effects has succeeded, and the current opioid epidemic affirms that they are a greater hindrance to the field of pain management than ever. Recent attempts at new opioid development have sought to reduce these side effects by minimizing engagement of the regulatory protein arrestin-3 at the mu-opioid receptor, but there is significant controversy around this approach. Here, we discuss the ongoing effort to develop safer opioids and its relevant historical context. We propose a new model that reconciles results previously assumed to be in direct conflict to explain how different signaling profiles at the mu-opioid receptor contribute to opioid tolerance and dependence. Our goal is for this framework to inform the search for a new generation of lower liability opioid analgesics.

Initiation and rapid titration of methadone and slow-release oral morphine (SROM) in an acute care, inpatient setting: a case series.

BACKGROUND: Methadone titration in an outpatient setting typically involves initiation with subtherapeutic doses with slow titration to mitigate the risks of respiratory depression and overdose. In pregnancy, and generally, subtherapeutic doses of methadone and slow titrations are associated with poorer outcomes in terms of treatment retention and ongoing illicit opioid use. We aim to describe rapid titration of OAT in an inpatient setting for pregnant injection opioid users with high opioid tolerance secondary to a fentanyl-based illicit drug supply. METHODS: Retrospective case series of patients admitted to a tertiary center with a primary indication of opioid withdrawal and treatment for severe opioid use disorder in pregnancy. RESULTS: Twelve women received rapid methadone titrations with or without slow-release oral morphine for opioid use disorder during a total of fifteen hospital admissions. All women included in the study were active fentanyl users (12/12). Methadone dosing was increased rapidly with no adverse events with a median dose at day 7 of 65 mg (IQR 60-70 mg) and median discharge dose of 85 mg (IQR 70-92.5 mg) during their admission for titration. Slow-release oral morphine was used in half of the titration admissions (8/15) with a median dose of 340 mg (IQR 187.5-425 mg) at discharge. The median length of admission was 12 days (IQR 9.5-15). CONCLUSIONS: A rapid titration of methadone was completed in an inpatient setting with or without slow-release oral morphine, without adverse events showing feasibility of this protocol for a pregnant population in an inpatient setting. Patients achieved therapeutic doses of methadone (and/or SROM) faster than outpatient counterparts with no known adverse events.