Opioid analgesics for nociceptive cancer pain: A comprehensive review.

Pain is one of the most burdensome symptoms in people with cancer, and opioid analgesics are considered the mainstay of cancer pain management. For this review, the authors evaluated the efficacy and toxicities of opioid analgesics compared with placebo, other opioids, nonopioid analgesics, and nonpharmacologic treatments for background cancer pain (continuous and relatively constant pain present at rest), and breakthrough cancer pain (transient exacerbation of pain despite stable and adequately controlled background pain). They found a paucity of placebo-controlled trials for background cancer pain, although tapentadol or codeine may be more efficacious than placebo (moderate-certainty to low-certainty evidence). Nonsteroidal anti-inflammatory drugs including aspirin, piroxicam, diclofenac, ketorolac, and the antidepressant medicine imipramine, may be at least as efficacious as opioids for moderate-to-severe background cancer pain. For breakthrough cancer pain, oral transmucosal, buccal, sublingual, or intranasal fentanyl preparations were identified as more efficacious than placebo but were more commonly associated with toxicities, including constipation and nausea. Despite being recommended worldwide for the treatment of cancer pain, morphine was generally not superior to other opioids, nor did it have a more favorable toxicity profile. The interpretation of study results, however, was complicated by the heterogeneity in the study populations evaluated. Given the limited quality and quantity of research, there is a need to reappraise the clinical utility of opioids in people with cancer pain, particularly those who are not at the end of life, and to further explore the effects of opioids on immune system function and quality of life in these individuals.

Model-Informed Precision Dosing: Background, Requirements, Validation, Implementation, and Forward Trajectory of Individualizing Drug Therapy.

Model-informed precision dosing (MIPD) has become synonymous with modern approaches for individualizing drug therapy, in which the characteristics of each patient are considered as opposed to applying a one-size-fits-all alternative. This review provides a brief account of the current knowledge, practices, and opinions on MIPD while defining an achievable vision for MIPD in clinical care based on available evidence. We begin with a historical perspective on variability in dose requirements and then discuss technical aspects of MIPD, including the need for clinical decision support tools, practical validation, and implementation of MIPD in health care. We also discuss novel ways to characterize patient variability beyond the common perceptions of genetic control. Finally, we address current debates on MIPD from the perspectives of the new drug development, health economics, and drug regulations.

Opioid analgesia for acute low back pain and neck pain (the OPAL trial): a randomised placebo-controlled trial.

BACKGROUND: Opioid analgesics are commonly used for acute low back pain and neck pain, but supporting efficacy data are scarce. We aimed to investigate the efficacy and safety of a judicious short course of an opioid analgesic for acute low back pain and neck pain. METHODS: OPAL was a triple-blinded, placebo-controlled randomised trial that recruited adults (aged ≥18 years) presenting to one of 157 primary care or emergency department sites in Sydney, NSW, Australia, with 12 weeks or less of low back or neck pain (or both) of at least moderate pain severity. Participants were randomly assigned (1:1) using statistician-generated randomly permuted blocks to guideline-recommended care plus an opioid (oxycodone-naloxone, up to 20 mg oxycodone per day orally) or guideline-recommended care and an identical placebo, for up to 6 weeks. The primary outcome was pain severity at 6 weeks measured with the pain severity subscale of the Brief Pain Inventory (10-point scale), analysed in all eligible participants who provided at least one post-randomisation pain score, by use of a repeated measures linear mixed model. Safety was analysed in all randomly assigned eligible participants. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12615000775516). FINDINGS: Between Feb 29, 2016, and March 10, 2022, 347 participants were recruited (174 to the opioid group and 173 to the placebo group). 170 (49%) of 346 participants were female and 176 (51%) were male. 33 (19%) of 174 participants in the opioid group and 25 (15%) of 172 in the placebo group had discontinued from the trial by week 6, due to loss to follow-up and participant withdrawals. 151 participants in the opioid group and 159 in the placebo group were included in the primary analysis. Mean pain score at 6 weeks was 2·78 (SE 0·20) in the opioid group versus 2·25 (0·19) in the placebo group (adjusted mean difference 0·53, 95% CI -0·00 to 1·07, p=0·051). 61 (35%) of 174 participants in the opioid group reported at least one adverse event versus 51 (30%) of 172 in the placebo group (p=0·30), but more people in the opioid group reported opioid-related adverse events (eg, 13 [7·5%] of 174 participants in the opioid group reported constipation vs six [3·5%] of 173 in the placebo group). INTERPRETATION: Opioids should not be recommended for acute non-specific low back pain or neck pain given that we found no significant difference in pain severity compared with placebo. This finding calls for a change in the frequent use of opioids for these conditions. FUNDING: National Health and Medical Research Council, University of Sydney Faculty of Medicine and Health, and SafeWork SA.

Therapeutic drug monitoring of liposomal amphotericin B in children. Are we there yet? A systematic review.

INTRODUCTION: Therapeutic drug monitoring (TDM) is a tool that supports personalized dosing, but its role for liposomal amphotericin B (L-amb) is unclear. This systematic review assessed the evidence for L-amb TDM in children. OBJECTIVES: To evaluate the concentration-efficacy relationship, concentration-toxicity relationship and pharmacokinetic/pharmacodynamic (PK/PD) variability of L-amb in children. METHODS: We systematically reviewed PubMed and Embase databases following PRISMA guidelines. Eligible studies included L-amb PK/PD studies in children aged 0-18 years. Review articles, case series of 600 mg·h/L for nephrotoxicity. L-amb doses of 2.5-10 mg/kg/day were reported to achieve Cmax/MIC > 25 using an MIC of 1 mg/L. CONCLUSIONS: While significant PK variability was observed in children, evidence to support routine L-amb TDM was limited. Further studies on efficacy and toxicity benefits are required before routine TDM of L-amb can be recommended.

Outcomes from hematopoietic stem cell transplantation following treosulfan-based conditioning: A clinical and pharmacokinetic analysis.

BACKGROUND: The aims of this study are to report our experience with treosulfan-based conditioning regimens for patients with non-malignant hematologic conditions, correlating clinical outcomes at different time points post-transplant with treosulfan exposure (AUC). METHODS: This study was a single-center observational study investigating overall survival (OS), disease-free survival (DFS), and event-free survival (EFS) end-points post-transplant. The consequences of treosulfan AUC with respect to toxicity, correction of underlying disease, and long-term chimerism were also explored using pharmacokinetic analysis. RESULTS: Forty-six patients received 49 transplants with treosulfan and fludarabine-based conditioning between 2005 and 2023. Twenty-four patients also received thiotepa. Donor chimerism was assessed on either whole blood or sorted cell lines at different time points post-transplant. Thirty-nine patients received treosulfan pharmacokinetic assessment to evaluate cumulative AUC, with five infants receiving real-time assessment to facilitate daily dose adjustment. OS, DFS, and EFS were 87%, 81%, and 69%, respectively. Median follow-up was 32.1 months (range 0.82-160 months) following transplant. Lower EFS was associated with patient age (<1 year; p = .057) and lower cumulative treosulfan dose (<42 g/m2; p = .003). Stable donor chimerism in B-cell, NK-cell, and granulocyte lineages at 1-year post-transplant were more prevalent in patients receiving thiotepa conditioning. Two infants required daily dose adjustment to treosulfan to avoid high AUC. CONCLUSIONS: Excellent clinical outcomes and stable chimerism were observed in this patient series. The addition of thiotepa conferred no significant toxicity and trended toward sustained ongoing donor engraftment. Correlating treosulfan AUC with long-term patient outcomes is required.

Deprescribing interventions for gabapentinoids in adults: A scoping review.

The emerging issue of rising gabapentinoid misuse is being recognized alongside the lack of current evidence supporting the safe and effective deprescribing of gabapentinoids. This scoping review aimed to assess the extent and nature of gabapentinoid deprescribing interventions in adults, either in reducing dosages, or prescribing of, gabapentinoids. Electronic databases were searched on 23 February 2022 without restrictions. Eligible studies included randomized, non-randomized and observational studies that assessed an intervention aimed at reducing/ceasing the prescription/use of a gabapentinoid in adults for any indication in a clinical setting. The research outcomes investigated the type of intervention, prescribing rates, cessations, patient outcomes and adverse events. Extracted outcome data were categorized as either short (≤3 months), intermediate (>3 but <12 months) or long (≥12 months) term. A narrative synthesis was conducted. The four included studies were conducted in primary and acute care settings. Interventions were of dose-reducing protocols, education and/or pharmacological-based approaches. In the randomized trials, gabapentinoid use could be ceased in at least one third of participants. In the two observational trials, gabapentinoid prescribing rates decreased by 9%. Serious adverse events and adverse events specifically related to gabapentinoids were reported in one trial. No study included patient-focused psychological interventions in the deprescribing process, nor provided any long-term follow-up. This review highlights the lack of existing evidence in this area. Due to limited available data, our review was unable to make any firm judgements on the most effective gabapentinoid deprescribing interventions in adults, highlighting the need for more research in this area.

Evaluation of treosulfan cumulative exposure in paediatric patients through population pharmacokinetics and dosing simulations.

AIM: To investigate the pharmacokinetics (PK) of intravenous treosulfan in paediatric patients undergoing haematopoietic stem cell transplantation (HSCT) for a broad range of diseases and to explore the impact of different dosing regimens on treosulfan exposure (area under the concentration-time curve, AUC0→∞ ) through dosing simulations. METHODS: A prospective multicentre PK study was conducted using treosulfan concentration data (n = 423) collected from 53 children (median age 3.5, range 0.2-17.0 years) receiving three daily age-guided doses (10-14 g/m2 ). Population PK modelling was performed using NONMEM software, utilising a stepwise forward selection backward elimination method and likelihood-ratio test for screening covariates to describe PK variability. Monte Carlo simulation was used to generate patient PK data for 10 000 virtual paediatric patients and cumulative AUC0→∞ values were evaluated using age, body surface area (BSA) and model-based dosing regimens, targeting 4800 mg*h/L. RESULTS: Treosulfan concentration data were described using a one-compartment PK model with first-order elimination. Population mean (95% CI) estimates for clearance (CL) and volume of distribution (V) were 16.3 (14.9-18.1) L/h and 41.9 (38.8-45.1) L, respectively. Allometrically scaled body weight was the best covariate descriptor for CL and V, and maturational age further explained variability in CL. Dosing simulations indicated that in young patient groups (<2 years), a model-based dosing regimen more accurately achieved the target AUC0→∞ (58.3%) over the age (42.6%) and BSA-based (51.3%) regimens. CONCLUSION: Treosulfan disposition was described through allometric body weight and maturational age descriptors. Model-informed dosing is recommended for patients under 2 years. Treosulfan PK parameters and AUC0→∞ were not influenced by patient disease.

Towards Optimizing Hospitalized Older adults' MEdications (TO HOME): Multi-centre study of medication use and outcomes in routine care.

AIMS: Comprehensively investigate prescribing in usual care of hospitalized older people with respect to polypharmacy; potentially inappropriate medications (PIMs) according to Beers criteria; and cumulative anticholinergic and sedative medication exposure calculated with Drug Burden Index (DBI). Specifically, to quantify exposure to these measures on admission, changes between admission and discharge, associations with adverse outcomes and medication costs. METHODS: Established new retrospective inpatient cohort of 2000 adults aged ≥75 years, consecutively admitted to 6 hospitals in Sydney, Australia, with detailed information on medications, clinical characteristics and outcomes. Conducted cross-sectional analyses of index admission data from cohort. RESULTS: Cohort had mean (standard deviation) age 86.0 (5.8) years, 59% female, 21% from residential aged care. On admission, prevalence of polypharmacy was 77%, PIMs 34% and DBI > 0 in 53%. From admission to discharge, mean difference (95% confidence interval) in total number of medications increased 1.05 (0.92, 1.18); while prevalence of exposure to PIMs (-3.8% [-5.4, -2.1]) and mean DBI score (-0.02 [-0.04, -0.01]) decreased. PIMs and DBI score were associated with increased risks (adjusted odds ratio [95% confidence interval]) of falls (PIMs 1.63 [1.28, 2.08]; DBI score 1.21[1.00, 1.46]) and delirium (PIMs 1.76 [1.38, 1.46]; DBI score 1.42 [1.19, 1.71]). Each measure was associated with increased risk of adverse drug reactions (polypharmacy 1.42 [1.19, 1.71]; PIMs 1.87 [1.40, 2.49]; DBI score 1.90 [1.55, 2.15]). Cost (AU$/patient/hospital day) of medications contributing to PIMs and DBI was low ($0.29 and $0.88). CONCLUSION: In this large cohort of older inpatients, usual hospital care results in an increase in number of medications and small reductions in PIMs and DBI, with variable associations with adverse outcomes.

Dried Blood Spot Sampling in the Monitoring of Anticancer Therapy for Solid Tumors: A Systematic Review.

BACKGROUND: Dried blood spot (DBS) sampling is a convenient alternative to whole-blood sampling for therapeutic drug monitoring (TDM) in clinical practice. The aim of this study was to systematically review studies that have examined and used DBS sampling for the TDM of chemotherapy and targeted therapy agents for the treatment of patients with solid cancers. METHODS: Using the PRISMA guidelines, a systematic literature search of EMBASE and PUBMED was performed to identify eligible clinical studies that used DBS sampling to monitor chemotherapy or targeted therapy for the treatment of solid cancers. RESULTS: Of the 23 eligible studies, 3 measured concordance between drug concentrations determined by DBS and whole-blood, 7 developed analytical methods of DBS, and 13 performed both. DBS was employed for the TDM of everolimus (3 studies), vemurafenib (2 studies), pazopanib (2 studies), abiraterone (2 studies), mitotane, imatinib, adavosertib, capecitabine, 5-fluorouracil, gemcitabine, cyclophosphamide, ifosfamide, etoposide, irinotecan, docetaxel, gefitinib, palbociclib/ribociclib, and paclitaxel (one study each). The studies included a median of 14 participants (range: 6-34), with 10-50 µL of blood dispensed on DBS cards (20) and Mitra devices (3). Seventeen of the 20 studies that used DBS found no significant impact of the hematocrit on the accuracy and precision of the developed method in the normal hematocrit ranges (eg, 29.0%-59.0%). DBS and plasma or venous concentrations were highly correlated (correlation coefficient, 0.872-0.999) for all drugs, except mitotane, which did not meet a predefined level of significance (r > 0.872; correlation coefficient, r = 0.87, P < 0.0001). CONCLUSIONS: DBS provides an alternative sampling strategy for the TDM of many anticancer drugs. Further research is required to establish a standardized approach for sampling and processing DBS samples to allow future implementation.

Implementation of a peri-operative pain-management algorithm reduces the use of opioid analgesia following pelvic exenteration surgery.

AIM: This study aimed to investigate the implementation and pain-related outcomes of a peri-operative pain-management regimen for patients undergoing pelvic exenteration surgery at a university teaching hospital. METHOD: This is a single-site prospective observational cohort study involving 100 patients who underwent pelvic exenteration surgery between January 2017 and December 2018. A pain-management algorithm regarding the use of opioid-sparing multimodal analgesia was developed between the departments of anaesthesia, pain management and intensive care. The primary outcomes were: compliance with a pain-treatment algorithm compared with a similar retrospective surgical patient cohort in 2013-2014; and requirements for regular doses of opioid analgesia at discharge, measured in oral morphine equivalent daily dose (oMEDD). RESULTS: Following the introduction of a pain-management algorithm, regional anaesthesia techniques (spinal anaesthesia, transversus abdominus plane block, preperitoneal catheters or epidural analgesia) were used in 83/98 (84.7%) of the 2017-2018 cohort compared with 13/73 (17.8%) of the 2013-2014 cohort (p < 0.001). There was a reduction in the median dose of opioid analgesics (oMEDD) at time of discharge, from 150 mg (interquartile range [IQR]: 75.0-235.0 mg) in the 2013-2014 cohort to 10 mg (IQR: 0.00-45.0 mg) in the 2017-2018 cohort (p < 0.001). There was no change in pain intensity (assessed using the Verbal Numerical Rating Score) or oMEDD in the first 7 days following surgery. CONCLUSION: Since implementation of a novel peri-operative pain-treatment algorithm, the use of opioid-sparing regional techniques and preperitoneal catheters has increased. Additionally, the dose of opioids required at the time of discharge has reduced significantly.

Pain, pain management and related outcomes following pelvic exenteration surgery: a systematic review.

AIM: Pelvic exenteration surgery can improve survival in people with advanced colorectal cancer. This systematic review aimed to review pain intensity and other outcomes, for example the management of pain, the relationship between pain and the extent of surgery and the impact of pain on short-term outcomes. METHOD: Electronic databases were searched from inception to 1 May 2021. We included interventional studies of adults with any indication for pelvic exenteration surgery that also reported pain outcomes. Risk of bias was assessed using ROBINS-1. RESULTS: The search found 21 studies that reported pain following pelvic exenteration [n = 1317 patients, mean age 58.4 years (SD 4.8)]. Ten studies were judged to be at moderate risk of bias. Before pelvic exenteration, pain was reported by 19%-100% of patients. Five studies used validated measures of pain intensity. No study measured pain at all three time points in the surgical journey. The presence of pain before surgery predicted postoperative adverse pain outcomes, and pain is more likely to be experienced in those who require wider resections, including bone resection. CONCLUSION: Considering that pain following pelvic exenteration is commonly described by patients, the literature suggests that this symptom is not being measured and therefore addressed.

Deprescribing to optimise health outcomes for frail older people: a double-blind placebo-controlled randomised controlled trial-outcomes of the Opti-med study.

BACKGROUND: potentially harmful polypharmacy is very common in older people living in aged care facilities. To date, there have been no double-blind randomised controlled studies of deprescribing multiple medications. METHODS: three-arm (open intervention, blinded intervention and blinded control) randomised controlled trial enrolling people aged over 65 years (n = 303, noting pre-specified recruitment target of n = 954) living in residential aged care facilities. The blinded groups had medications targeted for deprescribing encapsulated while the medicines were deprescribed (blind intervention) or continued (blind control). A third open intervention arm had unblinded deprescribing of targeted medications. RESULTS: participants were 76% female with mean age 85.0 ± 7.5 years. Deprescribing was associated with a significant reduction in the total number of medicines used per participant over 12 months in both intervention groups (blind intervention group -2.7 medicines, 95% CI -3.5, -1.9, and open intervention group -2.3 medicines; 95% CI -3.1, -1.4) compared with the control group (-0.3, 95% CI -1.0, 0.4, P = 0.053). Deprescribing regular medicines was not associated with any significant increase in the number of 'when required' medicines administered. There were no significant differences in mortality in the blind intervention group (HR 0.93, 95% CI 0.50, 1.73, P = 0.83) or the open intervention group (HR 1.47, 95% CI 0.83, 2.61, P = 0.19) compared to the control group. CONCLUSIONS: deprescribing of two to three medicines per person was achieved with protocol-based deprescribing during this study. Pre-specified recruitment targets were not met, so the impact of deprescribing on survival and other clinical outcomes remains uncertain.

Validation of a liquid chromatography-tandem mass spectrometry method for simultaneous quantification of N,N-dimethylacetamide and N-monomethylacetamide in pediatric plasma.

N,N-dimethylacetamide is an excipient used in intravenous busulfan formulations, a drug used in hematopoietic stem cell transplantation conditioning. The aim of this study was to develop and validate a liquid chromatography-tandem mass spectrometry method for simultaneous quantification of N,N-dimethylacetamide, and its metabolite N-monomethylacetamide in plasma from children receiving busulfan. A 4 µl aliquot of patient plasma was extracted using 196 µl 50% methanol solution and quantified against calibrators prepared in the extraction solvent given negligible matrix effects across three concentrations. 9 [H2 ]-N,N-dimethylacetamide was used as an internal standard. Separation of N,N-dimethylacetamide and N-monomethylacetamide was achieved using a Kinetex EVO C18 stationary phase (100 mm × 2.1 mm × 2.6 µm) running an isocratic mobile phase of 30% methanol containing 0.1% formic acid at a flow of 0.2 ml/min over 3.0 min. The injection volume was 1 µl. Calibration curves for N,N-dimethylacetamide and N-monomethylacetamide were linear up to 1200 and 200 µg/L, respectively, with a lower limit of quantification 1 µg/L for both analytes. Calibrator accuracy and precision were within ± 10% of the test parameters across four concentration levels. Analytes were stable over 14 days at three different storage conditions. This method was successfully applied to measure N,N-dimethylacetamide and N-monomethylacetamide concentrations in a total of 1265 plasma samples from 77 children.

The smallest worthwhile change on function from a self-management intervention for non-persistent low back pain.

PURPOSE: To determine: (1) the smallest change in function patients would need to see following a self-management intervention for low back pain (LBP) to consider it worthwhile; (2) the association between patient-related factors and the magnitude of the smallest worthwhile change. METHODS: A cross-sectional analysis of 212 participants of the TEXT4myBACK randomised trial was conducted. At baseline, participants nominated the smallest change in function (0-30 scale) following a self-management program they would need to reach to consider it worthwhile. A multivariate regression model estimated the effects of demographic, comorbidities, lifestyle and LBP-related factors on the smallest worthwhile change estimates. RESULTS: On average, people with LBP need to experience an improvement of at least 9.4 points (SD: 5.7) in function to consider a self-management intervention worthwhile. Only baseline function severity was significantly associated with the smallest worthwhile estimate (-0.60; 95%CI - 0.76, - 0.44). CONCLUSION: On average, an improvement of 9.4 points (or 31%) in function is considered by people with LBP as the smallest change that makes self-management worthwhile. Those with lower levels of function needed to experience greater improvements.

Australian emergency department care for older adults diagnosed with low back pain of lumbar spine origin: a retrospective analysis of electronic medical record system data (2016-2019).

BACKGROUND: In Australian emergency departments, 30% of all back pain presentations are for older adults. Relatively little is known about the care that this population receives during an emergency department stay, including admission to hospital. The aim of this study is to describe emergency department management of older adults diagnosed with a lumbar spine condition and to determine predictors of healthcare use in this population. METHODS: A retrospective analysis of electronic medical record data of adults aged ≥ 65 years with a lumbar spine discharge diagnosis. Demographic, clinical care (date and time of presentation and discharge, length of stay in the emergency department, mode of arrival, triage category, re-presentations to the emergency department (within 48 h), discharge mode, the administration of pain-relieving medicines, lumbar imaging, and laboratory tests) and costs data were extracted from the electronic medical record system. Descriptive analyses and multilevel mixed-effects logistic regression models were performed. RESULTS: Over the period January 2016 to December 2019 there were 4,093 presentations to emergency departments by older adults with a lumbar spine discharge diagnosis (82.0% were non-specific low back pain). Most were female (58.3%), 39.9% had some form of lumbar imaging, and 34.1% were admitted to hospital. The most administered pain medicines were opioid analgesics (67.1%), followed by paracetamol (63.9%) and NSAIDs (33.0%). Predictors of healthcare use and hospital inpatient admission were receiving a laboratory test and receiving any opioid. For the financial period 2019-20, the mean (SD) total cost of care per presentation was $5,629 ($11,982). CONCLUSION: In the emergency department, more than two thirds of older adults with a lumbar spine condition received opioid analgesics. They often received imaging and laboratory tests, had high costs and were admitted to hospital. Alternative pathways of care are needed to support older adults with low back pain, to receive guideline-concordant emergency department care and have good health outcomes.

Targeting neurotrophic factors for low back pain and sciatica: a systematic review and meta-analysis.

OBJECTIVES: This meta-analysis aims to investigate the efficacy and safety of medicines that target neurotrophic factors for low back pain (LBP) or sciatica. METHODS: We searched published and trial registry reports of randomized controlled trials evaluating the effect of medicines that target neurotrophic factors to LBP or sciatica in seven databases from inception to December 2020. Two reviewers independently identified studies, extracted data, and assessed the risk of bias and certainty in the evidence. RESULTS: Nine studies (3370 participants) were included in the meta-analyses. Low certainty evidence showed that anti-nerve growth factor (NGF) may reduce pain at 4 weeks (mean difference [MD] -6.75, 95% CI: -8.61, -4.90) and 12 weeks (MD -6.16, 95% CI: -8.38, -3.94), and may increase adverse effects for chronic LBP (odds ratio [OR] 1.18, 95% CI: 1.01, 1.38). Higher doses of anti-NGF may offer a clinically important reduction in pain at the cost of increased adverse effects for chronic LBP. Very low certainty evidence showed that anti-NGF and glial cell line-derived neurotrophic factor (pro-GDNF) may not reduce pain for sciatica at 4 weeks (MD -1.40, 95% CI: -8.26, 5.46), at 12 weeks (MD -2.91, 95% CI: -13.69, 7.67) and may increase adverse effects for sciatica (OR 3.27, 95% CI: 1.78, 6.00). CONCLUSION: Anti-NGF may offer small reductions in pain intensity for chronic LBP. The effect may depend on the dose and types of medicines. For sciatica, anti-NGF or pro-GDNF may not reduce pain. Medicines that target neurotrophic factors for LBP or sciatica are associated with different adverse effects compared to those observed in commonly prescribed medicines for these conditions.

Immunomodulatory effects of pharmaceutical opioids and antipyretic analgesics: Mechanisms and relevance to infection.

Understanding how pharmaceutical opioids and antipyretic analgesics interact with the immune system potentially has major clinical implications for management of patients with infectious diseases and surgical and critical care patients. An electronic search was carried out on MEDLINE, EMBASE, PsycINFO, CENTRAL and the Cochrane library to identify reports describing the immunomodulatory effects of opioid analgesics and antipyretic analgesics, and their effects in infectious diseases. In adaptive immunity, nonsteroidal anti-inflammatory drugs have divergent effects: augmenting cell-mediated immunity but inhibiting humoral immunity. Nonsteroidal anti-inflammatory drugs have demonstrated a beneficial role in Mycobacterium tuberculosis infection and histoplasmosis in animals, and may be plausible adjuvants to antimicrobial agents in these diseases. There is a need to evaluate these findings rigorously in human clinical trials. There is preliminary evidence demonstrating antiviral effects of indomethacin in SARS CoV-2 in vitro; however, uncertainty regarding its clinical benefit in humans needs to be resolved in large clinical trials. Certain opioid analgesics are associated with immunosuppressive effects, with a developing understanding that fentanyl, morphine, methadone and buprenorphine suppress innate immunity, whilst having diverse effects on adaptive immunity. Morphine suppresses key cells of the innate immunity and is associated with greater risk of infection in the postsurgical setting. Efforts are needed to achieve adequate analgesia whilst avoiding suppression of the innate immunity in the immediate postoperative period caused by certain opioids, particularly in cancer surgery.

Physiologically-based pharmacokinetic model predictions of inter-ethnic differences in imatinib pharmacokinetics and dosing regimens.

AIMS: This study implements a physiologically-based pharmacokinetic (PBPK) modelling approach to investigate inter-ethnic differences in imatinib pharmacokinetics and dosing regimens. METHODS: A PBPK model of imatinib was built in the Simcyp Simulator (version 17) integrating in vitro drug metabolism and clinical pharmacokinetic data. The model accounts for ethnic differences in body size and abundance of drug-metabolising enzymes and proteins involved in imatinib disposition. Utility of this model for prediction of imatinib pharmacokinetics was evaluated across different dosing regimens and ethnic groups. The impact of ethnicity on imatinib dosing was then assessed based on the established range of trough concentrations (Css,min ). RESULTS: The PBPK model of imatinib demonstrated excellent predictive performance in describing pharmacokinetics and the attained Css,min in patients from different ethnic groups, shown by prediction differences that were within 1.25-fold of the clinically-reported values in published studies. PBPK simulation suggested a similar dose of imatinib (400-600 mg/d) to achieve the desirable range of Css,min (1000-3200 ng/mL) in populations of European, Japanese and Chinese ancestry. The simulation indicated that patients of African ancestry may benefit from a higher initial dose (600-800 mg/d) to achieve imatinib target concentrations, due to a higher apparent clearance (CL/F) of imatinib compared to other ethnic groups; however, the clinical data to support this are currently limited. CONCLUSION: PBPK simulations highlighted a potential ethnic difference in the recommended initial dose of imatinib between populations of European and African ancestry, but not populations of Chinese and Japanese ancestry.

Dose equivalence between metaraminol and norepinephrine in critical care.

AIMS: The aim of this study was to determine the conversion dose ratio between continuous infusion metaraminol and norepinephrine in critically ill patients with shock. METHODS: A retrospective cohort study was conducted in adult patients with shock admitted to an intensive care unit from 29 October 2018 to 30 October 2019 and who transitioned from metaraminol monotherapy to norepinephrine monotherapy. Mean arterial pressure (MAP) and infusion doses for both drugs were collected at hourly intervals; 2 hours before to 5 hours after switching from metaraminol monotherapy to norepinephrine monotherapy. The conversion dose ratio was defined as the ratio of metaraminol (µg.kg-1 .min-1) : norepinephrine (µg.kg-1 .min-1 ) required to achieve a similar MAP. RESULTS: A total of 43 out of 144 eligible patients were included. The median age was 68 years (IQR 56-76) and 22 (51%) were male. There was no significant difference between the baseline MAP during metaraminol monotherapy (median 71 mm Hg, IQR 66-76) and the post-transition MAP during norepinephrine monotherapy (median 70 mm Hg, IQR 66-73) (P = .09). The median conversion dose ratio between metaraminol and norepinephrine was 13 (IQR 7-24). In the sensitivity analyses, the median conversion dose ratio using the maximum and the mean norepinephrine infusion dose was 8 (IQR 5-16) and 12 (IQR 8-23), respectively. CONCLUSION: A conversion dose ratio of 10:1 (metaraminol µg.kg-1 .min-1 :norepinephrine µg.kg-1 .min-1 ) may be used in critically ill patients with shock to account for ease of calculations and variability of the conversion ratio in the primary and sensitivity analyses.

Physiologically based pharmacokinetic model predictions of natural product-drug interactions between goldenseal, berberine, imatinib and bosutinib.

PURPOSE: This study implements a physiologically based pharmacokinetic (PBPK) modelling approach to predict the effect of hydrastine and berberine, two major alkaloids present in goldenseal extract, on pharmacokinetics of imatinib and bosutinib. METHODS: PBPK models of hydrastine and berberine were developed in the Simcyp Simulator (version 17), integrating prior in vitro knowledge and published clinical pharmacokinetic data. The models account for reversible and irreversible (mechanism-based) inhibition of CYP3A enzymes as well as inhibition of the P-glycoprotein transporter. Inhibitory potencies of hydrastine and berberine on imatinib and bosutinib were estimated based on in vitro inhibition of metabolite formation. RESULTS: The PBPK models provided reliable estimates on the magnitude of interactions due to co-administration of goldenseal extract or high-dose berberine on substrates of CYP3A enzymes (midazolam, indinavir and cyclosporine) and P-glycoprotein (digoxin). PBPK simulations predicted a moderate twofold increase (5th to 95th percentiles of prediction of 1.4-3.1) in systemic exposure (AUC) of bosutinib when co-administered with clinically relevant doses of goldenseal extract. A high dose of berberine (300 mg thrice daily) was also expected to affect bosutinib exposure, albeit to a lesser extent than that predicted with goldenseal (AUC ratio of 1.3, 5th to 95th percentile: 1.1-1.6). Conversely, the corresponding effects on imatinib exposure are unlikely to be of clinical importance (predicted AUC ratios of 1.0-1.2). CONCLUSION: PBPK model-based predictions highlighted potential clinically significant interactions between goldenseal extract and bosutinib, but not imatinib. Dose adjustment may need to be considered if co-administration is desirable. These findings should be confirmed with optimally designed controlled drug interaction studies.