Drug dosing in obese adults

Obesity may extend the time required to reach a steady-state 25(OH)D level after initiating vitamin D supplementation

Obesity is known to influence the circulating 25(OH)D level but less is known about whether it influences the time required to reach a stable 25(OH)D level after initiating vitamin D supplementation. This observational study was done to investigate whether BMI modified the time required to reach a steady-state 25(OH)D level in response to vitamin D supplementation. Participants in the Boston STOP IT study who were treated for 12 mo with 700 IU of vitamin D3 and 500 mg of calcium daily and had 25(OH)D measures at 0, 6, and 12 mo, were included. We assessed the trajectory of 25(OH)D levels by baseline BMI category (normal weight, BMI 18.5-24.9 kg/m2, n = 62; overweight and obese, BMI ≥ 25 kg/m2, n = 105). Baseline 25(OH)D levels were 78 ± 31.3 nmol/L (normal weight) and 74.7 ± 36.5 nmol/L (overweight and obese). In a linear mixed model examining the influence of time and baseline BMI category on change in the mean 25(OH)D level, there was a significant time x BMI group interaction (p = .024. The normal weight participants had reached steady-state 25(OH)D levels by 6 mo whereas 25(OH)D levels continued to rise between 6 and 12 mo in the overweight and obese participants. This analysis suggests that the time required to reach a steady-state 25(OH)D level after initiating vitamin D supplementation in overweight and obese adults is greater than the usual 3-mo time point commonly used in clinical practice. A more refined definition of the time course of circulating 25(OH)D response to supplementation is needed in overweight and obese individuals in order to optimize clinical monitoring of vitamin D status.

Care of patients with obesity in the Emergency Department: a joint position statement from the Brazilian Association of Emergency Medicine (ABRAMEDE) and the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO)

This document presents a joint position statement from the Brazilian Association of Emergency Medicine (ABRAMEDE) and the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO) regarding the management of patients with obesity in the Emergency Department. It aimed to provide recommendations for healthcare professionals and policymakers to ensure the provision of appropriate care for patients with obesity, considering their unique needs and the challenges that arise in emergency settings. The position statement addresses key issues such as the need for structural adaptations, specific equipment, and specialized training for healthcare teams. It emphasizes the complexity of emergency care for patients with obesity due to factors such as difficulties in physical examination, imaging, vascular access, and airway management. The document also discusses the prevalence of obesity, its classification, and its impact on health outcomes. It highlights the association of obesity with numerous comorbidities, including type 2 diabetes, hypertension, cardiovascular diseases, and sleep apnea. Moreover, the statement underscores the need to combat stigma and promote a supportive and respectful healthcare environment for patients with obesity. Recommendations include enhancing Emergency Department infrastructure, ensuring adequate training for professionals, and implementing public policies that support the management of obesity and its comorbidities in emergency settings.

Effect of overweight and obesity on live birth rate in single euploid frozen embryo transfers

RESEARCH QUESTION

Does endometrial preparation using a natural cycle lead to higher live birth rates (LBR) in single euploid frozen embryo transfers (FET) compared with programmed cycles, for women who are normal weight, overweight and obese.

DESIGN

Retrospective study of 845 single euploid FETs from 688 couples. Patients were stratified by body mass index (BMI) into normal weight, overweight and obesity class I/II categories. Outcome was LBR.

RESULTS

After achieving covariate (female age, anti-Müllerian hormone, embryo quality and infertility type) balance in each stratum, the effective sample size was 481 and 262 for the programmed cycles and natural cycles, respectively. The programmed cycle approach (vaginal luteal phase support with 3 × 100 mg micronized vaginal progesterone per day) was associated with significantly lower LBR in the weighted regression analysis of the cohort (RR 0.80, 95% CI 0.73 to 0.88, P < 0.001), compared with the natural cycle approach. The effect was significantly modified by BMI (P = 0.003 but was significant for all BMI categories. Reduction in live birth was less pronounced in patients with normal weight or who were overweight BMI (RR 0.87, 95% CI 0.78 to 0.97, P = 0.014) compared with patients with class I/II obesity (RR 0.61, 95% CI 0.49 to 0.75, P < 0.001).

CONCLUSIONS

A natural cycle endometrial preparation approach leads to overall better LBR in single euploid FET. The most significant difference is observed in women with higher BMI. Overweight or obese patients undergoing hormone replacement therapy may require a higher dosage of progesterone for luteal phase support.

A Retrospective Study Evaluating the Safety and Clinical Impact of High Dose (6.75 grams) Piperacillin-Tazobactam Dosing in Critically Ill Obese Patients for Pneumonia

Background: Piperacillin-tazobactam (PTZ) demonstrates time-dependent bactericidal activity, potentially increasing the need for higher dosing in obese and critically ill patients. However, limited information is available on the safety of higher dosing strategies. Objective: To evaluate the safety and clinical impact of high dose 6.75 g IV PTZ for the treatment of pneumonia in critically ill, obese (≥120 kg) patients vs standard dose 4.5 g IV PTZ. Methods: Retrospective, cohort study, multicenter in health-system consisting of four acute-care teaching hospitals. Adult patients weighing at least 120 kg on PTZ for pneumonia in the intensive care unit (ICU) from January 2013 to September 2018 were included. The primary outcome of the study was acute nephrotoxicity defined as initiation of renal replacement therapy and/or serum creatinine increase within 48 hours of last PTZ dose. Secondary outcomes included thrombocytopenia, 14-day all-cause mortality, and ICU length of stay (LOS). Results: One hundred thirty-six patients were included with 52 and 84 in 4.5 g PTZ and 6.75 g PTZ respectively. The rate of acute nephrotoxicity was comparable between cohorts (50% 4.5 g vs 40.5% 6.75 g, P = 0.277). High dose PTZ was not independently associated with acute nephrotoxicity after control for selected confounders. All secondary outcomes were similar. Concomitant vancomycin and calculated supratherapeutic vancomycin area under curve were not independently associated with increased nephrotoxicity. Conclusions: High dose PTZ was not associated with increased acute nephrotoxicity, thrombocytopenia, 14-day all-cause mortality, or ICU LOS. Additionally, more robust trials are needed to fully assess the clinical impact of 6.75 g PTZ dosing for critically ill, obese patients, for pneumonia.

A randomised, placebo-controlled, phase III trial of leniolisib in activated phosphoinositide 3-kinase delta (PI3Kδ) syndrome (APDS): Adolescent and adult subgroup analysis

Activated phosphoinositide 3-kinase delta (PI3Kδ) syndrome (APDS) is an ultra-rare, progressive genetic disease, characterised by immune deficiency and dysregulation, affecting individuals from birth. In a 12-week phase III randomised placebo-controlled trial, leniolisib, a selective PI3Kδ inhibitor, was well-tolerated and met both co-primary endpoints (change from Baseline in log10-transformed sum of product of diameters of index lymph nodes and percentage of naïve/total B cells at Day 85). Here, prespecified subgroup analyses are reported in adolescents aged 12-17 years (leniolisib, n = 8; placebo, n = 4) and adults aged ≥18 (leniolisib, n = 13; placebo, n = 6). In both subgroups, leniolisib reduced lymphadenopathy (least squares mean change versus placebo: adolescents, -0.4 versus -0.1; adults, -0.3 versus 0.1) and increased the percentage of naïve B cells (least squares mean change: adolescents, 44.5 versus -16.5; adults, 28.4 versus -1.1). Leniolisib was well-tolerated in both adolescents and adults. These results show leniolisib is an effective APDS treatment in both subpopulations. PLAIN LANGUAGE SUMMARY: What is activated PI3Kδ syndrome (APDS)? APDS is an ultra-rare disease in which the immune system does not work correctly. People with APDS have a wide range of symptoms, including infections, certain organs associated with the immune system becoming larger, and worse quality of life. These symptoms generally start in childhood. Why was this study carried out? Current treatments only treat the symptoms of APDS, rather than correcting the cause of the problem. These treatments can also have significant side effects. A new medication for APDS called leniolisib aims to treat the underlying cause of the disease. This publication reports results from a clinical trial of leniolisib which compared patients who received leniolisib with patients who received a placebo. The aim of this report was to examine these clinical trial results to understand if leniolisib is effective and safe when treating both adolescents (12-17 years old) and adults (18 years and older) with APDS. What were the results of this study? Leniolisib improved the number of certain immune cells, compared to patients who did not receive leniolisib, in both adolescents and adults with APDS. Leniolisib also reduced the size of the enlarged immune system organs in both adolescents and adults with APDS. There were no major safety concerns for either age group who received leniolisib. What do these results mean? These results show that leniolisib can help the immune system to work in a way that is closer to those without APDS. This new treatment is effective and generally well-tolerated for both adolescents and adults. These results indicate that people with APDS are able to start treatment with leniolisib during adolescence, which may slow the build-up of symptoms and may also have a positive impact on the quality of their lives.

Fractional Carbon Dioxide Laser Combined with Secukinumab in the Treatment of Refractory Psoriasis Lesions on the Lower Legs

Psoriasis is a chronic autoimmune skin disorder characterized by high morbidity and a tendency for recurrence. Although biologic therapy for lesion clearance can achieve PASI 90/100, refractory sites remain challenging to completely clear, particularly on the lower legs and elbows. To explore the efficacy of novel treatments for these resistant sites, we present a clinical observation on the safety and effectiveness of fractional carbon dioxide (CO2) laser therapy combined with secukinumab for four patients with moderate-to-severe plaque psoriasis. After receiving at least 3 months of maintenance treatment with secukinumab 300 mg, these patients received fractional CO2 laser therapy aimed at refractory sites on the lower legs. Treatments were administered every four weeks for a maximum course of 16 weeks. All four patients demonstrated improvement in the treatment of psoriasis lesions at refractory sites following the combined treatment approach. However, the degree of improvement differed among individuals. Leg Psoriasis Area and Severity Index (Leg-PASI) scores were reduced by 50% to 88%, while leg Physician's Global Assessment (PGA) scores showed a reduction of 50% to 75%. And no adverse effects were observed.

Determination of the optimal obesity-adjusted dosing weight for enoxaparin

AIMS

The ideal dosing weight metric for enoxaparin remains elusive. Dosing remains focused on actual body weight, which may inadvertently increase the risk of bleeding in those with obesity, or ideal weight, which may underdose those with obesity. Our aim was to determine the optimal obesity-adjusted enoxaparin dosing weight.

METHODS

Multisite retrospective data were collected over a 2.0-year period for those with minimum 48 h of in-hospital twice-daily enoxaparin and factor anti-Xa level 3-5 h postdose (n = 220). Multiple linear regression calculated the associated variance between a range of nominal dosing weights and factor anti-Xa levels, adjusted for renal function. Dosing weights were calculated as ideal body weight (IBW) and then adjusted for increasing percentages of weight above IBW, i.e. IBW + 10% above IBW, IBW + 20% etc. up to actual body weight. A similar approach was used for lean body weight (LBW).

RESULTS

For body mass index ≥30 kg/m2 optimal variance explained by dosing weight metrics was at IBW + 40% (23%) and similarly for LBW + 40% (23%). Using actual body weight (ABW) had lowest associated variance with factor anti-Xa levels (18%) followed by unadjusted IBW (13%) or unadjusted LBW (19%). In those with body mass index <30 kg/m2 there was similar associated variance in the ranges of IBW + 20-50% and LBW 10-40% (21%).

CONCLUSION

Compared to IBW + 40% or LBW + 40% use of ABW to calculate dose was poorly associated with factor anti-Xa levels, as was IBW or LBW. IBW + 40% and LBW + 40% require further study as a dosing weight metric and may provide a more consistent factor anti-Xa response in those with obesity.

Lung cancer and obesity: A contentious relationship (Review)

The global obesity epidemic, attributed to sedentary lifestyles, unhealthy diets, genetics and environmental factors, has led to over 1.9 billion adults being classified as overweight and 650 million living with obesity. Despite advancements in early detection and treatment, lung cancer prognosis remains poor due to late diagnoses and limited therapies. The obesity paradox challenges conventional thinking by suggesting that individuals with obesity and certain diseases, including cancer, may have an improved prognosis compared with their counterparts of a normal weight. This observation has prompted investigations to understand protective mechanisms, including potentially favorable adipokine secretion and metabolic reserves that contribute to tolerating cancer treatments. However, understanding the association between obesity and lung cancer is complex. While smoking is the primary risk factor of lung cancer, obesity may independently impact lung cancer risk, particularly in non‑smokers. Adipose tissue dysfunction, including low‑grade chronic inflammation, and hormonal changes contribute to lung cancer development and progression. Obesity‑related factors may also influence treatment responses and survival outcomes in patients with lung cancer. The impact of obesity on treatment modalities such as chemotherapy, radiotherapy and surgery is still under investigation. Challenges in managing patients with obesity and cancer include increased surgical complexity, higher rates of postoperative complications and limited treatment options due to comorbidities. Targeted interventions aimed at reducing obesity prevalence and promoting healthy lifestyles are crucial for lung cancer prevention. The impact of obesity on lung cancer is multifaceted and requires further research to elucidate the underlying mechanisms and develop personalized interventions for prevention and treatment.

Enoxaparin treatment dosing for venous thromboembolism in pediatric patients with obesity

BACKGROUND

The optimal enoxaparin dosing for treatment of venous thromboembolism (VTE) in pediatric patients with obesity remains uncertain. We described the mean enoxaparin dose required to attain anti-factor Xa (anti-Xa) levels of 0.5-1 unit/mL in pediatric patients with obesity.

METHODS

Pediatric patients with obesity (body mass index [BMI] ≥95th percentile) who received treatment dose of enoxaparin from 2013 to 2022 and had at least one appropriately timed anti-Xa level were retrospectively evaluated. Daily enoxaparin dose required to achieve an anti-Xa level of 0.5-1 unit/mL was reviewed and compared by the severity of obesity. The correlation coefficients between enoxaparin dose requirement and BMI, BMI percentile, and weight were measured by Spearman's rank correlation coefficient.

RESULTS

Pediatric patients with obesity (n = 89) required a mean enoxaparin dose of 0.8 ± 0.18 mg/kg twice daily to attain a therapeutic anti-Xa level. Children with BMI 95th-99th percentile and weight ≤100 kg achieved the target level on a significantly higher weight-based enoxaparin dose compared to BMI greater than 99th percentile (0.95 ± 0.15 vs. 0.75 ± 0.15 mg/kg twice daily; p < .001) and weight greater than 100 kg (0.95 ± 0.14 vs. 0.7 ± 0.12 mg/kg twice daily; p < .001). BMI, BMI percentile, and weight showed a moderate to strong negative correlation with enoxaparin dose requirement.

CONCLUSIONS

Pediatric patients with obesity required a lower weight-based dose of enoxaparin to achieve a therapeutic anti-Xa than the recommended starting dose of 1 mg/kg twice daily for treatment of VTE. Among obesity indices, weight showed the strongest negative correlation with total daily enoxaparin requirement.

Designing the Prolonged Field Care Kit (PFAK) to Address the Logistical Challenges of Future Combat Casualty Care

INTRODUCTION

Prolonged Casualty Care (PCC) is a military adaptation aimed at providing pre-hospital care in austere settings when evacuation is delayed or even impossible. Current lack of standardized medical equipment and size/weight restrictions of military packs during dismounted operations hinder effective PCC. We sought to design a standardized, practical, and effective prolonged field care kit (PFAK) to enable widespread implementation of PCC.

MATERIALS AND METHODS

We reviewed Joint Trauma System Clinical Practice Guidelines to generate a list of potential contents of the PFAK. We obtained Institutional Review Board (IRB) exemption and then conducted stakeholder surveys of combat casualty care experts across the Joint Trauma System using a modified Delphi survey approach. We established a civil-military working group that provided in-depth qualitative feedback on the PFAK contents and provided an initial design of a long-range medical rucksack (LMR) to house it. Responses were analyzed using mean rank scores to help determine initial components of the PFAK. Tactical subject-matter experts tested and evaluated the PFAK and LMR prototype in austere conditions to refine the design.

RESULTS

Review of the PCC Clinical Practice Guidelines generated 49 medications and 301 potential supplies as potential PFAK contents. The first Delphi survey was sent to 100 stakeholders (overall response rate of 60%). After the first survey, contents were narrowed to a list of the most essential 27 medications and 105 other components. Iterative prototypes of the PFAK and LMR were tested to determine ergonomics, portability, flexibility, and equipment compartmentalization to facilitate use in emergencies. The prototype was optimized to address the clinical, logistical, and tactical requirements of PCC across a variety of platforms and environmental conditions.

CONCLUSIONS

Given the changing battlefield environment, efficient and effective PCC will play an increasingly important role in the management of combat trauma. The PFAK can meet this need by providing a practical and standardized resuscitation kit generated by expert military and trauma personnel consensus, carried conveniently in the LMR.

Effect of Obesity on the Use of Antiarrhythmics in Adults With Atrial Fibrillation: A Narrative Review

BACKGROUND

Atrial fibrillation (AF) and obesity coexist in approximately 37.6 million and 650 million people globally, respectively. The anatomical and physiological changes in individuals with obesity may influence the pharmacokinetic properties of drugs.

AIM

This review aimed to describe the evidence of the effect of obesity on the pharmacokinetics of antiarrhythmics in people with AF.

METHODS

Three databases were searched from inception to June 2023. Original studies that addressed the use of antiarrhythmics in adults with AF and concomitant obesity were included.

RESULTS

A total of 4549 de-duplicated articles were screened, and 114 articles underwent full-text review. Ten studies were included in this narrative synthesis: seven cohort studies, two pharmacokinetic studies, and a single case report. Samples ranged from 1 to 371 participants, predominately males (41%-85%), aged 59-75 years, with a body mass index (BMI) of 23-66 kg/m2. The two most frequently investigated antiarrhythmics were amiodarone and dofetilide. Other drugs investigated included diltiazem, flecainide, disopyramide, propafenone, dronedarone, sotalol, vernakalant, and ibutilide. Findings indicate that obesity may affect the pharmacokinetics of amiodarone and sodium channel blockers (e.g., flecainide, disopyramide, and propafenone). Factors such as drug lipophilicity may also influence the pharmacokinetics of the drug and the need for dose modification.

DISCUSSION

Antiarrhythmics are not uniformly affected by obesity. This observation is based on heterogeneous studies of participants with an average BMI and poorly controlled confounding factors such as multimorbidity, concomitant medications, varying routes of administration, and assessment of obesity. Controlled trials with stratification at the time of recruitment for obesity are necessary to determine the significance of these findings.

Sex Differences in the Pharmacokinetics of Cannabidiol and Metabolites Following Oral Administration of a Cannabidiol-Dominant Cannabis Oil in Healthy Adults

Introduction: Oral cannabidiol (CBD) product use is increasingly growing among women; however, there is a lack of data on sex differences in the pharmacokinetics (PKs) of CBD and its primary metabolites, 7-hydroxy-CBD (7-OH-CBD) and 7-carboxy-CBD (7-COOH-CBD), after repeated doses. Materials and Methods: The present study is a secondary analysis of data from a randomized, double-blind, placebo-controlled multiple-dose trial of a commercially available, CBD-dominant oral cannabis product. Healthy participants (n=17 males and 15 females) were randomized to receive 120 to 480 mg of CBD daily for 7 days. Dosing groups were pooled for all analyses due to sample size limitations. Analyses compared plasma PK parameters by sex, day, and sex×day. Results: For raw PK parameters for CBD and metabolites, there were no statistically significant effects of sex×day or sex (all p-values >0.05). For metabolite-to-parent ratios (MPRs) of AUC0-t, there were significant effects of the sex×day interactions for 7-OH-CBD (F=6.89, p=0.016) and 7-COOH-CBD (F=5.96, p=0.021). For 7-OH-CBD, follow-up analyses showed significant simple effects of day within females (t=4.13, p<0.001), but not within males (t=0.34, p=0.73), such that 7-OH-CBD MPRs increased significantly from day 1 to 7 for females, but not for males. For 7-COOH-CBD, follow-up analyses revealed significant simple effects of day within females (t=8.24, p<0.001) and males (t=5.20, p<0.001), therefore 7-COOH-CBD MPRs increased significantly from day 1 to 7 in both sexes, but the increase was significantly greater among females than among males. Within dosing days, there were no statistically significant simple effects of sex on MPRs of 7-OH-CBD or 7-COOH-CBD. Conclusions: Females exhibited greater relative exposure to CBD metabolites in plasma over time, which may reflect sex differences in CBD metabolism or elimination. Further research assessing the safety implications of higher relative exposure to CBD metabolites over longer periods of time is warranted to mirror typical consumer use patterns.

Impact of Obesity on Echinocandin Effectiveness in Treating Candida Infections: A Retrospective Observational Cohort Study

Introduction

Echinocandins are used to treat invasive candidiasis (IC), with FDA-approved doses indicated for both obese and non-obese patients. Pharmacokinetic (PK) studies have identified subtherapeutic exposure in obese patients receiving standard doses (SDs) of echinocandins. However, research on clinical outcome differences of echinocandins' SDs between obese and non-obese patients is lacking. Therefore, this study aimed to evaluate the effectiveness of echinocandins' SDs in obese compared to normal-weight patients with IC.

Patients and Methods

This retrospective cohort study was conducted at King Saud University Medical City (KSUMC) from Jan 2017 to Feb 2023. The study included adult patients diagnosed with Candida infections who received ≥ 4 doses of echinocandins. Patients with body mass index (BMI) less than 18 kg/m2 were excluded from the study. The primary and secondary outcomes included the total length of stay (LOS), IC duration, frequency of clinical resolution and all-cause mortality.

Results

This study included 132 patients (47 obese; 85 non-obese) with a median age of 61 years. The median BMI and weight were different between the obese (34.5 kg/m2, 88 kg) and non-obese (24 kg/m2, 65 kg) groups (P= 0.01). Micafungin and caspofungin were used in 63.6% and 36.4% of patients, respectively. The total LOS and length of IC infections were similar between both groups, with median values of 29.5 days (P= 0.896) and 18 days (P = 0.160), respectively. The clinical improvement percentages were 68.1% for obese and 65.9% for non-obese patients (P= 0.797), with all-cause mortality rates at 44.7% and 42.4%, respectively (P= 0.796).

Conclusion

The study found no clinical outcome differences between obese and non-obese patients, with Similar effectiveness of the echinocandins' SDs in both groups. Further research in multi-centre settings is recommended to detect any potential differences between the two groups.

The relationship between obesity and patient-reported outcome measures in people with polymyalgia rheumatica

Objective

To examine the association between obesity and patient-reported outcome measures (PROMs) in a primary care-based cohort of people with PMR.

Methods

The PMR Cohort Study recruited people with incident PMR from 382 general practices. Self-completed questionnaires (0, 12, 24 months) captured a range of PROMs for pain, stiffness, anxiety, depression, fatigue, function and quality of life, alongside data on BMI. People were categorized as underweight/normal weight (BMI < 25kg/m2), overweight (25-29.99 kg/m2) or obese (≥30 kg/m2). Piecewise, multilevel, linear mixed-effects regression models examined relationships between BMI categories and PROMs over time, adjusting for confounding variables. Chi-squared tests examined the relationship between obesity and glucocorticoid persistence.

Results

644 people with PMR were included. At baseline, 33.9% were normal/underweight, 40.6% overweight and 25.5% obese. Compared with normal/underweight people, those with obesity had significantly worse scores for the following: pain and stiffness at 12 months; fatigue at 12 and 24 months; depression at baseline; physical function at all time points; and quality of life at baseline and 12 months. They also had significantly smaller improvements in stiffness (1.13 units on an 11-point numeric rating scale; P = 0.001) and physical function (0.14 units measured using the modified Health Assessment Questionnaire; P = 0.025) between 0 and 12 months. BMI categories did not relate to persistent glucocorticoid use at 12 months (P = 0.110) or 24 months (P = 0.166).

Conclusion

Obesity associates with poorer outcomes for a range of PROMs in people with PMR. Consideration should be given to providing weight management support to people with PMR and obesity.

Characterizing Enoxaparin's Population Pharmacokinetics to Guide Dose Individualization in the Pediatric Population

BACKGROUND AND OBJECTIVE

Pediatric dosing of enoxaparin was derived based on extrapolation of the adult therapeutic range to children. However, a large fraction of children do not achieve therapeutic anticoagulation with initial dosing. We aim to use real-world anti-Xa data obtained from children receiving enoxaparin per standard of care to characterize the population pharmacokinetics (PopPK).Author names: Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Also, kindly confirm the details in the metadata are correct.The author names are accurately presented and the metadata are correct.  METHODS: A PopPK analysis was performed using NONMEM, and a stepwise covariate modeling approach was applied for the covariate selection. The final PopPK model, developed with data from 1293 patients ranging in age from 1 day to 18 years, was used to simulate enoxaparin subcutaneous dosing for prophylaxis and treatment based on total body weight (0-18 years, TBW) or fat-free mass (2-18 years, FFM). Simulated exposures in children with obesity (body mass index percentile ≥95th percentile) were compared with those without obesity.

RESULTS

A linear, one-compartment PopPK model that included allometric scaling using TBW (<2 years) or FFM (≥2 years) characterized the enoxaparin pharmacokinetic data. In addition, serum creatinine was identified as a significant covariate influencing clearance. Simulations indicated that in patients aged <2 years, the recommended 1.5 mg/kg TBW-based dosing achieves therapeutic simulated concentrations. In pediatric patients aged ≥2 years, the recommended 1.0 mg/kg dose resulted in exposures more comparable in children with and without obesity when FFM weight-based dosing was applied.

CONCLUSION

Using real-world data and PopPK modeling, enoxaparin's pharmacokinetics were characterized in pediatric patients. Using FFM and twice-daily dosing might reduce the risk of overdosing, especially in children with obesity.

Clinical guidance for unfractionated heparin dosing and monitoring in critically ill patients

INTRODUCTION

Unfractionated heparin is a widely used anticoagulant in critically ill patients. It has a well-established safety profile and remains an attractive option for clinicians due to its short half-life and reversibility. Heparin has a unique pharmacokinetic profile, which contributes to significant inter-patient and intra-patient variability in effect. The variability in anticoagulant effect combined with heparin's short half-life mean close monitoring is required for clinical efficacy and preventing adverse effects. To optimize heparin use in critically ill patients, effective monitoring assays and dose adjustment strategies are needed.

AREAS COVERED

This paper explores the use of heparin as an anticoagulant and optimal approaches to monitoring in critically ill patients.

EXPERT OPINION

Conventional monitoring assays for heparin dosing have significant limitations. Emerging data appear to favor using anti-Xa assay monitoring for heparin anticoagulation, which many centers have successfully adopted as the standard. The anti-Xa assay appears have important benefits relative to the aPTT for heparin monitoring in critically ill patients, and should be considered for broader use.

Evaluation of the biodistribution and preliminary safety profile of a novel brain-targeted manganese dioxide-based nanotheranostic system for Alzheimer's disease

A novel brain-targeted and reactive oxygen species-activatable manganese dioxide containing nanoparticle system functionalized with anti-amyloid-β antibody (named aAβ-BTRA-NC) developed by our group has shown great promise as a highly selective magnetic resonance imaging (MRI) contrast agent for early detection and multitargeted disease-modifying treatment of Alzheimer's disease (AD). To further evaluate the suitability of the formulation for future clinical application, we investigated the safety, biodistribution, and pharmacokinetic profile of aAβ-BTRA-NC in a transgenic TgCRND8 mouse AD model, wild type (WT) littermate, and CD-1 mice. Dose-ascending studies demonstrated that aAβ-BTRA-NC was well-tolerated by the animals up to 300 μmol Mn/kg body weight [b.w.], 3 times the efficacious dose for early AD detection without apparent adverse effects; Histopathological, hematological, and biochemical analyses indicated that a single dose of aAβ-BTRA-NC did not cause any toxicity in major organs. Immunotoxicity data showed that aAβ-BTRA-NC was safer than commercially available gadolinium-based MRI contrast agents at an equivalent dose of 100 μmol/kg b.w. of metal ions. Intravenously administered aAβ-BTRA-NC was taken up by main organs with the order of liver, kidneys, intestines, spleen, followed by other organs, and cleared after one day to one week post injection. Pharmacokinetic analysis indicated that the plasma concentration profile of aAβ-BTRA-NC followed a 2-compartmental model with faster clearance in the AD mice than in the WT mice. The results suggest that aAβ-BTRA-NC exhibits a strong safety profile as a nanotheranostic agent which warrants more robust preclinical development for future clinical applications.

Population Pharmacokinetics of Dasatinib in Healthy Subjects

BACKGROUND AND OBJECTIVES

Dasatinib is one of the tyrosine kinase inhibitors. The main use of these agents is inhibition of cancerous cell proliferation. The therapeutic importance of tyrosine kinase inhibitors raises the necessity of many types of investigations, especially the pharmacokinetic analysis of these drugs in humans. This analysis, along with other investigations and clinical research, will contribute to the overall knowledge of the drug. This study focused on the population pharmacokinetics of dasatinib. The objective of the study was to investigate the sources of the variability of dasatinib in a population pharmacokinetics study in healthy participants.

METHODS

We utilized 4180 plasma observations from 110 subjects who were administered SPRYCEL® on two separate occasions under fasting conditions; data from 20% of the subjects (22 subjects) were extracted for the purpose of internal model evaluation and data from 88 subjects were used in modeling. The model was evaluated by visual predictive check of three different datasets. A two-compartmental model with first order absorption and transit compartment was considered the simplest base model to describe the data based on the corrected Bayesian information criterion evaluation. Covariates were tested through conditional sampling for the stepwise approach-screening procedure in Monolix 2020R1 version. Conditional sampling for the stepwise approach was used to include the correlated covariates within the base model in the forward inclusion step and then to eliminate them backwardly to ensure that the key covariates were kept in the model at the final stage.

RESULTS

The effect of body mass index on the absorption rate constant was considered as significant covariate in the final established model. Visual predictive check for simulations, 20% of the original dataset (internal dataset) and an external dataset demonstrated the appropriateness of the final model.

CONCLUSIONS

Population pharmacokinetic modeling was performed to describe dasatinib pharmacokinetics in healthy subjects. Body mass index was considered as a factor that might be used in the future along with studies on patients to adjust the dosing regimens.

KEY POINTS

Dasatinib is classified as a highly variable drug; this variability was demonstrated in the study by the effect of body mass index on the absorption rate constant.

Reporting on patient's body mass index (BMI) in recent clinical trials for patients with breast cancer: a systematic review

BACKGROUND

The proportion of patients with breast cancer and obesity is increasing. While the therapeutic landscape of breast cancer has been expanding, we lack knowledge about the potential differential efficacy of most drugs according to the body mass index (BMI). Here, we conducted a systematic review on recent clinical drug trials to document the dosing regimen of recent drugs, the reporting of BMI and the possible exclusion of patients according to BMI, other adiposity measurements and/or diabetes (leading comorbidity of obesity). We further explored whether treatment efficacy was evaluated according to BMI.

METHODS

A search of Pubmed and ClinicalTrials.gov was performed to identify phase I-IV trials investigating novel systemic breast cancer treatments. Dosing regimens and exclusion based on BMI, adiposity measurements or diabetes, documentation of BMI and subgroup analyses according to BMI were assessed.

RESULTS

495 trials evaluating 26 different drugs were included. Most of the drugs (21/26, 81%) were given in a fixed dose independent of patient weight. BMI was an exclusion criterion in 3 out of 495 trials. Patients with diabetes, the leading comorbidity of obesity, were excluded in 67/495 trials (13.5%). Distribution of patients according to BMI was mentioned in 8% of the manuscripts, subgroup analysis was performed in 2 trials. No other measures of adiposity/body composition were mentioned in any of the trials. Retrospective analyses on the impact of BMI were performed in 6 trials.

CONCLUSIONS

Patient adiposity is hardly considered as most novel drug treatments are given in a fixed dose. BMI is generally not reported in recent trials and few secondary analyses are performed. Given the prevalence of patients with obesity and the impact obesity can have on pharmacokinetics and cancer biology, more attention should be given by investigators and study sponsors to reporting patient's BMI and evaluating its impact on treatment efficacy and toxicity.

Impact of Obesity on Hepatic Drug Clearance: What are the Influential Variables?

Drug clearance in obese subjects varies widely among different drugs and across subjects with different severity of obesity. This study investigates correlations between plasma clearance (CLp) and drug- and patient-related characteristics in obese subjects, and evaluates the systematic accuracy of common weight-based dosing methods. A physiologically-based pharmacokinetic (PBPK) modeling approach that uses recent information on obesity-related changes in physiology was used to simulate CLp for a normal-weight subject (body mass index [BMI] = 20) and subjects with various severities of obesity (BMI 25-60) for hypothetical hepatically cleared drugs with a wide range of properties. Influential variables for CLp change were investigated. For each drug and obese subject, the exponent that yields perfect allometric scaling of CLp from normal-weight subjects was assessed. Among all variables, BMI and relative changes in enzyme activity resulting from obesity proved highly correlated with obesity-related CLp changes. Drugs bound to α1-acid glycoprotein (AAG) had lower CLp changes compared to drugs bound to human serum albumin (HSA). Lower extraction ratios (ER) corresponded to higher CLp changes compared to higher ER. The allometric exponent for perfect scaling ranged from -3.84 to 3.34 illustrating that none of the scaling methods performed well in all situations. While all three dosing methods are generally systematically accurate for drugs with unchanged or up to 50% increased enzyme activity in subjects with a BMI below 30 kg/m2, in any of the other cases, information on the different drug properties and severity of obesity is required to select an appropriate dosing method for individuals with obesity.

Updated antimicrobial dosing recommendations for obese patients

The prevalence of obesity has increased considerably in the last few decades. Pathophysiological changes in obese patients lead to pharmacokinetic (PK) and pharmacodynamic (PD) alterations that can condition the correct exposure to antimicrobials if standard dosages are used. Inadequate dosing in obese patients can lead to toxicity or therapeutic failure. In recent years, additional antimicrobial PK/PD data, extended infusion strategies, and studies in critically ill patients have made it possible to obtain data to provide a better dosage in obese patients. Despite this, it is usually difficult to find information on drug dosing in this population, which is sometimes contradictory. This is a comprehensive review of the dosing of different types of antimicrobials (antibiotics, antifungals, antivirals, and antituberculosis drugs) in obese patients, where the literature on PK and possible dosing strategies in obese adults was critically assessed.

Acyclovir dosing in herpes encephalitis: A scoping review

BACKGROUND

Herpes encephalitis, a rare yet potentially fatal viral infection, is treated exclusively with acyclovir, the sole antiviral medication used for this condition. Acyclovir recommended dose is 10 mg/kg/dose intravenous every 8 hours; however, it is unclear what body weight should be utilized in obese patients. Using the ideal body weight may result in subtherapeutic ineffective concentrations, while utilizing the actual body weight might result in acyclovir induced adverse effects, either nephrotoxicity or neurotoxicity or both.

OBJECTIVE

The objective of this scoping review is to explore existing evidence regarding acyclovir dosing for obese patients afflicted with herpes encephalitis.

METHODS

MEDLINE, EMBASE, Scopus, Web of Science, and CINAHL databases were searched on 26 May 2023, with no language restrictions. Two independent reviewers utilized the Covidence software to carry out the screening and selection of the articles. A total of 22 articles were included in the current review.

RESULTS

The prevalence of acyclovir-associated nephrotoxicity ranged from 13% to 21%, while the prevalence of neurotoxicity was not clearly defined. However, there is lack of evidence regarding what may arise from subtherapeutic concentrations. An approach has been suggested to help clinicians to give the most appropriate acyclovir dose to herpes encephalitis patients. Patients with normal kidney function could receive the normal doses based on actual weight if normal weight and based on adjusted body weight if obese. On the other hand, if the patients are experiencing augmented renal clearance, they could receive up to the maximum recommended doses.

CONCLUSION

Overall, there is a lack of consistency on which body weight to use to calculate acyclovir dose in obese patients. So it is recommended that further studies compare the concentration of intravenous acyclovir between obese and nonobese patients and relating the resultant concentration with patient outcomes.

[An online tool to personalize the drug-doses for obese adults]

BACKGROUND

Between 1975 and 2014, the number of people suffering from obesity tripled, reaching 17% of the adult population in France and more than 35% in the United States. Obesity is defined by a Body Mass Index (BMI)>30kg/m2 and characterized by a significant accumulation of adipose tissue responsible for the increase in weight. This accumulation leads to physiological changes capable of modifying the pharmacokinetics of drugs, which can lead to the administration of inappropriate doses. For this reason, some significant dosage adjustments are necessary for obese patients. However, data on these adaptations are not easily accessible and sometimes complex to implement in practice.

AIM

To perform a new online tool allowing to calculate and propose an adjusted dose of a drug that should be administered to an obese patient.

METHOD

(i) carrying out an extensive bibliographic research according to the PRISMA methodology; and (ii) the development of a new website site proposing an adjusted dose for obese patients.

RESULTS

Firstly, 49 reviews concerning the dose adaptation have been evaluated and, secondly, 319 articles have been selected. Among them, 204 articles have been included in the database to justify the adjusted dose of 84 drugs and administration methods including antibiotics, antifungals, anticoagulants or even cancer drugs. This database is available online through a calculator on the website named Adapt'Obese. Thus, with the sex, height and weight of an obese patient, Adapt'Obese proposes a personalized and adjusted dose of the drug to administer.

PERSPECTIVES

Other drugs will be added soon, and functional improvements are planned, with the aim of adapting the dosages in obese patients, as for patients with renal insufficiency.

Influence of Weight and Body Size on the Pharmacokinetics of Heart Failure Pharmacotherapy: A Systematic Review

OBJECTIVE

To conduct a review of studies evaluating the influence of body size and weight (WT) on the pharmacokinetics (PK) of drugs recommended for heart failure (HF) treatment.

DATA SOURCES

A systematic search of the MEDLINE (1946 to April 2023) and EMBASE (1974 to April 2023) databases was conducted for articles that focused on the impact of WT or body size on the PK of drugs of interest used in HF patients.

STUDY SELECTION AND DATA EXTRACTION

Articles written in English or French related to the aim of our study were retained for analysis.

DATA SYNTHESIS

Of 6493 articles, 20 were retained for analysis. Weight was associated with the clearance of digoxin, carvedilol, enalapril, and candesartan as well as the volume of distribution of eplerenone and bisoprolol. There was no documented direct impact of WT on the PK of furosemide, valsartan, and metoprolol, although these studies were limited or confounded by the small sample size, adjustment of PK factors by WT, or the use of the Cockroff-Gault equation for the evaluation of creatinine clearance, which includes WT.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review highlights and summarizes the available data on the importance of WT on the PK of HF treatment.

CONCLUSION

Considering the significant impact of WT on most HF drugs in this review, it may be important to further investigate it in the context of personalized therapy, particularly in patients presenting extreme WTs.

The effect of age on clinical dose equivalency of fentanyl and morphine analgosedation in mechanically ventilated patients: Findings from the ANALGESIC trial

BACKGROUND

The dose equivalency of fentanyl vs. morphine is widely considered to be approximately 1:100. However, little is known about the effect of age on this ratio when these agents are used as infusions for analgosedation.

OBJECTIVES

To assess the impact of age on the clinical dose equivalency of fentanyl and morphine when used as infusions for analgosedation in mechanically ventilated intensive care unit patients.

METHODS

We performed a post hoc analysis of the Assessment of Opioid Administration to Lead to Analgesic Effects and Sedation in Intensive Care (ANALGESIC) cluster randomised crossover trial of fentanyl and morphine infusions for analgosedation. Dose and analgosedative clinical equivalency of fentanyl and morphine were assessed by age and by using different body-size descriptors.

RESULTS

We studied 663 patients (338 fentanyl, 325 morphine). Median (interquartile range) hourly dose of fentanyl and morphine were 58.1 (40.0-89.2) mcg and 3400 (2200-5000) mcg, respectively. The ratio of total dose of fentanyl:morphine was 1:93 in the 18- to 29-year-old group and 1:25 in the ≥80-year-old group (p = 0.015), respectively, with fentanyl becoming relatively less clinically effective as age increased. This effect was also seen when comparing dosing by different body-size descriptors with the strongest age-related change when using body surface area as body-size descriptor (p = 0.009).

CONCLUSION

The analgosedative clinical dose equivalency of fentanyl vs. morphine is heterogeneous when used as infusions for analgosedation, with fentanyl becoming relatively less clinically effective as age increases. This information can help guide prescription of these agents during transition from one agent to the other in critically ill patients.

Castelino R, Inglis SC, Davidson PM, Ferguson C. Direct oral anticoagulant use in hospitalized patients with atrial fibrillation across body mass index categories: design and rationale for a retrospective cohort study

Background

Atrial fibrillation (AF) and obesity are common conditions globally; yet, there remains suboptimal pharmacological management contributing to high rates of hospitalization in patients with AF. The altered pathophysiology of both obese and underweight individuals may influence the pharmacology of medications, including those used to manage AF. This, in turn, increases the risk of adverse events and impacts patient risk for stroke and rehospitalization. Despite the well-established complications of obesity, research investigating the relationship between obesity and AF is scant.

Objectives

The primary aim of this study is to describe cardiovascular-related hospitalization in AF patients according to BMI categories. A secondary aim is to describe anticoagulant and antiarrhythmic prescribing practice patterns in patients with AF, according to the BMI category.

Design

A retrospective, exploratory descriptive observational cohort study, using routinely collected electronic medical record data from five public hospitals within a single health district, with a population dominantly that is culturally and linguistically diverse, and has a low socioeconomic status.

Methods and analysis

Data extraction will include a 24-month period (January 2017 to December 2018) with a 12-month follow-up. All adult (⩾18 years) patients at discharge diagnosed with AF, prescribed any oral anticoagulant and/or oral rate/rhythm control agent, will be eligible for inclusion.

Ethics and dissemination

Ethics approval from the health district and the University of Wollongong has been granted. Findings will seek to demonstrate associations between management strategies and patient outcomes, as well as describe patterns of acute care management from prescribers. These data will be used to inform and generate hypotheses for large-scale studies examining the impact of body weight on anticoagulation prescribing at national and global scales.

Body composition and chemotherapy toxicities in breast cancer: a systematic review of the literature

PURPOSE

Breast cancer is the most diagnosed cancer in women with chemotherapy being a common treatment. Toxicities due to chemotherapy can result in dose reduction, delay, and early cessation of treatment, which along with causing distress for individuals during their cancer treatment might also reduce the therapeutic effect. The purpose of this systematic review is to examine the role of body composition on chemotherapy toxicities in women with breast cancer.

METHODS

A systematic search of the literature was completed on electronic databases Pubmed, Embase, CINHAHL, and Cochrane. Studies were included if the direct effect of body composition on chemotherapy toxicities was reported and excluded if body composition could not be isolated. A critical appraisal of the studies included was performed using McMasters University Critical Review Form for Quantitative Studies.

RESULTS

Eleven studies were included with a total of 2881 female participants. All studies reported significant relationships between body composition and chemotherapy toxicities; however, individual parameters differed between the studies. Adding to the heterogeneity, different thresholds were reported to determine both sarcopenia and myosteatosis, making it difficult to identify a common finding.

CONCLUSION

This review suggests that body composition may be an important factor in predicting the severity of chemotherapy toxicities during treatment for breast cancer; however, the lack of international consensus as to thresholds in the literature for sarcopenia and myosteatosis may result in bias. The review supports the need for further prospective studies, allowing for more robust, pre-determined data collection, to better understand the implications of body composition on toxicities and benefits of using body composition to individualize chemotherapy dosing.

IMPLICATIONS FOR CANCER SURVIVORS

Toxicities due to chemotherapy can result in treatment being unable to be completed as planned, potentially resulting in poorer survival outcomes. Improved knowledge in this area may give rise to a more reliable way of individualizing chemotherapy dosage to help mitigate this risk.

Obesity and its Relationship with Covid-19: A Review of the Main Pharmaceutical Aspects

Important physiological changes are observed in patients with obesity, such as intestinal permeability, gastric emptying, cardiac output, and hepatic and renal function. These differences can determine variations in the pharmacokinetics of different drugs and can generate different concentrations at the site of action, which can lead to sub therapeutic or toxic concentrations. Understanding the physiological and immunological processes that lead to the clinical manifestations of COVID-19 is essential to correlate obesity as a risk factor for increasing the prevalence, severity, and lethality of the disease. Several drugs have been suggested to control COVID- 19 like Lopinavir, Ritonavir, Ribavirin, Sofosbuvir, Remdesivir, Oseltamivir, Oseltamivir phosphate, Oseltamivir carboxylate, Hydroxychloroquine, Chloroquine, Azithromycin, Teicoplanin, Tocilizumab, Anakinra, Methylprednisolone, Prednisolone, Ciclesonide and Ivermectin. Similarly, these differences between healthy people and obese people can be correlated to mechanical factors, such as insufficient doses of the vaccine for high body mass, impairing the absorption and distribution of the vaccine that will be lower than desired or can be linked to the inflammatory state in obese patients, which can influence the humoral immune response. Additionally, different aspects make the obese population more prone to persistent symptoms of the disease (long COVID), which makes understanding these mechanisms fundamental to addressing the implications of the disease. Thus, this review provides an overview of the relationship between COVID-19 and obesity, considering aspects related to pharmacokinetics, immunosuppression, immunization, and possible implications of long COVID in these individuals.

Effective prolonged suppression of HIV-1 viral load using tenofovir alafenamide, emtricitabine and efavirenz in an adult with BMI >59 kg/m2

Limited information is available regarding the efficacy of antiretrovirals in people with HIV-1 and high or very high Body Mass Index (BMI). This is especially the case for the alafenamide salt of tenofovir as clinical trials have only enrolled patients with BMI ≤30 kg/m2. Lower concentrations of some antiretrovirals are expected in patients with BMI >30 kg/m2 due to potential changes in clearance and distribution of medication. This report describes an individual taking tenofovir alafenamide, emtricitabine and efavirenz in whom HIV-1 viral load was consistently undetectable (<50 copies/ml) over a 2.5 year period. During this period the patient's BMI ranged between 59.8 and 68.1 kg/m2. Further data is required to support the efficacy of antiretrovirals in individuals with high and very high BMI.

Is There a Need for a Dedicated Pharmacokinetic Trial for a Drug in Obese Populations? A Drug Prioritization Decision Tree Framework

Obesity is a growing global health concern associated with high comorbidity rates, leading to an increasing number of patients who are obese requiring medication. However, clinical trials often exclude or under-represent individuals who are obese, creating the need for a methodology to adjust labeling to ensure safe and effective dosing for all patients. To address this, we developed a 2-part decision tree framework to prioritize drugs for dedicated pharmacokinetic studies in obese subjects. Leveraging current drug knowledge and modeling techniques, the decision tree system predicts expected exposure changes and recommends labeling strategies, allowing stakeholders to prioritize resources toward the drugs most in need. In a case study evaluating 30 drugs from literature across different therapeutic areas, our first decision tree predicted the expected direction of exposure change accurately in 73% of cases. We conclude that this decision tree system offers a valuable tool to advance research in obesity pharmacology and personalize drug development for patients who are obese, ensuring safe and effective medication.

Low serum progesterone on day of transfer adversely impacts ongoing pregnancy rates in hormonally prepared single blastocyst frozen embryo transfer cycles

OBJECTIVE

To evaluate if serum progesterone (P) levels on the day of transfer influence ongoing pregnancy rate (OPR) in hormonally prepared single blastocyst frozen embryo transfer (FET) cycles?

STUDY DESIGN

Single center prospective cohort study conducted between June 2021 and August 2022 analyzed 217 single good quality blastocyst FET cycles hormonally prepared with oral estradiol valerate and micronized vaginal progesterone 400 mg twice daily.

RESULTS

Mean serum P on the day of embryo transfer (ET) was 9.76 ± 5.19 ng/ml. Receiver operator curve (ROC) showed a significant predictive value of serum P levels on the day of ET for OPR, with an area under curve (AUC) (95 %CI) = 0.58 (0.49-0.66). Optimal serum P threshold for OPR was 7.7 ng/ml (Sensitivity 76.8%, Specificity 43.7%). 35.9% patients had serum P below this threshold. BMI was significantly higher (26.8 ± 3.7 vs 25.6 ± 4.3; p = 0.048) in patients with serum P < 7.7 ng/ml vs ≥ 7.7 ng/ml. OPR was significantly lower (24.4% vs 45.3%; p = 0.002) and clinical miscarriage rates significantly higher (37.9% vs 19.2%; p = 0.042) if serum P < 7.72 ng/ml vs ≥ 7.7 ng/ml.

CONCLUSION

This study found that serum P level on the day of transfer in hormonally prepared FET cycles was a significant predictor of OPR.

Use of and association between heart failure pharmacological treatments and outcomes in obese versus non-obese patients with heart failure with reduced ejection fraction: data from the Swedish Heart Failure Registry

AIMS

To investigate the use of guideline-directed medical therapies (GDMT) and associated outcomes in obese (body mass index ≥30 kg/m2 ) versus non-obese patients with heart failure (HF) with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

Patients with HFrEF from the Swedish HF Registry were included. Of 16 116 patients, 24% were obese. In obese versus non-obese patients, use of treatments was 91% versus 86% for renin-angiotensin system inhibitors (RASi)/angiotensin receptor-neprilysin inhibitors (ARNi), 94% versus 91% for beta-blockers, 53% versus 43% for mineralocorticoid receptor antagonists. Obesity was shown to be independently associated with more likely use of each treatment, triple combination therapy, and the achievement of target dose by multivariable logistic regressions. Multivariable Cox regressions showed use of RASi/ARNi and beta-blockers being independently associated with lower risk of all-cause/cardiovascular death regardless of obesity, although, when considering competing risks, a lower risk of cardiovascular death with RASi/ARNi in obese versus non-obese patients was observed. RASi/ARNi were associated with lower risk of HF hospitalization in obese but not in non-obese patients, whereas beta-blockers were not associated with the risk of HF hospitalization regardless of obesity. At the competing risk analysis, RASi/ARNi use was associated with higher risk of HF hospitalization regardless of obesity.

CONCLUSION

Obese patients were more likely to receive optimal treatments after adjustment for factors affecting tolerability, suggesting that perceived beyond actual tolerance issues limit GDMT implementation. RASi/ARNi and beta-blockers were associated with lower mortality regardless of obesity, with a greater association between RASi/ARNi and lower cardiovascular death in obese versus non-obese patients when considering competing risk.

Mechanisms of Obesity-Induced Changes in Pharmacokinetics of IgG in Rats

PURPOSE

To evaluate how obesity affects the pharmacokinetics of human IgG following subcutaneous (SC) and intravenous (IV) administration to rats and the homeostasis of endogenous rat IgG.

METHODS

Differences in body weight and size, body composition, and serum concentration of endogenous rat IgG in male Zucker obese (ZUC-FA/FA) and control (ZUC-LEAN) rats were measured from the age of 5 weeks up to 30 weeks. At the age of 23-24 weeks animals received a single IV or SC dose of human IgG (1 g/kg of total body weight), and serum pharmacokinetics was followed for 7 weeks. A mechanistic model linking obesity-related changes in pharmacokinetics with animal growth and changes in body composition was developed.

RESULTS

Significant differences were observed in both endogenous and exogenous IgG pharmacokinetics between obese and control groups. The AUC for human IgG was lower in obese groups (57.6% of control after IV and 48.1% after SC dosing), and clearance was 1.75-fold higher in obese animals. The mechanistic population model successfully captured the data and included several major components: endogenous rat IgG homeostasis with age-dependent synthesis rate; competition of human IgG and endogenous rat IgG for FcRn binding and its effect on endogenous rat IgG concentrations following injection of a high dose of human IgG; and the effect of body size and composition (changing over time and dependent on the obesity status) on pharmacokinetic parameters.

CONCLUSIONS

We identified important obesity-induced changes in the pharmacokinetics of IgG. Results can potentially facilitate optimization of the dosing of IgG-based therapeutics in the obese population.

Overcorrection and undercorrection with fixed dosing of bolus hypertonic saline for symptomatic hyponatremia

OBJECTIVE

Current guidelines recommend treating symptomatic hyponatremia with rapid bolus-wise infusion of fixed volumes of hypertonic saline regardless of body weight. We hypothesize that this approach is associated with overcorrection and undercorrection in patients with low and high body weight.

DESIGN

Single-center, retrospective cohort study.

METHODS

Data were collected on patients treated with ≥1 bolus 100 or 150 mL 3% NaCl for symptomatic hyponatremia between 2017 and 2021. Outcomes were overcorrection (plasma sodium rise > 10 mmol/L/24 h, > 18 mmol/L/48 h, or relowering therapy) and undercorrection (plasma sodium rise < 5 mmol/L/24 h). Low body weight and high body weight were defined according to the lowest (≤60 kg) and highest (≥80 kg) quartiles.

RESULTS

Hypertonic saline was administered to 180 patients and caused plasma sodium to rise from 120 mmol/L to 126.4 mmol/L (24 h) and 130.4 mmol/L (48 h). Overcorrection occurred in 32 patients (18%) and was independently associated with lower body weight, weight ≤ 60 kg, lower baseline plasma sodium, volume depletion, hypokalemia, and less boluses. In patients without rapidly reversible causes of hyponatremia, overcorrection still occurred more often in patients ≤ 60 kg. Undercorrection occurred in 52 patients (29%) and was not associated with body weight or weight ≥ 80 kg but was associated with weight ≥ 100 kg and lean body weight in patients with obesity.

CONCLUSION

Our real-world data suggest that fixed dosing of bolus hypertonic saline may expose patients with low and high body weight to more overcorrection and undercorrection, respectively. Prospective studies are needed to develop and validate individualized dosing models.

Development of population pharmacokinetics model and Bayesian estimation of rifampicin exposure in Indonesian patients with tuberculosis

BACKGROUND

Interindividual variability in the pharmacokinetics (PK) of anti-tuberculosis (TB) drugs is the leading cause of treatment failure. Herein, we evaluated the influence of demographic, clinical, and genetic factors that cause variability in RIF PK parameters in Indonesian TB patients.

METHODS

In total, 210 Indonesian patients with TB (300 plasma samples) were enrolled in this study. Clinical data, solute carrier organic anion transporter family member-1B1 (SLCO1B1) haplotypes *1a, *1b, and *15, and RIF concentrations were analyzed. The population PK model was developed using a non-linear mixed effect method.

RESULTS

A one-compartment model with allometric scaling adequately described the PK of RIF. Age and SLCO1B1 haplotype *15 were significantly associated with variability in apparent clearance (CL/F). For patients in their 40s, each 10-year increase in age was associated with a 10% decrease in CL/F (7.85 L/h). Patients with the SLCO1B1 haplotype *15 had a 24% lower CL/F compared to those with the wild-type. Visual predictive checks and non-parametric bootstrap analysis indicated good model performance.

CONCLUSION

Age and SLCO1B1 haplotype *15 were significant covariates of RIF CL/F. Geriatric patients with haplotype *15 had significantly greater exposure to RIF. The model could optimize TB pharmacotherapy through its application in therapeutic drug monitoring (clinical trial no. NCT05280886).

Characterization of plasma daptomycin in patients with serum highly glycated albumin and obesity

PURPOSE

Plasma daptomycin has not been fully characterized in diabetic and obese patients. This study aimed to evaluate the associations of plasma daptomycin with glycation of serum albumin and obesity.

METHODS

Infectious patients (n = 70) receiving intravenous daptomycin were enrolled. The plasma concentration of total and free daptomycin were determined using liquid chromatograph-tandem mass spectrometer. The associations of the plasma concentrations of daptomycin with clinical factors including serum albumin fractionations and physical status (obese including overweight, body mass index ≥ 25.0) were investigated. Daptomycin doses were adjusted using total body-weight.

RESULTS

The serum albumin level was positively and negatively correlated with the plasma concentration of total daptomycin and its free fraction proportion, respectively. The serum non-glycated albumin was negatively correlated with the free fraction proportion. The dose-normalized plasma concentration of total daptomycin was higher in the obese patients than in non-obese patients when the body-weight was corrected with total and adjusted values. For the dose adjustment with lean body-weight, no difference was observed in the dose-normalized plasma concentration of total daptomycin between the physical statuses. For each body-weight correction method, physical status did not affect the dose-normalized plasma concentration of free daptomycin.

CONCLUSION

The glycation of serum albumin and obesity did not associate with dose-normalized plasma free daptomycin. In obese patients, daptomycin dosage adjustment with total body-weight and adjusted body-weight may lead to an apparent excessive exposure resulting in overdosage compared to lean body-weight.

A comparative evaluation of propranolol pharmacokinetics in obese versus ideal weight individuals: A blueprint towards a personalised medicine

The pharmacokinetics of propranolol were investigated in obese and healthy weight groups. Research studies in relation to the presented topic were gathered, evaluated, and compared to distinguish variabilities involved amongst different lipophilic drugs and how they impacted the clinical effectiveness. Propranolol is a lipophilic drug so it was predicted that the pharmacokinetics would differ between obese and ideal-weight individuals. Previous research in other lipophilic drugs shows a trend to increase the volume of distribution and half-life in obese compared to ideal weight individuals. However, the majority of both clinical and preclinical studies gathered in this review, found a decrease in the volume of distribution (V_D) and clearance, and minimal significant difference in the half-life, in the obese group when compared with the ideal weight group. Different explanations for this comparison have been theorised including differing tissue blood flow, plasma protein binding, or hepatic clearance in obese compared with ideal weight populations; though the exact reasoning as to why propranolol does not follow the general trend for lipophilic drugs is yet to be determined. These findings regarding propranolol pharmacokinetics can be utilised towards further research and development in personalised medicine for patients with obesity and comorbid cardiovascular disease. The comparative studies highlighted the pharmacokinetic parameters which demonstrated a need for personalised dosage regimes for propranolol and a proposed research direction to understand why the difference exists between these population groups. With the prevalence of obesity continuing to rise, the relative pharmacokinetics of drugs must be evaluated in obese patient groups in order to inform drug dosing regimens and improve current clinical practice.

Challenges and Possible Solutions to Direct-Acting Oral Anticoagulants (DOACs) Dosing in Patients with Extreme Bodyweight and Renal Impairment

This article aims to highlight the dosing issues of direct oral anticoagulants (DOACs) in patients with renal impairment and/or obesity in an attempt to develop solutions employing advanced data-driven techniques. DOACs have become widely accepted by clinicians worldwide because of their superior clinical profiles, more predictable pharmacokinetics, and hence more convenient dosing relative to other anticoagulants. However, the optimal dosing of DOACs in extreme bodyweight  patients and patients with renal impairment is difficult to achieve using the conventional dosing approach. The standard dosing approach (fixed-dose) is based on limited data from clinical studies. The existing formulae (models) for determining the appropriate doses for these patient groups leads to suboptimal dosing. This problem of mis-dosing is worsened by the lack of standardized laboratory parameters for monitoring the exposure to DOACs in renal failure and extreme bodyweight patients. Model-informed precision dosing (MIPD) encompasses a range of techniques like machine learning and pharmacometrics modelling, which could uncover key variables and relationships as well as shed more light on the pharmacokinetics and pharmacodynamics of DOACs in patients with extreme bodyweight or renal impairment. Ultimately, this individualized approach-if implemented in clinical practice-could optimise dosing for the DOACs for better safety and efficacy.

Generative models for age, race/ethnicity, and disease state dependence of physiological determinants of drug dosing

Dosing requires consideration of diverse patient-specific factors affecting drug pharmacokinetics and pharmacodynamics. The available pharmacometric methods have limited capacity for modeling the inter-relationships and patterns of variability among physiological determinants of drug dosing (PDODD). To investigate whether generative adversarial networks (GANs) can learn a generative model from real-world data that recapitulates PDODD distributions. A GAN architecture was developed for modeling a PDODD panel comprised of: age, sex, race/ethnicity, body weight, body surface area, total body fat, lean body weight, albumin concentration, glomerular filtration rate (EGFR), urine flow rate, urinary albumin-to-creatinine ratio, alanine aminotransferase to alkaline phosphatase R-value, total bilirubin, active hepatitis B infection status, active hepatitis C infection status, red blood cell, white blood cell, and platelet counts. The panel variables were derived from National Health and Nutrition Examination Survey (NHANES) data sets. The dependence of GAN-generated PDODD on age, race, and active hepatitis infections was assessed. The continuous PDODD biomarkers had diverse non-normal univariate distributions and bivariate trend patterns. The univariate distributions of PDODD biomarkers from GAN simulations satisfactorily approximated those in test data. The joint distribution of the continuous variables was visualized using three 2-dimensional projection methods; for all three methods, the points from the GAN simulation random variate vectors were well dispersed amongst the test data. The age dependence trend patterns in GAN data were similar to those in test data. The histograms for R-values and EGFR from GAN simulations overlapped extensively with test data histograms for the Hispanic, White, African American, and Other race/ethnicity groups. The GAN-simulated data also mirrored the R-values and EGFR changes in active hepatitis C and hepatitis B infection. GANs are a promising approach for simulating the age, race/ethnicity and disease state dependencies of PDODD.

Optimization of Drug Therapy for Heart Failure With Reduced Ejection Fraction Based on Gender

PURPOSE OF REVIEW

Over the last decades, several classes of drugs have been introduced for the treatment of patients with heart failure with reduced ejection fraction (HFrEF). Their use has been supported by randomized controlled trials that have demonstrated improved patient outcomes. However, these trials enrolled a small number of female patients and sometimes have reported gender-related differences regarding the efficacy of the treatments. The aim of this review is to revise the available data about the influence of gender on the optimal treatment and drug dose in patients with HFrEF.

RECENT FINDINGS

Several gender-related differences in terms of pharmacokinetic and pharmacodynamic characteristics of the drugs have been described. These characteristics could be responsible for a different response and tolerability in men and women also when current recommended treatment of HFrEF is considered. Some studies have shown that, in women, lower doses of beta-blockers and inhibitors of renin angiotensin aldosterone system could be equally effective than higher doses in men, whereas sacubitril/valsartan could exert its favorable effect at greater values of left ventricular ejection fraction. Although there is evidence about differences in the response to treatment of HFrEF in men and women, this has not been sufficient for differentiating current recommended therapy. Further studies should better clarify if the treatment of HFrEF should be based also on the patients' gender.

Estimating Lean Body Weight in Adults With the PAWPER XL-MAC Tape Using Actual Measured Weight as an Input Variable

Introduction

Accurate drug dose calculation in obese patients requires an estimation of lean body weight (LBW) for dosing hydrophilic medications. Inaccurate weight estimates during the management of critically ill obese adults may contribute to inaccurate drug doses and consequential poor outcomes. Existing methods of LBW estimation or measurement may be very difficult or impossible to use during emergency care. A point-of-care model that could provide rapid, accurate estimates of LBW would, therefore, be of significant clinical value.

Methods

A model was derived based using the adult version of the PAWPER XL-MAC tape. This derived model used recumbent length and measured total body weight (TBW) to estimate LBW. The derived model was used to generate LBW estimations in a random sample from National Health and Nutrition Examination Survey (NHANES) datasets (n=33,215). The benchmark outcome measure was to achieve >95% of LBW estimations within 20% of DXA-measured fat-free mass (P20>95%) and >70% of estimations within 10% of DXA-measured fat-free mass (P10>70%).

Results

The new model achieved a P20 of 99.7% and a P10 of 86.4% for LBW in the pooled sample and exceeded the minimum accuracy standards. This accuracy was maintained in both sexes, all ages, all ethnic groups, all lengths and in all habitus types.

Conclusions

The modified PAWPER XL-MAC model, using TBW as an input variable, proved to be an accurate method of LBW estimation. It could potentially have an important role in facilitating emergency drug dose calculations in critically ill or injured obese adult patients.

Review and evaluation of vancomycin dosing guidelines for obese individuals

INTRODUCTION

Vancomycin dosing decisions are informed by factors such as body weight and renal function. It is important to understand the impact of obesity on vancomycin pharmacokinetics and how this may influence dosing decisions. Vancomycin dosing guidelines use varied descriptors of body weight and renal function. There is uncertainty whether current dosing guidelines result in attainment of therapeutic targets in obese individuals.

AREAS COVERED

Literature was explored using PubMed, Embase and Google Scholar for articles from January 1980 to July 2021 regarding obesity-driven physiological changes, their influence on vancomycin pharmacokinetics and body size descriptors and renal function calculations in vancomycin dosing. Pharmacokinetic simulations reflective of international vancomycin dosing guidelines were conducted to evaluate the ability of using total, ideal and adjusted body weight, as well as Cockcroft-Gault and CKD-EPI equations to attain an area-under-the-curve to minimum inhibitory concentration ratio (AUC₂₄/MIC) target (400-650) in obese individuals.

EXPERT OPINION

Vancomycin pharmacokinetics in obese individuals remains debated. Guidelines that determine loading doses using total body weight, and maintenance doses adjusted based on renal function and adjusted body weight, may be most appropriate for obese individuals. Use of ideal body weight leads to subtherapeutic vancomycin exposure and underestimation of renal function.

Combinatorial pharmacogenomic algorithm is predictive of sertraline metabolism in patients with major depressive disorder

Pharmacogenomic testing can be used to guide medication selection in patients with major depressive disorder (MDD). Currently, there is no consensus on which gene or genes to consider in medication management. Here, we assessed the clinical validity of the combinatorial pharmacogenomic algorithm to predict sertraline blood levels in a subset of patients enrolled in the Genomics Used to Improve DEpression Decisions (GUIDED) trial. Patients who reported taking sertraline within ≤2 weeks of the screening blood draw were included. All patients received combinatorial pharmacogenomic testing, which included a weighted assessment of individual phenotypes for multiple pharmacokinetic genes relevant for sertraline (CYP2C19, CYP2B6, and CYP3A4). Sertraline blood levels were compared between phenotypes based on: 1) the pharmacokinetic portion of the combinatorial pharmacogenomic algorithm, and 2) individual genes. When evaluated separately, individual genes (for CYP2C19 and CYP2B6) and the combinatorial algorithm were significant predictors of sertraline blood levels. However, in multivariate analyses that included individual genes and the combinatorial pharmacogenomic algorithm, only the combinatorial pharmacogenomic algorithm remained a significant predictor of sertraline blood levels. These findings support the clinical validity of the combinatorial pharmacogenomic algorithm, in that it is a superior predictor of sertraline blood levels compared to individual genes.

Dosing Therapeutic Radiopharmaceuticals in Obese Patients

The prevalence of obesity has increased dramatically in the Western population. Obesity is known to influence not only the proportion of adipose tissue but also physiological processes that could alter drug pharmacokinetics. Yet, there are no specific dosing recommendations for radiopharmaceuticals in this patient population. This could potentially lead to underdosing and thus suboptimal treatment in obese patients, while it could also lead to drug toxicity due to high levels of radioactivity. In this review, relevant literature is summarized on radiopharmaceutical dosing and pharmacokinetic properties, and we aimed to translate these data into practical guidelines for dosing of radiopharmaceuticals in obese patients. For radium-223, dosing in obese patients is well established. Furthermore, for samarium-153-ethylenediaminetetramethylene (EDTMP), dose-escalation studies show that the maximum tolerated dose will probably not be reached in obese patients when dosing on MBq/kg. On the other hand, there is insufficient evidence to support dose recommendations in obese patients for rhenium-168-hydroxyethylidene diphosphonate (HEDP), sodium iodide-131, iodide 131-metaiodobenzylguanidine (MIBG), lutetium-177-dotatate, and lutetium-177-prostate-specific membrane antigen (PSMA). From a pharmacokinetic perspective, fixed dosing may be appropriate for these drugs. More research into obese patient populations is needed, especially in the light of increasing prevalence of obesity worldwide.

Does Rocuroinum Dose Adjusted Due to Lean Body Weight Provide Adequate Intubation Conditions?: A Prospective Observational Study

METHODS

This is a prospective, observational study. Patients between the ages of 18 and 65 with BMI of 18.5-34.9, who are expected to be under general anesthesia for less than 6 hours, were divided into 3 groups according to their BMI (Group 1 BMI = 18.5-24.9, Group 2 BMI = 25-29.9, Group 3 BMI = 30-34.9). These groups were randomly divided into 2 subgroups: Groups LBW; 1 LBW, 2 LBW, and 3 LBW were given rocuronium intubation dosages based on their LBW while control groups; 1K, 2K, and 3K were given 0.6 mg/kg rocuronium according to their total body weight. The data on the duration of action of rocuronium and its effects on the endotracheal intubation conditions were evaluated.

RESULTS

In Group 1, T1 time was found to be significantly longer (p=0.001). Intubation score and the use of additional rocuronium dose were found to be significantly higher in Group 1 LBW than in Group 1K (p=0.001). In Group 1, an additional rocuronium dose was needed to achieve optimal intubation conditions for subgroup 1 LBW. Rocuronium duration of action was found to be significantly longer in control groups 2 and 3, that received TBW-based dosage.

CONCLUSION

In adult patients with a BMI of 18.5 and 24.9 BMI, we report optimal intubation conditions with the LBW-adjusted rocuronium dosage. This trial is registered with NCT05476952.

Time out: should vitamin D dosing be based on patient's body mass index (BMI): a prospective controlled study

The recommended daily dose of vitamin D is 2000 IU was found to be insufficient in many patients. The objective of the present study is to find whether the daily dose of vitamin D should be based on BMI. Two hundred and thirty patients with an established vitamin D deficiency (serum level of 25 Hydroxy vitamin D3 (25OHD3) of ≤20 ng/ml) and patients with BMI ≥30 kg/m2 were included in the study. Demographic data, comorbidities and BMI were recorded. Pre-treatment and post-treatment serum 25OHD3, calcium, phosphorus and parathyroid hormone (PTH) were tested at 0-, 3- and 6-month periods. Patients were treated with a standard dose of 50 000 IU of vitamin D weekly and 600/1200 mg of calcium a day. Once their level of 25OHD3 reached ≥30 ng/ml, patients were randomised into two groups. Group A received a standard recommended maintenance dose of 2000 IU daily and Group B patients received 125 IU/kg/m2 of vitamin D3. The data were entered in the database and analysed. The mean age of Group A was 50⋅74 ± 7⋅64 years compared to 52⋅32 ± 7⋅21 years in Group B. In both groups, pre-treatment vitamin D level was ≤15 ng/ml and increased to 34⋅6 ± 2⋅6 and 33⋅7 ± 2⋅4 ng/ml at the end of 3 months treatment with a dose 50 000 IU of vitamin D3 and calcium 600/1200 mg once a day for group A and group B, respectively. At 6 months, patients in Group A 25OHD3 level was 22⋅8 ± 3⋅80 and in Group B was 34⋅0 ± 1⋅85 ng/ml (P < 0⋅001). This preliminary study suggests that obese patients need higher dosage of vitamin D than the recommended dose. It is prudent that the dosage should be based on the BMI to maintain normal levels for a healthy musculoskeletal system.

Optimizing antimicrobial use: challenges, advances and opportunities

An optimal antimicrobial dose provides enough drug to achieve a clinical response while minimizing toxicity and development of drug resistance. There can be considerable variability in pharmacokinetics, for example, owing to comorbidities or other medications, which affects antimicrobial pharmacodynamics and, thus, treatment success. Although current approaches to antimicrobial dose optimization address fixed variability, better methods to monitor and rapidly adjust antimicrobial dosing are required to understand and react to residual variability that occurs within and between individuals. We review current challenges to the wider implementation of antimicrobial dose optimization and highlight novel solutions, including biosensor-based, real-time therapeutic drug monitoring and computer-controlled, closed-loop control systems. Precision antimicrobial dosing promises to improve patient outcome and is important for antimicrobial stewardship and the prevention of antimicrobial resistance.

Direct Oral Anticoagulants in Patients with Obesity and Atrial Fibrillation: Position Paper of Italian National Association of Hospital Cardiologists (ANMCO)

The use of the direct oral anticoagulants dabigatran, rivaroxaban, apixaban and edoxaban (DOACs) offers some major advantages over warfarin and other vitamin K antagonists (VKAs). One advantage is the possibility to use a fixed dose in normal-weight patients, overweight patients and patients with obesity. However, the "one size fits all" strategy raised a concern regarding the possibility to undertreat patients with a high body mass index. No randomized controlled trials (RCTs) have ever compared VKAs and DOACs in this population. We analyzed data from the literature on DOAC pharmacokinetics and pharmacodynamics, results from the four pivotal phase III trials on non-valvular atrial fibrillation, retrospective observational studies and metanalyses. While we are aware of the limitation imposed by the absence of specific RCTs, we propose the position of the Italian Association of Hospital Cardiologists (ANMCO) on the use of DOACs in patients with obesity based on the existing evidence.