Antimicrobial dosing considerations in obese adult patients

Serum levels of D-cycloserine predict antidepressant effects in pharmacologically enhanced intermittent theta-burst stimulation

BACKGROUND

Transcranial magnetic stimulation is an important treatment option for treatment resistant major depressive disorder. Pairing stimulation with adjuncts such as the partial N-Methyl-d-Aspartate (NMDA) receptor agonist, D-Cycloserine, has emerged as a strategy to enhance treatment outcomes. However, the effects of D-Cycloserine are concentration dependent, and higher concentrations may blunt TMS-induced plasticity. This is clinically important due to the potential for accumulation with repeated dosing and individual differences in volume of distribution.

METHODS

We recruited n = 12 individuals with a moderate-severe depressive episode for a pharmacokinetic characterization of repeated D-Cycloserine dosing in the context of a 4 week (20 treatments) open-label trial pairing intermittent theta-burst stimulation (iTBS) using a weight based dose of D-Cycloserine (25 mg/17.5 kg). Prior to treatment, we serially sampled peripheral blood with a 100 mg dose for comparison. Then, serum samples were characterized in conjunction with 25 mg/17.5 kg dosing for the first, the 5th (accumulation), and the 6th (elimination) doses.

RESULTS

iTBS+D-Cycloserine was associated with a potent antidepressant effect, achieving 83.3 % response and 75.0 % remission at treatment end with no serious adverse events. Improvements in depressive symptoms were predicted by serum D-Cycloserine concentration. Although we found evidence for accumulation after five doses, the weekend hiatus was sufficient for elimination and the concentration remained within the NMDA receptor agonist range. Serum concentrations did not significantly differ between 100 mg and 25 mg/17.5 kg doses.

CONCLUSIONS

Our data confirm the antidepressant effects and safety of extended iTBS+D-Cycloserine, while highlighting the importance of adequate serum concentrations within the agonist range. Weight-based dosing may not be required by default.

Safety of high-dose daptomycin in obese patients: a multicentric retrospective study

PURPOSE

Obese patients treated with daptomycin at 4 mg/kg have a 30% increased drug exposure, potentially raising the risk of adverse events (AEs) like rhabdomyolysis. Given limited data on the safety of higher doses (10 mg/kg) in this population, this study aimed to assess the safety of high-dose daptomycin in obese patients and to identify potential AEs risk factors.

METHODS

This multicenter, retrospective observational study was conducted from June 2021 to May 2022 using medical records. Patients with a BMI > 30 kg/m2 were classified as obese. AEs assessed included: CK elevation (> 5x upper limit of normal), severe elevation (> 10x upper limit), eosinophilic pneumonia, and elevated liver enzymes. Both univariate and multivariate analyses were conducted.

RESULTS

A total of 1 303 patients were included: 970 non-obese and 333 Ob patients. These patients received an average daptomycin dose of 9.9 mg/kg based on actual body weight for an average treatment duration of 8.27 days. One-third of the patients had CK monitoring. AEs rates were 3.5% for the n-Ob group vs. 8.7% in the Ob group (p < 0.01). Ob patients had significantly higher CK levels (n-Ob, 9.5%; Ob, 20.3%; p = 0.001), and severe elevation (n-Ob, 5.2%; Ob, 10.9%; p = 0.03). Factors increasing AE risk included obesity, concomitant prescriptions of drugs with risk of rhabdomyolysis, eGFR 30-60 mL/min, and daptomycin duration (OR = 2.42; 4.34; 2.03 and 1.05, respectively, p < 0.001). On the opposite, consultation with an infectious disease specialist reduced risk (OR = 0.52, p = 0.024).

CONCLUSION

This study highlights that obese patient has a significantly increased risk of AEs with high dose of daptomycin compared to non-obese patients. Adjusted body weight dosing may be considered to reduce AEs risk.

Amikacin use in critically ill patients requiring renal replacement therapy: the AMIDIAL-ICU study

BACKGROUND

Acute kidney injury (AKI) requiring renal replacement therapy (RRT) is common in intensive care units (ICUs), yet optimal amikacin dosing in this context remains poorly understood.

METHODS

We conducted a prospective observational study across 18 French hospitals from April 2020 to January 2022. Adult ICU patients (aged > 18 years) receiving their first amikacin dose while on RRT were included. Data on demographics, RRT modalities, amikacin dosing, and therapeutic drug monitoring were collected. Using a pharmacokinetic modeling approach, we evaluated various amikacin regimens and simulated target attainment probabilities across different minimum inhibitory concentrations (MICs).

RESULTS

A total of 111 patients were included, with approximately two-thirds receiving continuous RRT. The median amikacin dose was 27 (25-30) mg/kg. Amikacin peak (Cmax) and trough concentrations were monitored in 53 (47.8%) and 76 (68.5%) patients, respectively. Continuous RRT and a history of chronic kidney disease reduced dialytic clearance. For a MIC ≤ 4 mg/L, a 15 mg/kg amikacin dose achieved Cmax/MIC and AUC/MIC targets in ≥ 90% of patients on intermittent dialysis, while 20 mg/kg was required for those on continuous dialysis. For a MIC = 8 mg/L, a 30 mg/kg dose was necessary to achieve Cmax/MIC ≥ 8.

CONCLUSIONS

Our findings highlight suboptimal adherence to amikacin monitoring guidelines in ICU patients on RRT. Using pharmacokinetic modeling, we identified amikacin dosing recommendations ranging from 15 to 35 mg/kg to optimize efficacy and minimize risks, depending on MIC and dialysis modality.

Effect of Helicobacter pylori on sleeve gastrectomy and gastric microbiome differences in patients with obesity and diabetes

BACKGROUND

Obesity and diabetes mellitus (DM) have become public health concerns worldwide. Both conditions have severe consequences and are associated with significant medical costs and productivity loss. Additionally, Helicobacter pylori infection may be a risk factor for the development of these conditions. However, whether eradicating H. pylori infection directly causes weight loss or improves insulin sensitivity is unknown.

METHODS

In this study, we confirmed the effect of sleeve gastrectomy according to the state of the gastric microbiota in 40 patients with obesity, DM, and H. pylori infection. Patients with obesity were divided into four groups: non-DM without H. pylori infection (ND), non-DM with H. pylori infection (ND-HP), DM, and DM with H. pylori infection (DM-HP) using 16S V3-V4 sequencing.

RESULTS

In the DM group, ALT, hemoglobin, HbA1c, blood glucose, and HSI significantly decreased, whereas high-density lipoprotein significantly increased. However, in the H. pylori-positive group, no significant difference was observed. The diversity of gastric microbiota decreased in the order of the ND > DM > ND-HP > DM-HP groups. We also conducted a correlation analysis between the preoperative microbes and clinical data. In the ND-HP group, most of the top 20 gastric microbiota were negatively correlated with glucose metabolism. However, H. pylori infection was positively correlated with pre-insulin levels.

CONCLUSION

Therefore, these findings indicate that patients with obesity and diabetes clearly benefit from surgery, but H. pylori infection may also affect clinical improvement.

Medication Dosing for Children With Overweight and Obesity

Approximately 14.7 million US children aged 2 to 19 years are obese. This creates significant challenges to dosing medications that are primarily weight based (mg/kg) and in predicting pharmacokinetics parameters in pediatric patients. Obese individuals generally have a larger volume of distribution (Vd) for lipophilic medications. Conversely, the Vd of hydrophilic medications may be increased or decreased owing to increased lean body mass, blood volume, and decreased percentage of total body water. They may also experience decreased hepatic clearance secondary to fatty infiltrates of the liver. Hence, obesity may affect loading dose, dosage interval, plasma half-life, and time to reach steady-state concentration for various medications. Weight-based dosing is also a cause for potential medication errors. This position statement of the Pediatric Pharmacy Association recommends that weight-based dosing should be used in patients ages <18 years who weigh <40 kg; weight-based dosing should be used in patients ≥40 kg, unless the recommended adult dose for the specific indication is exceeded; clinicians should use pharmacokinetic analysis for adjusting medications in children diagnosed with overweight and obesity; and research efforts continue to evaluate dosing of medications in children diagnosed with overweight and obesity.

Vonoprazan Dual or Triple Therapy Versus Bismuth-Quadruple Therapy as First-Line Therapy for Helicobacter pylori Infection: A Three-Arm, Randomized Clinical Trial

BACKGROUND

We compared efficacy of vonoprazan-dual or triple therapies and bismuth-quadruple therapy for treatment-naive Helicobacter pylori (HP) infection in Southern China, where primary resistance rates of clarithromycin and levofloxacin are >30%.

METHODS

This was an investigator-initiated, three-arm, randomized clinical trial in Southern China. Between March 2022 and August 2023, treatment-naïve HP-infected adults were randomly assigned to receive one of three 14-day regimens (1:1:1 ratio): vonoprazan-dual (VA-dual; vonoprazan 20 mg twice daily and amoxicillin 1 g thrice daily), vonoprazan-triple (VAC-triple; vonoprazan 20 mg/amoxicillin 1 g/clarithromycin 500 mg twice daily), or bismuth-quadruple therapy containing bismuth, esomeprazole, tetracycline, and metronidazole. Primary outcome was noninferiority in HP eradication, evaluated by UBT 4-6 weeks post-treatment by intention-to-treat (ITT) and per-protocol (PP) analysis (based on subjects who completed 14-day treatment and rechecked UBT). Bonferroni-adjusted p-value of <0.017 was used to determine statistical significance.

RESULTS

A total of 298 subjects (mean age: 35.7 ± 8.4 years; male: 134 [45.0%]; VC-dual: 100, VAC-triple: 98, bismuth-quadruple: 100) were enrolled, and 292 (98.0%) had UBT rechecked. ITT analysis showed that both VA-dual (eradication rate of 96.0%) and VAC-triple therapies (95.9%) were noninferior to bismuth-quadruple therapy (92.0%) (difference: 4.0%, 95% CI: -2.9% to 11.5%, p < 0.001; and 3.9%, 95% CI: -3.1% to 11.5%, p < 0.001, respectively). PP analysis also revealed noninferiority (96.7% or 96.7% vs. 97.4%, with difference: -2.9% and -2.9%, p = 0.009 and 0.010, respectively). The frequency of adverse events was 39.0%, 56.1%, and 71.0% in VA-dual, VAC-triple, and bismuth-quadruple therapies, respectively.

CONCLUSIONS

VA-dual and VA-triple therapies are highly effective and noninferior to bismuth-quadruple therapy in Southern China. Given the lower adverse effects and fewer antibiotic use, VA-dual therapy is the preferred first-line treatment for HP infection.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (No. ChiCTR2200056375). Registered on February 4, 2022, https://www.chictr.org.cn/showproj.aspx?proj=14131.

Risk factors analysis and construction of predictive models for acute kidney injury in overweight patients receiving vancomycin treatment

BACKGROUND

Vancomycin-induced acute kidney injury (VI-AKI) is one of its serious adverse reactions. The purpose of this study is to discuss the risk factors for VI-AKI in overweight patients and construct a clinical prediction model based on the results of the analysis.

METHODS

Multivariable logistic regression analysis was used to identify risk factors for VI-AKI and constructed nomogram models. The performance of the nomogram was evaluated based on the area under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis (DCA).

RESULT

Cancer (OR 4.186, 95% CI 1.473-11.896), vancomycin trough concentration >20.0 μg/mL (OR 6.251, 95% CI 2.275-17.180), concomitant furosemide (OR 2.722, 95% CI 1.071-6.919) and vasoactive agent (OR 2.824, 95% CI 1.086-7.340) were independent risk factors for VI-AKI. The AUC of the nomogram validation cohorts were 0.807 (95% CI 0.785-0.846). The calibration curve revealed that the predicted outcome was in agreement with the actual observations. Finally, the DCA curves showed that the nomogram had a good clinical applicability value.

CONCLUSION

There are four independent risk factors for the occurrence of VI-AKI in overweight patients, and the nomogram prediction model has good predictive ability, which can provide reference for clinical decision-making.

Surgical-site infection in multifetal cesarean delivery

PURPOSE

The relationship between multifetal cesarean delivery and surgical-site infection (SSI) is unclear. If SSI is more common in multifetal cesareans, adjustment of practices such as antibiotic dosing could be warranted. The purpose of this study was to determine whether patients undergoing multifetal cesarean delivery are more likely to experience SSI than those undergoing singleton cesarean delivery.

METHODS

This was a retrospective cohort study including all cesarean deliveries at a tertiary hospital from 10/1/2009 to 12/28/2018. The primary outcome was rate of SSI in women after multifetal cesarean delivery as compared to those who underwent singleton cesarean delivery. Univariable analysis and multivariable logistic regression were used to assess independent clinical factors associated with SSI in multifetal cesarean deliveries.

RESULTS

34,340 women underwent cesarean delivery during this period. 33,211 were singletons (96.7%), and 1,129 were multifetal (3.3%). There was no difference in the rate of SSI in multifetal gestations (15/1,129, 1.3%) as compared to singletons (493/33,211, 1.5%) (p = 0.670, OR 0.89 [95% CI 0.53, 1.50], aOR 1.06 [95% CI 0.61, 1.84]). Limiting analysis to multifetal deliveries, prolonged rupture of membranes (p < 0.004, OR 5.43 [95% CI 1.49, 19.88]), labor augmentation (p < 0.001, OR 15.84 [1.74, 144.53]), and chorioamnionitis (p < 0.001, OR 15.43 [95% CI 3.11, 76.62]) were more common in women with SSI.

DISCUSSION

SSI is not increased in multifetal cesarean delivery as compared to singleton cesarean delivery. In multifetal cesareans, chorioamnionitis, prolonged rupture of membranes, and labor augmentation were associated with increased odds of SSI.

[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.

Associations between Polycystic Ovary Syndrome (PCOS) and Antibiotic Use: Results from the UAEHFS

Women with polycystic ovary syndrome (PCOS) have a higher susceptibility to infections compared to those without PCOS. Studies evaluating antibiotic use based on PCOS status are scarce. Therefore, we aimed to (i) assess the associations between self-reported PCOS and antibiotic use, and (ii) whether PCOS treatment and the age at PCOS diagnosis modified the associations above. This cross-sectional analysis used the United Arab Emirates Healthy Future Study (UAEHFS) conducted from February 2016 to March 2023 involving 2063 Emirati women aged 18-62 years. We performed ordinal logistic regressions under unadjusted and demographic-health-characteristic-adjusted models to obtain the odds ratios (ORs) and 95% confidence intervals (CIs) to analyze PCOS and antibiotic use. Subgroup analyses were performed by treatment status and age at diagnosis. We found that women with PCOS were 55% more likely to frequently take a course of antibiotics in the past year (aOR 1.55; 95% CI 1.26-1.90). Similar likelihoods were also found among those being treated for PCOS and those without treatment but with a PCOS diagnosis at ≤25 years. Our study suggests that PCOS was associated with an increased use of antibiotics among Emirati women. Understanding the frequent antibiotic use susceptibility among those with PCOS may improve antibiotic use surveillance and promote antibiotic stewardship in these at-risk individuals.

Therapeutic Drug Monitoring of Antimicrobials in Critically Ill Obese Patients

Obesity is a significant global public health concern that is associated with an elevated risk of comorbidities as well as severe postoperative and nosocomial infections. The treatment of infections in critically ill obese patients can be challenging because obesity affects the pharmacokinetics and pharmacodynamics of antibiotics, leading to an increased risk of antibiotic therapy failure and toxicity due to inappropriate dosages. Precision dosing of antibiotics using therapeutic drug monitoring may help to improve the management of this patient population. This narrative review outlines the pharmacokinetic and pharmacodynamic changes that result from obesity and provides a comprehensive critical review of the current available data on dosage adjustment of antibiotics in critically ill obese patients.

Intraosseous Vancomycin in Total Hip Arthroplasty - Superior Tissue Concentrations and Improved Efficiency

BACKGROUND

Literature shows that intraosseous (IO) infusions are capable of providing increased local concentrations compared to those administered via intravenous (IV) access. Successes while using the technique for antibiotic prophylaxis administration in total knee arthroplasty (TKA) prompted consideration for use in total hip arthroplasty (THA) however; no study exists for the use of IO vancomycin in THA.

METHODS

This single-blinded randomized control trial was performed from December 2020 to May 2022. Twenty patients were randomized into one of two groups: IV vancomycin (15 mg/kg) given routinely, or IO vancomycin (500mg/100cc of NS) injected into the greater trochanter during incision. Serum vancomycin levels were collected at incision and closure. Soft tissue vancomycin levels were taken from the gluteus maximus (at start and end of case), and acetabular pulvinar tissue. Bone vancomycin levels were taken from the femoral head, acetabular reamings, and intramedullary bone. Adverse local/systemic reactions, 30-day and 90-day complications were also tracked.

RESULTS

A statistically significant reduction in serum vancomycin levels was seen when comparing IO to IV vancomycin at both the start and end of the procedure. All local tissue samples had higher concentrations of vancomycin in the IO group. Statistically significant increases were present within the acetabular bone reamings, and approached significance in intramedullary femoral bone.

CONCLUSION

This study demonstrates the utility of IO vancomycin in primary THA with increased local tissue and decreased systemic concentrations. With positive findings in an area without tourniquet use, IO may be considered for antibiotic delivery for alternative procedures.

Impact of body size on efficacy of high-dose dual therapy for Helicobacter pylori eradication

BACKGROUND

High-dose dual therapy (HDDT) is an emerging and promising therapeutic regime for Helicobacter pylori (H. pylori) eradication. However, the pharmacokinetics of the components of HDDT, amoxicillin and proton pump inhibitor, are likely to be affected by body size. In this study, we aimed to find out the impact of body size on the efficacy of HDDT.

METHODS

We collected the medical data of 385 treatment-naive patients infected with H. pylori who received HDDT (esomeprazole 20 mg and amoxicillin 750 mg four times daily) for 14 days from July 2020 to December 2021. The associations among the eradication efficacy, adverse events, and variables (sex, age, height, body weight, body mass index (BMI), body surface area (BSA), smoking, drinking, etc.) were analyzed respectively in our study. Among these factors, continuous variables were classified into categorical variables using the cut-off values which were calculated by receiver operating characteristic analysis.

RESULTS

The eradication rate of HDDT was 89.9%. There were 55 (14.3%) patients who occurred adverse events during the treatment. Patients with height <170.5 cm, body weight <60.5 kg, BMI <20.55 kg/m² , BSA <1.69 m² had a higher eradication rate (92.1% vs. 84.0%, 93.1% vs. 86.8%, 96.0% vs. 87.8%, 93.4% vs. 84.8%, all p < .05). The multivariate analysis showed that BSA ≥1.69 m² (OR 2.53, 95% CI: 1.28-4.99, p = .007) was the only independent predictor of eradication failure.

CONCLUSION

HDDT could achieve better eradication efficacy in patients with small BSA. Clinicians should be aware of the impact of BSA on the H. pylori eradication rate and pay more attention to patients with large BSA.

Impact of guided weight-based medication dosing in pediatric patients with obesity

BACKGROUND

Obesity is a common disease state within pediatrics, with 19.7% of children in the United States classified as obese. Medication dosing in this population is a challenge not commonly examined in clinical drug trials. Dosing based on total body weight may not always be appropriate; therefore, ideal body weight (IBW) and adjusted body weight (AdjBW) may provide more effective dosing.

OBJECTIVE

The goal was to implement a dosing protocol for pediatric patients with obesity to improve adherence. The primary endpoint was to evaluate adherence to evidence-based dosing recommendations and the secondary endpoints included cost saving analysis for immune globulin and accurate charting of IBW and AdjBW.

METHODS

This was a single center, quality improvement project composed of pre- and post-implementation groups. An IBW and AdjBW calculator were implemented in our electronic health record, as customized enhancements, along with specific weight ordering options. A literature search of pharmacokinetic and pharmacodynamic dosing recommendations based on IBW and AdjBW was conducted. For both groups, patients were included if they were 3-18 years old, had a body mass index greater than or equal to the 95th percentile, and if they received a specified medication.

RESULTS

A total of 618 patients were identified with 24 and 56 patients included for the pre- and post-implementation groups. There were no statistically significant differences in baseline characteristics of the comparator groups. The usage of correct body weight increased from 1.2% to 24.2% after implementation and education (P < 0.001). Cost savings was analyzed for immune globulin with the potential for a net savings of $9423 ± 3626.92.

CONCLUSION

Dosing medications for our pediatric patients with obesity improved with the implementation of calculated dosing weights in the electronic health record, provision of an evidence-based dosing chart, and education of providers.

Ten-Day Vonoprazan-Amoxicillin Dual Therapy as a First-Line Treatment of Helicobacter pylori Infection Compared With Bismuth-Containing Quadruple Therapy

INTRODUCTION

No study has investigated the efficacy and safety of vonoprazan-amoxicillin dual therapy compared with bismuth quadruple therapy (B-quadruple). This study aimed to evaluate the efficacy and safety of 10-day vonoprazan-amoxicillin dual therapy as a first-line treatment of Helicobacter pylori infection compared with B-quadruple and to explore the optimal dosage of amoxicillin in the dual therapy.

METHODS

A total of 375 treatment-naive, H. pylori-infected subjects were randomly assigned in a 1:1:1 ratio into 3 regimen groups including VHA-dual (vonoprazan 20 mg twice/day + amoxicillin 750 mg 4 times/day), VA-dual (vonoprazan 20 mg + amoxicillin 1,000 mg twice/day), and B-quadruple (esomeprazole 20 mg + bismuth 200 mg + amoxicillin 1,000 mg + clarithromycin 500 mg twice/day). Eradication rates, adverse events (AEs), and compliance were compared between 3 groups.

RESULTS

The eradication rates of B-quadruple, VHA-dual, and VA-dual were 90.9%, 93.4%, and 85.1%, respectively, by per-protocol analysis; 89.4%, 92.7%, and 84.4%, respectively, by modified intention-to-treat analysis; 88.0%, 91.2%, and 82.4%, respectively, by intention-to-treat analysis. The efficacy of the VHA-dual group was not inferior to the B-quadruple group (P < 0.001), but VA-dual did not reach a noninferiority margin of -10%. The AEs rates of the B-quadruple group were significantly higher than those of the VHA-dual (P = 0.012) and VA-dual (P = 0.001) groups. There was no significant difference in medication compliance among 3 treatment groups (P = 0.995).

CONCLUSIONS

The 10-day VHA-dual therapy provided satisfactory eradication rates of >90%, lower AEs rates, and similar adherence compared with B-quadruple therapy as a first-line therapy for H. pylori infection. However, the efficacy of VA-dual therapy was not acceptable.

Evaluating linezolid dose regimens against methicillin-resistant Staphylococcus aureus based on renal function in populations with different body weight

WHAT IS KNOWN AND OBJECTIVE

Linezolid is an alternative first-line agent for MRSA pneumonia. This study assessed whether dose adjustments of linezolid against methicillin-resistant Staphylococcus aureus (MRSA) infections were needed based on renal function in populations with different body weight.

METHODS

Monte Carlo simulations were conducted to evaluate renal function in relation to the probability of target attainment (PTA) in three population groups with different body weight. Area under the concentration time curve (AUC)/ minimum inhibitory concentration (MIC) ratio and percentage of time above the MIC (%T > MIC) were regarded as pharmacokinetic/pharmacodynamic targets. The PTA and cumulative fractions of response (CFR) were calculated to assess the efficacy. Regarding safety, trough plasma concentration (C_min ) > 8 mg/L was used as target for toxicity.

RESULTS AND DISCUSSION

Using AUC/MIC >100 as the target pharmacodynamic (PD) index, the CFR of linezolid at the standard dose (600 mg every 12 h [q12h]) were 57.01%, 93.22%, and 99.93% in patients with normal renal function, patients with renal dysfunction and low body weight patients with renal dysfunction, respectively. Using 100%T > MIC as the target PD index, all the CFR of three population groups were more than 90% at the standard dose. The percentages of C_min  > 8 mg/L at the standard dose of linezolid were 24.16%, 53.24%, and 90.10% in three population groups on day 7.

WHAT IS NEW AND CONCLUSION

The risk of thrombocytopenia of linezolid was extremely higher in low body weight patients with renal impairment when receiving standard linezolid dose compared with patients with normal renal function. 450 mg q12h and 300 mg q12h might be effective and safe against MRSA infection in patients with renal dysfunction and low body weight patients with renal dysfunction, respectively.

Carol Davila Central Military Emergency University Hospital, 010825 Bucharest, Romania, Torsin LI, Filimon CR, Tănase NV, Moisă E, Negoiță SI, Clinic of Anaesthesia and Intensive Care Medicine, Dr. Carol Davila Central Military Emergency University Hospital, 010825 Bucharest, Romania, Clinic of Anaesthesia and Intensive Care Medicine, Dr. Carol Davila Central Military Emergency University Hospital, 010825 Bucharest, Romania, Department of Anaesthesia and Intensive Care Medicine, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania 2 Clinic of Anaesthesia and Intensive Care Medicine, Dr. Carol Davila Central Military Emergency University Hospital, 010825 Bucharest, Romania, "Department of Anaesthesia and Intensive Care Medicine, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania, 3 Clinic of Anaesthesia and Intensive Care Medicine, Elias Emergency University Hospital, 011461 Bucharest, Romania", Department of Anaesthesia and Intensive Care Medicine, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania, 3 Clinic of Anaesthesia and Intensive Care Medicine, Elias. Individualized surgical antibiotic prophylaxis – why, when, and how?

"Surgical site infections (SSI) greatly concern clinicians, as they are associated with significant morbidity and mortality, prolonged hospitalization, and costs. Antibiotic prophylaxis plays a pivotal role among the procedures that are usually employed for the prevention of surgical-related infections. This narrative review aims to cover some of the particular situations when the clinician might consider individualizing antibiotic prophylaxis for a patient. With the rising incidence of multi-drug resistant bacteria carriage among not only hospitalized or institutionalized patients but also patients from the community, there might be a tendency to use extended-spectrum antibiotics for longer periods for surgical infection prevention. However, the inappropriate use of antibiotics increases the selection pressure, thus favoring the spreading of resistant bacteria. Moreover, specific patient characteristics or pathologies might need to be considered to customize the type, dose, or length of administration of an antibiotic as surgical prophylaxis. Using prosthetic material or prolonged surgeries with large fluid shifts are other situations when individualized antibiotic prophylaxis might be thought of. Keeping in mind that it is of utmost importance that everyone adheres to the current guidelines for surgical antibiotic prophylaxis, customization of local protocols according to well-thought-out strategies might prove beneficial in SSI prevention."

Cefazolin prophylaxis in spine surgery: patients are frequently underdosed and at increased risk for infection

BACKGROUND CONTEXT

Perioperative antibiotics are critical in reducing the risk of postoperative spine infections. However, the efficacy and optimal weight-based prophylactic cefazolin dosing is unclear.

PURPOSE

To determine (1) if inadequate weight-based prophylactic dosing of cefazolin affects infection rates after spinal fusions, and (2) identify the optimal dosing of cefazolin.

STUDY DESIGN/SETTING

Single center retrospective cohort PATIENT SAMPLE: Patients undergoing posterior cervical or lumbar spinal fusion between January 2000 and October 2020 OUTCOME MEASURES: Postoperative surgical site infection status METHODS: Patients were grouped based on our institutionally derived dosing adequacy standards, 1 g for <60 kg, 2 g for 60 to 120 kg, and 3 g for >120 kg. Univariate comparisons and multivariate regressions identified the effect of inadequate dosing on infection rate. Patients were subsequently regrouped into cefazolin dose (grams) administered and logistic regression and receiver operating characteristic curves were compiled to determine the probability of infection based on cefazolin dose and patient weight. Alpha was set at 0.05.

RESULTS

A total of 2,643 patients met inclusion criteria and 95 infections (3.6%) were identified. The infection rate was higher in the inadequate dosing group (5.86% vs. 2.58%, p<.001). Adequate dosing was a predictor of decreased infections after lumbar fusion (OR: 0.43, p<.001), but not posterior cervical fusions (OR: 0.47, p=.065). Patients were subsequently regrouped into 1 g or 2 g of cefazolin administered resulting in a 5.01% and 2.77% infection rate, respectively (p=.005). The area under the curve (AUC) and 95% confidence interval for one (0.850 [0.777-0.924]) and two (0.575 [0.493-0.657]) g of cefazolin demonstrated lower infection rates for patients given 2 g cefazolin.

CONCLUSIONS

Patients receiving an inadequate weight-based dose of preoperative cefazolin had an increased risk of infection following spinal fusion surgery. Two grams prophylactic cefazolin significantly reduces the likelihood of infection.

Optimizing Antimicrobial Therapy by Integrating Multi-Omics With Pharmacokinetic/Pharmacodynamic Models and Precision Dosing

In the era of “Bad Bugs, No Drugs,” optimizing antibiotic therapy against multi-drug resistant (MDR) pathogens is crucial. Mathematical modelling has been employed to further optimize dosing regimens. These models include mechanism-based PK/PD models, systems-based models, quantitative systems pharmacology (QSP) and population PK models. Quantitative systems pharmacology has significant potential in precision antimicrobial chemotherapy in the clinic. Population PK models have been employed in model-informed precision dosing (MIPD). Several antibiotics require close monitoring and dose adjustments in order to ensure optimal outcomes in patients with infectious diseases. Success or failure of antibiotic therapy is dependent on the patient, antibiotic and bacterium. For some drugs, treatment responses vary greatly between individuals due to genotype and disease characteristics. Thus, for these drugs, tailored dosing is required for successful therapy. With antibiotics, inappropriate dosing such as insufficient dosing may put patients at risk of therapeutic failure which could lead to mortality. Conversely, doses that are too high could lead to toxicities. Hence, precision dosing which customizes doses to individual patients is crucial for antibiotics especially those with a narrow therapeutic index. In this review, we discuss the various strategies in optimizing antimicrobial therapy to address the challenges in the management of infectious diseases and delivering personalized therapy.

[The effectiveness of eradication therapy of the 1st line of Helicobacter pylori infection in patients with type 2 diabetes mellitus]

AIM

Evaluation of the efficacy and safety of eradication therapy of infection Helicobacter pylori in patients with H. pylori- associated pathology of the upper gastrointestinal tract and concomitant type 2 diabetes mellitus (DM).

MATERIALS AND METHODS

The prospective randomized study involving 180 patients (87 men and 93 women) with H. pylori- associated pathology of the upper gastrointestinal tract was carried out. The patients were divided into four groups of 45 people: 1 patients without diabetes who received the classic triple eradication therapy; 2 patients with type 2 DM who received the classic triple eradication therapy; 3 patients without DM who underwent quadrotherapy with bismuth preparations; 4 patients with type 2 DM who underwent quadrotherapy with bismuth preparations. Eradication therapy was carried out for 14 days. Evaluation of the effectiveness of eradication using a breath test was carried out 4 weeks after completion of the course of treatment. Eradication success was assessed separately for ITT and PP analyzes.

RESULTS

The effectiveness of classical triple eradication therapy in patients with concomitant type 2 DM is 64.4% in the ITT group and 69.05% in the PP: quadrotherapy 73.34 and 80.49%, respectively. The effectiveness of first line eradication therapy is higher in patients without DM compared with groups of patients with concomitant type 2 DM: ITT 83.33%, PP 88.23% and ITT 68.89%, PP 74.70%, respectively. The incidence of side effects in patients with type 2 DM: with the use of classical triple therapy 22.23%, quadrotherapy 31.12%.

CONCLUSION

The data of the study of the efficacy and safety of line I eradication therapy make it possible to recommend the four-component therapy based on bismuth for use in clinical practice, especially in patients with DM.

A prospective study of filgrastim pharmacokinetics in morbidly obese patients compared with non-obese controls

INTRODUCTION

Filgrastim is a human granulocyte colony-stimulating factor (G-CSF). There are limited data on dosing filgrastim in obesity. The objective of this study was to compare filgrastim pharmacokinetic parameters for morbidly obese and non-obese patients after a single subcutaneous dose of filgrastim dosed per actual body weight.

METHODS

This prospective, matched-pair study (NCT01719432) included patients ≥18 years of age, receiving filgrastim at 5 μg/kg with a weight >190% of their ideal body weight (IBW) for "morbidly obese" patients or within 80%-124% of IBW for matched-control patients. The control group was prospectively matched for age (within 10 years), degree of neutropenia, and gender. Filgrastim doses were not rounded to vial size, to allow more accurate assessment of exposure. Blood samples were collected at 0 (prior to dose), 2, 4, 6, 8, 12, and 24 h after the first subcutaneous administration of filgrastim.

RESULTS

A total of 30 patients were enrolled in this prospective pharmacokinetic study, with 15 patients assigned to each arm. Non-compartmental analysis showed that the systemic clearance (Cl) was 0.111 ± 0.041 ml/min in the morbidly obese group versus 0.124 ± 0.045 ml/min in the non-obese group (p = 0.44). Additionally, the mean area under the curve (AUC_0-24h ) was 49.3 ± 13.9 ng/ml × min in the morbidly obese group versus 46.3 ± 16.8 ng/mL x min in the non-obese group (p = 0.6). No differences were seen in maximum concentrations (C_max ) between the two groups (morbidly obese: 48.1 ± 14.7 ng/ml vs. non-obese: 49.2 ± 20.7 ng/ml (p = 0.87)). The morbidly obese group had a numerically higher, but not statistically significant, increase in time to maximum concentration (T_max ) compared to the non-obese group (544 ± 145 min vs 436 ± 156 min (p = 0.06), respectively).

CONCLUSION

Calculating subcutaneous filgrastim doses using actual body weight appears to produce similar systemic exposure in morbidly obese and non-obese patients with severe neutropenia.

Gentamicin Alone Is Inadequate to Eradicate Neisseria Gonorrhoeae From the Pharynx

BACKGROUND

Centers for Disease Control and Prevention (CDC) guidelines recommend 240 mg gentamicin plus 2 g azithromycin for the treatment of gonorrhea in cephalosporin-allergic patients. The efficacy of gentamicin alone in the treatment of pharyngeal gonorrhea is uncertain.

METHODS

Between September 2018 and March 2019, we enrolled men who have sex with men with nucleic acid amplification test-diagnosed pharyngeal gonorrhea in a single-arm, unblinded clinical trial. Men received a single 360-mg intramuscular dose of gentamicin and underwent test of cure by culture 4-7 days later. The study measured creatinine at enrollment and test of cure, serum gentamicin concentration postdose to establish peak concentration (Cmax), and standard antimicrobial minimum inhibitory concentrations (MICs) by agar dilution. The trial was designed to establish a point estimate for gentamicin's efficacy for pharyngeal gonorrhea. We planned to enroll 50 evaluable participants; assuming gentamicin was 80% efficacious, the trial would establish a 95% confidence interval (CI) of 66%-90%. We planned interim analyses at n = 10 and n = 25.

RESULTS

The study was stopped early due to poor efficacy. Of 13 enrolled men, 10 were evaluable, and only 2 (20% [95% CI, 2.5%-55.6%]) were cured. Efficacy was not associated with gentamicin Cmax or MIC. No participants experienced renal insufficiency. The mean creatinine percentage change was +5.2% (range, -6.7% to 21.3%). Six (46%) participants experienced headache, all deemed unrelated to treatment.

CONCLUSIONS

Gentamicin alone failed to eradicate Neisseria gonorrhoeae from the pharynx. Clinicians should use caution when treating gonorrhea with the CDC's current alternative regimen (gentamicin 240 mg plus azithromycin 2 g) given increases in azithromycin resistance and gentamicin's poor efficacy at the pharynx.

CLINICAL TRIALS REGISTRATION

NCT03632109.

Safety and efficacy of omadacycline by BMI categories and diabetes history in two Phase III randomized studies of patients with acute bacterial skin and skin structure infections

OBJECTIVES

The objectives of this post-hoc analysis were to examine the safety and efficacy of omadacycline by BMI categories and diabetes history in adults with acute bacterial skin and skin structure infections (ABSSSI) from two pivotal Phase III studies.

PATIENTS AND METHODS

OASIS-1 (ClinicalTrials.gov identifier NCT02378480): patients were randomized 1:1 to IV omadacycline or linezolid for 7-14 days, with optional transition to oral medication. OASIS-2 (ClinicalTrials.gov identifier NCT02877927): patients received once-daily oral omadacycline or twice-daily oral linezolid for 7-14 days. Early clinical response (ECR) was defined as ≥20% reduction in lesion size 48-72 h after the first dose. Clinical success at post-treatment evaluation (PTE; 7-14 days after the last dose) was defined as symptom resolution such that antibacterial therapy was unnecessary. Safety was assessed by treatment-emergent adverse events and laboratory measures. Between-treatment comparisons were made with regard to WHO BMI categories and diabetes history.

RESULTS

Patients were evenly distributed among healthy weight, overweight and obese groups. Clinical success for omadacycline-treated patients at ECR and PTE was similar across BMI categories. Outcomes by diabetes status were similar in omadacycline- and linezolid-treated patients: at ECR, clinical success rates were lower for those with diabetes; at PTE, clinical success was similar between treatment groups regardless of diabetes history. The safety of omadacycline and linezolid was largely similar across BMI groups and by diabetes history.

CONCLUSIONS

Omadacycline efficacy in patients with higher BMI and in patients with diabetes was consistent with results from two pivotal Phase III ABSSSI trials. Fixed-dose omadacycline is an appropriate treatment for ABSSSI in adults regardless of BMI.

Impact of body size on first-line Helicobacter pylori eradication success using vonoprazan and amoxicillin dual therapy

BACKGROUND

As a first-line therapy for Helicobacter pylori, dual therapy with vonoprazan and amoxicillin (VA-dual) provides an eradication rate similar to that of vonoprazan-based triple therapy. As the factors associated with the eradication rate of H. pylori with VA-dual are unknown,we investigated them in this study.

MATERIALS AND METHODS

Overall, 163 patients diagnosed with H. pylori infection received VA-dual (vonoprazan 20 mg twice daily and amoxicillin 750 mg twice daily for 7 d). The association between successful H. pylori eradication and the following patient clinical factors was analyzed: sex, age, height, weight, body surface area (BSA), body mass index (BMI), history of early gastric carcinoma and peptic ulcer, comorbidity of cirrhosis, alcohol consumption habit, smoking habit, common use of proton pump inhibitors, and concomitant use of drugs that are substratesof cytochrome P450 (CYP) 3A4. The association between post-eradication adverse events and clinical factors was analyzed retrospectively.

RESULTS

Successful H. pylori eradication was associated with a lower BSA (eradication rate: 90.8% in patients with BSA <1.723 vs. 79.6% in those with BSA ≥1.723; p = 0.045). The incidence of adverse events was higher in women than in men (adverse events: 40.0% in women vs. 19.4% in men; p = 0.004).

CONCLUSIONS

Successful H. pylori eradication with VA-dual was associated with the small body size of patients. This therapy may have to be adjusted per body size.

Drug dosing in the critically ill obese patient: a focus on medications for hemodynamic support and prophylaxis

Medications used for supportive care or prophylaxis constitute a significant portion of drug utilization in the intensive care unit. Evidence-based guidelines are available for many aspects of supportive care but drug doses listed are typically for patients with normal body habitus and not morbid obesity. Failure to account for the pharmacokinetic changes that occur with obesity can lead to an incorrect dose and treatment failure or toxicity. This paper is intended to help clinicians design initial dosing regimens in critically ill obese patients for medications commonly used for hemodynamic support or prophylaxis. A detailed literature search of medications used for supportive care or prophylaxis listed in practice guidelines was conducted with an emphasis on obesity, pharmacokinetics and dosing. Relevant manuscripts were reviewed and strategies for dosing are provided. For medications used for hemodynamic support, a similar strategy can be used as in non-obese patients. Similarly, medications for stress ulcer prophylaxis do not need to be adjusted. Anticoagulants for venous thromboembolism prophylaxis, on the other hand, require an individualized approach where higher doses are necessary.

Impact of Obesity on Surgical Outcomes of Laparoscopic Appendectomy: Lessons Learned From 2000 Cases in an Urban Teaching Hospital

BACKGROUND

As the prevalence of obesity continues to increase worldwide, we aimed to determine the surgical outcomes of obese patients with acute appendicitis undergoing laparoscopic appendectomy (LA).

MATERIALS AND METHODS

A retrospective analysis of patients undergoing LA during the period 2006 to 2019 was performed. The cohort was divided into 2 groups: G1, patients with body mass index ≥30 kg/m2 and G2: patients with body mass index <30 kg/m2.

RESULTS

A total of 2009 LA were performed; 114 (6%) were included in G1 and 1895 (94%) in G2. Complicated acute appendicitis rate (G1: 39% vs. G2: 20%, P<0.0001), conversion rates (G1: 12% vs. 1.69%, P<0.0001), overall 30-day morbidity rates (G1: 27% vs. G2: 14%, P=0.0001), and postoperative intra-abdominal abscess rates (G1: 8% vs. (2%), P<0.0001) were higher in obese patients. Furthermore, obesity was an independent risk factor for overall morbidity, postoperative intra-abdominal abscess, and conversion to open surgery.

CONCLUSION

In obese patients, LA had inferior clinical outcomes compared with nonobese patients.

Evaluation of Linezolid Pharmacokinetics in Critically Ill Obese Patients with Severe Skin and Soft Tissue Infections

Linezolid standard dosing is fixed at 600 mg every 12 h (q12h) for adults. Literature suggests critically ill, obese patients require higher doses. The study aim is 2-fold: (i) to describe linezolid pharmacokinetics (PK), and (ii) to evaluate if PK/pharmacodynamic (PD) target attainment is achieved with standard dosing in critically ill, obese patients with severe skin and soft tissue infections (SSTIs). Adult patients with a body mass index (BMI) of ≥30 kg/m² and receiving intravenous (i.v.) linezolid from August 2018 to April 2019 were eligible for consent in this prospective study. Severe SSTIs were defined as necrotizing fasciitis, myonecrosis, or SSTI with sepsis syndrome. Four blood samples were collected at steady state at 1, 3, 5 h postinfusion and as a trough. Target attainment was defined as achieving area under the concentration-time curve from 0 to 24 h to MIC (AUC_0-24h/MIC) of ≥100 h*mg/liter. Monte Carlo simulations were used to determine the probability of target attainment (PTA). Eleven patients were included in the study. The median BMI was 45.7 kg/m², and median total body weight (TBW) was 136.0 kg. Seven patients received standard linezolid doses, and four received 600 mg q8h. A one-compartment model described linezolid PK. Based on AUC_0-24h/MIC targets, for noncirrhotic patients at 140 kg, the PTA with standard linezolid doses was 100%, 98.8%, 34.1%, and 0% for MICs of 0.5, 1, 2, and 4 mg/liter, respectively. In conclusion, target attainment of ≥90% is not achieved with standard linezolid doses for noncirrhotic patients ≥140 kg with MICs of ≥2 mg/liter. This study adds to accumulating evidence that standard linezolid doses may not be adequate for all patients.

Efficacy and Safety of Eravacycline in Obese Patients: A Post Hoc Analysis of Pooled Data From the IGNITE1 and IGNITE4 Clinical Trials

Background

The increasing prevalence of obesity worldwide merits an examination of the efficacy and safety profiles of agents dosed by weight.

Methods

Data for patients (n = 1037) were obtained from the pooled IGNITE1 and IGNITE4 randomized double-blind trials in which patients with complicated intra-abdominal infections received eravacycline 1 mg/kg (actual body weight [ABW]) every 12 hours or comparator (ertapenem 1 g every 24 hours or meropenem 1 g every 8 hours) intravenously. This post hoc analysis evaluated clinical cure rates, adverse events, and drug discontinuation rates stratified by body mass index (BMI) categories of BMI >40 kg/m² (Obese, Class III), BMI 35–39.9 kg/m² (Obese, Class II), BMI 30–34.9 kg/m² (Obese, Class I), BMI 25–29.9 kg/m² (Overweight), BMI 18.5–24.9 kg/m² (Healthy weight), and BMI <18.5 kg/m² (Underweight).

Results

Clinical cure rates were high across BMI categories and ranged from 82% to 94% in the eravacycline group and 88.5%–100% in the comparator group. Similar cure rates were observed among eravacycline-treated healthy weight (126/134; 94%), overweight (127/146; 87%), and obese (BMI ≥30 kg/m²; 110/129; 85.3%) patients. In the comparator group, a similar proportion of patients demonstrated clinical response (healthy weight [132/145; 91%], overweight [130/144; 90.3%], and obese [115/129; 89.1%]). Of the treatment-emergent adverse events that occurred in eravacycline-treated obese patients, a larger proportion were gastrointestinal-related (ie, nausea and vomiting); however, discontinuation rates were low and similar between eravacycline and carbapenems.

Conclusions

This post hoc analysis demonstrates the therapeutic utility and acceptable safety profile of eravacycline dosed by ABW in obese patients (BMI ≥30 kg/m²).

Dosing Common Medications in Hospitalized Pediatric Patients with Obesity: A Review

Medication management in children and adolescents with obesity is challenging because both developmental and pathophysiological changes may impact drug disposition and response. Evidence to date indicates an effect of obesity on drug disposition for certain drugs used in this population. This work identified published studies evaluating drug dosing, pharmacokinetics (PK), and effect in pediatric patients with obesity, focusing on 70 common medications used in a pediatric network of 42 US medical centers. A PubMed search revealed 33 studies providing PK and/or effectiveness data for 23% (16 of 70) of medications, 44% of which have just one study and can be considered exploratory. This work appraising 4 decades of literature shows several promising approaches: greater use of PK models applied to prospective clinical studies, dosing recommendations derived from both PK and safety, and multiyear effectiveness data on drugs for chronic conditions (e.g., asthma). Most studies make dose recommendations but are weakened by retrospective study design, small study populations, and no controls or historic controls. Dosing decisions continue to rely on extrapolating knowledge, including targeting systemic drug exposure typically achieved in adults. Optimal weight-based dosing strategies vary by drug and warrant prospective, controlled studies incorporating PK and modeling and simulation to complement clinical assessment.

Successful Treatment of Delayed Methotrexate Clearance Using Glucarpidase Dosed on Ideal Body Weight in Obese Patients

Delayed methotrexate (MTX) elimination after treatment with high-dose (HD) MTX may result in life-threatening toxicities as well as acute kidney injury (AKI). Treatment includes administration of glucarpidase, an enzyme that rapidly inactivates MTX. Dosing of glucarpidase is based on body weight; however, recommendations for dosage adjustments in obese patients are lacking. We describe three obese adult patients (body mass index [BMI] range 31-43 kg/m² ) who received HD-MTX following all precautions for its treatment. Although peak MTX concentrations were within the expected range (308-368 µmol/L), MTX concentrations after 24 hours or later were markedly increased (97, 52, and 19 µmol/L, respectively). Two patients experienced AKI. After a single intravenous dose of glucarpidase 4000 units (50 units/kg on the basis of ideal body weight [IBW]) was administered to each patient 38, 46, and 60 hours, respectively, after the start of MTX, MTX concentrations dropped quickly to 1.37, 0.07, and 0.03 µmol/L, respectively, and further decreased steadily. Over time, clinical status and renal function improved in all patients. Glucarpidase is a highly hydrophilic molecule with a volume of distribution of 3.6 L, representing the intravascular volume of an adult. Therefore, we used IBW for glucarpidase dose calculations, allowing us to reduce the dose that would have been determined by using total body weight. This approach resulted in a rapid decrease of MTX serum concentrations and may reduce treatment costs of this highly expensive drug.

Calculated initial parenteral treatment of bacterial infections: Pharmacokinetics and pharmacodynamics

This is the third chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. The chapter features the pharmacokinetic and pharmacodynamics properties of the most frequently used antiinfective agents.

Vancomycin Dosing in Children With Overweight or Obesity: A Systematic Review and Meta-analysis

CONTEXT

Vancomycin is a medication with potential for significant harm with both overdosing and underdosing. Obesity may affect vancomycin pharmacokinetics and is increasingly common among children.

OBJECTIVE

We aimed to determine if children with overweight or obesity have increased vancomycin trough concentrations with total body weight (TBW) dosing compared with children with normal weight.

DATA SOURCES

We conducted a search of Medline and Medline In-Process & Other Non-Indexed Citations from 1952 (the year vancomycin was discovered) to November 2017.

STUDY SELECTION

Search terms included vancomycin, body weight, and body composition terms and were limited to children. Studies were reviewed and screened by ≥2 reviewers.

DATA EXTRACTION

The primary outcome was vancomycin level. Data were extracted by 2 reviewers. We performed quality assessment using the Newcastle-Ottawa quality assessment scale.

RESULTS

We identified 271 records. After abstract and full-text screening, we identified 7 studies for full review. Six of the 7 studies used a matched case-control design, although there was significant variation in study methodology. Four of the 7 studies were included in a meta-analysis, which revealed a small but significant difference in vancomycin trough levels between children with normal weight and children with overweight or obesity when dosed by using TBW (N = 521; mean difference 2.2 U [95% confidence interval: 1.0-3.4]).

CONCLUSIONS

High-quality data to guide vancomycin dosing in children with obesity are lacking. More studies evaluating dosing strategies in children with obesity are warranted because using TBW to dose vancomycin may lead to higher vancomycin concentrations and potential toxicity.

Modern pharmacological treatment of obese patients

There are many angles to consider in drug treatment of obese patients. On the one hand, some specific weight loss drugs are available, on the other, several drugs are associated with unintentional weight changes. When treating an obese patient for any given disease, several physiological changes may influence the pharmacokinetic properties of the drugs required. Thus, increased body weight may influence the efficacy and safety of some drug treatments. Even more complicated is the situation after weight reduction surgery. Due to the various changes to the gastrointestinal tract induced by the different surgical techniques used, and the dynamic changes in body composition thereafter, drug dosing has to be constantly reconsidered. Whereas all of these issues are of clinical importance, none of them have been investigated in the necessary depth and broadness to ensure safe and efficacious drug treatment of the massively obese patient. Individual considerations have to be based on comorbidities, concomitant medication, and on specific drug properties, for example, lipophilicity, volume of distribution, and metabolism. In this article we summarize the data available on different aspects of drug treatment in the obese patient with the hope of improving patient care.

PK/PD targets of amikacin and gentamicin in ICU patients

OBJECTIVES

We aimed to evaluate the probability to achieve PK-PD targets in patients with sepsis hospitalized in the intensive care unit (ICU) after a single dose of 30mg/kg of amikacin or 8mg/kg of gentamicin.

PATIENTS AND METHODS

This single-center prospective study included 138 ICU patients with severe sepsis or septic shock with an indication for intravenous amikacin (N=89) or gentamicin (N=49). Maximum concentration (C_max) was measured 30 minutes after infusion completion. PK/PD objectives were respectively C_max≥60mg/L and ≥30mg/L for amikacin and gentamicin for empirical therapy, and a C_max/MIC ratio≥8, as per French guidelines.

RESULTS

The median Simplified Acute Physiology Score II was 43 and ICU case fatality rate was 34.8%. A causative bacterial agent was identified in 94 patients (68.1%). Three pathogens had acquired aminoglycoside resistance and 15 were naturally resistant. The targeted C_max for the first dose was achieved in 53 patients (59.6%) receiving amikacin, and one (2.2%) patient receiving gentamicin. C_max/MIC ratio≥8 was obtained in all patients infected with susceptible pathogens (N=72). Factors associated with C_max≥60mg/L of amikacin in multivariate analysis were dose per kg of adapted body weight (OR=1.39, P<0.001) and renal clearance estimated with CKD-EPI formula (OR=0.98, P=0.003).

CONCLUSIONS

Despite high doses, amikacin and gentamicin first C_max remain dramatically low in ICU patients. However, an adequate C_max/MIC ratio was reached in all patients.

Self-reported adverse drug effects and associated factors among H. pylori infected patients on standard triple therapy: Prospective follow up study

Background

One of the most common reasons for poor medication adherence and associated treatment failure of triple therapy is adverse drug effect (ADEs) of medications.

Objective

Assessment of ADEs and associated factors during H. pylori eradication therapy.

Method

Consented H. pylori positive adult outpatients on standard triple therapy (proton pump inhibitor, amoxicillin and clarithromycin) were involved in this facility based follow up study from May 2016 to April 2018 at Bahir Dar city in Ethiopia. Pre-developed questionnaire and formats were used to collect sociodemographic, medical information, and patient practice data before, during, and after therapy. Bivariate and backward stepwise multivariate logistic regression was used to analyze data. P-value < 0.05 at 95%CI was considered as significant.

Result

A total of 421 patients were involved in the study. Almost 80% of the patients were urban residents. Mean (±SD) age and body weight of patients were 30.63 (± 10.74) years and 56.79 (± 10.17) kg, respectively. ADE was reported from 26.1% of the patients and of all the reported ADEs, more than 85% was manifested with gastrointestinal symptoms which include gastrointestinal discomfort(39.1%), nausea (13.6%), constipation(12.7%), diarrhea(12.9%) and anorexia(10%). Determinants of self-reported ADEs among patients in the present study were body mass index above 25 (AOR: 2.55; 95%CI (1.21–5.38), p = 0.014), duration of acid-pepsin disorder more than 3weeks (AOR: 3.57; 95%CI (1.63–7.81), p = 0.001), pain feeling during long interval between meals (AOR: 2.14; 95%CI (1.19–3.84), p = 0.011), and residence in urban area (AOR: 1.95; 95% CI (1.04–3.67), p = 0.038).

Conclusion

Significant proportion of patients reported ADEs which commonly manifested with gastrointestinal symptoms. Consideration of patients’ body mass index, duration of the disorder, period of the day when patients feel pain, and patients’ area of residence could help to reduce ADEs experienced during H. pylori eradication therapy.

Association Between Estimated Pharmacokinetic/Pharmacodynamic Predictions of Efficacy and Observed Clinical Outcomes in Obese and Nonobese Patients With Enterobacteriaceae Bloodstream Infections

Background

Evidence on pharmacokinetic/pharmacodynamic (PK/PD) alterations and clinical outcomes in obese patients with serious infections remains limited. This study aimed to evaluate predicted PK/PD indices of efficacy and observed clinical outcomes between obese and nonobese patients receiving cefepime or piperacillin-tazobactam for Enterobacteriaceae bacteremia.

Methods

This was a retrospective study of adult inpatients from 1/2012 to 9/2015 with Enterobacteriaceae bacteremia who received empiric cefepime or piperacillin-tazobactam. The primary outcome was clinical cure. First-dose free-drug exposure was estimated via predicted concentrations generated from population PK analyses and used to assess PD target attainment (>50% fT > minimum inhibitory concentration [MIC]) for the specific Enterobacteriaceae isolate. Multivariable logistic regression was utilized to identify independent predictors of clinical cure.

Results

One hundred forty-two patients were included, 57 obese and 85 nonobese. Clinical cure was achieved in 68.4% of obese and 62.4% of nonobese patients (P = .458). No significant difference in outcomes was observed when evaluated by World Health Organization (WHO) obesity classes. The PK/PD target was achieved in 98.2% of obese and 91.8% of nonobese patients (P = .144). Independent predictors of clinical cure were immunosuppression and a shorter duration of bacteremia. Obesity was not identified as a significant predictor of clinical outcomes.

Conclusions

Neither predicted PK/PD parameters nor clinical outcomes differed significantly between obese and nonobese patients treated with piperacillin-tazobactam or cefepime. As the majority of patients received extended-infusion piperacillin-tazobactam for bacteremia due to pathogens with low MICs, the potentially detrimental pathophysiologic derangements caused by obesity may not have been realized. Further studies are warranted to establish the optimal treatment of serious infections in obese patients.

Helicobacter pylori eradication rate of standard triple therapy and factors affecting eradication rate at Bahir Dar city administration, Northwest Ethiopia: A prospective follow up study

BACKGROUND

Eradication of Helicobacter pylori infection with standard triple therapy has been accepted to curb associated risks of chronic gastritis andpeptic ulcer disease.

OBJECTIVE

To assess H. pylori eradication rate of standard triple therapy and patient related factors affecting eradication rate.

METHODS

A facility based prospective follow up study was conducted in Bahir Dar City Administration, Ethiopia, on consented outpatients presented with gastritis and peptic ulcer disease and positive for H. pylori stool antigen test from May 2016 to April 2018. Eradication was confirmed with stool antigen test made after 4-6 weeks of standard triple therapy, comprising of proton pump inhibitor, clarithromycin and amoxicillin. Pre-developed questionnaire and data collection formats were used to collect variables before and after therapy. Bivariate and backward stepwise multivariate logistic regression was used to analyze data. P-value < 0.05 at 95%CI was considered as significant.

RESULTS

The overall H. pylori eradication rate was 90.3% (379/421). Almost 80% of the patients were urban residents. Mean (±SD) age and body weight of patients were 30.63 (± 10.74) years and 56.79 (± 10.17) kg, respectively. Self-reported adverse drug effects and area of residence of patients were factors affecting eradication rate significantly. Patients with no self-reported adverse drug effect were 3.85 (AOR: 3.85; 95%CI (1.41-5.26)) times more likely to eradicate H. pylori infection compared to those reported adverse effects. Patients living in rural area were 2.7 (AOR: 2.7; 95%CI (1.19-20.0)) times more likely to achieve eradication compared to urban residents.

CONCLUSION

H. pylori eradication rate is within the recommended level for clinical practice, indicating that modifications of the standard triple therapy observed in the different healthcare institutions are not evidence-based. Emphasis should be given to adverse drug effects of medications and tailored counseling based on area of residence could have a contribution in improving eradication rate.

Tobramycin Clearance Is Best Described by Renal Function Estimates in Obese and Non-obese Individuals: Results of a Prospective Rich Sampling Pharmacokinetic Study

Purpose

Tobramycin is an aminoglycoside antibiotic of which the 24 h exposure correlates with efficacy. Recently, we found that clearance of the aminoglycoside gentamicin correlates with total body weight (TBW). In this study, we investigate the full pharmacokinetic profile of tobramycin in obese and non-obese individuals with normal renal function.

Methods

Morbidly obese individuals (n = 20) undergoing bariatric surgery and non-obese healthy volunteers (n = 8), with TBW ranging 57–194 kg, received an IV dose of tobramycin with plasma concentrations measured over 24 h (n = 10 per individual). Statistical analysis, modelling and simulations were performed using NONMEM.

Results

In a two-compartment model, TBW was the best predictor for central volume of distribution (p < 0.001). For clearance, MDRD (de-indexed for body surface area) was identified as best covariate (p < 0.001), and was superior over TBW ((p < 0.05). Other renal function estimates (24 h urine GFR and de-indexed CKD-EPI) led to similar results as MDRD (all p < 0.001)).

Conclusions

In obese and non-obese individuals with normal renal function, renal function estimates such as MDRD were identified as best predictors for tobramycin clearance, which may imply that other processes are involved in clearance of tobramycin versus gentamicin. To ensure similar exposure across body weights, we propose a MDRD-based dosing nomogram for obese patients.

Electronic supplementary material

The online version of this article (10.1007/s11095-019-2651-2) contains supplementary material, which is available to authorized users.

Assessment of Body Composition in Health and Disease Using Bioelectrical Impedance Analysis (BIA) and Dual Energy X-Ray Absorptiometry (DXA): A Critical Overview

The measurement of body composition (BC) represents a valuable tool to assess nutritional status in health and disease. The most used methods to evaluate BC in the clinical practice are based on bicompartment models and measure, directly or indirectly, fat mass (FM) and fat-free mass (FFM). Bioelectrical impedance analysis (BIA) and dual energy X-ray absorptiometry (DXA) (nowadays considered as the reference technique in clinical practice) are extensively used in epidemiological (mainly BIA) and clinical (mainly DXA) settings to evaluate BC. DXA is primarily used for the measurements of bone mineral content (BMC) and density to assess bone health and diagnose osteoporosis in defined anatomical regions (femur and spine). However, total body DXA scans are used to derive a three-compartment BC model, including BMC, FM, and FFM. Both these methods feature some limitations: the accuracy of BIA measurements is reduced when specific predictive equations and standardized measurement protocols are not utilized whereas the limitations of DXA are the safety of repeated measurements (no more than two body scans per year are currently advised), cost, and technical expertise. This review aims to provide useful insights mostly into the use of BC methods in prevention and clinical practice (ambulatory or bedridden patients). We believe that it will stimulate a discussion on the topic and reinvigorate the crucial role of BC evaluation in diagnostic and clinical investigation protocols.

Analysis of Pooled Phase III Efficacy Data for Delafloxacin in Acute Bacterial Skin and Skin Structure Infections

BACKGROUND

Delafloxacin is an oral or intravenous (IV) antibiotic indicated for the treatment of acute bacterial skin and skin structure infections (ABSSSI), including both gram-positive (including methicillin-resistant Staphylococcus aureus [MRSA]) and gram-negative organisms. Chemically distinct from other quinolones, delafloxacin exhibits enhanced potency, particularly against gram-positive pathogens. The integration of efficacy data across the Phase III ABSSSI studies is presented here and allows for additional examination of results across subgroups.

METHODS

Results of 2 multicenter, randomized, double-blind trials of 1510 adults with ABSSSI were pooled for this analysis. Subjects in the vancomycin arm received 15 mg/kg, plus 1-2 g of aztreonam every 12 hours. Delafloxacin was dosed at 300 mg IV every 12 hours in Study 302; dosing in Study 303 was 300 mg IV every 12 hours for 3 days, with a mandatory, blinded switch to delafloxacin at 450 mg orally every 12 hours. The primary endpoint was objective response (OR), defined as a ≥20% reduction of lesion spread of erythema area at the primary infection site at 48 to 72 hours (±2 hours), in the absence of clinical failure. Investigator-assessed response, based on the resolution of signs and symptoms at follow-up (FU; Day 14 ± 1) and late follow-up (LFU; Day 21- 28), were secondary endpoints.

RESULTS

In the intent-to-treat analysis set, the OR was 81.3% in the delafloxacin arm and 80.7% in the comparator arm (mean treatment difference 0.8%, 95% confidence interval -3.2% to 4.7). Results for OR in the defined subgroups showed delafloxacin to be comparable to vancomycin/aztreonam. Investigator-assessed success was similar at FU (84.7% versus 84.1%) and LFU (82.0% versus 81.7%). Delafloxacin was comparable to vancomycin/aztreonam in the eradication of MRSA, at 98.1% versus 98.0%, respectively, at FU. The frequencies of treatment-emergent adverse events between the groups were similar.

CONCLUSIONS

Overall, IV/oral delafloxacin fixed-dose monotherapy was non-inferior to IV vancomycin/aztreonam combination therapy and was well tolerated in each Phase III study, as well as in the pooled analysis, regardless of endpoint or analysis population.

Therapeutic Drug Monitoring of Beta-Lactams and Other Antibiotics in the Intensive Care Unit: Which Agents, Which Patients and Which Infections?

Antibiotics are among the medications most frequently administered to the critically ill, a population with high levels of intra- and inter-individual pharmacokinetic variability. Our knowledge of the relationships among antibiotic dosing, exposure and clinical effect in this population has increased in recent decades. Therapeutic drug monitoring (TDM) of serum antibiotic concentrations is the most practical means of assessing adequate antibiotic exposure, though until recently, it has been underutilised for this end. Now TDM is becoming more widespread, particularly for the beta-lactam antibiotics, a class historically thought to have a wide therapeutic range. We review the basic requirements, indications, and targets for effective TDM of the glycopeptides, aminoglycosides, quinolones and beta-lactam antibiotics in the adult intensive-care setting, with a special focus on TDM of the beta-lactam antibiotics, the most widely used antibiotic class.

Glucocorticoids dosing in obese subjects: A systematic review

Glucocorticoids (GCs) are amongst the most widely used and effective treatments to control inflammatory and autoimmune diseases. In obese subjects, drug dosing adjusted by body weight is problematic, all the more so as patients are at higher risk of GC metabolic side effects. We propose here to describe the determinants of drug pharmacokinetics (PK) in obese subjects and GC pharmacology, and to identify the existing PK studies that may help discussing the best size descriptor for GC dosing in obese subjects. A clinician and a pharmacist screened PubMed using the MeSH Terms: "glucocorticoids" OR "steroidal agents" AND "pharmacokinetics" AND "obesity" OR "overweight". The search was limited to the publications written in English language and to those performed in humans. A systematic search using the MeSH terms was performed until August 31st, 2017. Only three such PK studies have been published so far that compare dexamethasone, prednisolone and methylprednisolone in obese and normal weight subjects. The studies concur that GC partially distribute in the excess of body weight and that adjustment by total body weight (TBW) or by body weight (BW) excess would increase the initial plasma GC concentration after a loading dose and would thus be inappropriate. Contradictory results are observed regarding GC exposure or clearance according to the GC studied. Behind this overwhelming lack of conclusive evidence for adjusting GC by body weight, further PK studies are clearly needed for guiding their dosing. Furthermore, studies demonstrated an increased sensibility to GC, even when GC exposure was reduced, suggesting that adjustment by body weight may not only be unnecessary but also dangerous.

Daptomycin dosing in obese patients: analysis of the use of adjusted body weight versus actual body weight

Background

Food and Drug Administration-approved daptomycin dosing uses actual body weight, despite limited dosing information for obese patients. Studies report alterations in daptomycin pharmacokinetics and creatine phosphokinase elevations associated with higher weight-based doses required for obese patients. Limited information regarding clinical outcomes with alternative daptomycin dosing strategies in obesity exists.

Objective

This study evaluates equivalency of clinical and safety outcomes in obese patients with daptomycin dosed on adjusted body weight versus a historical cohort using actual body weight.

Methods

This retrospective, single center study compared equivalency of outcomes with two one-sided tests in patients with body mass index ⩾30 kg/m² who received daptomycin dosed on actual body weight versus adjusted body weight. The primary outcome was clinical failure. Secondary outcomes included 90-day readmission and 90-day mortality. A combined safety endpoint included creatine phosphokinase elevation, patient-reported myopathy, and rhabdomyolysis.

Results

A total of 667 patients were screened for inclusion; 101 patients were analyzed with 50 in the actual body weight cohort and 51 in the adjusted body weight cohort. The two regimens were statistically equivalent for clinical failure (2% actual body weight versus 4% adjusted body weight; p < 0.001 for equivalency). The two regimens were also statistically equivalent for 90-day mortality (6% actual body weight versus 4% adjusted body weight; p = 0.0014 for equivalency). Limitations include single center, retrospective design, and sample size. Daptomycin dosing intensified throughout the study period.

Conclusion

The two daptomycin dosing cohorts were statistically equivalent for both clinical failure and 90-day mortality. More data are needed to assess outcomes with higher (⩾8 mg/kg/day) daptomycin doses in this patient population.

Cefazolin Prophylaxis for Total Joint Arthroplasty: Obese Patients Are Frequently Underdosed and at Increased Risk of Periprosthetic Joint Infection

BACKGROUND

One of the most effective prophylactic strategies against periprosthetic joint infection (PJI) is administration of perioperative antibiotics. Many orthopedic surgeons are unaware of the weight-based dosing protocol for cefazolin. This study aimed at elucidating what proportion of patients receiving cefazolin prophylaxis are underdosed and whether this increases the risk of PJI.

METHODS

A retrospective study of 17,393 primary total joint arthroplasties receiving cefazolin as perioperative prophylaxis from 2005 to 2017 was performed. Patients were stratified into 2 groups (underdosed and adequately dosed) based on patient weight and antibiotic dosage. Patients who developed PJI within 1 year following index procedure were identified. A bivariate and multiple logistic regression analyses were performed to control for potential confounders and identify risk factors for PJI.

RESULTS

The majority of patients weighing greater than 120 kg (95.9%, 944/984) were underdosed. Underdosed patients had a higher rate of PJI at 1 year compared with adequately dosed patients (1.51% vs 0.86%, P = .002). Patients weighing greater than 120 kg had higher 1-year PJI rate than patients weighing less than 120 kg (3.25% vs 0.83%, P < .001). Patients who were underdosed (odds ratio, 1.665; P = .006) with greater comorbidities (odds ratio, 1.259; P < .001) were more likely to develop PJI at 1 year.

CONCLUSION

Cefazolin underdosing is common, especially for patients weighing more than 120 kg. Our study reports that underdosed patients were more likely to develop PJI. Orthopedic surgeons should pay attention to the weight-based dosing of antibiotics in the perioperative period to avoid increasing risk of PJI.

Predictors of insufficient peak amikacin concentration in critically ill patients on extracorporeal membrane oxygenation

Background

Amikacin infusion requires targeting a peak serum concentration (C_max) 8–10 times the minimal inhibitory concentration, corresponding to a C_max of 60–80 mg/L for the least susceptible bacteria to theoretically prevent therapeutic failure. Because drug pharmacokinetics on extracorporeal membrane oxygenation (ECMO) are challenging, we undertook this study to assess the frequency of insufficient amikacin C_max in critically ill patients on ECMO and to identify relative risk factors.

Methods

This was a prospective, observational, monocentric study in a university hospital. Patients on ECMO who received an amikacin loading dose for suspected Gram-negative infections were included. The amikacin loading dose of 25 mg/kg total body weight was administered intravenously and C_max was measured 30 min after the end of the infusion. Independent predicators of C_max < 60 mg/L after the first amikacin infusion were identified with mixed-model multivariable analyses. Various dosing simulations were performed to assess the probability of reaching 60 mg/L < C_max < 80 mg/L.

Results

A total of 106 patients on venoarterial ECMO (VA-ECMO) (68%) or venovenous-ECMO (32%) were included. At inclusion, their median (1st; 3rd quartile) Sequential Organ-Failure Assessment score was 15 (12; 18) and 54 patients (51%) were on renal replacement therapy. Overall ICU mortality was 54%. C_max was < 60 mg/L in 41 patients (39%). Independent risk factors for amikacin under-dosing were body mass index (BMI) < 22 kg/m² and a positive 24-h fluid balance. Using dosing simulation, increasing the amikacin dosing regimen to 30 mg/kg and 35 mg/kg of body weight when the 24-h fluid balance is positive and the BMI is ≥ 22 kg/m² or < 22 kg/m² (Table 3), respectively, would have potentially led to the therapeutic target being reached in 42% of patients while reducing under-dosing to 23% of patients.

Conclusions

ECMO-treated patients were under-dosed for amikacin in one third of cases. Increasing the dose to 35 mg/kg of body weight in low-BMI patients and those with positive 24-h fluid balance on ECMO to reach adequate targeted concentrations should be investigated.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2122-x) contains supplementary material, which is available to authorized users.