Impact of hypoalbuminemia on clinical outcomes among patients with obesity treated with ceftriaxone

The use of ceftriaxone, a highly protein-bound drug, in the setting of hypoalbuminemia may result in suboptimal drug exposure. Patients with obesity also exhibit higher absolute drug clearance. We aimed to evaluate the impact of hypoalbuminemia on clinical success among hospitalized adults with obesity who were treated with ceftriaxone. This retrospective review included adult inpatients with weight >100 kg or body mass index >40 kg/m2 who received ceftriaxone 2 g intravenously every 12 hours for at least 72 hours. The primary outcome was clinical success, a composite of clinical cure and microbiologic cure. Secondary outcomes included clinical cure, microbiologic cure, length of stay, ICU length of stay, mortality, 30-day readmission, and adverse events. In all, 137 patients were included, 34 of whom had a serum albumin of ≤2.5 g/dL. In a propensity-score-weighted analysis, clinical success was significantly more common among those without hypoalbuminemia (91.2%) as compared to those with hypoalbuminemia (77.8%) (P = 0.038). Death within 30 days (13.7% vs 0%, P < 0.001) and 30-day readmission (31.6% vs 12.0%, P = 0.008) were more common in the hypoalbuminemia group. In a univariate analysis, serum albumin and indication for ceftriaxone use were found to be predictors of clinical success. Hypoalbuminemia was associated with a lower rate of clinical success among patients with obesity who were treated with ceftriaxone 2 g every 12 hours.

Pharmacotherapeutic Considerations in the Treatment of Nontuberculous Mycobacterial Infections: A Primer for Clinicians

Nontuberculous mycobacteria (NTM) can cause a variety of infections, including serious pulmonary disease. Treatment encompasses polypharmacy, with a targeted regimen of 2-5 active medications, depending on site of infection, species, and clinical characteristics. Medications may include oral, intravenous, and inhalational routes. Medication acquisition can be challenging for numerous reasons, including investigational status, limited distribution models, and insurance prior authorization. Additionally, monitoring and managing adverse reactions and drug interactions is a unique skill set. While NTM is primarily medically managed, clinicians may not be familiar with the intricacies of medication selection, procurement, and monitoring. This review offers insights into the pharmacotherapeutic considerations of this highly complex disease state, including regimen design, medication acquisition, safety monitoring, relevant drug-drug interactions, and adverse drug reactions.

Comparable outcomes of outpatient remdesivir and sotrovimab among high-risk patients with mild to moderate COVID-19 during the omicron BA.1 surge

Studies conducted prior to SARS-CoV-2 Omicron demonstrated that sotrovimab and remdesivir reduced hospitalization among high-risk outpatients with mild to moderate COVID-19. However, their effectiveness has not been directly compared. This study examined all high-risk outpatients with mild to moderate COVID-19 who received either remdesivir or sotrovimab at Mayo Clinic during the Omicron BA.1 surge from January to March 2022. COVID-19-related hospitalization or death within 28 days were compared between the two treatment groups. Among 3257 patients, 2158 received sotrovimab and 1099 received remdesivir. Patients treated with sotrovimab were younger and had lower comorbidity but were more likely to be immunocompromised than remdesivir-treated patients. The majority (89%) had received at least one dose of COVID-19 vaccine. COVID-19-related hospitalization (1.5% and 1.0% in remdesivir and sotrovimab, respectively, p = .15) and mortality within 28 days (0.4% in both groups, p = .82) were similarly low. A propensity score weighted analysis demonstrated no significant difference in the outcomes between the two groups. We demonstrated favorable outcomes that were not significantly different between patients treated with remdesivir or sotrovimab.

We Shape Our Tools and Then Our Tools Shape Us: OPAT and the EHR

A commentary on Canterino et al. (2024) and Munsiff et al. (2024), articles where clinicians from two large OPAT programs.

HIV Pre-Exposure Prophylaxis: New and Upcoming Drugs to Address the HIV Epidemic

Human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) provides a critical intervention toward ending the HIV epidemic and protecting people with reasons to utilize PrEP. PrEP options continue to expand as new administration modalities offer the potential to tailor PrEP use for individual success. We have provided the evidence for new and emerging antiretroviral agents for PrEP (cabotegravir, lenacapavir, dapivirine, and broadly neutralizing antibodies), divided into pharmacology, animal model, and human data, accompanied by a summary and suggested place in therapy. Cabotegravir is a US Food and Drug Administration (FDA)-approved intramuscular injection given every 2 months with a strong body of evidence demonstrating efficacy for HIV PrEP, lenacapavir administered subcutaneously every 6 months is currently under investigation for HIV PrEP, dapivirine vaginal ring is an available PrEP option for women in certain areas of Africa, and broadly neutralizing monoclonal antibodies have been challenged in demonstrating efficacy in phase 1-2 study for HIV PrEP to date. Clinical literature for individual agents is discussed with data from major studies summarized in tables. This review provides a detailed overview of recently available and premier candidate PrEP drugs.

CLinician and patient characteristics effect on Antimicrobial Stewardship Interventions (CLASI) study

OBJECTIVE

To determine whether the gender of clinicians making antimicrobial stewardship recommendations has an impact on intervention acceptance rate.

DESIGN

A retrospective, multivariable analysis of antimicrobial stewardship prospective audit and feedback outcomes.

SETTING

A multisite healthcare system including Mayo Clinic Rochester (MN), Mayo Clinic Arizona, Mayo Clinic Florida and 17 health-system hospital sites, where prospective audit and feedback is performed and documented within an electronic tool embedded in the medical record.

PARTICIPANTS

The study included 143 Mayo Clinic clinicians (84 cisfemales and 59 cismales).

METHODS

Outcomes were analyzed from July 1, 2017, to June 30, 2022, for intervention rates, communication methods, and intervention acceptance by clinician gender, profession, patient age, and intensive care unit (ICU) status of patient.

RESULTS

Of 81,927 rules, 71,729 rules met study inclusion. There were 18,175 (25%) rules associated with an intervention. Most of the rules were reviewed by pharmacists (86.2%) and stewardship staff (85.5%). Of 10,363 interventions with an outcome documented, 8,829 (85.2%) were accepted and 1,534 (14.8%) were rejected. Female clinicians had 6,782 (86.5%) of 7,843 interventions accepted, and male clinicians had 2,047 (81.2%) of 2,520 interventions accepted (P = .19). Female patients had more interventions than male patients (female vs male: 25.9% vs 24.9%; OR, 1.04; 95% CI, 1.02-1.08; P = .001). Patients in the ICU had a significantly lower intervention acceptance rate (ICU vs non-ICU: 78.2% vs 86.7%; OR, 0.56; 95% CI, 0.45-0.7; P < .001).

CONCLUSIONS

Female and male clinicians were equally effective at prospective audit and feedback in a multisite antimicrobial stewardship program. Patients in the ICU were less likely to have stewardship interventions accepted.

Evaluating antimicrobial duration for Gram-negative bacteremia in patients with neutropenia due to hematologic malignancy or hematopoietic stem cell transplantation

BACKGROUND

In the management of Gram-negative bloodstream infection (GN-BSI), short antimicrobial courses have been increasingly demonstrated to be non-inferior to prolonged therapy, with lower risk of Clostridioides difficile infection (CDI) and emergence of multi-drug resistant (MDR) organisms. However, immunocompromised hosts were excluded from these studies. We investigated outcomes of short (≤10 days), intermediate (11-14 days), and prolonged (≥15 days) antimicrobial durations for GN-BSI in neutropenic patients.

METHODS

A retrospective cohort study was conducted on neutropenic patients with monomicrobial GN-BSI between 2018 and 2022. The primary outcome was a composite of all-cause mortality and microbiologic relapse within 90 days after therapy completion. The secondary outcome was a composite of 90-day CDI and development of MDR-GN bacteria. Cox regression analysis with propensity score (PS) adjustment was used to compare outcomes between the three groups.

RESULTS

A total of 206 patients were classified into short (n = 67), intermediate (n = 81), or prolonged (n = 58) duration. Neutropenia was predominantly secondary to hematopoietic stem cell transplantation (48%) or hematologic malignancy (35%). The primary sources of infection included intra-abdominal (51%), vascular catheter (27%), and urinary (8%). Most patients received definitive therapy with cefepime or carbapenem. No significant difference in the primary composite endpoint was observed for intermediate versus short (PS-adjusted hazard ratio [aHR] 0.89; 95% confidence interval [95% CI] 0.39-2.03) or prolonged versus short therapy (PS-aHR 1.20; 95% CI 0.52-2.74). There was no significant difference in the secondary composite endpoint of CDI or MDR-GN emergence.

CONCLUSION

Our data suggest that short antimicrobial courses had comparable 90-day outcomes as intermediate and prolonged regimens for GN-BSI among immunocompromised patients with neutropenia.

A Pharmacovigilance Analysis of Daptomycin Use Based on CLSI Susceptible Dose-Dependent Category

INTRODUCTION

Daptomycin doses 8-12 mg/kg are recommended for susceptible dose-dependent Enterococcus species. However, data remain limited on safety outcomes of such dosing, compared to standard 4-6 mg/kg dosing.

METHODS

In this retrospective cohort study, patients were stratified into daptomycin standard-dose (≤ 6.5 mg/kg) versus high-dose (≥ 7.5 mg/kg) groups. The primary outcome was daptomycin safety based on a composite of creatine kinase elevation, daptomycin-related peripheral blood eosinophilia, eosinophilic pneumonitis, alanine aminotransferase elevation, and alkaline phosphatase elevation. A secondary aim was to identify risk factors for daptomycin adverse effects. Inclusion criteria were age ≥ 18 years old, daptomycin receipt for ≥ 48 h, and Enterococcus cultures with a daptomycin minimal inhibitory concentration 2-4 mg/L.

RESULTS

A total of 119 patients were included for analysis. Median daptomycin doses were 6.0 mg/kg (IQR 5.4, 6.1) and 8.1 mg/kg (IQR 7.9, 9.6) in the standard- and high-dose cohorts, respectively. Median durations were 13.5 days (standard-dose) and 16 days (high-dose) (p = 0.02). The composite safety endpoint occurred in 32.0% of the standard-dose group and 32.5% of the high-dose group (p = 0.96). Daptomycin was dose-reduced or held in 8.1% of patients experiencing an adverse effect. Concurrent antihistamine usage was associated with the composite outcome; however, there was no association with daptomycin dose or concurrent statin use.

CONCLUSION

High-dose daptomycin was not associated with increased laboratory abnormalities or adverse drug reactions compared to standard-dose daptomycin.

Association of adverse effects with high serum posaconazole concentrations

Posaconazole therapeutic drug monitoring (TDM) is widely utilized to assess therapeutic efficacy and safety; however, clinical effects of very high serum concentrations are unknown. A retrospective review of 90 patients receiving posaconazole for treatment or prophylaxis of invasive fungal infections with serum concentrations ≥3000 ng/mL from 1/1/2019 to 4/30/2021 evaluated the incidence and type of adverse drug reactions (ADRs). Symptomatic ADRs were very common in patients with posaconazole concentrations of ≥5000 ng/mL and 3000-4999 ng/mL (80% vs. 58.8%; P = 0.31). Posaconazole TDM should be performed for both treatment and prophylaxis indications and dose decrease for serum concentrations >3000 ng/mL should be considered.

Pharmacogenomic panel testing provides insight and enhances medication management in people with HIV

OBJECTIVE

Our study aimed to assess the impact of pharmacogenomic panel testing in people with HIV (PWH).

DESIGN

Prospective, observational intervention assessment.

METHODS

One hundred PWH were provided a comprehensive pharmacogenomic panel during routine care visits within the HIV specialty clinic of a large academic medical center. The panel determined the presence of specific genetic variants that could predict response or toxicity to commonly prescribed antiretroviral therapy (ART) and non-ART medications. An HIV specialty pharmacist reviewed the results with participants and the care team. The pharmacist (1) recommended clinically actionable interventions based on the participants' current drug therapy, (2) assessed for genetic explanations for prior medication failures, adverse effects, or intolerances, and (3) advised on potential future clinically actionable care interventions based on individual genetic phenotypes.

RESULTS

Ninety-six participants (median age 53 years, 74% white, 84% men, 89% viral load <50 copies/ml) completed panel testing, yielding 682 clinically relevant pharmacogenomic results (133 major, 549 mild-moderate). Ninety participants (89 on ART) completed follow-up visits with 65 (72%) receiving clinical recommendations based on current medication profiles. Of the 105 clinical recommendations, 70% advised additional monitoring for efficacy or toxicity, and 10% advised alteration of drug therapy. Panel results offered explanation for prior ART inefficacy in one participant and ART intolerance in 29%. Genetic explanation for non-ART toxicity was seen in 21% of participants, with genetic contributors to inefficacy of non-ART therapy identified in 39% of participants.

CONCLUSION

Preliminary data in a small cohort of PWH demonstrates benefit of routine pharmacogenomic panel testing.

'How to' Guide for Pharmacist-led Implementation of Beta-Lactam Therapeutic Drug Monitoring in the Critically Ill

Beta-lactam therapeutic drug monitoring (TDM) can improve precision dosing and clinical outcomes in critically ill patients, but has not been implemented widely in the United States. Mayo Clinic recently implemented a beta-lactam TDM program. This single-center experience forms the basis of the manuscript which outlines practical considerations involved with implementation, including the pharmacist's role as a leader. Our implementation effort focused on three primary domains. First, we aimed to ensure a supportive organizational infrastructure. Early leadership engagement by the pharmacist-led core team facilitated advocacy for the clinical need, allocation of resources, and assay development. Second, core clinical workflows were developed that addressed the preferred patient population for use, desirable pharmacokinetic and pharmacodynamic targets, and the preferred sampling strategy. Clinical tools to guide pharmacists in interpreting the results (e.g., pharmacokinetics calculator) and documenting decisions were developed. Third, stakeholders were offered repeated exposure to evidence and expertise to facilitate understanding and application of the new practice. This act of 'individual internalization' seems to be uniquely important to beta-lactam TDM implementation compared with implementation of other antimicrobial TDM programs. Educational strategies and supportive materials that were developed were focused on providing substantive and varied information tailored to the stakeholders' role in the process. For pharmacists, this included both clinical and operational considerations. A continuous improvement plan to support management of the process was instituted to address necessary updates and changes that inevitably emerged. In summary, the described approach to implementation of a pharmacist led beta-lactam TDM program could be used as a roadmap to aid other institutions that aim to develop such a program.

Why is the Implementation of Beta-Lactam Therapeutic Drug Monitoring for the Critically Ill Falling Short? A Multicenter Mixed-Methods Study

BACKGROUND

Beta-lactam therapeutic drug monitoring (BL TDM; drug level testing) can facilitate improved outcomes in critically ill patients. However, only 10%-20% of hospitals have implemented BL TDM. This study aimed to characterize provider perceptions and key considerations for successfully implementing BL TDM.

METHODS

This was a sequential mixed-methods study from 2020 to 2021 of diverse stakeholders at 3 academic medical centers with varying degrees of BL TDM implementation (not implemented, partially implemented, and fully implemented). Stakeholders were surveyed, and a proportion of participants completed semistructured interviews. Themes were identified, and findings were contextualized with implementation science frameworks.

RESULTS

Most of the 138 survey respondents perceived that BL TDM was relevant to their practice and improved medication effectiveness and safety. Integrated with interview data from 30 individuals, 2 implementation themes were identified: individual internalization and organizational features. Individuals needed to internalize, make sense of, and agree to BL TDM implementation, which was positively influenced by repeated exposure to evidence and expertise. The process of internalization appeared more complex with BL TDM than with other antibiotics (ie, vancomycin). Organizational considerations relevant to BL TDM implementation (eg, infrastructure, personnel) were similar to those identified in other TDM settings.

CONCLUSIONS

Broad enthusiasm for BL TDM among participants was found. Prior literature suggested that assay availability was the primary barrier to implementation; however, the data revealed many more individual and organizational attributes, which impacted the BL TDM implementation. Internalization should particularly be focused on to improve the adoption of this evidence-based practice.

A Bundle of the Top 10 OPAT Publications in 2022

Outpatient parenteral antimicrobial therapy (OPAT) has become more common in clinical settings. Correspondingly, OPAT-related publications have also increased; the objective of this article was to summarize clinically meaningful OPAT-related publications in 2022. Seventy-five articles were initially identified, with 54 being scored. The top 20 OPAT articles published in 2022 were reviewed by a group of multidisciplinary OPAT clinicians. This article provides a summary of the "top 10" OPAT publications of 2022.

Heartbreaking Decisions: The Dogma and Uncertainties of Antimicrobial Therapy in Infective Endocarditis

Infective endocarditis (IE) is a rare but increasingly prevalent disease with high morbidity and mortality, requiring antimicrobials and at times surgical intervention. Through the decades of healthcare professionals' experience with managing IE, certain dogmas and uncertainties have arisen around its pharmacotherapy. The introduction of new antimicrobials and novel combinations are exciting developments but also further complicate IE treatment choices. In this review, we provide and evaluate the relevant evidence focused around contemporary debates in IE treatment pharmacotherapy, including beta-lactam choice in MSSA IE, combination therapies (aminoglycosides, ceftaroline), the use of oral antimicrobials, the role of rifamycins, and long-acting lipoglycopeptides.

Clinical outcomes of COVID-19 treated with remdesivir across the continuum of care

Introduction

During the early phase of the coronavirus disease 2019 (COVID-19), remdesivir was only approved for hospitalized patients. Our institution developed hospital-based, outpatient infusion centers for selected hospitalized patients with COVID-19 who had clinical improvement to allow for early dismissal. The outcomes of patients who transitioned to complete remdesivir in the outpatient setting were examined.

Methods

Retrospective study of all hospitalized adult patients with COVID-19 who received at least one dose of remdesivir from November 6, 2020, to November 5, 2021, at one of the Mayo Clinic hospitals.

Results

Among 3029 hospitalized patients who received treatment with remdesivir for COVID-19, the majority (89.5%) completed the recommended 5-day course. Among them, 2169 (80%) patients completed treatment during hospitalization, whereas 542 (20.0%) patients were dismissed to complete remdesivir in outpatient infusion centers. Patients who completed the treatment in the outpatient setting had lower odds of death within 28 days (aOR 0.14, 95% CI 0.06-0.32, p < 0.001). However, their rate of subsequent hospital encounters within 30 days was higher (aHR 1.88, 95% CI 1.27-2.79, p = 0.002). Among patients treated with remdesivir only in the inpatient setting, the adjusted odds of death within 28 days were significantly higher among those who did not complete the 5-day course of remdesivir (aOR 2.07, 95% CI 1.45-2.95, p < 0.001).

Conclusions

This study describes the clinical outcomes of a strategy of transitioning remdesivir therapy from inpatient to outpatient among selected patients. Mortality was lower among patients who completed the 5-day course of remdesivir.

Vancomycin AUC values estimated with trough-only data: Accuracy in an adult academic medical center population

PURPOSE

Vancomycin area under the concentration-time curve (AUC) can be calculated using steady-state serum peak and trough concentrations; however, compared to traditional trough-only monitoring, this approach requires an additional blood sample. Recently published data demonstrated vancomycin AUC estimations using trough-only data with a volume of distribution (Vd) model incorporating age and actual body weight were reasonably accurate and precise in a veteran population. This study sought to extend these methods to a Mayo Clinic adult population.

METHODS

A retrospective, observational cohort of adult patients with documented steady-state vancomycin peak and trough concentrations was evaluated. Vancomycin AUCs were estimated using trough-only data, and 4 Vd models were assessed for accuracy and precision. Estimated AUCs were compared to AUCs calculated using 1-compartment intermittent infusion equations and steady-state peak and trough ("peak-trough") data.

RESULTS

The study population (N = 95) was 46% female, with a median age of 59 years and a median weight of 97 kg. Using the VancoPK equation Vd = 0.29 (age in y) + 0.33 (actual weight in kg) + 11, the mean peak-trough and estimated trough-only AUC were 533 and 534, respectively, with a correlation of 0.936. The root mean square error was 47.7, meaning about 95% of AUCs were within 95 mg · h/L of peak-trough AUCs.

CONCLUSIONS

Accuracy and precision of Vancomycin AUC estimations using trough-only data and the described Vd model were demonstrated in a Mayo Clinic cohort. Targeting an estimated AUC of 500 mg · h/L using the VancoPK model would likely result in an actual AUC within 400 to 600 mg · h/L.

Contemporary Pharmacotherapies for Nontuberculosis Mycobacterial Infections: A Narrative Review

Nontuberculous mycobacteria (NTM) are a group of atypical bacteria that may cause a spectrum of clinical manifestations, including pulmonary, musculoskeletal, skin and soft tissue, and cardiac infections. Antimycobacterial medication regimens for NTM infections require multiple agents with prolonged treatment courses and are often associated with poor tolerance in patients and suboptimal clinical outcomes. This review summarizes NTM pharmacotherapy, including treatment concepts, preferred medication regimens according to NTM species and site of infection, and emerging treatment methods for difficult-to-treat species.

Does metabolite matter? Defining target itraconazole and hydroxy-itraconazole serum concentrations for blastomycosis

BACKGROUND

Itraconazole is the recommended first-line treatment for mild-to-moderate blastomycosis and consolidation treatment of moderate-to-severe disease. Itraconazole is metabolised into three metabolites, including an active metabolite hydroxy-itraconazole. Literature provides little evidence indicating whether therapeutic drug monitoring targets should be based on itraconazole parent compound alone or a sum of itraconazole and hydroxy-itraconazole serum concentrations.

OBJECTIVES

This study aims to compare clinical outcomes and adverse drug events (ADEs) of combined itraconazole and hydroxy-itraconazole concentrations versus itraconazole parent compound alone in patients with blastomycosis.

PATIENTS/METHODS

This study was a retrospective cohort review of patients ≥18 years with probable or proven Blastomyces infection who received itraconazole with at least one documented serum itraconazole concentration. The primary outcome was rate of partial or complete treatment response across three patient groups: (1) Itraconazole parent compound >1.0 mcg/ml (parent), (2) parent compound <1.0 mcg/ml, but a combined itraconazole and hydroxy-itraconazole >1.0 mcg/ml (combined) and (3) failure to achieve a combined or parent concentration >1.0 mcg/ml (subtherapeutic) for >75% of the duration of itraconazole therapy.

RESULTS

A total of 80 patients were included (parent = 32, combined = 36, subtherapeutic = 12). No statistically significant difference was observed for rate of partial or complete treatment response (97% parent vs 94% combined, p = .99). Significantly higher mortality due to blastomycosis was observed in patients in the subtherapeutic group (0% parent vs 3% combined vs 25% subtherapeutic, p = .01).

CONCLUSIONS

This study supports an itraconazole therapeutic target combining itraconazole and hydroxy-itraconazole >1.0 mcg/ml for blastomycosis treatment.

Taking the route less traveled: on the way to COpAT

Antimicrobial therapy is an essential practice within medicine. Over the last 4 years, complex outpatient antimicrobial therapy (COpAT) with oral antimicrobials has become a rapidly developing area of practice and is non-inferior to outpatient parenteral antimicrobial therapy (OPAT) in certain infectious syndromes. Currently, the available literature does not describe the implementation of oral antimicrobials within the current outpatient antimicrobial therapy process. Throughout this article, the authors present a review of current literature, a proposed definition of COpAT and offer methods readers can utilize to implement an integrated COpAT/OPAT program with oral antimicrobial-specific monitoring within their current practice.

A review of evidence, antimicrobial stability, and feasibility considerations for OPAT continuous infusion

Outpatient parenteral antimicrobial therapy (OPAT) has been widely used in clinical practice for many decades because of its associated cost savings, reductions in inpatient hospital days, and decreases in hospital-associated infections. Despite this long history, evolving practice patterns and new drug delivery devices continue to present challenges as well as opportunities for clinicians when designing appropriate outpatient antimicrobial regimens. One such change is the increasing use of extended and continuous infusion (CI) of antimicrobials to optimize the achievement of pharmacokinetic and pharmacodynamic targets. Elastomeric devices are also becoming increasingly popular in OPAT, including for the delivery of CI. In this article, we review the clinical evidence for CI in OPAT, as well as practical considerations of patient preferences, cost, and antimicrobial stability.

Pushing the agenda for intravenous push administration in outpatient parenteral antimicrobial therapy

Intravenous push (IVP) antimicrobial administration refers to rapid bolus infusion of medication. This drug delivery method offers improved patient convenience, superior patient and nursing satisfaction, and cost savings when used in outpatient parenteral antimicrobial therapy (OPAT). Antimicrobial agents must demonstrate optimal physiochemical and pharmacologic characteristics, as well as sufficient syringe stability, to be administered in this manner. Additionally, impacts on medication tolerability, patient safety, and effectiveness must be considered. This narrative review summarizes the available data and practical implications of IVP administration of antimicrobials in the OPAT setting.

Comparative renal risk of long-term use of beta-lactams in combination with vancomycin across the continuum of care

Background

Data are controversial regarding nephrotoxicity risk with vancomycin plus piperacillin-tazobactam (VPT) compared to vancomycin alone or in combination with other beta-lactams (BLs) in acute care use. Furthermore, data are lacking on the incidence of acute kidney injury (AKI) with long-term use of VPT including outpatient parenteral antimicrobial therapy (OPAT).

Methods

This retrospective study included 826 adult patients on an intravenous vancomycin plus BL for ⩾2 weeks, including cefepime, piperacillin/tazobactam, ertapenem, or meropenem, from August 2017 to January 2022. The primary outcome was incidence of AKI. Univariate and multivariable Cox proportional hazard regression analyses were conducted to adjust for confounding variables. A secondary analysis based on the propensity score (PS)-matched cohort was performed.

Results

AKI occurred in 14.4% of patients in the VPT group (n = 15/104) compared to 5.5% in the other BL group (n = 40/722) (p < 0.001). Average time to AKI from start of combination therapy was 9.4 (1.7-12.0) days in the VPT group and 10.9 (5-22.7) days in the other BL group (p = 0.20). The median duration of vancomycin and BL in the overall cohort was approximately 1 month. Beyond BL selection, patient characteristics were not associated with AKI other than the receipt of concomitant acyclovir [hazard ratio (HR) 2.48 (95% confidence interval (CI): 1.33-4.65), p = 0.004]. In the PS-matched cohort, AKI occurred in 14.4% of patients in the VPT group (n = 15/104) and 5.3% in the other BL group (n = 11/208) (p = 0.006). Receipt of VPT [HR: 2.55 (1.36-4.78), p = 0.004] and acyclovir [HR: 2.38 (1.19-4.74), p = 0.014) remained significantly associated with AKI in the multivariable model.

Conclusion

Clinicians should exercise caution when using VPT for >2 weeks, including in the OPAT setting, even when no renal dysfunction is observed during the initial week of combination therapy.

743. Implementation of Beta-Lactam Therapeutic Drug Monitoring Programs in the Critically Ill: A Multicenter Mixed-Methods Study

Background

Beta-lactam therapeutic drug monitoring (BL TDM; drug level testing) can facilitate improved outcomes in critically ill patients. Yet less than 20% of hospitals have implemented BL TDM. The purpose of this study was to characterize provider perceptions and key considerations for successful implementation of BL TDM.

Methods

This was a sequential mixed methods study from 2020 to 2021 of stakeholders at three academic medical centers with varying degrees of BL TDM implementation - Mayo Clinic (BL TDM not implemented), University of Florida Health Shands (partially implemented), and Royal Brisbane and Women’s Hospital (fully implemented). Stakeholders completed a survey to characterize their knowledge, perceptions, and experience with BL TDM. A diverse group of 30 respondents were then purposively sampled for semi-structured interviews. Results from the two strands were integrated, themes were identified, and findings were situated within implementation science frameworks.

Results

Among the 138 survey respondents (22% response rate), the majority were physicians (38%) and pharmacists (33%). 71% practiced in critical care and 21% in infectious diseases. The majority of respondents felt BL TDM was relevant to their practice and improved medication effectiveness and safety (Figure 1). Two implementation themes were identified: individual internalization and organizational features. Individuals needed to internalize, make sense of, and agree to BL TDM implementation which was positively influenced by repeated exposure to evidence and expertise. The process of internalization seemed more complex with BL TDM than with other antibiotics (i.e., vancomycin). Organizational considerations relevant to BL TDM implementation included adequate physical and informational infrastructure, access to trained personnel, supportive governance/leadership, and robust process and workflow development.

Conclusion

We found broad enthusiasm about the relevance and potential benefits of BL TDM among stakeholders. Prior literature suggested the primary barrier to implementation was assay availability, but we identified many more individual and organizational attributes which impacted the scale and spread of BL TDM.

Disclosures

Sara Ausman, PharmD, Gilead: Honoraria Christina G. Rivera, PharmD, Gilead: Grant/Research Support|Gilead: Honoraria|Insmed: Honoraria Jason Roberts, BPharm(Hons), PhD, FSHP, FISAC, British Society of Chemotherapy: Grant/Research Support|Cipla: Honoraria|Gilead: Advisor/Consultant|MSD: Advisor/Consultant|MSD: Honoraria|Pfizer: Board Member|Pfizer: Honoraria|Qpex: Grant/Research Support|Sandoz: Board Member|Summit: Advisor/Consultant|Wolters Kluwer: Advisor/Consultant Marc H. Scheetz, PharmD, MSc, Abbvie: Advisor/Consultant|Allecra: Grant/Research Support|Merck: Advisor/Consultant|Nevakar: Advisor/Consultant|Nevakar: Grant/Research Support|Premier Healthcare Solutions: Honoraria|Spero: Advisor/Consultant|SuperTrans Medical: Advisor/Consultant|SuperTrans Medical: Grant/Research Support|Takeda: Advisor/Consultant|Third Pole Therapeutics: Advisor/Consultant.

1752. Impact of a multifaceted, outpatient antimicrobial stewardship intervention bundle on unnecessary antimicrobial prescribing in upper respiratory tract infections (URI)

Background

URIs are the most common indication for outpatient antibiotic prescribing. Given high rates of unnecessary prescribing, these indications have been identified as a high-priority target for outpatient antimicrobial stewardship programs (ASP). Our primary objective was to evaluate the impact of a system-wide, multifaceted, outpatient ASP intervention bundle on unnecessary antibiotic prescribing for URI.

Methods

This quasi-experimental study was conducted from 2019 to 2021. ICD-10 codes for URIs were grouped into 3 tiers (i.e., tier I = antibiotics always indicated, tier II = sometimes, tier III = never). Encounters from 5 care specialties (i.e., family medicine, community internal medicine, express care, pediatrics, and emergency department) with a tier III URI primary ICD-10 code but without a secondary tier I or tier II code were included. COVID-19 ICD-10 codes were excluded. Interventions included construction of a prescribing data model, dissemination of clinician prescribing data and education, promotion of symptom management strategies, a patient-facing commitment poster, and a pre-populated URI order panel. Tools were designed at a system level and implemented by regional champions beginning in the 3rd quarter of 2020. The primary outcome was the rate of antibiotic prescribing, and the secondary outcome and counterbalance measure was the rate of repeat URI-related healthcare contact within 14 days. Outcomes were analyzed with chi-square with an α level of 0.05.

Results

A total of 147403 encounters were included. The overall antibiotic prescribing rate decreased from 24.1% to 12.3% between 2019 and 2021 (p< 0.01). Significant reductions in tier III antibiotic prescribing were demonstrated for each region, care specialty, and syndrome evaluated (Table 1). A reduction in repeat healthcare contact was seen across the total cohort (9.5% in 2019 vs. 8.3% in 2021, p< 0.01); decreases in repeat contact rates were observed in those not initially receiving an antibiotic (10.3% vs. 8.6%, p< 0.01), but not in those who initially received an antibiotic (6.8% vs. 6.8%, p = 0.94).

Tier III URI encounter level antimicrobial prescribing rates by region, care specialty, and syndrome

Conclusion

A multifaceted, outpatient ASP intervention bundle decreased rates of unnecessary antimicrobial prescribing without increasing rates of 14-day repeat URI-related healthcare contact.

Disclosures

Paschalis Vergidis, MD, AbbVie: DSMB|Cidara: Grant/Research Support|Scynexis: Grant/Research Support Evan Draper, PharmD, Gilead Foundation: Grant/Research Support Sara Ausman, PharmD, Gilead: Honoraria Christina G. Rivera, PharmD, Gilead: Grant/Research Support|Gilead: Honoraria|Insmed: Honoraria.

475. Does Metabolite Matter? Defining Target Itraconazole and Hydroxy-itraconazole Serum Levels for Blastomycosis

Background

Itraconazole is first-line treatment for mild-moderate blastomycosis and consolidation of moderate-severe disease. Itraconazole is metabolized to 3 metabolites, including an active metabolite hydroxy-itraconazole. The sum of itraconazole and hydroxy-itraconazole levels > 1.0 mcg/mL is guideline recommended for treatment of invasive fungal infections; conversely, some experts suggest targeting a parent compound level alone > 1.0 mcg/mL. This study aims to compare clinical outcomes and adverse drug reactions (ADRs) of combined itraconazole and hydroxy-itraconazole levels > 1.0 mcg/mL versus itraconazole parent compound alone > 1.0 mcg/mL in patients with blastomycosis.

Methods

This study is a single-center, retrospective chart review of patients ≥ 18 years with probable or proven Blastomyces infection who received itraconazole with at least one documented serum itraconazole level. The primary outcome was rate of partial or complete treatment response in patients with a combined itraconazole and hydroxy-itraconazole level > 1.0 mcg/mL versus itraconazole parent compound > 1.0 mcg/mL for > 75% of measured levels. ADRs attributable to itraconazole were compared between the groups. Treatment response rates and ADRs were compared between groups using two proportion z-tests.

Results

Total of 80 patients were included: 36 = combined itraconazole and hydroxy-itraconazole > 1.0, 32 = itraconazole parent alone > 1.0, 12 = 75% of all levels < 1.0. No statistically significant difference was observed between groups for blastomycosis rate of partial or complete treatment response (94.3% combined vs 96.6% parent, p=0.99). Significantly higher mortality was observed in patients failing to achieve itraconazole or itraconazole/hydroxy-itraconazole > 1.0 (2.8% combined vs 0% parent vs 25% neither, p=0.01). There was no significant difference in total ADRs between the three groups (p=0.56).

Conclusion

This limited evidence supports an itraconazole therapeutic target combining itraconazole and hydroxy-itraconazole > 1.0 for blastomycosis treatment.

Disclosures

Paschalis Vergidis, MD, AbbVie: DSMB|Cidara: Grant/Research Support|Scynexis: Grant/Research Support Christina G. Rivera, PharmD, Gilead: Grant/Research Support|Gilead: Honoraria|Insmed: Honoraria.

627. Too Much of a Good Thing? The Clinical Effects of Very High Serum Posaconazole Levels

Background

Posaconazole therapeutic drug monitoring (TDM) is widely utilized to assess therapeutic efficacy and safety (i.e., hepatotoxicity, QTc prolongation); however, little is known about clinical effects of very high serum posaconazole serum levels (i.e., ≥ 5000 mg/mL). Reported incidence rate of adverse drug reactions (ADRs) with posaconazole per most recent clinical trial was ∼30%. The primary objective was to compare the ADR incidence in patients with serum posaconazole levels of 3000-4999 ng/mL to ≥5000 ng/mL.

Methods

This retrospective cohort study included adult patients with a posaconazole serum level ≥3000 ng/mL from 1/1/2019 to 04/30/2021. The primary outcome was symptomatic ADR at time of first serum level ≥3000 ng/mL. Secondary outcomes were laboratory defined hepatoxicity, electrolyte and adrenal laboratory abnormalities, QTc changes, and dose changes in response to TDM. Patient outcomes were censored after the first serum level and were compared between groups using Fisher’s exact tests.

Results

Ninety patients met inclusion criteria, 80 with a level of 3000-4999 ng/mL and 10 with a level of ≥ 5000 ng/mL occurring at a median of 91 days (26-443) and 27 days (12-45) from posaconazole initiation, respectively. Majority of patients were immunocompromised (55.6% transplant recipients, 28.9% active malignancy, 5.6% other) with a split of treatment (50%) and prophylaxis (42.2%) indication. Symptomatic ADRs were very common in patients with posaconazole levels of ≥5000 ng/mL and 3000-4999 ng/mL (80% vs. 58.8%; p=0.31), primarily neurologic (49.1% overall) followed by gastrointestinal (32.7% overall). Hepatotoxicity was also common (≥5000 ng/mL 40% vs 3000-4999 ng/mL 23.4%, p=0.26). Fifty percent of patients had the posaconazole dose continued without change. Electrolytes and QTc results were similar between groups, but median overall QTc was borderline high (456 [IQR 435, 479]).

Conclusion

There are safety concerns for patients with serum posaconazole levels ≥3000 ng/mL. Posaconazole levels should be monitored and, importantly, dose adjusted according to serum level and patient symptoms for both treatment and prophylaxis indications.

Disclosures

Christina G. Rivera, PharmD, Gilead: Grant/Research Support|Gilead: Honoraria|Insmed: Honoraria.

Cabotegravir: a novel HIV integrase inhibitor combined with rilpivirine as the first long-acting injectable program for the treatment of HIV infection

Cabotegravir, a novel HIV integrase inhibitor, shares structural similarity with dolutegravir and bictegravir. Its oral half-life is 32 hours, but cabotegravir nanosuspension for intramuscular injection yields half-lives ranging from 25 to 54 days, enabling extended interval dosing. Drug interactions are minimal, although oral doses require spacing from polyvalent cations, and potent uridine glucuronosyltransferase induction (e.g., rifampin, carbamazepine) requires avoidance due to anticipated subtherapeutic cabotegravir exposure through extended intervals. Randomized clinical trials combined cabotegravir treatment with rilpivirine to demonstrate treatment efficacy in patients living with HIV who had attained virologic suppression, lacked known/suspected mutations to either component, and had not experienced prior HIV treatment failure. Together, oral cabotegravir and rilpivirine maintained viral suppression in the LATTE study while the combination, given intramuscularly, performed comparably to conventional oral therapy in LATTE-2. FLAIR and ATLAS, respectively, demonstrated HIV suppression maintenance for monthly injections in treatment-naive participants and treatment-experienced patients, with ATLAS-2M supporting the efficacy of injections given every 2 months. Investigations to date show an excellent safety profile. Injectable cabotegravir causes short-lived, mild injection site reactions (primarily administration site pain/soreness) that decrease in frequency over time, produce attributable discontinuation rates of at least 2%, and generate satisfaction scores that favor injectable therapy over oral therapy. Virologic failure with resistance development is rare, primarily occurs in the first year of therapy, and is associated with baseline proviral DNA mutations to coadministered rilpivirine. A key component of the first U.S. Food and Drug Administration (FDA)-approved injectable maintenance treatment program for HIV, injectable cabotegravir heralds a new era in HIV treatment innovation. Here we provide a detailed review of the clinical pharmacology, administration and available formulations of the novel HIV integrase inhibitor cabotegravir with in-depth analysis of the clinical trial data, safety, satisfaction and viral resistance development when combined with rilpivirine as the first long-acting injectable program for the treatment of HIV infection.

Multiple Simultaneous Infections with Nontuberculous Mycobacteria in the Setting of GATA2 Mutation and Myelodysplastic Syndrome

GATA2 mutation can result in profoundly reduced monocytes, dendritic cells, natural killer cells, and B cells, and is associated with a predisposition for recurrent and disseminated nontuberculous mycobacterial (NTM) infections and myelodysplasias. Herein, we describe a unique case of 3 simultaneous disseminated NTM infections in a patient with GATA2 mutations.

Twice as Nice: Cytomegalovirus Tele-Education

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A Bundle of the Top 10 OPAT Publications in 2021

As outpatient parenteral antimicrobial therapy (OPAT) becomes more common, it may be difficult to stay current with recent related publications. A group of multidisciplinary OPAT clinicians reviewed and ranked all OPAT publications published in 2021. This article provides a high-level summary of the OPAT manuscripts that were voted the “top 10” publications of 2021.

Survey of pharmacists on their roles and perceptions of outpatient parenteral antimicrobial therapy in the United States

OBJECTIVES

To define outpatient parenteral antimicrobial therapy (OPAT) clinical pharmacy practice across the United States, specifically pharmacist functions, design of pharmacist involvement, and to compare pharmacist training of those who practice in OPAT to infectious diseases pharmacists who do not.

METHODS

A survey of a possible 32 questions was emailed to the American College of Clinical Pharmacists (ACCP) Infectious Diseases Practice and Research Network (PRN) e-mail list. Results were focused on US-based respondents.

PARTICIPANTS

In total, 87 pharmacists responded; 27 of these pharmacists (31%) practiced in OPAT.

RESULTS

Training background did not differ between groups. Programs with an OPAT pharmacist were more likely to have a formal OPAT team compared to those without an OPAT pharmacist (P < .001). OPAT pharmacists were early in their careers with 66.7% practicing <5 years in OPAT. Most OPAT pharmacists (66.7%) practiced at an academic medical center with a median full-time equivalent (FTE) of 0.6. Moreover, 63% utilized a collaborative practice agreement and 81.5% shared job functions with other pharmacist roles, most commonly antimicrobial stewardship. Few OPAT programs involved a dispensing component (28%). The median daily census was 43 patients followed by an OPAT pharmacist. Pharmacists performed a variety of tasks in OPAT.

CONCLUSION

Pharmacist nondispensing involvement in OPAT is an emerging trend in the United States with wide variability in program structure and pharmacist tasks. A ratio of 1 OPAT pharmacist for every 45-70 OPAT patients is proposed to facilitate expansion of pharmacist clinical practice in OPAT.

Observational study of the clinical utility of sulfamethoxazole serum level monitoring in the treatment of brain abscesses due to Nocardia species

Although there is a lack of data in trimethoprim-sulfamethoxazole (TMP-SMX) serum monitoring utility for invasive nocardial infections, therapeutic drug monitoring is widely used to optimize dosing and avoid adverse reactions that may cause treatment interruption.We retrospectively reviewed all adults who received TMP-SMX to treat nocardial brain abscess and had SMX serum level testing from 2010 to 2020.Twenty-two patients received treatment with TMP-SMX for Nocardia species brain abscess and 16 (72.7%) had a reported SMX level, with a median patient age of 65.5 years (interquartile range, IQR 59.5-72.5). Compared to those who did not have a documented SMX serum level, patients with SMX levels had a shorter median course of TMP-SMX treatment (322 days [IQR 188-365] vs. 365 [IQR 224-365]; P = .31) and higher therapeutic induction dose (10 [62.5%] vs. 3 [50%]; P = .92). Similarly, they were more frequently on hemodialysis (3 [13.6%] vs. 1 [4.5%]; P = > .99). The median peak level was 158.5 (IQR 120-218) μg/mL, collected at 2 hours (75%) post-administration in the induction phase (81.3%). Patients with documented SMX levels had fewer reported drug toxicity (5 [31.3%] vs. 4 [66.7%]; P = .1) than those without SMX levels. Among the five patients who reported TMP-SMX-related toxicity, 4 (80%) had an SMX peak level >150 μg/mL. There was no difference in the cure, relapse, and death rates among the two groups.While SMX level was not associated with Nocardia species brain abscess cure rates and mortality, most patients with SMX peak >150 μg/mL experienced drug toxicity.

Understanding and Application of Daptomycin-Susceptible Dose-Dependent Category for Enterococcus: A Mixed-Methods Study

Background

In 2018, the Clinical Microbiology Laboratory at our institution adopted updated daptomycin Enterococcus–susceptible dose-dependent breakpoints. While the introduction of susceptible dose-dependent (SDD) was intended to guide practice toward optimal dosing, the understanding and application of daptomycin SDD breakpoints for enterococci were unknown.

Methods

This mixed-methods study combined a clinician survey with a retrospective pre–post prescribing analysis. An 8-question survey was distributed to infectious diseases (ID) and internal medicine (IM) clinicians. A retrospective chart review of hospitalized adults with infections due to Enterococcus spp. was conducted before (pre-SDD) and after (post-SDD) adoption of SDD reporting for enterococci.

Results

Survey response rates were 40 of 98 (41%) for IM and 22 of 34 (65%) for ID clinicians. ID clinicians scored significantly higher than IM clinicians in knowledge of SDD. Chart review of 474 patients (225 pre- vs 249 post-SDD) showed that daptomycin dosage following susceptibility testing was significantly higher post-SDD compared with pre-SDD (8.5 mg/kg vs 6.4 mg/kg; P < .001) with no difference in empiric dosing (6.3 mg/kg vs 6.2 mg/kg; P = .67). Definitive daptomycin use varied between the pre- and post-SDD periods (35.1% vs 16.9%; P < .001).

Conclusions

The survey revealed that ID clinicians placed more importance on and had more confidence in the SDD category over IM clinicians. SDD reporting was associated with a change in definitive daptomycin dosing. ID specialist involvement is recommended in the care of infections due to enterococci for which daptomycin is reported as SDD given their expertise.

1198. Lyme Disease Post-Exposure Prophylaxis by Single-Dose Doxycycline in Three Healthcare Systems

Background

Lyme disease, the most common tickborne disease in the United States, may be prevented by taking a single 200-mg dose of oral doxycycline after a high-risk bite from a blacklegged tick. Currently, it is not known how Lyme disease post-exposure prophylaxis (PEP) might vary by region and healthcare system. We identified single-dose doxycycline medication orders in three healthcare systems in states with high incidence of Lyme disease and compared associated patient and provider characteristics.

Methods

Electronic health record data during 2012 – 2016 were obtained from three healthcare systems: Geisinger (Pennsylvania), Marshfield Clinic (Wisconsin), and Mayo Clinic (Minnesota/Wisconsin). Creation of analytic variables and analysis were harmonized across the three sites. Medication orders for single-dose doxycycline ≤200 mg that were accompanied by specific key words or diagnostic codes (e.g., tick bite; Lyme disease prevention) were considered evidence of PEP. Manual chart review was performed from a random subset to evaluate the algorithms used to identify PEP.

Results

Among 2,937,585 patients with at least one medication order or clinical encounter during the study period, 14,102 single-dose doxycycline orders for Lyme disease PEP for 13,172 unique patients were identified. The typical patient receiving PEP was older (mean age 51 – 58 years), male (56 – 59%), and non-Hispanic White (81 – 98%). The annual seasonality of medication orders was bimodal, with peaks occurring during April – July and October – November. The most common encounter setting was an outpatient clinic or urgent care center (80 – 91%); medication orders after patient phone calls in the absence of an in-person visit occurred frequently (14 – 19%) in two health systems. Chart abstractions (n=600) revealed instances of PEP prescribed inappropriately (e.g., bite from a non-blacklegged tick; patient with symptoms of acute Lyme disease).

Conclusion

Lyme disease PEP with a single dose of doxycycline was frequently prescribed in healthcare systems where there is a high incidence of Lyme disease. PEP was most commonly prescribed to non-Hispanic Whites over the age of 50 years. Public health initiatives for tickborne disease prevention should include clinician education on the appropriate use of Lyme disease PEP.

Disclosures

Anna M. Schotthoefer, PhD, HelixBind (Other Financial or Material Support, salary support) John Zeuli, PharmD, INSMED (Other Financial or Material Support, honoraria for educational speaking)

619. Current State of Infectious Diseases Pharmacist OPAT/COpAT Practice in the United States

Background

Outpatient parenteral antimicrobial therapy (OPAT) is the process of administering intravenous (IV) antimicrobials outside the acute inpatient setting. Oral antimicrobials for complex infections are referred to as complex outpatient antimicrobial therapy (COpAT). OPAT/COpAT programs are expanding, as are the opportunities for clinical Infectious Diseases (ID) pharmacists (RPHs) involvement. The current state of clinical (non-dispensing) role and the functions being performed by RPHs in OPAT/COpAT is unknown.

Methods

To define the current state of OPAT/COpAT pharmacy practice across the United States (US), specifically the clinical functions performed by RPHs, design of RPH involved OPAT/COpAT clinics, and compare training of RPHs who practice in OPAT/COpAT to ID RPHs who do not, a survey of a possible 31 questions was emailed to the American College of Clinical Pharmacists (ACCP) Infectious Diseases Practice and Research Network (PRN) email list. Results were focused on US-based respondents.

Results

Eighty-seven RPHs responded with 27 practicing in OPAT/COpAT. Training background did not differ between groups. Programs with an OPAT/COpAT RPH were more likely to have a formal OPAT team compared to those without an OPAT/COpAT RPH (p &lt; 0.001). OPAT/COpAT RPHs were early in their careers, with roughly half practicing &lt; 5 years in ID, and 66.7% practicing &lt; 5 years in OPAT/COpAT. Most OPAT/COpAT RPHs (66.7%) practiced at an academic medical center with a median full time equivalent (FTE) of 1 RPH. Most (63%) utilized a collaborative practice agreement and 81.5% shared job functions with other ID RPH roles, most commonly antimicrobial stewardship. Few (28%) OPAT/COpAT programs involved a dispensing component. The average daily census was 42 patients followed by an OPAT/COpAT RPH. There was wide variability in the types of tasks ID RPH performed in OPAT/COpAT, the three most important tasks are listed in Figure 1.

OPAT Pharmacists Task Ranking by Importance

Conclusion

This is the largest known survey of OPAT/COpAT RPHs. RPH involvement in OPAT/COpAT in the US is an emerging trend with wide variability in program structure. Tasks performed by OPAT/COpAT RPHs varied significantly; however, OPAT/COpAT RPH respondents’ functions are largely clinical in nature.

Disclosures

All Authors: No reported disclosures

272. Clinical Utility of Sulfamethoxazole Serum Level Monitoring in the Treatment of Brain Abscesses due to Nocardia Species

Background

Although trimethoprim-sulfamethoxazole (TMP-SMX) has consistently demonstrated significant interindividual variability, therapeutic drug monitoring is used to optimize dosing and avoid adverse reactions that may contribute to treatment interruption. While data exists on the use of SMX level monitoring in pneumocystis, there is a lack of data in SMX serum monitoring utility for invasive Nocardia infections.

Methods

We retrospectively reviewed adults who received TMP-SMX to treat nocardial brain abscess (BA) and underwent SMX testing level from January 2010 to December 2020.

Results

Overall, 24 patients had Nocardia spp. BA; Twenty-two (91.7%) were treated with TMP-SMX, and 16/22 (72.7%) had a documented SMX serum level. The median age was 64 (IQR 58-69) years, and the majority were males (77.3%). Compared to those who did not have a documented SMX serum level, patients with SMX levels had a higher prevalence of hemodialysis (HD, 42.9% vs. 33%; P=.99) and malignancy (50% vs. 33.3%; P=.65). The most common BA location was the frontal lobe (43.8% vs. 33.3%; P=.99), with a single (68.8% vs. 50%; P=.62) and smaller (1.3 vs. 1.9 cm; P=.58) brain fluid collection, and with fewer midline shift (6.3% vs. 16.7%; P=.48), respectively. The median TMP-SMX duration was 350 days (P=.31). The most common dosing was 2-double strength, three times a day (31.8%). The SMX median level was 158.5 (IQR 120-218) mcg/mL, collected at two hours (75%) post-administration in the induction phase (81.3%). The most common recommendation was to continue therapy based on the level results. Eleven (46%) patients had a level &gt;150 mcg/mL, and 5 (45.5%) reported drug toxicity, including nausea in 3, acute kidney injury in 2, and thrombocytopenia in 2 patients. Ninety-four percent of the patients with SMX levels had surgical intervention for therapeutic purposes vs. 83% of those without it (P=.65). A total of 11 (50%) patients were cured, 3 (18.8%) relapsed, and 2 (12.5%) died.

Conclusion

Patients with SMX serum level monitoring are more likely to be on HD, during the induction phase and among those with higher and more frequent dosing. About half of patients with SMX levels &gt;150 mcg/mL experienced drug toxicity; however, SMX levels did not impact patient outcome and length of treatment.

Disclosures

All Authors: No reported disclosures

Single center, open label dose escalating trial evaluating once weekly oral ixazomib in ART-suppressed, HIV positive adults and effects on HIV reservoir size in vivo

BACKGROUND

Achieving a functional or sterilizing cure for HIV will require identification of therapeutic interventions that reduce HIV reservoir size in infected individuals. Proteasome inhibitors, such as ixazomib, impact multiple aspects of HIV biology including latency, transcription initiation, viral replication, and infected cell killing through the HIV protease - Casp8p41 pathway, resulting in latency reversal and reduced measures of HIV reservoir size ex vivo.

METHODS

We conducted a phase 1b/2a dose escalating, open label trial of weekly oral ixazomib for 24 weeks in antiretroviral (ART)-suppressed, HIV positive adults (NCT02946047). The study was conducted from March 2017 to August 2019 at two tertiary referral centers in the United States. The primary outcomes were safety and tolerability of oral ixazomib. Secondary outcomes included changes in immunologic markers and estimates of HIV reservoir size after ixazomib treatment.

FINDINGS

Sixteen participants completed the study. Ixazomib up to 4mg weekly was safe and well-tolerated, yielding no treatment-emergent events above grade 1. In exploratory analyses, ixazomib treatment was associated with detectable viremia that was below the lower limit of quantification (LLQ) in 9 participants, and viremia that was above LLQ in 4 of 16 participants. While treatment was associated with reduced CD4 counts [baseline 783 cells/ mm³ vs. week-24 724 cells/ mm³ p=0.003], there were no changes in markers of cellular activation, exhaustion or inflammation. Total HIV DNA and proviral sequencing were not altered by ixazomib treatment. Intact proviral DNA assay (IPDA) identified intact proviruses in 14 patients pre-treatment, and in 10/14 of those subjects post treatment values were reduced (P=0.068), allowing a calculated intact proviral half life of 0.6 years (95% CI 0.3, 2.5), compared to 7.1 years (95% CI 3.9, 18, p=0.004) in historical controls. Differentiation Quantitative Viral Outgrowth Assays (dQVOA) identified measurable proviruses in 15 subjects pre-treatment; post-treatment values were numerically reduced in 9, but overall differences were not significantly different.

INTERPRETATION

Our study successfully met its primary endpoint of demonstrating the safety of ixazomib for 24 weeks in HIV infected persons. Exploratory analyses suggest that the effects observed ex vivo of latency reversal and reductions in HIV reservoir size, also occur in vivo. Future controlled studies of ixazomib are warranted.

FUNDING

This study was funded by Millennium Pharmaceuticals Inc..; the Mayo Clinic Foundation; the National Institutes of Health, including the National Institute of Allergy and Infectious Diseases, Division of AIDS, the National Heart, Lung and Blood Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institute of Neurological Disorders and Stroke, and the National Institute on Drug Abuse. Mayo Clinic also acknowledges generous funding support from Mr. Joseph T. and Mrs. Michele P. Betten.

Hepatotoxicity of contemporary antiretroviral drugs

PURPOSE OF REVIEW

To date, more than 30 antiretroviral drugs have been approved by the Food and Drug Administration for the treatment of HIV infection. As new drugs with better efficacy and safety profile become available for clinical practice, older drugs are either withdrawn from the market or become no longer actively prescribed. We review hepatotoxicity associated with contemporary antiretroviral drugs, with emphasis on data from the past 3 years.

RECENT FINDINGS

Although less robust data exists for side effects of contemporary antiretroviral medications recently approved for the management of HIV (i.e., doravirine, ibalizumab, fostemsavir, cabotegravir), the risks of substantial hepatotoxicity appears to be minimal with these agents.

SUMMARY

Although newer antiretroviral drugs are better tolerated than their earlier counterparts, they are not completely devoid of adverse drug reactions, including hepatotoxicity. Monitoring patients on antiretroviral therapy for treatment-emergent liver injury should continue to be part of routine clinical care.

Unexpected Vancomycin Pharmacokinetic Profile Secondary to Macromolecular Complexing: A Case Series

BACKGROUND

The optimal dosing and monitoring of vancomycin has been largely debated for decades, with key guideline changes for recommended monitoring in 2009 and 2020. Current and past practices for pharmacokinetic dose optimization use serum drug assays to guide dose adjustment to effectively balance efficacy and the risks of toxicity. These assays detect both bound and unbound serum concentrations. Vancomycin is believed to be 50%-55% protein bound in most cases; however, some variability in this parameter has been previously published. The authors report 2 cases of abnormal vancomycin pharmacokinetics discovered based on unexpected serum levels during routine clinical care.

METHODS

Unexpected vancomycin levels, observed during clinical care for 2 separate patients, were further evaluated to determine the source of the abnormal pharmacokinetics. In case 1, serial dilution was performed to assure that assay interference was not associated with the significant elevation (>100 mg/L). In both cases, samples were filtered using a Millipore Centrifree 30 KDa centrifugal filter to separate bound vancomycin, with a Protein G spin kit used to bind IgG and remove IgG complexes from the patient sample. In case 2, a polyethylene glycol precipitation was also performed to precipitate large-molecular-weight complexes.

RESULTS

In both cases, laboratory analysis revealed abnormal vancomycin protein-binding profiles with macromolecular complex formation. Immunoglobulin G played a role in the macrocomplex in both patients.

CONCLUSIONS

In cases of unusual or unexpected vancomycin pharmacokinetics in the absence of renal dysfunction, an abnormal protein-binding profile should be considered. Bound vancomycin may yield elevated serum levels, leading to poorly informed dose adjustments and risk for treatment failure. Given implications for therapeutic drug monitoring and unknown impacts on efficacy and toxicity, further investigations into population incidence and risk factors for abnormal protein binding of vancomycin are warranted.

Call to Pharmacists: End Use of "Red Man Syndrome"

Red Man Syndrome is a term used for an adverse event attributed to vancomycin infusion. Based on the presentation within white patients, the term is imprecise at best and can lead to suboptimal classification and management. Recent calls have advocated for the discontinuation of the use of this terminology. Pharmacists should take the lead in advocating for this change.

Cefazolin and rifampin: A coagulopathy-inducing combination

PURPOSE

To identify risk factors that may predispose patients to rifampin- and cefazolin-induced coagulopathy.

SUMMARY

An 86-year-old man with a history of rheumatoid arthritis on chronic prednisone and stage 3 chronic kidney disease, notably not on warfarin, presented to the hospital with a 10-day history of right hip pain, swelling, and drainage after a recent right total-hip arthroplasty. The patient underwent a combination of surgical intervention and medication therapy with rifampin and ceftriaxone. After discharge and at postoperative day 9, ceftriaxone was changed to cefazolin due to increasing alkaline phosphatase levels. Four weeks after the initial debridement, antibiotics, and implant retention, the patient underwent a second irrigation and debridement due to persistent infection. Cefazolin and rifampin therapy was extended. Three days later, the patient presented to the emergency room with significant bleeding at the surgical site and a profoundly elevated prothrombin time and international normalized ratio (INR). No potential contributors were identified. The Naranjo adverse drug reaction probability scale identified cefazolin and rifampin as the probable cause of elevated INR. The Liverpool adverse drug reaction avoidability assessment tool classified this adverse event as "definitely avoidable."

CONCLUSION

Rifampin-containing regimens are often recommended to treat staphylococcal prosthetic joint infections when the implant is retained. In methicillin-susceptible staphylococcal infections, cefazolin is routinely employed as the β-lactam backbone of definitive antimicrobial regimens. Although rifampin- and cefazolin-induced hypoprothrombinemia seems to be rare, adverse consequences of its occurrence may be prevented with appropriate monitoring.

Approach to the diagnosis and treatment of non-tuberculous mycobacterial disease

Non-tuberculous mycobacteria (NTM) is a collective name given to a group of more than 190 species of Mycobacterium. The clinical presentation for most NTM infections is non-specific, often resulting in delayed diagnosis. Further complicating matters is that NTM organisms can be difficult to isolate. Medications used to treat NTM infection can be difficult for patients to tolerate, and prolonged courses of anti-mycobacterial therapy are often required for adequate suppression or eradication. Herein, we review different NTM syndromes, appropriate diagnostic tests, and treatment regimens.

Safety and tolerability of liquid amikacin in antibiotic-loaded bone cement - a case series

High-dose liquid antibiotics are uncommon in bone cement. We present a case series of patients in which up to 16 mL of liquid amikacin (250 mg mL-1) was successfully incorporated into bone cement to treat periprosthetic joint infections. We did not observe adverse drug reactions definitively attributed to its use.

Novel Use of Rifabutin and Rifapentine to Treat Methicillin-Resistant Staphylococcus aureus in a Rat Model of Foreign Body Osteomyelitis

BACKGROUND

Owing to patient intolerance or drug interactions, alternative agents to rifampin are needed for management of staphylococcal periprosthetic joint infection. In the current study, we evaluated rifabutin, rifapentine and rifampin, with and without vancomycin, in a rat model of foreign body osteomyelitis.

METHODS

Proximal tibiae were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and a Kirschner wire (K-wire) implanted in each. After 4 weeks of infection, rifampin, rifabutin, or rifapentine were administered, alone or with vancomycin. Tibiae and K-wires were cultured, and medians were reported as log10 colony-forming units (CFUs) per gram of bone or log10 CFUs per K-wire, respectively.

RESULTS

Rifampin, rifabutin or rifapentine administered with vancomycin yielded less MRSA from bones (0.10, 3.02, and 0.10 log10 CFUs/g, respectively) than did no treatment (4.36 log10 CFUs/g) or vancomycin alone (4.64 log10 CFUs/g) (both P ≤ .02). The K-wires of animals receiving no treatment or vancomycin monotherapy recovered medians of 1.76 and 2.91 log10 CFUs/g per K-wire, respectively. In contrast, rifampin, rifabutin and rifapentine administered with vancomycin yielded medians of 0.1 log10 CFUs per K-wire, respectively. Rifampin resistance was detected in a single animal in the rifampin monotherapy group.

CONCLUSIONS

Rifabutin or rifapentine with vancomycin were as active as rifampin with vancomycin against MRSA in rat foreign body osteomyelitis, suggesting that rifabutin and/or rifapentine may be alternatives to rifampin in the clinical management of staphylococcal periprosthetic joint infections.

Safety and Tolerability of Fluoroquinolones in Patients with Staphylococcal Periprosthetic Joint Infections

BACKGROUND

Fluoroquinolones (FQs) are known to be accompanied by significant risks. However, the incidence of adverse events (ADE) resulting in unplanned drug discontinuation when used for periprosthetic joint infections (PJI) is currently unknown.

METHODS

This study included 156 patients over the age of 18 treated for staphylococcal PJI with debridement, antibiotics, and implant retention (DAIR), between January 1, 2007 and November 21, 2019. Of the 156 patients, 64 had total hip arthroplasty (THA) and 92 had total knee arthroplasty (TKA) infections. The primary outcome was rate of unplanned drug discontinuation. Secondary outcomes included incidence of severe ADE, unplanned rifamycin discontinuation, mean time to unplanned regimen discontinuation, and all-cause mortality.

RESULTS

Overall, unplanned drug discontinuation occurred in 35.6% of patients in the FQ group and 3% of patients in the non-FQ group. The rate of unplanned discontinuation of FQ regimens as compared to non-FQ regimens was 27.5% vs 4.2% (p=0.021) in THA infections and 42% vs 2.4% (p<0.001) in TKA infections. There was no significant difference in severe ADEs between FQ and non-FQ regimens in both THA and TKA infections. The overall rate of non-severe ADEs in FQ compared to non-FQ regimens was 43.3% vs 6.1% (p<0.001). FQs were associated with tendinopathy, myalgia, arthralgia, and nausea.

CONCLUSIONS

A significantly higher rate of unplanned drug discontinuation was associated with FQ as compared to non-FQ regimens. This provides a real-world view of the implications of FQ related adverse events on unplanned discontinuation when used in prolonged durations for the management of staphylococcal PJIs.