Subcutaneous Antibiotic Therapy: The Why, How, Which Drugs and When

Challenges of antimicrobial stewardship among older adults

Older adults hospitalized in internal medicine wards or long-term care facilities (LTCF) are progressively increasing. Older adults with multimorbidity are more susceptible to infections, as well as to more vulnerable to adverse effects (and interactions) of antibiotics, resulting in a need for effective and safer strategies for antimicrobial stewardship (ASM), both in hospitalization wards and long-term care facilities. Studies on antimicrobial stewardship in older patients are scarce and guidelines are required. Given the peculiarities of the optimization of antimicrobial prescription in individual older adults for common infections, tactics to overcome barriers need an update. The use of rapid diagnosis tests, biomarkers, de-escalation and switching from intravenous to oral/subcutaneous therapy strategies are examples of successful AMS interventions. AMS interventions are associated with reduced side effects, lower mortality, shorter hospital stays, and reduced costs. The proposed AMS framework in LTCF should focus on five domains: strategic vision, team, interventions, patient-centred care and awareness. Internists can partner with geriatrists, pharmacists and infectious disease specialists to address barriers and to improve patient care.

Short subcutaneous infusions for symptom control in palliative medicine

OBJECTIVES

To investigate the efficacy and safety of short subcutaneous infusions (SSCIs) for refractory symptoms in the palliative setting.

METHODS

A retrospective chart review of SSCIs in a single palliative care centre over an 18-month period. All clinical notes, medication administration records and infusion monitoring documentation were examined to ascertain therapeutic aim, efficacy and tolerability.

RESULTS

111 patients received one or more SSCIs, 28 in the community and 83 in the inpatient hospice (21% of all admissions). SSCIs were used for a wide variety of reasons including loading doses (to achieve steady state and, thus, symptom relief, sooner), as required doses (for medications too irritant to give as bolus SC injections) and regular maintenance doses (where continuous subcutaneous infusion (CSCI), were unnecessary). 84 single drug SSCIs types and 51 admixtures SSCIs types (2 or more medications) were given. One infusion was poorly absorbed, but SSCIs were otherwise well tolerated.

CONCLUSIONS

SSCIs appear to be a promising additional option for administering medicines that are too irritant or large in volume for SC bolus injection. For medications with longer half-lives (eg, phenobarbital, valproate, levetiracetam), SSCI loading doses would be expected to achieve steady state and, thus, symptom relief, sooner than CSCIs alone.

Safety of subcutaneous versus intravenous ceftriaxone administration in older patients: A retrospective study

BACKGROUND

Antibiotics play a central role in infection management. In older patients, antibiotics are frequently administered subcutaneously. Ceftriaxone pharmacokinetics after subcutaneous administration is well documented, but little data are available on its safety.

METHODS

We compared the occurrence of adverse events associated with ceftriaxone administered subcutaneously versus intravenously in ≥75-year-old patients. We used data from a single-center, retrospective, clinical-administrative database to compare the occurrence of adverse events at day 14 and outcome at day 21 in older patients who received ceftriaxone via the subcutaneous route or the intravenous route at Rennes University Hospital, France, from May 2020 to February 2023.

RESULTS

The subcutaneous and intravenous groups included 402 and 3387 patients, respectively. Patients in the subcutaneous group were older and more likely to receive palliative care. At least one adverse event was reported for 18% and 40% of patients in the subcutaneous and intravenous group, respectively (RR = 2.21). Mortality at day 21 was higher in the subcutaneous route group, which could be linked to between-group differences in clinical and demographic features.

CONCLUSIONS

In ≥75-year-old patients, ceftriaxone administered by the subcutaneous route is associated with less-adverse events than by the intravenous route. The subcutaneous route, which is easier to use, has a place in infection management in geriatric settings.

Empirical antibiotic therapy modalities for Enterobacteriaceae bloodstream infections in older patients and their impact on mortality: a multicentre retrospective study

PURPOSE

Enterobacteriaceae (EB) bloodstream infections (BSI) are frequent and serious in older patients. Physicians are faced with the dilemma of prescribing early appropriate empirical antibiotics to limit the risk of death, and sparing broad-spectrum antibiotic prescription. The aim of the study was to assess the rate of appropriate empirical antibiotics prescription to treat EB BSI in older patients and its impact on survival.

METHODS

This study conducted in 49 centres enrolled retrospectively up to the 10 last consecutive patients aged 75 years and over and treated for EB BSI. Factors related to in-hospital death were investigated using logistic regression.

RESULTS

Among the 487 enrolled patients (mean age 86 ± 5.9 years), 70% had at least one risk factor of being infected by third-generation cephalosporins (3GC)-resistant strain; however, only 13.8% of EB strains were resistant to 3GC. An empirical antimicrobial treatment was initiated for 418 patients (85.8%), and for 86% (n = 360/418) of them, it was considered appropriate. In-hospital mortality was 12.7% (n = 62) and was related to the severity of infection (OR 3.17, CI 95% 1.75-5.75), while a urinary portal of entry was protective (OR 0.34, CI 95% 0.19-0.60). Neither the absence of nor inappropriate empirical antibiotics prescription was associated with increased mortality.

CONCLUSION

While patients enrolled in this study were at risk of being infected by multidrug-resistant bacteria, yet mainly treated with 3GC, empirical antibiotics prescription was appropriate in most cases and did not influence mortality.

The Subcutaneous Administration of Beta-Lactams: A Case Report and Literary Review-To Do Small Things in a Great Way

The subcutaneous (s.c.) route is a commonly used method for delivering various drugs, although its application in the administration of antibiotics is relatively uncommon. In this case, we report a successful treatment of nosocomial pneumonia using piperacillin/tazobactam via continuous subcutaneous administration. Furthermore, this article provides an overview of the current literature regarding the s.c. administration of beta-lactam antibiotics. Based on our analysis, we identified only 15 studies that described the s.c. use of beta-lactam antibiotics in human subjects. Among these studies, cephalosporins were the most extensively investigated antibiotic class, with 10 available studies. According to the study findings, all three antibiotic classes (cephalosporins, penicillins, and carbapenems) demonstrated a similar pharmacokinetic profile when administered via the subcutaneous route. The subcutaneous route appears to be associated with a lower peak serum concentration (Cmax) but a comparable minimum blood concentration (Cmin) and an extended half-life (t1/2) when compared to conventional routes of antibiotic administration. Further research is necessary to determine whether subcutaneously administered beta-lactam antibiotics in human subjects achieve pharmacodynamic targets and demonstrate clinical efficacy.

Effectiveness of Subcutaneous Administration of Antibiotics to Control Infections in Elder Palliative Patients: A Systematic Review

Background: Infections are common in patients with advanced illnesses for whom the intravenous or oral route is not possible. The subcutaneous administration of antibiotics is a promising alternative, but there is not enough theoretical support for its use. This study aims to explore the effectiveness and safety of subcutaneous antibiotic therapy in the context of palliative care in elderly patients. Methods: A systematic review was conducted using PubMed and Embase, without time or language limits. Seven articles were selected on the effectiveness of subcutaneous antibiotic therapy in adult patients with chronic progressive diseases. The quality of the articles was assessed with the Newcastle Ottawa Scale and relevant data was extracted using a selection capture file. Results: Seven quasi-experimental studies evaluated 865 elderly patients with advanced diseases, comorbidities, and infections (ie, urinary tract, respiratory system, and bone joint) who received subcutaneous antibiotic therapy (ie, Ceftriaxone, Ertapenem, and Teicoplanin). The pooled success rate of subcutaneous antibiotics for the 7 studies was 71%, the therapy failure rate was 22%, its withdrawal mean was 8%, and the mean mortality rate was 7%. The studies were of low quality and were heterogeneous in the types of infections, types of antibiotics, time of follow-up, and outcomes assessed. Conclusions: Pilot studies have found a limited number of antibiotics that can be safely used to treat specific infections. Nevertheless, the data isn´t robust enough to recommend their use.

[Rules of good practice for the elderly]

The treatment of infectious diseases in geriatric medicine is a complex subject. Diagnosis is often difficult, as is the correct indication for antibiotic therapy. To combat antibiotic resistance, we need to limit unnecessary antibiotic prescriptions and prevent the onset of bacterial infections, notably through vaccination.

International Consensus Recommendation Guidelines for Subcutaneous Infusions of Hydration and Medication in Adults: An e-Delphi Consensus Study

Infusion of fluids and medications is traditionally performed intravenously. However, venous depletion in patients has led to the quest for vessel health preservation. A safe, effective, acceptable, and efficient alternative is the subcutaneous route. A lack of organizational policies may contribute to the slow uptake of this practice. This modified e-Delphi (electronic) study aimed to derive international consensus on practice recommendations for subcutaneous infusions of fluids and medications. A panel of 11 international clinicians, with expertise in subcutaneous infusion research and/or clinical practice, rated and edited subcutaneous infusion practice recommendations from evidence, clinical practice guidelines, and clinical expertise within an Assessment, Best Practice, and Competency (ABC) domain guideline model. The ABC Model for Subcutaneous Infusion Therapy provides a systematic guideline of 42 practice recommendations for the safe delivery of subcutaneous infusions of fluids and medications in the adult population in all care settings. These consensus recommendations provide a guideline for health care providers, organizations, and policy makers to optimize use of the subcutaneous access route.

Subcutaneously administered antibiotics: a review

BACKGROUND

Subcutaneous (SC) administration of antibiotics represents an attractive alternative to the intravenous (IV) route.

METHODS

We performed a systematic electronic search of PubMed and the Cochrane Library for all articles published prior to April 2022, using the key terms and MeSH terms 'subcutaneous', 'antibiotic' and the international non-proprietary name of antibiotics.

RESULTS

A total of 30 studies were selected including data on the efficacy and tolerability of antibiotics, and seven studies that were conducted in healthy subjects, for relevant information regarding the safety and tolerability of antibiotics. Comparative studies have shown that efficacy is similar for the SC and IV routes for ceftriaxone, teicoplanin and ertapenem. The SC use of other antibiotics such as ampicillin, ceftazidime, cefepime, piperacillin/tazobactam, metronidazole and fosfomycin has also been described. These results have largely been corroborated by pharmacokinetic/pharmacodynamic analyses, especially for time-dependent antibiotics. Complications of SC treatment are rarely severe, with no reports of bacteraemia or other invasive infection related to this route of administration. Therapeutic drug monitoring has been proposed to adapt the dose and avoid toxicity.

DISCUSSION

The rationale for using SC administration of ceftriaxone, ertapenem and teicoplanin is strong in patients with non-severe infections. It is already commonly practised in some countries, particularly in France. Other antibiotics could be administered subcutaneously, but further studies are needed to validate their use in clinical practice. Further research is needed to safely generalize and optimize this route of administration whenever possible. This would reduce the risk of catheter-related infections and their complications, together with the length of hospital stay.

Development of an In Vitro System To Emulate an In Vivo Subcutaneous Environment: Small Molecule Drug Assessment

A reliable in vitro system can support and guide the development of subcutaneous (SC) drug products. Although several in vitro systems have been developed, they have some limitations, which may hinder them from getting more engaged in SC drug product development. This study sought to develop a novel in vitro system, namely, Emulator of SubCutaneous Absorption and Release (ESCAR), to better emulate the in vivo SC environment and predict the fate of drugs in SC delivery. ESCAR was designed using computer-aided design (CAD) software and fabricated using the three-dimensional (3D) printing technique. ESCAR has a design of two acceptor chambers representing the blood uptake pathway and the lymphatic uptake pathway, respectively, although only the blood uptake pathway was investigated for small molecules in this study. Via conducting a DoE factor screening study using acetaminophen solution, the relationship of the output (drug release from the "SC" chamber to the "blood circulation" chamber) and the input parameters could be modeled using a variety of methods, including polynomial equations, machine learning methods, and Monte Carlo simulation-based methods. The results suggested that the hyaluronic acid (HA) concentration was a critical parameter, whereas the influence of the injection volume and injection position was not substantial. An in vitro-in vivo correlation (IVIVC) study was developed using griseofulvin suspension to explore the feasibility of applying ESCAR in formulation development and bioequivalence studies. The developed LEVEL A IVIVC model demonstrated that the in vivo PK profile could be correlated with the in vitro release profile. Therefore, using this model, for new formulations, only in vitro studies need to be conducted in ESCAR, and in vivo studies might be waived. In conclusion, ESCAR had important implications for research and development and quality control of SC drug products. Future work would be focused on further optimizing ESCAR and expanding its applications via assessing more types of molecules and formulations.

Subcutaneous ertapenem delivered by an Australian outpatient parenteral antimicrobial therapy service: a retrospective comparative efficacy study

Subcutaneous (SC) administration of ertapenem in outpatient parenteral antimicrobial therapy (OPAT) services may be a practical alternative to intravenous delivery for complicated infections. The clinical features and outcomes according to route of administration were compared from a large Australian OPAT service. Chronic renal impairment was more common in the SC group, reflecting an opportunity for route of administration as a vein preservation strategy. Adverse events were uncommon and successful outcomes were not different between the groups.

Results of a Dose-Finding Phase 1b Study of Subcutaneous Atezolizumab in Patients With Locally Advanced or Metastatic Non-Small Cell Lung Cancer

Intravenous (IV) atezolizumab is approved for non-small cell lung and other cancers. Subcutaneous (SC) atezolizumab coformulated with recombinant human hyaluronidase, a permeation enhancer for SC dispersion and absorption, is being developed to improve treatment options, reduce burden, and increase efficiency for patients and practitioners. IMscin001 (NCT03735121), a 2-part, open-label, global, multicenter, phase 1b/3 study, is evaluating the pharmacokinetics (PK), safety, and efficacy of SC atezolizumab. The part 1 (phase 1b) objective was determination of an SC atezolizumab dose yielding a serum trough concentration (C_trough ) comparable with IV. Patients enrolled in 3 cohorts received SC atezolizumab 1800 mg (thigh) once (cohort 1), 1200 mg (thigh) every 2 weeks for 3 cycles (cohort 2), or 1800 mg (abdomen) every 3 weeks cycle 1, then cycles 2 and 3 (thigh) every 3 weeks (cohort 3). In subsequent cycles, IV atezolizumab 1200 mg every 3 weeks was administered until loss of clinical benefit. SC atezolizumab 1800 mg every 3 weeks and 1200 mg every 2 weeks provided similar C_trough and area under the curve values in cycle 1 to the corresponding IV atezolizumab reference, was well tolerated, and exhibited a safety profile consistent with the established IV formulation. Exposure following SC injection in the abdomen was lower (20%, 28%, and 27% for C_trough , maximum concentration, and area under the concentration-time curve from time 0 to day 21, respectively) than in the thigh. Part 1 SC and IV PK data were analyzed using a population PK modeling approach, followed by simulations. Part 2 (phase 3) will now be initiated to demonstrate that SC atezolizumab PK exposure is not lower than that of IV.

Outpatient Subcutaneous Antimicrobial Therapy (OSCAT) as a Measure to Improve the Quality and Efficiency of Healthcare Delivery for Patients With Serious Bacterial Infections

Since the 1970s, outpatient parenteral antimicrobial therapy (OPAT) has been a viable option for patients who require intravenous antibiotics when hospitalization is not warranted. While the benefits of OPAT as a measure to improve the efficiency of healthcare delivery (i.e., reduced hospital days) and patient satisfaction are well-documented, OPAT is associated with a number of challenges, including line complications and reliance on daily healthcare interactions in some cases at home or in a clinic. To minimize the continued need for intensive healthcare services in the outpatient setting, there is trend toward patients self-administering antibiotics at home without the presence of healthcare workers, after adequate training. In most cases, patients administer the antibiotics through an established intravenous catheter. While this OPAT practice is becoming more accepted as a standard of care, the potential for line complications still exists. Outpatient subcutaneous antimicrobial therapy (OSCAT) has become an increasingly accepted alternative route of administration of antibiotics to IV by French infectious diseases physicians and geriatricians; however, currently, no antibiotics are approved to be administered subcutaneously. Antibiotics with longer half-lives that are completely absorbed and have a favorable local tolerability profile are ideal candidates for OSCAT and have the potential to maximize the quality and efficiency of parenteral antibiotic delivery in the outpatient setting. The increasing development of wearable, on-body subcutaneous delivery systems make OSCAT even more viable as they increase patient independence while avoiding line complications and potentially removing the need for direct healthcare professional observation.