Designing drug regimens for special intensive care unit populations

'Real-life' approach to applying PK/PD principles in infectious diseases clinical practice without access to prompt TDM

INTRODUCTION

Infectious disease treatments are transitioning from a one-size-fits-all approach to a more tailored approach. The increasing adoption of therapeutic drug monitoring (TDM) of antimicrobials is a clear example of this trend. Routine antimicrobial TDM in critically ill patients should be mandatory. Unfortunately, nowadays, only expert centers can provide it. Given the crucial nature of the first hours/days for achieving a favorable clinical outcome, empirical antibiotic therapy with an adequate choice of drug, dose and administration modalities is fundamental.

AREAS COVERED

We outline common scenarios encountered in clinical practice, such as in edematous patients, hypoalbuminemia, patients with liver and renal diseases, patients under renal replacement therapy or extracorporeal membrane oxygenation (ECMO), over or under-weight patients, in old adults and cases of infections caused by relatively high minimum inhibitory concentration (MIC) pathogens. Various clinical situations were analyzed with the help of the available literature (PubMed/MEDLINE/Google Scholar and books written by experts in pharmacology and infectious diseases).

EXPERT OPINION

In these different scenarios, we reported common examples of optimizing drug utilization to maximize therapeutic outcomes, reduce incorrect prescriptions and limit the emergence of antimicrobial resistance.

Ketamine Use in Adult and Pediatric Patients Receiving Extracorporeal Membrane Oxygenation (ECMO): A Systematic Review

Background: Analgesia and sedation are often critical elements of therapy for patients undergoing extracorporeal membrane oxygenation (ECMO). Aside from potential drug-drug interactions, the PK changes associated with ECMO make appropriate analgosedative selection challenging. Ketamine is less lipophilic and has lower protein binding than alternative agents, and may be less impacted by the PK changes during ECMO. Objective: To systematically identify all instances of ketamine use during ECMO support in the literature to elucidate associated efficacy and safety outcomes and prevalence of use, as well as commonly used dosing strategies and pharmacokinetic data. Methods: Web of Science, Cochrane Library, Scopus, Ovid MEDLINE, PubMed, and OVID Embase were searched through 02/2023 using keywords ketamine and ECMO or extracorporal life support (ECLS). Case reports, case series, and studies were included that had (1) original data, (2) included patients that were on ECMO and continuous infusion ketamine, and (3) reported pertinent ketamine related clinical endpoints or prevalence of use. Results: Of the 307 articles screened, 25 were identified as relevant and 11 met our inclusion criteria. Heterogeneity of patient population, ketamine indication, reported outcomes, and reported safety endpoints were identified in the included articles. Commonly reported information includes indications, pharmacokinetics, dosing, adverse effects and use in pediatrics for ketamine, and suspected opioid sparing effect. Conclusion: Our review has found a lack of consistency in reporting and results in adult and pediatric patients. Increased consistency in reporting and larger studies are required to increase our knowledge of ketamine use in both the adult and pediatric patient population.

Ketamine infusion for sedation in a patient on extracorporeal membrane oxygenation (ECMO)

Introduction: we sought to explore the efficacy of ketamine in a patient on extracorporeal membrane oxygenation (ECMO) receiving ketamine for sedation by investigating the utility of plasma ketamine concentrations.Case report: retrospective chart review of one critically ill patient on ECMODiscussion: This was a descriptive review of serial plasma ketamine concentrations in an ECMO patient. Although no reference plasma concentrations exist in ECMO patients, ketamine levels appeared to be lower than those seen in surgical patients not on ECMO.Conclusion: At this point, no reference plasma concentrations exist for ketamine in ECMO patients, further research may help understand the effects of ECMO on ketamine disposition and that lower ketamine concentrations may be used for effective analgesia or sedation.

Personalized antiseizure medication therapy in critically ill adult patients

Precision medicine has the potential to have a significant impact on both drug development and patient care. It is crucial to not only provide prompt effective antiseizure treatment for critically ill patients after seizures start but also have a proactive mindset and concentrate on epileptogenesis and the underlying cause of the seizures or seizure disorders. Critical illness presents different treatment issues compared with the ambulatory population, which makes it challenging to choose the best antiseizure medications and to administer them at the right time and at the right dose. Since there is a paucity of information available on antiseizure medication dosing in critically ill patients, therapeutic drug monitoring is a useful tool for defining each patient's personal therapeutic range and assisting clinicians in decision-making. Use of pharmacogenomic information relating to pharmacokinetics, hepatic metabolism, and seizure etiology may improve safety and efficacy by individualizing therapy. Studies evaluating the clinical implementation of pharmacogenomic information at the point-of-care and identification of biomarkers are also needed. These studies may make it possible to avoid adverse drug reactions, maximize drug efficacy, reduce drug-drug interactions, and optimize medications for each individual patient. This review will discuss the available literature and provide future insights on precision medicine use with antiseizure therapy in critically ill adult patients.

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.

Polypharmacy, Dosing Trends and Drug-Drug Interaction Patterns Following High-Level Limb Amputation Surgery

OBJECTIVE

To examine peri-operative medication patterns, surrounding major amputation surgeries.

DESIGN

Retrospective chart review of 216 cases of major amputations (transfemoral, hip disarticulation, hemipelvectomy, forequarter) at an academic hospital, examining medications, dosing changes and drug-drug interaction warnings pre- and post-operatively.

RESULTS

Medications increased in 76.9% (166/216), remained the same in 10.6% (23/216), and decreased in 12.5% (27/216) of cases. Average number of medications was 7 pre-operatively and 10 post-operatively. In 189 cases with pre-operative medications present, post-operative dosing remained the same for 74.3%, increased for 9.2%, decreased for 7.6% and was unknown for 8.9% of medications. Increases in each of type C ("monitor therapy"), D ("consider therapy modification) and X ("avoid combination") drug-drug interaction warnings were seen respectively in 59.7%, 62.0% and 5.1% of cases.

CONCLUSION

Polypharmacy is involved pre-operatively and increased post-operatively in most cases of major limb amputation, with agent dosing remaining the same or increased in the majority of cases. Drug-drug interaction warnings also increase. These occur at a time of abrupt changes to the body's size, compartments, and physiologic responses. More research and clinical attention are warranted given anticipated changes in pharmacokinetics and pharmacodynamics.

Availability of information for dosing commonly used medications in special ICU populations

PURPOSE

Medication product labeling was reviewed to determine if sufficient information is available to appropriately calculate dosing regimens for special intensive care unit (ICU) populations, including patients at extremes of body habitus and patients receiving hemodialysis, continuous renal replacement therapy (CRRT), or extracorporeal membrane oxygenation (ECMO).

METHODS

The labeling of the 100 most commonly used injectable medications in the adult ICUs of an academic medical center in Arizona were evaluated. Any information related to adult weight-based dosing, weight descriptors, dosing of patients at extremes of weight (body mass index of <18.5 or >40 kg/m2), and dosing of patients receiving hemodialysis, CRRT, or ECMO was extracted from Food and Drug Administration-approved product labeling. Information was ranked for dosing usefulness on a scale of 0 to 3; an information usefulness score of 2 or greater was considered minimally adequate for dosing special ICU populations.

RESULTS

Among the 100 medications evaluated, the labeling of 47 provided information on weight-based dosing, with the labeling of 30% referring to a specific weight descriptor. The labeling of 15 medications had information on dosing for patients at extremes of body habitus: underweight (3 medications), obesity (12 medications), and extreme obesity (2 medications), with the labeling of 8 medications receiving an information usefulness score of ≥2 (2, 6, and 1 medication in the respective categories). Among the 42 medications whose labeling provided hemodialysis-related dosing information, the labeled information of 52% was assigned a usefulness score of ≥2; among the 3 medications with CRRT-related dosing information, the labeling of 1 received a score of ≥2. ECMO-related dosing information was available for 2 medications, with 1 score of ≥2 assigned.

CONCLUSION

Information in the product labeling of injectable medications commonly used in the ICU is limited and generally inadequate for calculating an appropriate dose for special ICU populations.

Pharmacokinetic Considerations in Amputees

PURPOSE

The purpose of this article is to review the currently available assessment tools for measuring renal function, body weight, and body surface area in the amputee population.

METHODS

PubMed and Web of Science were searched using the following key terms: amputation, dose adjustment, and estimation of body weight. Articles published in languages other than English were excluded from the search.

RESULTS

Despite the increasing prevalence of amputations, there is little literature available that discusses its impact on the patient and how these physiological changes can affect pharmacokinetics. Very little information is available to guide dose adjustment in this patient population. This article discusses several factors to consider when determining optimum dosing regimens in patients with different levels of amputations.

CONCLUSION

This article will evaluate the applicability of methods mentioned in existing literature for measuring changes in renal function, body weight, and body surface area in amputees.

Drug dosing in the critically ill obese patient-a focus on sedation, analgesia, and delirium

Practice guidelines provide clear evidence-based recommendations for the use of drug therapy to manage pain, agitation, and delirium associated with critical illness. Dosing recommendations however are often based on strategies used in patients with normal body habitus. Recommendations specific to critically ill patients with extreme obesity are lacking. Nonetheless, clinicians must craft dosing regimens for this population. This paper is intended to help clinicians design initial dosing regimens for medications commonly used in the management of pain, agitation, and delirium in critically ill patients with extreme obesity. A detailed literature search was conducted with an emphasis on obesity, pharmacokinetics, and dosing. Relevant manuscripts were reviewed and strategies for dosing are provided.

Antithrombotic therapy in patients with acute coronary syndrome complicated by cardiogenic shock or out-of-hospital cardiac arrest: a joint position paper from the European Society of Cardiology (ESC) Working Group on Thrombosis, in association with the Acute Cardiovascular Care Association (ACCA) and European Association of Percutaneous Cardiovascular Interventions (EAPCI)

Timely and effective antithrombotic therapy is critical to improving outcome, including survival, in patients with acute coronary syndrome (ACS). Achieving effective platelet inhibition and anticoagulation, with minimal risk, is particularly important in high-risk ACS patients, especially those with cardiogenic shock (CS) or those successfully resuscitated following out-of-hospital cardiac arrest (OHCA), who have a 30-50% risk of death or a recurrent ischaemic event over the subsequent 30 days. There are unique challenges to achieving effective and safe antithrombotic treatment in this cohort of patients that are not encountered in most other ACS patients. This position paper focuses on patients presenting with CS or immediately post-OHCA, of presumed ischaemic aetiology, and examines issues related to thrombosis and bleeding risk. Both the physical and pharmacological impacts of CS, namely impaired drug absorption, metabolism, altered distribution and/or excretion, associated multiorgan failure, co-morbidities and co-administered treatments such as opiates, targeted temperature management, renal replacement therapy and circulatory or left ventricular assist devices, can have major impact on the effectiveness and safety of antithrombotic drugs. Careful attention to the choice of antithrombotic agent(s), route of administration, drug-drug interactions, therapeutic drug monitoring and factors that affect drug efficacy and safety, may reduce the risk of sub- or supra-therapeutic dosing and associated adverse events. This paper provides expert opinion, based on best available evidence, and consensus statements on optimising antithrombotic therapy in these very high-risk patients, in whom minimising the risk of thrombosis and bleeding is critical to improving outcome.