Population pharmacokinetic analysis of ciprofloxacin in the elderly patients with lower respiratory tract infections

Pharmacokinetics of oral ciprofloxacin in adult patients: A scoping review

AIMS

To map the literature on oral ciprofloxacin's pharmacokinetics and its implications for dose adjustments in specific populations.

METHODS

A scoping review was performed according to the Cochrane Collaboration and JBI and reported following the PRISMA-ScR. Systematic searches on electronic databases were conducted to integrate the current evidence on ciprofloxacin's pharmacokinetics. The quality of the included studies was assessed using ClinPK's checklist.

RESULTS

The search yielded 55 relevant studies. Within the traditional pharmacokinetics studies (n = 46), 86 profiles were examined (72 involving healthy patients and 14 with various clinical conditions). Oral ciprofloxacin's pharmacokinetics were influenced by covariates such as drug interactions (ferrous ions, calcium carbonate, diclofenac and itraconazole), food interactions (calcium-rich foods), elderly populations and renal impairment. Notably, variability in pharmacokinetic parameters existed among subjects, regardless of their health status, underscoring the need for comprehensive population descriptions. Population pharmacokinetic studies (n = 9) identified significant covariates for hospitalized patients, such as creatinine clearance, plasma bicarbonate, estimated glomerular filtration rate, renal replacement therapy, age, sex, total bilirubin, fat-free mass, dietary factors in renal disease, rifampicin for clearance models and body weight for volume of distribution models. Most pharmacokinetic/pharmacodynamic assessments concluded that 1200 mg/day provides a high probability of target attainment for bacteria with minimum inhibitory concentration <0.5 mg L-1 , aiming for an area under the curve for 24 h/minimum inhibitory concentration >125 h.

CONCLUSIONS

This study offers a comprehensive overview regarding oral ciprofloxacin's pharmacokinetics across various health conditions. It highlights the complexities of ciprofloxacin's pharmacokinetics, emphasizing the importance of considering multiple factors in dose adjustments.

Population pharmacokinetics of antibacterial agents in the older population: a literature review

INTRODUCTION

Older individuals face an elevated risk of developing bacterial infections. The optimal use of antibacterial agents in this population is challenging because of age-related physiological alterations, changes in pharmacokinetics (PK) and pharmacodynamics (PD), and the presence of multiple underlying diseases. Therefore, population pharmacokinetics (PPK) studies are of great importance for optimizing individual treatments and prompt identification of potential risk factors.

AREA COVERED

Our search involved keywords such as 'elderly,' 'old people,' and 'geriatric,' combined with 'population pharmacokinetics' and 'antibacterial agents.' This comprehensive search yielded 11 categories encompassing 28 antibacterial drugs, including vancomycin, ceftriaxone, meropenem, and linezolid. Out of 127 studies identified, 26 (20.5%) were associated with vancomycin, 14 (11%) with meropenem, and 14 (11%) with piperacillin. Other antibacterial agents were administered less frequently.

EXPERT OPINION

PPK studies are invaluable for elucidating the characteristics and relevant factors affecting the PK of antibacterial agents in the older population. Further research is warranted to develop and validate PPK models for antibacterial agents in this vulnerable population.

Key Factors in Effective Patient-Tailored Dosing of Fluoroquinolones in Urological Infections: Interindividual Pharmacokinetic and Pharmacodynamic Variability

Fluoroquinolones (FQs) are a critical group of antimicrobials prescribed in urological infections as they have a broad antimicrobial spectrum of activity and a favorable tissue penetration at the site of infection. However, their clinical practice is not problem-free of treatment failure, risk of emergence of resistance, and rare but important adverse effects. Due to their critical role in clinical improvement, understanding the dose-response relation is necessary to optimize the effectiveness of FQs therapy, as it is essential to select the right antibiotic at the right dose for the right duration in urological infections. The aim of this study was to review the published literature about inter-individual variability in pharmacological processes that can be responsible for the clinical response after empiric dose for the most commonly prescribed urological FQs: ciprofloxacin, levofloxacin, and moxifloxacin. Interindividual pharmacokinetic (PK) variability, particularly in elimination, may contribute to treatment failure. Clearance related to creatinine clearance should be specifically considered for ciprofloxacin and levofloxacin. Likewise, today, undesired interregional variability in FQs antimicrobial activity against certain microorganisms exists. FQs pharmacology, patient-specific characteristics, and the identity of the local infecting organism are key factors in determining clinical outcomes in FQs use.

Allele-specific collateral and fitness effects determine the dynamics of fluoroquinolone resistance evolution

A promising strategy to overcome the evolution of antibiotic-resistant bacteria is to use collateral sensitivity-informed antibiotic treatments that rely on cycling or mixing of antibiotics, such that that resistance toward one antibiotic confers increased sensitivity to the other. Here, focusing on multistep fluoroquinolone resistance in Streptococcus pneumoniae, we show that antibiotic resistance induces diverse collateral responses whose magnitude and direction are determined by allelic identity. Using mathematical simulations, we show that these effects can be exploited via combination treatment regimens to suppress the de novo emergence of resistance during treatment.

Collateral sensitivity (CS), which arises when resistance to one antibiotic increases sensitivity toward other antibiotics, offers treatment opportunities to constrain or reverse the evolution of antibiotic resistance. The applicability of CS-informed treatments remains uncertain, in part because we lack an understanding of the generality of CS effects for different resistance mutations, singly or in combination. Here, we address this issue in the gram-positive pathogen Streptococcus pneumoniae by measuring collateral and fitness effects of clinically relevant gyrA and parC alleles and their combinations that confer resistance to fluoroquinolones. We integrated these results in a mathematical model that allowed us to evaluate how different in silico combination treatments impact the dynamics of resistance evolution. We identified common and conserved CS effects of different gyrA and parC alleles; however, the spectrum of collateral effects was unique for each allele or allelic pair. This indicated that allelic identity can impact the evolutionary dynamics of resistance evolution during monotreatment and combination treatment. Our model simulations, which included the experimentally derived antibiotic susceptibilities and fitness effects, and antibiotic-specific pharmacodynamics revealed that both collateral and fitness effects impact the population dynamics of resistance evolution. Overall, we provide evidence that allelic identity and interactions can have a pronounced impact on collateral effects to different antibiotics and suggest that these need to be considered in models examining CS-based therapies.

Pharmacokinetic/pharmacodynamic target attainment of ciprofloxacin in adult patients on general wards with adequate and impaired renal function

Limited prospective data on pharmacokinetic/pharmacodynamic (PK/PD) target attainment of ciprofloxacin in patients with adequate and impaired renal function (eGFR <30 mL/min/1.73m²) are available in the literature. We aimed to investigate whether the PK/PD target (AUC/MIC ≥125) is attained in patients with adequate and impaired renal function receiving regular and reduced ciprofloxacin doses. This prospective observational cohort study included adult patients on general wards treated with ciprofloxacin. Three blood samples per patient were obtained for ciprofloxacin concentration measurement. Individual AUCs were calculated using a population PK model developed by non-linear mixed-effects modelling. Forty patients were included, of whom eight had impaired renal function and were treated with a guideline-recommended reduced dose. Using the clinical breakpoint MIC of the most isolated bacteria (Escherichia coli, 0.25 mg/L), AUC_0-24/MIC ≥125 was attained in 13/32 (41%) patients with adequate renal function receiving regular doses and in 1/8 (13%) patients with impaired renal function receiving reduced doses. Median drug exposure (AUC_0-24) for patients with impaired renal function was 19.0 [interquartile range (IQR) 14.2-23.3] mg/L•h, which was statistically significantly lower than that for patients with adequate renal function [29.3 (IQR 25.0-36.0) mg/L•h] (P < 0.01). AUC_0-24/MIC ≥125 is not attained in the majority of adult patients on general wards for clinically relevant bacteria with MICs at or just below the clinical breakpoint. The risk of not attaining the target appears to be highest in patients with impaired renal function receiving guideline-recommended reduced doses, as drug exposure is significantly lower in these patients.

Considerations for the optimal management of antibiotic therapy in elderly patients

OBJECTIVES

To maximise efficacy and minimise toxicity, special considerations are required for antibiotic prescription in elderly patients. This review aims to provide practical suggestions for the optimal management of antibiotic therapy in elderly patients.

METHODS

This was a narrative review. A literature search of published articles in the last 15 years on antibiotics and elderly patients was performed using the Cochrane Library and PubMed electronic databases. The three priority areas were identified: (i) pharmacokinetics/pharmacodynamics (PK/PD) for optimising dosage regimens and route of administration; (ii) antibiotic dosages in some special subpopulations; and (iii) treatment considerations relating to different antibiotic classes and their adverse events.

RESULTS

Clinicians should understand the altered PK/PD of drugs in this population owing to co-morbid conditions and normal physiological changes associated with ageing. The body of evidence justifies the need for individualised dose selection, especially in patients with impaired renal and liver function. Clinicians should be aware of the major drug-drug interactions commonly observed in the elderly as well as potential side effects.

CONCLUSION

Antibiotic therapy in the elderly requires a comprehensive approach, including strategies to improve appropriate antibiotic prescribing, limit their use for uncomplicated infections and ensure the attainment of an optimal PK/PD target. To this purpose, further studies involving the elderly are needed to better understand the PK of antibiotics. Moreover, it is necessary to assess the role therapeutic drug monitoring in guiding antibiotic therapy in elderly patients in order to evaluate its impact on clinical outcome.

A Physiologically-Based Pharmacokinetic Model to Describe Ciprofloxacin Pharmacokinetics Over the Entire Span of Life

Background

Physiologically-based pharmacokinetic (PBPK) modeling has received growing interest as a useful tool for the assessment of drug pharmacokinetics by continuous knowledge integration.

Objective

The objective of this study was to build a ciprofloxacin PBPK model for intravenous and oral dosing based on a comprehensive literature review, and evaluate the predictive performance towards pediatric and geriatric patients.

Methods

The aim of this report was to establish confidence in simulations of the ciprofloxacin PBPK model along the development process to facilitate reliable predictions outside of the tested adult age range towards the extremes of ages. Therefore, mean data of 69 published clinical trials were identified and integrated into the model building, simulation and verification process. The predictive performance on both ends of the age scale was assessed using individual data of 258 subjects observed in own clinical trials.

Results

Ciprofloxacin model verification demonstrated no concentration-related bias and accurate simulations for the adult age range, with only 4.8% of the mean observed data points for intravenous administration and 12.1% for oral administration being outside the simulated twofold range. Predictions towards the extremes of ages for the area under the plasma concentration–time curve (AUC) and the maximum plasma concentration (C_max) over the entire span of life revealed a reliable estimation, with only two pediatric AUC observations outside the 90% prediction interval.

Conclusion

Overall, this ciprofloxacin PBPK modeling approach demonstrated the predictive power of a thoroughly informed middle-out approach towards age groups of interest to potentially support the decision-making process.

Electronic supplementary material

The online version of this article (10.1007/s40262-018-0661-6) contains supplementary material, which is available to authorized users.

Pharmacotherapy for community-acquired pneumonia in the elderly

INTRODUCTION

Community-acquired pneumonia (CAP) is an increasing problem in the elderly that is associated with elevated morbidity and mortality. Given the expected increased life expectancy, this problem is only likely to worsen, so it has been considered that treatment effects must be examined separately in elderly adults with CAP. Areas covered: In this narrative review, we give an update of the available data of antibiotics for elderly patients with CAP. Clinical features, drug pharmacokinetics and pharmacodynamics, adverse effects, and outcomes differ in CAP depending on patient age. Older age, for example, can affect the effect of specific antibiotic regimens on important CAP clinical outcomes. Current guidelines do not offer specific recommendations for the management of CAP in elderly patients. Expert opinion: Most of our knowledge about the treatment of CAP in elderly patients has been gained from studies in young populations. However, elderly patients with CAP deserve special attention because there are several factors in this population that could influence their response to antibiotic regimens in CAP.

Management of Inflammatory Bowel Disease in the Elderly

OPINION STATEMENT

A substantial and growing proportion of patients with inflammatory bowel disease (IBD) are elderly, and these patients require tailored treatment strategies. However, significant challenges exist in the management of this population due to the paucity of data. Establishing the initial diagnosis and assessing the etiology of future symptoms and flares can be challenging as several other prevalent diseases can masquerade as IBD, such as ischemic colitis, diverticular disease, and infectious colitis. Important pharmacologic considerations include reduced glomerular filtration rate and drug-drug interactions in the elderly. No drug therapy is absolutely contraindicated in this population; however, special risk and benefit assessments should be made. Older patients are more susceptible to side effects of steroids such as delirium, fractures, and cataracts. Budesonide can be an appropriate alternative for mild to moderate ulcerative colitis (UC) or Crohn's disease (CD) as it has limited systemic absorption. Pill size and quantity, nephrotoxicity, and difficulty of administration of rectal preparations should be considered with 5-aminosalicylic (5-ASA) therapy. Biologics are very effective, but modestly increase the risk of infection in a susceptible group. Based on their mechanisms, integrin receptor antagonists (e.g., vedolizumab) may reduce these risks. Use of antibiotics for anorectal or fistulizing CD or pouchitis in UC increases the risk of Clostridium difficile infection. Pre-existing comorbidities, functional status, and nutrition are important indicators of surgical outcomes. Morbidity and mortality are increased among IBD patients undergoing surgery, often due to postoperative complications or sepsis. Elderly adults with IBD, particularly UC, have very high rates of venous thromboembolism (VTE). Colonoscopy appears safe, but the optimal surveillance interval has not been well defined. Should the octogenarian, nonagenarian, and centurion undergo colonoscopy? The length of surveillance should likely account for the individual's overall life expectancy. Specific health maintenance should emphasize administering non-live vaccines to patients on thiopurines or biologics and regular skin exams for those on thiopurines. Smoking cessation is crucial to overall health and response to medical therapy, even among UC patients. This article will review management of IBD in the elderly.