Cefepime and Ceftazidime Safety in Hospitalized Infants

Ceftazidime-related neurotoxicity in a patient with renal impairment: a case report and literature review

PURPOSE

We present the case of a 67-year-old woman with severely reduced renal clearance suffering from ceftazidime-induced encephalopathy. Subsequently, we search the literature to review and describe the neurotoxicity of ceftazidime.

METHODS

A search string was developed to search PubMed for relevant cases from which relevant information was extracted. Using the collected data a ROC analysis was performed in R to determine a neurotoxicity threshold.

RESULTS

Our patient suffered from progressive loss of consciousness and myoclonic seizures, with improvements noted a few days after discontinuation of treatment. The dose was not appropriately reduced to take into account her reduced renal function. The highest ceftazidime concentration recorded was 234.9 mg/mL. Using the Naranjo score we found a probable relationship between our patient's encephalopathy and ceftazidime administration. In the literature we found a total of 32 similar cases, most of which also had some form of renal impairment. Using our collected data and ceftazidime concentrations provided in the literature, a ROC analysis provided a neurotoxicity threshold of 78 mg/L for ceftazidime neurotoxicity.

CONCLUSION

Ceftazidime-related neurotoxicity is a known issue, especially in patients with severe renal impairment. Yet no concrete toxicity threshold has been reported so far. We propose the first toxicity threshold for ceftazidime of 78 mg/L. Future prospective studies are needed to validate and optimize the neurotoxicity threshold as upper limit for ceftazidime therapeutic drug monitoring.

Comparison of Outcomes in Neonates Receiving Cefepime or Ceftazidime

OBJECTIVES

Cefepime and ceftazidime are alternatives to cefotaxime for management of Gram-negative infections in neonates. The objective was to evaluate neonatal outcomes when receiving cefepime or ceftazidime.

METHODS

This was a single center, retrospective analysis of neonates exposed to at least 24 hours of cefepime or ceftazidime between June 1, 2018, and June 1, 2021. The primary outcome was incidence of culture-positive, late-onset sepsis after initial exposure. Secondary outcomes included culture-negative, respiratory, urinary tract, and resistant infections; necrotizing enterocolitis; length of stay; age at discharge; mortality; and adverse effects.

RESULTS

A total of 105 neonates were included (cefepime, n = 50; ceftazidime, n = 55). Baseline characteristics were similar except more cumulative days of antibiotics (25.0 [IQR, 9.3-47.0] versus 9.0 [IQR, 4.0-23.5], p = 0.01), central line days (11.0 [IQR, 6.0-40.0] versus 6.5 [IQR, 0.0-11.5], p = 0.001), and ventilator days (13.0 [IQR, 2.3-48.0] versus 4.0 [IQR, 0.0-25.0], p = 0.02) were found in the cefepime group than in the ceftazidime group. There was no difference in culture-positive sepsis after the initial antibiotic course (8.0% versus 3.6%, p = 0.42). Statistical differences were seen in select secondary outcomes including treated respiratory infections (16.0% versus 1.8%, p = 0.01), length of stay greater than 30 days (72.0% versus 50.9%, p = 0.03), and mortality (26.0% versus 9.1%, p = 0.02). These differences were not observed in analyses adjusted for ventilator days.

CONCLUSIONS

This analysis found no difference in culture-positive sepsis in neonates exposed to cefepime versus ceftazidime. Moreover, there were no differences in secondary outcomes in adjusted analyses. Further research is needed to assess neonatal outcomes in a larger analysis.

Population Pharmacokinetics and Dosing Optimization of Ceftazidime in Term Asphyxiated Neonates during Controlled Therapeutic Hypothermia

Ceftazidime is an antibiotic commonly used to treat bacterial infections in term neonates undergoing controlled therapeutic hypothermia (TH) for hypoxic-ischemic encephalopathy after perinatal asphyxia. We aimed to describe the population pharmacokinetics (PK) of ceftazidime in asphyxiated neonates during hypothermia, rewarming, and normothermia and propose a population-based rational dosing regimen with optimal PK/pharmacodynamic (PD) target attainment. Data were collected in the PharmaCool prospective observational multicenter study. A population PK model was constructed, and the probability of target attainment (PTA) was assessed during all phases of controlled TH using targets of 100% of the time that the concentration in the blood exceeds the MIC (T>MIC) (for efficacy purposes and 100% T>4×MIC and 100% T>5×MIC to prevent resistance). A total of 35 patients with 338 ceftazidime concentrations were included. An allometrically scaled one-compartment model with postnatal age and body temperature as covariates on clearance was constructed. For a typical patient receiving the current dose of 100 mg/kg of body weight/day in 2 doses and assuming a worst-case MIC of 8 mg/L for Pseudomonas aeruginosa, the PTA was 99.7% for 100% T>MIC during hypothermia (33.7°C; postnatal age [PNA] of 2 days). The PTA decreased to 87.7% for 100% T>MIC during normothermia (36.7°C; PNA of 5 days). Therefore, a dosing regimen of 100 mg/kg/day in 2 doses during hypothermia and rewarming and 150 mg/kg/day in 3 doses during the following normothermic phase is advised. Higher-dosing regimens (150 mg/kg/day in 3 doses during hypothermia and 200 mg/kg/day in 4 doses during normothermia) could be considered when achievements of 100% T>4×MIC and 100% T>5×MIC are desired.

Treatment options for neonatal infections in the post-cefotaxime era

INTRODUCTION

: Cefotaxime has been used for the management of neonatal infections since the 1990s for suspected meningitis and to mitigate gentamicin-associated renal injury. Its shortage in 2015 and subsequent removal from the U.S. pharmaceutical market forced providers to consider alternatives. Ceftriaxone, a cephalosporin with an identical antibacterial spectrum of activity to cefotaxime, is contraindicated in neonates due to its risk of biliary pseudolithiasis. Ceftazidime was recommended as an alternative by the American Academy of Pediatrics but is inequivalent.

AREAS COVERED

: This article addresses indications for cephalosporin use and considerations when selecting an alternative to cefotaxime. Differences among cefotaxime, ceftriaxone, ceftazidime, and cefepime are discussed and compared to the standard-of-care presumptive regimen, ampicillin and gentamicin. The authors consider the data behind the neonatal contraindication to ceftriaxone and provide recommendations for their application to practice.

EXPERT OPINION

: The data against ceftriaxone use in neonates remain poor, particularly in the context of the cefotaxime shortage and lack of an equivalent alternative. Ceftriaxone could be considered in low-risk neonates without hyperbilirubinemia or exposure to calcium-containing fluids on a case-by-case basis. Ceftazidime monotherapy for presumptive management of neonatal infections is inappropriate; cefepime should be more frequently utilized in neonates who are poor candidates for ceftriaxone.

Potential Antibiotics for the Treatment of Neonatal Sepsis Caused by Multidrug-Resistant Bacteria

Neonatal sepsis causes up to an estimated 680,000 deaths annually worldwide, predominantly in low- and middle-income countries (LMICs). A significant and growing proportion of bacteria causing neonatal sepsis are resistant to multiple antibiotics, including the World Health Organization-recommended empiric neonatal sepsis regimen of ampicillin/gentamicin. The Global Antibiotic Research and Development Partnership is aiming to develop alternative empiric antibiotic regimens that fulfil several criteria: (1) affordable in LMIC settings; (2) activity against neonatal bacterial pathogens, including extended-spectrum β-lactamase producers, gentamicin-resistant Gram-negative bacteria, and methicillin-resistant Staphylococcus aureus (MRSA); (3) a licence for neonatal use or extensive experience of use in neonates; and (4) minimal toxicities. In this review, we identify five antibiotics that fulfil these criteria: amikacin, tobramycin, fosfomycin, flomoxef, and cefepime. We describe the available characteristics of each in terms of mechanism of action, resistance mechanisms, clinical pharmacokinetics, pharmacodynamics, and toxicity profile. We also identify some knowledge gaps: (1) the neonatal pharmacokinetics of cefepime is reliant on relatively small and limited datasets, and the pharmacokinetics of flomoxef are also reliant on data from a limited demographic range and (2) for all reviewed agents, the pharmacodynamic index and target has not been definitively established for both bactericidal effect and emergence of resistance, with many assumed to have an identical index/target to similar class molecules. These five agents have the potential to be used in novel combination empiric regimens for neonatal sepsis. However, the data gaps need addressing by pharmacokinetic trials and pharmacodynamic characterisation.

Cefepime Dosing in Neonates: What is the Evidence?

OBJECTIVE

Recommended cefepime dosing strategies in neonates varies in commonly utilized dosing references with regard to dose and frequency. The objective of this review is to summarize and evaluate the available literature describing cefepime dosing in neonatal patients.

STUDY DESIGN

We performed a literature review in MEDLINE using the keyword cefepime. The search was limited to the English language, humans, and patients <2 months of age. We evaluated four pharmacokinetic studies and two studies describing the use of cefepime in clinical practice.

RESULTS

The available studies assessing cefepime serum concentrations in neonatal patients demonstrated maintenance of adequate pharmacokinetic parameters when utilizing a dosing frequency of every 12 hours, specifically for organisms with a minimum inhibitory concentration (MIC) ≤ 8 mg/L. In studies evaluating clinical outcomes of cefepime use in neonates, the most frequent adverse effects reported included seizures and hypophosphatemia. Microbiologic cure was demonstrated with a dosing regimen of 50 mg/kg per dose every 12 hours.

CONCLUSION

Cefepime dosed 30 to 50 mg/kg per dose every 12 hours may be appropriate to achieve a concentration two to four times above an MIC ≤ 8 mg/L for at least 60% of the dosing interval in neonatal patients.

Population Pharmacokinetics and Dosing Optimization of Ceftazidime in Infants

Ceftazidime, a third-generation cephalosporin, can be used for the treatment of adults and children with infections due to susceptible bacteria. To date, the pediatric pharmacokinetic data are limited in infants, and therefore we aimed to evaluate the population pharmacokinetics of ceftazidime in infants and to define the appropriate dose to optimize ceftazidime treatment. Blood samples were collected from children treated with ceftazidime, and concentrations of the drug were quantified by high-performance liquid chromatography with UV detection (HPLC-UV). A population pharmacokinetic analysis was performed using NONMEM software (version 7.2.0). Fifty-one infants (age range, 0.1 to 2.0 years) were included. Sparse pharmacokinetic samples (n = 90) were available for analysis. A one-compartment model with first-order elimination showed the best fit with the data. A covariate analysis identified that body weight and creatinine clearance (CL_CR) were significant covariates influencing ceftazidime clearance. Monte Carlo simulation demonstrated that the currently used dosing regimen of 50 mg/kg twice daily was associated with a high risk of underdosing in infants. In order to reach the target of 70% of the time that the free antimicrobial drug concentration exceeds the MIC (fT_>MIC), 25 mg/kg every 8 h (q8h) and 50 mg/kg q8h were required for MICs of 4 and 8 mg/liter, respectively. The population pharmacokinetic characteristics of ceftazidime were evaluated in infants. An evidence-based dosing regimen was established based on simulation.