Continuous infusion meropenem and ticarcillin-clavulanate in pediatric cystic fibrosis patients

A Review of Extended and Continuous Infusion Beta-Lactams in Pediatric Patients

Intravenous beta-lactam antibiotics are the most prescribed antibiotic class in US hospitalized patients of all ages; therefore, optimizing their dosing is crucial. Bactericidal killing is best predicted by the time in which beta-lactam drug concentrations are maintained above the organism's minimum inhibitory concentration (MIC), rather than achievement of a high peak concentration. As such, administration of beta-lactam antibiotics via extended or continuous infusions over a minimum of 3 hours, rather than standard infusions over approximately 30 minutes, has been associated with improved achievement of pharmacodynamic targets and improved clinical outcomes in adult medical literature. This review summarizes the pediatric medical literature. Applicable studies include pharmacodynamic models, case series, retrospective analyses, and prospective studies on the use of extended infusion and continuous infusion penicillins, cephalosporins, carbapenems, and monobactams in neonates, infants, children, and adolescents. Specialized patient populations with unique pharmacokinetics and high-risk infections (neonates, critically ill, febrile neutropenia, cystic fibrosis) are also reviewed. While more studies are needed to confirm prospective clinical outcomes, the current body of evidence suggests extended and continuous infusions of beta-lactam antibiotics are well tolerated in children and improve achievement of pharmacokineticpharmacodynamic targets with similar or superior clinical outcomes, particularly in infections associated with high MICs.

Extended or Continuous Infusion of Carbapenems in Children with Severe Infections: A Systematic Review and Narrative Synthesis

We systematically reviewed the efficacy and safety of an extended or continuous infusion (EI/CI) versus short-term infusion (STI) of carbapenems in children with severe infections. Databases, including PubMed, Embase, the Cochrane Library, Clinicaltrials.gov, China National Knowledge Infrastructure, WanFang Data, and SinoMed, were systematically searched from their inceptions to 10 August 2020, for all types of studies (such as randomized controlled trials (RCTs), retrospective studies, and pharmacokinetic or population pharmacokinetic (PK/PPK) studies) comparing EI/CI versus STI in children with severe infection. There was no limitation on language, and a manual search was also conducted. The data were screened, evaluated, extracted, and reviewed by two researchers independently. Quantitative (meta-analysis) or qualitative analyses of the included studies were performed. Twenty studies (including two RCTs, one case series, six case reports, and 11 PK/PPK studies) were included in this review (CRD42020162845). The RCTs’ quality evaluation results revealed a risk of selection and concealment bias. Qualitative analysis of RCTs demonstrated that, compared with STI, an EI (3 to 4 h) of meropenem in late-onset neonatal sepsis could improve the clinical effectiveness and microbial clearance rates, and reduce the rates of mortality; however, the differences in the incidence of other adverse events were not statistically significant. Retrospective studies showed that children undergoing an EI of meropenem experienced satisfactory clinical improvement. In addition, the results of the PK/PPK study showed that an EI (3 or 4 h)/CI of carbapenems in severely infected children was associated with a more satisfactory goal achievement rate (probability of target attainment) and a cumulative fraction of response than STI therapy. In summary, the EI/CI of carbapenems in children with severe infection has a relatively sufficient PK or pharmacodynamic (PD) basis and satisfactory efficacy and safety. However, due to the limited quantity and quality of studies, the EI/CI therapy should not be used routinely in severely infected children. This conclusion should be further verified by more high-quality controlled clinical trials or observational studies based on PK/PD theories.

Stability of Meropenem After Reconstitution for Administration by Prolonged Infusion

Objective: Meropenem is a parenteral carbapenem antibiotic which has a broad spectrum of activity against aerobes and anaerobes. Meropenem's bactericidal activity is determined by the time during which meropenem concentration remains above the minimal inhibition concentration (MIC) during the dosing interval. Thus, prolonged infusion is the optimal way to maximize the time-dependant activity. However, studies to date have shown that carbapenems and in particular, meropenem, are relatively unstable in solution. The aims of this study were therefore (1) to establish the effects of temperature on the concentration of a generic brand reconstituted meropenem solution and (2) to determine whether 24-hour continuous infusion is possible without concentrations dropping below the recommended 90%. Method: Preliminary examination was carried out by the means of nuclear magnetic resonance (NMR) spectroscopy. Meropenem was subsequently assayed using high-performance liquid chromatography (HPLC). The method was developed and validated in compliance with International Council for Harmonisation (ICH) guidelines. Meropenem's stability was examined at two temperatures 22°C and 33°C to mimic average and high temperature in hospital wards. Solutions were prepared aseptically at the clinically relevant concentration. Results: NMR results obtained showed an increase in open ring methyl groups peak intensity, indicating that meropenem begins to degrade upon dissolution (d=1.05 and 1.25). Results obtained from quantitative HPLC confirm that meropenem concentrations dropped to 90% of initial concentration at 7.4 hours and 5.7 hours at 22°C and 33°C, respectively. Conclusion: Although results obtained indicate that meropenem should not be continuously infused over 24 hours, it is possible that meropenem could be continuously infused for at least 7 hours if temperature does not exceed 22°C and for 5 hours if temperature does not exceed 33°C.

Clinical Outcomes With Continuous Nafcillin Infusions in Children

OBJECTIVES

The primary objective of this study was to describe the clinical outcomes of continuous nafcillin infusion in pediatric patients.

METHODS

This was a retrospective case study performed at a freestanding, tertiary care children's hospital. Subjects were included if they were at least 30 days old and had received more than 1 dose of nafcillin by continuous infusion (CI) between January 1, 2009, and December 31, 2012. Clinical and microbiological data were extracted from the medical record. Documented adverse events potentially associated with nafcillin were recorded. Treatment success was defined by any one of the following outcomes without the presence of conflicting data: microbiological cure, prescriber-documented treatment success, or normalization of abnormal clinical or laboratory parameters.

RESULTS

Forty subjects with a median of 9 (interquartile range [IQR], 2.3-12) years of age were included. Median length of stay (in days) for all indications observed was 7 (IQR, 5-21.8) days. Extended lengths of stay, indicated by ≥10 days, were more common in cases of endocarditis, skin and soft tissue infection, and bacteremia. Adverse reactions were documented in 20% of patients.

CONCLUSIONS

In this pediatric study, overall treatment success was observed in 92.5% of patients. Microbiological cure was documented in 91.3% of patients by using follow-up cultures. Length of stay may be positively impacted by CI nafcillin. Continuously infused nafcillin appears to be an acceptable alternative to intermittently infused nafcillin in children. Further studies are needed to address the question of whether clinical outcomes of CI nafcillin are superior to those of conventional infusion.

Population pharmacokinetics of meropenem administered as a prolonged infusion in children with cystic fibrosis

OBJECTIVES

Meropenem is frequently used to treat pulmonary exacerbations in children with cystic fibrosis (CF) in the USA. Prolonged-infusion meropenem improves the time that free drug concentrations remain above the MIC (fT> MIC) in adults, but data in CF children are sparse. We describe the population pharmacokinetics, tolerability and treatment burden of prolonged-infusion meropenem in CF children.

METHODS

Thirty children aged 6-17 years with a pulmonary exacerbation received 40 mg/kg meropenem every 8 h; each dose was administered as a 3 h infusion. Pharmacokinetics were determined using population methods in Pmetrics. Monte Carlo simulation was employed to compare 0.5 with 3 h infusions to estimate the probability of pharmacodynamic target attainment (PTA) at 40% fT> MIC. NCT#01429259.

RESULTS

A two-compartment model fitted the data best with clearance and volume predicted by body weight. Clearance and volume of the central compartment were 0.41 ± 0.23 L/h/kg and 0.30 ± 0.17 L/kg, respectively. Half-life was 1.11 ± 0.38 h. At MICs of 1, 2 and 4 mg/L, PTAs for the 0.5 h infusion were 87.6%, 70.1% and 35.4%, respectively. The prolonged infusion increased PTAs to >99% for these MICs and achieved 82.8% at 8 mg/L. Of the 30 children, 18 (60%) completed treatment with prolonged infusion; 5 did so at home without any reported burden. Nine patients were changed to a 0.5 h infusion when discharged home.

CONCLUSIONS

In these CF children, meropenem clearance was greater compared with published values from non-CF children. Prolonged infusion provided an exposure benefit against pathogens with MICs ≥1 mg/L, was well tolerated and was feasible to administer in the hospital and home settings, the latter depending on perception and family schedule.

Pharmacokinetics and pharmacodynamics of continuous-infusion meropenem in pediatric hematopoietic stem cell transplant patients

This study explored the pharmacokinetics and the pharmacodynamics of continuous-infusion meropenem in a population of pediatric hematopoietic stem cell transplant (HSCT) patients who underwent therapeutic drug monitoring. The relationship between meropenem clearance (CLM) and estimated creatinine clearance (CLCR) was assessed by nonlinear regression. A Monte Carlo simulation was performed to investigate the predictive performance of five dosing regimens (15 to 90 mg/kg of body weight/day) for the empirical treatment of severe Gram-negative-related infections in relation to four different categories of renal function. The optimal target was defined as a probability of target attainment (PTA) of ≥90% at steady-state concentration-to-MIC ratios (C SS/MIC) of ≥1 and ≥4 for MICs of up to 8 mg/liter. A total of 21 patients with 44 meropenem C SS were included. A good relationship between CLM and estimated CLCR was observed (r (2) = 0.733). Simulations showed that at an MIC of 2 mg/liter, the administration of continuous-infusion meropenem at doses of 15, 30, 45, and 60 mg/kg/day may achieve a PTA of ≥90% at a C SS/MIC ratio of ≥4 in the CLCR categories of 40 to <80, 80 to <120, 120 to <200, and 200 to <300 ml/min/1.73 m(2), respectively. At an MIC of 8 mg/liter, doses of up to 90 mg/kg/day by continuous infusion may achieve optimal PTA only in the CLCR categories of 40 to <80 and 80 to <120 ml/min/1.73 m(2). Continuous-infusion meropenem at dosages up to 90 mg/kg/day might be effective for optimal treatment of severe Gram-negative-related infections in pediatric HSCT patients, even when caused by carbapenem-resistant pathogens with an MIC of up to 8 mg/liter.