Fluconazole is being increasingly used to prevent and treat invasive candidiasis in neonates, yet dosing is largely empirical due to the lack of adequate pharmacokinetic (PK) data. We performed a multicenter population PK study of fluconazole in 23-to 40-week-gestation infants less than 120 days of age. We developed a population PK model using nonlinear mixed effect modeling (NONMEM) with the NONMEM algorithm. Covariate effects were predefined and evaluated based on estimation precision and clinical significance. We studied fluconazole PK in 55 infants who at enrollment had a median (

Improvements in neonatal intensive care during the last 20 years have increased the survival of the most immature newborns at 23 weeks from 0% to 65% at some centres, although rates vary widely among neonatal care centres. University of Utah, USA data show that each week in utero after week 23 raises survival by 6-9%, to 90% by 27-28 weeks and 95% by 33 weeks. Provision of care in specialised centres to provide high-risk obstetric and neonatal intensive care, prenatal treatment with corticosteroids, postnatal treatment with surfactant and nitric oxide, and improvements in respirators and equipment to care for extremely immature infants all contribute to these changes. The increased rate of survival for extremely premature newborns has not been accompanied by an increased rate of severe intraventricular haemorrhage or neurological impairment, such as cerebral palsy. Regardless, intraventricular haemorrhage remains a significant problem, especially if associated with post-haemorrhagic hydrocephalus, leading to long-term neurological impairment and decreased survival. Necrotising enterocolitis (NEC) is more common in premature than in term newborns and is the most frequent cause of short bowel syndrome in infancy. Survival after surgery for NEC has improved during the last two decades, but complications of nutritional support produce many long-term problems. Retinopathy of prematurity (ROP) remains a frequent cause of neurosensory impairment for extremely premature newborns. Laser photocoagulation for advanced ROP is more effective than cryotherapy for preventing retinal detachment and improving visual outcomes. Despite prenatal corticosteroid treatment and postnatal surfactant administration, many extremely premature newborns still develop bronchopulmonary dysplasia. Abnormal pulmonary function may persist into adulthood, but newer ventilators and management schemes appear to be reducing this long-term morbidity. Many changes in neonatal care occur each year, but carefully controlled outcome studies are needed to evaluate the effectiveness of these newer styles of neonatal intensive care.

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Background Suspected or complicated intra-abdominal infections are common in young infants and lead to significant morbidity and mortality. Meropenem is a broad-spectrum antimicrobial agent with excellent activity against pathogens associated with intra-abdominal infections in this population. The purpose of this study was to determine the pharmacokinetics (PK) of meropenem in young infants as a basis for optimizing dosing and minimizing adverse events. Methods Premature and term infants <91 days of age hospitalized in 24 neonatal intensive care units were studied. Limited PK sampling was performed following single and multiple doses of meropenem 20–30 mg/kg of body weight every 8–12 hours based on postnatal and gestational age at birth. Population and individual patient (Bayesian) PK parameters were estimated using NONMEM®. Results Two hundred infants were enrolled and received study drug. One hundred eighty-eight infants with 780 plasma meropenem concentrations were analyzed. Their median (range) gestational age at birth and postnatal age at PK evaluation were 28 (23–40) weeks and 21 (1–92) days, respectively. In the final PK model, meropenem clearance (CL) was strongly associated with serum creatinine (SCR) and postmenstrual age (PMA) (CL [L/h/kg] = 0.12*[(0.5/SCR)**0.27]*[(PMA/32.7)**1.46]). Meropenem concentrations remained >4 μg/mL for 50% of the dose interval and >2 μg/mL for 75% of the dose interval in 96% and 92% of patients, respectively. The estimated penetration of meropenem into the cerebrospinal fluid was 70% (5–148). Conclusions Meropenem dosing strategies based on postnatal and gestational age achieved therapeutic drug exposure in almost all infants.