Cefepime pharmacokinetics in critically ill children and young adults undergoing continuous kidney replacement therapy.

OBJECTIVES: Cefepime is an antibiotic commonly used to treat sepsis and is cleared by renal excretion. Cefepime dosing requires adjustment in patients with decreased kidney function and in those receiving continuous kidney replacement therapy (CKRT). We aimed to characterize cefepime PK in a diverse cohort of critically ill paediatric patients on CKRT. METHODS: Patients were identified from an ongoing pharmacokinetic/pharmacodynamic (PK/PD) study of beta-lactam antibiotics, and were included if they had received at least two cefepime doses in the ICU and were on CKRT for at least 24 h. PK parameters were estimated using MwPharm++ with Bayesian estimation and a paediatric population PK model. Target attainment was assessed as time of free cefepime concentrations above minimum inhibitory concentration (fT > 1× or 4 × MIC). RESULTS: Seven patients were included in the study (ages 2 to 20 years). CKRT indications included liver failure (n = 1), renal failure (n = 4) and fluid overload (n = 2). Total effluent flow rates ranged from 1833 to 3115 (mean 2603) mL/1.73 m2/h, while clearance was 2.11-3.70 (mean 3.0) L/h/70 kg. Effluent flows were lower, but clearance and fT > MIC were similar to paediatric data published previously. Using Pseudomonas aeruginosa MIC breakpoints, all patients had 100% of dosing interval above MIC, but only one had 100% of dosing interval above 4× MIC. CONCLUSIONS: Since most patients failed to attain stringent targets of 100% fT > 4×  MIC, model-informed precision dosing may benefit such patients.

Pharmacokinetics of meropenem in children receiving continuous renal replacement therapy: Validation of clinical trial simulations.

Meropenem is frequently prescribed in critically ill children receiving continuous renal replacement therapy (CRRT). We previously used clinical trial simulations to evaluate dosing regimens of meropenem in this population and reported that a dose of 20 mg/kg every 12 hours optimizes target attainment. Meropenem pharmacokinetics were investigated in this prospective, open-label study to validate our previous in silico predictions. Seven patients received meropenem (13.8-22 mg/kg) administered intravenously every 12 hours as part of standard care. A mean dose of 18.6 mg/kg of meropenem was administered, resulting in a mean peak concentration of 80.1 µg/mL. Meropenem volume of distribution was 0.35 ± 0.085 L/kg. CRRT clearance was 40.2 ± 6.6 mL/(min · 1.73 m(2) ) and accounted for 63.4% of the total clearance of 74.8 ± 36.9 mL/(min · 1.73 m(2) ). Simulations demonstrated that a dose of 20 mg/kg every 12 hours resulted in a time above the minimum inhibitory concentration (%fT > MIC) of 100% in 5 out of 7 subjects, with a %fT > MIC of 93% and 43% in the remaining 2 subjects. We conclude that CRRT contributed significantly to the total clearance of meropenem. A dosing regimen of 20 mg/kg achieved good target attainment in critically ill children receiving CRRT, which is consistent with our previously published in silico predictions.

Tolerable sorafenib therapy for a renal cell carcinoma patient with hemodialysis: a case study.

Sorafenib (Nexavar(®)) has been approved for the treatment of advanced renal cell carcinoma (RCC) and hepatocellular carcinoma. There is little information on the dosage adjustment of sorafenib for patients with end-stage renal failure. Herein, we have examined the effect of hemodialysis on the pharmacokinetics of sorafenib and its major active metabolite, M-2, and assessed sorafenib-related toxicity throughout the therapy. The patient was a 54-year-old man who was diagnosed with advanced RCC. Pharmacokinetic analysis was carried out on days 9 and 183. The patient had stable disease on day 77 and showed progression on day 181. He has received about 6 months of continuous treatment with sorafenib 800 mg/day without any clinically relevant toxicity. The pharmacokinetic parameters of sorafenib such as C (max) and AUC(0-12) on day 183 were in the range of the reference values reported in patients with normal renal function. Our results suggest that sorafenib administered at a dose of 400 mg twice per day was well tolerated, at least for 6 months, for a patient undergoing hemodialysis.

Neural correlates underlying perception of tonality-related emotional contents.

Using an event-related functional MRI technique, we examined the blood oxygen level-dependent responses of normal participants to auditory stimuli that consisted of four triads to explore the neural correlates for judging mode-related emotional contents in tonal music. Three categories of stimuli, MAJOR, MINOR and NEUTRAL were prepared. MAJOR and MINOR stimuli suggest C major and c minor, respectively. NEUTRAL stimuli were controls. The task was to judge the categories. Contrasts MAJOR-NEUTRAL and MINOR-NEUTRAL showed significant activation in the bilateral inferior frontal gyri, medial thalamus, and dorsal anterior cingulate cortex. It is suggested that the bilateral inferior frontal gyri and medial thalamus are involved in judging the mode, whereas the dorsal anterior cingulate cortex was related to conflicts in the participant's mind.