Decrease of voriconazole trough levels during therapy with enteral nutrition: a case report.

BACKGROUND: Voriconazole (VRCZ) is the first-line therapy for chronic pulmonary aspergillosis and is available in both intravenous and oral formulations. The bioavailability of the oral form is estimated to be over 90% in healthy volunteers. Some drugs are reported to interact with enteral nutrition (EN), but there are few reports about the trough levels of VRCZ during EN therapy. Here, we describe changes in the VRCZ trough levels in a patient receiving continuous EN therapy. CASE PRESENTATION: The patient was a 58-year-old man with esophageal cancer and a history of partial pulmonary resection due to aspergilloma. He was taking oral VRCZ tablets and his VRCZ trough level was about 2 µg/mL before esophageal cancer surgery. Following esophagectomy, VRCZ was restarted on postoperative day 16. Crushed VRCZ tablets were administered via a jejunostomy tube because of swallowing difficulty. He was also receiving EN, which was interrupted only during the administration of VRCZ. When we checked his VRCZ level 5 days after restarting VRCZ, the trough level was 0.80 µg/mL. After increasing the VRCZ dose, reducing EN, and changing the administration route from jejunostomy tube to oral, his trough level increased to 1.87 µg/mL. CONCLUSIONS: A decrease in the VRCZ trough level was observed when VRCZ was administered via a jejunostomy tube while the patient was receiving continuous EN. Careful monitoring of VRCZ levels is needed in such cases.

Population Pharmacokinetics of Vancomycin Under Continuous Renal Replacement Therapy Using a Polymethylmethacrylate Hemofilter.

BACKGROUND: Although continuous hemodiafiltration (CHDF) is often performed in critically ill patients during sepsis treatment, the pharmacokinetics of vancomycin (VCM) during CHDF with a polymethylmethacrylate hemofilter (PMMA-CHDF) have not been revealed. In this study, the authors aimed to describe the population pharmacokinetics of VCM in critically ill patients undergoing PMMA-CHDF and clarify its hemofilter clearance (CLhemofilter). METHODS: This single-center, retrospective study enrolled patients who underwent intravenous VCM therapy during PMMA-CHDF at the intensive care unit of Chiba University Hospital between 2008 and 2016. A population analysis was performed, and CLhemofilter was assessed. RESULTS: Twenty-five patients were enrolled. Median body weight (BW) and Sequential Organ Failure Assessment (SOFA) score were 63 kg and 15, respectively. Mean conditions for CHDF were 107.5 ± 18.3 mL/min for blood flow rate and 26.3 ± 6.3 mL/kg/h for effluent flow rate. The mean parameter estimates were distribution volume of the central compartment (V1), 59.1 L; clearance of the central compartment (CL1), 1.35 L/h; distribution volume of the peripheral compartment (V2), 56.1 L; and clearance of the peripheral compartment (CL2), 3.65 L/h. BW and SOFA score were significantly associated with V1 (P < 0.05) and CL1 (P < 0.05), respectively, and were thus selected as covariates in the final model. The estimated dosage of VCM to achieve a target area under the concentration-time curve/minimum inhibitory concentration ≥400 was 27.1 mg/kg for loading and 9.7 mg/kg every 24 hours for maintenance; these dosages were affected by BW and SOFA score. Mean CLhemofilter obtained from 8 patients was 1.35 L/h, which was similar to CL1. CONCLUSIONS: The authors clarified the pharmacokinetics and CLhemofilter of VCM in PMMA-CHDF patients. The PK of VCM in patients undergoing CHDF appeared to vary not only with the CHDF setting and BW but also with SOFA score.

Dasatinib can Impair Left Ventricular Mechanical Function But May Lack Proarrhythmic Effect: A Proposal of Non-clinical Guidance for Predicting Clinical Cardiovascular Adverse Events of Tyrosine Kinase Inhibitors.

Tyrosine kinase inhibitors are known to clinically induce various types of cardiovascular adverse events; however, it is still difficult to predict them at preclinical stage. In order to explore how to better predict such drug-induced cardiovascular adverse events, we tried to develop a new protocol by assessing acute electrophysiological, cardiohemodynamic, and cytotoxic effects of dasatinib in vivo and in vitro. Dasatinib at 0.03 and 0.3 mg/kg was intravenously administered to the halothane-anesthetized dogs for 10 min with an interval of 20 min between the dosing (n = 4). Meanwhile, that at 0.1, 0.3, and 1 µM was cumulatively applied to the human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) (n = 7). In the dogs, the low and high doses provided peak plasma concentrations of 40 ± 5 (0.08) and 615 ± 38 ng/mL (1.26 µM), respectively. The low dose decreased the heart rate, impaired the left ventricular mechanical function, and prolonged the ventricular effective refractory period. The high dose prolonged the repolarization period, induced hemorrhagic tendency, and increased plasma cardiac troponin I level in addition to enhancement of the changes observed after the low dose, whereas it neither affected the cardiac conduction nor induced ventricular arrhythmias. In the hiPSC-CMs, dasatinib prolonged the repolarization and refractory periods like in dogs, while it did not induce apoptotic or necrotic process, but that it increased the conduction speed. Clinically observed major cardiovascular adverse events of dasatinib were observed qualitatively by currently proposed assay protocol, which may become a useful guide for predicting the cardiotoxicity of new tyrosine kinase inhibitors.

Effects of continuous ingestion of green tea or grape seed extracts on the pharmacokinetics of midazolam.

Limited systematic data on herb-drug interaction are available, despite many opportunities to concomitant use of herb with prescribed drugs. We investigated the effects of 15 herbal extracts in dietary supplements on CYP2C9, CYP2D6 and CYP3A4 activities in human liver microsomes. Strong inhibition of these CYP activities was found by the addition of green tea extracts (GTE) or grape seed extracts (GSE) in vitro. To examine the effects of these extracts on CYP3A activities in vivo, the pharmacokinetics of midazolam (MDZ) was analyzed in rats. Although single treatments with these extracts had negligible effects, 1 week of treatment with them resulted in a significant increase in the ke of intravenously administered MDZ, indicating the induction of CYP3A in the liver. In contrast, 1 week of treatment with GTE, but not GSE, caused a significant increase in the C(max) and AUC(0-infinity) of orally administered MDZ without change in the t(1/2), suggesting a reduction in CYP3A activity in the small intestines. These studies indicate that subchronic ingestion of GTE or GSE may alter the pharmacokinetics of MDZ, and the effects of GTE on CYP3A activity appear opposite between liver and small intestine, which could not be predicted from in vitro experiments.

Effects of Kampo extracts on drug metabolism in rat liver microsomes: Rhei Rhizoma extract and Glycyrrhizae Radix extract inhibit drug oxidation.

In the present study, the effects on drug oxidations in rat liver microsomes in vitro using 126 Kampo extracts were investigated. Although the effects of inhibition on drug oxidations were dependent on the Kampo extracts and probe reactions studied, most of the Kampo extracts showed inhibitory effects on both N-demethylations of aminopyrine and erythromycin in rat liver microsomes. Among the Kampo extracts studied herein, Daio-kanzo-to exhibited the most remarkable inhibitory effect on both reactions. The Rhei Rhizoma extract inhibited not only aminopyrine and erythromycin N-demethylations, but also phenacetin O-deethylation, 7-ethoxycoumarin O-deethylation, ethanol oxidation and tolbutamide 4-hydroxylation in rat liver microsomes. The Glycyrrhizae Radix extract also showed a remarkable inhibitory effect on phenacetin O-deethylation as well as aminopyrine and erythromycin N-demethylations. In contrast, the Glycyrrhizae Radix extract virtually showed no effect on ethanol oxidation.