Serum concentration of oral midazolam as pediatric preanesthetic medication and factors related to the sedation level.

BACKGROUND: Preanesthetic medication is important to eliminate surgical anxiety in pediatric patients and facilitate their smooth transfer to the operating room. Midazolam is the most commonly used preanesthetic medication. However, it has been reported that the sedative effect varies from patient to patient. In this study, the pharmacokinetics of midazolam were examined, and the aim was to assess the factors affecting the quality of sedation. METHODS: The participants were children ranging in age from 6 months to 8 years scheduled for surgery. Midazolam 0.5 mg/kg was administered orally 30 min before entering the operating room, and the sedation level was evaluated at the time of mask application. Blood was collected after slow induction, and the serum concentration of midazolam was measured using high-performance liquid chromatography. RESULTS: A total of 98 patients were registered. There was no difference in serum concentrations between the effective sedation group and the ineffective sedation group (48.0 vs. 49.1 ng/mL), regardless of the effect of midazolam. Percentages of ineffective sedation by age (0 to 7 years) were 66.6%, 60%, 33.3%, 11.1%, 0%, 0%, 12.5%, and 0%, respectively. On multivariate logistic regression analysis, siblings (OR = 3.9, CI: 1.1-14.0, p = .03) and age (OR = 3.2, CI:1.2-8.5, p = .02) were related to an insufficient sedative effect. CONCLUSION: The serum concentration of oral midazolam reached effective levels even in patients in whom the sedative effect was inadequate. It is important to manage the perioperative period with appropriate concurrent premedication taking into account patient age and social background characteristics. CLINICAL TRIAL REGISTRATION: Clinical trial registry: UMIN R000052504.

Initial trough concentration may be beneficial in preventing linezolid-induced thrombocytopenia.

We assessed whether prospective therapeutic drug monitoring to optimise the therapeutic range could prevent linezolid-induced thrombocytopenia. This prospective interventional study was conducted from September 2017 to October 2020 among 37 adult patients receiving linezolid. Patients were administered one of the following two initial dosages: 600 mg twice or once daily for patients with a creatinine clearance rate of ≥50 or <50 mL/min, respectively. Linezolid dosage adjustment was performed on days 3-5 based on the trough concentration. The serum linezolid levels in 22 and 15 patients were within and above the therapeutic range (2-7 µg/mL), respectively. The incidence of thrombocytopenia was significantly lower among patients whose linezolid levels were within the therapeutic range (4.5%;1/22) than in those whose levels were above the therapeutic range (80%; 12/15). It is important to maintain the linezolid level within the therapeutic range at the first therapeutic drug monitoring to prevent thrombocytopenia.