Pharmacokinetic Evaluation of Gentamicin in Newborn Infants

新生兒期使用Gentamicin的藥物動態分析

林其和(Chi-Her Lin) ； 陳森輝(Shen-Hui Chen) ； 李慶雲(Chin-Yun Lee)

《Acta Paediatrica Sinica》 23卷3期 (1982/09) Pp. 148-155

摘要

革蘭氏陰性桿菌感染症爲新生兒期重要疾病之一。Gentamicin現在廣泛用以治療於新生兒感染症。由於生兒期內藥物之作用異於其他時期，此藥物使用於新生兒時期的評估實刻不容緩。本篇爲民國70年7月至12月間，47個於台大醫院小兒科住院，疑似或診斷爲細菌感染之新生兒，使用Gentamicin每劑2.5mg/kg後，依其年齡，體重及注射方式分羣比較其於新生兒血中濃度及半衰期的變化。本研究中，74個(88%)血中最高藥物濃度值在理想範圍內(4-10μg/ml)。8個(9.5%)所得最高濃度卻低於理想值。此外，15例(19%)血中最低值超過2μg/ml的所謂安全範圍值。由此可知，注射Gentamicin後，個人血中藥物濃度的變化很大。若欲有效且安全的達成治療的目的，必須不時檢驗血中藥物濃度。Gentamicin於新生兒期體內之半衰期與病兒年齡呈反比，但和體重及注射方式無關。對於5例腦膜炎患者，肌肉或靜脈注射Gentamicin後腦脊髓液內此抗生素濃度無法達到有效滅菌濃度。

並列摘要

A group of 49 newborn infants suspected or proven with bacterial infections, received gentamicin 2.5mg/kg every 8 or 12 hours, via intravenous or intramuscular route. The range of the peak serum levels was 3.0-12.8μg/ml. Suitable peak antibacterial levels (4-10μg/ml) were achieved in 74 (88%) of the total 84 specimens. Only in two specimens (2.3%) were the peak gentamicin levels grater than 12μg/ml, and in eight specimens (9.5%) below 4μg/ml. The range of trough serum levels was 0.5-4.3 μg/ml. In 15 (19%) of the total 84 specimens the trough values were greater than 2μg/ml, and in these 15 the serum creatinine levels, (mean 1.3 mg/dl) were higher than those in the rest (mean 0.9mg/dl). The wide individual variations in response to a given dose thus observed stress the necessity of monitoring the gentamicin concentrations in clinical practice. The half-lives of genlamicin following intravenous and intramuscular administration were significantly shorter (P＜0.05) in infants older than one week than in those younger, but were similar in the premature and mature infants. There were some evidences in this study suggesting that the drug may accumulate after the sixth dose. This was not yet confirmed and requires a further study. In full term infants under one week of age, the kidney function improved sharply after the fourth day of life contributing to the shortened half-lives with lower trough levels after the sixth dose. The mean peak cerebrospinal fluid gentamicin level obtained 4-6 hours after paarenleral gentamicin injection was only 1.5μg/ml, which was not high enough for the bactericidal effect. Gentamicin administered, either intravenous or intramuscular, yields similar pharmacokinetic results in newborn infants, thus intravenous infusion method can be applied when intramuscular injection are not desirable.

並列關鍵字

gentamicin ； newborns ； pharmacokinetics