Egerman R S, Pierce W F, Andersen R N, Umstot E S, Carr T L, Sibai B M
Department of Obstetrics and Gynecology, University of Tennessee, Memphis, USA.
Obstet Gynecol. 1997 Feb;89(2):276-80. doi: 10.1016/S0029-7844(96)00446-2.
To compare the bioavailability of oral and intramuscular (i.m.) dexamethasone in third-trimester pregnant women.
Oral and i.m. dexamethasone levels were compared in a randomized, parallel, crossover bioavailability study involving 11 gravid women in the third trimester of pregnancy. Subjects were randomized to receive either 6 mg of i.m. or 8 mg of oral dexamethasone. The following week, the alternative regimen was administered. Serial blood samples were obtained after drug administration. Dexamethasone concentrations were measured by radioimmunoassay. Total area under the curve was compared for the oral and i.m. groups using a paired t test.
Eight of the 11 women completed the study through 12 hours; all 11 women completed the study through 6 hours. Among the 11 women, peak levels of dexamethasone occurred 30 minutes after i.m. injection (mean +/- standard deviation, 101.7 +/- 19.2 ng/mL) and 120 minutes after oral administration (65.9 +/- 20.5 ng/mL). Area under the curve did not differ significantly between those receiving i.m. dexamethasone (258.3 +/- 50.0 ng/minute/mL) and those receiving oral dexamethasone (251.8 +/- 59.7 ng/minute/mL) when measured 6 hours after administration of the drug. Terminal half-lives were similar in the i.m. and oral groups. Similar findings were noted among the eight women who were studied through 12 hours. This study had a power of 87% to detect a 20% difference in area under the curve between the two groups.
The bioavailability of 8 mg of oral dexamethasone is similar to that of a 6-mg IM dose, as determined by the area under the curve.
比较孕晚期妇女口服和肌内注射地塞米松的生物利用度。
在一项随机、平行、交叉生物利用度研究中，对11名孕晚期孕妇的口服和肌内注射地塞米松水平进行比较。受试者被随机分为接受6mg肌内注射或8mg口服地塞米松。下周，给予替代方案。给药后采集系列血样。用地放射免疫法测定地塞米松浓度。使用配对t检验比较口服组和肌内注射组的曲线下总面积。
11名女性中有8名完成了12小时的研究；所有11名女性完成了6小时的研究。在这11名女性中，地塞米松的峰值水平在肌内注射后30分钟出现（平均值±标准差，101.7±19.2ng/mL），口服给药后120分钟出现（65.9±20.5ng/mL）。给药6小时后，接受肌内注射地塞米松的患者（258.3±50.0ng/分钟/mL）和接受口服地塞米松的患者（251.8±59.7ng/分钟/mL）的曲线下面积无显著差异。肌内注射组和口服组的终末半衰期相似。在进行了12小时研究的8名女性中也观察到了类似的结果。本研究有87%的把握检测出两组曲线下面积有20%的差异。
根据曲线下面积测定，8mg口服地塞米松的生物利用度与6mg肌内注射剂量相似。
