Elliott C L, Read G F, Wallace E M
Department of Obstetrics and Gynaecology, University of Edinburgh, UK.
Acta Obstet Gynecol Scand. 1996 Mar;75(3):213-6. doi: 10.3109/00016349609047089.
To compare the pharmacokinetics of orally administered dexamethasone with intramuscular administration in antenatal patients at risk of preterm delivery.
Ten antenatal patients at risk for preterm delivery were given two intramuscular and then one oral dose of dexamethasone. Plasma which was collected at set intervals following the first intramuscular dose and the oral dose was assayed for dexamenthasone. The results were analyzed using pharmacokinetic data-fitting software and pharMacokinetic parameters calculated.
After oral adminIstration of dexamethasone the mean maximum plasma concentration obtained was 65% that of the intramuscular dose and the bioavailability of the oral route was calculated as 72% of the intramuscular route. The terminal half-lives of dexamethasone were similar for both routes.
These limited data would suggest that if dexamethasone is to be administered orally, which would be both preferable to patients and more economic, then a proportionately increased dose of oral dexamethasone would be required to provide similar maternal plasma pharmacokinetics to the intramuscular dose in current use. Further, larger studies are now required to confirm this.
比较口服地塞米松与肌肉注射地塞米松在有早产风险的产前患者中的药代动力学。
对10名有早产风险的产前患者先给予两次肌肉注射地塞米松，然后给予一次口服地塞米松。在首次肌肉注射剂量和口服剂量后的设定时间间隔采集血浆，检测其中的地塞米松。使用药代动力学数据拟合软件分析结果并计算药代动力学参数。
口服地塞米松后，测得的平均最大血浆浓度为肌肉注射剂量的65%，口服途径的生物利用度经计算为肌肉注射途径的72%。两种途径下地塞米松的终末半衰期相似。
这些有限的数据表明，如果要口服地塞米松，这对患者来说更可取且更经济，那么需要按比例增加口服地塞米松的剂量，以提供与当前使用的肌肉注射剂量相似的母体血浆药代动力学。此外，现在需要更大规模的研究来证实这一点。
