Dickinson R G, Hooper W D, Patterson M, Eadie M J, Maguire B
Ther Drug Monit. 1985;7(3):283-9. doi: 10.1097/00007691-198507030-00008.
Urinary excretion of p-hydroxyphenytoin and its glucuronide conjugate was measured in eight healthy young adults in a comparative bioavailability study of oral sodium phenytoin (approximately 5 mg/kg/dose). Among these subjects the percentage of the phenytoin dose converted to p-hydroxyphenytoin and appearing in urine was relatively similar (mean 79%, range 67-88%). The great majority of the p-hydroxyphenytoin appeared in urine as conjugates; only 1.4-3.4% of the excreted p-hydroxyphenytoin was in the form of unconjugated metabolite. The proportion of a single phenytoin dose excreted in urine as p-hydroxyphenytoin or its conjugate increased from the first dose (mean +/- SD) 74.9 +/- 4.6% to the second dose, given 2 weeks later 79.3 +/- 4.6% (p less than 0.05). This finding suggests that autoinduction of phenytoin metabolism may occur after relatively brief exposure to the drug.
在一项口服苯妥英钠（约5mg/kg/剂量）的相对生物利用度研究中，对8名健康年轻成年人测定了对羟基苯妥英及其葡萄糖醛酸结合物的尿排泄量。在这些受试者中，转化为对羟基苯妥英并出现在尿液中的苯妥英剂量百分比相对相似（平均79%，范围67 - 88%）。绝大多数对羟基苯妥英以结合物形式出现在尿液中；排泄出的对羟基苯妥英中只有1.4 - 3.4%是以未结合代谢物的形式存在。作为对羟基苯妥英或其结合物在尿液中排泄的单一苯妥英剂量比例从第一剂（平均值±标准差）74.9±4.6%增加到2周后给予的第二剂的79.3±4.6%（p<0.05）。这一发现表明，在相对短期接触该药物后可能会发生苯妥英代谢的自身诱导。
