Cloyd J C, Gumnit R J, Lesar T S
Ann Neurol. 1980 Feb;7(2):191-3. doi: 10.1002/ana.410070218.
Subtherapeutic phenytoin serum levels and loss of seizure control occurred in a 31-year-old man due to decreased bioavailability of oral drug. During storage at extreme temperatures, physical changes of the phenytoin capsule resulted in altered dissolution characteristics so that only 50% dissolution occurred at 180 minutes compared with 95% in 120 minutes for control capsules. Similar changes were produced in fresh capsules within seven days at high temperature and humidity. The affected patient has metabolic responses to phenytoin that produce marked fluctuations in serum levels with changes in dose. Altered phenytoin serum concentrations may occur with minor dose changes in such patients despite good compliance.
一名31岁男性因口服药物生物利用度降低，出现苯妥英血清水平低于治疗剂量且癫痫控制失效的情况。在极端温度下储存时，苯妥英胶囊的物理变化导致其溶出特性改变，在180分钟时仅有50%溶解，而对照胶囊在120分钟时的溶解率为95%。新鲜胶囊在高温高湿环境下7天内也会产生类似变化。该受影响患者对苯妥英有代谢反应，随着剂量变化血清水平会出现显著波动。尽管此类患者依从性良好，但剂量稍有变化就可能导致苯妥英血清浓度改变。
