Title: Oral Phenytoin Loading
题目：苯妥英钠的口服负荷剂量
Author 作者: Bryan Hayes

We often see seizure patients on phenytoin therapy who have subtherapeutic levels.  Most patients do not require intravenous loading and can be adequately managed with oral treatment.
我们经常会遇见一些服用苯妥英钠不够量的癫痫病人，多数这样的病人可给予口服负荷量，并不需要静脉给药。
To estimate what dose to prescribe, use the following equation: [0.7 x IBW x (15 - current level)].  For example if a 70 kg patient has a level of 8 mcg/mL (mg/L), we would need ~400 mg loading dose to achieve a level of 15.
估算所需口服剂量，可用下列公式：<0.7x理想体重x（15－现在血浆浓度）>。列如：一个苯妥英钠血浆浓度为8毫微克／毫升（毫克／升）的70岁的病人，需要口服大约400毫克的负荷量以达到15的血浆浓度。
Phenytoin is known for its erratic absorption and propensity for causing GI upset with doses too high.  The recommended strategy is to avoid administering more than 400 mg at one time and separate the doses by 2 hours.  This would take three doses over 4 hours for a 1 gm load.
苯妥英钠的消化道吸收是不稳定的，并且剂量太大可导致消化道症状。建议方法是避免一次剂量超过400毫克，可隔2个小说重复给药。这样 1克的口服负荷量可通过3次在4小时内完成。
In the ED, an effective strategy for a 1 gm oral load is 500 mg now and 500 mg in 2 hours at discharge.  Patients tolerate it well, it cuts down on ED length of stay, and still achieves therapeutic levels.  Remember that an oral suspension formulation is also available.
在急诊科，需要1克口服负荷量的有效方法是立即给500毫克，然后2小时出院时再给500毫克。病人对这样的方法耐受很好，在达到治疗浓度同时缩短了急诊科停留时间。记住，苯妥英钠也有克服的液剂。