Perucca E
Clin Pharmacokinet. 1984 Jan;9 Suppl 1:71-8. doi: 10.2165/00003088-198400091-00009.
The free fraction of phenytoin, carbamazepine and valproic acid shows considerable interindividual variability, especially in the presence of associated disease or drug interactions. When binding is altered, the total concentration no longer reflects the amount of pharmacologically active drug in the plasma: this may mislead the clinician into making inappropriate dosage adjustments. Measuring the free drug concentration eliminates a potential source of interpretative errors and may be preferentially used to monitor therapy in selected patients.
苯妥英钠、卡马西平和丙戊酸的游离部分存在相当大的个体间差异，尤其是在伴有相关疾病或药物相互作用的情况下。当蛋白结合发生改变时，总浓度不再反映血浆中具有药理活性的药物量：这可能会误导临床医生做出不适当的剂量调整。测定游离药物浓度可消除一个潜在的解释误差来源，在特定患者中监测治疗时可优先使用。
