Piette F, Soubrie C
Service de médecine interne-gérontologie, hôpital Charles-Foix, Ivry-sur-Seine.
Rev Prat. 1990 May 21;40(15):1359-65.
A knowledge of pharmacokinetic data is particularly important with drugs that have a narrow margin of safety. Exhaustive pre-marketing pharmacokinetic investigations and pharmacokinetic studies in populations are the two principal means of acquiring such knowledge. Although popular, the concept of half-life which decreases with age for many drugs is insufficient to calculate dosage in elderly people. Measurements of creatinine clearance provide an almost mathematical approach to the dosage of drugs that are excreted exclusively by the kidneys. In contrast, changes in hepatic metabolism with age and pathology are difficult to evaluate, and their consequences are often vaguely perceived. Our knowledge of relationships between age and pharmacodynamics is still in infancy. Owing to the wide consumption of medicine by elderly people, drug interactions are frequent at all stages, including absorption, metabolization, transport and site of action.
对于安全范围较窄的药物而言，了解药代动力学数据尤为重要。详尽的上市前药代动力学研究以及针对特定人群的药代动力学研究是获取此类知识的两种主要途径。尽管半衰期的概念广为人知，且许多药物的半衰期会随着年龄增长而缩短，但这一概念并不足以用于计算老年人的用药剂量。测量肌酐清除率为仅通过肾脏排泄的药物剂量计算提供了一种近乎精确的方法。相比之下，随着年龄增长和病理变化，肝脏代谢的改变难以评估，其后果也常常难以确切察觉。我们对年龄与药效学之间关系的了解仍处于起步阶段。由于老年人用药量较大，药物相互作用在包括吸收、代谢、转运和作用部位在内的各个阶段都很常见。
