Delafuente Jeffrey C
Virginia Commonwealth University School of Pharmacy, Richmond, VA 23298-0581, USA.
Consult Pharm. 2008 Apr;23(4):324-34. doi: 10.4140/tcp.n.2008.324.
Adverse drug events (ADEs) are all too common in older patients. Although there are multiple causes for the ADEs in the elderly, alterations in pharmacokinetics (PK) and pharmacodynamics (PD) are frequent culprits. These alterations in PK and PD may be part of the normal aging process. Older patients often develop significant drug-related problems when alterations in PK and PD are not appropriately accounted for in prescribing and monitoring of medications. Clinically, the most significant PK changes that occur in aging are renal elimination and metabolism of drugs. In general, renal function declines with aging, necessitating dosage adjustments for drugs with renal-elimination pathways. The ability of the liver to metabolize certain drugs may also decline as a consequence of the aging process. From a PD standpoint, exaggerated responses are frequent, and often it is the side effects of medications that become exaggerated, rather than the therapeutic effects. Drugs affecting the central nervous system are particularly prone to PD alterations. Because of the PK and PD changes, vigilant monitoring of both therapeutic and adverse effects is mandatory in older patients. Based on PK and PD differences between middle-aged and elderly patients, there are certain medications that should almost always be avoided in older people. In addition, because older people tend to use more medications, the incidence of drug-drug interactions becomes more prevalent. Most of the drug-drug interactions that adversely impact older people involve both PK and PD mechanisms. Pharmacists and all prescribers must have a sound understanding of PK and PD effects of medications used in older people to provide optimal care and avoid preventable drug-related problems.
药物不良事件（ADEs）在老年患者中极为常见。尽管老年人发生ADEs有多种原因，但药代动力学（PK）和药效学（PD）的改变是常见的罪魁祸首。PK和PD的这些改变可能是正常衰老过程的一部分。在药物处方和监测中，若未适当考虑PK和PD的改变，老年患者往往会出现严重的药物相关问题。临床上，衰老过程中发生的最显著的PK变化是药物的肾脏排泄和代谢。一般来说，肾功能会随着年龄增长而下降，因此需要对经肾脏排泄的药物进行剂量调整。肝脏代谢某些药物的能力也可能因衰老过程而下降。从PD的角度来看，过度反应很常见，而且往往是药物的副作用变得过度，而非治疗效果。影响中枢神经系统的药物尤其容易出现PD改变。由于PK和PD的变化，对老年患者的治疗效果和不良反应进行密切监测是必不可少的。基于中年和老年患者之间的PK和PD差异，有些药物在老年人中几乎应始终避免使用。此外，由于老年人往往使用更多药物，药物相互作用的发生率变得更高。大多数对老年人产生不利影响的药物相互作用都涉及PK和PD机制。药剂师和所有开处方的医生必须充分了解老年人使用药物的PK和PD效应，以提供最佳护理并避免可预防的药物相关问题。
