How does aging affect pharmacokinetics?

Aging indeed affects pharmacokinetics, which refers to how the body handles a drug through processes such as absorption, distribution, metabolism, and excretion. This is due to several physiological changes that occur with age.

As individuals age, there are changes in gastrointestinal function, such as decreased gastric acid production and slower gastric emptying, which can alter drug absorption. The distribution of drugs is also affected; for instance, changes in body composition—such as increased body fat and decreased lean body mass—can influence the volume of distribution for lipophilic and hydrophilic drugs differently.

Metabolism, primarily occurring in the liver, can decline with age, leading to a slower rate of drug clearance. This is particularly relevant for drugs that have a high hepatic clearance. Similarly, renal function tends to decline in older adults, impacting the excretion phase of pharmacokinetics. Reduced glomerular filtration rate means that drugs that are primarily eliminated via urine may require dose adjustments to prevent toxicity.

Each of these factors contributes significantly to how the elderly respond to medications and emphasizes the importance of individualized therapy in this population. Understanding these changes allows healthcare providers to optimize drug therapy and minimize adverse effects as patients age.