Thursday, August 21, 2014

HOW AGE AFFECTS DRUG ACTION

As the body ages, body structures and systems change, affecting how the body responds to medications. Some common changes that significantly affect medication administration follow.
Body composition
As a person grows older, his total body mass and lean body mass tend to decrease while body fat tends to increase. These factors affect the relationship between a drug's concentration and solubility in the body.
Digestive system
Decreases in gastric acid secretion and GI motility lead to the body's decreased ability to absorb many drugs well. This can cause problems with certain drugs—for example, digoxin, whose narrow therapeutic range is tied closely to absorption.
Hepatic system
Advancing age reduces blood supply, and certain liver enzymes become less active. As a result, the liver loses some of its ability to metabolize drugs. With reduced liver function comes more intense drug effects as higher levels of a drug remain in circulation. This increases the incidence of drug toxicity.
Renal system
Kidney function diminishes with age. This alone may impair drug elimination by 50% or more. In many cases, decreased kidney function leads to increased blood levels of certain drugs.

0 comments:

Post a Comment

Powered by Blogger.

Search This Blog