In this article, we are going to be looking at the physiological changes in the elderly that affect drug use.
Physiological changes in the elderly and pharmacokinetics of a particular drug determines the particular dosage of the drug to be used by the elderly.
Below are Age related changes that alters the therapeutic and toxic effects of drugs in the elderly;
Changes in body mass
the proportion of fat, lean tissues and water in the body change with age. Total body mass and lean body mass tend to decrease while the proportion of body fat tends to increase. This changes in the body composition affects the relationship between a drug’s concentration and distribution in the body.
Gastrointestinal function
there is decrease in gastric acid secretion and gastrointestinal motility in the elderly. All these reduce the emptying of stomach contents and movement through the entire intestinal tract. Elderly persons have been shown to have more difficulty in absorbing drugs than young people. This is a significant problem with drugs that have narrow therapeutic range in which small changes in dosage can be crucial.
Read Also: Importance of Geriatric Nutrition
Hepatic function
the liver’s ability to metabolize certain drugs decreases with age. The decrease is caused by diminish blood flow to the liver which results from an age related decrease in cardiac output, and from the lessened activities of certain liver enzymes.
Renal function
the ability to eliminate some drugs may be reduced by more than 50% in the elderly and most of the drugs used by the elderly are excreted primarily through the kidney. If the kidney’s ability to excrete drugs is decreased it will lead to high blood level of the drug.
Disease condition
the physiologic decline in organ function in the elderly is usually worsened by disease conditions. This leads to adverse drug reaction to drug as well as noncompliance
Age Related Changes That Affect Drug Therapy In The Elderly
- Decreased body water
- Decreased lean mass in the body.
- Increased body fat
- Decreased serum albumin level
- Altered homeostatic mechanism
- Altered receptor sensitivity.
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