Geriatric drug therapy.

Elderly Americans make up 11 percent of the population but consume 25 percent of all prescription medications. The incidence of adverse drug effect is 1.5 to 3 times higher in older patients and accounts for numerous hospitalizations. The basic pharmacokinetic parameters of absorption, distribution, metabolism, and excretion are all significantly altered in geriatric patients. Certain specific drug side effects, such as orthostatic hypotension and anticholinergic effects, can be particularly hazardous in older patients. This paper describes general therapeutic principles for geriatric patients. Commonly used drug categories are considered separately. A thorough knowledge of these principles will allow the physician to prescribe drugs more effectively, improve patient compliance, and minimize adverse drug effects.