Certain physiological changes associated with aging may affect the disposition and action of drugs within the body (see table below).

Physiological Changes Associated with Aging that Affect Drug Dynamics
Parameter	Physiological Change with Aging
Drug Absorption	stomach emptying
	stomach acidity
	gastrointestinal passage
	to spleen blood flow
	absorption through intestinal wall
Drug Distribution	cardiac output
	muscle mass
	body fat
Drug Elimination	activity of certain liver enzymes
	liver blood flow
	kidney blood flow and filtration rate