Drug therapy in the elderly.

Age-related biologic and physiologic changes in the elderly may lead to altered pharmacokinetics. Volume of distribution, half-life, systemic clearance, and receptor sensitivity have been shown to change with increasing age. Unique features of illness in the elderly may interfere with effective drug therapy more than changed pharmacokinetics in some patients. Physical, psychologic, and socioeconomic considerations often interfere with ability to obtain and comply with health care. Disease is often difficult to recognize in elderly patients. Multiple chronic conditions, many of which may be undetected, may be exacerbated by or alter drug therapy for other illnesses. Cognitive impairment and diminished vision and hearing may make patient education difficult, and compliance poor. The elderly are also more susceptible to adverse drug reactions. The recommendations for clinical practice and directions for future research that are presented should help make drug therapy in the elderly safer and more effective.