In the United States the population over 85 years of age use a disproportionately large percentage of health care resources, including drugs. The elderly take approximately one-third of all medications. Among other factors, the need for several agents predisposes them to adverse drug reactions and drug interactions. Sequelae from drug usage in the elderly are more common than in younger patient populations, and often result in hospitalization. Careful patient monitoring is imperative for optimum pharmacotherapy in elderly patients.