Adverse drug events occur in over 15 percent
of older patients presenting to offices, hospitals, and extended care facilities.
Reactions to medications are responsible for 1 in 6 hospitalizations
among adults over age 65 and up to 1 in 3 hospitalizations
in adults over age 75.
Older adults are at particularly high risk of adverse drug events given physiologic changes of aging. Many medications prescribed for older adults are metabolized by the liver and kidney, which undergo changes as patients age. Blood flow in the liver decreases by 40 percent in older adults, affecting first-pass clearance of medications and requiring much lower doses of commonly prescribed drugs, including warfarin, benzodiazepines, and opiates.
Many older adults also present with impaired kidney function, decrease in serum protein, and poor nutritional status that affect absorption and utilization of medications.
These physiological changes are compounded by the effects of multiple medications. Older adults in developed countries take an average of 6 to 8 medications daily
, with risk of adverse drug events rising with each additional comorbid chronic illness.
Common serious effects of adverse drug events include falls, orthostatic hypotension, heart failure, and delirium. Patients with previous history of adverse drug events, nonadherence to medication, cognitive impairment, psychiatric disease, substance abuse, and those patients who live alone are all at increased risk of these adverse effects.
Adapted from Hartford Institute for Geriatric Nursing. ConsultGeri. Internet. Accessed on September 9, 2016.