When doctors prescribe antibiotics for older people, they may prescribe a lower dose than usual because the kidneys tend to function less well as people age. In such cases, the kidneys may not be able to eliminate antibiotics from the body as effectively, increasing the risk of side effects. (See also Aging and Drugs.)

Doctors also consider the following:

• What other drugs the person is taking because older people tend to take many drugs and drug interactions are a risk

• Whether the antibiotic regimen is complex and hard to follow

• Whether the person has family members or caregivers who can help the person take the antibiotic as prescribed

• Whether the person lives in a nursing home because different bacteria may cause infections in such situations