Millions of older adults in U.S. at high risk for drug interactions

WASHINGTON, Dec. 25 (Chinese media) -- At least one in 25

older adults, or about 2.2 million people in the United States, take multiple

drugs in combinations that can produce a harmful drug-drug interaction, and half

of these interactions involve a non-prescription medication, researchers from

the University of Chicago have reported in the current issue of JAMA.

The study used data collected for the National Social

Life, Health and Aging Project, a survey of adults aged 57 to 85 conducted

between July 2005 and March 2006. The survey team interviewed 3,005 participants

in their homes about the medications they used "on a regular schedule, like

every day or every week."

Although the number of people taking medications has

remained stable for the last decade, the number of drugs taken by older people

has significantly increased.

Ninety-one percent of all respondents regularly used

at least one medication, a percentage that increased with age. Twenty-nine

percent of older adults took more than five prescription medications.

This may be a result of more intense therapy for

chronic illness, improved access to medications, and the growth of the generic

drug market, said the study.

Sixty-eight percent of the adults who took

prescription drugs also used over-the-counter medications or dietary

supplements.

"Older adults are the largest consumer of

prescription drugs," said study author Stacy Tessler Lindau. "We find that they

commonly combine these prescription medications with over-the-counter

medications and dietary supplements, which can increase their vulnerability to

medication side-effects and drug-drug interactions."

Nearly half of the drug-drug interactions identified

could cause bleeding problems, said the researchers. One of the most common was

taking warfarin, a prescription drug designed to prevent blood clots, along with

an over-the-counter drug such as aspirin, which also interferes with clotting.

"Physicians and pharmacists need to ask their

patients about the use of nonprescription medications," said Lindau. "Patients

need to inform their providers about all medications they use --- prescription

and nonprescription -- and should ask their physician or pharmacist about

interactions any time they start a new drug, on their own or following the

doctor's recommendation."