December 24, 2008
Study Examines Drug Combination Effects On Elderly
U.S. researchers said on Tuesday that older adults in the United States are taking prescription pills, over-the-counter drugs and dietary supplements in record numbers, and in combinations that could pose serious health risks.
Over half of U.S. adults aged 57 to 85 are using five or more prescription or non-prescription drugs, and one in 25 are taking them in combinations that could cause dangerous drug interactions, researchers said.
Dr. Stacy Tessler Lindau of the University of Chicago Medical Center in Illinois acknowledged that older adults in the United States use a lot of medicine. "While medications are often beneficial, they are not always safe," she said.
Her study appears in the Journal of the American Medical Association.
A recent report estimated that U.S. adults over 65 make up more than 175,000 emergency room visits a year for adverse drug reactions, and commonly prescribed drugs accounted for a third of these visits.
For the study, the researchers used data from a national survey of adults aged 57 to 85 and interviews with nearly 3,000 people in their homes to better understand what medications they used on a regular basis.
After analyzing the potential interactions among the top 20 prescription and over-the-counter drugs and the top 20 dietary supplements, the researchers found that 68 percent of adults surveyed who took prescription drugs also used over-the-counter drugs or dietary supplements.
"One in 10 men between the ages of 75 to 85 were at risk for a drug-to-drug interaction," Qato said.
They found that nearly half of the potential drug-to-drug interactions could cause bleeding problems. The blood thinner warfarin, often sold by Bristol-Myers Squibb Co. under the brand name Coumadin, was most commonly cited in potentially dangerous combinations.
Warfarin is commonly prescribed after a heart attack, stroke or major surgery and nearly 2 million people in the U.S. take it. The team found warfarin was commonly teamed up with aspirin, a drug often taken to prevent heart attacks that also interferes with clotting.
The cholesterol-lowering statin drug simvastatin, which is sold by Merck & Co under the brand name Zocor, and Warfarin were another combination that could cause potential bleeding risks.
Many people were also taking the popular nutritional supplement Ginkgo biloba in combination with aspirin, another potential cause of bleeding in non-prescription drugs.
However, they found no instances of people taking absolutely forbidden drug combinations, but the finding of widespread use of drugs that could cause major drug reactions caused some concern.
Qato believes the patient needs to know about such risks. He recommended patients carry a list in a wallet or purse of all of the drugs and supplements they take.
Doctors, pharmacists and other health professionals should also remember to ask about all of the medications their patients are taking.
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