Study released on drug interactions

December 23, 2008 3:38:40 PM PST
One in 25 older adults at risk for major drug interactions results from a national survey of older Americans (age 57 through 85) show that roughly half take prescription and over-the-counter drugs at the same time, and that 4 percent are at risk for serious drug interactions. People in the survey showed their medication bottles to an interviewer, who documented their use of prescription drugs, over-the-counter drugs, and dietary supplements. Results showed that 81 percent took at least 1 prescription medication, 42 percent used at least 1 over the counter medication, and 49% used a dietary supplement.

About 4 percent took drugs that could interact in dangerous ways; the most common possible dangerous interaction involved the blood thinner Warfarin, which can have decreased effectiveness when paired with the statin Zocor and increased risk for bleeding when paired with aspirin.

They're common prescription and non-prescription medications. But when taken in combination, they can cause problems for the most vulnerable among us: older adults.

"The number of medications older adults are taking are increasing and we worry about the potential interactions between these drugs because they may have some safety implications for older adults," said Dr. Stacy Tessler, of the University of Chicago Medical Center.

Combining drugs can result in internal bleeding, among other serious problems.

"Combinations of medications may reduce the effectiveness of one or the other medication," adds Dr. Tessler.

Dr. Tessler decided to look at medication use among older adults.

The study analyzed data collected from over 3,000 people between the ages 57-85 about their use of prescription drugs like blood-thinners over-the-counter drugs, such as aspirin and vitamins and herbal supplements, like ginkgo biloba.

The study found that nearly one in 25 people, four percent were at risk for major, hazardous drug interaction.

Dr. Tessler adds, "One of the important findings is that, specifically for older men, ages 75-85, one in 10 were using combinations of drugs that put them at risk for a severe medication interaction."

Researchers recommend that doctors and pharmacists be careful when prescribing and dispensing drugs, and that patients take precautions, too.

"They have to make sure they discuss all their medications with their physician and their pharmacist," said Dr. Tessler.

Pharmacist, Dima Qato adds, "Not only the prescription medications, but also the medications they buy over-the-counter."