drug interactions could affect older adults

[Guest guest]

Dangerous drug interactions could affect millions of older adults,

study says

Even aspirin and dietary supplements can cause problems

By Deborah L. Shelton | Tribune reporter December 24, 2008

At least 2.2 million older adults in the U.S. take medicine in

combinations that could trigger dangerous drug interactions, causing

gastrointestinal bleeding, muscle breakdown, disruption in heart

rhythm and other serious problems, according to a new study by

researchers at the University of Chicago Medical Center.

Half of the interactions involved over-the-counter medications, such

as aspirin or dietary supplements.

Overall, 1 in 25 older adults risked serious drug interactions, the

study found. For men ages 75 to 85, it was as high as 1 in 10.

Study author Dr. Tessler u said risks might be even higher

because the research focused only on major interactions among the 20

most common drugs and dietary supplements.

" The public has an awareness that two prescription medications used

together might be dangerous, " said u, assistant professor of

geriatric medicine, obstetrics and gynecology at U. of C. Medical

Center. " But what people don't fully appreciate is that

non-prescription drugs can interact with prescription drugs and even

other non-prescription drugs. "

In the study, published in this week's Journal of the American Medical

Association, the most common problematic combination of

non-prescription drugs was ginkgo biloba and aspirin. Taking the two

together can increase the risk of internal bleeding, u said.

Adults 65 and older account for about 175,000 visits to the emergency

room annually for drug complications, and bleeding is frequently the

symptom that brings them to the hospital, u said.

Dr. Traci Muhammad said she deals with the problem of drug

interactions " every day, all day " in her Chicago internal medicine

practice.

" Patients will complain of muscle pain or weakness and then you see

that they are taking medications that shouldn't be taken together, "

said Muhammad, of ACCESS Booker Family Health Center on the South

Side. " It's very important for older patients to communicate with

their physicians so they can make sure none of their medications

interact with each other or with anything else they may be taking. "

The researchers used data collected for the National Social Life,

Health and Aging Project, a nationally representative survey of adults

57 to 85 administered between July 2005 and March 2006. They also

interviewed about 3,000 adults 65 and older at home, asking them about

the drugs they used regularly.

Of the respondents, 91 percent regularly used at least one medication,

a percentage that increased with age, and 29 percent took more than

five prescription drugs. Of those who took prescription drugs, 68

percent also used over-the-counter medications or dietary supplements,

such as vitamins or herbal remedies.

Mixing incompatible drugs can reduce their effectiveness or exaggerate

their side effects. For example, taking albuterol for asthma and

atenolol for high blood pressure together cuts the effectiveness of

both drugs.

Older people are taking more drugs than ever as a result of more

intense treatments for chronic illness, improved access to medications

through Medicare Part D, and the growth of the generic drug market,

the researchers said. Older people also are more likely to suffer from

multiple illnesses.

More than half of older adults now take five or more medications or

supplements, according to the study.

Study co-author Dima Qato said the elderly are more vulnerable than

others to the effects of bad drug combinations. " There are a lot of

physiological changes that affect drug metabolism—how the drug breaks

down in the body and how it interacts with the system, " Qato said.

Muhammad said some of her patients can't afford to buy medications and

sometimes take leftover medicines prescribed years earlier.

" Others think drugs are interchangeable and assume that if it is safe

to take one type of blood pressure medication with their other drugs,

it should be OK to exchange it for another one, " she said.

Herma Orr, 88, who has had two strokes, had been taking five

medications, including aspirin and warfarin (also known under the

brand name Coumadin). She didn't know that taking both drugs can

increase the risk of bleeding.

" I don't know what this medication does or that medicine does, " Orr said.

When she started seeing June McKoy, a geriatrician at Northwestern

Memorial Hospital, the doctor decreased Orr's dose of aspirin.

McKoy praised the new study but cautioned that the research did not

address that prescribing physicians might be aware of risks and were

monitoring the patient appropriately. Some drugs are prescribed

together for certain situations, she said.

u said the analysis did not find people taking drug combinations

that should not occur under any circumstances. She said the finding

indicated that drug safety systems used by health professionals are

working.

The study was financed with a pilot grant from the University of

Chicago Program in Pharmaceutical Policy, supported by the Merck

Foundation. Funding for the National Social Life, Health and Aging

Project study came from the National Institutes of Health.

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