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Is Polypharmacy Harming Your Patients?
Abstract & commentary
By Joseph E. Scherger, MD, MPH, Clinical Professor, University of California, San Diego. Dr. Scherger reports no financial relationship to this field of study.
Synopsis: One in 25 older Americans, and almost 10% of older men, are at risk for serious health problems such as bleeding and muscle weakness because they take an unwise combination of medications; half the time a non-prescription medication is involved.
Source: Qato DM, et al. Use of prescription and over-the-counter medications and dietary supplements among older adults in the United States. JAMA 2008;300:2867-2878.
A research group from the university of chicago conducted in-home surveys of medication use among a representative sample of 3005 Americans aged 57-85 years. These older Americans were on about 15,000 different medications! Overall, 4% were on potentially risky combinations of medications for harmful drug-drug interactions and half of these involved the use of non-prescription medications. Men in the older age group (75-85 years) had the greatest risk, about 10%, and nearly half of that involved the use of anticoagulants. The actual risk of harm may be greater than this survey suggests since only the top 20 prescription and non-prescription medications were studied.
The most common potentially harmful drug-drug interactions were: lisinopril and potassium increasing the risk of hyperkalemia; aspirin and warfarin increasing the risk of bleeding; aspirin and ginkgo increasing the risk of bleeding; and simvastatin and warfarin increasing the risk of bleeding and rhabdomyolysis. Some combinations decreased the effectiveness of both drugs, such as albuterol with atenolol or metoprolol.
The authors conclude with emphasis on the importance of physicians and pharmacists asking about all the medications a person is taking, including prescription and non-prescription medications, and educating patients about appropriate and inappropriate combinations.
Polypharmacy has made a comeback from a recent time when taking many medications was considered a risk factor for harm. A single common chronic disease like diabetes usually results in our patients taking 4 or 5 medications. Add hypertension, lipid disorder, heart disease, and arthritis and you have a recipe for potentially harmful medication interactions. Add to that the multi-billion dollar supplement industry and it is no wonder than many of our patients are harmed from risky medication combinations.
Memorizing all drug-drug interactions is not possible and information support is necessary for us and our patients. Good computerized drug-drug interaction programs are available and we should use them liberally at the point of care. Increasingly, patients will have drug-drug interaction programs on their home computers.
More important is open and complete information about what our patients are taking. Computerized personal health records kept by our patients and shared with providers will help with medication disclosure. We should encourage our patients to use them. Applications such as Google Health and Microsoft Healthvault may play an increasingly important role in medication safety.
Most important, in my opinion, is to have a philosophy about medication use that less is better. When I hear that older patients are on more than 10 medications, I cannot help but believe that all these may be doing more harm than good. Getting patients off medications should be a goal as much as or more than prescribing them. Lifestyle improvements such as exercise and weight loss may allow us to reduce the number of medications our patients are taking.
The dietary supplement industry, which is protected from needing to give accurate health information, is a duplicate therapy system that many of our patients believe is harmless and may be helpful. When we have patients on a therapeutic regimen of multiple medications, we need to be proactive in talking about supplements and know exactly what our patients are taking, and caution them to avoid adding to the regimen with non-prescription products.
The Institute of Medicine estimates that there are 1.5 million adverse drug events in the United States every year.1 These occur in office practices, hospitals, and long-term care facilities. It may be that the patient's home is the riskiest place for harmful medication use. Only by getting patients actively involved with reporting and managing their medication use will we get a handle on the pervasive problem of harm from medications.
1. Institute of Medicine. Preventing Medicine Errors. Washington DC: National Academy Press; 2006.