Take two of these—or should that be three? Or one?

Congress recently took steps to improve the safety of children’s drugs. Now, a new study finds that those on the other end of the age spectrum also frequently receive medication that may put their health at risk.

Approximately 20 percent of prescriptions that primary care providers give to patients over the age of 65 are inappropriate, according to the study, published online August 22 in PLoS ONE. A medication is considered inappropriate if it has a higher risk of complication than a similarly effective drug, is insufficient to treat the problem for which it is prescribed, or is under-, over- or mis-prescribed. The researchers analyzed data from 19 previously conducted studies on prescription information for seniors.

"In spite of increasing attention to the quality of medication prescription among elderly persons presenting to the primary care setting, there are still high overall rates of inappropriate medication prescription," wrote the study authors, led by Dedan Opondo, of the medical informatics department at the University of Amsterdam.

The most common medications to get inappropriate scripts for the older set are: the pain-reliever Propoxyphene (Darvon), the antidepressant Amitriptiline (Elavil, Endep, Vanatrip), the beta-blocker Doxazosin (Cardura) and the antihistamine Diphenhydramine (Benadryl, etc.). Some of these frequently mis-prescribed meds, including antidepressants and antihistamines, can have serious adverse consequences when not taken correctly, especially in the senior population. Those over the age of 65 are more likely than younger patients to be taking several drugs that might interact; may have have poor kidney and liver function, which can effect drug metabolism; and may have "disabilities like visual and cognitive decline," which may put them at risk of accepting a prescription that is not right for them, the researchers noted.

The new meta-study only looked at seniors who lived in the community and not in assisted living or nursing homes. Previous analyses have found that some 40 percent of prescriptions given to those in nursing homes are not appropriate, possibly because nursing home patients are more likely to be on numerous medications. But is the rate is far too high.

The authors of the new study recommend continuing to push for more and better electronic decision-making tools, such as those that might accompany electronic health records. EHRs can track patients' histories and other medications more easily and send alerts if doctors are prescribing a medication that carries higher risks than a similar drug or might interact with a med the patient is already taking. Indeed, a 2010 study, published in the Archives of Internal Medicine, found that computer drug ordering systems helped reduce prescription errors—especially for those 66 and up.