Hamilton, Ontario—Pharmacists see it all the time: Patients begin taking drugs intended for short-term use and never seem to stop.

Now, new Canadian research warns that medications taken indefinitely—even though they are not intended for that—can be a big contributor to overmedication, especially in the elderly.

The report in Annals of Family Medicine looked at nearly 51,000 adults in and around Hamilton, Ontario, to document rates of “legacy prescribing,” i.e., medications that are not appropriately discontinued when their usefulness has diminished and when the risk of side effects, interactions with other drugs, and ongoing costs remain.

Specifically, the McMaster University–led study team calculated rates of legacy prescribing for three classes of medications:
• Antidepressants (continuous prescribing of more than 15 months)
• Bisphosphonates (continuous prescribing of more than 5.5 years)
• Proton pump inhibitors (continuous prescribing of more than 15 months)

The population-based retrospective cohort study used data from the McMaster University Sentinel and Information Collaboration (MUSIC) Primary Care Practice Based Research Network, located in Hamilton, Ontario, and included all adult patients, aged 18 years or older in the MUSIC data set from 2010 to 2016.

Results indicate that the percentage of patients receiving a legacy prescription at some time during the study period was 46% for antidepressants, 14% for bisphosphonates, and 45% for proton pump inhibitors (PPIs). In addition, many of those patients held current prescriptions.

“The mean duration of prescribing for all legacy prescriptions was significantly longer than that for non-legacy prescriptions (P <.001). Concurrent legacy prescriptions for both antidepressants and PPIs was common, signaling a potential prescribing cascade,” the researchers pointed out.

“The phenomenon of legacy prescribing appears prevalent,” the study authors concluded. “These data demonstrate the potential of legacy prescribing to contribute to unnecessary polypharmacy, providing an opportunity for system-level intervention in primary care with enormous potential benefit for patients.”

The study notes a lack of recognition that the duration of medication is a source of inappropriate prescribing, adding that prescribing systems tend to be geared toward starting and continuing drug therapy. In fact, researchers add, most of those systems have no controls to flag the end of an intermediate-term prescription, although routine represcribing systems and software features are common.

The authors urge system-oriented change involving prescribing systems, education, and communication between patients, pharmacists and physicians on appropriately stopping drug therapy.

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