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Variation in Prescribing Instructions Confuses Patients on Multidrug Regimens

March/April, 2011, Vol 4, No 2

Every physician has a preferred way of writing prescription instructions, and pharmacists differ in how they translate those instructions to the pill bottle. A study published in the Annals of Internal Medicine by Wolf and associates found that the lack of a universal medication schedule (UMS) to standardize how prescriptions are written and filled contributes to poor patient adherence and increases safety concerns. Elderly patients or those with low health literacy are more prone to confusion when trying to follow a multidrug regimen.

In a 2008 report, “Standardizing Medication Labels,” the Institute of Medicine (IOM) recommended implementing a UMS to reduce misunderstandings related to medication use. Noting that 90% of prescriptions require no more than 4 daily doses, the IOM called for delineating 4 standard dosage times—morning, noon, evening, and bedtime—to help patients taking multiple drugs to consolidate doses. Reception to the proposal was mixed, with calls for more research.

To determine whether a UMS was needed, investigators assessed the ability of 464 patients aged 55 to 74 years to adhere to a hypothetical 7-drug prescription regimen. The patients were part of a broader study that incorporated a 2-hour interview to evaluate their adeptness at performing everyday health tasks. Most (84%) had at least 1 chronic health condition; approximately 61% were college educated and an equal proportion had household incomes >$50,000.

Researchers gave every patient prescription bottles containing fake pills and mock labels for 7 retired drugs; dosing instructions varied between the drugs. Patients also received a pill box with 24 slots marked with consecutive 1-hour intervals, going from 12:00 AM to 11:00 PM. Each patient was verbally instructed to “imagine that your doctor has prescribed you these medications. I would like you to please show me when you would take these medicines over the course of 1 day,” and offered additional instruction as needed. Although the drugs could be neatly consolidated into 4 dosing intervals, participants sorted them into an average of 6 slots. Some consolidated the regimen into as few as 3 dosing periods, whereas others used as many as 14 slots. One-third of patients indicated 7 intervals each day for taking drugs; 14.9% indicated 4 times or fewer.

Labels for 3 drugs had identical dosing instructions and could therefore have been taken simultaneously, yet one-third of patients failed to do so. Another 2 drugs required thrice-daily dosing, with 1 stipulating to take it with food and water. Only 50.5% of participants scheduled them to be taken together. Another 2 drugs needed to be taken twice a day; the label for one said “twice daily” and the other said “every 12 hours.” In all, 79% of patients failed to consolidate them into concurrent dosing intervals.

For drugs calling for twice-daily dosing, an average of 10.3 hours elapsed between doses (range, 1 hour to 18 hours). For thrice-daily dosing, a mean of 5.4 hours elapsed between the first and second doses and 6.5 hours between the second and third doses.

Low health literacy—ascribed to 20.7% of patients—was the only factor that independently predicted a greater likelihood of taking medications more than 7 times per day. Patients with low health literacy and no chronic conditions had the worst rate of efficient consolidation.

The authors said strategies are needed to help patients understand how to take prescriptions and how to consolidate multiple prescriptions. They said adopting a UMS could “unite medical and pharmacological practice” and suggested that an electronic health records system could be used to facilitate standardization in prescribing. They also recommended educating providers on how to identify patients likely to have trouble adhering to a complicated regimen

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