Perceived purpose of prescription drugs: the Iowa 65+ Rural Health Study.

In order to assess elderly patients' knowledge of their medications, the Iowa 65+ Rural Health Study asked a rural, elderly population the purpose of their prescription drugs. Ten percent of all drug purposes reported were considered inappropriate by our criteria. There was some variability between therapeutic categories and their frequency of purpose misperception. For 40 percent of drugs whose purpose was inappropriate, the respondent reported another drug for which that purpose would have been appropriate. Respondents were as likely to state a medication's appropriate purpose whether it had been dispensed by a pharmacy or a physician. The highest percentage of drugs whose purpose was appropriately perceived was dispensed by mail-order pharmacies.