Nature and frequency of dosing instructions on prescription labels in primary care.

Abstract

To investigate the nature and frequency of dosing instructions and auxiliary labels on prescription labels in primary care. A retrospective analysis of data on prescription labels of dispensed drugs extracted from the pharmacy information system of community pharmacies in the Netherlands. Dosing instructions were categorized into four types. Data were extracted from 123 community pharmacies. All drugs dispensed for a random sample of 10% of patients were selected. In the sample of 938479 prescriptions, 96% had a predefined dosing instruction and 2995 different coded instructions were used. Ninety-five percent of all instructions were covered by 354 coded instructions. Most prescriptions were coded with an instruction indicating once daily use (48.4%) or twice or more times daily use (23.8%) without specification of the time (eg, "1 tablet 1 time a day"). A general instruction ("use as directed") was given for 7.0% of all prescriptions, and for 6.0%, the instruction was to use "as needed." For most prescriptions (80.6%), one or more auxiliary labels were generated with the warning "may cause drowsiness" (17.9%) being the most frequent one. A limited set of instructions covered the majority of the prescriptions. About a quarter of the prescription labels contained nonspecific dosing instructions for use multiple times a day, and 13.0% were general or "use as needed" instructions. These instructions can potentially be made more comprehensible by rewording and specification of the time of day.