Background: The clarity of prescription drug instructions is a health literacy and medication safety concern.
Objective: To assess the variability of pharmacy interpretations of physician prescriptions.
Design: Identically written prescriptions for 4 common medications (atorvastatin, alendronate, trimethoprim/sulfamethoxazole, ibuprofen) were filled in 6 pharmacies (2 largest chains, 2 grocery stores, 2 independents) in 4 cities (Boston, Chicago, Los Angeles, Austin).
Measurement: Components of the instruction were coded as dose, frequency, administration route, timing, indication, and auxiliary instructions.
Results: In all, 85 labels were evaluated. Dose frequency was omitted on 6% of instructions ("take 1 tablet for cholesterol"). Timing was explicitly stated on 2% of instructions ("in the morning"). All prescriptions included indications; pharmacies transcribed these onto 38% of labels. The prescription for alendronate stated not to lie down for at least 30 minutes after taking; this was transcribed with 50% of instructions. Reading difficulty was above recommended levels for 46% of instructions; with 14% greater than a high school level.
Conclusions: Efforts are needed to ensure patients receive clear, consistent information supporting safe medication use.