Interpretation of medication pictograms by adults in the UK

Patients' ability to understand information about medication is crucial for safety and effectiveness. Rates of illiteracy worldwide indicate that written information alone cannot meet many patients' needs. Medication pictograms are an alternative, but may be culturally sensitive. Previous testing has used large pictograms, which are impractical for conventional drug information formats.

To compare 2 sets of pictograms for instructions or warnings (from the US and South Africa) for understandability by adults in the UK and examine the effects of pictogram size and repeat presentation on understandability among older adults.

In the first part of the study, 160 adults (aged 17-83 y) reviewed and interpreted 10 pictograms. In the second, 67 older adults (aged 65-96 y) were randomly assigned to review 10 small or large pictograms. After giving their interpretation, they were informed of the correct meaning. One week later, they were shown the same pictograms and gave their interpretation.

The pictograms for the 10 different instructions and warnings showed great variation in interpretation rates (7.5-90%), with few significant differences between the US and South African versions. Only 3 were understood by > or = 85% of the population. Pictograms performed significantly better if they were larger and at the second presentation.

Pictograms have the potential to help patients understand information on drug therapy. This study shows that some existing pictograms are not easily interpreted and that testing is needed before their implementation. A reduction in their size to allow incorporation into conventional written formats may cause additional problems for patients.