A study comparing the effectiveness of three warning labels on the package of driving-impairing medicines

Several medicines are known to potentially impair patients' driving fitness. Appropriate communication towards patients about this risk can be supported by the use of package warning labels.

To compare the effectiveness of a standing practice yellow/black label-with written warning-with a newly developed rating model in communicating risk on driving-impairing medicines (DIMs). Furthermore, the added value of a side-text in the rating model was determined.

Community pharmacies in the Netherlands.

In a cross-sectional study, patients with a first dispensing of a DIM were asked by their community pharmacists (n = 38) to fill out a written questionnaire to compare each of the three warning labels. A 2 [yellow/black label vs. rating model (pair 1) and rating model with side-text vs. rating model without side-text (pair 2)] × 3 [category of driving-impairment: I = minor risk, II = moderate risk, III = severe risk] design was used. The category of driving-impairment varied per respondent, depending on the DIM the patient collected.

(1) estimated level of driving risk valued by patients (2) intention to change driving behaviour after seeing the warning label.

An estimated number of 992 patients were approached. As 298 questionnaires were analysed, the net response rate was 30%. With the yellow/black label, respondents considered DIMs of all three categories of driving-impairment to equally impair driving fitness, while with the rating model the estimated risk was higher when the category referred to a higher level of driving-impairment. Addition of a side-text to the rating model resulted in a significantly higher estimated level of driving risk and a significant increase in intention to change driving behaviour. Only 8.0% of the patients using a category III DIM estimated the level of driving risk correctly when seeing the yellow/black label, while this was 26.7% for the rating model and 43.0% for the rating model with side-text.

The yellow/black label, which is standing practice in the Netherlands, is less effective in terms of estimated risk and intention to change driving behaviour, compared to a newly developed rating model. This model is even more effective when a side-text is added. Implementation of the rating model in clinical practice should be considered.