Comparative User Testing of Australian and UK Over-the-Counter Labels and Leaflets for Diclofenac

Background: Limited research has evaluated the consumer usability of written information available with similar over-the-counter (OTC) products in different countries. This study evaluated the usability of labels and leaflets for Australian and UK OTC diclofenac products and explored consumer perspectives on their design, content, usability, and potential improvements. Methods: Australian and UK OTC diclofenac products were selected for user testing. Demographically matched groups of Australian and UK consumers were recruited to user test each label and leaflet set to determine whether 9 salient clinical messages could be found and understood. Consumer perspectives on the tested label and leaflet were explored using semistructured interviews as part of user testing. Results: Forty consumers user tested the Voltaren Rapid 25 (Australia) and Voltarol Pain-eze Extra Strength 25-mg tablets (UK) information (10 participants per brand per country). Dosage, maximum daily dose, and contraindications information was found and understood by most (>= 9/10 per group), except the Voltaren dosage which was misunderstood by 4/20. However, 12/20 could not locate the maximum duration of continuous use in the Voltaren leaflet. Participants had difficulty determining that another nonsteroidal anti-inflammatory drug could not be used with diclofenac (7/20 and 9/20 understood this in the Voltaren and Voltarol groups, respectively). Suggested label and leaflet improvements included increased font size, bolding/highlighting, and color. Conclusion: When evaluated in both countries, not all key clinical information was effectively communicated by information accompanying Australian and UK diclofenac products. Improvements in how information is communicated are needed.