[Factors related to purchasing over-the-counter medications online]

We conducted a Web-based survey of approximately 40,000 Internet users on the purchase of over-the-counter (OTC) medications online in March 2009. The valid response rate was 97.8% and the number of responses was 39,208. The number of people who had purchased OTC medications online was 4,653 (11.9%), prescription medicines 792 (2.0%), and medical contact lenses 1,993 (5.1%). As a result of the multiple logistic regression analysis, independent variables with odds ratios (ORs) >1.5 were experience of purchasing prescription-only medicine online (OR=4.997, 95%CI=4.288-5.824), regular supplement use (OR=2.384, 95%CI=2.233-2.548), experience of purchasing colored contact lenses online (OR=2.206, 95%CI=1.632-2.983), no time to visit drugstores (OR=2.092, 95%CI=1.928-2.270), usage of Web sites of uncertain reliability (OR=1.992, 95%CI=1.857-2.137), and experience of purchasing therapeutic contact lenses online (OR=1.796, 95%CI=1.597-2.020). As some people have purchased prescription-only medicine or medical devices and had problems with drug information sources, the development of awareness of medical and pharmaceutical supplies and health and medical information literacy are key priorities to ensure safe OTC medication sales systems.