Oral ingestion of a topical benzydamine hydrochloride-containing gynaecological preparation in association with television advertising in Italy: analysis of cases managed by a National Poison Control Centre

OBJECTIVE: To evaluate the impact of a television advertising campaign on the risk of oral ingestion of a topical non-prescription gynaecological preparation containing benzydamine hydrochloride. DESIGN: An interrupted time series design with data routinely collected. SETTING: A National Poison Control Centre. PARTICIPANTS: 215 cases of hazardous exposure to the preparation under study occurred in Italy from January 2005 to December 2010. PRIMARY AND SECONDARY OUTCOME MEASURES: Mean daily rate of cases of exposure by gender in three different periods, that is, pre-advertisement period, before the advertisement was broadcast (from 1 January 2005 to 19 December 2009), advertisement period, when the advertisement was repeatedly launched (from 20 December 2009 to 27 February 2010), post-advertisement period (from 28 February 2010 to 6 March 2010); observed/expected ratios of cases, with expected cases based on data from the pre-advertisement period, adjusted for estimated variations in the number of users. Comparison of the distribution of the main characteristics of cases in the three different periods by means of Pearson's χ(2) test or Fisher's exact test. RESULTS: The adjusted observed/expected ratio of cases in women was 7.48 (95% CI 5.76 to 9.56) in the advertisement period and 2.97 (95% CI 2.24 to 3.85) in the post-advertisement period. Regarding the characteristics of cases, there was an increased proportion of cases of exposure due to confusion about the correct administration route in the advertisement and post-advertisement periods (81% and 55%, respectively, compared to 16% for the pre-advertisement period.) and of individuals with clinical effects (55%, 52% and 27%, respectively). CONCLUSIONS: In Italy, an advertisement for a non-prescription medicine seems to have confused consumers regarding the administration route. This effect was observed even after the advertisement had stopped being broadcast. These results highlight the need for the monitoring of medication errors and adverse effects before, during and after advertising.