Safety and usage pattern of an over-the-counter ambroxol cough syrup:: a community pharmacy-based cohort study

Introduction: Mucoactive substances such as ambroxol, available in several countries as over-the-counter (OTC) medicines, are used for the treatment of acute and chronic bronchitis. Objective: This study was designed to evaluate the "real life" behavior of consumers with non-prescription access to an ambroxol cough syrup with special focus on tolerability and the pattern of product usage. Methods: Customers who bought the ambroxol syrup were recruited in 300 community pharmacies in Germany. Baseline data were collected from the participants in the pharmacy. Completing a self-administered questionnaire, participants provided information on tolerability, self-perceived effectiveness and usage pattern. Results: 2,707 participants were recruited in 266 pharmacies. 2,664 questionnaires were evaluable. At baseline, the respondents reported a complex pattern of symptoms. Productive cough, congested airways, dry cough, cough irritation in the throat and soreness in the throat were the most common ones. 67 patients (2.5%) reported a total of 81 adverse events (AE) which were usually mild in nature and mostly affecting the gastrointestinal tract (n = 53) followed by skin and subcutaneous tissue disorders (n = 9). No serious or unknown AE were reported. In general, 97% of the participants assessed the safety as "very good" (51%) or "good" (46%). Overall, the respondents complied with the indications for use and the recommended dosages, with only 0.7% of the participants using the maximum daily dose. 92% of the patients assessed the self-perceived effectiveness as "very good" (29%) or "good" (63%) and 89% were willing to purchase this ambroxol cough syrup again. Conclusions: This study confirms that ambroxol is used according to the advice given in the patients' leaflet and supports the already established safety and efficacy of this product in acute bronchitis. It also demonstrates that the use of an OTC cough medication can be successfully monitored in a pharmacy-based cohort study.