Verbal descriptors of the frequency of side effects: implementation of EMA recommendations in patient information leaflets in Poland

Abstract

Background The European Medicines Agency (EMA) recommends a description of drug side effects based on the frequency format and the associated verbal description. Although the recommendations refer to English-speaking countries, in several non-English speaking states, official authorities have accepted the proposed recommendations on how the patient information leaflets should be designed for descriptions of side effect frequencies. The aim of the study was to examine how manufacturers of authorized medicines in Poland implement the EMA recommendations regarding the verbal descriptors of the frequency of side effects. Methods A qualitative study. As a first step, we identified which of the 150 pharmaceutical companies operating in Poland had the largest market share. Then, five manufacturers were selected at random from the list of the top fifteen drug manufacturers in Poland by market share of the pharmaceutical sector. Lists of medicinal products authorized for marketing in Poland were downloaded from manufacturers’ websites, and then five products from each manufacturer were selected based on random sampling. The study included only prescription medicines and excluded over-the-counter medicines and dietary supplements from the sample. Subsequently, for each of the 25 drugs relevant patient information leaflets were obtained from the manufacturers’ websites. We evaluated how information on the frequency of side effects was provided in each leaflet, including the use of EU-recommended terms (verbal descriptors such as "very common," "common," "uncommon," "rare," "very rare") and additional notes explaining their meanings. Results For all manufacturers, word labels of the frequencies of side effects selected for the study were the same but the additional notes explaining their meanings were different. There were various explanations of how to understand verbal descriptors of the frequency of side effects not only across different manufacturers but also across different medicines from one manufacturer. Conclusions There is no single standard in the Polish pharmaceutical industry for implementing the EMA recommendations into the written information about the frequency of side effects. The observed differences for an explanation of how to understand a given verbal term do not favor a uniform interpretation of the verbal frequency labels meaning by patients.