Which adverse effects influence the dropout rate in selective serotonin reuptake inhibitor (SSRI) treatment? Results for 50,824 patients

Nowadays, selective serotonin reuptake inhibitors (SSRIs) are the most frequently prescribed antidepressants due to their superior clinical efficacy, effectiveness, tolerability, and safety as compared to tricyclic antidepressants or monoamino oxidase inhibitors. However, despite these advantages SSRIs are still associated with a number of adverse drug reactions, especially in the early stages of treatment, which may lead to premature discontinuation of therapy in some cases. The aim of the present study was to assess the most common adverse drug reactions of SSRIs as well as their impact on dropout rate in a large study population. Data for 50,824 patients treated for major depressive disorder with SSRIs for the first time was accessed via the Disease Analyzer database (IMS Health, Germany), providing information on SSRI adverse drug reactions and their influence on premature treatment discontinuation calculated by regression analysis. The presence of certain co-morbidities was also registered. The mean age was 54.5 ± 19 years, two-thirds of the study population being female. The adverse effects mentioned most frequently were: "discomfort" of the digestive system (10%), sleep disorders (8.6%), and heart rhythm disorders (4%); however, these were of tolerable severity as they did not significantly influence the dropout rate. Contrary to that, somnolence and younger age (≤50 years) in particular increased the chance of premature treatment discontinuation, while patients suffering from cardiovascular risk factors or osteoporosis tended to adhere to the therapy. Overall, there is high tolerability for early SSRI treatment, whereas the occurrence of somnolence leads to discontinuation.