Ticagrelor safety profile in real-life setting of acute coronary syndrome patients

We read with great interest the paper by Chen et al, the first of its kind that investigated the efficacy and safety of ticagrelor versus clopidogrel in patients with acute coronary syndrome (ACS) in Asia (including Taiwan) in a real-life clinical setting. In their analysis, the authors reported that a higher number of patients treated with ticagrelor experienced dyspnea as compared with those patients treated with clopidogrel in both overall (25.0% vs. 14.6%, p< 0.001) and propensity-matched (21.0% vs. 11.6%, p1⁄4 0.01) cohorts. Furthermore, they affirmed that the incidence of dyspnearelated discontinuation of P2Y12 antagonist treatment tended to be higher in the ticagrelor group by propensity score matching. In particular, their study showed that when compared with clopidogrel treatment, ticagrelor causes a fourfold increase in the incidence of dyspnea and required discontinuation of a P2Y12 antagonist. During our intensive pharmacovigilance activities in emergency departments (EDs), we encountered several cases of dyspnea associated with ticagrelor treatment. In particular, we observed a case of severe paroxysmal nocturnal dyspnea developed in a poststenting 90-year-old man associated with the first use of ticagrelor. We then conducted a retrospective cohort study in the EDs of the Florence (Italy) metropolitan area to define the occurrence rate of dyspnea leading to ED admission in ACS for patients treated with ticagrelor. Among communitydwelling patients who were prescribed ticagrelor from 2012e2014, the overall dyspnea occurrence was about 2% (1.86%, 20/1073 patients). All cases of outpatient dyspnea were severe and caused an ED admission. The median time between the first prescription of ticagrelor and the onset of dyspnea was 47 days (interquartile range: 10e185). Although the clinical data showed that ticagrelor treatment is generally well-tolerated and discontinuation rates are comparable to those observed for clopidogrel, the Chen et al observational study fits perfectly within this context, since