The risk of fractures, acute myocardial infarction, atrial fibrillation and ventricular arrhythmia in geriatric patients exposed to promethazine

Objectives: This study aimed to compare the risk of fractures, acute myocardial infarction, atrial fibrillation, and ventricular arrhythmia among Danish citizens aged >= 65 which were new users of promethazine or domperidone, triazolam, loratadine, and betahistine. Secondly, the study aimed to perform a risk stratification to identify the most relevant predictors for the study outcomes. Methods: The study period was 01/01/2015 to 31/12/2016. The data sources were the Danish registers. Each patient was followed for 90 days. A logistic regression model was used to compute the unadjusted and adjusted odds ratios (OR), and a conditional inference tree was used to identify the most relevant predictors for the study outcomes. Results: Promethazine had a higher risk of hospitalization for atrial fibrillation than loratadine and betahistine (OR 1.58; 95% CI 1.07-2.63 and OR 3.22; 95% CI 1.69-7.14, respectively). For fractures, acute myocardial infarction, and ventricular arrhythmia hospitalizations, no statistically significant differences were found among drugs under investigation. The medical history of cardiac arrhythmia (OR 4.14; 95% CI 2.94-5.78, p < 0.0001) was the most relevant predictor for atrial fibrillation hospitalizations. Conclusion: This study found an increased risk of atrial fibrillation hospitalization among promethazine users, and the risk was higher among patients with prior cardiac arrhythmia.