Evaluation of syncope association with α1-adrenoceptor blockers in males using the FAERS database: impact of concomitant hypertension.

Previous studies have revealed an association between the administration of alpha1-adrenoceptor blockers (alpha1Bs) and episodes of syncope in patients with benign prostatic hyperplasia (BPH). The objective of the present study was to evaluate the association between alpha1Bs and syncope in BPH patients with hypertension using two different pharmacoepidemiological indices. Using the US Food and Drug Administration Adverse Event Reporting System, we analyzed the whole dataset and subsets for specific indications, including hypertension, diabetes, and dyslipidemia, for males older than 40 years. The drugs of interest were alfuzosin, doxazosin, and terazosin as non-selective alpha1Bs and silodosin and tamsulosin as selective alpha1Bs. The reporting odds ratio (ROR) and information component (IC) were used for signal detection. The association between the non-selective alpha1Bs and syncope was observed for all the items examined. The results obtained using the whole dataset, as well as the diabetes and dyslipidemia subsets, were same for the selective and non-selective alpha1Bs in terms of the association with syncope, while no association with syncope was observed for both silodosin [ROR: 1.09, 95% confidence interval (CI): 0.61-1.93; IC: 0.10, 95% CI: -0.72-0.92] and tamsulosin (ROR: 1.08, 95% CI: 0.90-1.30; IC: 0.10, 95% CI: -0.17-0.37) in patients with hypertension. The data suggested that alpha1Bs, even those with receptor subtype selectivity, were associated with syncope. Thus, careful attention should be paid when prescribing alpha1Bs, especially to patients who do not take medications for hypertension.