Disproportionality Analysis of Hypotension-Related Adverse Drug Reactions Associated with Type 1a Selective Alpha Blockers in VigiBase

Some evidence suggests no association between type 1a (T1a) selective alpha-blockers and hypotension-related adverse drug reactions (HR-ADRs), although safety concerns still exist. We sought to investigate the association of HR-ADRs with selective T1a blockers and identify at-risk groups. We used disproportionality analysis to detect signals of HR-ADRs (dizziness, fainting, falls, fractures) reported with selective T1a blocker use in VigiBase, a global database of individual case safety reports. Excluding duplicates, all reports were included (1967 to 2022). Significance was determined using lower bound 95% Empiric Bayes Estimator >1; only then were reporting odds ratios (ROR) and 95% confidence intervals (CI) reported. Subgroup analyses were stratified by sex, age (<65 and ≥65 years), and indication for men only (urinary stone disease [USD] and benign prostatic hyperplasia [BPH]). We identified 5963 reports of HR-ADRs with selective T1a blockers. Selective T1a blockers were significantly associated with HR-ADRs (ROR 1.46; 95% CI 1.42-1.49). In men, selective T1a blockers for USD were associated with increased risk of HR-ADRs (ROR 1.60; 95% CI 1.56-1.65), which only remained significant in the older subgroup (ROR 6.70; 95% CI 3.20-14.01). No association was found for BPH. In women, selective T1a blockers were associated with an increased risk of HR-ADRs (ROR 1.09; 95% CI 0.99-1.09). This was only significant in the younger subgroup (ROR 1.17; 95% CI 1.03-1.32). In older men with USD and younger women, selective T1a blockers were associated with higher risk of HR-ADRs, suggesting continued monitoring in these populations is needed. No signal was observed for men with BPH.