Purpose: Clinicians use tamsulosin, an α1-adrenoceptor antagonist, to manage symptomatic benign prostatic hyperplasia (BPH). Because α1-adrenoceptors are also present in the brain, the potential exists for adverse effects on cognitive functions. We explored the association between tamsulosin use and dementia risk.

Methods: We used Medicare data (2006-2012) to conduct a cohort study among patients aged ≥65 years and diagnosed with BPH. Men taking tamsulosin (n = 253 136) were matched at a 1:1 ratio using propensity-scores to each of 6 comparison cohorts: patients who used no BPH-medication (n = 180 926), and patients who used the following alternative-BPH-medications: doxazosin (n = 28 581), terazosin (n = 23 858), alfuzosin (n = 17 934), dutasteride (n = 34 027), and finasteride (n = 38 767). Assessment began following the first fill of BPH-medication to identify incident dementia by ICD-9 diagnosis codes. We estimated hazard ratios (HR) and 95% confidence intervals (CI) for dementia using Cox proportional hazard regression for each of the 6 propensity-score-matched cohort-pairs.

Results: The median follow-up period for all cohorts was 19.8 months. After propensity-score matching, the tamsulosin cohort had an incidence of dementia of 31.3/1000 person-years compared with only 25.9/1000 person-years in the no-BPH-medication cohort. The risk of dementia was significantly higher in the tamsulosin cohort, when compared with the no-BPH-medication cohort (HR [95% CI]: 1.17 [1.14, 1.21]) and each of the alternative-BPH-medication cohorts: doxazosin (1.20 [1.12, 1.28]), terazosin (1.11 [1.04, 1.19]), alfuzosin (1.12 [1.03, 1.22]), dutasteride (1.26 [1.19, 1.34]), and finasteride (1.13 [1.07, 1.19]). The significance of these findings persisted in sensitivity analyses.

Conclusion: Tamsulosin may increase the risk of dementia in older men with BPH.