Used primarily to treat high blood pressure (hypertension) by relaxing blood vessels, allowing blood to flow more easily and reducing the workload on the heart. It is also prescribed for managing symptoms of benign prostatic hyperplasia (enlarged prostate) in men, helping to improve urine flow by relaxing muscles in the prostate and bladder neck. Additionally, it has been used off-label for the treatment of post-traumatic stress disorder (PTSD), particularly to reduce nightmares and improve sleep quality. Its action as a selective alpha-1 blocker makes it effective in lowering vascular resistance without significantly increasing heart rate.