Rapaflo 4 mg is a brand name for silodosin, a medication used to treat symptoms of benign prostatic hyperplasia (BPH) in men. BPH is a condition where the prostate gland enlarges, leading to urinary difficulties such as frequent urination, weak stream, and incomplete bladder emptying. Silodosin works by relaxing the muscles in the prostate and bladder neck, improving urine flow and reducing symptoms associated with BPH.