Cardura Tab 4mg is a prescription medication primarily used to treat high blood pressure (hypertension) and symptoms of benign prostatic hyperplasia (BPH) in men. The active ingredient, doxazosin mesylate, belongs to a class of drugs called alpha-1 adrenergic antagonists. It works by relaxing the blood vessels so blood can flow more easily, which helps to lower blood pressure. Additionally, These tablets help to relax the muscles in the prostate and bladder neck, which can relieve symptoms such as difficulty urinating, frequent urination, and weak urine flow associated with BPH.