Hytrin(terazosin) is used alone or with other drugs to treat high blood pressure (hypertension). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. This medication works by relaxing blood vessels so blood can flow more easily. Terazosin is also used in men to treat the symptoms of an enlarged prostate (benign prostatic hyperplasia-BPH). It does not shrink the prostate, but it works by relaxing the muscles in the prostate and part of the bladder. This helps to relieve symptoms of BPH such as difficulty in beginning the flow of urine, weak stream, and the need to urinate frequently or urgently (including during the middle of the night). Terazosin belongs to a class of drugs known as alpha blockers.