Alpha blockers are a type of blood pressure medicine. They stop a hormone called norepinephrine from tightening the muscles in the walls of smaller arteries and veins. So the blood vessels remain open and relaxed. This improves blood flow and lowers blood pressure.

Alpha blockers also relax other muscles in the body. So the medicines sometimes are used to treat symptoms of other conditions, such as an enlarged prostate.

Other names for alpha blockers are:

• Alpha-adrenergic blocking agents.
• Alpha-adrenergic antagonists.
• Adrenergic blocking agents.
• Alpha-blocking agents.
• Alpha-1 blockers.