Arteries are blood vessels that carry blood from the heart to the rest of the body. Blood pressure is fairly easy to measure. The pressure is related to blood flow inside the arteries, much like the pressure inside a hose is related to water flowing through it.
Many conditions can cause low blood pressure.
Low blood pressure may or may not cause symptoms. Many symptoms get worse when the person stands. Other symptoms depend on the cause. In this case, the medication may work too well and make the blood pressure too low. Many other medications, such as the sedative diazepam or amitriptyline, which is used to treat depression , can cause low blood pressure in some people.