Imdur Tablet 30's are organic nitrates with blood vessel dilatation activity. It is used to treat angina pectoris, a heart condition in which blood vessels in the heart narrow unexpectedly and suddenly, resulting in decreased blood flow to the heart muscles, causing suffocation and a tight pain in the chest, neck, or arm area. Isosorbide mononitrate is a powerful vasodilator (widens blood vessels). It works by the formation of the free radical nitric oxide (NO) within our bodies, which leads to the relaxation of blood vessel muscles, particularly those of the heart, allowing proper blood flow to the heart muscle, which has been working under tremendous strain.Disclaimer:For More Information Contact Your Physician