Isosorbide Dinitrate (ISDN, Sorbide nitrate, Sorbidnitrate, Isordil, Nitrosorbide) is the dinitrate salt form of isosorbide, an organic nitrate with vasodilator activity. Isosorbide Dinitrate is a medication used for heart failure, esophageal spasms, and to treat and prevent chest pain from not enough blood flow to the heart. Isosorbide Dinitrate can converte to nitric oxide (NO), an active intermediate compound which activates the enzyme guanylate cyclase (atrial natriuretic peptide receptor A).