Linsidomine (SIN-1, chemically 3-morpholinosydnonimin), is a vasodilator and antianginal drug. It is the direct hepatic metabolite of molsidomine. The dosage recommended by its manufacturer for its initial purpose, coronary angiography, is 0.4-1 mg. Contrary to molsidomine, which is widely used as an antianginal drug, linsidomine is used only for coronary angiography. The plasma half-life of Linsidomine is about 1 hour. Linsidomine is nonenzymatically metabolized to SIN-1A which spontaneously releases NO. NO, probably released directly from nonadrenergic, noncholinergic (NANC) nerves in the penis, is believed to cause smooth muscle relaxation by stimulating the soluble form of guanylate cyclase leading to an increase of intracellular cyclic guanosine 3',5' monophosphate (cGMP) with subsequent smooth muscle relaxation. Linsidomine also hyperpolarizes the cell membrane, making the smooth muscle less susceptible to adrenergic stimulation. NO further interacts with platelets when released intraluminally causing an increase in cGMP that decreases platelet aggregation and adhesion