Used in the treatment of erectile dysfunction, often administered via injection into the penis to induce erection by increasing blood flow. Also utilized in neonatology to maintain patency of the ductus arteriosus in infants with certain congenital heart defects until corrective surgery can be performed. Applied in some cases of peripheral vascular disease to improve blood flow and reduce symptoms of ischemia. Investigated for use in preventing tissue damage after frostbite due to its vasodilatory and antiplatelet effects.