Preswin 1 GM Injection is used in the treatment of bleeding esophageal varices (bleeding from dilated veins in the food pipe leading to your stomach). It narrows the walls of blood vessels and decreases the blood flow into the affected veins. Preswin 1 GM Injection is given by a healthcare professional. You should not self-administer this medicine at home. Your doctor will decide the dose and how often you should take them. It is given only to patients with severe or life-threatening bleeding in the food pipe (esophagus). Using this medicine can cause some common side effects such as headaches, slow heart rate, high blood pressure, peripheral vasoconstriction, and Peripheral ischemia low blood pressure. Let your doctor know if any of these side effects do not go away or get worse. Before using this medicine, inform your doctor if you have any problems with your heart, liver, or kidneys. You should also tell your doctor all the other medicines you are taking. This medicine is not recommended for children and adolescents.