Isoxsuprine belongs to the group of medicines called vasodilators. Vasodilators increase the size of blood vessels. Isoxsuprine is used to treat problems resulting from poor blood circulation. It may also be used for other conditions as determined by your doctor. Isoxsuprine causes direct relaxation of uterine and vascular smooth muscle. Its vasodilating actions are greater on the arteries supplying skeletal muscle than on those supplying skin. It is used in the treatment of peripheral vascular disease and in premature labor.