Desmopressin is used to control the symptoms of a certain type of diabetes insipidus (‘water diabetes’; condition in which the body produces an abnormally large amount of urine). Desmopressin is also used to control excessive thirst and the passage of an abnormally large amount of urine that may occur after a head injury or after certain types of surgery. Desmopressin is also used to control bed-wetting. Desmopressin is in a class of medications called hormones. It works by replacing vasopressin, a hormone that is normally produced in the body to help balance the amount of water and salt.
Desmopressin comes as a tablet to take by mouth. It is usually taken two to three times a day. When desmopressin is used to treat bed-wetting, it is usually taken once a day at bedtime. Try to take desmopressin at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take desmopressin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Summary from MedlinePlus.gov, click for more information.