DDAVP is a synthetic version of the antidiuretic hormone secreted by the pituitary gland. The hormone regulates kidney function; an increase in the hormone will slow urine production (when your body is dehydrated) and a decrease in the hormone allows urine production to increase (when your body needs to get rid of excess water). The hormone is also normally produced during sleep to slow urine production enough to allow you to make it through the night without having to pee. Bedwetters sometimes don’t produce enough of the hormone and DDAVP helps by slowing urine production even more. It helps most people with bedwetting problems but is not a cure, bedwetting will return immediately if you stop taking it. Even if it works for you, you will still have occasional wet nights, especially if you drink more than normal during the evening. It is also expensive (over $100 per month) so it helps to have good prescription drug insurance.