DDAVP, 1-desamino-8-d-arginine-vasopressin, is a synthetic analogue of vasopressin with increased antidiuretic activity and decreased pressor activity. Whereas the antidiuretic-to-pressor ratio of arginine vasopressin is 1, the antidiuretic-to-pressor ratio of DDAVP is 4000. When administered as an intranasal spray, 5 to 20 mug of DDAVP produced eight to 20 hours of antidiuresis in patients with complete central diabetes insipidus. The minimum recommended therapeutic dose resulted in a maximum antidiuresis in most patients. No side effects of the drug were noted in clinical trials. DDAVP thus gives promise of becoming the standard treatment of severe central diabetes insipidus.