The synthetic agent, 1-deamino-8-D-arginine vasopressin (DDAVP), is generally regarded to be the treatment of choice for persons with type I von Willebrand disease (vWD), and may be useful in type IIA vWD as well. Several formulations of the drug are available, including a highly concentrated intranasal spray formulation which is ideal for home use. The degree of F VIII and vWF response to DDAVP varies among individuals, but is generally consistent in individual patients over time. Some have tachyphylaxis while others do not. While side effects are uncommon, DDAVP is a potent antidiuretic agent. Thus one should be aware of the possibility of hyponatremia and water intoxication if certain precautions are not observed.