Antidiuretic Hormone

Antidiuretic hormone (ADH) is released from the pituitary gland in response to low blood pressure and increasing plasma osmolarity. ADH stimulates the reabsorption of free water in the kidneys by activating V2 receptors  (vasopressin receptor 2) in the kidney.  ADH also can stimulate V1 receptors (vasopressin receptor 1), which result in smooth muscle contraction, which also supports increasing blood pressure.  Vasopressin is used in the treatment of shock from vasodilatory states such as neurogenic shock and septic shock that is incompletely responsive to catecholamines.  

Desmopressin is used in the treatment of diabetes insipidus and nocturnal enuresis.  Diabetes insipidus is a condition where there is a decreased production or decreased response to ADH, which results in large loss of free water in the urine. Loss of large amounts of free water can result in dehydration and hypernatremia (high sodium levels).  Administration of desmopressin counteracts the ADH imbalance.  In nocturnal enuresis, urine production is decreased by the administration of desmopressin.

As expected, administration of ADH can result in hyponatremia due to reabsorption of free water.

Class Drugs

• Vasopressin

• Desmopressin

Class Mechanism of Action

V2 receptor agonist in the kidney

• Increases water reabsorption

V1 receptor agonist

• Stimulates vascular smooth muscle constriction

Class Applications

Diabetes insipidus

• Vasopressin results in increased reabsorption of free water

Bleeding esophageal varices (off-label)

• Reduces blood loss by vasoconstriction of blood vessels

Nocturnal enuresis

Class Adverse Effects

Hyponatremia

Drug Table

Drug Name	Application	Comments	Image
Vasopressin			"Vaseline" "Coffee Press"
Desmopressin	Used primarily in diabetes insipidus and nocturnal enuresis due to long half-life and lack of action at V1 receptor	Mechanism of Action; ; Minimal effect on V1 receptor, which results in less vasoconstriction	"Dessert" "Mop" "Coffee Press"