desmopressin

Desmopressin, also known as DDAVP, is a synthetic analogue of vasopressin (antidiuretic hormone) with predominant action at the V2 receptors. It increases water reabsorption in the renal collecting ducts, producing an antidiuretic effect, and can stimulate endothelial release of von Willebrand factor and factor VIII in some individuals.

Medical uses include central diabetes insipidus, where it reduces urine output and concentrates urine; nocturnal enuresis (bedwetting) in selected children and adults; and mild von Willebrand disease type 1 or mild haemophilia A, where it raises circulating levels of von Willebrand factor and factor VIII to aid hemostasis for surgery or dental procedures. It is not effective in nephrogenic diabetes insipidus and is generally not useful for peripheral or vascular causes of bleeding beyond its effect on factor VIII and von Willebrand factor.

Pharmacology and administration: desmopressin is given by intranasal spray, oral tablet, subcutaneous, or intravenous routes. Oral bioavailability is low due to first-pass metabolism; intranasal and parenteral forms are commonly used. The plasma half-life is a few hours, and urine concentration increases within minutes to hours depending on route. Its effects depend on hydration status and renal function.

Dosing varies by indication and patient age. For nocturnal enuresis, bedtime dosing is typical; for central diabetes insipidus, dosing is tailored to control polyuria and polydipsia; for bleeding disorders, dosing is timed around procedures and adjusted to achieve hemostatic factor levels.

Adverse effects include hyponatremia and water intoxication, headaches, nasal irritation with intranasal form, and facial flushing. Caution is advised in patients with reduced free water excretion, renal impairment, cardiac disease, or those consuming excessive fluids. NSAIDs and certain antidepressants can enhance the antidiuretic effect.