Desmopressin

How it works

Desmopressin selectively activates renal V2 receptors to increase water reabsorption in the collecting ducts, concentrating urine, and also raises plasma factor VIII and von Willebrand factor.

Prescribing in practice

• The most important safety point is the risk of dilutional hyponatraemia and water intoxication; fluid intake must be restricted around dosing and the drug used with caution wherever fluid or electrolyte balance is disturbed.
• Withhold during acute intercurrent illness with vomiting or diarrhoea, or any condition causing fluid and electrolyte imbalance, and avoid in significant cardiac failure or conditions requiring diuretics.
• Risk of hyponatraemia is higher in the elderly and young children, so additional caution applies in these groups.

Monitoring

Monitor serum sodium, fluid balance, and body weight, especially when starting or up-titrating and in those at higher risk of hyponatraemia.

Counselling the patient

• Limit your fluid intake from shortly before until several hours after each dose, as advised.
• Stop the medicine and seek advice if you develop headache, nausea, vomiting, weight gain, or confusion.
• Pause treatment during any illness causing vomiting, diarrhoea, or fever until reviewed.

Evidence & guidelines

Desmopressin is the established first-line treatment for cranial diabetes insipidus, with the MHRA having issued warnings on the risk of severe hyponatraemia.