Desmopressin (DDAVP)

How it works

It is a selective V2 receptor agonist that promotes renal water reabsorption and triggers release of von Willebrand factor and factor VIII from endothelial stores, improving primary haemostasis.

Prescribing in practice

• Its antidiuretic action can cause dilutional hyponatraemia and seizures, so fluid intake should be restricted around dosing and sodium monitored, with particular caution in young children and the elderly.
• A test dose is used to confirm an adequate factor response before relying on it for haemostatic cover.
• Avoid in unstable cardiovascular disease and in those with a history of hyponatraemia, and use cautiously with drugs that potentiate antidiuretic effect.

Monitoring

Monitor fluid balance, body weight and plasma sodium when used for its antidiuretic or haemostatic effect, and check the factor VIII or von Willebrand response when treating bleeding disorders.

Counselling the patient

• Restrict your fluid intake around each dose as advised.
• Report headache, nausea, confusion or undue drowsiness, which may signal low sodium.
• Tachyphylaxis means repeated closely spaced doses become less effective.

Evidence & guidelines

Long-standing clinical experience and haemostasis guidelines support desmopressin for mild haemophilia A and type 1 von Willebrand disease where a documented response exists.