Desmopressin (Nocturnal Polyuria)

How it works

It is a selective V2 receptor agonist that increases water reabsorption in the renal collecting ducts, concentrating urine and reducing nocturnal urine volume.

Prescribing in practice

• Hyponatraemia is the key danger: restrict evening fluid intake, check serum sodium before starting and shortly after initiation or dose change, and stop during intercurrent illness causing fluid or electrolyte disturbance.
• It is contraindicated in heart failure, conditions requiring diuretics, and habitual or psychogenic polydipsia, and caution is needed in older patients who are more prone to hyponatraemia.
• Withhold or stop if the patient develops vomiting, diarrhoea, or other illness affecting fluid balance, as advised in the SPC.

Monitoring

Monitor serum sodium before treatment, soon after starting, and if symptoms suggest hyponatraemia, alongside review of nocturia response.

Counselling the patient

• Limit fluids from a short time before the dose until the next morning.
• Stop and seek advice if you develop headache, nausea, drowsiness, or confusion.
• Do not take extra doses to control daytime urine.

Evidence & guidelines

Licensed for nocturia due to nocturnal polyuria and for nocturnal enuresis, supported by trials demonstrating reduced overnight urine output and fewer nocturnal voids.