Endocrine
Desmopressin
A synthetic form of ADH (vasopressin) — Reduces urine production — used in diabetes insipidus and selected bedwetting.
Education and reference only. This is a plain-language class overview — it deliberately contains no doses. Always check the current Summary of Product Characteristics (SmPC), the BNF and your local formulary before prescribing or administering any medicine.
Quick answer
What is Desmopressin?
Desmopressin is a manufactured version of the body's water-retaining hormone. It reduces urine output and is used for cranial diabetes insipidus, selected bedwetting or night-time urination, and some bleeding disorders.
- How it works: It mimics antidiuretic hormone (vasopressin), signalling the kidneys to reabsorb water and so produce less, more concentrated urine.
- In practice: In practice desmopressin concentrates the urine, so it is used in cranial diabetes insipidus (where the body lacks its own antidiuretic hormone), in some cases of troublesome bedwetting or night-time urination, and in certain bleeding conditions.
What it is
Desmopressin is a manufactured version of the body's water-retaining hormone. It reduces urine output and is used for cranial diabetes insipidus, selected bedwetting or night-time urination, and some bleeding disorders.
How it works
It mimics antidiuretic hormone (vasopressin), signalling the kidneys to reabsorb water and so produce less, more concentrated urine. Because it makes the body hold on to water, drinking too much while taking it can dilute the blood's sodium dangerously.
In practice
In practice desmopressin concentrates the urine, so it is used in cranial diabetes insipidus (where the body lacks its own antidiuretic hormone), in some cases of troublesome bedwetting or night-time urination, and in certain bleeding conditions. The dominant safety issue across all uses is the risk of low sodium (hyponatraemia) from water retention, which can cause headache, nausea, confusion and, if severe, seizures. The practical safeguard is fluid restriction around dosing — patients are told to limit how much they drink from shortly before until some hours after a dose, and to stop and seek advice during any illness with vomiting or diarrhoea, or if they develop symptoms of low sodium. It is used with particular caution in the very young and the elderly, who are more vulnerable.
Examples
Practical use
How to take it & use it well
- Take desmopressin exactly as prescribed, as it comes in several forms (tablet, melt that dissolves in the mouth, and nasal spray) which are not interchangeable.
- Follow any advice on fluid intake carefully - for bedwetting this usually means avoiding drinking much in the hour before and the hours after a night-time dose.
- Do not take it during an illness with vomiting, diarrhoea or fever, or any time you cannot manage your fluids normally, and seek advice instead.
- If you miss a dose, skip it and take the next one as scheduled rather than doubling up.
- Store as directed on the label and keep follow-up appointments so your treatment and any blood tests can be checked.
Common uses
- Cranial diabetes insipidus
- Selected nocturnal enuresis (bedwetting) and nocturia
- Some bleeding disorders (specialist use)
Monitoring
- Sodium levels (especially when starting or adjusting), fluid balance and weight
- Symptom control (urine output / dry nights)
- For signs of water overload or low sodium
Weighing it up
Advantages & disadvantages
Advantages
- It replaces the body's natural water-regulating hormone, effectively controlling thirst and excess urine in diabetes insipidus.
- It can reduce bedwetting in selected children and night-time urination in some adults.
- Several formulations allow the most suitable option for the person.
- When used with correct fluid advice, it can noticeably improve sleep and daily life.
Disadvantages
- Its main risk is low blood sodium from holding on to too much water, which can be serious - so fluid restriction around dosing is essential.
- It must be paused during vomiting or diarrhoea illnesses, which can interrupt treatment.
- The very young and the elderly need extra caution because they are more prone to fluid and sodium problems.
- It treats symptoms and does not cure the underlying cause.
Key safety principles
What to watch for
- Risk of low sodium (hyponatraemia) from water retention — headache, nausea, confusion or seizures; restrict fluids around dosing.
- Stop and seek advice during illness with vomiting/diarrhoea or if symptoms of low sodium develop.
- Particular caution in young children and older adults; avoid excess fluid intake.
Key interactions
What to avoid or check alongside
- Medicines and situations that increase fluid intake or water retention add to the risk of low sodium - follow fluid advice strictly.
- Certain antidepressants, some pain relievers (NSAIDs), and water tablets (diuretics) can affect sodium balance and increase the risk of low sodium.
- Drinking large amounts of fluid, including alcohol or lots of water around a dose, raises the chance of dangerous fluid overload.
- Illnesses causing vomiting or diarrhoea change fluid balance, so the medicine should be paused during these episodes.
Patient & carer advice
- Limit how much you drink from before a dose until some hours after, as advised
- Stop and get advice if you are vomiting, have diarrhoea, or feel headachy, sick or confused
- Take it exactly as prescribed — do not take extra
Use with
Related clinical calculators
Dose and risk decisions for this class often depend on renal function, weight or bleeding/stroke risk. These tools help:
Answers
Desmopressin: frequently asked questions
Why do I need to limit fluids around my dose?
Desmopressin makes your body hold on to water, so drinking too much can dilute your blood sodium to dangerous levels. Following the fluid advice keeps treatment safe.
What should I do if I get a vomiting or diarrhoea bug?
Stop the desmopressin during the illness and seek advice, because your fluid balance is already disturbed. Restart only when you are well and able to drink normally again.
What are the warning signs of low sodium?
Headache, nausea, feeling unusually unwell, confusion or, rarely, fits can occur. If these happen, stop the medicine and seek urgent medical advice.
Can my child use desmopressin for bedwetting?
It is used for selected children with bedwetting, with careful attention to fluids in the evening. Your clinician will decide if it is suitable and advise on fluid limits.
Can I swap between the tablet, melt and nasal spray?
No - these forms are not equivalent and should not be switched without your clinician's instruction. Always use the exact form and strength you were prescribed.
Authoritative sources
Always verify against the source
This overview is for orientation. For doses, interactions, contra-indications and the full monograph, use:
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