A medicine for diabetes insipidus and bedwetting
Desmopressin
A man-made form of the body's water-balancing hormone, used to reduce excess urine in conditions such as diabetes insipidus and bedwetting.
What is Desmopressin?
Desmopressin is a man-made version of vasopressin, the natural hormone that helps the body hold on to water and pass less urine. It is used for cranial diabetes insipidus (where the body lacks this hormone), persistent bedwetting in children, troublesome night-time passing of urine in adults, and some bleeding conditions. Because it makes the body retain water, its most important risk is a fall in the blood sodium level (hyponatraemia), which can cause headache, confusion, seizures and even be life-threatening. To prevent this, fluid intake must be limited around each dose, and the medicine is paused during illnesses that affect fluid balance.
Education and reference only. This is a plain-language guide to Desmopressin — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Desmopressin is a man-made copy of vasopressin, the body's anti-diuretic hormone, which tells the kidneys to hold on to water so less urine is made. It is used in several situations: cranial diabetes insipidus, where the body does not make enough of this hormone and passes large amounts of urine; persistent bedwetting in children and night-time waking to pass urine in adults; and some bleeding disorders, where it helps the blood to clot. It comes as tablets, melt-in-the-mouth tablets, a nasal spray and an injection. It is prescribed with clear instructions about limiting fluids, because of its powerful effect on water balance.
How it works
The kidneys decide how much water to keep or pass out, guided by vasopressin. Desmopressin acts like vasopressin, signalling the kidneys to reabsorb more water, so the body makes less, more concentrated urine. In diabetes insipidus this replaces the missing hormone; in bedwetting and night-time urination it reduces how much urine is made overnight. In some bleeding conditions it works differently, by releasing stored clotting factors to help the blood clot. Because it makes the body hold on to water, drinking too much while it is working can dilute the blood and dangerously lower the sodium level, which is why fluid intake has to be controlled.
Company & origin
Originated / developed by: Specialist and generic manufacturers.
A medicine used in the UK for diabetes insipidus, persistent bedwetting and night-time passing of urine, and some bleeding conditions.
Practical use
How to take Desmopressin
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it exactly as prescribed and follow the fluid-restriction advice closely, especially limiting drinks in the hours after each dose.
- Avoid drinking large amounts of water or other fluids around the time it is working, to prevent the blood sodium falling.
- Stop it and seek advice during vomiting, diarrhoea or any illness that affects fluid balance, or if you cannot follow the fluid limits.
- Seek help promptly for headache, nausea, confusion, unusual drowsiness or a seizure, as these can signal low blood sodium.
- For bedwetting in children, give it as directed and limit drinks in the evening as advised.
Weighing it up
Advantages & disadvantages of Desmopressin
Advantages
- Effectively replaces the missing hormone in cranial diabetes insipidus and reduces excessive urine.
- Can help persistent bedwetting in children and reduce night-time waking to pass urine in adults.
- Available in several forms, including tablets, melt-in-the-mouth tablets, nasal spray and injection.
Disadvantages
- Can cause a dangerous fall in blood sodium (hyponatraemia) if too much fluid is taken, with risk of seizures.
- Needs careful fluid restriction and must be paused during illnesses that affect fluid balance.
- Older people and young children are particularly vulnerable to low sodium, so extra care is needed.
Practical use
Good to know
The single most important thing to understand about desmopressin is the risk of water overload and low blood sodium (hyponatraemia). Because the medicine makes the body retain water, drinking too much fluid while it is working can dilute the blood, and a low sodium level can cause headache, nausea, drowsiness, confusion, fits (seizures) and, in severe cases, can be life-threatening, a problem sometimes called water intoxication. To stay safe, fluid intake must be limited around each dose, particularly in the hours after taking it, and the medicine should be paused during vomiting, diarrhoea or any illness that upsets fluid balance, and whenever you cannot follow the fluid limits. Warning signs of low sodium, such as headache, feeling sick, confusion or unusual drowsiness, should be acted on quickly. Older people and young children are especially vulnerable.
Who should not take it / use with caution
- People who have had a serious allergic reaction to desmopressin should not use it.
- It should not be used by people who tend to drink excessive amounts of fluid or who cannot follow the fluid limits.
- It is avoided or used with great caution in people with heart failure, certain kidney problems or a history of low blood sodium.
- It is used with particular care in older people and in young children because of the risk of low sodium.
Monitoring
- Checking the blood sodium level, especially when starting treatment or changing the dose.
- Watching weight and fluid balance, and reviewing the fluid-restriction advice.
- Reviewing how well it is controlling symptoms and watching for signs of low sodium.
Side effects
- Low blood sodium (hyponatraemia), which can cause headache, nausea, confusion, drowsiness and, in severe cases, seizures.
- Headache, tummy pain or nausea.
- Fluid retention, sometimes with a small weight gain or swelling.
- With the nasal spray, nasal irritation or a blocked or runny nose.
Key interactions
- Medicines that themselves can lower blood sodium, such as some antidepressants, certain water tablets and some painkillers, add to the risk and need care.
- Other medicines that affect fluid balance can make low sodium more likely.
- Tell your prescriber about all your medicines, as several can increase the risk of low blood sodium.
Available as: Tablets, melt-in-the-mouth tablets, a nasal spray and a solution for injection.
Answers
Desmopressin: frequently asked questions
What is desmopressin used for?
It is a man-made version of the body's water-balancing hormone, used for cranial diabetes insipidus, persistent bedwetting in children, night-time passing of urine in adults, and some bleeding conditions.
Why do I have to limit how much I drink?
Desmopressin makes the body hold on to water, so drinking too much can dilute the blood and dangerously lower the sodium level, which can cause confusion and seizures; limiting fluids around each dose prevents this.
What are the warning signs of low sodium?
Headache, feeling sick, confusion, unusual drowsiness and, in severe cases, seizures; if these happen, seek help promptly as they can signal low blood sodium.
When should I stop taking it?
Pause it and get advice during vomiting, diarrhoea or any illness that upsets fluid balance, or whenever you cannot follow the fluid limits, as the risk of low sodium rises.
Is it safe for children with bedwetting?
It is widely used for persistent bedwetting in children, but the fluid-restriction advice must be followed carefully, particularly limiting evening drinks, because children are vulnerable to low sodium.
The wider class
About Vasopressin analogue (anti-diuretic)
Desmopressin belongs to the vasopressin analogue (anti-diuretic) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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