Indications
Desmopressin is a man-made form of vasopressin, the body’s natural anti-diuretic hormone. It is used to treat central diabetes insipidus (a condition where the body makes too little of this hormone, causing large amounts of dilute urine and thirst), night-time bedwetting in children aged 5 and over, and frequent night-time urination (nocturia) in adults. Injection and nasal forms are also used in some bleeding disorders, such as mild haemophilia A and von Willebrand disease.
How It Works
Desmopressin acts on the kidneys to make them return more water to the body, so less urine is produced and it becomes more concentrated. At higher doses given by injection, it also releases clotting factors (factor VIII and von Willebrand factor) into the blood.
Dosage and Administration
The dose depends on the condition, the product (tablet, melt under the tongue, nasal spray or injection) and the person, so take it exactly as prescribed. For bedwetting and nocturia it is taken at bedtime. Limit fluids from 1 hour before to 8 hours after a night-time dose, drinking only enough to satisfy thirst. Injections are given by a doctor or nurse.
Interactions
- Medicines that can cause water retention or low sodium, such as tricyclic antidepressants, SSRIs, Carbamazepine, Chlorpromazine and NSAIDs: increase the risk of hyponatraemia.
- Loperamide: may raise Desmopressin levels.
- Diuretics: generally should not be combined, especially in nocturia.
Contraindications
- Allergy to Desmopressin.
- Habitual or psychogenic excessive drinking (polydipsia).
- Known or past low blood sodium (hyponatraemia), or SIADH.
- Heart failure or other conditions needing diuretics.
- Moderate to severe kidney impairment.
- Von Willebrand disease type 2B (for the bleeding indication).
Side Effects
Common side effects include headache, nausea, stomach pain, dry mouth and, with nasal forms, nasal congestion. The most important risk is water retention leading to low blood sodium (hyponatraemia), which is more likely in older people and if too much fluid is drunk.
Get urgent medical help if you have severe or persistent headache, confusion, unusual drowsiness, vomiting, rapid weight gain, muscle cramps or a fit (seizure), as these may be signs of dangerously low sodium.
Pregnancy and Lactation
Desmopressin may be used in pregnancy for diabetes insipidus if the doctor considers it needed. Only small amounts pass into breast milk, and it is generally considered compatible with breastfeeding on medical advice.
Precautions and Warnings
- Avoid drinking large amounts of fluid while taking it, including during sport or in hot weather, unless advised.
- Stop it temporarily during vomiting, diarrhoea or fever and ask your doctor.
- Blood sodium should be checked, especially in people over 65 and when starting or changing the dose.
Overdose
An overdose leads to water retention and low sodium, with headache, nausea, confusion and fits. Seek emergency medical help at once.
Therapeutic Class
Antidiuretic hormone analogue (vasopressin analogue).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Some nasal sprays and injections need a refrigerator at 2 to 8°C; follow the pack.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.