Desmopressin

About desmopressin

Desmopressin is used in several different conditions. It is a vasopressin analogue, which means that it is similar to a naturally occurring hormone called vasopressin. Vasopressin is also called antidiuretic hormone (ADH). ADH has an effect on your kidneys. It causes your kidneys to pass out less water in your urine, so your urine becomes more concentrated.

Diabetes insipidus is a condition in which your ability to control the balance of water within your body is not working properly. Your kidneys are not able to regulate how much water passes out in your urine as well as they should. If you have cranial diabetes insipidus, this happens because your brain is producing or releasing a reduced amount of ADH. Desmopressin has the same effect on your kidneys as ADH. It replaces the ADH that your body is lacking and so will help to control the amount of urine that you pass.

Bedwetting (nocturnal enuresis) means that a child passes urine in the night when they are asleep. Desmopressin works by reducing the amount of urine your child makes at night. There is a separate leaflet called Bedwetting Medicine (Desmopressin) which provides more information about this.

Surgery on the pituitary gland in the brain can lead to over-production of urine. This is because ADH is normally released into your bloodstream from your pituitary gland. Desmopressin is commonly given for short periods of time following this type of surgery.

People with haemophilia or von Willebrand's disease have either a deficiency or a complete lack of some blood clotting factors, and therefore have problems with stopping bleeding. Desmopressin boosts the levels of these clotting factors and helps the blood to clot more efficiently. It is used for short periods of time, such as when surgery is planned, or during bleeding episodes.

Before taking desmopressin

Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you (or, where appropriate, your child) start taking desmopressin it is important that your doctor knows:

• If you have a heart condition or blood vessel disease.

• If you have any problems with the way your kidneys work.

• If you have any of the following conditions: high blood pressure, asthma, epilepsy, migraine or cystic fibrosis.

• If you have an alcohol problem or addiction.

• If you have ever had an allergic reaction to a medicine.

• If you are pregnant or breastfeeding.

• If you are taking or using any other medicines. It is particularly important that you tell your doctor if you are taking a 'water' tablet (diuretic). You should also tell your doctor about any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

How to take desmopressin

• Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about the preparation you have been given, and will provide you with a full list of side-effects which you could experience. Not all brands of desmopressin are suitable for all the conditions listed above, so it is important that you read and follow the information that comes with your supply.

• Take desmopressin exactly as your doctor tells you to. Your dose will depend upon the reason you are taking it. Your doctor will tell you what the correct dose is for you and also how to administer it. The directions will also be printed on the label of the pack to remind you about what the doctor said to you.

• If you have been given standard tablets (brand names DDAVP®, Desmotabs®), these can be swallowed whole with a drink of water, or can be crushed before swallowing.

• If you have been given tablets to 'melt' in your mouth (brands DDAVP Melt®, DesmoMelt®), place the tablet under your tongue and allow it to dissolve completely. If it breaks into pieces as you are taking it out of the packaging, this may mean that you do not receive the correct dose. If this happens, unwrap another tablet and do not use the broken one.

• If you are using intranasal solution, you will have been told how to measure out your dose. If you are still unsure, ask your pharmacist or practice nurse to show you again.

• If you have been given desmopressin spray, prime the spray before you use it for the first time, by pressing several times until you see a fine mist.

• If you miss taking a dose or if you take more doses than you should, speak with your doctor or practice nurse for advice on what to do.

Getting the most from your treatment

• Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.

• Do not drink large quantities of fluids, as this can lead to a build-up of water in your body. Too much fluid can reduce the level of salts (electrolytes) in your body. This can sometimes cause serious symptoms like fits. Make sure you have discussed with your doctor how much fluid you should drink each day.

• If you are taking desmopressin for bedwetting or having to go to the toilet frequently during the night, it is important that you drink as little as possible from one hour before you take desmopressin to eight hours afterwards.

• If you are sick or have diarrhoea while you are taking desmopressin, you may need to miss out some doses until you are drinking normally again. Your doctor or practice nurse will be able to advise you about what to do.

• If you are a swimmer, it is important that you do not swallow water as you swim. Ask your doctor for advice about whether swimming is recommended for you.

• If you are due to have an operation or dental treatment, please tell the person carrying out the treatment that you are taking desmopressin.

• If you buy any medicines 'over the counter', please check with a pharmacist that they are suitable to take with desmopressin. Some medicines (for example, loperamide for the treatment of diarrhoea) may not be.

Can desmopressin cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the ones associated with desmopressin. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

If you experience any other symptoms which you think may be due to the medicine, please speak with your doctor or pharmacist for further advice.

How to store desmopressin

• Keep all medicines out of the reach and sight of children.

• Store in a cool, dry place, away from direct heat and light.

• Some brands of intranasal solution should be stored in a fridge - please check the pack label for more information.

Important information about all medicines