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Loop diuretics (water tablets)

Patient information A-Z

Examples

The following are examples of brand names of loop diuretics:

  • Furosemide
  • Bumetanide

What are loop diuretics and what do they do?

Loop diuretics are often called water tablets. If your heart or kidneys are not working properly water might build up in your body. You might get swollen ankles or feel short of breath. Water tablets help to get rid of the extra water from your body. They help your heart and kidneys to work better.

Why am I prescribed a loop diuretic?

Loop diuretics or water tablets are used to help your kidneys remove extra fluid. If you have extra fluid in your body, you may notice that you have swollen ankles or difficulty breathing. Loop diuretics work by helping your kidneys to remove more water and salt from your bloodstream.

How do I take my loop diuretic tablets?

Water tablets are usually taken once or twice a day. If you take one dose each day, you should take it in the morning. If you take two doses each day, you should take the first dose in the morning and the second dose at lunchtime - taking them later in the day could keep you running to the toilet in the night.

You will pass more urine than usual for about four hours after taking the dose.

Always follow the instructions on the label of your medicine.

Do I need to have any tests or be monitored because I am taking loop diuretic tablets?

Your doctors will monitor your kidneys and the salts such as potassium and sodium in your blood to make sure that you are not losing too much water and are becoming dehydrated. They may advise you to adjust the doses of your diuretics based on the results of these tests.

Your doctors will also check your weight as this will tell them how much fluid you have lost from your body and will also check your ankles to check for swelling caused by extra fluid.

Are there any side effects?

Water tablets can make your blood pressure a bit too low. You might feel dizzy when you first stand up. Take care to stand up slowly and get your balance before setting off walking.

Water tablets can have side effects. Tell your doctor if you get problems with:

  • Ringing in your ears
  • Muscle cramps
  • A skin rash

Tell your doctor if you notice any strange effects from taking your water tablets.

Special warnings or precautions you need to be aware of:

Water tablets can make you lose too much water from your body which is known as dehydration. If this happens you will feel thirsty and your mouth will feel dry. If you become dehydrated it is important that you contact your doctor or specialist nurse immediately.

Signs of dehydration include:

  • Feeling thirsty
  • Dry mouth
  • Dry eyes

Are there any problems taking loop diuretic tablets with any other medications?

If you take lithium tablets the levels of lithium in your blood can be affected by diuretic tablets. If you take lithium please check with your doctor before starting the diuretic tablets.

Only take tablets prescribed for you by your doctor and check with your pharmacist before taking any new medicines.

Further information

Further information about your tablet can be found in the patient information leaflet found in the tablet/capsule box or on the container.

If you have any other questions about your medication, please contact the medicines helpline on 01223 217502.

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Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

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Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge
CB2 0QQ

Telephone +44 (0)1223 245151
https://www.cuh.nhs.uk/contact-us/contact-enquiries/