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Diuretics, also known as water tablets, help reduce fluid build-up in your body. Read about the types of diuretics, how they work and their possible side effects.

Types of diuretics

There are three different types of diuretics:

  • loop diuretics
  • thiazide diuretics
  • potassium-sparing diuretics.

The three types work in different ways and your doctor will talk with you about which is best for you.

Types of loop diuretics include:

  • bumetanide, also called Burinex
  • furosemide, also called Frusemide, Diurin, Lasix, Urex Forte.

Types of thiazide diuretics include:

  • bendroflumethiazide
  • chlorthalidone, also called Hygroton
  • hydrochlorothiazide - usually used in conjunction with an ACE inhibitor, also called Accuretic; or with an ARB, also called Atacand
  • metolazone
  • indapamide hemihydrate, also called Dapa-tabs.

Types of potassium-sparing diuretics include:

  • amiloride 
  • spironolactone, also called Aldactone
  • eplerenone, also called Inspra.

How do they work?

Diuretics (water pills) make you pass urine (wee) more often, removing excess fluid from your body.

This helps to lower your blood pressure, reducing pressure on your heart and kidneys.

Diuretics side effects

You may experience some unwanted side effects when taking a diuretic. These can include:

  • muscle cramps
  • dizziness
  • dry mouth/thirst.

Ring 111 if you have any of the following:

  • severe chest pain
  • severe headache
  • acute shortness of breath
  • swelling of your mouth, lips or tongue, as this could be an allergic reaction.

Talk to your doctor if your side effects are worrying you. Don't stop taking your medication without talking to your doctor first. The benefits usually outweigh the side effects.

What tests do I need?

You'll need regular GP appointments to check your weight and kidney function.

What happens if I miss a dose?

If you miss a dose, don't try to catch up. Just take your regular dose at the next time it’s due.

Do NOT take a double dose. Taking too many diuretics may damage your kidneys.

What else do I need to know?

Diuretics make you go to the toilet more, so you may want to take them in the morning or at lunchtime, rather than later in the day. Talk to your doctor or pharmacist about how you can do this safely.

If you have increased breathlessness and/or have swollen ankles, talk to your doctor or nurse as you may need your dose adjusted.

Tell your health professionals if you're taking any:

  • supplements
  • natural medicines
  • vitamins
  • alternative therapies.

These can sometimes make your heart medication less effective.

Talk to your pharmacist if you're buying over-the-counter pain relief medications or anti-inflammatories. These medications can be harmful when used together with diuretics.

Talk to your doctor if you’re on diuretics and are planning to get pregnant or are breastfeeding.

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