Skip to main content

Triamterene - a 'water' tablet or diuretic

Clinical author's note Michael Stewart 15/06/2022: Triamterene capsules were discontinued in the UK in November 2021. Currently triamterene is only available in the UK in combination with another diuretic medicine called chlortalidone. At the time of review there are no branded or generic products solely containing triamterene available in the UK. Products may still be available in other countries. This medicine leaflet is based on medical information available in the UK at the time of writing and is left here for reference purposes. Please also refer to the manufacturer's information supplied with your medicine.

Triamterene is a 'water' tablet (diuretic) - it will make you want to go to the toilet more often to pass urine.

It may cause your urine to look slightly blue in some lights - this is harmless.

Any side-effects are usually mild.

Continue reading below

About triamterene

Type of medicine

A potassium-sparing diuretic

Used for

Water retention (oedema)

Also called

Triamterene with chlortalidone

Available as

Triamterene 50 mg/ chlortalidone 50 mg tablets

Triamterene belongs to the group of medicines known as potassium-sparing diuretics. A diuretic is a medicine which increases the amount of urine that you pass out from your kidneys. They are often referred to as 'water' tablets. Triamterene is called a potassium-sparing diuretic because, unlike some other diuretics, it does not cause your body to lose potassium. It is used to treat water retention (oedema), and it is also given alongside other diuretics to reduce the amount of potassium they cause your body to lose.

Oedema occurs when fluid leaks out of your blood vessels, causing swelling in the tissues of your lungs, feet or ankles. This makes you feel breathless and your legs feel puffy. It is commonly caused by heart failure or liver disease. Triamterene prevents the build-up of this fluid by increasing the amount of urine your kidneys produce.

In the UK, triamterene is only available in combination with another diuretic medicine called chlortalidone. This combination can help cut down on the number of tablets you need to take each day.

Before taking triamterene

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 start taking triamterene it is important that your doctor knows:

  • If you are pregnant or breastfeeding.

  • If you have problems with the way your kidneys work, or any difficulty passing urine.

  • If you have any problems with the way your liver works.

  • If you have diabetes.

  • If you have attacks of gout.

  • If you have been told by a doctor that you have high levels of potassium in your blood.

  • If you have a problem with your adrenal glands, called Addison's disease.

  • If you are taking any other medicines. This includes any medicines which are available to buy without a prescription, as well as herbal and complementary medicines.

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

Continue reading below

How to take triamterene

  • Before you start the treatment, read the manufacturer's printed information leaflet from inside your pack. It will give you more information about triamterene and will also provide you with a full list of side-effects which you could experience from taking it.

  • Take triamterene exactly as your doctor tells you to. It is usual, to begin with, to take 3-5 capsules a day divided into two doses, one dose with your breakfast and the other at lunchtime. After the first week or so, your doctor is likely to ask you to take the capsules on alternate days only. The directions for taking your doses will be printed on the label of the pack to remind you about what the doctor said to you.

  • Diuretics are best taken no later than mid-afternoon. This is because you will find you may need to go to the toilet a couple of times after taking it and this will disturb your sleep if you take it too late in the day.

  • Swallow the capsules with a drink of water. You can take triamterene either with or without food.

  • If you forget to take a dose of triamterene, take it when you remember if it is only a few hours late. If it is after mid-afternoon, leave out the forgotten dose completely and take your next dose when it is due. Do not take two doses at the same time to make up for a missed dose.

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. The balance of salts in your blood may be upset by triamterene so your doctor may want you to have a blood test from time to time to check for this.

  • Diuretics help you to lose water, so you can breathe and move more easily. If, however, you lose too much fluid, you may become lacking in fluid in the body (dehydrated). This will make you feel thirsty and make your skin look and feel dry. Let your doctor know if this happens, as your dose may need to be adjusted.

  • Because triamterene is a potassium-sparing diuretic, you should try to avoid things with a high potassium content, such as 'salt substitutes'. This is so the level of potassium in your body does not become too high.

  • Treatment with diuretics is usually long-term, so continue to take triamterene unless your doctor advises you otherwise.

  • If you buy any medicines 'over the counter', please check with a pharmacist that they are suitable for you to take alongside your prescribed medicines.

  • Triamterene can cause your urine to look slightly blue in some lights - this is harmless and nothing to be concerned about.

If you are also taking hydrochlorothiazide in combination with this medicine

  • Studies have suggested that taking higher doses of hydrochlorothiazide for long periods of time may increase the risk of certain skin cancers.

  • Tell your doctor if you have ever been treated for skin cancer before.

  • Tell your doctor about any new or changed moles or worrying marks on your skin.

  • Use a sunscreen in strong sunlight. Do not use sunbeds.

Continue reading below

Can triamterene 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 common ones associated with triamterene. 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.

Common triamterene side-effects (these affect fewer than 1 in 10 people)

What can I do if I experience this?

Feeling sick (nausea) or being sick (vomiting)

Stick to simple foods - avoid fatty or spicy meals. Try taking the capsules after a meal or a snack


Drink plenty of water to replace the lost fluids

Changes to the results of some blood tests

Your doctor will check for this from time to time

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

How to store triamterene

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

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

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you are due to have an operation or any dental treatment, please tell the person carrying out the treatment which medicines you are taking.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

symptom checker

Feeling unwell?

Assess your symptoms online for free