How does this medication work? What will it do for me?

This combination product contains 2 medications: triamterene and hydrochlorothiazide. Both these medications belong to the class of medications called diuretics ("water pills"). They are used in combination to treat edema (fluid retention) that occurs with congestive heart failure and disorders of the liver and kidney. It is also used to treat mild to moderate high blood pressure.

This medication works by making the body lose excess water and salt. Triamterene, called a potassium-sparing diuretic, helps the body to retain potassium, while hydrochlorothiazide causes potassium to be lost from the body. Therefore, potassium supplements are usually not required with this medication.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

Each peach-coloured, round, flat-faced, bevelled-edged, compressed tablet, engraved "novo" on one side and "25/50" on the reverse, contains triamterene 50 mg and hydrochlorothiazide 25 mg. Nonmedicinal ingredients: colloidal silicon dioxide, FD&C Yellow No. 6 Lake, magnesium stearate, microcrystalline cellulose, sodium lauryl sulfate, and sodium starch glycolate.

How should I use this medication?

Each triamterene - hydrochlorothiazide tablet contains triamterene 50 mg and hydrochlorothiazide 25 mg. The usual starting dose to treat edema (fluid retention) or high blood pressure is 1 tablet twice daily after meals. The maximum daily dose is 4 tablets divided into 2 doses.

Your doctor will increase, decrease, or leave the dose the same depending on your response to the medication. If more than 1 tablet per day is needed, it should be taken in 2 divided doses. If only one dose is needed, it should be taken in the morning after breakfast.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take this medication if you:

  • are allergic to hydrochlorothiazide, triamterene, or any ingredients of the medication
  • are allergic to sulfa medications (e.g., sulfamethoxazole)
  • are taking other potassium-sparing diuretics (e.g., spironolactone, amiloride)
  • have acute kidney failure
  • have increased blood potassium levels
  • have severe or progressive kidney disease
  • have severe or progressive liver disease

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • decreased sexual ability
  • diarrhea
  • dizziness or lightheadedness when rising from a lying or sitting position
  • dry mouth
  • headache
  • increased sensitivity of skin to sunlight
  • loss of appetite
  • nausea
  • stomach cramps and diarrhea
  • upset stomach
  • vomiting

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • hot, swollen, or painful joints
  • signs of infection (e.g., fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
  • symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
  • Signs of changes in potassium

  • confusion
  • dry mouth
  • increased thirst
  • irregular heartbeat
  • mood or mental changes
  • muscle cramps or pain
  • numbness or tingling in hands, feet, or lips
  • shortness of breath or difficulty breathing
  • unusual tiredness or weakness
  • weak pulse
  • weakness or heaviness of legs

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergy: Some people who are allergic to sulfonamide antibiotics also experience allergic reactions to triamterene - hydrochlorothiazide because of the hydrochlorothiazide component. Before you take this medication, inform your doctor about any previous adverse reactions you have had to medications, especially sulfonamide (sulfa) antibiotics.

Contact your doctor at once if you experience signs of an allergic reaction such as skin rash, itching, difficulty breathing, or swelling of the face and throat.

Diabetes: People with diabetes may find that their blood sugar level is less controlled when taking triamterene - hydrochlorothiazide. If you have diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Gout: This medication may cause a flare-up of gout symptoms. If you have gout or a history of gouty arthritis, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Kidney stones: Triamterene has been found in kidney stones. If you have kidney stones or a history of kidney stones, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Potassium levels: Increased blood levels of potassium, though uncommon, are potentially the most severe side effect with this medication. This is more likely to occur if you are 60 years and older.

Warning signs or symptoms of high potassium include numbness, muscular weakness, fatigue, paralysis of the extremities, and slow heart rate. If this condition occurs, stop taking the medication.

Potassium supplements: Potassium supplementation, either in the form of medication or as a potassium-rich diet, should not be used at the same time as triamterene - hydrochlorothiazide. Triamterene helps recycle potassium from the urine, back into the body. When it is combined with potassium supplements, high levels of potassium in the blood may result.

Low levels of potassium may also occur for some of the people taking this medication because of the potassium-lowering effect of hydrochlorothiazide.

Pregnancy: Hydrochlorothiazide crosses the placenta and may affect an unborn baby. Triamterene - hydrochlorothiazide should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: Hydrochlorothiazide passes into breast milk, and triamterene may pass into breast milk. If you are a breast-feeding mother and are taking triamterene - hydrochlorothiazide, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

What other drugs could interact with this medication?

There may be an interaction between triamterene - hydrochlorothiazide and any of the following:

  • amifostine
  • ammonium chloride
  • angiotensin converting enzyme (ACE) inhibitors (e.g., ramipril, enalapril)
  • angiotensin II receptor blockers (e.g., losartan, candesartan)
  • cholestyramine
  • colestipol
  • cyclosporine
  • digoxin
  • dofetilide
  • eplerenone
  • indomethacin
  • lithium
  • medications that reduce high blood pressure
  • nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., ibuprofen, naproxen)
  • potassium-sparing diuretics (e.g., amiloride, spironolactone)
  • potassium supplements (e.g., potassium chloride, potassium gluconate, salt substitutes containing potassium)
  • rituximab
  • sodium phosphates
  • tacrolimus
  • topiramate
  • yohimbine

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.