Indications
Triamterene is a mild water tablet (diuretic) that saves potassium. It is mostly used together with a thiazide diuretic such as Hydrochlorothiazide to treat:
- High blood pressure
- Fluid build-up (oedema) due to heart failure, liver cirrhosis or kidney problems
- Prevention of low potassium levels caused by other diuretics
How It Works
Triamterene acts on the last part of the kidney tubules. It blocks sodium channels there, so a little more salt and water are passed in the urine while potassium is kept in the body. When combined with a thiazide, the two medicines work together to lower blood pressure and remove fluid, while the triamterene balances the potassium loss caused by the thiazide.
Dosage and Administration
Take exactly as prescribed. Combination tablets with Hydrochlorothiazide are commonly taken as 1 tablet once daily in the morning, which the doctor may adjust. Take it after breakfast so that extra urination does not disturb sleep. Do not change the dose or stop it suddenly without medical advice.
Interactions
Using it with potassium supplements, salt substitutes containing potassium, other potassium-sparing diuretics (Spironolactone, Amiloride), ACE inhibitors (such as Enalapril, Ramipril), angiotensin receptor blockers (such as Losartan) or Trimethoprim can raise potassium to dangerous levels. NSAIDs, especially Indomethacin, can harm the kidneys when combined with it. It may raise Lithium levels and can increase the effect of other blood pressure medicines.
Contraindications
Do not take triamterene if you have high blood potassium, severe kidney disease or are passing little or no urine, severe liver disease, or an allergy to triamterene. It is also avoided if you are taking other potassium-sparing medicines or potassium supplements without medical supervision.
Side Effects
Possible side effects include:
- High blood potassium
- Nausea, vomiting, diarrhoea and dry mouth
- Dizziness, tiredness, headache and muscle cramps
- Skin rash and increased sensitivity to sunlight
- Kidney stones (rare)
- A bluish glow in the urine under certain light (harmless)
Get urgent medical help if you have muscle weakness, numbness or tingling, a slow or irregular heartbeat, fainting, much less urine, severe flank pain, yellowing of the skin or eyes, or signs of a serious allergic reaction.
Pregnancy and Lactation
Diuretics are generally not used for routine swelling in pregnancy. Triamterene should be used in pregnancy only if a doctor considers it necessary. It passes into breast milk, so breastfeeding mothers should discuss alternatives with their doctor.
Precautions and Warnings
Your doctor will check blood potassium, sodium and kidney function regularly, especially at the start and in older people or people with diabetes. Tell your doctor if you have kidney stones, gout, diabetes, liver disease or folate deficiency. Avoid potassium-rich salt substitutes unless advised. Use sun protection.
Overdose
Overdose may cause dehydration, low blood pressure, nausea, vomiting, weakness and dangerous changes in potassium leading to heart rhythm problems. Seek emergency medical care immediately.
Therapeutic Class
Potassium-sparing diuretic.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.