How triamterene works
Triamterene increases the excretion of sodium ions in the kidneys and at the same time inhibits potassium excretion. Together with sodium, water is also excreted, but the diuretic effect of triamterene – like that of other potassium-sparing diuretics – is only weak.
The importance of the active ingredient lies more in the fact that it retains potassium in the body – in contrast to other diuretics, which can lead to a dangerous loss of potassium. The combination of such diuretics with potassium sparing agents such as triamterene reduces this risk.
Many drugs that tend to increase potassium levels are now used in the treatment of high blood pressure and cardiac insufficiency. As a result, potassium-sparing diuretics have become less important – they are rarely prescribed today.
Absorption, breakdown and excretion
Triamterene is taken by mouth (orally) and absorbed into the blood via the intestinal wall (but only partially). Its effect lasts for seven to nine hours, with the maximum effect being reached around two hours after ingestion.
The diuretic and its metabolic products are excreted via the kidneys in the urine. About four hours after ingestion, half of the active ingredient has already left the body.
When is Triamteren used?
There are no longer any preparations with the active substance triamterene on the market in Switzerland.
How Triamteren is used
Triamteren is used in tablet form. These are always fixed combinations of triamterene and another diuretic.
The dosage is determined by the attending physician, whereby the severity of the disease and the age of the patient play a role. The daily dose is usually 100 to 200 milligrams.
What are the side effects of triamterene?
The active ingredient often causes nausea, dizziness, vomiting and diarrhea.
Occasional side effects include dehydration (exsiccosis), sodium deficiency and an increase in blood urea levels, especially when triamterene is combined with other diuretics.
The potassium-sparing effect of triamterene can lead to an excess of potassium in the body (hyperkalemia). This risk exists above all in patients with diabetes mellitus, impaired kidney function or metabolic acidosis of the blood (metabolic acidosis).
Patients with alcohol-induced liver cirrhosis may develop a certain form of anemia (megaloblastic anemia).
What should be considered when using Triamteren?
Contraindications
Triamteren must not be taken by:
- Hypersensitivity to the active substance or any of the other ingredients of the medicine
- Glomerulonephritis (inflammation of the renal corpuscles – a form of kidney inflammation)
- Severely reduced or absent urine excretion (oliguria or anuria)
- Kidney stones (also in the past)
- Electrolyte disorders
- Reduced circulating blood volume (hypovolemia)
- Simultaneous administration of potassium or other potassium-sparing diuretics
Interactions
When combined with other high blood pressure medications, the blood pressure-lowering effect increases.
The simultaneous use of potassium-containing medications increases the risk of a potassium excess (hyperkalemia) and is therefore not recommended. The same applies to other drugs that can increase potassium levels (such as ACE inhibitors, sartans, non-steroidal anti-inflammatory drugs, cyclosporine).
The dose of amantadine (for Parkinson’s disease and influenza) and lithium (for bipolar disorder) may need to be adjusted.
The blood sugar-lowering effect of diabetes medication (insulin, oral antidiabetics) may be reduced by triamterene.
In combination with vitamin K antagonists (such as warfarin, phenprocoumon), close monitoring of the clotting time (INR value) is recommended, especially at the start of treatment.
Age restriction
The safety and efficacy of triamterene in children and adolescents have not been proven. Use in these age groups is therefore not recommended.
Pregnancy and breastfeeding
How to obtain medication with triamterene
Medication containing triamterene is only available on prescription in Germany and Austria and can therefore only be obtained from pharmacies on presentation of a doctor’s prescription.
In Switzerland, preparations containing triamterene are no longer on the market.
