The drug amiloride belongs to the group of potassium-sparing diuretics. The main indications for its use are arterial hypertension, heart failure, coronary heart disease, and associated edema. The drug is taken orally as a tablet or capsule.
What is amiloride?
The main indications for the use of amiloride are arterial hypertension, heart failure, coronary heart disease, and related edema. Amiloride is a drainage medication prescribed primarily for arterial hypertension, heart failure, coronary artery disease (CAD), and edema. Off-label, the active ingredient amiloride can also be used for inhalation in pulmonary diseases, but has not yet been officially approved for this purpose. The prescription drug is available in tablet and capsule form. It is common practice to always give amiloride combined with an additional diuretic – usually hydrochlorothiazide. Diuretics such as amiloride work through the kidneys, where they promote urine production and help eliminate excess water from the body. In addition, they flush out salts – such as potassium. Both lower blood pressure and thus relieve the heart. Due to its chemical properties, the active ingredient amiloride is a pyrazine derivative. As a light-sensitive substance, amiloride should be stored in the dark.
Pharmacologic Action
Amiloride exerts its full effect best in combination with another diuretic. In most cases, this involves therapy with a combination of amiloride and a thiazide diuretic such as hydrochlorothiazide. Alternatively, amiloride can be combined with a loop diuretic. The two active ingredients are used to lower high blood pressure and relieve the heart. Amiloride acts via the kidneys, where it inhibits the epithelial aldosterone-dependent sodium channel located in the late distal tubule of the renal nephron. This results in a smaller amount of sodium being reabsorbed and, as a consequence, correspondingly less potassium being excreted in exchange for sodium. In this way, potassium ions are saved. The potassium-saving effect produced in this way can increase the level of potassium in the blood to such an extent that hyperkalemia occurs, a potentially life-threatening electrolyte disturbance. In particular, concomitant therapy with ACE inhibitors or spironolactone increases the risk of this and blood potassium levels should be closely monitored. An elevated blood potassium level may well be a contraindication to the administration of amiloride. The diuretic effect of amiloride flushes out water retention from the tissues. Since salts are also lost to the body in this process, the prescription of amiloride is particularly well suited for patients in whom potassium loss must be avoided for the duration of the intended fluid excretion. Amiloride has good bioavailability, is not metabolized, and is later largely excreted in the urine.
Medical use and application
The combination preparation of amiloride with another diuretic from the thiazide group, such as hydrochlorothiazide, is used to treat elevated blood pressure, heart failure, coronary heart disease, and fluid accumulation – edema – in the tissues. Amiloride leads to increased urine excretion via the kidneys. The water retention thereby flushed out lowers blood pressure and thus relieves the heart. However, since salts also leave the body during this process, potassium loss must be avoided. As a potassium-saving drug, amiloride is ideally suited for this therapy. The dosage and duration of treatment depend on the type of disease and its severity. For example, therapy for hypertension usually starts with half a tablet per day. During long-term therapy, the dose is almost always reduced to a quarter tablet daily. In heart failure-related edema, therapy starts with half a tablet or a whole tablet daily. If necessary, the dose may be increased to a maximum of two tablets daily.
Risks and side effects
When taking amiloride and its combination agents, adverse side effects may include:
- Nausea to vomiting
- Loss of appetite
- Diarrhea
- Constipation
- Disturbances of the electrolyte balance
- Cardiac arrhythmias
- Headache
- Confusion
Amiloride is contraindicated in certain medical conditions and special life situations. These include:
- Hyposensitivity to sulfonamides (because of combination with hydrochlorothiazide).
- Hyperkalemia as well as other disorders of electrolyte balance.
- Cardiac arrhythmias
- Kidney dysfunction
- Liver dysfunction
- Pregnancy
- Lactation
Likewise, children should be excluded from treatment with amiloride.
