Amiloride Hydrochloride for Heart Failure

Amiloride hydrochloride is a prescription medication approved by the U.S. Food and Drug Administration (FDA) with certain other diuretics (water pills) to help prevent or treat low potassium levels in people with congestive heart failure.

How Amiloride Works and How It’s Taken

Amiloride is a type of potassium-conserving diuretic, also called a water pill. It works by blocking the kidneys from taking back some sodium (salt). This helps the body remove some salt and water while reducing potassium loss.

Doctors prescribe amiloride when a person with congestive heart failure takes a thiazide or another water pill that can lower potassium levels. Amiloride helps restore low potassium levels or prevent them from becoming too low in people at higher risk.

Amiloride comes as a tablet taken by mouth, usually once a day with food. In some cases, a doctor may adjust the dose or recommend taking it only on certain days.

Typical Dosing for Congestive Heart Failure

The recommended starting dose of amiloride is one 5-milligram tablet by mouth once daily, along with the person’s usual diuretic treatment.

If needed, a doctor may increase the dose to 10 milligrams per day. If potassium levels remain low, the dose may be increased further, with careful monitoring of blood electrolyte levels, including potassium.

For people with congestive heart failure, a doctor may review the need for amiloride after the initial excess fluid has been removed. The dose may be adjusted, and maintenance treatment may be taken only on certain days. Your healthcare provider may adjust your treatment based on your condition and potassium levels.

This information is based on prescribing information, but your healthcare provider may tailor your treatment plan. Always follow their guidance.

Amiloride Side Effects

In clinical studies of amiloride hydrochloride, the most common side effects occurred in about 3 percent to 8 percent of people. These include:

Diarrhea
Headache
Nausea or loss of appetite
Vomiting

Serious Side Effects and Warnings

Amiloride can cause serious side effects that may require immediate medical attention. These include:

Hyperkalemia — High potassium levels in the blood can be life-threatening.
Hepatic encephalopathy — Brain changes from severe liver disease can cause tremors, confusion, or coma in people with preexisting severe liver disease who received diuretics.

Get medical help right away if you think you are having a serious reaction.

What To Know Before Taking Amiloride

Before starting amiloride, your doctor will check your blood potassium levels and kidney function.

Tell your doctor if you are allergic to amiloride or any of its ingredients.

Tell your doctor about all medicines you take, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.

Do not take amiloride if you:

Have high potassium levels in your blood
Have anuria (cannot produce urine)
Have sudden or long-term kidney failure
Have kidney disease caused by diabetes
Are allergic to amiloride or any of its ingredients

Avoid potassium supplements and salt substitutes that contain potassium unless your doctor specifically tells you to use them.

If you are pregnant, planning to become pregnant, or breastfeeding while taking amiloride, talk with your doctor about the risks and benefits.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is amiloride for heart failure?

Amiloride helps restore or prevent low potassium levels in people with congestive heart failure who take certain other diuretics. It has mild effects on removing extra salt and water and lowering blood pressure. When added to a thiazide diuretic, it provides little extra benefit for these effects.

In a small study of 10 people with chronic heart failure, average blood potassium levels were 4.8 millimoles per liter during treatment with amiloride, compared with 4.4 millimoles per liter with a placebo (a treatment without active medication). People received 5 milligrams of amiloride daily for one month.

How long does amiloride take to work for heart failure?

Amiloride usually starts working within two hours after taking a dose by mouth. Its effect on the amount of salts, including potassium, passed in urine is strongest between six and 10 hours and lasts about 24 hours.

This does not necessarily mean that heart failure symptoms will improve within that time.

Does amiloride interact with other medicines?

Yes. Amiloride can interact with certain medicines and increase the risk of side effects. These include:

Other potassium-conserving water pills — Medicines such as spironolactone and triamterene should not be taken with amiloride because they can cause dangerously high potassium levels.
Blood pressure medicines — ACE inhibitors and angiotensin II receptor blockers (ARBs) may increase the risk of high potassium when taken with amiloride.
Cyclosporine and tacrolimus — These medicines may increase the risk of high potassium.
Lithium — Amiloride and other water pills can increase the risk of lithium toxicity, which means harmful levels of lithium in the body.
Nonsteroidal anti-inflammatory drugs (NSAIDs) — Pain relievers such as indomethacin may reduce the effects of amiloride and increase the risk of high potassium.
Potassium supplements and salt substitutes containing potassium — These should also generally be avoided unless your doctor recommends them.

Tell your doctor about all the medicines and supplements you take before starting amiloride. Your doctor may need to monitor your potassium levels and kidney function.