Amiloride

Key facts

• Amiloride is a potassium-sparing diuretic. It helps the kidneys remove excess salt and water while keeping potassium in the body, unlike most other diuretics.
• It's usually taken once daily, often combined with another diuretic to balance out potassium loss, and increases urination for several hours after a dose.
• Because amiloride keeps potassium in, combining it with potassium supplements, ACE inhibitors, ARBs or other potassium-sparing drugs can raise blood potassium to dangerous levels and cause a life-threatening irregular heartbeat.
• Seek urgent care for muscle weakness, tingling, or an irregular or slow heartbeat.

What Amiloride treats

Amiloride treats fluid retention (oedema) from heart failure, liver disease or kidney disease, usually alongside another diuretic. It's also used to correct or prevent low potassium caused by other diuretics, and as an add-on for high blood pressure not controlled by other medicines.

How Amiloride works

In the kidneys, amiloride blocks sodium channels in the tubules that would otherwise let sodium be reabsorbed back into the blood. Sodium stays in the urine and water follows it, reducing fluid in the body. Unlike diuretics that act earlier in the kidney, this channel isn't linked to potassium loss, so amiloride spares potassium while it works.

Before you take it

• Do not take amiloride if you have high blood potassium, severe kidney disease, or Addison's disease.
• Tell your prescriber about all other diuretics, ACE inhibitors, ARBs, NSAIDs or potassium supplements you take, since several of these combined with amiloride can push potassium too high.
• Kidney function and blood potassium should be checked before starting and periodically during treatment, more often in older adults or anyone with reduced kidney function.
• Dehydration from vomiting, diarrhoea or hot weather raises the risk of both high potassium and kidney strain.

Side effects

Common effects include nausea, dizziness, headache and increased urination.

Stop and seek urgent medical care for:

• Muscle weakness, cramping or tingling.
• A slow, irregular or pounding heartbeat.
• Severe rash, or swelling of the face, lips or throat.

Safety essentials

• High potassium is amiloride's defining risk. Avoid potassium supplements and salt substitutes containing potassium unless a prescriber tells you otherwise, and get blood potassium checked regularly.
• Tell every prescriber that you take amiloride before starting an ACE inhibitor, ARB, or NSAID, since these combinations need closer monitoring.
• Report reduced urination, confusion or an irregular heartbeat promptly, since these can signal dangerous potassium levels.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.