Potassium-sparing diuretics: what they do and when to use them

Here’s a quick reality check: not all diuretics lower your potassium. Potassium-sparing diuretics are the ones that help your body get rid of extra fluid but keep or raise potassium levels. That makes them useful in certain situations — and risky in others. This page gives you the facts you need: what these drugs treat, common examples, the main risks, and simple safety steps you can follow.

Common drugs and how they work

The group includes two types: aldosterone antagonists and epithelial sodium channel blockers. The most common drugs you’ll hear about are:

• Spironolactone — used for heart failure, resistant high blood pressure, ascites, and sometimes acne or hirsutism in women. Typical doses: 25–100 mg/day depending on the condition.
• Eplerenone — works like spironolactone but with fewer hormone-related side effects. Often 25–50 mg/day for heart failure or post-heart attack care.
• Amiloride — usually 5–10 mg/day, often combined with other diuretics to reduce potassium loss.
• Triamterene — another option (50–100 mg/day) that’s sometimes paired with thiazides to balance potassium.

Mechanically, aldosterone blockers stop the hormone that causes the body to hold sodium and lose potassium. Channel blockers directly reduce sodium uptake in kidney tubules, which also reduces potassium loss.

Safety: monitoring, side effects, and buying tips

The big risk here is hyperkalemia — too much potassium. That can cause weakness, irregular heartbeat, or worse. People with chronic kidney disease, those on ACE inhibitors/ARBs, or anyone taking potassium supplements or salt substitutes are at higher risk.

Simple safety steps to follow:

• Get a baseline potassium and creatinine before starting treatment.
• Check labs again within a week or two after starting or changing dose, then periodically as directed by your doctor.
• Avoid potassium supplements and salt substitutes unless your doctor says it’s safe.
• Tell every provider and pharmacist you see that you’re taking a potassium-sparing diuretic — interactions matter.

Common side effects include dizziness, stomach upset, and, for spironolactone, hormonal effects like breast tenderness or menstrual changes. Eplerenone tends to have fewer hormonal side effects but is more expensive in many places.

If you’re thinking about buying meds online, read our guide “Where to Buy Spironolactone Online Safely: Complete Guide for 2025” on this site. Make sure any online seller asks for a prescription and shows licensing info. Don’t skip lab checks just because a purchase was easy.

Want quick next steps? If a doctor suggested one of these drugs, schedule blood tests and ask how often to repeat them. If you’re researching options for edema, high blood pressure, or acne, compare benefits and side effects with your clinician before starting treatment.