Diuretics (Water Pills): medications in this class

Overview

Thiazide and thiazide-like diuretics lower blood pressure at low doses and are a first-line class for hypertension, alone or combined with an ACE inhibitor, ARB or amlodipine. Loop diuretics act faster and more strongly and are used for swelling from heart failure, kidney or liver disease. Potassium-sparing diuretics such as spironolactone and eplerenone block aldosterone, keep potassium, and improve survival in heart failure.

The classes differ in what they do to potassium: thiazides and loops lower it, spironolactone raises it, and combinations are common precisely to balance that. Blood tests after starting and dose changes are routine. Dizziness, cramps, gout flares and raised blood sugar are the other things to watch, and timing doses earlier in the day avoids a night of urination.

Chlorthalidone is longer-acting than hydrochlorothiazide and preferred by some guidelines; torsemide is better absorbed than furosemide in some patients.

How the drugs in this class differ when you pay cash

Every common diuretic is a commodity generic and most appear on flat-price generic lists; the cash price is dispensing fee and margin. The combinations with ACE inhibitors or ARBs are also generic. The practical cost issues are the number of separate prescriptions (a diuretic, a potassium supplement and a blood pressure drug are three fees) and the pharmacy’s fee structure, not the drugs themselves.

Potassium supplements are sometimes cheaper as a prescription and sometimes over the counter; the prescriber should confirm the form and dose before any switch.

Chlorthalidone is stocked less widely than hydrochlorothiazide and can be quoted higher where it must be ordered in; torsemide and bumetanide are cheap generics but again not on every shelf. If a quote seems high for any diuretic, the most likely explanation is a pharmacy that does not keep it in stock rather than the drug itself.

Medications

Which of these is right for a given person is a decision for the prescriber. The guides explain what each drug is, how it is supplied, and why its cash price varies between pharmacies. No page on this site shows a price; prices come from pharmacies responding to your actual prescription.

Questions worth asking

• What time of day should I take it?
• When will my potassium and kidney function be checked?
• Could my diuretic and blood pressure medicine be one combination tablet?
• Should I weigh myself daily, and what change should I report?
• Which over-the-counter painkillers should I avoid?