ATC C03 — Diuretics

Hydrochlorothiazide is a thiazide diuretic widely used as first-line therapy for hypertension and as adjunctive treatment for oedema. It is on the WHO Essential Medicines List and is available in low doses (12.5–25mg) as monotherapy or in fixed combinations.

Chlorthalidone is a long-acting thiazide-like diuretic widely used for hypertension and oedema. Several major outcome trials suggest it produces greater blood-pressure reduction and cardiovascular benefit than hydrochlorothiazide at equivalent doses, leading some guidelines to prefer it.

Furosemide is a potent loop diuretic used to treat fluid overload (oedema) in heart failure, kidney disease and liver cirrhosis, and as a second-line option for hypertension. Marketed as Lasix and as authorised generics in oral and intravenous forms.

Bumetanide is a potent loop diuretic used for heart failure, refractory oedema and hypertension. It is approximately 40 times more potent by weight than furosemide and has more reliable oral absorption, supporting its use when furosemide is ineffective or absorption is poor.

Torsemide is a long-acting loop diuretic used for heart failure and oedema, and at lower doses for hypertension. It has more reliable oral absorption than furosemide and a longer duration of action, which has supported broader uptake in chronic heart-failure management.

Spironolactone is a potassium-sparing diuretic that blocks the aldosterone receptor. It is used in heart failure, resistant hypertension, ascites and androgen-related conditions in women, and is on the WHO Essential Medicines List.

Amiloride is a potassium-sparing diuretic used for hypertension and oedema, primarily in fixed-dose combinations with hydrochlorothiazide to offset thiazide-induced hypokalaemia. It works through a different mechanism than spironolactone, blocking distal-tubule sodium channels directly.