From the Guidelines
Diuretics are classified into several major groups, including loop diuretics, thiazide diuretics, potassium-sparing diuretics, carbonic anhydrase inhibitors, and osmotic diuretics, with loop diuretics being the preferred agents for use in most patients with heart failure 1. The main classes of diuretics are:
- Loop diuretics (furosemide, bumetanide, torsemide) that act on the ascending loop of Henle and are powerful agents used for edema in heart failure, liver disease, and kidney disease
- Thiazide diuretics (hydrochlorothiazide, chlorthalidone) that work in the distal convoluted tubule and are commonly used for hypertension management
- Potassium-sparing diuretics (spironolactone, eplerenone, amiloride, triamterene) that prevent potassium loss and are often used in combination with other diuretics or for conditions like hyperaldosteronism
- Carbonic anhydrase inhibitors (acetazolamide) that reduce bicarbonate reabsorption and are used for glaucoma and altitude sickness
- Osmotic diuretics (mannitol) that increase osmotic pressure in the tubular fluid and are primarily used to reduce intracranial pressure When prescribing diuretics, it's essential to monitor electrolytes, particularly potassium levels, as well as kidney function, as these medications can cause significant electrolyte imbalances and may affect renal function 1. The choice of diuretic depends on the patient's specific condition, with loop diuretics being the preferred choice for heart failure patients with significant fluid retention, and thiazide diuretics being considered for hypertensive patients with mild fluid retention 1. It's also important to note that diuretic resistance can be overcome by escalating the loop diuretic dose, using intravenous administration, or combining different diuretic classes 1.
From the FDA Drug Label
Amiloride HCl is a potassium-conserving (antikaliuretic) drug that possesses weak (compared with thiazide diuretics) natriuretic, diuretic, and antihypertensive activity. Torsemide is a diuretic of the pyridine-sulfonylurea class.
The main classes of diuretics mentioned in the drug labels are:
- Potassium-conserving (antikaliuretic) diuretics, such as amiloride HCl 2
- Thiazide diuretics 2
- Loop diuretics 2
- Pyridine-sulfonylurea class diuretics, such as torsemide 3
From the Research
Classes of Diuretics
- Thiazide diuretics: inhibit sodium reabsorption in the early distal convoluted tubule 4
- Loop diuretics: block chloride and sodium reabsorption by inhibition of the Na/K/2Cl cotransport system in the thick ascending limb of the loop of Henle, examples include furosemide, bumetanide, piretanide, and torasemide 4, 5
- Potassium-sparing diuretics: include aldosterone receptor blockers (such as spironolactone and eplerenone) and epithelial sodium channel blockers (such as amiloride and triamterene) 4
- Osmotic diuretics: increase the flow of urine by inhibiting the reabsorption of water and electrolytes in the renal tubules 6
- Carbonic anhydrase inhibitors: primarily used in the treatment of glaucoma, but also have diuretic properties 6, 5
Other Diuretic Agents
- Vasopressin-2 receptor antagonists: possess diuretic properties, but are not included in the traditional pharmacological group of diuretics 6
- SGLT2 inhibitors: have diuretic properties, but are not typically classified as diuretics 6
Classification of Diuretics
- Diuretics can be classified according to their chemical structure, mechanism and site of action within the nephron, and diuretic potency 5
- Loop diuretics are the most powerful, causing the excretion of 20-25% of filtered sodium load, while thiazide diuretics and metolazone are moderately potent, resulting in the excretion of 5-8% of filtered sodium 5
- Potassium-sparing diuretics are only mildly potent, causing the excretion of only 2-3% of filtered sodium 5