Loop diuretic

Diagram illustrating the mechanism of action of loop diuretics.

Loop diuretics are a class of diuretic medications that act on the ascending limb of the loop of Henle in the nephron of the kidney. They are primarily used to treat edema associated with congestive heart failure, liver cirrhosis, and chronic kidney disease. Loop diuretics are also used in the management of hypertension.

Mechanism of Action

Loop diuretics inhibit the sodium-potassium-chloride cotransporter (NKCC2) in the thick ascending limb of the loop of Henle. This inhibition prevents the reabsorption of sodium, potassium, and chloride ions, leading to increased excretion of these ions in the urine. The resulting osmotic effect causes water to be excreted along with the ions, leading to diuresis.

Pharmacokinetics

Loop diuretics are rapidly absorbed from the gastrointestinal tract and have a quick onset of action. They are highly protein-bound and are primarily excreted by the kidneys. The duration of action varies among different loop diuretics, but they generally have a short half-life.

Clinical Uses

Loop diuretics are used in the treatment of:

• Congestive heart failure: To reduce fluid overload and improve symptoms.
• Liver cirrhosis: To manage ascites and peripheral edema.
• Chronic kidney disease: To manage fluid retention.
• Hypertension: As an adjunctive therapy in resistant cases.

Side Effects

Common side effects of loop diuretics include:

• Hypokalemia: Low potassium levels due to increased excretion.
• Hyponatremia: Low sodium levels.
• Hypomagnesemia: Low magnesium levels.
• Dehydration: Due to excessive fluid loss.
• Ototoxicity: Hearing loss, which is usually reversible.

Examples of Loop Diuretics

Some commonly used loop diuretics include:

• Furosemide
• Bumetanide
• Torsemide
• Ethacrynic acid

Related Pages

• Diuretic
• Nephron
• Kidney
• Hypertension