What is the mechanism of action (MOA) of loop diuretics?

Loop diuretics primarily work by inhibiting the reabsorption of sodium (Na+), potassium (K+), and chloride (Cl-) ions in the ascending limb of the loop of Henle in the nephron. This region of the nephron is responsible for the majority of sodium, potassium, and chloride uptake in the kidney, and by blocking their reabsorption, loop diuretics increase the excretion of these electrolytes as well as water.

The inhibition of the NaK2Cl co-transporter, which is vital for the reabsorption of these ions, disrupts the osmotic gradient necessary for water reabsorption, ultimately leading to increased urine output. This action makes loop diuretics effective in managing conditions such as heart failure and edema, where fluid overload is an issue, as well as in managing hypertension.

The other options reflect mechanisms that either do not specifically relate to loop diuretics or pertain to different classes of diuretics or renal function, which is why they do not represent the primary mechanism of action for loop diuretics.