Which drug acts as a potassium-sparing agent?

The correct drug that acts as a potassium-sparing agent is not Cotrimoxazole; rather, other options like Amoxicillin, Nitrofurantoin, and Ceftriaxone do not have potassium-sparing properties.

Potassium-sparing agents are typically diuretics that help the body retain potassium while losing sodium and water. Common examples include medications like spironolactone and eplerenone. Cotrimoxazole, which is a combination of trimethoprim and sulfamethoxazole, is primarily used as an antibiotic for treating various infections but does not directly interact with potassium levels in the same way that potassium-sparing diuretics do.

Understanding the function of these drugs is crucial when considering their use, especially in patients with potential electrolyte imbalances or those taking other medications that may affect potassium levels.