What is the primary action of Furosemide (Lasix)?

Furosemide, commonly known by its brand name Lasix, primarily acts as a loop diuretic. This class of medications works by inhibiting the sodium-potassium-chloride co-transporter in the thick ascending limb of the loop of Henle within the nephron of the kidneys. As a result, Furosemide increases the excretion of water, sodium, potassium, and chloride, thereby promoting diuresis (increased urination). This action makes it particularly effective in managing conditions such as heart failure, pulmonary edema, and hypertension, where fluid overload may be a concern.

The other options do not accurately reflect the fundamental pharmacological action of Furosemide. Vasodilation refers to the widening of blood vessels, which is not the primary mechanism of action for this drug. A sedative is a medication that inhibits activity and induces calmness, while an antipsychotic is used to manage psychosis. Neither of these functions aligns with the diuretic properties of Furosemide, which is specifically designed to help eliminate excess fluid from the body.