What effect does mannitol have on urine output?

Mannitol is an osmotic diuretic that primarily acts by increasing the osmolarity of the renal tubular fluid. This results in a higher concentration of solutes, which prevents the reabsorption of water in the renal tubules. Consequently, more water remains in the urine as it passes through the nephrons. The presence of mannitol promotes diuresis, leading to an increase in urine output.

As an osmotic diuretic, mannitol is often used in clinical settings to manage conditions such as elevated intracranial pressure and acute kidney injury, where increasing urine flow can help to flush out toxins and reduce swelling. Its ability to effectively increase urine production makes it a valuable agent in managing fluid balance in patients.