Which diuretic is classified as an osmotic diuretic used to reduce intracranial pressure?

Which diuretic is classified as an osmotic diuretic used to reduce intracranial pressure?

• A. Mannitol
• B. Furosemide
• C. Hydrochlorothiazide
• D. Acetazolamide

Answer: (A)

Osmotic diuretics raise the osmolarity of the tubular filtrate, pulling water from tissues into the urine. Mannitol is the classic osmotic diuretic used to lower intracranial pressure because, when given IV, it increases plasma osmolality and draws water out of swollen brain tissue into the bloodstream, reducing brain edema and ICP. It is then filtered and excreted by the kidneys, producing a rapid diuretic effect. The other diuretics work by different mechanisms and do not produce the same osmotic shift to relieve cerebral edema: a loop diuretic blocks NKCC2 in the loop of Henle, a thiazide inhibits NCC in the distal tubule, and acetazolamide reduces bicarbonate reabsorption with some CSF effects but is not the agent of choice for acute ICP reduction. Therefore, the best answer is mannitol, the osmotic diuretic used to decrease intracranial pressure.

Osmotic diuretics raise the osmolarity of the tubular filtrate, pulling water from tissues into the urine. Mannitol is the classic osmotic diuretic used to lower intracranial pressure because, when given IV, it increases plasma osmolality and draws water out of swollen brain tissue into the bloodstream, reducing brain edema and ICP. It is then filtered and excreted by the kidneys, producing a rapid diuretic effect. The other diuretics work by different mechanisms and do not produce the same osmotic shift to relieve cerebral edema: a loop diuretic blocks NKCC2 in the loop of Henle, a thiazide inhibits NCC in the distal tubule, and acetazolamide reduces bicarbonate reabsorption with some CSF effects but is not the agent of choice for acute ICP reduction. Therefore, the best answer is mannitol, the osmotic diuretic used to decrease intracranial pressure.