Mannitol is a naturally occurring sugar alcohol used as a medication (primarily as an osmotic diuretic), as a food sweetener, and as a pharmaceutical excipient. In medicine, it is most commonly administered intravenously to reduce intracranial and intraocular pressure.
Medical uses
As an osmotic diuretic
- Intracranial pressure (ICP) reduction: By increasing the osmotic pressure of blood plasma, intravenous mannitol draws excess water out of brain tissue and into the blood vessels. This effect reduces cerebral edema and high ICP associated with traumatic brain injury and other conditions.
- Intraocular pressure (IOP) reduction: Similar to its effect on brain swelling, mannitol can draw fluid out of the eye’s vitreous humor to decrease elevated IOP. This is useful for conditions like glaucoma and before certain ophthalmic surgeries.
- Acute kidney injury: It promotes diuresis to help prevent or treat the oliguric (low urine output) phase of acute kidney injury. However, due to the risk of significant kidney damage, it is used cautiously and is now less common for this purpose.
- Toxic substance excretion: Mannitol can enhance the urinary excretion of certain water-soluble toxic substances.
